US3082144A - Extrusion coating under reduced pressure - Google Patents

Extrusion coating under reduced pressure Download PDF

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US3082144A
US3082144A US695341A US69534157A US3082144A US 3082144 A US3082144 A US 3082144A US 695341 A US695341 A US 695341A US 69534157 A US69534157 A US 69534157A US 3082144 A US3082144 A US 3082144A
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Prior art keywords
coating
pressure
web
coated
speed
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Haley Floyd Cresswell
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EIDP Inc
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EI Du Pont de Nemours and Co
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Priority to BE572753D priority Critical patent/BE572753A/xx
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Priority to US695341A priority patent/US3082144A/en
Priority to GB34689/58A priority patent/GB855216A/en
Priority to FR778629A priority patent/FR1227231A/fr
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/74—Applying photosensitive compositions to the base; Drying processes therefor
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
    • D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
    • D21H23/22—Addition to the formed paper
    • D21H23/46—Pouring or allowing the fluid to flow in a continuous stream on to the surface, the entire stream being carried away by the paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H5/00—Special paper or cardboard not otherwise provided for
    • D21H5/0005—Processes or apparatus specially adapted for applying liquids or other fluent materials to finished paper or board, e.g. impregnating, coating
    • D21H5/0042—Processes or apparatus specially adapted for applying liquids or other fluent materials to finished paper or board, e.g. impregnating, coating by pouring or allowing to flow in a continuous stream onto the surface, the entire stream being carried away by the paper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D1/00—Processes for applying liquids or other fluent materials
    • B05D1/26—Processes for applying liquids or other fluent materials performed by applying the liquid or other fluent material from an outlet device in contact with, or almost in contact with, the surface
    • B05D1/265—Extrusion coatings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D2252/00—Sheets
    • B05D2252/02—Sheets of indefinite length
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/04—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to gases
    • B05D3/0493—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to gases using vacuum

Definitions

  • this invention relates to a process of applying a coating of a viscous fluid onto a continuous, moving flexible web at reduced pressures and at high speeds. Still more particularly, this invention relates to a process of coating aqueous water-permeable colloid silver halide dispersions onto base materials such as films, foils and papers as layers in photographic elements.
  • Johns U.S. Patent No. 2,795,522 Johns teaches the introduction of a condens'able vapor into a reduced pressure coating atmosphere, so that entrapment of any ambient vapor will not result in on-condensable bubbles, but rather any vapor which-may be entrapped between the web and the coated layer will condense in an unobjectionable manner and not remain in the form of bubbles.
  • Johns patent it has been found that some difficulty may be experienced in, maintaining a completely saturated, instantaneously condensable atmosphere which is free from non-condenthe coating zone had to be above the equilibrium pressure of the material being coated. In other words, the
  • Viscous coating fluids within the scope of this invention which have been coated onto flexible webs according to methods known in the prior art, have been dried chilled and then exposed to high velocity air which has sable gasses in the immediate vicinity of the coating station, and at the same time preventing the formation on the coated product of droplets of liquid resulting from condensation of the particular vapor introduced into the coating zone.
  • the aforementioned Beck U.S. Patent No. 2,815,307 discloses the application of external heat, as by electrical platens, to provide sutficient heat of vaporization to remove the solvent from the newly coated material, the drying proc ess also taking place at greatly reduced pressures.
  • An object of this invention is to provide a novel process of coating viscous fluids, and in particular photo-t graphic materials, at speeds heretofore unattainable and at pressures below the static equilibrium pressure. Another object is to provide such a method wherein the applied coatings are of uniform thickness and free from entrapped bubbles betweenthe coatingand the supporting web. Still another object is to provide such a method wherein extremely thin coatings of high quality can be made. Yet another object is to provide a method of coating viscous water-permeable colloid dispersions and especially aqueous colloid silver halide dispersions'onto continuous film or paper at high rates of speed. An additional object is to provide such a method which can be carried out in a relatively simple apparatus.
  • a further object of this invention is to provide a process for applying a viscous fluid by extrusion as a coating onto a flexible web whereby the extruded material is chilled and set without the application of external refrig' eration.
  • a still further object isto provide a process for coating and drying a viscous fluid without the application of external heat.
  • Yet a further object is to provide a drying process wherein the carrying medium in a newly applied coating of a viscous fluid is removed from the coated layer as a liquid without the necessity of vaporization.
  • Another object is to provide a process which permits drying films at low temperatures and also low pressures without the necessity of having different pressures in the coating and drying areas which can only be achieved by a two-chamber system separated by vacuum sealing arrangements.
