Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C1/00—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating
  • B05C1/04—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length
  • B05C1/08—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line
  • B05C1/0856—Reverse coating rollers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C1/00—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating
  • B05C1/04—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length
  • B05C1/08—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line
  • B05C1/0817—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line characterised by means for removing partially liquid or other fluent material from the roller, e.g. scrapers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C1/00—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating
  • B05C1/04—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length
  • B05C1/08—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line
  • B05C1/086—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line a pool of coating material being formed between a roller, e.g. a dosing roller and an element cooperating therewith
  • B05C1/0865—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line a pool of coating material being formed between a roller, e.g. a dosing roller and an element cooperating therewith the cooperating element being a roller, e.g. a coating roller
• • 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
  • B05D1/28—Processes for applying liquids or other fluent materials performed by transfer from the surfaces of elements carrying the liquid or other fluent material, e.g. brushes, pads, rollers
• • 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
  • B05D2202/00—Metallic substrate
• • 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

Definitions

• the present invention relates to a process and a device for continuously coating, in a wide range of thickness, at least one substrate with a film of an organic and / or mineral formulation in the state of solution or dispersion and whose viscosity is between 0.001 and 100
• This type of process is used in particular for applying paints in the form of solutions or dispersions in an organic solvent on moving substrates, for example on metal strips.
• a roller coating technique which consists in introducing paint, by gravity, into the air gap of a metering roller and a pick-up roller.
• a paint film of controlled thickness is formed on an applicator roller in contact on one side with the pick-up roller, and on the other side with the moving strip, then all or part of the coating.
• the applicator roller is a roller whose surface is deformable.
• Deformable surface rollers are generally formed from a metallic core coated with a layer of elastomer.
• the contact of the applicator roller with a deformable surface on the strip associated with the pressure exerted on the latter, generates a degradation of the coating of this roller, in particular at the level of the edges of the strip.
• the friction of the metal strip against the coating of the applicator roller generates in the long run a notch of the periphery of the roller of the same width as the width of the strip.
• the operator is therefore forced to program the passage of the strips in cone of decreasing widths so as to pass the widest strips before the narrower strips;
• the wear on the coating of the applicator roller is too marked or when we reach the end of the cone and start again scrolling strips of large widths, it is necessary to change the applicator roller to either rectify or re-fill.
• the wear of the coating of the applicator cylinder generates particles of this coating which risk causing coating defects by polluting the coating film.
• the friction between the applicator roller and the strip is low . It is then possible to deposit films of very fluid formulation whose viscosity is less than 0.01 Pa.s, or even films of very thin thickness, without observing excessive wear on the surface of the applicator cylinder.
• the direct transfer mode generates defects in the surface appearance of the coating deposited on the strip called stringing or lineage, defects which are all the more marked when the application is made at high speed or at thin thickness. .
• the object of the present invention is to remedy the drawbacks of the processes of the prior art by providing a process for continuously coating strips which makes it possible to deposit films of formulation in a " wide range of viscosities.
• the invention also has the purpose of providing a process which requires only little adjustment to obtain a film of controlled wet thickness in a wide range of thickness and with a beautiful surface appearance, even when the strip is traveling at high speed.
• the first object of the invention is a process for continuously coating at least one substrate with a film of an organic or mineral formulation in the form of a solution or dispersion, the viscosity of said formulation being included between 0.001 and 100 Pa.s. at room temperature, according to which the process comprises the following stages:
• a rotary cylinder with a deformable surface is rotated, a uniform primary ply of controlled width and thickness of said formulation is formed on the rotary cylinder,
• the entire thickness of the intermediate ply is transferred from the applicator cylinder to the substrate by compressing the applicator cylinder against the substrate to obtain a coating film of uniform thickness.
• the viscosity of the formulation is between 0.001 and 0.01 Pa.s
• the gripper cylinder is rotated in the opposite direction relative to the direction of rotation of the applicator cylinder
• the gripper cylinder is rotated in the same direction of rotation as the direction of rotation of the applicator cylinder, - the clamping force between the cylinder is adjusted taker and the applicator cylinder at a constant value, between 100 and 1000 kg.ms "2 , and chosen as a function of the final thickness of the film and as a function of the viscosity of the formulation, - the tangential speed of the applicator cylinder is adjusted in a ratio between 1 and 2 times the speed of the substrate,
• the applicator cylinder and the take-up cylinder are rotated at an identical tangential speed, - the substrate runs on at least one support,
• the substrate runs in an upward or horizontal stretched strand
• the lower part of the take-up cylinder is immersed in a bath of the formulation in the liquid state, and the rotary drive of the take-up cylinder makes it possible to form thereon a primary tablecloth of the formulation,
• a metering cylinder with a non-deformable surface is brought into contact with the taker cylinder, said dosing cylinder is rotated in opposite direction to the direction of rotation of the taker cylinder, and we introduce , at a controlled flow rate, the formulation in the liquid state at the air gap of the take-up cylinder and of the metering cylinder,
• the substrate is a metal strip or sheet
• the substrate is coated on one or the other or both sides simultaneously or successively, - after the film has been transferred to the substrate, said film is dried and / or hardened by physical means and / or chemical.
