Abstract: A liquid coating nozzle is provided with a first block which has an inner liquid reserving section that extends in the longitudinal direction and an inner discharge section which includes a plurality of small holes formed in the longitudinal direction at a bottom portion of the liquid reserving section. The nozzle is also provided with a second block which has an inner space defining a gas reserving section that extends in the longitudinal direction outside the first block and an outer discharge section formed in the longitudinal direction at a bottom portion of the inner space. The outer discharge section includes a plurality of small holes and produces a gas flow that externally surrounds a linear or curtain-shaped liquid flow that flows downward from the small holes. This results in the formation of a thin coating film in a short time and reduces the consumption of liquid and coating nonuniformities.

Abstract: The subject of the invention is a process for manufacturing a glass strand mat, in which a binder is deposited continuously on a wad of glass strands. The strands are distributed on a moving conveyor, and then the wad is subjected to an oven treatment and possibly to calendering. The process consists of depositing on the wad of strands a liquid binder whose viscosity during deposition is less than approximately 40 millipascal seconds, the binder being formed by an aqueous solution of polyvinyl alcohol(s).

Abstract: A slide bead coating method and apparatus which is able to form a stable bead over the width of coating solutions and regularly coat the coating solutions on a web to an edge region and which is able to change the width of the coating solutions without stopping the coating operation even if the width of the web changes. A discharged liquid from a nozzle is applied on both side edges of the coating solutions flowing down a slide surface. Thereby, the stable bead can be formed at the side edges of the coating solutions, so that the coating solutions can be coated on the web to the edge region. Edge bead is formed at both side edges of the coating solutions through the nozzle, so that the width of the coating solutions can be adjusted.

Abstract: A method for minimizing coating defects caused by strikethrough when simultaneously slide coating a first fluid layer, a second fluid layer, and a third fluid layer. The method includes preparing the first, second, and third fluids such that the first solute is incompatible with the second and third solutes and such that the first fluid minimizes strikethrough of at least one of the second and third fluids to a slide surface when the first fluid is positioned between the slide surface and the second and third fluids. The present invention is useful in preparing imaging, data storage, and other media.

Abstract: The method is related to intermittent coating capable of distinctly defining a boundary between a coated region and an uncoated region on a web, to thereby intermittently form a coated film on the web with increased accuracy and efficiency. A coating liquid feed pump is arranged so as to alternately communicate with a circulation line and a pocket of an extrusion type coater through a directional control valve, resulting in coating liquid being intermittently fed to the pocket and then forced out of a slit, so that coated regions and uncoated regions may be alternately formed on a conductive sheet material. During interruption of communication between the pocket and the feed pump, the pocket is permitted to communicate via a discharge pipe and a shut-off valve with a sub-tank to reduce a pressure of coating liquid in the pocket, to thereby prevent undesired feeding of coating liquid to the uncoated region beyond an end position of the coated region.

Abstract: A method and apparatus for preventing vortical air flow behind a free-falling curtain in a curtain coating apparatus. There is a critical region within the coating apparatus defined in part by a coating hopper, the free-falling curtain delivered from the coating hopper, a portion of the moving substrate supported on a roller to which the free-falling curtain is delivered, and an air shield located between the roller and the coating hopper. A first intake slot proximate to the moving substrate shield is used to remove boundary-layer air entrained on the moving substrate. A second intake slot positioned within the critical region is used to remove boundary-layer air entrained on the free-falling curtain. Each of the two intake slots is connected to vacuum source. One or two vacuum sources may be used.

Abstract: A process for the production of a material for sealing and healing wounds comprises the even application of a suspension to a collagen carrier. An elongated container, into which the suspension is filled, is provided with a base frame (1) and a set of two perforated plates (2,3) as its bottom. The upper plate (3) is movable and is continuously moved back and forth during the process at a right angle to the transport direction of the collagen carrier, which allows the suspension to drip on the collagen carrier which is transported underneath the container.

Abstract: A silicon dioxide containing coating can be used for multi-layer hermetic coatings, interlayer dielectric coatings, and flat panel display coatings. The coating is formed by applying a coating composition comprising polysilastyrene to a substrate and heating the polysilastyrene in an oxidizing atmosphere.