  • a particular object is to provide a continuous coating and drying process to produce commercially acceptable coated film elements at speeds up to 2,400 feet a minute and even higher. Still other objects will be apparent from the following description of the invention;
  • the present invention in its broadest aspects therefore comprises the web coating process of extruding in a coating zone a coating material in the form of a fluid (which can be a solution or a dispersion in a solvent or other suitable carrying medium) of high viscosity through a narrow orifice onto a-moving web traveling at a higher linear speed than the fluid being extruded, while the coating zone is at an absolute pressure above the apparent equilibrium pressure of the coating material at the speed of the moving web and below the static'equilibrium pressure of the coating material and furthermore below the air occlusion pressure, i.e., the pressure at which air drawunder occurs, said coating material at extrusion being at a temperature above the set point of the coating material and below a temperature at which damage due to heat occurs to the coating material, and removing the carrying medium from the coated material.
  • a coating material in the form of a fluid which can be a solution or a dispersion in a solvent or other suitable carrying medium
  • the invention can be restated as being the process of extruding a high viscosity fluid through a narrow orifice in the form of a thin sheet onto a moving web traveling at a higher linear speed than the fluid being extruded, at a temperature above the set point of the fluid and below a temperature at which the coating material would be damaged due to heat, in a low pressure atmosphere and at a coating speed, said atmosphere and speed being within the limits indicated by the shaded area between curve A and curve B of FIGURE 2 of the drawing, and removing the carrying medium from the coated material.
  • the expression carrying medium" of the coating material is intended to mean the solvent, when the coating material is in the form of a solution.
  • the expression is also intended to encompass the fluid medium in which particulate solids are dispersed or suspended in a dispersion or suspension or similar system. Combinations of two or more carrying mediums can of course be used in the same coating material.
  • the preferred carrying medium is water.
  • high viscosity a viscosity of the coating material in the range from 1,000 to 100,000 centipoises, and preferably in the range from 4,000 to 10,000 centipoises.
  • the critical factor is the viscosity.
  • a viscous aqueous dispersion of light-sensitive silver halides in a waterpermeable, natural or synthetic colloid at a temperature above the set point (solidification temperature), and preferably at least about 8 F.
  • a coating zone in the form of a thin sheet onto a continuous flexible web, e.g., a thin film base or paper that is traveling at a linear speed from 2 to 200 times faster than the speed of extrusion of said dispersion, said dispersion having a viscosity in the range from 1.000 to 100,000 centipoises, and preferably 4,000 to 10,000 eentipoises, and a solids content in the range from 20 to 65%, and preferably from 48 to 55%, while maintaining the atmosphere in the coating zone at an absolute pressure above the apparent equilibrium pressure of the dispersion at the speed of coating and at an absolute pressure below the static equilibrium pressure of the dispersion at that temperature and furthermore below the pressure at which air draw-under occurs, and effecting removal of water from the newly coated sheet.
  • the material to be coated is prepared at the preselected viscosity and temperature by any suitable procedure.
  • Photographic materials (lightsensitive or not) to be coated can be prepared in dilute emulsion form in a conventional manner.
  • Outgassing, concentration to the preselected viscosity and to the desired solids content where appropriate, and temperature adjustment of the emulsion can be readily effected, for example, in apparatus which is described in Haley U.S. application Serial No. 525,570, filed August 1, 1955 (Patent No. 2,866,499, December 30, 1958).
  • Suitable coating aids and other additives can be admixed with the emulsion, as will be understood in the art, which is then ready to be extruded under the conditions according to this invention.
  • a tem-' perature decrease of F. upon extrusion effects a net cooling of 30 F. belowthe set point or solidification temperature of .the coating material. of the material is not instantaneous but requires a small amount of time even' at this temperature, 'the material does-not setup until it has'contacted the support.
  • thecarrying medium e.g., the-solvent such as water
  • the-solvent such as water
  • the solvent can be removed by mechanical means, e.g., wi'ped or squeegeed from thesurface of the coated material by sponges on rotating rolls; air-knif'ed from the surface by apparatus described for example in US. Patent No. 2,139,628, removed by a simple vacuum device, or-the like.
  • the coated material can also be dried by-conventhe aforementioned- Beck US. patent.
  • the external application of heat'as-by electrical platens of conventional drying meth ods (3) is combined with the drying process -(1 )wherein the coated Web-is maintained for a few seconds below thestatie equilibrium pressure.
  • the wattage supplied to the heaters will he obviously selected to provide sufficient heat to evaporate the solvent which will be removed at a temperature corresponding to the pressure selected.
  • FIG. l is a schematic representation of a suitable apparatus for carrying out this invention.
