EP3178654A1 - Rakel - Google Patents

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Publication number
EP3178654A1
EP3178654A1 EP15199303.7A EP15199303A EP3178654A1 EP 3178654 A1 EP3178654 A1 EP 3178654A1 EP 15199303 A EP15199303 A EP 15199303A EP 3178654 A1 EP3178654 A1 EP 3178654A1
Authority
EP
European Patent Office
Prior art keywords
coating
doctor
squeegee
hard material
material particles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP15199303.7A
Other languages
German (de)
English (en)
French (fr)
Inventor
Hans Jörg BRUDERMANN
Michael Reinert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daetwyler Swisstec AG
Original Assignee
Daetwyler Swisstec AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daetwyler Swisstec AG filed Critical Daetwyler Swisstec AG
Priority to EP15199303.7A priority Critical patent/EP3178654A1/de
Priority to CA3005691A priority patent/CA3005691C/en
Priority to EP16819023.9A priority patent/EP3386753B1/de
Priority to BR112018011159-7A priority patent/BR112018011159B1/pt
Priority to JP2018549613A priority patent/JP2019500250A/ja
Priority to MX2018006423A priority patent/MX2018006423A/es
Priority to CN201680071650.2A priority patent/CN108367565B/zh
Priority to PCT/EP2016/080473 priority patent/WO2017097995A1/de
Priority to US15/776,001 priority patent/US10953649B2/en
Priority to PL16819023T priority patent/PL3386753T3/pl
Priority to ES16819023T priority patent/ES2784689T3/es
Publication of EP3178654A1 publication Critical patent/EP3178654A1/de
Priority to HK18112096.8A priority patent/HK1252795A1/zh
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F9/00—Rotary intaglio printing presses
    • B41F9/06—Details
    • B41F9/08—Wiping mechanisms
    • B41F9/10—Doctors, scrapers, or like devices
    • B41F9/1072—Blade construction

Definitions

  • the invention relates to a squeegee comprising a squeegee body having a working edge, and a first squeegee side, which faces a printing cylinder in particular during operation, and a second squeegee side, which faces away from the printing cylinder in particular during operation, wherein the squeegee body provided with a coating comprising a polymer is, wherein the coating comprises particles at least in a partial area. Furthermore, the invention relates to a method for producing such a doctor.
  • Squeegees are used in the printing industry as well as in papermaking.
  • scrapers are used, in particular, for scraping off excess printing ink from the surfaces of printing cylinders or printing rollers.
  • the quality of the squeegee has a decisive influence on the print result. Unevenness or irregularities of the standing with the impression cylinder working edges of the doctor blade lead z. B. to incomplete stripping of the ink from the webs of the printing cylinder. This can lead to an uncontrolled release of ink on the print carrier.
  • the working edges of the doctor are pressed during stripping to the surfaces of the impression cylinder or pressure rollers and are moved relative to these.
  • the working edges especially in rotary printing machines, on the one hand exposed to high mechanical loads, which bring a corresponding wear with it - on the other hand, high demands are placed on the working edges of the doctor, so that over a very long period of application, a precise stripping is ensured.
  • Squeegees are therefore basically consumables, which must be replaced periodically.
  • Squeegees are usually based on a squeegee body made of steel or plastic with a specially shaped working edge.
  • the working edges of the doctor blade can also be provided with coatings or coatings of plastics, paints and / or metals.
  • the material properties of the coatings in particular have a significant influence on the mechanical and tribological properties of the doctor blade.
  • Such squeegees are known in the art.
  • Such a squeegee is used for example in the EP 0 911 157 B1 described.
  • This relates to a doctor blade for doctoring superfluous ink from the surface of a printing plate.
  • the lamella and also the region of the rear doctor blade part adjoining the lamella are provided over the entire doctor blade length with a coating consisting of lubricant or at least having lubricant particles.
  • the coating may comprise a carrier material in which both lubricant particles and particles of a wear-resistant material are embedded.
