MXPA97006414A - Electrostation compositions and methods for the mi - Google Patents

Abstract

A method for forming a coating on an electrically conductive surface is described, the method comprising the steps of immersing the surface in a bath comprising an electrodepositable mixture of an intrinsically insulative electrodepositable polymer of an intrinsically insulating polymer and an organic acid salt of a polymer. intrinsically conductive, apply a voltage between an electrode and the surface in the bath to deposit a polymeric coating of the mixture on the surface, and cure the polymeric coating, the polymeric coating can be made electrically conductive by the additional step of immersing the polymeric coating in an organic acid after the deposition and before curing it, a multi-layer coating can be provided after curing the electrically conductive polymeric coating, depositing a second or subsequent coating of an electrodepositable organic resin from an aqueous bath containing the resin with the application of a voltage between an electrode and the electrically conductive polymer sub-coating in the bath, resin compositions suitable for cationic electrodeposition are also described.

Description

COMPOSITIONS OF ELECTRO EVESTI MENT AND METHODS STOP THE SAME BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to electrostatic compositions and methods for forming coatings and more particularly to electrodeposition compositions comprising organic acid salts of electrically conductive polymers and methods for forming coatings therefrom.

Description of the Related Art Cathodic electrodeposition uses direct current to cause electrolytes positively charged in an aqueous medium to form coating on the cathode. Electrolytes are commonly polymers with basic groups in the form of primary, secondary or tertiary amines or quaternary ammonium, suifonium or phosphonium groups, neutralized with an organic or inorganic acid. Common resin compositions used in cathodic electrodeposition are modified epoxy resins containing amino groups. The resins are dispersed in water neutralizing with organic acid. The crosslinking agents which are typically blocked isocyanates are mixed with the resin to effect the curing of the film, applying heat after electrorepositioning. The charged polymers are dispersed in an aqueous medium so that after applying voltage between an article having a conductive surface serving as a cathode and a co-electrode, both of which are in contact with the aqueous medium, the positively charged polymer migrates towards the conductive surface. Rhi the polymer loses its charge, becomes insoluble and forms an insulating film on the conductive surface. 01 progressing the deposition, the conductive surface becomes isolated, which allows to come! It is also a uniform coating even on the remote areas, that is, the interior or depressed areas. However, this isolation of the conductive surface by means of the deposited layer also has the effect of limiting the thickness of the film in practice to a maximum of about 35 to 50 microns. The cathodic electrodeposicion provides excellent coatings that protect against corrosion for cars and for utensils while decreasing the use of volatile organic solvents for paint. When metals are electrocoated, pre-treatment is required to obtain optimum corrosion resistance for the coating. A chrome coil is normally used as a pret ra tion. However, it is considered that chromium has a high risk of toxicity and, therefore, an electrocoating method that does not require a pret ratament with chromium would be desirable. The International application UO "33/14166 discloses an anticorrosive paint comprising a binder and an electrically conductive polymer which according to the description would be applied by electrodeposition.The binders described include epoxy resins with ent relators and electrically conductive polymers which They include polyaniline impurified with an organic acid.It is mentioned that electrodeposition is one of the possible ways to apply the paint.The description would be that negatively charged paint particles can be applied in an anodic deposition process (page 44 of WO 93/14166) However, such a process is inapplicable to the deposition of the polyelectrolyte posiively charged with a polyanilma salt, therefore, this reference teaches a non-applicable method for deposition. 38 02 616 teaches polymerization and the subsequent formation of polymer films They comprise polymers or polyrnesols of heterocyclic aromatics such as pyrroles and thiophenes, and binders such as epoxy resins, aliphatic resins, acrylic resins or polyesters. The films are formed by the electrolytic brightening of the pyrogen monomer or thiophene or an anode in the presence of a binder. The presence of an organic acid is also described, such as benzenesulonic acid, in the reaction medium. Likewise, the desire to use a depositable anodicarbonant binder is described to ensure that both the polimerized monomer and the binder are deposited on the same electrode. The ET.U.Q patent No. 5,128,396 discloses a coating composition comprising a film-forming binder such as an epoxy ream with polyamide together with a keto-acid amine salt. One of the amines described was aniline. The addition of the keto acid amine salt provided an improved coating composition that could be applied by electrodeposition. However, this reference does not disclose the addition of an organic acid salt of a polymer base. Moreover, it has been generally observed in the electrodeposition technique that low-molecular-weight species are undesirable in cross-wind elect because they can cause distortion and rupture of the film (Uisiner et al., 3 Coat ngs Technol 54: 35-44, 1982). In this way, it would be desirable in the electrodeposition technique to provide a composition and electrospinning method that confer excellent corrosion inhibition on the coating and that can be electrodeposited without requiring pretreatment of the metal with chromium. It would also be desirable to provide a component of the electrodeposited coating that would allow the film to be electrically conductive. Such a passivate coating the anodic sites on a metal surface and would provide optimum protection against corrosion. If a base coat were electrically conductive, it would allow the application of a second and subsequent coatings by electrodeposing to obtain a greater thickness than could be obtained with a single coating or to obtain multiple layers of different composition. In this way, it would be desirable to be able to electrically and easily deposit a coating having a thickness of more than 35 to 50 microns and having multiple layers of the same or different composition.