  • FIG. 2 is a graph showing the coating pressure-web speed relationship necessary according to the present invention.
  • FIG. 3 is a detailed schematic view illustrating the coating operation according to this invention, with parts greatly enlarged for purposes of-clarity and not necessarily drawn to scale;
  • FIG. 4 is a graph similar to that ofFIG. 2 illustrating the effect of a variation of process conditions.
  • FIG., 5 is a composite graph showing the relationship between the viscosity, temperature and solids content for particular coating fluids which can be coated satisfactorily according to this invention.
  • FIG. 1 a suitable apparatus is shown schematically in FIG. 1 wherein 1 is a chamber into which a web of paper or film 2 passes through inlet or feed rolls 3, downwardly and around guide rollers 4 and 5,.and over coating roller 6 which constitutes the point of coating, illustrated in greater detail in FIG. 3.
  • the coated web passes overadjustable roller 8, thence around guide rollers 9,, 10 and 11, and travels outwardly from chamber 1 through .exit or outlet rolls 12
  • Any or all of the web guiding rollers-including the coating roller 6 and the adjustable roller 8 can be driven or. idler rolls as desired.
  • An alternate apparatus can be'used, of course, in which the web supply roll and take-up roll are in the vacuum chamber and new web supplies are introduced and coated stock removed through vacuum locks.
  • Extrusion hopper 7 can be supported by any suitable means (not shown) and can conveniently be connected,- as by. means of a suitable pipe.l3,,to a continuous source or supply (not shown) of coating material, as will bereadily understood.
  • the temperature of the extrusion is not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to, but not limited to,
  • hopper can be controlled by any suitable means, such as internal channels or ducts positioned asdesired within the device. adjacent the extrusion lips and/or elsewhere throughoutthe body of the hopper, and connected to a'suitable source of heating or cooling gas or liquid medium.- Alternatively, electric resistance heaters can be located in the hopper and lip structures. The wall of the chamber can be conveniently provided with a window so-that the coating operation can be observed.
  • suitable means such as internal channels or ducts positioned asdesired within the device. adjacent the extrusion lips and/or elsewhere throughoutthe body of the hopper, and connected to a'suitable source of heating or cooling gas or liquid medium.
  • electric resistance heaters can be located in the hopper and lip structures.
  • the wall of the chamber can be conveniently provided with a window so-that the coating operation can be observed.
  • Opening 14 in the chamber 1 is connected by any conin criticality; Two such factors include (1).”t he'path the self supporting' extruded sheet of coating material takes as itjeffectscontact with the flexible web support,-
  • v'acuum pump or aspirator (not shown) for reducing the pressure within the chamber.
  • the horizontal dotted line represents the static equilibrium pressure of the coating material at the coating temperature, conveniently expressed in millimeters of-mercury. It is this level of pressure which has heretofore been considered the absolute minimum below which coating could not be satisfactorily accomplished.
  • the static equilibrium pressure will not be the same for all materials being coated, and will'varywith the ingredients of the coatingmaterial, e.g., the solvent, type of solids, etc., as
  • the gas occlusion or air draw-under pressure has likewise been found to vary with the coating speed. As can be seen from FIG. 2, the occlusion pressure decreases below the static equilibrium pressure at a gradual rate, much less than the rate of decrease of the apparent equilibrium pressure. Above curve B, gas occlusion or air draw-under will take place, while below curve B but 7 ing speeds at more or less indefinitely rapid coating speeds.
  • the extrusion hopper 7 is shown extruding a thin film of coating material 15, which moves in a self-supporting manner until it effects contact with the oncoming uncoated web 2 as the latter passes around coating roller 6. Layers 2 and 15 move into laminar contact with each other, and readily adhere to each other with or without the aid of interposed adhesives as will be understood in the art.
  • the coated article moves onward and around adjustable roller 8, as more clearly shown in FIG. 1.
  • the dotted line 16 shows the path the free self-supporting layer 15 would take as it is being extruded onto the moving web 2 if tension were the only force acting on the material upon extrusion.
  • the force due to the adhesion between layer 15 and web 2 causes the point of contact of the coating material with the web to be positioned away from point of tangency 17 at a position where the force of adhesion equals the force resulting from tension.
  • the presence of any other forces acting to affect the forces of adhesion and tension will upset the balance, effecting the movement of the point of contact forward toward the point of tangency 17 and thus allow gas from the coating atmosphere to be trapped between layer 15 and layer 2.
  • the pressure buildup in the nip of the layers 15 and 2 can be controlled at a minimum by rerucing the density of the atmosphere surrounding the nip to a level as low as operably possible...