• the second object of the invention is a device for continuously coating at least one substrate with a film of an organic or inorganic formulation in the dispersion or solution state, the viscosity of the said formulation being between 0.001 to 100 Pa.s. at room temperature of the type comprising:
• - an applicator cylinder in contact on one side with a pickup cylinder, and on the other side with the moving substrate, according to which: - said applicator cylinder is a cylinder with a non-deformable surface rotated in the opposite direction to the direction of scrolling of said substrate, and - Said cylinder is a cylinder with a deformable surface driven in rotation either in the opposite direction to the direction of rotation of said applicator cylinder, or in the direction of rotation of said applicator cylinder.
• a metering cylinder with a non-deformable surface is in contact with the take-up cylinder, it is rotated in opposite direction to the direction of rotation of said take-up cylinder, and an introduction device for introducing said formulation at a controlled rate and at a temperature, arranged above the air gap of the take-up cylinder and the metering cylinder,
• the lower part of the take-up cylinder is immersed in a bath of said formulation, said bath being contained in a tank fed continuously with the formulation,
• the pick-up cylinder is in contact with a metering roll which is rotated in opposite direction to the direction of rotation of the pick-up cylinder
• FIG. 1 is a schematic sectional view of 'A continuous coating installation according to the invention.
• FIG. 2 is a schematic sectional view of another continuous coating installation according to the invention.
• the invention aims to implement an identical coating process for continuously coating a substrate with a film of conventional paints as well, which may have a viscosity of between 0.01 and 100 Pa.s. at room temperature, only surface treatment solutions, such as aqueous chromating solutions, whose viscosity is of the order of 0.001 to 0.01 Pa.s.
• the formulations according to the invention have a viscosity of between 0.001 and 100 Pa.s at room temperature.
• Formulations with a viscosity of less than 0.001 Pa.s at room temperature could be used, that is to say formulations in which the solvent or dispersant is a volatile organic solvent, for example ether.
• the solvent or dispersant is a volatile organic solvent, for example ether.
• these would not be of great industrial interest due to the volatile nature of the solvent which would require a complete covering of the coating installation, as well as strict safety instructions for operating personnel.
• the use of this type of solvent is not recommended.
• the term “formulation” is intended to mean a formulation either based on at least one polymer, or based on at least one mineral compound, and the solvent or dispersant of which is either organic or aqueous.
• the term “formulations based on at least one mineral compound in the form of a solution or dispersion in water or in an organic solvent” means solutions for treating metal surfaces such as, for example, chromating.
• the formulations in the form of solutions or dispersions in water or in an organic solvent can also usually contain fillers, pigments, catalysts, plasticizers, stabilizers or any other known additive.
• the invention applies not only to metal substrates, such as steel, aluminum or an aluminum alloy, but also to glass, plastic, plywood, or any other suitable material.
• the substrate may have been previously painted or covered with a coating on one or two sides.
• the thickness of the substrate is, for example between 0.1 and 4 mm.
• the substrate is preferably in the form of a strip or sheet.
• FIG. 1 there is shown a strip B supported on at least one support 1 shown by a support cylinder with deformable surface, and driven in travel along the arrow F by drive means (not shown).
• the device according to the invention also comprises a take-up cylinder 2 with a deformable surface in contact on one side with an applicator cylinder 3 with a non-deformable surface, and on the other side with a metering cylinder 4 also with a non-deformable surface.
• the applicator cylinder 3 is kept in contact with the strip B bearing on the support cylinder 1.
• This figure represents a reverse transfer mode in which, according to the invention, the applicator cylinder 3 is rotated, by appropriate means (not shown) in the direction of arrow f1 which is the opposite direction of the direction of travel of the strip B.
• the gripping cylinder 2 is rotated by appropriate means (not shown) in the direction of arrow f2 which is the opposite direction of the direction of rotation of the applicator cylinder 3, while the metering cylinder 4 is rotated, by appropriate means (no shown) in the direction of arrow f3 which is the opposite direction to the direction of rotation of the take-up cylinder 2.