Abstract: A method of modulating coating patterns is disclosed. The method uses the steps of dispensing a composite comprising a carrier fluid layer and a transferring the composite to the substrate, wherein interfacial interaction among the carrier fluid layer, the functional fluid layer, and the substrate generates a patterned coating of the functional layer on the substrate. The coating patterns provide controlled release surfaces for tapes, image receptors, and the like.

Abstract: In a process for the coating of boards (4) with a poured material (L), especially for the coating of printed circuit boards with, for example, solder resist, the boards (4) to be coated are transported through and beneath a curtain of poured material descending transversely to the transport direction and the poured material descending in the form of a pouring curtain (LV) thus falls onto the boards (4). The descending pouring curtain (LV) falls onto a planar deflector surface (20) before falling onto the board (4), with an acute angle (.alpha.) being formed between the deflector surface (20) and the plane of the pouring curtain (LV), which deflector surface (20) has a cut-off edge (21) at its lower end. After falling onto the deflector surface (20), the poured material runs along that deflector surface (20) downwards towards the cut-off edge (21) and then descends onto the board (4).

Abstract: Non-uniform liquid flows in the curtain limit the process speed and cause defects during coating. These liquid streams are equalized by auxiliary liquids in the curtain holder. If the curtain edge is separated by a free jet of a separating liquid, turbulence in the curtain edge is isolated from the curtain center. The maximum attainable speed is increased. Because the free jet also removes liquid from the curtain in the penetration area, a beaded edge is not generated on the base, and it is possible to coat uniformly thick to the outer edge of the base. The process is especially suitable for making photographic films.

Abstract: The present invention aims to form a thin coating film of even thickness within a short processing time under a curtailed consumption of coating liquid; where, a gas is spouted from nozzle 4 disposed facing to protection glass 2 of cathode ray tube, and a liquid containing fluorescent material is made to spout accompanied by the spouting gas, to be applied on protection glass 2 by shifting the positioning of protection glass 2 relative to nozzle 4 while spouting the liquid containing fluorescent material.

Abstract: A method for producing a light-sensitive material. The method includes the steps of: discharging coating solution, including the light-sensitive material, from a coater die; forming a curtain layer of coating solution by causing the coating solution to fall from a die lip of the coater die in which the curtain layer is formed with an edge guide in which an end of the edge guide is arranged in the vicinity of the die lip and the other end of the edge guide is inclined toward the coater die in relation to the vertical line from the die lip; and coating a support with the coating solution by conveying the support at the downstream end of the curtain layer.

Abstract: An apparatus for coating surfaces consists of a basin, open to the atmosphere, divided into two channels by a wall running perpendicular to the coating direction. Liquid is supplied to the primary channel, the channel farther from the curtain. A continuous, adjustable gap between the dividing wall and the bottom of the basin offers resistance to flow but passes the coating composition from the primary to the secondary channel. The secondary channel has an edge that is horizontal and relatively low so that the coating composition overflows it to form a free-falling curtain. The dividing wall, by providing flow resistance, assists in distributing the supplied coating composition along the length of the primary channel, and reduces any flow disturbances caused by the entering coating composition. The secondary channel promotes additional evening of the flow distribution before the curtain forms.

Abstract: A curtain coating apparatus and method in which a catch pan is disposed between a curtain head and a web. The catch pan includes a receiver part used when a curtain film liquid is not coated, an upright level difference part and a shelf part having a slope in the direction of the level difference part. The catch pan is moved in the web running direction or in the opposite direction. The curtain film is received in the receiver part after stopping the coating or before starting the coating, and the tip of the shelf part is moved backward or forward from the curtain film in starting or stopping respectively, whereby an excess coated part is not produced when starting and stopping the coating.

Abstract: Method and apparatus are described for setting liquid photographic materials which have been applied as a coating on a support web, while the coated web is moving substantially horizontally with the liquid materials on the underside of the web. Chilling of the liquid materials may be commenced while the web is moving upwards or downwards after coating, but any setting is not permitted to occur until the web has been turned to move substantially horizontally with the liquid materials on the underside. In this way, gravity and surface tension forces act in opposition to one another where the coating lies adjacent surface non-uniformities in the web and tend to retain the uniformity of coating thickness achieved at the time of coating.