  • doctor blades are also referred to as doctor blades, doctor blades or scrapers, depending on the application.
  • a doctor or doctor blade e.g. superfluous coating color (for example, pigments, binders, additives, etc.) are removed from a paper substrate or a paper web.
  • superfluous coating color for example, pigments, binders, additives, etc.
  • the life of the doctor blades, doctor blades or scrapers can be improved by providing the working edges of the doctor blade with coatings or coatings of plastics, paints and / or metals.
  • the object of the invention is to provide a squeegee belonging to the technical field mentioned above, which can be used as advantageously as possible at low production costs for applications in the printing industry or in papermaking.
  • the doctor should be suitable for applications in the printing industry and allow the most accurate possible inking.
  • the particles are formed as hard material particles and a mass fraction of Hard material particles in the coating on the first doctor blade side is higher than a mass fraction of the hard material particles in the coating on the second doctor blade side.
  • the first squeegee side in particular the side facing the printing cylinder, comprises at least the contact area between squeegee and pressure roller or paper substrate during an application, for example during the doctoring of printing ink.
  • the second squeegee side in particular the side of the squeegee facing the printing cylinder, comprises the surface of the squeegee, which encloses an angle of less than 90 ° with a tangent on the pressure roller or on the paper substrate, in the area of contact with the squeegee.
  • the side of the squeegee facing the printing substrate or the paper substrate is that surface of the squeegee which can be reached directly, that is without passage through the squeegee, through an extended radius of the printing roll or paper substrate.
  • the radius corresponds to a surface normal of the paper substrate.
  • a doctor blade body having a working edge in a doctor blade body having a working edge, a first doctor blade side, which in particular faces the printing cylinder during operation, and a second doctor blade side, which faces away from the printing cylinder in particular during operation, are coated with a coating comprising a polymer, which comprises particles at least in a partial area.
  • the particles are formed as hard material particles and a mass fraction of the hard material particles in the coating on the first doctor blade side is higher than a mass fraction of the hard material particles in the coating on the second doctor blade side.
  • squeegee is to be understood in the present case and includes both squeegees for applications in the printing industry as well as in the paper industry.
  • the squeegees are squeegees, doctor blades, doctor blades and / or scrapers.
  • the squeegee is a squeegee, which is provided in particular for doctoring off of printing ink from a printing cylinder.
  • the squeegee body preferably has an elongate shape and may, for example, be in the form of a band, the working edge being oriented in a longitudinal direction of the band. ever for strength, material and dimensions of the doctor body this may be present as a roll of tape, for example.
  • the coating comprising a polymer preferably comprises more than 50% by weight (weight percent) of polymers, in particular more than 75% by weight of polymers, particularly preferably more than 90% by weight of polymers. Further, the polymer content is preferably less than 99% by weight, more preferably less than 95% by weight. Polymers are thus preferably the main constituent of the coating.
  • the abovementioned proportions of the polymers in the coating are based on the coating of the ready-to-use doctor blade.
  • the coating comprising the polymer may, prior to application to the doctor blade body due to solvents or other volatile substances, a lower mass fraction of hard material particles than on the doctor blade body in the ready-to-use state of the doctor blade. By a drying step during manufacture of the doctor blade, such volatiles can be removed.
  • the polymer comprises or consists in the present case in particular of an organic polymer.
  • the polymer may be a homopolymer or a copolymer.
  • Homopolymers consist essentially of a single type of monomer, while copolymers consist of two, three or more chemically different types of monomers. It is also possible that the polymer is in the form of a so-called polymer blend or as a mixture of several different homopolymers and / or copolymers.
  • the polymer is a thermoset, thermoplastic and / or an elastomer.
  • Preferred are e.g. Thermosets.
  • Thermosets have a three-dimensional cross-linking after hardening and usually can not be deformed after they have hardened.
  • suitable polymers include epoxy resins, phenolic resins such as phenol-formaldehyde resins (novolaks and resoles), melamine-formaldehyde resins, and saturated and unsaturated polyester resins or mixtures thereof.