BRIEF DESCRIPTION OF THE INVENTION Therefore, the present invention is directed to a novel method for forming a coating on a conductive surface which comprises immersing the electrically conductive surface in an aqueous bath which comprises an electable mixture of a intrinsically insulating polymer (IIP) and an organic acid salt of intrinsically conductive polymer (ICP). A voltage is applied between the conductive surface and an electrode to deposit a coating of said polymeric mixture on the surface. The coating of the polymer mixture is electrically insulating when deposited. As used herein, "ICP" is a polymer that is provided when an electrodeposited coating can be converted to a conductive state by exposure to an organic acid such as p-toluene sulfonic acid. 0.5 M. ICP's within the scope of this invention are typically organic polymers that have a system of iconic poly n electrons such as polyamyl, polypyrrole, poly thiophene and derivatives thereof. As used herein, "IIP" is a polymer that when provided as an electrodeposited coating can not easily be converted to a conductive state by exposure to an organic acid such as p-tol acid. 0.5 M S l lonic acid. Typical TIP's include, but are not limited to, epoxy resins, polyurethane resins, aminoplast resins, acrylic reams, or mixtures thereof. The present invention is also directed to a method for forming an electrically conductive coating on an electrically conductive surface, in which a polymecopcoate coating is first deposited and then, before curing, the coating is immersed in an organic acid. The present invention is also directed to a method for forming a coating having a thickness of about 60 microns, electrodeposing one or more subsequent polyester coatings onto electrically conductive polyester sub-coatings. In this way, the present invention is also directed to a method of electrodepositing multiple coatings, eg, coatings that provide different properties, such as a protective overcoat on a conducting primer. The present invention is also directed to a composition for forming a coating in an electrodeposition process comprising water, an electrodepositable mixture of? TTP and a salt of organic acid of? N.

