US3663402A - Pretreating electrodepositable compositions - Google Patents

Pretreating electrodepositable compositions Download PDF

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US3663402A
US3663402A US88533A US3663402DA US3663402A US 3663402 A US3663402 A US 3663402A US 88533 A US88533 A US 88533A US 3663402D A US3663402D A US 3663402DA US 3663402 A US3663402 A US 3663402A
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ultrafiltration
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resin
solubilized
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Roger M Christenson
Robert R Zwack
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PPG Industries Inc
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D13/00—Electrophoretic coating characterised by the process
    • C25D13/22—Servicing or operating apparatus or multistep processes
    • C25D13/24—Regeneration of process liquids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D13/00—Electrophoretic coating characterised by the process
    • C25D13/22—Servicing or operating apparatus or multistep processes

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  • Williams Attorney-Chisholm & Spencer A method of pretreating electrodepositable compositions prior to utilization of such compositions, in an electrodeposition process, which comprises subjecting a synthetic resin ionically solubilized in an aqueous medium to a selective separation process such as ultrafiltration which passes an aqueous effluent through a physical barrier while retaining the solubilized resin component.
  • the method enables the removal of deleterious impurities and contaminants which affect coating parameters and thus provides a direct method of controlling the quality of the deposited film.
  • Electrophoretically applied coating compositions are particularly useful when the articles to be coated are of complex and unusual designs since the structural configuration is ordinarily of little or no significance when coating by this process. Film compositions applied by electrodeposition do not run, drip, sag, or wash off during baking. Virtually any electrically conductive surface may be coated by electrodeposition.
  • Treated and untreated metals such as iron, steel, copper, zinc, brass, tin, nickel, chromium and aluminum are among the most commonly employed substrates.
  • Paper or other non-conductive materials coated or impregnated with substances to render them conductive under conditions of the coating may also be employed as coating substrates.
  • the articles to be coated are immersed in an aqueous dispersion of a solubilized, ionized, film-forming material, such as a synthetic organic vehicle resin.
  • a solubilized, ionized, film-forming material such as a synthetic organic vehicle resin.
  • the article to be coated serves as an electrode through which an electric current passes to a counter-electrode, causing the migration and the deposition of the vehicle resin on the charged article.
  • the articles containing the deposited films are then withdrawn from the electrodeposition bath, usually rinsed and then baked in the manner of a conventional finish.
  • Another source of contamination is the atmospheric air over the electrodeposition bath, for upon exposure to air, CO is absorbed into the aqueous bath composition.
  • the dissolved CO is ordinarily present in the electrodeposition bath in the form of carbonates.
  • Contamination of depositable compositions may be derived from various sources, for example, from the manufacturing equipment; from the raw materials employed in formulating the compositions, such as pigments and deionized water; unreacted acids and monomers; free maleic anhydride, acrylic acid or oxidized formaldehyde; and from the atmosphere over the manufacturing container, whereby the composition may absorb carbon dioxide which exists, for the most part, in the composition in the form of carbonates; chloride ions which may also be absorbed from the atmosphere if the composition is exposed to testing equipment which releases salt spray vapors into the air, or from low purity deionized water. All have a deleterious effect on bath operating parameters and physical and chemical characteristics of the deposited film. For example, rupture voltage decreases, throw power decreases, conductivity of the bath increases, and the chemical resistance of the cured film decreases.
  • low molecular weight resin residues such as maleinized fatty acid residues, and the like
  • Some pigments have introduced water-soluble chromates and phosphates into the bath which likewise have deleterious effect because they tend to accumulate in the bath.
  • the solvent and solubilizing agent concentration can be controlled by subjecting feed composition to such a selective separation process.
  • Various other ions, solvents, components, ingredients, and the like may be removed from the feed compositions or controlled to the extent necessary to produce the desired product.
  • the present process also provides a method of concentrating low solids feed compositions, thereby aiding in control of the electrodeposition bath composition.
  • the selective filtration process employed in the process of the instant invention is any process such as ultrafiltration which separates water from the electrodeposition feed stock through a physical barrier while retaining the solubilized resin components.