Abstract: A method for producing light-sensitive material by using a curtain layer of coating solution. The method includes the steps of: discharging coating solution, including the light-sensitive material, from a coater die; forming a curtain layer of coating solution by causing the coating solution to fall from a die lip of the coater die in which the coating solution has at least 3 layers and a relational structure of dynamic surface tensions of the layers, satisfying the equation: .DELTA.K=.sigma.intermediate.sub.min -.sigma.outer.sub.max .gtoreq.0?mN/m! in which, .sigma.intermediated.sub.min ?mN/m! represents the minimum value of dynamic surface tension of an intermediate layer among the layers, .sigma.outers.sub.max ?mN/m! represents the maximum value of dynamic surface tension of an outer layer among the layers; and coating a continuous support with the coating solution.

Abstract: A mixing system with a vessel for supplying a liquid and a device for supplying solid pieces to mix with the liquid. The system has an elongate enclosure with a first end opposing a second end. The enclosure defines a chamber in fluid communication with the vessel to receive the liquid. The chamber also has a inlet and an outlet with the inlet being closer to the first end than the outlet. The chamber receives the pieces from the device through the inlet and issues the pieces through the outlet. A motor driven mixing auger positioned in the chamber between the first and second ends rotates a selected direction about a rotational axis to intermix the liquid and pieces. The auger includes a first helical flight between the inlet and the outlet to convey the pieces from the inlet to the outlet when the shaft is rotated the selected direction. The auger also includes a second helical flight between the first flight and the second end to urge the solid pieces in a direction opposite the first flight.

Abstract: A coating hopper (10) for coating a radiation-sensitive emulsion on a photographic support (24) is fabricated from hopper bars (12) comprising an inlet slot (16) and a discharge slot (18), said bar (12) comprising a body and hopper lip (22), wherein the body of the bar comprises a metal or metal alloy and the lip area comprises a ceramic insert (30) with a high elastic modulus and low density. The hopper with the ceramic insert prevents the formation of streaks in the emulsion coating layer or layers on the support.

Abstract: A method for minimizing coating defects caused by strikethrough when simultaneously slide coating a first fluid layer, a second fluid layer, and a third fluid layer. The method includes preparing the first, second, and third fluids such that the first solute is incompatible with the second and third solutes and such that the first fluid minimizes strikethrough of at least one of the second and third fluids to a slide surface when the first fluid is positioned between the slide surface and the second and third fluids. The present invention is useful in preparing imaging, data storage, and other media.

Abstract: A method for processing substrates, comprising the steps of (a) disposing a substrate on a supporting table, followed by preparing a nozzle and a contact adjusting member in a waiting position apart from the substrate disposed on the supporting table and further preparing removing means in a position intermediate between the waiting position and an operating position, (b) allowing a solvent to be attached to the contact adjusting member in the waiting position and moving the contact adjusting member relative to the nozzle so as to bring the process solution present in the solution discharge port of the nozzle into contact with the solvent attached to the contact adjusting member and, thus, to adjust the condition of the process solution present in the solution discharge port of the nozzle, (c) moving the nozzle from the waiting position to an operating position through the removing means so as to allow the process solution spurted from the nozzle to be moved into the removing means, and (d) moving the substra

Abstract: A method for use with a slide coater including preparing a first coating fluid and flowing the first coating fluid down at least a first slide surface of a slide coater when coating of the first coating fluid onto the substrate is desired and flowing a minimizing fluid down the at least first slide surface when coating of the first coating fluid onto the substrate is not desired. The minimizing fluid has a composition which minimizes drying of the first coating fluid on the at least first slide surface. This invention applies to imaging, data storage, and other media.

Abstract: A method for minimizing waste resulting from defects caused at the edges of a coating on a substrate which was applied to the substrate by a slide coater. A first fluid flows through the first slot main portion at a first flow rate and through the first slot end portions at flow rates which differ from the first flow rate. A second fluid flows through a second slot onto a second slide surface positioned relative to the first slide surface and oriented such that the second coating fluid flows from the second slide surface onto the first coating fluid.

Abstract: A binder applicator for applying binder to a moving substrate includes a distribution pipe extending transverse to the direction of movement of the substrate, with the distribution pipe having a bottom provided with a discharge opening. A distributor channel receives liquid binder from the discharge opening and directs the liquid binder upward. A horizontal reservoir receives the liquid binder material from the distributor channel, and a weir meters the discharge of the binder from the horizontal reservoir to form a thin horizontal flow of liquid binder material. A curved surface receives the thin flow of binder material and gradually changes the flow path to a substantially vertical thin flow of binder material for discharge onto the moving substrate.