TCP. Among the various advantages that have been discovered can be obtained by the present invention, one can thus note the provision of a method for forming an electrically insulating coating; the provision of a method for forming an electrically conductive coating; the provision of a method for forming an electrically conductive coating having a plurality of layers; and the provision of a composition that can be used to form a coating that has electrically insulating or conductive properties.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES In accordance with the present invention, it has been discovered that after applying a voltage between an electrically conductive surface and an electrode, both of which contact an ion bath comprising water, IIP and an organic acid salt of? n TCP, a pei icula is deposited on the surface. IIP typically includes curator groups. The polymeric coating thus formed is electrically insulating. Surprisingly, the coating can be made conductive by immersing the polyester coating in an organic acid after deposition, but before curing. The organic acid may be the same organic acid comprising the polymer salt or a different organic acid. Moreover, after the polyrnery coating is curedThe process can be repeated to apply a second and, if desired, subsequent layers on the initial coating to obtain a coating of any desired thickness. When provided with an electrospun coating, the ICP can be converted to a conductive state by exposure to an organic acid such as 0.5 M p-toluene sulfonic acid. The TCP's within the scope of this invention are typically organic polymers that they have a conjugate poly conjugate n ~ elec system. (See Naar ann, H. and Theophilo ?, N ", Synthesis of new eletronical and conductmg polymers m Electroresponsive Molecular and Polyrneric Systems, TS otheirn, ed., Marcel Dekk-er, Inc., 1988, pp. 1-39. Examples of TCP's suitable for use in the present invention include polyaniline, polypyrrole, poly thiophene, poly (3-alkylethenophenes) such as poly (3-octyl) thiophene), poly (3-methylene thiophene) and poly (3-t? in? lmet? lacetato), pol diacetylene, polyacetylene, pol iquinol a, polyheteroap lenvmileno, in which the heteroapleño group can be thiophene, furan or pyrrole,? oli- (3 ~ t? en? let lacetato), and the like, as well as derivatives, copolymers, and mixtures thereof The polymer can typically exist in various valence states and can be converted inversely in different states by electrochemical reactions. numerous valence states such as a reduced state (leucoemeraldine), a partially oxidized state do (emerald a) and a completely oxidized state (permgraniline). Polyanil a is more conductive in its emerald form. This partially oxidized state of the polyamyl can be obtained by impurifying the polyamide with any suitable organic acid to form the 1CP salt. Useful organic acids to form the salt related to the present invention include organic sulfonic acids, organic acids containing phosphorus, carboxylic acids or mixtures thereof. Examples of useful organic sulphonic acids are p-toluene sulphonic acid, camphor sulphonic acid, dodecylbenzene sulphonic acid, dinonylnaphthalenesulphonic acid, acid d or Ina talenodisul fon or mixtures thereof. The polypnepca salt can be formulated in a solution or emulsion in an organic solvent vehicle. The carrier solvent is one in which the polymeric salt is substantially soluble, and which can form a dispersion with the binder of the beef composition. The carrier solvent is a nonaqueous organic solvent having a dielectric constant typically of less than about 17. Typical vehicle solvents include xylene, toluene, 4-meth? I-2? -entanone, t-pyrrolethylene, butylacetate, 2-b Toxiethanol, n-decyl alcohol, chloroform, hexanes, cyclohexane, 1-pentanol, 1-butanol, 1-octanol, 1,4 dioxane, cyclohexane and m-cresol. Mixed solvents can also be used. The poly-salt of the present invention is soluble in these solvents at a concentration equal to or greater than 1% by weight. TCP can be prepared by any number of methods including polymerization of aqueous solution, emulsion polymerization or the like. When prepared by emulsion polymerization, the organic phase can serve as the carrier solvent. In this manner, the polymer composition within an organic phase can be used as the polimeric salt composition of the present invention. (For example, see U.S. Patent No. 5,457,162). The electrodeposition composition in the immersion bath also includes an ionic TIP. When provided with an electrodeposited coating, however, the IIP can not easily be converted to a conductive state by exposure to an organic acid such as a 0.5 M p-toluene sulfonic acid. Typical IIP's include, but they are not limited to epoxy reams, polyurethane resins, ammoplastic resins, replenishers or mixtures thereof. The ionic IIP serves as a component of the electrodeposition resin before the formation of the coating. In the elect surrounding resin an ionic IIP is conductive by virtue of its ionic containment groups introduced therein. Ionic groups make TTP dispersible in water and include, but are not limited to, cationic groups such as primary and secondary amines solubilized with acids, tertiary amines sol ied with acids, quaternary ammonium acid salts, quaternary ammonium hydroxide, acid salts of quaternary phosphine, acid salts of sulfonam ternary or carboxylate as a quaternary. For many applications, e.g., as a binder for an ICP, the preferred ionic TIP's are epoxide cationic with quaternary ammonium salts or amine salts. The predominant class of epoxy reams used in electrodeposition is the epoxy glycidyl ether type of resin. The most prominent of these are the epoxy resins based on bisphenol-0 and epichlorhydrin produced by a condensation reaction of bisphenol-polyhydroxylic acid with epichlorhydride in the presence of lcali. The production of a durable and high molecular weight coating is achieved by a curing or polymerization mechanism. In this way, the IIP may also include curing or entanglement groups. An example of an interlacer is a blocked isocyanate that is stable at bath temperatures but is unblocked and interconnected at reasonable cooking temperatures. The curing or relining of the epoxy resins can also be achieved using the inelami / hi droxyl or urethane / hydroxyl entanglement bond, both of which can be cured by treatment. In addition to the IIP and the organic acid salt of the TCP, the resin composition may also contain additional components. For example, pigments may be included in the resin composition. Suitable pigments have a low content of single soluble constituents that adversely affect the stability, corrosibility and conductivity of the bath, as well as the performance of the film. The pigment must be dispersible and resistant to flocculation and sedimentation, as well as be capable of imparting the desired color and gloss to the film. The content of pigment to IIP is usually 50% or less by weight, to allow an adequate flow of the film with high film solids, as well as to provide a low viscosity environment for the suspension of the pigment. Any pigments that meet the above criteria are considered adequate and can be included in the composition of res. When an electrically conductive film is desired, the polymer coating can be immersed in an organic acid after the coating is formed and before the film is cured. The organic acid may be the same organic acid that was used to form the ICP salt or it may be a different organic acid. Typical organic acids useful for treating the film and making the film electrically conductive include organic sulfonic acids, organic acids containing phosphorus, carboxylic acids or mixtures thereof. Useful organic sulfonic acids are p-toluene sulphonic acid, camphor sulfonic acid, dodecyl sulfonic acid benzene, dinonylnaphthalenesulonic acid, dmonylnaphthalenedi sulphonic acid or mixtures thereof. The method and composition of the present invention can be used to virtually coat any electrically conductive surface including a metal surface or a surface comprising an electrically conductive coating on a glass or plastic. When the electrically conductive surface is metal, it can be virtually any metal including silver, aluminum, iron, nickel, copper, zinc, cobalt, lead, iron-based alloys such as steel, tantalum, titanium, zirconium, niobium, chrome , and the like, and alloys thereof. The preferred metals are aluminum and steel and the alloys thereof and particularly preferred is the steel alloy. The metal surface or object can have virtually any shape or shape and includes thin films of metal that have been deposited by sputtering or similar methods on a non-metallic substrate. When the glass or plastic forms the substrate for the electrically conductive surface, the surface may comprise a coating comprising an electrically conductive material, such as a conductive polymer composition. (See patents of U.S. Nos. 5,457,462 and 5,532,025; see also the patent of E.U. A. No. 4,983,690, patent of F.U.A. No. 5,160,457, and patent of E.U.A. No. 4,678,601). For example, a urethane primer composition containing a polyaniline salt can be applied as an electrically conductive film to the surface at a time before electrodeposition of the coating. When an electrically conductive coating is applied to a surface, the present method and composition are applicable to any of a wide variety of substrates including three-dimensional objects. The electrodeposited coating of the present invention also provides advantages from the incorporation of an ICP such as a polyaniline into the electrodeposited film. Polyaniline is a TCP in which the electrical properties are determined by the oxidation state of the irnine nitrogen atoms. A wide range of desirable electrical, electrochemical and optical properties as well as excellent environmental and thermal stability are exhibited by polyaniline. Moreover, the presence of the IIP in the resin composition and in the subsequent coating imparts suitable adhesion properties to the film so that the coating is able to adhere to an electrically conductive surface. This avoids the problem of deeming from a metal surface that can occur when an ICP is applied alone.