  • any means may be utilized which accomplishes this purpose.
  • Such a filter or barrier will pass not only water, but also solute of substantially lower molecular weight than the vehicle resin such as excess amine carbonates, low molecular weight solvent and simple organic or inorganic anions and cations which may be present in the feed composition.
  • means for accomplishing this separation are reverse osmosis, where water of high purity may be obtained, and ultrafiltration, as well as other means which accomplish the intended result. Because ultrafiltration is particularly useful in controlling or removing contaminants from feed stock compositions, or other depositable compositions prior to utilization, ultrafiltration is especially preferred.
  • the ultrafiltration process separates materials below a given molecular weight size from the composition. With the proper selection of membranes, the treatment does not remove any product or desirable resin from the feed stock composition,
  • Ultrafiltration may be defined as a method of concentrating solute while removing solvent, or selectively removing solvent and low molecular weight solute from a significantly higher molecular weight solute. From another aspect, it is a process of separation whereby a solution containing a solute of molecular dimensions significantly greater than the solvent is depleted of solute by being forced under a hydraulic pressure gradient to flow through a suitable membrane.
  • the first definition is the one which most fittingly describes the term ultrafiltration as applied to an electrodeposition bath.
  • Ultrafiltration thus encompasses all membrane-moderated, pressure-activated separations wherein solvent or solvent and smaller molecules are separated from modest molecular weight macromolecules and colloids.
  • the term ultrafiltration is generally broadly limited to describing separations involving solutes of molecular dimensions below the limit of resolution of the optical microscope, that is, about 0.5 micron.
  • the basic ultrafiltration process is relatively simple. Solution to be ultrafiltered is confined under pressure, utilizing, for example, either a compressed gas or liquid pump in a cell, in contact with an appropriate filtration membrane supported on a porous support. Any membrane or filter having chemical integrity to the system being separated and having the desired separation characteristic may be employed. Preferably, the contents of the cell should be subjected to at least moderate agitation to avoid accumulation of the retained solute on the membrane surface with the attendant binding of the membrane. Ultrafiltration is continually produced and collected until the retained solute concentration in the cell solution reaches the desired level, or the desired amount of solvent or solvent plus dissolved low molecular weight solute is removed. A suitable apparatus for conducting ultrafiltration is described in U.S. Pat. No. 3,494,465, which is hereby incorporated by reference.
  • ultrafiltration membrane There are two types of ultrafiltration membrane.
  • One is the microporous ultrafilter, which is a filter in the traditional sense, that is, a rigid, highly voided structure containing interconnected random pores of extremely small average size.
  • solvent in the case of electrodeposition, water
  • the flow rate proportional to the pressure difi'erence, while dissolved solutes, to the extent that their hydrated molecule dimensions are smaller than the smallest pores within the structure, will pass through, little impeded by the matrix. Larger size molecules, on the other hand, will become trapped therein or upon the external surface of the membrane and will thereby be retained.
  • microporous ultrafilters are inherently susceptible to internal plugging or fouling by solute molecules whose dimensions lie within the pore size distribution of the filter, it is preferred to employ for a specific solute a microporous ultrafilter whose mean pore size is significantly smaller than the dimensions of the solute particle being retained.
  • the diffusive ultrafilter is a gel membrane through which both solvent and solutes are transported by molecular diffusion under the action of a concentration or activity gradient. in such a structure, solute and solvent migration occurs via random thermal movements of molecules within and between the chain segments comprising the polymer network.
  • Membranes prepared from highly hydrophilic polymers which swell to eliminate standard water are the most useful difiusive aqueous ultrafiltration membrane. Since a diffusive aqueous ultrafilter contains no pores in the conventional sense and since concentration within the membrane of any solute retained by the membrane is low and timeindeper dent, such a filter is not plugged by retained solute, that is, there is no decline in solvent permeability with time at a constant pressure. This property is particularly important for a continuous concentration or separation operation. Both types of filters are known in the art.
  • the presently preferred ultrafilter is an anisotropic membrane structure such as illustrated in FIG. 1.