Abstract: A solid lubricant application procedure is combined in-line with a steel strip processing method which comprises processing steps upstream and downstream of the lubricant application procedure. The latter comprises applying the lubricant material in molten form or as a solution and may include temperature adjusting steps both upstream and downstream of the lubricant material-applying step. The space for incorporating the lubricant application procedure into the steel strip processing line is limited. The strip speed in the lubricant application procedure is synchronized with the strip speed normally attained in the steel strip processing method in the absence of an in-line lubricant application procedure. The steps of the lubricant application procedure are constrained to accommodate the space limits and strip speed synchronization requirement imposed on the lubricant application procedure when it is combined in-line with the steel strip processing method.

Abstract: Precise control of the wetting of an edge guide by a coating fluid (i.e., the wetting profile) can be achieved by providing a wetting line below which the coating fluid will wet the surface of the edge guide. Preferably, the height of the wetting line corresponds to a predetermined depth profile of a coating fluid flowing down a coater face. Optionally, a non-wetting surface can be provided above the wetting line, and the non-wetting surface can optionally have a low energy coating provided thereon.

Abstract: A method for producing an electrode sheet having a multilayer structure is disclosed, wherein two or more layers for an electrode sheet are simultaneously coated with a coating solution by using a coater.

Abstract: The present invention is a method of producing an imaging support which includes providing a support, simultaneously coating on a side of the support; a transparent magnetic recording layer including magnetic particles, a polymeric binder and an organic solvent, and a lubricating overcoat layer farthest from the support, the lubricating overcoat layer including a lubricant selected form the general formulas I, II or III:wherein general formula I comprises: ##STR1## wherein X is selected from the group consisting of esters, amides, ethers, or methylene, a is from 10 to 500, and b is from 4 to 3000, and the general formula I has a molecular weight at least 800;wherein general formula II comprises: ##STR2## wherein Y is selected from the group consisting of, --C-- and --N--, Z is selected from the group consisting of esters, amides, and a carbon-carbon bond, R is selected from the group consisting of methyl, and hydrogen or may be absent if Y equals nitrogen, c is from 1 to 2, d is from 4 to 3000, e is from 10 t

Abstract: Silica-containing ceramic coatings are produced on substrates at low temperatures by applying a coating comprising a silica precursor on a substrate and heating the coated substrate under an environment comprising nitrous oxide at a temperature sufficient to convert the silica precursor to the silica-containing ceramic coating. This method is especially valuable for forming protective and dielectric coatings on electronic devices.

Abstract: A process for forming an abrasion resistant sheet which comprises forming a web of cellulosic fibers on a papermaking machine and applying a slurry including an abrasion-resistant grit to the upper surface of the web on the papermaking machine using a slot orifice coating head applicator, said grit being uniformly distributed on said surface of said fibrous cellulosic overlay sheet at a coat weight of about 2 to 40 pounds per 3000 square feet.

Abstract: The present invention is a method of producing an imaging support which includes providing a support, simultaneously coating on a side of the support; a transparent magnetic recording layer comprising magnetic particles, a polymeric binder and an organic solvent, and a lubricating overcoat layer farthest from the support, the lubricating overcoat layer comprising wax particles having a size from 0.01 .mu.m to 0.5 .mu.m, and an organic solvent; and drying the magnetic recording layer and the lubricating overcoat layer.

Abstract: A fountain applicator for applying coating liquid onto a web of paper carried past the applicator, has a coating liquid flow path that includes a curved surface along which a sheet of the coating liquid is flowed to subject the sheet to centrifugal force to cause air entrained in the coating liquid to move away from one side of the sheet that is toward the curved surface, so that the one side is relatively free of entrained air. After being flowed along the curved surface, the sheet of coating liquid is directed toward the web in a free standing jet curtain of coating liquid, to contact the web surface primarily with the one relatively air-free side of the coating liquid sheet to decrease the occurrence of skip coating on the web surface, especially when the web is traveling past the applicator at high speeds. The coating is applied in excess onto the web surface and is metered and leveled to a desired coat weight by a downstream doctor.