  • the polymers may further comprise rubber, polyurethanes, polyureas, thermoplastics or mixtures thereof.
  • the thermoplastics may, for example, acrylonitrile butadiene styrene, Polyamide, polycarbonate, polyethylene, polypropylene, polystyrene, polyvinyl chloride or mixtures thereof.
  • the skilled worker is also aware of other possible polymers which may be provided in pure form or as mixtures for the production of the coating.
  • the polymer mixtures may in particular comprise two or more different polymers.
  • the coating may also comprise less than 50% by weight of polymer.
  • the hard material particles typically serve to improve the wear behavior of the doctor, but can also bring about other effects.
  • the hard material particles are preferably dispersed in a coating in which also the polymer or the polymers are contained.
  • the hard material particles are advantageously distributed uniformly in the coating on the first doctor blade side and on the second doctor blade side.
  • the coating thus has a heterogeneous structure due to the dispersed hard material particles.
  • the coating can be sprayed, sprayed, rolled, painted or otherwise applied to the doctor body, for example as a lacquer.
  • the two doctor blade sides of the doctor blade have coatings with different mass fractions of hard material particles.
  • the hard particles can occur there in larger concentrations, where increased stress on the doctor blade is expected.
  • the hard material particles can be used in an economical manner, in particular since the hard material particles are preferably represented to a greater extent in the region of the greatest stress on the doctor, so that hard material particles can be saved in the less heavily stressed areas of the doctor blade.
  • the manufacturing costs can be kept low at substantially constant quality of the doctor blade.
  • the other rackel side has a higher homogeneity and improved adhesion to the doctor blade body. Overall, in particular, a more uniform wear of the coating of the doctor blade can be achieved.
  • the first doctor blade side which in particular faces the printing cylinder or the paper during operation, preferably comprises an end face of the working edge, which in operation rests on the printing cylinder or on a paper substrate.
  • This allows the coating be provided with the higher mass fraction of hard particles exactly where the highest stress of the doctor blade takes place.
  • the coating with the higher mass fraction of hard material particles can also extend further on the first side and, in particular, also cover the entire first doctor blade side.
  • the coating with the higher mass fraction of hard material particles covers at least the front side of the working edge and thus at least a portion of the first doctor blade side, preferably more than 20%, more preferably more than 50%, more preferably more than 70% of the surface the first squeegee side.
  • the coating covers at least the entire working edge. More preferably, the coating covers in addition to the working edge another, peripheral to the working edge portion of the doctor.
  • the second doctor blade side comprises in particular the side facing away from the printing cylinder or the paper during operation.
  • a transition between the first squeegee side and the second squeegee side coatings may be fused, for example, applying both coatings before subjecting the squeegee to a drying process at a temperature above the flow point of the coatings.
  • the two coatings of the first and the second doctor blade side can also be overlapping, in this case an overlapping region is preferably located on the side facing away from the printing cylinder during operation, so that the quality of the doctor blade during operation is not impaired. Under certain circumstances, however, the overlap can also be smoothed out in a thermal process step.
  • both sides can be coated with a coating having the lower mass fraction of hard material particles (respectively without hard material particles), whereupon the first doctoring side is coated in a second step with a coating having the larger mass fraction of hard material particles.
  • the skilled worker is also aware of other methods for achieving the doctor blade sides of different hard material particle mass fractions.
  • the coated according to the invention doctor have a high wear resistance and accordingly a long life. Furthermore, the working edges of the inventive doctor blade are well stabilized. This results in a sharply limited Contact zone between the squeegee and the impression cylinder or the pressure roller, which in turn allows accurate ink stripping. The contact zone remains largely stable over the entire printing process. Also, the banding during the break-in phase in the printing process is low. Overall, hardly any effects affecting the printing process are caused.
  • the doctor according to the invention therefore makes it possible to achieve a substantially constant printing quality during the entire printing process. Also advantageous are the doctor in applications in the paper industry, for example as a doctor blade.