  • This structure consists of an extremely thin, about l/ 10 to about 10 microns, layer of a homogeneous polymer 1 supported upon a thicker layer of a microporous open-celled sponge 2, that is, a layer of about 20 microns to about 1 millimeter, although this dimension is not critical.
  • this membrane can be further supported by a fibrous sheet, for example, paper, to provide greater strength and durability.
  • These membranes are used with a thin film or skin side exposed to the high pressure solution. The support provided to the skin by the spongy substrate is adequate to prevent film rupture.
  • Membranes useful in the process are items of commerce and can be obtained by several methods.
  • One general method is described in Belgian Pat. No. 721,058.
  • This patent describes a process which, in summary, comprises (a) forming a casting dope of the polymer in an organic solvent, (b) forming a film of the casting dope, and (c) preferentially contacting one side of said film with a diluent having high compatibility with the casting dope to effect precipitation of the polymer immediately upon coating the cast film with the diluent.
  • Membranes can be typically prepared from thermoplastic polymers such as polyvinyl chloride, polyaerylonitrile, polysulfones, poly( methyl methacrylate), polycarbonates, poly( n-butyl methacrylate), as well as a large group of copolymers formed from any of the monomeric units of the above polymers, including Polymer 360, a polysulfone copolymer.
  • thermoplastic polymers such as polyvinyl chloride, polyaerylonitrile, polysulfones, poly( methyl methacrylate), polycarbonates, poly( n-butyl methacrylate), as well as a large group of copolymers formed from any of the monomeric units of the above polymers, including Polymer 360, a polysulfone copolymer.
  • anisotropic membranes operable in the process of the invention include: Diaflow membrane ultrafilter PM-30, the membrane chemical composition of which is a polysulfone copolymer, Polymer 360, and which has the following permeability characteristics:
  • the membrane is chemically resistant to acids (HCl, H H PO all concentrates), alkalis, high phosphate buffer and solutions of common salts as well as concentrated urea and quanadine hydrochloride.
  • the membrane is solvent-resistant to alcohol, acetone and dioxane.
  • the membrane is not solvent-resistant to dimethylformamide or dimethyl sulfoxide. This membrane is hereinafter referred to as Membrane A.
  • Dorr-Oliver XPA membrane the membrane chemical composition of which is Dynel (an acrylonitrile-vinyl chloride copolymer) and which has the following permeability charac teristics:
  • Membrane B Flux Molecular Reten- (gal./sq.ft./day at Solute Weight tion 30 psi, 1.0% solute) Cytochrome C 12,000 50 100 a Chymotrypsinagen 24,000 90 22 Ovalbumin 45,000 100 45 This membrane is hereinafter referred to as Membrane B.
  • the microporous ultrafilters are generally isotropic structures, thus flow and retention properties are independent of flow direction. It is preferred to use an ultrafilter which is anisotropic in its microporous membrane structure, FIG. 2. In such a membrane, the pore size increases rapidly from one face to the other. When the fine-textured side 4 is used in contact with the feed solution, this filter is less susceptible to plugging since a particle which penetrates the topmost layer cannot become trapped in the membrane because of the larger pore size 5 in the substrate.
  • the process of the invention may be operated as either a batch or a continuous process.
  • batch selective filtration or batch ultrafiltration a finite amount of material is placed in a cell which is pressurized. A solvent and lower molecular weight solutes are passed through the membrane. Agitation is provided by a stirrer, for example, a magnetic stirrer. Obviously, this system is best used for small batches of material.
  • a continuous selective filtration process is preferred. Using this technique, material is continuously recirculated under pressure against a membrane or series of membranes through interconnecting flow channels, for example, spiral flow channels.
  • the ultrafiltration process may be conducted as either a concentration process or a diafiltration process.
  • Concentration involves removing solvent and low molecular weight solute from an increasingly concentrated retentate. F iltration flow rate will decrease as the viscosity of the concentrate increases.
  • Diafiltration is a constant volume process whereby the starting material is connected to a reservoir of pure solvent, both of which are placed under pressure simultaneously. Once filtration begins, the pressure source is shut off in the filtration cell and, thus, as the filtrate is removed, an equal volume of new solvent is introduced into the filtration cell to maintain the pressure balance.