  • a direction of travel of self-supporting film 15 more further removed from the tangential will be obtained at pressures closely adjacent to curve A.
  • a second way of maintaining the non-tangential relationship of the coating layer at the coating roller can be accomplished by positioning the lips .or extrusion orifice of the hopper as close to the coating roller 6 as possible.
  • the actual distance which the self-supporting film 15 will travel from the extrusion orifice to the point of contact with the flexible web 2 will depend on the structural limitations of the coating apparatus.- It has been found that particularly advantageous results are obtained when this distance is less than about one-eighth of an inch.
  • a third way of maintaining the aforementioned relationship is by elimination of centrifugal force acting on the material being coated.
  • the direction at which the outrunning coated article leaves the coating roller 6 can be effective ly adjusted and controlled by positioning adjustable roller 8 about a pivot as desired.
  • This has been found to be particularly essential at high coating speeds on the order of 600 or 700 feet per minute and higher in order to overcome the adverse effects of centrifugal force acting on the newly applied coating material.
  • the effect of the angle can be demonstrated at speeds about feet per minute.
  • the angle of adjustment of the adjustable roller 8 can be conveniently described as angle theta having its apex at tangential point 17, as illustrated in the drawing.
  • the angle theta should be maintained preferably within the range from 178 to 184
  • the angle theta should be maintained preferably within the range from 178 to 182
  • the angle theta should be maintained preferably within the range from 178 to 181.
  • extrusion of the self-supporting sheet of coating material is in a plane non-tangential-to the coating roller or equivalent support, and not in the same plane as the outgoing coated products, and not necessarily in a plane parallel to the plane of the outgoing product.
  • FIG. 4 represents the pressure-speed relationship wherein the coating process takes place utilizing the apparatus shown in FIG 3 except that the angle theta adjustment of the adjustable roller 8 is greater than 184. It will be noted that this improper setting of the angle theta causes curve A and curve B to approach each other with increase in coating speed. It has also been found that this relationship between these two curves A and B, wherein the acceptable coating region is reduced to a negligible amount or completely eliminated, will result when the coating material has properties outside the ranges defined in the appended claims.
  • the composite graph shows the relationship between viscosity, temperature, and solids content for typical suitable coating materials within the scope of this invention.
  • curve C of FIG. 5 represents the viscositytemperature characteristics for an aqueous gelatin solution containing 20% by weight solids.
  • Curve D represents the viscosity-temperature characteristics for an aqueas the latter is extruded through the orifice.
  • Curve G represents the viscositytemperature characteristics for an aqueous cyan color- .forming polyvinyl acetal silver halide emulsion of 32% solids content.
  • Graphsof the type plotted in FIG. can be prepared conveniently for other fluids to'be coated according to this invention.
  • the set point or solidification temperature is indicated as the point at which the slope of the curve approaches infinity. This is shown, for example, with respect to curve D as the two vertical' dotted lines indicating that the setpoint for a particular 45% solids aqueous gelatino silverhalide photo'graphic emulsion is about 95 F.
  • the pressure in the coating'zone can be varied over a fairly wide range for any given coating speed, and likewise the coat- .ing speed can be varied over a fairly wide range for any 1 out the process of this invention extends from about 40 millimeters of mercury absolute at 100 feet per minute to slightly below 20 millimeters of mercury at speeds in ex-' cess of 500 feet per minute. Atan intermediate pressure of about 35 millimeters of mercury absolute, excellent coating quality without objectionable draw-under of air curve and the air draw-under ourve (curves 'A and B of FIG. 2) will generally follow the pattern illustrated in FIG. 2.
  • the emulsion supply system which may conveniently include a metering pump or similar device, and the web speed are paced together so that the web moves at a linear speed of about l0-times that of the coating material
  • The'coating material at the orifice is maintained at about 105 R, which has been determined from the curve of the type shown in FIG. 5 to be about 8 to 10 F. above the set point of the coating material.
  • the total pressure of the atmosphere in the coating chamber is reduced by a vacuum pump or other suitable means. While the web is runningat a low speed, the coating chamber pressure is reduced to about 60 millimeters of mercury absolute, and the coating speed is increased to approximately 200 feet per minute whereupon air draw-under occurs. The pressure is then reduced to about 58 millimeters of mercury absolute (static equilibrium pressure) and air draw-under ceases.
  • the coatingspeed is increased to about 380 feet per minute whereupon air draw-under commences, and next the pressure is dropped to about 56 millimeters of mercury absolute at which time air draw-
  • the total pressure in the coating chamber can be reduced until boiling occurs-and increased until feet per minute and above.
  • the process of this invention is applicable to the simultaneous coating of more than one layer onto a supporting web.
