Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
  • C23C2/22—Removing excess of molten coatings; Controlling or regulating the coating thickness by rubbing, e.g. using knives, e.g. rubbing solids
• • 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
  • B05C1/0826—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 the work being a web or sheets
  • B05C1/083—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 the work being a web or sheets being passed between the coating roller and one or more backing 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
  • B05C1/0826—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 the work being a web or sheets
  • B05C1/0834—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 the work being a web or sheets the coating roller co-operating with other rollers, e.g. dosing, transfer 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
  • 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

Definitions

• the present invention relates to a method and a device for continuously coating at least one metal strip with a fluid film of small thickness of crosslinkable polymer free of solvent or non-reactive diluent.
• thermosetting polymers for example thermosetting polymers, or physically, such as, for example, photopolymerizable polymers, are known.
• thermosetting organic coatings that are continuously applied to metal substrates.
• these are complex formulations that associate in a solvent or aqueous medium a system of functional organic prepolymer binders, a crosslinking system and additives such as pigments or fillers, various formulation adjuvants.
• thermoplastic or thermosetting organic coating to a bare or coated metal strip.
• organic coatings such as for example liquid paints or varnishes is most often carried out by roller coating of these liquid coatings as a solution or dispersion in a solvent or aqueous medium.
• the liquid coating is deposited on a metal strip by pre-dosing the solution or dispersion by means of a two or three-roll system and transferring part or all of the liquid coating thus pre-stressed to a applicator roll in contact with the surface of the metal strip to be coated.
• the transfer is carried out either by friction of the applicator roll and the metal strip, the scrolling of the two contacting surfaces being effected in the opposite direction or by contact in the same direction.
• extrusion coating of a thin organic coating is routinely practiced especially with thermoplastic polymers on flexible surfaces, such as paper, plastic films, textiles or even thin metal substrates such as packaging materials.
• the application of the molten coating is carried out by means of a rigid flat die or a nozzle positioned in direct contact with the substrate.
• the pressure exerted by the die on the substrate results from the viscosity of the melt.
• the possibilities of correcting unevenness of the substrate by plating it on the support roll are very limited.
• This coating extrusion technique requires perfect parallelism between the edges of the die and the substrate and this substrate must be either perfectly flat or deformable to allow the formation of a thin deposit of uniform thickness.
• the deposited material thickness is controlled by the play and pressure between the die and the substrate, which imposes a perfect parallelism of these two elements when one wants to achieve very thin applications.
• the technique of extrusion lamination of a uniform layer of fluid coating on a substrate uses die drawing of a fluid web at the exit of a flat die, which web is then pressed onto the substrate using for example a cold roller, a rotating bar or by an air knife or an electrostatic field.
• the thickness of the fluid web is controlled by the flow rate of the material in the die section and the substrate speed.
• the plating pressure must, however, be small enough to avoid the formation of a calender bead and, therefore, this transfer mode does not make it possible to compensate for possible variations in thickness and unevenness in the case of a rigid substrate.
• This technique for applying the coating with formation of a free strand at the extrusion die exit avoids the problems of coupling between the die and the rigid substrate, but it induces instabilities of application if the length free strand fluctuates and is difficult to implement with thermosetting systems with a viscosity of less than 2000 Pa.s because of the difficulties in achieving regular stretching and good plating.
• the continuous application of a thin organic coating on metal substrates is carried out under low contact pressures, insufficient to allow a thin coating, uniformly and homogeneously applied on rigid substrates which may have flatness and thickness heterogeneity defects.
• microbubbles of air can be interposed between the coating and the substrate which affects the homogeneous application and the surface appearance of this coating.
• the polymer coating after crosslinking, the polymer coating must be sufficiently hard while being deformable to allow the shaping of the sheets thus coated without causing degradation or detachment of the coating.
• the increase in the molecular weight of the precursors has a very unfavorable effect on the viscosity of a solvent-free polymer or a non-reactive diluent, which is detrimental to the ease of transfer and application of the web to the state. melted uncrosslinked on the metal strip.