  • C is the initial solute concentration
  • C is the final solute concentration of the retentate
  • V is the volume of solute delivered to the cell (or the volume of the filtrate collected)
  • V is the initial solution volume (which remains constant).
  • Electrodepositable compositions while referred to as solubilized,” in fact are considered a complex solution, dispersion or suspension, or combination of one or more of these classes in water, which acts as an electrolyte under the influence of an electric current. While, no doubt in some circumstances the vehicle resin is in solution, it is clear that in some instances and perhaps in most the vehicle resin is a dispersion which may be called a molecular dispersion of molecular size between a colloidal suspension and a true solution.
  • the typical industrial electrodepositable composition also contains pigments, crosslinking resins and other adjuvants which are frequently combined with the vehicle resin in a chemical and a physical relationship.
  • the pigments are usually ground in a resin medium and are thus wetted with the vehicle resin.
  • an electrodepositable composition is complex in terms of the freedom or availability with respect to removal of a component or in terms of the apparent molecular size of a given vehicle component.
  • ultrafiltration comprises subjecting an electrodepositable composition to a selective separation process before it has been employed in a coating process.
  • Such compositions are usually rich in contaminants from the air, manufacturing equipment, raw materials and the like.
  • an ultrafilter preferably a diffusive membrane ultrafilter, is selected to retain the solubilized vehicle resin while passing water and low molecular weight solute, especially those with a molecular weight below about 1,000 and preferably below about 500.
  • the filters discriminate as to molecular size rather than actual molecular weight, thus these molecular weights merely establish an order of magnitude rather than a distinct molecular weight cut-off.
  • the retained solutes may, in fact, be colloidal dispersions or molecular dispersions rather than true solutes.
  • a portion of the electrodepositable composition may be continuously or intermittently removed and passed under pressure created by a pressurized gas or by means of pressure applied to the contained fluid in contact with the ultrafilter.
  • the egress side of the filter may be maintained at a reduced pressure to create thepressure difference.
  • the pressures necessary are not severe.
  • the maximum pressure in part, depends on the strength of the filter.
  • the minimum pressure is that pressure required to force water and low molecular weight solute through the filter at a measurable rate.
  • the operating pressures are between about 10 and psi, preferably between about 25 and 75 psi.
  • the ultrafilter should have an initial flux rate, measured with the composition to be treated of at least about 3 gal./sq.ft./day (24 hours), the preferred flux rate being at least about 4.5 gal./sq.ft./day.
  • the bath composition should be in motion at the face of the filter to prevent the retained solute from impeding the flow through the filter. This may be accomplished by mechanized stirring or by fluid flow with a force vector parallel to the filter surface.
  • the retained solutes comprising the vehicle resin are then employed to fill or replenish an electrodeposition bath.
  • the concentrate may be reconstituted by the addition of water either before entry to the bath or by adding water directly to the bath.
  • a number of electrodepositable resins are known and can be pretreated in accordance with this invention.
  • Virtually any water-soluble, water-dispersible or water-emulsifiable vehicle resin in an aqueous medium can be electrodeposited and, if
  • film-Forming provides coatings which may be suitable for certain purposes.
  • the present invention is applicable to any such material.
  • Electrodeposition vehicle resins are ionically solubilized, synthetic resin vehicles. Numerous such resins are described in US. Pat. Nos. 3,230,162; 3,441,489; 3,422,044; 3,403,088; 3,369,983; 3,366,563; 3,5 16,913 and 3,518,212.
  • alkyd resins include alkyd resins; modified or unmodified adducts of drying oil or semi-drying oil fatty acid esters with a dicarboxylic acid or anhydride, such as maleic anhydride adducts of linseed oil, soybean oil, or the like, modified in some cases with monomers such as styrene or a polyol; acrylic polymers, such as acid-containing interpolymers of acrylic monomers, in many cases including a hydroxyalkyl ester; mixed partial esters of fatty acids with resinous polyols, such as polyols derived from epoxy resins or sytrene-allyl alcohol copolymers; and others, including certain phenolic resins, hydrocarbon resins, etc.