• the cylinders with non-deformable surface are formed by rectified steel cylinders which can be coated with a layer of ceramic or chromium.
• the cylinders with deformable surface are formed of a steel core coated with a layer or an envelope of elastomer or polyurethane.
• the device 6 for introducing the formulation 7 comprises one or more nozzles arranged parallel to the width of the take-up 2 and dosing cylinders 4.
• a device for supplying continuous formulation (not shown) is connected to the introduction device 6 It is equipped with a heating device and a device for homogenizing the formulation.
• the installation also includes a tank 8 placed under the taker 2 and doser 4 cylinders which can be connected to the supply device.
• the formulation 7 is introduced, by gravity, into the air gap 5 of the metering cylinder 4 and of the picking cylinder 2.
• the metering cylinder 4 being driven in rotation opposite to the direction of rotation of the picking cylinder 2, makes it possible to distribute the formulation 7 over the entire width of the take-up cylinder 2 and, to form on the take-up cylinder 2 a uniform primary ply 9 of controlled width and thickness by adjusting the width of the air gap 5.
• the formulation 7 introduced in excess into the air gap 5 flows into the tank 8, and can be reinjected into the supply device 6 where it will be re-homogenized and brought back to temperature.
• a part of the primary ply 9 is transferred from the pick-up cylinder 2 to the applicator cylinder 3 by compressing the primary ply 9 formed between the pick-up cylinder 2 and the applicator cylinder 3.
• the primary ply 9 is divided, sharing it in a controlled manner when the primary ply 9 leaves the contact zone between the taker 2 and applicator 3 cylinders, to obtain an intermediate ply 10 which is transferred to the applicator cylinder 3.
• the other part of the primary ply 9 is driven by the gripper cylinder 2.
• the gripper 2 and applicator 3 cylinders are rotated, preferably at identical tangential speeds, and the clamping force between the gripper 2 and applicator 3 cylinders is adjusted to a constant value, chosen as a function of the final thickness of the film 11 which one wishes to deposit on the strip, and as a function of the viscosity of the formulation 7.
• This clamping force is between 100 and 1000 kg. m. s "2 .
• the clamping force between the gripping cylinders 2 and applicator 3 is less than 100 kg.ms "2 , then the cylinders are not sufficiently compressed.
• the deformable envelope of the gripping cylinder 2 does not deform sufficiently, and it reveals its imprint on the primary water table 9.
• Formulation 7 is preferably used at room temperature, and not at a temperature above 40 ° C., so as to avoid any risk of the formulation starting to cook, or of evaporation of the solvent, which would not allow more control of the thickness of the plies 9, 10 and of the film 11.
• the entire intermediate ply 10 is transferred from the applicator cylinder 3 to the strip B by compressing the strip B between the support cylinder 1 and the applicator cylinder 3 to obtain a film 11 controlled thickness.
• an overspeed is applied to the applicator cylinder 3 relative to the speed of the band B, by adjusting the tangential speed of the applicator cylinder 3 in a ratio of between 1 and 2 times the speed of the band B. If, adjusts the tangential speed of the applicator cylinder 3 in a ratio less than once the speed of the strip B, then the transfer of the intermediate ply 10 onto the strip B is not carried out under optimum conditions, because the strip B will tend to repel the tablecloth 10.
• the tangential speed of the applicator cylinder 3 is adjusted in a ratio greater than 2 times the speed of the strip B, then the transfer of the intermediate ply 10 onto the strip B takes place without problems.
• the inventors have found that by using certain types of paint (such as latex paints), the film 1 1 deposited on the strip B had a poor surface appearance, with in certain cases appearance of the defect of stringing or line. . This is why, the overspeed on the applicator cylinder 3 is limited relative to the speed of the strip B in a ratio which does not exceed 2.
• this film 1 1 also depends on the roughness of the applicator cylinder 3, in fact the greater this is, the thicker the film 11 deposited. This roughness is chosen by the operator during the machining of the applicator cylinder 3 and degrades very little during coating.
• the strip B is thus coated with a film 11 of wet formulation with a thickness of between 1 and 250 ⁇ m.
• the film 11 is dried and / or hardened by physical and / or chemical means, known in themselves.
• the coated strip BR passes through a hot air or induction furnace (not shown), or even under UV lamps or under a device diffusing electron beams (not shown), so as to drying and / or hardening the film 11.