  • the doctor according to the invention have good sliding properties on the printing cylinders or printing rollers commonly used, so that wear of the printing cylinders or printing rollers can be reduced when using the doctor according to the invention. This also applies to sliding properties on paper.
  • a ratio of the mass fraction of the hard material particles in the coating on the first doctor blade side to the mass fraction of the hard material particles in the coating on the second doctor blade side is in particular greater than 2, preferably greater than 10, particularly preferably greater than 100, in particular greater than 1000.
  • the ratio of the mass fraction of the hard material particles in the coating on the first doctor blade side to the mass fraction of the hard material particles in the coating on the second doctor blade side is, for example, in the range from 2: 1-1000: 1, in particular 10: 1-100: 1.
  • the coating of the first doctor side comprises hard material particles, while the coating of the second doctor side is substantially free of hard material particles.
  • substantially free of hard material particles is to be understood that, if hard particles were present, they have no or no significant effect on the wear resistance of the doctor.
  • a small proportion of hard material particles can nevertheless be introduced into the second squeegee side, in particular in the form of impurities.
  • a mass fraction of less than 1%, preferably less than 0.1%, more preferably less than 0.05% is particularly preferably, the coating of the second doctor blade side has no hard material particles.
  • the second doctor blade side can have a substantial proportion of hard material particles, which thus positively influences the wear resistance of the doctor blade.
  • the coating of the second doctor blade side has a lower mass fraction of hard material particles than the first doctor blade side.
  • the coating of the second doctor blade side comprises no particles.
  • the second doctor blade side preferably does not comprise any hard material particles, but also no further particles, which may influence, for example, the sliding friction or other properties of the doctor blade. Since the second squeegee side is subjected to significantly lower mechanical stresses, it may be sufficient if only the first squeegee side comprises particles. It has been found that the wear resistance of the doctor blade is generally independent of the type of coating of the second doctor blade side. A coating of the second doctor blade side, for example with a polymer paint without particles, may still be useful, for example, to protect the doctor blade surface from corrosion or even from aesthetic aspects.
  • the coating of the second doctor blade side may be provided with particles. These can influence, for example, the strength, the sliding properties or other properties of the doctor blade.
  • an average volume-equivalent spherical diameter of the hard material particles is less than 1'000 nanometers, preferably less than 500 nanometers, particularly preferably less than 250 nanometers.
  • the particle size of the hard material particles is advantageously adapted to the particular material of the hard material particles.
  • the volume-equivalent spherical diameter indicates the diameter of a sphere with the same volume as the particles or hard material particle considered. If the particles are porous, the volume of a particle preferably corresponds to the volume of an outer shell of the particle. Below the average of this value is preferred understood the median grain size distribution. In the following, the term "particle size" is used, but the average volume-equivalent spherical diameter is meant.
  • an arithmetic mean of the ball diameter can be used instead of the median or instead of the volume equivalent ball diameter a surface equivalent ball diameter can be determined.
  • the tribological properties of the inventive doctor blade can be optimized. It has been found that the doctor blades with hard material particles in these orders of magnitude have an excellent wear behavior with an optimum contact zone between doctor blade and printing cylinder or paper substrate.
  • the particle sizes can also be selected larger than 1'000 nanometers. However, if the layer thickness is too low, this can have a negative effect on the quality of the contact zone between doctor blade and printing cylinder or paper substrate.
  • the average volume-equivalent spherical diameter of the hard material particles is greater than 1 nm, particularly preferably greater than 25 nm, more preferably greater than 50 nm. It has been found that optimal wear resistance of the doctor blade can be achieved. Smaller ball diameters may also be considered, depending on the thickness of the coating.
  • a volume fraction of the hard material particles is preferably 5 to 30%, more preferably 15 to 20%. With such proportions, a significant improvement in the wear properties and the stability of the working edge is achieved.
