Classifications

• • 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
  • D21H23/52—Addition to the formed paper by contacting paper with a device carrying the material
  • D21H23/56—Rolls
  • D21H23/58—Details thereof, e.g. surface characteristics, peripheral speed
• • 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
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
• • 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
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/10—Oxides, borides, carbides, nitrides or silicides; Mixtures thereof
  • C23C4/11—Oxides
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49544—Roller making
  • Y10T29/4956—Fabricating and shaping roller work contacting surface element
  • Y10T29/49563—Fabricating and shaping roller work contacting surface element with coating or casting about a core

Definitions

• the present invention relates to a coating bar for the paper industry.
• the coating bar or rod is used in the paper industry to bring a coating material (or "sauce") generally on cardboard or paper to make a cardboard or coated paper.
• the coating bar consists of a metal rod having a diameter generally between 10 and 20 mm.
• the sleeping bar is generally held in any support such as a polymer sheath, also called a bed, in which it can rotate.
• the coating bar in turning, constitutes in a way a doctor blade which removes the excess coating material or "sauce” on the paper, the dosage of the coating material or obtaining a desired thickness of material on the paper, being obtained by varying the pressure of application of the coating bar on the paper and / or by varying the speed of rotation.
• Coated paper is a strong paper added value and generally of very high quality, the paper being obtained by depositing two or three layers of coating material on each side.
• the machines include four and even more coating heads. It follows that intensive use of the coating bars in the manufacturing machines leads to rapid wear of the said bars, said wear being accelerated when using a pigmented coating material due to the high abrasion of the pigments on the bars. Sleeping. The consequence of this rapid wear is that it is necessary to change the coating bars of each machine every two days. As the machines currently each comprise eight coating bars, it is easy to measure the economic impact of the coating bars on papermaking.
• the object of the present invention is to propose a smooth or grooved coating bar whose lifespan has been considerably increased, by at least 50%.
• An object of the present invention is to produce a coating bar which is coated with a coating constituted by a mixture of ceramics, said coating having a wetting or wetting angle between 30 ° and 90 ° and a porosity of less than 5%, the size of the pores not exceeding 5 ⁇ m.
• the behavior of the coating material may vary from one situation to another. Indeed, it has been found that it is necessary that the surface tension between the transfer cylinder and the coating material should be greater than the surface tension existing between said coating material and the coating bar, if we want all or almost all of the coating material contained, for example, in the hollow of the grooves is transferred. Therefore, if the wettability of the coating of the coating bar is not sufficient, then there is a dry friction between the coating and the coating material; if the wettability is too high, then at least part of the coating material remains on the coating, for example in the bottom of the grooves. In the latter case, the grooves no longer play their metering role perfectly since a certain amount of coating material remains trapped in the bottom of the grooves.
• the wetting angle or wettability of the coating is between 30 ° and 90 ° and preferably between 60 ° and 85 °.
• the wettability of the coating of the coating bar is modified, by varying certain parameters of said coating, such as the porosity or pore size, the structure of the coating, for example within the network of ceramic mixture used to constitute said coating. Since the coating may consist of grains of ceramics juxtaposed, it will be preferable, in certain cases, to vary the concentration or molar content of the ceramics used in the mixture.
• the present invention recommends using in said mixture a main constituent whose molar content is between 40 and 60%.
• the coating is obtained by spraying onto the coating bar, a powder of agglomerated ceramic grains or of sintered or split agglomerated grains ground with a size of each agglomerate less than
• the particle size of the sprayed powder is less than 80 ⁇ m and preferably between 10 and 45 ⁇ m.
• the coating thus obtained has a thickness of between 15 and 60 ⁇ m and a porosity of less than 5% with an average pore size of less than 5 ⁇ m.
• the preferred ceramics according to the invention are chosen from Cr 2 O 3 , MgO, Al 2 O 3 , TiO 2 , SiO 2 and ZrO 2 .
• a particular mixture consists of 50% Cr 2 O 3 and 50% MgO.
• Another particular mixture of ceramics has the following composition, in moles: 48% Al 2 O 3 ,
• Torch power 30 KW, Intensity: 600 A,
• Powder flow rate of the mixture 32 g / min, Rod rotation speed: 500 rpm
• Torch movement speed 50 mm / second.
• the coating bar is maintained at a temperature below 50 ° C by means of a CO 2 jet for example.
• the final coating obtained according to the invention has a certain surface roughness which it is necessary to largely eliminate in order not to alter the surface condition of the finished coating bar.
• a treatment is applied to the coated coating bar so as to obtain a surface roughness of less than 1 ⁇ m.
• the surface treatment may for example be wet polishing.
• Another treatment consists in placing the coating bar in a rubber roller or between two rubber rollers which rotate on the coating bar, the coating bar-rubber roller assembly being immersed in a slip loaded with 50% by volume. CaCO 3 , TiO 2 or other grain but whose diameter is less than one nanometer.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Coating By Spraying Or Casting (AREA)
• Paper (AREA)
• Glass Compositions (AREA)
• Coating Apparatus (AREA)
• Liquid Crystal Substances (AREA)
• Materials For Medical Uses (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9512694

Family Applications (1)

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Cited By (1)

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Family Cites Families (24)

• 1997
  • 1997-10-27 FR FR9713450A patent/FR2770234B1/fr not_active Expired - Fee Related
• 1998
  • 1998-10-27 DE DE69801338T patent/DE69801338T2/de not_active Expired - Fee Related
  • 1998-10-27 JP JP2000518126A patent/JP3553877B2/ja not_active Expired - Fee Related
  • 1998-10-27 EP EP98952799A patent/EP1027470B1/de not_active Expired - Lifetime
  • 1998-10-27 WO PCT/FR1998/002299 patent/WO1999022040A1/fr not_active Ceased
  • 1998-10-27 AT AT98952799T patent/ATE204027T1/de not_active IP Right Cessation
• 2000
  • 2000-04-26 US US09/560,651 patent/US6666807B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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