• the strip BR is thus coated with a film of formulation 7 with a thickness of between 1 and 240 ⁇ m, depending on the dry extract contained in formulation 7.
• Figure 1 there is shown a first embodiment in which the transfer mode between the gripping cylinder 2 and the applicator cylinder
• the mode of transfer between the take-up cylinder and the applicator cylinder can be reverse.
• the gripping cylinder is rotated in the same direction as the direction of rotation of the applicator cylinder.
• the dosing cylinder is always rotated in the opposite direction to the direction of rotation of the taker cylinder.
• a primary ply is formed on the take-up cylinder.
• all of this primary ply is transferred to the applicator cylinder, compressing the picking cylinder against the applicator cylinder to obtain an intermediate ply on the applicator cylinder.
• the entire intermediate ply is transferred to the strip to obtain a film of controlled thickness.
• This embodiment gives the coated strip a very good surface appearance (good tension of the coating), and is especially used for applying paint films comprising metallic fillers of the glitter type which make it possible for example to obtain a seed appearance.
• the installation may not include a metering cylinder.
• the strip runs in an upward or horizontal stretched strand, that is to say that the strip is held by deflector rollers situated upstream of the strip contact area and of the applicator cylinder and downstream of the drying of the coating applied.
• the total transfer of the intermediate ply from the applicator cylinder to the strip is carried out by compressing the applicator cylinder against the strip.
• the strip and the applicator cylinder are slightly nested so as to increase the contact area between the strip and the applicator cylinder and thus promote the transfer of the intermediate ply to the strip.
• the device for introducing the formulation is not necessary, because the tank 8 ′ is filled with a bath 12 ′ of the formulation 7 ′ fed continuously with this formulation 7 'by a supply device (not shown).
• the lower part of the take-up cylinder 2 ' is immersed in the bath 12', and the rotary drive of the take-up cylinder 2 'makes it possible to form thereon a primary ply 9' of the formulation 7 'whose thickness is controlled by adapting the rotation speed of the gripping cylinder 2 'and / or the clamping force between the gripping cylinders 2' and applicator 3 '. If, as shown in FIG.
• the gripping cylinder 2 ' is rotated in the opposite direction to the direction of rotation of the applicator cylinder 3', the primary ply 9 'is transferred to the applicator cylinder 3' in the same way as in the first embodiment described. If on the contrary, the gripping cylinder 2 'is rotated in the same direction of rotation as the direction of rotation of the applicator cylinder 3', the intermediate ply 10 'is transferred to the applicator cylinder 3' in the same manner as in the second embodiment described.
• a system with at least three cylinders, comprising a metering cylinder, a gripping cylinder and an applicator cylinder.
• the lower part of the metering cylinder is immersed in the bath, then the primary ply is transferred to the taker cylinder either in reverse transfer mode, or in direct transfer mode according to the respective directions of rotation of these two cylinders, then we transfer the intermediate layer on the applicator cylinder as we have seen previously.
• the speed of rotation of the metering cylinder is adjusted to a value low enough to avoid splashing, and the speed of rotation of the picking cylinder is adjusted to a higher speed so as not to slow down the speed of the line.
• the number of cylinders brought into contact between the applicator cylinder and the metering cylinder can vary, so as to gradually increase the transfer speed of the primary ply of a cylinder to an adjacent cylinder. This guarantees a high line speed while avoiding splashing.
• the duration of use of the applicator cylinder according to the invention is much greater than that of the applicator cylinder of the prior art. This allows, in addition to significant productivity gains (no relining of the cylinders, reduction in the number of cylinder changes), improving operator safety due to the reduction in cylinder handling,
• the thickness of the coating is easily controlled and remains constant along the strip (slight degradation of the roughness of the applicator cylinder during use of the device, application in reverse transfer mode),

Applications Claiming Priority (3)

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• 2002
  • 2002-10-04 FR FR0212379A patent/FR2845299B1/fr not_active Expired - Fee Related
• 2003
  • 2003-09-25 EP EP03798948A patent/EP1551567B1/de not_active Expired - Lifetime
  • 2003-09-25 DE DE60316710T patent/DE60316710T2/de not_active Expired - Lifetime
  • 2003-09-25 WO PCT/FR2003/002816 patent/WO2004030831A2/fr active IP Right Grant
  • 2003-09-25 AU AU2003276371A patent/AU2003276371A1/en not_active Abandoned
  • 2003-09-25 ES ES03798948T patent/ES2291742T3/es not_active Expired - Lifetime
  • 2003-09-25 AT AT03798948T patent/ATE374653T1/de active

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