• EPC discloses a process for continuously coating at least one metal strip with a crosslinkable polymer-free solvent-free or diluent-thick film and a thickness less than that of the metal strip, in which the metal strip is continuously scrolled, said metal strip is preheated to a temperature substantially equal to or greater than the temperature of the crosslinkable polymer fluid film and the softening temperature of this crosslinkable polymer a homogeneous sheet of uniform thickness of said crosslinkable polymer is formed by forced flow on a hard surface gripping cylinder, said gripping cylinder being heated to a temperature substantially equal to or greater than the temperature of said sheet and at the temperature of softening of this crosslinkable polymer and rotated in the same direction as the support roll of the metal band allique and form the crosslinkable polymer film to a uniform thickness substantially equal to the desired thickness, and is compressed between the gripper cylinder and the metal strip, a deformable surface applicator element, heated to a
• the aim of the invention is to avoid these drawbacks by proposing a method and a device for continuously coating at least one metal strip with a fluid film of small thickness made of crosslinkable polymer that is free of solvent or non-reactive diluent and whose the softening temperature is greater than 50 ° C, to obtain a coating of uniform thickness of a few microns to a few tens of microns applied in a homogeneous manner on this strip, while avoiding that microbubbles of air are inserted between the film and the metal strip and overcoming flatness and roughness defects of this band and by allowing an application on part or all of the coating and this despite variations in width and transverse positioning of this band.
• FIGs. 1 and 3 schematically shows two installations for continuously coating a metal strip 1 with a fluid crosslinkable polymer film, free of solvent or non-reactive diluent and having a thickness for example between 5 and 50 .mu.m.
• This metal strip 1 has a thickness for example between 0.10 and 4 mm and is for example steel or aluminum or aluminum alloy and can be coated or prepainted on one or both sides.
• the polymer used to coat the metal strip 1 is a solvent-free polymer or non-reactive and thermally crosslinkable diluent such as a thermosetting polymer or physically such as a photopolymerizable polymer.
• This polymer has in the uncrosslinked state a softening temperature greater than 50 ° C.
• These polymers have different softening, start-flow, start-cross-cure and crosslinking temperatures.
• the crosslinking start temperature is the temperature from which an increase in viscosity of greater than 10% is observed in less than 15 minutes.
• the metal strip 1 is driven in scrolling along the arrow F and the metal strip 1 is supported on at least one support cylinder 3.
• the installations comprise means 2 for preheating the metal strip 1 at a temperature substantially equal to or greater than the temperature of the crosslinkable polymer fluid film to deposit said metal strip 1 and the softening temperature of this crosslinkable polymer.
• the means 2 for preheating the metal strip 1 are constituted for example by at least one induction furnace.
• the cooking means comprise for example at least one induction furnace and cooling means and in the case where the polymer is physically crosslinkable, the cooking means may be constituted by ultraviolet lamps or by electron beams.
• the crosslinkable polymer film to be deposited on the metal strip 1 must be of uniform thickness, although this metal strip 1 has thickness heterogeneities or flatness defects as well as roughness and / or significant surface ripples. amplitudes equal to or greater than the thickness of the film to be deposited on the metal strip 1.
• the forced flow forming means of the crosslinkable polymer ply 30 comprise, for example, an extrusion machine, not shown, of conventional type, provided with a spinneret 11 comprising an extrusion slot 12 and a flow control member, not shown, constituted for example by a metering pump and disposed between the extrusion machine and the die 11.
• the formation and total transfer means in thickness of the film 31 of crosslinkable polymer are formed by the cylinder 20 and by means for compressing the metal strip 1 between the cylinder 20 and the support cylinder 3 for obtain a coating of uniform thickness.
• a transfer is considered to be total or almost total thickness when more than 90% of the material has been transferred.
• the cylinder 20 is heated to a temperature substantially equal or greater, on the one hand, to the formation temperature of the web 30 and, on the other hand, to the softening temperature of the crosslinkable polymer and is rotated, by means of appropriate means not shown, in a reverse direction in the direction of travel of the metal strip 1, as represented by the arrows f1 in Figs. 1 and 2.
• the cylinder 20 comprises a metal core coated with an envelope of deformable material, such as an elastomer, and the support cylinder 3 has a hard surface.
• the cylinder 20 has a hard surface and the support cylinder 3 comprises a metal core coated with an envelope of deformable material such as an elastomer.
• the formation of the web 30 of said crosslinkable polymer is carried out for example by extrusion coating or by extrusion lamination.
• the means for forming by forced flow of the sheet 30 are formed by the die 11 bearing against the surface of the cylinder 20 and provided with means of adjustment, of the conventional type, the position of the edges of the extrusion slot 12 of said die 11 relative to the surface of the cylinder 20.