  • adducts of drying oil or semi-drying oil fatty acid esters with a dicarboxylic acid or anhydride such as maleic anhydride adducts of linseed oil, soybean oil, or the like,
  • Aminoplast resins usually made from condensation of melamine, urea, benzoquanamine or the like with formaldehyde and etherified with an alcohol such as methanol, butanol, hexanol or a mixture of alcohols, are also useful, especially in combination with hydroxyl-containing alkyd or acrylic resins.
  • Inorganic bases such as metal hydroxides, especially potassium hydroxide, can be used, as can ammonia or organic bases such as amines.
  • Water-soluble amines are often preferred. Commonly used amines include ethylamine, diethylamine, triethylamine, diethanolamine, and the like.
  • base-solubilized polyacids which may be employed as electrodeposition vehicles include those taught in U.S. Pat. No. 3,392,165, wherein the acid groups rather than being solely polycarboxylic acid groups contain mineral acid groups such as phosphonic, sulfonic, sulfate and phosphate groups.
  • cationic type vehicle resins that is, vehicle resins which deposit on the cathode.
  • vehicle resins which deposit on the cathode.
  • These include polybases solubilized by means of an acid, for example, an amine-terminated polyamide or an acrylic polymer solubilized with acetic acid.
  • Other cationic polymers include reaction products of polyepoxides with amino-substituted boron esters and reaction products of polyepoxides with hydroxyl or carboxyl-containing amines; many such products are described in copending applications Ser. Nos. 772,366 (now abandoned) and 772,353, (US. Pat. No. 3,619,398) both filed Oct. 28, 1968, and Ser. Nos. 840,847 and 840,848, both filed July 10, 1969 and now both abandoned.
  • the electrodepositable composition in addition to the vehicle resin, there may be present in the electrodepositable compositions any desired pigment or pigment composition, including practically any of the conventional types of pigments employed in the art. There is often incorporated into the pigment composition a dispersing or surface-active agent. Usually the pigment or surface-active agent, if any, are ground together in a portion of the vehicle, or alone in an aqueous medium, to make a paste and this is blended with the vehicle to produce a coating composition.
  • additives to aid dispersibility, viscosity and/or film quality, such as a nonionic modifier or solvent.
  • additives such as anti-oxidants, wetting agents, anti-foaming agents, fungicides, bactericides, and the like.
  • deionized water i.e., water from which free ions have been removed by the passage through ion-exchange resins, is preferably employed.
  • the above pigments were ground in a 20 percent maleinized linseed oil solution, employing 16.5 percent diethylamine as a solubilizing agent and 1.0 percent cresylic acid as an anti-oxidant.
  • the electrodepositable composition was made from the following:
  • This composition had the following characteristics:
  • Solids Content Pigment-to- (Percent) pH Binder Ratio MEQ Solids Milliequivalems of base Of the above composition, 1,000 parts were reduced with 1,000 parts of deionized water and the reduced composition was subjected to ultrafiltration for 13 hours, utilizing "Membrane B, as hereinabove described, at 50 psi.
  • ultrafiltered paint had a rough, patchy, poor appearance. Succeeding stability tests showed numerous problems with the non-ultrafiltered paint when compared with the ultrafiltered system.
  • EXAMPLE II A white electrodepositable composition was produced utilizing the following interpolymer, resin solution and paste:
  • Interpolymer A Parts by Weight Hydroxyethyl methacrylate 8.7 Styrene 219.0 Methacrylic acid 131.0 Butyl acrylate 17.0 Di-tertiary butyl peroxide 13.2 Cumene hydroperoxide 8.8 Butyl Cellosolve 306.0
  • Resin solution B was a thin clear fluid at 30 percent solids content by weight.
  • the above composition was ground in a steel ball mill of the type utilized widely in the art to produce a Hegman grind gauge reading of 7.5.
  • the ground White Paste C had the following properties:
  • the electrodepositable composition had the following composition:
  • Pigment-to-binder ratio 0.4/1.0 pH 8.0
  • composition D was not ultrafiltered, while Composition E was treated as follows:
  • composition E To Composition E sufficient deionized water as added to reduce the solids content to about 20 percent and this composition was then subjected to ultrafiltration, utilizing Membrane B above, at 50 psi for 10 hours.