  • the hard material particles preferably dispersed in the coating may in particular be metals, metal oxides, metal carbides, metal nitrides, metal carbonitrides, metal borides, ceramics and / or intermetallic phases.
  • the hard material particles particularly preferably comprise at least one of the following substances: metal oxides, in particular aluminum oxide and / or chromium oxide; Diamond, silicon carbide, metal carbide, metal nitride, metal carbonitride, boron carbide, cubic boron nitride, tungsten carbide. These materials have been found to be particularly effective for improving the wear performance of the coating, particularly in the context of the coating comprising a polymer.
  • the coating can comprise exactly one type of hard material particles.
  • the hard material particles contain different particles of at least two different materials. As it has been shown, this synergetic effects can be caused, which improve the wear resistance and quality of the doctor much more than expected. Furthermore, it may be advantageous if the hard material particles comprise different particles having at least two different average particle sizes.
  • organometallic particles as an additional component to improve the Verschleiss s the doctor possible.
  • other metal nitrides, metal carbonitrides, metal borides, ceramics and / or intermetallic phases can also be provided as the hard material particles.
  • the hard material particles may also comprise metal particles. Suitable z. As metal particles of W, Ti, Zr, Mo, and / or steel. The person skilled in the art is familiar with further metals which can be processed into hard material particles. The metal particles can be used alone, in combination with other metal particles and / or in combination with other hard material particles. Furthermore, hard material particles of metal alloys can be used.
  • Metal particles of metallic molybdenum have proven particularly suitable. Squeegees with a coating based on polymers with dispersed metal particles made of molybdenum have a very high resistance to wear and, correspondingly, a long service life. The working edges of such doctor blade in this case have a sharply defined contact zone between the doctor blade and the printing cylinder or the pressure roller, which allows a more accurate ink stripping.
  • the metal particles have an average volume-equivalent spherical diameter of 0.01-0.9 ⁇ m and a volume fraction of 5-30%, particularly preferably 15-20%.
  • Doctor blades with a polymer-based coating with metal oxides, metal carbides, metal nitrides, metal carbonitrides, metal borides, ceramics and / or intermetallic phases dispersed therein have a high wear resistance and, correspondingly, a long service life, especially in combination with a polymer-containing or polymer-based coating.
  • Such hard particles can be embedded extremely stable in the coating and form a durable composite with the doctor body.
  • the strength of the coating as a whole can be improved, and at the same time, the working edges of such doctor blade on a sharply defined contact zone between the doctor blade and the impression cylinder or the pressure roller, which in turn allows a more accurate ink stripping.
  • metal carbides and / or metal nitrides have been found to be particularly suitable: B 4 C, cubic BN, TiC, WC and / or SiC.
  • metal oxides Al 2 O 3 is particularly advantageous.
  • the hard material particles need not necessarily be in the form of metal particles, metal oxides, metal carbides, metal nitrides, metal carbonitrides, metal borides, ceramics and / or intermetallic phases. Basically come as hard particles and particles of other materials in question.
  • the hard material particles comprise diamond. Preference is given to using diamond with mono- and / or polycrystalline structure. Hard particles made of diamond have proven to be particularly advantageous in the inventive doctor and bring in particular a further improvement of the wear resistance and stabilization of the working edges of the doctor with him. This is probably due to the high hardness and the chemical and mechanical stability of diamond.
  • amorphous diamond-like carbon As has been shown, however, it is possible in principle to use particles of amorphous diamond-like carbon ("DLC") instead of or in addition to diamond particles of mono- and / or polycrystalline structure.
  • DLC amorphous diamond-like carbon
  • the amorphous diamond-like carbon advantageously has a high proportion of sp3 hybridization, so that sufficient hardness is achieved.
  • amorphous diamond-like carbon may even have advantages. In general, amorphous diamond-like carbon is also less expensive than diamond.
  • the hard material particles comprise both SiC and diamond, more preferably a particle size of the SiC being greater than a particle size of the diamond.