Abstract: A method and apparatus for coating a moving web with a coating fluid. The coating die has at least one feed slot for supplying the coating fluid to the moving web and a front face demarked from the at least one feed slot by a die edge. A guide mechanism guides the moving web in a first direction past the coating die such that a coating bead is formed in a gap between the moving web and the die edge. The spraying system sprays a cleaning fluid on at least a portion of the front face of the slide coating die such that the coating bead forms a substantially linear static wetting line on the front face of the coating die.

Abstract: The present invention relates to a primer for adhering a polyurethane to a metal oxide coating, to a method of making such a primer, and to a method of adhering a polyurethane protective liner to a metal oxide coating. The primer is a reaction product of a crosslinking agent and a polymer selected from the group consisting of a copolymer of 2-ethylhexylacrylate and acrylic acid, a copolymer of cyanoethylacrylate and acrylic acid and a terpolymer of cyanoethylacrylate, 2-ethylhexylacrylate and acrylic acid.

Abstract: The subject of the present invention is to control the generation of the contamination of a coating apparatus and web tearing which originate in an excess portion of coating color produced when commencing and terminating the coating in curtain coating. Means for solving the subject described above is a curtain coating apparatus in which a curtain film 5 flowing down vertically from a lip head 3 is allowed to contact a continuously running web 9 to form a coated layer, wherein a receiving pan 1 in which at least a coating plate disposed at the tip thereof can move in the running direction of the web 9 is disposed under the lip head 3; the coating plate 2 is connected with one end of the receiving pan 1; and the tip of the coating plate 2 has a function of being capable of sliding in a contact state with the web 9 in commencing and terminating the coating of the curtain film 5.

Abstract: The invention encompasses the pattern coating of a thick layer of adhesive on a single substrate. The adhesive strips may be continuous or discontinuous on the single substrate. In one preferred embodiment of the invention, the substrate is a release liner and the adhesive is a hot melt, thereby not requiring the use of an extruder in the application of the adhesive onto the substrate. When it is desired to produce a non-foamed product, the web is chilled on a chilled drum. Elimination of this chilling step, results in the formation of a foamed tape product, due to the evaporation of the moisture which is typically contained within the silicone-coated paper web. The product is a thick (10-100 mils), free (no carrier) film of adhesive made to the desired width (3/8" to approximately 6") of a high cohesive strength adhesive, with good temperature resistance (>196.degree. F.), with low bubble content (appears clear), wound into rolls containing from 100-800 feet or greater in length.

Abstract: A paint curtain device is proposed in which object (13) to be painted are moved through a paint curtain (5) consisting of liquid paint. In order to make possible the optimal orientation of the objects (13) to be painted, while passing through the paint curtain (5) they are continuously fixed in place on holding means (25) of a conveying system (12) which crosses through the paint curtain (5) when passing through the area of a lateral edge (16). Furthermore, a method for painting objects (13) is proposed for whose execution the paint curtain device is suited.

Abstract: The present invention is an edge blade attached to an edge guide for removing an edge of a falling curtain. The edge of the falling curtain is intercepted by the edge blade and is vacuumed away by a vacuum tube disposed near the edge blade wherein the air flow is blocked to said suction means from the outboard direction and directing said suction means to draw air from the inboard direction towards the curtain; and flushing liquid is distributed to encompass the intercepted liquids of the free falling curtain.

Abstract: The invention concerns a method for improving the uniformity of a liquid curtain which includes the specification of, prior to the coating of the composition under the coating conditions, forming a curtain with flow rate and viscosity conditions (1, 2) which are such that the rear face of the lip is wet over a height greater than the height over which the composition would naturally wet the rear face under the coating conditions. Then, maintaining these flow rate and viscosity conditions over a given period of time.

Abstract: The present invention provides a resist processing method for an object to be processed, including the processing step of supplying a process solution onto the object to be processed to perform a process on the object to be processed, and the cleaning step of supplying a cleaning solution onto the object to be processed to clean the object to be processed, wherein the processing step at least partially overlaps the cleaning step.

Abstract: A method for creating a composite form of coating from a sprayable solution of soluble polyimides and particle materials that are uniformly dispersed within the solution is described. The coating is formed by adding a soluble polyimide to a solvent, then stirring particle materials into the solution. The composite solution is sprayed onto a substrate and heated in an oven for a period of time in order to partially remove the solvent. The process may be repeated until the desired thickness or characteristic of the coating is obtained. The polyimide is then heated to at least 495.degree. F. so that it is no longer soluble.