  • the collected ultrafiltrate and resulting concentrate had the following characteristics:
  • Composition D was not subjected to ultrafiltration; it was reduced to coating solids content by the addition of 2,891 parts of deionized water, and had the following characteristics:
  • Composition D and E were electrodeposited on various substrates to give a 1 mil thick film using comparable conditions, and each coating baked at 350 F. for 20 minutes. Generally, Composition E had improved gloss and smoothness when compared to Composition D.
  • Yellowness Index is measured by a spectrophotometer or with a colorometer, following ASTM Method D-1925 Test for Yellowness Index of Plastics," 1968 Book of ASTM Stendards, Part 27, and ASTM Method E-313-9, Indexes of Whiteness and Yellowness of Near- White, Opaque Materials, 1969 Book of ASTM Standards,
  • a white aqueous coating composition was produced from the above vehicle resin, using a mixed methyl and butyl ether of methylolated melamine, potassium hydroxide solubilizing agent, and titanium dioxide pigment.
  • the coating composition had the following characteristics:
  • composition F A portion of this composition (Composition F) was mixed with sufficient deionized water to reduce the solids content to about 20 percent and then subjected to ultrafiltration utilizing Membrane B at 50 psi for 8 hours.
  • the concentrate obtained is mixed as follows:
  • Deionized water 2800 Replacing components extracted by the ultrafiltration process.
  • a second portion (920 parts) of the above coating composition (Composition G) was not subjected to the ultrafiltration process and was reduced to coating solids content by the addition of 2,880 parts of deionized water.
  • Composition G had high current surges during the initial phases of the coating cycle and dropped ofi" sharply, when compared to the amperage curve of Composition F.
  • the substrates having films deposited from Composition G were completely unacceptable, as they were extremely rough, discolored and had poor chemical and physical properties; however, the films produced from Composition F (ultrafiltered) produced smooth, undiscolored films having desirable chemical and physical properties.
  • the contrast in the films was reflected in the gloss reading on the various substrates employed.
  • the Yellowness Index reading of the substrates coated with Compositions F and G showed a correlation similar to that displayed by the Yellowness Index readings of the substrates coated in Example ll with those from Composition G being substantially discolored.
  • compositions made from other vehicles for example, alkyd resins prepared from semi-drying or drying oils, esters of epoxides with fatty acids, including esters of diglycidyl ethers of polyhydric compounds, as well as other mono-, diand polyepoxides; mixed esters of a resinous polyol, such as resinous esters comprising mixed esters of an unsaturated fatty acid adduct.
  • alkyd resins prepared from semi-drying or drying oils, esters of epoxides with fatty acids, including esters of diglycidyl ethers of polyhydric compounds, as well as other mono-, diand polyepoxides; mixed esters of a resinous polyol, such as resinous esters comprising mixed esters of an unsaturated fatty acid adduct.
  • Cationic resins i.e., resins which deposit on the cathode, can also be used in substantially the same manner using known procedures.
  • aqueous potassium hydroxide solutions employed as a neutralizing agent in the above examples an readily be substituted for other metal hydroxides such as lithium or sodium hydroxide, or with an amine, preferably water-soluble, such as with isopropanolamine, triethylamine, dimethylethanolamine, or the like. Acidic solubilizing agents are employed in the case of polybasic resins.
  • the pigmentary components may be varied to produce a particular color or to impart inhibitive properties to the film.
  • Color such as cadmium yellow, cadmium red, phthalocyanine blue, chrome yellow, toluidine red, hydrated iron oxide and the like may be included if desired.
  • Other conventional type pigments employed in the art may be added, for example, iron oxide, carbon black, talc, barium sulfate and the like.
  • Such components include, for example, wetting agents, flow agents, fungicides, anti-oxidants, and the like.
  • the method of the invention is particularly applicable to the treatment of the feed composition for an operating electrodeposition bath, where such feed composition is intermittently or continuously added to the bath.