  • the hard material particles comprise SiC with a particle size of 0.7-0.9 ⁇ m and diamond with a particle size of 5 nm-0.9 ⁇ m, preferably 200-300 nm.
  • the hard material particles comprise, for example, both SiC and cubic BN, with a particle size of the BN preferably corresponding approximately to the particle size of the SiC.
  • the particle sizes of the SiC and the cubic BN measure about 0.1-0.9 ⁇ m.
  • the coating to improve the wear resistance lubricant in particular lubricating particles comprises.
  • lubricating particles are basically substances in question, which cause a reduction in the sliding friction between doctor blade and impression cylinder and are particularly stable enough, so that no impairment or contamination of the printing cylinder occurs.
  • polymeric thermoplastics for example, polymeric thermoplastics, z.
  • a well-suited lubricant is, for example, polytetrafluoroethylene (PTFE).
  • PTFE polytetrafluoroethylene
  • Polytetrafluoroethylene is preferably used in the form of lubricating particles.
  • Hexagonal BN has also proven particularly advantageous as a lubricant. This particular in particle form. It has been found that lubricants, particularly hexagonal BN lubricating particles, have improved the blade's wear resistance in a variety of different cylinder applications. This particular largely independent of the process parameters when doctoring. In other words, hexagonal BN has proven to be an extremely versatile and effective lubricant.
  • Lubricating particles in particular lubricating particles of hexagonal BN, advantageously have a particle size of 50 nm-0.9 ⁇ m, preferably 80-300 nm, more preferably 90-110 nm. As a result, an optimal effect is achieved for a large number of applications. In principle, however, other particle sizes may also be suitable for specific applications.
  • lubricants as additives for improving the wear resistance, are present in the coating.
  • lubricating particles as well as hard material particles.
  • lubricating particles of hexagonal BN are used together with hard particles of SiC.
  • the coating comprises, in addition to the hard material particles, fibers for reinforcing the coating.
  • the fibers may include, for example, carbon fibers, plastic fibers or the like.
  • a layer thickness of the coating is preferably 1 to 30 ⁇ m (microns). More preferably, the layer thickness is 5 - 20 microns, more preferably 5 - 10 microns. Such layer thickness provide optimum protection of the working edge of the doctor. In addition, such a measured layer thickness has a high intrinsic stability, which effectively reduces the partial or complete delamination of the first coating, for example during the doctoring of printing ink from a printing cylinder.
  • thicknesses of less than 1 ⁇ m are possible, the wear resistance of the working edge or the doctor blade decreases rapidly. Greater thicknesses than 30 microns are also feasible. However, these are generally less economical and may also negatively affect the quality of the working edge. However, thicknesses of less than 1 .mu.m or more than 30 .mu.m can be quite advantageous for special application areas of the doctor blade.
  • the squeegee body is formed of a metal or a metal alloy.
  • squeegee bodies made of metals which are robust and corrosion-resistant.
  • squeegee bodies made of aluminum are particularly advantageous.
  • doctor blade bodies can also be made of other metals, for example iron, etc.
  • the doctor blade can also be made of a metal alloy, whereby the desired properties of the doctor blade can be optimally controlled.
  • the choice of material of the doctor blade body is preferably matched to the coating such that an optimal wear resistance of the doctor blade and thus a maximum possible life achieved, and a precise doctoring are possible.
  • the squeegee body is made of steel.
  • Steel has proven to be a particularly robust and suitable material for the doctor according to the invention in mechanical terms. This allows precise squeegees with a long service life can be produced inexpensively.
  • At least one jacket region of the main body which is present with respect to the longitudinal direction is completely and completely covered by a coating.
  • a coating As a result, at least the working edge, the upper side, the lower side and the rear edge of the main body opposite the working edge are covered with a coating.
  • the side surfaces of the main body that are perpendicular to the longitudinal direction may be uncoated.