The composition of the present invention can be used to produce a film which is capable of direct application by electrodeposition to an electrically conductive surface or object and the film thus produced will adhere sufficiently to the surface in such a way that it not be removed in a normal adhesion test such as the OSTM # D3359 test. This test generally includes drawing an "X" or a series of cross-shaped stripes on the coating layer to expose the bare metal, applying masking tape to the scratched portion, removing the adhesive and observing if anything of the coating The coating is removed and the amount of coating that is removed is compared to a normal classification table for the adhesion test as designated in the OSTM # D3359 test, or to the adhesion test accepted by the coatings industry. The resin composition contains by weight from about 0.05 to about 95% ICP in carrier-organic solvent; and from about 1 to about 95% of PII; and from about 1 to about 95% water. Preferred resin compositions contain from about 0.1 to about 50% of TCP, from about 10 to about 80% of IIP; and from approximately 10 to approximately 80% water. The most preferred resin compositions contain from about 0.5 to about 25% ICP; from about 20 to about 70% of PII; and about 20 to 70% water. The electrodeposition is carried out at a selected temperature to be between about 25 ° C to about 90 ° C and the bath temperature is maintained at the selected constant temperature _ * _ about 5 ° C by any method known and recognized in the art. technique. The ream is also stirred during the process of elect surrounding to provide dispersion of the composition of r-esine. Electrodeposition for only a few minutes, usually from about one to about 20 minutes, can be carried out at voltages of up to about 500 volts. Most preferably, the elect surround is for about 0.5 to about 10 minutes at a voltage of up to approximately 200 volts. In many cases it is advantageous to use a lower voltage of less than 75 volts. The methods and compositions herein can provide polymeric reversals when a voltage of 75 volts or less is applied. When desirable for certain applications, the present invention may also provide polymeric coatings at voltages even lower than, for example, 50 volts and even as low as 20 volts. After electrodeposition of the coating, the surface and coating on the ism is rinsed with deionized water, air dried and cured. When curing is by heat-, the polyinepco coating is baked at a temperature of up to about 250 ° C and typically of about 150 ° C for a period of from about 30 minutes to about 10 hours. When it is desired that the film be electrically conductive, the surface and coating on the ism are contacted with a solution containing the organic acid used to impurify the film and convert it into the conductive form after rinsing with deionized water. This can be done by rinsing with an aqueous solution of the organic acid. Alternatively, the surface and film thereon can be washed with deionized water and immersed in a bath containing the organic acid solution. The contact of the film with the organic acid solution is for a period sufficient to doom the film, typically for a period of from about one to about 5 minutes. The surface is subsequently cured. A particular advantage of impurifying the electrodeposited coatings with an organic acid is in the nature of the anticorrosive protection provided. An organic acid as an additive for a coating provides the inhibition of corrosion thanks to the passivation of the anodic sites. A particular organic acid that is believed to provide protection against corrosion is di-naphthaphthalene sulfonic acid co. In this way, the impurification with an organic acid as a counter ion in a coating comprised of a polypnepca salt, provides an upper coating that is capable of passivating anodic sites on a metal surface. Moreover, a coating made by means of the present invention avoids the problem of environmental risk resulting from the use of lead or chromium in corrosion inhibitors. The ability to electrically conduct the coating allows a second and subsequent repetition of the electing method to provide a coating of any desired thickness. Coatings comprised of multiple electrodeposited layers of similar or different composition can be produced in this manner by repeated electrodeposition. In some circumstances, it may be advantageous to apply a subsequent coating by an anodic electrodeposition process. For example, application of current to the contaminated backwash may cause the negatively charged organic acid counterions to run out of the reverse to effectively disengage the coating. In such circumstances it may be advantageous to prepare a multi-layer coating alternating between cathodic and anodic electrodeposition for successive layers. It may also be desirable to prepare a multilayer coating by the electroplating method of the present invention, wherein each layer has a particular function. A base coat can serve as a function of metal filler to cover the roughness of a steel surface and to mask imperfections resulting from pressing and assembly operations. Moreover, the coatings produced by the present invention can provide a base coat that produces corrosion inhibition protection by passivating anodic sites on the metal, while providing good adhesion to the base metal. A coating overlay can also be provided by means of the present invention, in which additional corrosion protection is provided in the form of a protective barrier against corrosive substances and / or to provide a decorative appearance. In addition, the overcoat may comprise a metallic base coating with a transparent coating applied over the metallic coating. All of these multi-layer coatings can be provided by means of the present invention by virtue of the ability to make each electrically conductive coating to allow the application of a subsequent coating layer.

Industrial Applicability Accordingly, the present invention is useful for providing a protective coating to a wide variety of articles. In particular, applied to automotive undercuts, corrosion protection liner will also be provided which can also be resistant to small stone fragments, also providing a decorative appearance. Pretreatment of the metal surface with bromide or chrome composites is not required to provide protection against corrosion and to improve the adhesion of the organic coating. The binder provides good adhesive properties and the organic polymer salt of a polymer base provides good corrosion protection. Odernás, the use of electrodeposition reduces substantially the quantities of volatile organic solvents that are released into the atmosphere and that can be more than 12 liters per automobile when the painting process is used. This is particularly important to satisfy the parameters for the emission of solvents. The ability of the method of this invention to provide an electrodeposited coating with a thickness of more than 60 microns, as well as to provide a multilayer coating having the same or different compositions in successive layers, substantially reduces the use of volatile organic solvents.