• the die 11 of the extrusion machine gives the uniform distribution of the ply 30 which is obtained by adjusting the flow rate of the die 11 and the speed of rotation of the cylinder 20.
• the die 11 is supported on the cylinder 20 for example by means of cylinders, not shown, the pressure of which makes it possible to standardize the leakage rate of the fluid crosslinkable polymer.
• the means for forming by forced flow of the ply 30 are formed by the die 11, means for drawing the ply 30 by adjusting the flow rate of this spinneret 11 and / or the speed of rotation of the applicator roll 20, adjustment means of the conventional type, the position of the edges of the extrusion slot 12 of said die 11 relative to the surface of the cylinder 20 and by means of means, not shown, for plating the ply 30 on said surface of the applicator roll 20.
• the plating means of the ply 30 on the surface of the cylinder 20 are formed for example by an air knife directed towards this cylinder 20 at the generatrix of contact of said ply 30 on said applicator cylinder 20.
• the cylinder 20 and the support cylinder 3 each comprise a hard surface and the transfer element is formed by a transfer cylinder 21 or applicator cylinder comprising a metal core coated with a casing of deformable material, such as an elastomer.
• the cylinder 20 and the support cylinder 3 each comprise a metal core coated with an envelope of deformable material, such as for example an elastomer, and the transfer element is formed by an applicator roll 21 of hard surface.
• the transfer element is formed by an endless band.
• the cylinder 20 heated to a temperature substantially equal to the formation temperature of the web 30 and the softening temperature of the crosslinkable polymer, is rotated in the opposite direction to the running direction of the metal strip.
• the applicator cylinder 21 heated to a temperature substantially equal to or greater than the temperature of the cylinder 20 is rotated also in the opposite direction to the direction of travel of the support cylinder 3 of the metal strip 1, as represented by FIG. arrow f2 in FIG. 3 and 4.
• the thermal conditioning of the crosslinkable polymer during the contact of the sheet 30 on the cylinder 20 in the case of the first embodiment shown in Figs. 1 and 2 or during the contact of the intermediate web 30b on the cylinder 20 and / or the contact of the film 31 on the transfer element 21 in the case of the embodiment shown in Figs. 3 and 4, to lower the viscosity of this crosslinkable polymer, can be achieved in different ways.
• the heat-conditioning means of the crosslinkable polymer are formed by an internal heating system of the cylinder 20 and / or the applicator cylinder 21 and / or by at least one source 15 for applying a heat flux. complementary to the ply 30 or to the intermediate ply 30b and / or to the film 31.
• the thermal conditioning means of the crosslinkable polymer are formed by an internal heating system of the cylinder 20 and / or by an external heating system of the applicator roll 21 and / or by at least one source 15 of applying a complementary thermal flux to the ply 30 or to the intermediate ply 30b and / or to the film 31.
• the internal heating system of the cylinder 20 and / or the applicator cylinder 21 is constituted by electrical resistances embedded in the mass of each of said cylinders or by channels formed in said cylinders for the circulation of a coolant, such as for example oil.
• the temperature of these cylinders must be adjusted, for example by means of a not shown thermocouple, in order not to exceed a limit value to avoid damaging the outer envelope of deformable material by too high a temperature and to deteriorate the bonding layer between the deformable material and the metal core of said cylinders.
• this heating system is arranged facing the corresponding cylinder in the zone not covered by the film 31 and is consisting for example of hot air generators or infrared lamps.
• the source or sources of application of the complementary heat flux on the film 31 or on the intermediate layer 30b and / or on the film 31 consist for example of infrared lamps of medium absorption wavelength between 1 , 5 and 4 ⁇ m or by hot air generators or by microwave systems.
• the heat-conditioning means of the cross-linkable polymer in suitable modalities therefore make it possible to lower the viscosity of this polymer, ie the fluidity of the polymer, in order to facilitate its transfer and its application on the metal strip 1.
• the modalities are adapted to lower the viscosity of the crosslinkable polymer by at least a factor of 2, and for the temperature of said crosslinkable polymer to exceed the crosslinking start temperature of this polymer.
• this viscosity retains at least transiently a very low level facilitating the transfer and the application of the film 31 crosslinkable polymer on the metal strip 1.