  • Suitable apparatus for such multiple coating is described, for example, in Beck U.S. application Serial No. 506,458, filed May 6, 1955 (Patent No. 2,901,770, Sept. '1, 1959).
  • Example 1 A light-sensitive aqueous gelatino silver halide photographic emulsion of the medical X-ray type having a viscosity of 6,800 centipoises at the coating temperature of F. and a solids content of 50% by weight was coated onto a gelatin sublayer on a cellulose acetate web, using apparatusof the type shown in FIG. 1.
  • the coating chamber was provided withan extrusion hopper of the type describedin Velvel U.S. Patent No. 2,765,492, t-he orifice of which was adjusted to 0.006 inch.
  • Electrical heating platens of the type described in the aforementioned Beck U.S.-application Serial No. 375,404 were positioned within the coating chamber adjacent the coatface defects. The drying time after coating until the web was wound on a roll satisfactorily was about two seconds.” 7 The coated web furthermore was lacking in boiling streaks and objectionable. entrapped bubbles due to air drawunder.
  • Example 2 Example 1 was repeated except thatt he viscosity of the emulsion was 5,800 centipoises, and the coating-temperature was increased to F.
  • the coating conditions maintained in Example 1 were repeated to a web speed of about 380 feet per minute and a pressure of 30 millimeters of mercury absolute, after which the web speed was increased slowly to 750 feet per minute. Excellent quality coated material was obtained throughout the range of coating speeds from 380 to 750 feet per'minute.
  • Example 3 Example 1 was repeated except that the emulsion was concentrated to 52% solids by weight and had a viscosity of 11,600 centipoises at 105 F. Extrusion coating took place at a chamber pressure of 47.5 millimeters of mercury absolute and'a web speed of 220 feet per minute.
  • Example 4 Example 3 was repeated except that the speed of the web was gradually increased from 220 feet per minute to 600 feet per minute and the pressure reduced to 41.5 millimeters ,of mercury absolute. Excellent coating results were obtained throughout this entire range.
  • Example 5 Example 3 was-repeated except that the coating chamber pressure was reduced to 35 millimeters of mercury absolute as the web speed was increased to 550feet per minute. Excellent coating quality was obtained throughout this entire' range.
  • Example 6 Example 1 was repeated except that the emulsion had a solids content of about 55% by weight and a viscosity of 21,000 centipoises at 105 F. The extrusion coating took place at a web speed of about 400 feet per minute and the coating chamber pressure was 39 millimeters of mercury absolute. The same excellent results of Example 1 were obtained.
  • Example 7 A light-senitive aqueous gelatino silver halide photographic emulsion having a viscosity of 5,600 centipoises at 105 F. and a solids content of about 52% by weight, to which a conventional emulsion hardener was added in the amount usually employed in the art for the weight of gelatin in the emulsion, was coated onto a polyethylene terephthalate supporting web made in the manner described in Alles and Saner US. Patent 2,627,088 employing .a vinylidene chloride/eo-methylacrylate/co-itaconic acid copolymer coating which was overcoated with a conventional gelatin sub. The lips of the extrusion hopper were spaced 0.010 inch apart. A coating roll inch in diameter was used. The pressure in the coating chamber was reduced to 58 millimeters of mercury absolute and coating was started. Excellent coating quality was obtained as the speed of the web was increased to 360 feet per minute, at which speed air draw-under started.
  • the speed of the web was maintained at 360 feet per minute and the pressure was reduced to 21 millimeters of mercury absolute at which pressure boiling was observed to begin. Excellent coating quality, however, was obtained throughout the entire range from 58 to 21 millimeters of mercury absolute at the coating speed of 360 feet per minute.
  • the obtained coating weight was 81.4 milligrams of silver per square decimeter.
  • Example 8 A light-sensitive aqueous gelatino silver halide photographic emulsion of the medical X-ray type was prepared and concentrated to a solids content of about 50% by weight using apparatus described in Haley U.S. application Serial No. 525,570 filed August 1, 1955 (Patent No. 2,866,499). The emulsion had a viscosity of 7,500 centipoises at 110 F. Separately, an anti-abrasion gelatinous coating solution was concentrated in the aforementioned Haley apparatus to a solids content of about 35% by weight, and the resultant concentrated solution had a viscosity of about 3,500 centipoises at 110 F. The two fluids were coated simultaneously from the dual extrusion hopper described in Beck U.S.
  • Example 9 Example 8 was repeated except that the materials coated from the dual extrusion hopper were (1) a cyan color-forming polyvinyl acetal silver halide aqueous emulsion of the type described in Martin US. Patent 2,538,257, and .(2) amagenta color-forming polyvinyl acetal silver halide aqueous emulsion of the type described in Martin US. Patent 2,680,732.