EXAMPLES An ionic TIP used in the following examples and known as CATHOGUARD® is an aqueous emulsion of an epoxy ream and a thermally activatable interlayer prepared by mixing the LEAD AND CROME FREE CATHOGUARD * emulsion (manufacturer number T28AD012) and the LEAD FREE ELECTROCOAT PASTE "( manufacturer number G28AD016), both obtained from BOSF Corp., Parsippany, NJ and thoroughly mixed by a magnetic stirrer for about nine days The preferred embodiments of the invention are described in the following examples. claims of the present will become apparent to a person skilled in the art from consideration of the description or practice of the invention as described herein.

REFERENCE EXAMPLES 1-9 The following examples illustrate the preparation of an electrodeposited coating on various electrically conductive surfaces under different deposition conditions. The ream of the electrodeposition bath was prepared by combining 102.3 grams of the CATHOGUARD * emulsion of BASF, 23.9 grams of the CATHOGUARD * paste of BASF, and 124.2 grams of desiomated water. This was done by combining approximately half of the water with the emulsion under agitation, which was subsequently continued until the end of the electrodeposition process. The paste was weighed in a separate container and then added to the emulsion-water mixture. The remaining half of the water was subsequently used to rinse the pulp container and then added to the mixture. The mixture was then poured through a 35 micron filter bag, type BMNO 35 (Filter Specialists, Inc., 100 Anchor Road, Michign City, IN) in a 400 ml flask. A mesh of stainless steel designed to wrap around the inside of the 400-ml flask served as an anode. A thermostatically controlled hot plate with agitator was used to maintain the bath at a constant temperature with continuous agitation by means of a stir bar. A Sorensen model DCR300-2.5 power supply was used to provide direct current for electrodeposition.

REFERENCE EXAMPLE 1 An aluminum electrode of 4 by 0.5 cm was rubbed with rnetanol, suspended in the bath liquid and connected to the negative electrode. The bath temperature was 80 ° C and the voltage was 190 volts, which generated a current of less than 2 amperes and the galvanization time was 4 minutes. After completing the electrodeposition process, the electrode with the film deposited thereon was rinsed with deionized water, air-dried and heated overnight to curdle in an oven at 150 ° C under a nitrogen atmosphere. at a reduced pressure of 50.8 crn Hg. A mottled yellow coating was obtained. 73 REFERENCE EXAMPLE 2 A test sample of carbon steel 2 by 7 cm (carbon steel C1018) was coated with the polyanilic salt of a proton-acid analyzer sold under the trade name "Versicon®" (Allied-Signal Inc. , Buffalo, NY), hereinafter referred to as C-PANI, in a poly (v? N? Lbut? Ral) formulation (PVB) (22% of C-NAPI by weight of PVB). This formulation was prepared as follows. 16 grams of PVB were dissolved in 60 grams of methyl letiicetone and 60 grams of absolute ethanol. 4.5 grams of C-PANT was added and the mixture dispersed using a ball mill overnight with 1.27 cm porcelain balls in a 400 ml mill. This mixture was designated Part A. 7.5 Grams of 85% phosphoric acid were dissolved in 92.5 grams of n-butanol. This solution was designated Part B. 30 ml of each of parts A and B were mixed and coated by spraying on steel test samples using a production air brush (McMaster-Carr Co., Chicago, 111). The coated test samples were subsequently dried for 24 hours at 103 ° C. The coated test sample was suspended in the bath fluid and connected to the negative electrode. The bath temperature was 80 ° C, the voltage was 190 volts (less than 2 amperes of current) and the galvanization time was 4 minutes. The electrodeposited film was rinsed 74 with desiomado water, dried in the air and then cured by heating at 150 ° C overnight. A marbled yellow coating was obtained.

REFERENCE EXAMPLE 3 A test sample of carbon steel of 2 by 7 crn was coated with C-PANT in the PVB formulation as in example 2, suspended in the bath liquid and connected to the negative electrode. The bath temperature was 85 ° C, the voltage was 50 volts and the galvanization time was 1 minute.The electrodeposited film was rinsed with deionized water, air dried and then cured by heating at 150 ° C overnight. a smooth gray cover.

REFERENCE EXAMPLE 4 A carbon steel test sample of 7 by 7 c was coated with C-PANI in the PVB formulation as in example 2, suspended in the bath liquid and connected to the negative electrode. The bath temperature was 85 ° C, the voltage was 190 volts and the galvanization time was 4 minutes. The electrodeposited film was rinsed with deionized water, air dried and then cured by heating at 150 ° C overnight. The resulting coating had a rough surface.

REFERENCE EXAMPLE 5 A 2 by 7 cm carbon steel sample was coated with C-PAMT in the PVB formulation as in Example 2, suspended in the bath liquid and connected to the negative electrode. The bath temperature was 85 ° C, the voltage was 100 volts and the galvanization time was 1 minute. The electrodeposited film was rinsed with deionized water, air dried and then cured by heating at 150 ° C overnight. A smooth gray coating was obtained.