  • the feed composition can be the same as or somewhat different from the composition used to fill the bath, and when treated using a selective filtration process as described, prior to adding it to the bath, greatly reduces the control problems normally associated with operation of electrodeposition processes and maintains the improved film properties illus trated by the foregoing examples.
  • a feed composition is produced as in the above examples, ultrafiltered, and added to the bath, using known procedures, as replenishment for the coating composition removed by the coating process.
  • improvement which comprises subjecting at least a portion of the feed composition to an ultrafiltration processes wherein an ultrafiltration membrane passes water and solute of substantially lower molecular size than said resin component, while retaining said resin component, adding the ultrafiltered feed composition to the electrodeposition bath and subsequently electrodepositing a coating from the bath.
  • vehicle resin component comprises an ionically solubilized synthetic resin.
  • said synthetic resin comprises a polybasic resin solubilized with an acid.

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US4051091A (en) * 1974-11-19 1977-09-27 Mitsubishi Denki Kabushiki Kaisha Water-dispersion varnish for electrodeposition and process for making said water dispersion varnish
US4331525A (en) * 1979-11-13 1982-05-25 Diamond Shamrock Corporation Electrolytic-ultrafiltration apparatus and process for recovering solids from a liquid medium
US4639319A (en) * 1984-08-25 1987-01-27 Gerhard Collardin Gmbh Electrolyte stabilization of latices
US4661385A (en) * 1985-06-04 1987-04-28 Amchem Products, Inc. Filtration stabilization of autodeposition baths
US5569384A (en) * 1992-03-09 1996-10-29 Herberts Gmbh Process for recovering the overspray of aqueous coating agents during spray application in spray booths
US20060286693A1 (en) * 2005-06-15 2006-12-21 University Of Delaware Fabrication of three-dimensional photonic crystals in gallium arsenide-based material

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FR2387999A1 (fr) * 1977-04-22 1978-11-17 Rhone Poulenc Ind Liant pour la fabrication de revetements de sol aiguilletes
JPS63100032U (it) * 1986-12-19 1988-06-29
US11447624B2 (en) 2017-12-06 2022-09-20 Celanese International Corporation Low density foamed thermoplastic vulcanizate compositions

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US3526588A (en) * 1967-09-21 1970-09-01 Amicon Corp Macromolecular fractionation process

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GB1163351A (en) * 1967-03-22 1969-09-04 Pressed Steel Fisher Ltd Treatment of Effluents by the Reverse Osmosis Process
SE442411B (sv) * 1969-04-09 1985-12-23 Ppg Industries Inc Sett att reglera sammansettningen av ett elektrofores - eller eldopplackeringsbad
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GB1071458A (en) * 1965-05-31 1967-06-07 Pressed Steel Fisher Ltd A process for treating the effluent from plants for the electro-deposition of paint
US3526588A (en) * 1967-09-21 1970-09-01 Amicon Corp Macromolecular fractionation process

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4051091A (en) * 1974-11-19 1977-09-27 Mitsubishi Denki Kabushiki Kaisha Water-dispersion varnish for electrodeposition and process for making said water dispersion varnish
US4331525A (en) * 1979-11-13 1982-05-25 Diamond Shamrock Corporation Electrolytic-ultrafiltration apparatus and process for recovering solids from a liquid medium
US4639319A (en) * 1984-08-25 1987-01-27 Gerhard Collardin Gmbh Electrolyte stabilization of latices
US4661385A (en) * 1985-06-04 1987-04-28 Amchem Products, Inc. Filtration stabilization of autodeposition baths
US5569384A (en) * 1992-03-09 1996-10-29 Herberts Gmbh Process for recovering the overspray of aqueous coating agents during spray application in spray booths
US20060286693A1 (en) * 2005-06-15 2006-12-21 University Of Delaware Fabrication of three-dimensional photonic crystals in gallium arsenide-based material

Also Published As

Publication number Publication date
CA968743A (en) 1975-06-03
GB1373792A (en) 1974-11-13
FR2114567A5 (it) 1972-06-30
DE2156180B2 (de) 1974-07-18
IT945790B (it) 1973-05-10
DE2156180A1 (de) 1972-05-31
JPS5510674B1 (it) 1980-03-18

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