  • the emulsions were each concentrated separately to a viscosity estimated to be 6000 centipoises at a temperature of 110 F.
  • the coating chamber pressure was adjusted to 60 millimeters of mercury absolute.
  • the extrusion orifice openings were each .006 inch and the web speedwas maintained at about feet per minute. Examination of the resultant composite structure showed two clearly defined, smooth layers of excellent quality.
  • Example 10 A light-sensitive aqueous gelatino silver halide photographic emulsion of the positive type having a solids content of about 53% by weight and a viscosity of 5,600 centipoises at 110 F. was coated as described in Example 1, except that the coating chamber pressure was maintained at 48 millimeters of mercury absolute, the web speed was 200 feet per minute, and the heaters were removed. The coated web was wound up without any external drying air. Upon inspecting the coated web, the usual glossy smooth surfacewas observed. The coated surface of the web was not tacky and was substantially free from solvent.
  • Example 11 A light-sensitive aqueous gelatino silver halide photographic emulsion of the positive type having a solids content of about 49% by weight and a viscosity of 4,400 centipoises at 110 F. was coated as described in Example 1, except that the hopper opening was increased to 0.010 inch, and the coating chamber pressure was reduced to 40 millimeters of mercury absolute as the web speed was brought up to about 500 feet per minute. The pressure was maintained at 40 millimeters, and the web speed gradually increased to 1,650 feet per minute. The coated web was wound up without application of external heat for drying. Upon inspecting the coated web, the surface was found to be substantially dry and the coating quality satisfactory.
  • Example 12 A light-sensitive aqueous gelatino silver halide photographic emulsion of the negative type having a solids content of about 55% and a viscosity of 7,600 centipoises at 110 F. was coated as described in Example 1, except that the coating chamber pressure was reduced from the static equilibrium pressure (about 67 millimeters of mercury absolute) to 60 millimeters of mercury absolute as the web speed was increased to 200 feetper minute.
  • the coating chamber pressure was reduced from the static equilibrium pressure (about 67 millimeters of mercury absolute) to 60 millimeters of mercury absolute as the web speed was increased to 200 feetper minute.
  • chamber pressure was further reduced to 45 millimeters of mercury absolute as the web speed was increased to 2,000 feet per minute.
  • the coated web was wound up without application of external heat for drying. Examination of the coated 'web showed a complete lack of objectionable air occlusions, and generally excellent coating characteristics.
  • Example 13 A light-sensitive aqueous gelatino silver halide photographic emulsion of the negative type to which a hardenspeeds and pressures.
  • centipoises at 110 F. was coated as described in Example, 1, except that the-coatingehamber pressure was progressively reduced from a' static equilibrium pressure of about 67 millimeters. of mercury absoluteuat the starting coating speed, as shown in the following table.
  • Sensitometricjdata were equivalent to those of thesame emulsion in dilute form'coated by the skim coating process.
  • Example 14- Example 1-3 was repeated except that the coating hopper lip opening was increasedto 0.0l2 inch, and the coating and drying was'accornplished atthe following web Pressure in millimeters of mercury absolute Pressure in. millimeters -14 of such alcohols with each other or with ltctones, e.g., acetone, methyl ethyl ketone, methyl propyl ketonc,
  • the invention is usefulin preparing a product or article wherein it is desired to apply one or moresurface layers'of a coating material to a supporting web. It will thereforebe understood that the invention is useful in 'preparing' 'photographic film elements including multicolor films, intersect films of a positive or negative type, printing papers, X-ray films, motion picture films,
  • Coating'materials can also include conventional additives, aswill be understood in the art, suchas chemical hardeners, 'e.g., mucochloric acid and chrome alum. It
  • Example 15 A positive type light-sensitivesilver halide photographic.
  • An advantage of this invention resides in the fact that viscous-fluid material and in particular photographic material can becoatedat speeds and coating pressures heretofore unattainable without deleterious effect on the quality and especially the photographic properties of the coat- 7 ed article. Another advantage is that photographic films web speedwasj increased to 1,200 feet per minute.
  • coated web from which a large amount of clear, supernatant liquid could be removed mechanically was wound up without application of external heat for drying.
  • a coated article of acceptable quality was obtained.
  • the process of this invention is useful in the coating of of natural and syntheic water-permeable cooloids'which have been used as binding agents for the silver halide grains, including gelatin, albumen, agar-agarfwater-permeable polyamides, polyvinyl alcohol, partially hydrolyzed polyvinyl esters, hydrophilic polyvinyl acetals including those containing color-former nuclei, and othertypes of viscous binder materials. It is particularly useful in I the coating of aqueous gelatino silver'halide emulsions.