REFERENCE EXAMPLE 6 A 2 by 7 cm microscope slide was coated with the monophilic acid salt of polliniaphine (PONDO) and dried. PANDA was prepared by an emulsion polymerization process as in Example 1 of the US patent. A. No. 5,457,167. The pad with PANDO coating was suspended in the bath fluid and connected to the negative electrode. The temperature of the bath was 85 ° C, the voltage of 200 volts and galvanization time of 4 minutes. The electrodeposited film was rinsed with distilled water, dried in the air and then cured by heating at 150 ° C for 30 minutes. A gray coating was formed on the PANDO.

REFERENCE EXAMPLE 7 A sample for carbon steel test of 2 by 7 crn was coated with C-PONI in the PVB formulation as in example 2, suspended in the bath liquid and connected to the negative electrode. The bath temperature was 30 ° C, the voltage was 100 volts and the galvanization time was 7 minutes. The electrodeposited film was rinsed with deionized water, dried in air and then cured by heating at 150 ° C for 30 minutes. A smooth gray coating was obtained with certain areas not coated on the edges.REFERENCE EXAMPLE 8 A 2 by 7 cm aluminum plate was coated with C-PONI in the PVB formulation as in example 2, the bath liquid was suspended and connected to the negative electrode. The bath temperature was 30 ° C, the voltage was 200 volts and the galvanization time was 4 minutes. The electrodeposited film thus formed showed the formation of ampules during the coating process. This electrodeposition was repeated with a galvanization time of 1 minute and 200 volts, as well as a galvanization time of 4 minutes and 100 volts, and once again ampules were produced, as well as microscopic craters. Finally, an aluminum plate was coated with the PVB formulation without C-PONI and a galvanization time of 1 minute and 100 volts was used. There was a very light coating that looked like paint splashed on the microscope.

REFERENCE EXAMPLE 9 An ur-ethane primer system was used to apply an electrically conductive film to the surface of a substrate prior to the electrodeposition of the coating. The urethane primer was prepared in a couple composition A comprising Desmophen 680-70 with an equivalent hydroxide weight of 740 (Miles Laboratories), 74.0 grams; acetate "le butyl, 33.8 grams; xylene, 26.6 grams; and methyl isobutyl ketone (MIBK), 41.2 grams. The composition of part B comprised Desmodur Z-4370 with an equivalent weight of NCO of 365 (Miles Laboratories), 40.2; and butyl acetate, 10.0 grams. The p-toluene sulphonic acid polyamide salt (0.2 grams) was added to a solution containing 3.5 grams of part A and 1.0 grams of part B. The polyanil a salt did not disperse in the solution. The polyanilma salt of the dinomlnaphthi lenosulphonic acid (PANDA) (0.5 grams) prepared by the emulsion polymerization process of example 1 in copending application Serial No. 08 / 355,143, was added to 3.5 grams of the part A and 1.0 grams of part B. A green solution easily formed indicating that the polyaniline salt did not deprotonate. This solution was applied to an anodized aluminum panol using an air brush. The film was dried at 100 ° C overnight. A 2 by 7 crn panel coated with PANDO in poly urethane primer as described above was electrocoated. The bath temperature was 30 ° C, the galvanization time 5 minutes and the voltage 300 volts. There was a good electrorevesence near the lower part of the panel. Films electrodeposited on an aluminum plate or on a glass microscope slide, both of which were coated with the PONDO on the urethane primer, were non-conductive using a normal multirnetro (resistance of more than 30 seconds).

REFERENCE EXAMPLE 10 This example illustrates the preparation of electrodeposited coatings containing polyaniline and the measurement of electrical and color conductivity, with and without impurification of the elect coating surrounded with an organic acid. A bath resin of elect surround was prepared as indicated in Examples 1-9 by combining 102.3 grams of CATHOGUORD emulsion, 23.9 grams of CATHOGUARD * paste and 124.2 grams of deionized water. The mixture was subsequently poured through a 35 micron filter bag (type BMNO 35, Filter Specialists, Tnc, 100 Anchor Road, Michigan City, IN) into a 400 ml flask on a thermostatically controlled hot plate with stirrer. . A stainless steel mesh served as a node. An aluminum plate of 2.54 crn by 7.62 c was elect r-ogalvanizo at a bath temperature of about 29 ° C and at 190 volts for 4 minutes. The film was rinsed with deionized water, dried by blowing nitrogen and cured at 150 ° C for 1 hour. The coating was smooth, even and of a light gray color. Polymeric salt of polyaniline and p-toluene sulfonic acid (PANI-PTSA) was prepared by an aqueous solution polymerization. Aniline was added, 16.7 grams (0.18 moles) and p-toluene sulfonic acid, 57.3 grams (0.3 mole) to 590 ml of water in a covered and stirred reactor maintained at 5 ° C and covered with nitrogen. Ammonium peroxide (51.1 grams in 120 ml of water) was added dropwise over a period of 50 minutes. The mixture was stirred for 22 hours, during which time a dark green precipitate formed. The precipitate was washed with 2 liters of a 10% solution of p-toluene sulfonic acid in water followed by 1 liter of isopropanol. After removing with air the polymer production was 70 grams. Five grams of PAN1-PTS0 were added to the composition of the electrodeposition bath and mixed for approximately 1 hour. An aluminum plate of 2.54 by 7.62 cm was electrodeposited in this composition at a bath temperature of about 29 ° C and 190 volts for 4 minutes. The film was rinsed with deeionized water, air dried with nitrogen and cured at 150 ° C for 30 minutes. The coating was smooth, even and of a dark gray-blue color. The composition of the bath was mixed for 3 days to ensure complete dispersion of the polyamide and electrodeposition was carried out as above. Another aluminum plate was electrogalvanized in the composition of the elect surrounding bath containing PANF-PTSO. After deposition, the film was carefully rinsed for approximately n minute with 0.5 M camphor sulfonic acid (CSO) instead of deionized water, dried by blowing nitrogen and cured at 150 ° C for 30 minutes. The coating was smooth, even and olive-brownish green. The conductivity of the resulting films was measured using a normal nmrimeter in which the probes were placed about 1 cm apart. The results in table 1 show that the composition of the electrostructure prepared from the CATHOGUARD * produced a film that was non-conductive as well as the film that issues PONI-PTSA added to the composition with 3 days of mixing . In contrast, the coating formed from the composition containing PRNT-PTSO and subsequently washed with CSO showed a conductivity of more than three orders of magnitude.