Abstract: A method of applying a coating of hot melt polymeric material from a die to a substrate. Hot melt polymeric material is extruded through the die onto the peripheral surface of a rotating application roller to provide a coating layer along that peripheral surface. A substrate is conveyed past the peripheral surface of the application roller at an application interface to cause transfer of the first coating layer to the substrate and shearing and thinning of the coating layer because the substrate is conveyed faster than the peripheral speed of the application roller. The velocity of the peripheral surface and spacing between the die and the application interface along are selected to provide a time interval of at least 0.

Abstract: Coating dispenser apparatus and methods which utilize a snuff back device for removing a small amount of coating material from the discharge passage of the dispenser upon shut-off thereof at the end of a coating run. A control is provided which discharges the material removed from the discharge passage back into the discharge passage upon a predetermined delay after the start of the next coating run. The disclosed methods contemplate the discharge of coating material back into the discharge passage in the middle of the next coating pattern, or depending on the application, during any segment of the next coating pattern after a defined leading edge of the pattern is created, during which segment the coating material discharged back into the discharge pattern smoothly blends into the coating pattern as it is applied to a substrate. The apparatus and methods are especially useful for applying conformal coating patterns onto circuit boards.

Abstract: A system for coating a substrate with ultra-thin layers in stripes includes moving the substrate through a coating station and forming a composite layer including coating fluids and a carrier fluid. The composite layer flows at a rate that is sufficiently high to form a continuous flowing fluid bridge of composite layer to the substrate surface and to contact the substrate with the flowing composite layer to interpose the coating layers between the substrate and the carrier fluid. The carrier fluid is removed while leaving the coating fluid deposited on the substrate as a coating layer.

Abstract: A process for coating a front surface of a cathode ray, the process being characterized by using a ultraviolet ray setting plastic material as a coating material. According to the process, a preformed cathode ray tube bulb having a front surface is maintained with the front surface directed upwards and a transparent, fluidized or molten plastic material of ultraviolet setting property is discharged to the front surface of the bulb through a plurality of thin nozzles arranged in at least one row or one or more nozzles each having an elongated nozzle opening. In this instance, it is preferable that the molten plastic material discharged from the nozzles is received by a film forming surface which is arranged adjacent to the nozzles to form a thin plastic film before it reaches the front surface of the bulb. Preferably, the film forming surface is provided by a sheet of a material, such as a silicon rubber, which is not wettable to the plastic material.

Abstract: The present invention is an edge blade attached to an edge guide for removing an edge of a falling curtain. The edge of the falling curtain is intercepted by the edge blade and is vacuumed away by a vacuum tube disposed near the edge blade wherein the blade is extending from the edge guide into the falling curtain to intercept a part of the free falling curtain and positioning the blade above the impingement of the falling curtain on the support wherein the blade is angled into the free falling curtain so that the blade is closest to the support where the part of the free falling curtain is intercepted and farthest from the support at the edge guide. Air to the vacuum tube is blocked from the outboard direction, and the tube is directed to draw air from the inboard direction towards the curtain.

Abstract: The invention concerns an apparatus for improving the uniformity of a liquid curtain in a curtain coating system. The apparatus comprises means for, prior to the coating of the medium, forcing the liquid composition which flows on the forward face of the lip to wet the rear face of the lip of the coating device over a predetermined distance greater than the distance over which the liquid composition would naturally wet the rear face.

Abstract: Methods and apparatuses are disclosed for coating egg-yolk disks containing egg-yolk materials. The egg-yolk is initially produced in the form of a cylinder, which is cut into disks, which disks after being encapsulated into an edible membrane, are used in combination with egg-white to form egg-products which may be fried or poached in a similar manner as real eggs. The methods and apparatuses of the present invention are useful for coating articles other than egg yolk disks.

Abstract: A method of coating moveable supports at high speeds comprises moving a support along a path through a coating zone; forming two or more layers including a topmost layer of coating liquids to form a liquid coating composition; and applying the liquid coating composition to the moving support wherein the topmost layer of the liquid coating composition is shear thinning.

Abstract: A method and composition are disclosed for applying an organic acid-containing aqueous composition to a glass surface to prevent staining thereof wherein a wetting agent is employed to provide uniform and complete wetting of the glass surface with a uniform continuous film of said organic acid-containing aqueous composition.