• the coating device 10 comprises means, not shown, of conventional type, for adjusting the tangential speeds of the cylinder 20 or the cylinder 20 and the applicator roll 21 in a ratio between 0.5 and 2 times the running speed of the metal strip 1.
• the speeds of the cylinder 20 or the cylinder 20 and the applicator roll 21 can be adjusted independently of one another.
• the coating device 10 also comprises means (not shown) for adjusting the contact pressure between the cylinder 20 and the metal strip 1 (FIGS 1 and 2) and, on the one hand, between the cylinder 20 and the cylinder applicator 21 and, on the other hand, between the applicator roll 21 and the metal strip 1 (Figs 3 and 4).
• These means consist, for example, of hydraulic cylinders or screw / nut systems which make it possible to adjust the contact pressures as a function of the viscosity of the crosslinkable polymer so as to ensure a total transfer of the material and to minimize the friction forces. .
• the extrusion slot 12 of the die 11 and the cylinder 20 or the cylinder 20 and the applicator roll 21 have a length greater than the width of the metal strip 1 so as to coat the entire surface of the face of this metal strip 1 in contact with the cylinder 20 or the applicator cylinder 21.
• the extrusion slot 12 of the die 11 and the cylinder 20 or the cylinder 20 and the applicator roll 21 may have a length less than the width of the metal strip 1 to coat only part of the surface the face of said metal strip 1 in contact with the cylinder 20 or the applicator roll 21.
• the application of the thin and thin film 31 of thermally or physically crosslinkable polymer is carried out as follows.
• the metal strip 1 is maintained at a temperature equal to or greater than the softening temperature of the crosslinkable polymer and the cylinder 20 is rotated in the opposite direction to the running direction of this metal strip 1.
• the metal strip 1 is preheated to a temperature of 140 ° C immediately before passing on the support cylinder 3 and scrolls at a speed of 30m / min.
• the sheet 30 formed by forced flow at a temperature above the softening temperature of the crosslinkable polymer in the uncrosslinked state is pressed onto the cylinder 20 so as to form the film 31 of crosslinkable polymer of uniform thickness substantially corresponding to the thickness of the coating to be formed on the metal strip 1.
• the metal strip 1 thus coated passes into the cooking means 5, then into the cooling means 6 of the film 31 of crosslinkable polymer.
• the application of the thin and thin film 31 of thermally or physically curable polymer is carried out as follows.
• the metal strip 1 is maintained at a temperature equal to or greater than the softening temperature of the crosslinkable polymer in the uncrosslinked state and the rolls 20 and 21 are rotated in a direction opposite to the running direction of the metal strip 1.
• the sheet 30 formed by forced flow at a temperature above the softening temperature of the crosslinkable polymer is pressed onto the cylinder 20 so as to form the intermediate layer 30b of polymer crosslinkable of uniform thickness.
• the intermediate web 30b is transferred from the roll 20 to the applicator roll 21 which forms the film 31 and this film 31 is transferred from the applicator roll 21 on the surface of the metal strip 1 to be coated.
• the metal strip 1 thus coated passes into the cooking means 5, then into the cooling means 6 of the film 31 of crosslinkable polymer.
• the crosslinkable polymer film 31 may be deposited on a bare metal strip of steel or aluminum or aluminum alloy or on a pre-coated or prepainted metal strip.
• the coating thus produced on the metal strip 1 has for example a thickness of between 5 and 50 ⁇ m with a uniformity of thickness of a few microns and this despite the notable defects of flatness or thickness heterogeneity of the metal strip 1.
• the means for forming by forced flow of the sheet 30 may be formed by a rigid block of crosslinkable polymer applied under controlled pressure to deposit crosslinkable polymer particles on the cylinder 20 and form said sheet 30 or by a transfer system under an electrostatic field of a polymer powder crosslinkable on the cylinder 20 to form this web 30.
• the means for forming by forced flow of the ply 30 may be formed by a fluid crosslinkable polymer spraying system on the cylinder 20 or by an application system on this cylinder 20 of a continuous strip. crosslinkable polymer previously produced to form said web 30.
• the means for forming by forced flow of the sheet 30 may be formed by a rotating bar disposed between the die 12 and this cylinder 20.
• the web 30 and the cross-linkable polymer film 31 may have a width less than the width of the metal strip 1 to coat a part of this metal strip 1 or a width greater than the width of this metal strip 1 to coat the entire of said metal strip 1.