TABLE 1 In order to relate the color of the film to electrical conductivity, a HunterLabs Ultrascan was used to quantify the reflectance on a rectangular coordinate system L *, a *, b *. The coordinate axis L * is measured without luminosity on a continuum of luminosity in darkness; the a * axis is a measure on a continuum from green (minus) to red (plus); and the b * axis is measured from a continuum from blue (minus) to yellow (plus). (See Uest, B., Plastics Engmeermg pp. 37-39, January 1987). Table 2 shows that the impurification of the film with CSO causes a displacement in the axis a * towards a green color (increasing the least) and outside a red color (more) and a displacement in the b * axis towards a yellow (more) and out of a blue color (less).

TABLE 2 In this way, the lining containing polya line and that was rinsed with OSA showed a marked increase in conductivity, as well as a change in color distmto.

EXAMPLE 11 This example illustrates the impurification of the surrounding elect liner by irradiation in a bath containing an organic acid. In an initial test of this method, the film was immersed in a bath containing 0.5 M CSA immediately after preparation. The result was that the emulsion that adhered to the coating gelled on contact with the acid and became difficult to rinse. In subsequent preparations, the electrodeposited film was first rinsed with deionized water and then impregnated in an irresolution bath containing acid. Aluminum plates of 2.54 x 7.62 crn were electrodeposited in the bath containing the CATHOGUARD, mixed with PANI-PTSfl at 34 ° C or 36 ° C for 4 minutes and at 190 V. After a rinse with distilled water, the film was impregnated for 2 minutes in 0.5 M p-toluene sulphonic acid, dried by blowing nitrogen and cured at 150 ° C for 30 minutes.

EXAMPLE 12 This example illustrates the preparation of a base coat and an overcoat by elect cathodic sputtering. A 7.54 cm and 7.62 cm aluminum plate was electrodeposited with the composition of Example 10 consisting of COTHOGUORD® mixed with PANI-PTSA. Electrodeposition was at 34 ° C for 4 minutes and 190 V. The basecoat film was rinsed with distilled water and impregnated for 2 minutes in a bath containing 0.5M p-toluene sulfonic acid. The film was subsequently dried by blowing nitrogen and cured at 150 ° C for 30 minutes. An overcoat was then electrodeposited in the bath containing the CATHOGUARD®, mixed with PANI-PTSA at 36 ° C for 6 minutes at 250 V. The film on the overcoat was rinsed with deionized water, dried by blowing nitrogen and cured at 150 ° C. ° C for 30 minutes. A second aluminum plate of 2.54 cm x 7.62 c was electrodeposited in the bath containing the CATHOGUARD® mixed with PANI-PTSA at 36 ° C for 4 minutes and 10 V. After a rinse with deionized water, the coating film The base was impregnated for 2 minutes in 0.5 M p-toluene sulfonic acid, dried by blowing nitrogen and cured at 150 ° C for 30 minutes. An overcoat was electrodeposited in the bath containing the CATHOGUARD® mixed with PANI-PTSA at 32 ° C for 4 minutes at 190 V. The film was rinsed with distilled water, dried by blowing nitrogen and cured at 150 ° C for 30 minutes. minutes A third coated aluminum plate was prepared by repeating the above method at a temperature of 34 ° C to electrodeposite the base coat and at a temperature of 36 ° C to electrodeposite the overcoat.