  • the process is not limited to the coating of silver halide emulsion layers;
  • the process-can also be used in the coating of gelatin sub-layers, gelatin filter layers,"antihalation layerswhich contain dyes and pigments which absorb preselected wavelengths of light, anti-abrasion layers, water proofinglayers', sublayers, etc.
  • the process is useful in the coating of dispersions of magnetizable materials or phosphors in suitable carrying mediums. 1 I 4 While it is preferred that the carry-ing medium be aqueous' such as water, aqueous ethanol, etc.,.
  • 'theprocess is useful in the applicati'oriof coating'materials inorganicsolvents, e.g., alcohols such as methyl, ethyl, propyl, and butyl alcohols, and mixtures light-sensitive silver halide dispersions in the various types 40 ratio of 065, having a solids content of about 11.8% by weight and a viscosity of about 1,200 centipoises at 110 1 F.,' was coated as described in Example 12.' The coating cal than prior art and papers are obtained having improved surface characteristics and an absence of objectionable air occlusion beneath the coating. .Still another advantage is that the process is readily controllable and permits coating at a wide range of speeds and pressures.
  • alcohols such as methyl, ethyl, propyl, and butyl alcohols
  • mixtures light-sensitive silver halide dispersions in the various types 40 ratio of 065, having a solids content of about 11.8% by weight and a viscosity of about 1,200 centi
  • a further advantage resides in the fact that the process can be carried out in apparatus which does not require the maintenanceof differential pressures,not require the introduction of condensable vapors, nor require precise control of the temperature in the coating zone.
  • a still truding at a speed from $6 to 1200 feet per minute a coating material comprising an aqueous solution of a waterpermeable organic colloid having a viscosity in the range from 1,000 to 100,000 centipoises and a solids content in the range from 20% to by weight, in the form of a thin sheet, into a low pressure coating zone and onto a moving flexible web traveling at a linear speed from to 2400 feet per minute and 2 to 200 times faster than the speed of extrusion, while maintaining said coating zone at a temperature above the set point of said solution and below aboutlS O F.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Coating Apparatus (AREA)
US695341A 1957-11-08 1957-11-08 Extrusion coating under reduced pressure Expired - Lifetime US3082144A (en)

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BE572753D BE572753A (xx) 1957-11-08
US695341A US3082144A (en) 1957-11-08 1957-11-08 Extrusion coating under reduced pressure
GB34689/58A GB855216A (en) 1957-11-08 1958-10-29 Improvements relating to the coating of moving webs
FR778629A FR1227231A (fr) 1957-11-08 1958-11-07 Perfectionnements à l'enduction de nappes en mouvement

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3206323A (en) * 1962-06-12 1965-09-14 Eastman Kodak Co Coating high viscosity liquids
US3751280A (en) * 1970-02-06 1973-08-07 Ici Ltd Method of producing a photographic film base having a subbing layer
US4041198A (en) * 1975-10-01 1977-08-09 General Steel Industries, Inc. Apparatus and method for forming water stops on insulated pipe
US4051278A (en) * 1975-06-06 1977-09-27 Eastman Kodak Company Method for reducing mottle in coating a support with a liquid coating composition
US4113815A (en) * 1974-07-11 1978-09-12 Yuzo Kawamura Method for manufacturing composition including fine particles dispersed therein
EP0168986A2 (en) * 1984-07-06 1986-01-22 E.I. Du Pont De Nemours And Company Device for the application of at least one coating layer and a process for the operation of this device
EP0197493A2 (en) * 1985-04-01 1986-10-15 Wang Zhongjun Vertical drawing curtain coating method and apparatus
US5194190A (en) * 1989-03-31 1993-03-16 General Electric Company Process for impregantion of glass fiber reinforcement with thermoplastic resins
US5447753A (en) * 1991-06-07 1995-09-05 Nippon Paper Industries Co., Ltd. Method of manufacturing coated paper for printing
US20050218066A1 (en) * 2004-03-30 2005-10-06 Nordson Corporation Hot melt adhesive system with ultrasonic filter and filtering method
US20070095661A1 (en) * 2005-10-31 2007-05-03 Yi Wang Method of making, and, analyte sensor
US20090027597A1 (en) * 2006-04-27 2009-01-29 Nitto Denko Corporation Method for producing polarizing film, and liquid crystal display device

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EP0002040B1 (de) * 1977-11-21 1981-12-30 Ciba-Geigy Ag Verfahren zur Herstellung von Lötstoppmasken auf gedruckten Schaltungen mit Druckkontaktierungsbohrungen
EP0031301A1 (de) * 1979-12-20 1981-07-01 Ciba-Geigy Ag Verfahren und Vorrichtung zum Beschichten von photographischen Trägerbahnen mit photographischen Beschichtungsmassen
ATE53682T1 (de) * 1983-09-06 1990-06-15 Energy Conversion Devices Inc Verfahren zur herstellung von grossflaechigen integrierten schaltungen.