• This excess cross-linkable polymer must be removed in order to prevent it from creating an excess thickness on the cylinder 20 or on the applicator roll 21.
• the coating device 10 is equipped with means 40 for removing the excess crosslinkable polymer deposited on the cylinder 20.
• the means 40 for removing the excess crosslinkable polymer deposited on the cylinder 20 are formed by two scraped, respectively 41a and 41b, for example metal, in contact with the cylinder 20 in each zone located outside the zone in contact with the cylinder 20 with the metal strip 1.
• doctor blades 41a and 41b in contact with the cylinder 20 are arranged upstream of the generatrix for applying the ply 30 to this cylinder 20 with respect to the direction of rotation of said cylinder 20.
• the transverse position of the rades 41a and 41b on the cylinder 20 may be secured, by appropriate means, not shown, to the width of the metal strip 1 and / or to the transverse position of this metal strip 1 on the support cylinder 3.
• this metal strip 1 on the support cylinder 3 may vary.
• doctor blades 41a and 41b are thus in contact with the cylinder 20 and remove the excess of crosslinkable polymer by friction on said cylinder 20.
• the means 40 for removing the excess crosslinkable polymer on the cylinder 20 may be formed by two recovery cylinders arranged between the scrapers 41a and 41b and the cylinder 20.
• the means for removing the excess crosslinkable polymer on the cylinder 20 may be formed by a recovery cylinder interposed between the cylinder 20 and a doctor blade having a length at least equal to the length of the cylinder 20 .
• the means 40 for removing the excess crosslinkable polymer deposited on the cylinder 20 are formed by at least one squeegee, for example metal, in contact with the cylinder 20.
• the means 40 for removing the excess crosslinkable polymer deposited on the cylinder 20 are formed by two doctor blades, respectively 42a and 42b, for example metal, each in contact with the lateral edge of the cylinder 20 upstream of the generator for applying the ply 30 to this cylinder 20.
• the transverse position of the doctor blades 42a and 42b on the cylinder 20 is secured by appropriate means, not shown, to the width of the metal strip 1 and / or to the transverse position of this metal strip 1 on the support cylinder 3.
• doctor blades 42a and 42b are thus in contact with the cylinder 20 and remove the excess of crosslinkable polymer by friction on said cylinder 20.
• the second solution consists in equipping the applicator cylinder 21 with means 40 for removing the excess crosslinkable polymer.
• these means 40 for removing the crosslinkable polymer excess on the applicator roll 21 are formed by a recovery cylinder 22 in contact with the applicator roll 21, and by at least one squeegee 43 in contact with said recovery roll 22 .
• the excess crosslinkable polymer deposited on the applicator cylinder 21 is transferred to the recovery cylinder 22 because of the pressure exerted by said recovery cylinder on the applicator cylinder 21 and this excess crosslinkable polymer is removed from the recovery cylinder 22 by the squeegee 43.
• the means for removing the excess crosslinkable polymer on the applicator roll 21 may be formed by a recovery cylinder 22 and by two scrapes each in contact with a lateral edge of said recovery cylinder 22.
• the means for removing the excess crosslinkable polymer deposited on the cylinder 20 or the applicator roll 21 avoids having to add inserts at the slot 12 of the extrusion die 11 so as to calibrate as soon as leaving the die 12 the web 30 of crosslinkable polymer and to accommodate variations in width and transverse positioning of the metal strip 1 within the predefined tolerance limits.
• the point of application of the film 31 of the crosslinkable polymer may be located at a different location than in front of the support cylinder 3 of the metal strip 1 and, for example, on a free arm stretched by this metal strip 1 downstream of said support cylinder 3.
• the two faces of the metal strip 1 can be coated with a film 31 of crosslinkable polymer.
• a device 10 for applying the film 31 is disposed on one side of the metal strip 1 and another film application device 31 is disposed on the other side of said metal strip 1.
• the application of the film 31 on each side of the metal strip 1 may be shifted or simultaneous.
• the support cylinder 3 is removed and replaced by an applicator cylinder of the second application device.
• the applicator roll of each device forms a support cylinder of the metal strip.