EXAMPLE 13 This example illustrates the thickness of the surrounding elect coverings. A digital coating thickness gauge Elcometer model 3 5NT was used to measure the thickness of several electrodeposited surfaces deposited on aluminum plates of .5 cm x 7.62 crn. The compositions of the crossover were either COTHOGUORDR as in Examples 1-9, or CATHOGUARD® mixed with 5 grams of PANI-PTSO, as in example 10. Mixing of the CATHOGUARD® mixed with polyalpha salt was done over a period of 9 days or more. The time of elec enclosure was 4 minutes and the bath temperature 30 ° C. The voltage was 190 V except for two ba or voltage coating preparations in which the voltage used was 50 or 20 volts. The doped coatings were prepared as in Example 11, by impregnating the electrodeposited coatings in 0.5 M p-toluene sulfonic acid (impregnated with PTSA) and curing them. All measurements were made after cure the reverses. At least 12 thickness measurements were made at several points on each sample to obtain an average value pair-to-each coating. The average value for each of the coating samples was grouped with values of coating samples prepared from the same electrodeposition composition and the same or different experimental conditions (Table 3). Means were calculated for each group of samples and reported in Table 3. In two initial preparations, a mixture of one hour of the electrodeposition resin composition was used and coatings of 25μ and 29u thickness were obtained.

Subsequently, the mixing lasted 9 days or more to achieve complete mixing. Substantially thicker coatings were obtained, suggesting that mixing was incomplete after only one hour so that longer mixing times were required (see Table 3). In the preparation of multilayer coatings with top and base coatings, the first preparation (thickness of 80u in Table 3) was made by depositing the base at 36 ° C and the overcoat at 32 ° C and the second preparation (thickness of rain in table 3) was prepared by depositing the base at 34 ° C and the reverse envelope at 36 ° C (see example 12). As shown in Table 3, thicker coatings were obtained with the resin composition of POMT-PTSfl mixed with CATHOGUORDR compared with that of the COTHOGUORDR alone. The impregnation with PTSO seemed to shrink the coatings as also the coatings treated with the impregnation with PTSO to make them conductors showed a decrease in thickness compared with the coatings that were not treated with the impregnation with PTSO. Reduced voltage levels of 50 and 20 volts for 4 minutes showed producing coatings from the CATHOGUARD® resin composition mixed with PANI-PTSA. The thickness of the coating obtained with this mixture at reduced voltage levels was comparable with the thickness obtained with the CATHOGUORDR only at 190 V.

The basecoat and the overcoat were produced as in example 12, electroplating a basecoat on an aluminum plate, rinsing with deionized water and impregnating in a bath containing PTSA, curing, electroplating an overcoat, rinsing with deionized water and curing. Coatings of substantially greater thicknesses were obtained by this method and were obtained with the deposition of a single layer coating (see Table 3).

TABLE 3 to. Voltage = 50 V b. Voltage --- 20 V In view of the above, it will be noted that the different objects of the invention and other successful results are obtained.

Claims (19)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for forming coating on an electrically conductive surface comprising the steps of: (a) immersing said electrically conductive surface in an aqueous bath comprising an electable mixture of intrinsically insulating ion polymer (IIP) and naphtha organic acid salt of an intrinsically conductive polymer (ICP); (b) applying a voltage between an electrode and said surface in the bath to deposit a non-conductive polypept coating of said mixture on said surface, wherein said voltage is applied so that said surface is negatively charged; and (c) curing said polymer coating.

2. A method according to claim 1, wherein the ICP is selected from the group consisting of polyanil, polypyrrole and polythiophene.

3. A method according to claim 2, wherein the organic acid is a sulfonic acid, an organic acid containing phosphorus, a carboxylic acid or mixtures thereof.

4. A method according to claim 2, wherein said ICP is polyamide.

5. A method according to claim 4, wherein the organic acid is a sulfonic acid.

6. - A method according to claim 2, wherein said IIP is selected from the group q? E consisting of epoxy resins, polyurethanes, arni noplastic resins and acrylic resins.

7. A method according to claim 6, wherein said IIP is an epoxy resin and a thermally activatable interlacing agent.

8. A method according to claim 1, wherein the voltage is less than 75 volts.

9. A method according to claim 1, wherein after said deposition of the polyrnical coating and before said curing, the method further comprises immersing the polyrnomeric coating in an organic acid to provide an electrically conductive polymeric coating.

10. A method of compliance with the claim 9, further comprising the step of: (d) electrodeposing one or more subsequent polymer coatings onto said electrically conductive polymer coating.

11. A method according to claim 10, wherein said subsequent polymer coatings comprise an IIP, an ICP or a mixture thereof.

12. A method according to claim 11, wherein said subsequent polymer coatings comprise an IIP selected from the group consisting of epoxy resins, polyurethanes, aminoplast reams and acrylic resins.

13. - A method according to claim 11, wherein said electrodepositable organic resin comprises a mixture of an organic salt of an ICP selected from the group consisting of pol aniline, polypyrrole and polythiophene and an IIP selected from the group consisting of of epoxy reams, polyurethanes, aminoplastic resins and acrylic resins.

14. A method according to claim 11, wherein said coating has a thickness of more than 60 microns.

15. A composition for forming a coating in an electrodeposition process comprising water and an electrodepositable mixture of an IIP and an ICP.

16. A composition according to claim 15 wherein said ICP is polylamino, polypyrrole or polythiophene.

17. A composition according to claim 16, wherein said organic acid is a sulfonic acid, a phosphonic acid, a carboxylic acid or a mixture thereof.

18. A composition according to claim 15, wherein said TTP is selected from the group consisting of non-toxic resins, polyesters, acrylic resins and acrylic resins.

19. A composition according to claim 15, wherein said electrodepositable mixture comprises polyaniline, epoxy resin and a thermally activatable interlacing agent.