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US1180255A (en) * 1914-05-14 1916-04-18 Ansco Company Process for coating and drying photographic papers, photographic-film support, and similar manufactures.
US1861918A (en) * 1928-01-30 1932-06-07 Eastman Kodak Co Process of conditioning photographic films
US2175125A (en) * 1937-06-15 1939-10-03 Reynolds Res Corp Method for forming films and film coatings
US2681294A (en) * 1951-08-23 1954-06-15 Eastman Kodak Co Method of coating strip material
US2795522A (en) * 1953-08-19 1957-06-11 Du Pont Processes of coating
US2815307A (en) * 1953-08-20 1957-12-03 Du Pont Processes for coating and drying photographic layers

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1180255A (en) * 1914-05-14 1916-04-18 Ansco Company Process for coating and drying photographic papers, photographic-film support, and similar manufactures.
US1861918A (en) * 1928-01-30 1932-06-07 Eastman Kodak Co Process of conditioning photographic films
US2175125A (en) * 1937-06-15 1939-10-03 Reynolds Res Corp Method for forming films and film coatings
US2681294A (en) * 1951-08-23 1954-06-15 Eastman Kodak Co Method of coating strip material
US2795522A (en) * 1953-08-19 1957-06-11 Du Pont Processes of coating
US2815307A (en) * 1953-08-20 1957-12-03 Du Pont Processes for coating and drying photographic layers

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3206323A (en) * 1962-06-12 1965-09-14 Eastman Kodak Co Coating high viscosity liquids
US3751280A (en) * 1970-02-06 1973-08-07 Ici Ltd Method of producing a photographic film base having a subbing layer
US4113815A (en) * 1974-07-11 1978-09-12 Yuzo Kawamura Method for manufacturing composition including fine particles dispersed therein
US4051278A (en) * 1975-06-06 1977-09-27 Eastman Kodak Company Method for reducing mottle in coating a support with a liquid coating composition
US4041198A (en) * 1975-10-01 1977-08-09 General Steel Industries, Inc. Apparatus and method for forming water stops on insulated pipe
EP0168986A3 (en) * 1984-07-06 1987-09-23 E.I. Du Pont De Nemours And Company Device for the application of at least one coating layer and a process for the operation of this device
EP0168986A2 (en) * 1984-07-06 1986-01-22 E.I. Du Pont De Nemours And Company Device for the application of at least one coating layer and a process for the operation of this device
EP0197493A3 (en) * 1985-04-01 1987-09-30 Wang Zhongjun Vertical drawing curtain coating method and apparatus
EP0197493A2 (en) * 1985-04-01 1986-10-15 Wang Zhongjun Vertical drawing curtain coating method and apparatus
US5194190A (en) * 1989-03-31 1993-03-16 General Electric Company Process for impregantion of glass fiber reinforcement with thermoplastic resins
US5447753A (en) * 1991-06-07 1995-09-05 Nippon Paper Industries Co., Ltd. Method of manufacturing coated paper for printing
US20050218066A1 (en) * 2004-03-30 2005-10-06 Nordson Corporation Hot melt adhesive system with ultrasonic filter and filtering method
US20070095661A1 (en) * 2005-10-31 2007-05-03 Yi Wang Method of making, and, analyte sensor
WO2007053497A3 (en) * 2005-10-31 2007-11-29 Abbott Diabetes Care Inc Analyte sensor and method of making it
US20110031110A1 (en) * 2005-10-31 2011-02-10 Yi Wang Methods of Making, and, Analyte Sensor
US8795477B2 (en) 2005-10-31 2014-08-05 Abbott Diabetes Care Inc. Methods of making, and, analyte sensor
US9290839B2 (en) 2005-10-31 2016-03-22 Abbott Diabetes Care Inc. Method of making, and, analyte sensor
US20090027597A1 (en) * 2006-04-27 2009-01-29 Nitto Denko Corporation Method for producing polarizing film, and liquid crystal display device

Also Published As

Publication number Publication date
GB855216A (en) 1960-11-30
FR1227231A (fr) 1960-08-19
BE572753A (xx) 1900-01-01

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