• the transverse position of the extrusion die 11 may be permanently centered with respect to the metal strip 1 by arranging this extrusion die 11 on a transversely movable support and by connecting this die to the extrusion machine by a flexible which makes it possible to slave the position of this extrusion die 11 with respect to the metal strip 1 as a function of the variations of the transverse position of said metal strip 1 relative to the cylinder of the support 3.
• a lubricant may be deposited on the applicator roll 20 outside the zone in contact with the metal strip 1 so as to facilitate the operation of the squeegees 41a and 41b for the removal of the excess of crosslinkable polymer.
• This mixture is entirely in the fluid and / or viscous state starting from a temperature equal to 120 ° C. and its rapid cross-linking temperature is between 170 ° and 250 ° C.
• the crosslinkable polymer may also be pigmented and loaded, for example, with 40% and more by weight of titanium oxide.
• This value causes rapid wear of the applicator roll.
• the coating device according to the invention makes it possible to obtain a cross-linkable polymer coating with a uniform thickness of, for example, between 5 and 50 ⁇ m and homogeneously applied to a metal strip having a large roughness of amplitude comparable to that of film thickness and this thanks to the perfect contact between the applicator roll and the surface of the metal strip to be coated, despite the defects of flatness and thickness heterogeneity of the metal strip.
• the speed of the applicator roll can be adjusted to a level substantially greater or less than the running speed of the metal strip so as to obtain a perfect continuity of the coating and an excellent surface state of this crosslinkable polymer coating transferred onto this metal strip.
• the surface energy of the applicator roll is adapted to the crosslinkable polymer to allow good spreading of the web on the applicator roll.
• the coating device according to the invention can also be used for a downward or horizontal metal strip.
• thermosetting polymers Since the forced flow through an extrusion slot involves significant stagnation of the polymer which are necessary for a good distribution of this polymer over the entire width of this extrusion slot and it should not risk at this level a crosslinking of said polymer.
• the coating device according to the invention makes it possible to continuously coat metal strips of different widths or to coat simultaneously several metal strips arranged parallel to each other and to overcome by simple and effective means fluctuations in width and transverse positioning of the metal strip or strips.
• the coating device according to the invention makes it possible to facilitate the regular and uniform supply of the crosslinkable polymer coating by selecting the most appropriate mode of supply according to the product to be used.
• the temperature of the material delivered by the supply system located upstream of the applicator cylinder is limited to a value lower than that of the beginning of crosslinking to avoid any risk of evolution of the product in the feed system and any risk of blockage of this system.
• this device also makes it possible, in the case of a chemical transfer process, to raise the temperature of the crosslinkable polymer so as to reduce its viscosity and to facilitate its transfer and spreading on the metal strip. .
• the material can withstand a very large heating, but for a very short time that avoids any risk of crosslinking the product at this level.
• the device according to the invention makes it possible to compensate for variations in the width or transverse position of the metal strip during application and to overcome the defects of uniformity of the metal strip and thus to make a coating of Uniform surface thickness on a non-uniform metal substrate.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Coating Apparatus (AREA)
• Laminated Bodies (AREA)

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• 1999
  • 1999-12-07 DK DK99957371T patent/DK1140375T3/da active
  • 1999-12-07 WO PCT/FR1999/003040 patent/WO2000035593A1/fr active IP Right Grant
  • 1999-12-07 EP EP99957371A patent/EP1140375B1/fr not_active Expired - Lifetime
  • 1999-12-07 AT AT99957371T patent/ATE249287T1/de not_active IP Right Cessation
  • 1999-12-07 CA CA002355383A patent/CA2355383C/fr not_active Expired - Fee Related
  • 1999-12-07 PT PT99957371T patent/PT1140375E/pt unknown
  • 1999-12-07 JP JP2000587895A patent/JP2002532231A/ja active Pending
  • 1999-12-07 DE DE69911245T patent/DE69911245T2/de not_active Expired - Fee Related
  • 1999-12-07 BR BR9916098-6A patent/BR9916098A/pt not_active Application Discontinuation
  • 1999-12-07 ES ES99957371T patent/ES2207309T3/es not_active Expired - Lifetime
  • 1999-12-07 AU AU15098/00A patent/AU765280B2/en not_active Ceased
  • 1999-12-07 KR KR1020017007543A patent/KR100598709B1/ko not_active IP Right Cessation
  • 1999-12-09 US US09/857,976 patent/US6562407B1/en not_active Expired - Fee Related

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