  • the second coating covers the base body completely and on all sides, that is to say that the side surfaces of the base body which are perpendicular to the longitudinal direction are also covered with one of the coatings. In this case, at least one of the coating completely surrounds the main body.
  • the essential areas of the main body which do not belong to the working edge are also provided with the coating.
  • This is particularly advantageous in order to protect the main body from the water-based or slightly acidic printing inks and / or other fluids coming into contact with the doctor blade.
  • base bodies made of steel so optimal rust protection for the doctor blade is created.
  • the constancy of the print quality during the printing process is further improved, since the printing cylinder or printing roll in contact with the doctor blade during the printing process is not contaminated by rust particles, for example.
  • the base body is best protected against rust formation by a coating applied in the jacket area during storage and / or transport.
  • the doctor blade is only coated where the greatest mechanical stress occurs, namely at the working edge and its peripheral regions.
  • the coating can be kept inexpensive.
  • This variant is particularly advantageous in the case of doctor bodies, which are essentially chemically inert, in particular to the field of application of the doctor blade.
  • squeegee bodies made of stainless steel or aluminum may possibly not be coated only in the region of the working edge or on the side facing away from the printing cylinder during operation. This can reduce the material costs during production.
  • doctor blade body is formed from a plastic or from a plastic material.
  • plastic base bodies have proved to be more advantageous than steel base bodies because of their different mechanical and chemical properties.
  • some of the plastics in question have sufficient chemical stability or inertness to typical water-based and slightly acidic printing inks, which means that the base body does not need to be specially protected, as in the case of a steel base body.
  • plastics are inexpensive to buy and easy to work with.
  • plastics are easier and therefore also to be preferred in the application, in particular in the handling of the maintenance of printing presses and the like.
  • Plastic squeegees continue to exhibit good coating properties with a polymer-based coating.
  • the squeegee body not only purely adhesive as the squeegee of metal, but optionally also chemically bonded to the coating or thermally fused with the coating in a boundary phase.
  • plastic material z. B polymer materials in question. These may be, inter alia, thermoplastic, thermosetting and / or elastomeric polymer materials. Suitable plastics are z. As polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl alcohol, polyethylene terephthalate, polyamide, polyacetal, polycarbonate, polyarylate, polyetheretherketone, polyimide, polyester, polytetrafluoroethylene and / or polyurethane. Composite structures with fibers to reinforce the polymer matrix are also possible. In principle, however, basic body can be used which z. B. consist of both metal, especially steel, as well as plastic. Also basic body with other materials, eg. As ceramics and / or composite materials, may be suitable for specific applications, where appropriate.
  • the squeegee body is heated prior to coating.
  • a coating later dissolves the doctor blade body for example by corrosion of the doctor blade body under the coating.
  • the polymer-based coating therefore has a lower viscosity on the doctor blade, with the result that the coating can be distributed uniformly without the formation of streaks or drops.
  • the coating material to be applied comprises solvents, this can further promote the drying process.
  • heating of the squeegee body prior to coating can also be dispensed with.
  • the doctor blade body is preferably degreased mechanically and / or electrolytically before the coating. Preferred is an electrolytic degreasing. In turn, an optimal connection between the coating and the doctor body is achieved. Impurity present on the squeegee, particularly greasy contamination, can deleteriously interfere with the adhesion between coating and squeegee body.
  • the electrolytic degreasing can also be dispensed with.
  • another cleaning step may be used, for example, a washing step with a washing solution such as an organic solvent or a soap solution.
  • the squeegee for electrolytic degreasing is connected as an anode to remove grease by means of cations from the doctor body.
  • anodic degreasing oxygen is formed on the doctor body under the fat layer, which dissolves the fat layer.
  • the anodic degreasing has the advantage over the cathodic degreasing that hydrogen embrittlement is avoided can.
  • the increased power requirement compared to the cathodic degreasing is therefore deliberately taken into account especially in squeegees made of steel in order to protect the squeegee body.
  • the degreasing can alternatively be carried out with exchanged electrodes, as cathodic degreasing.
  • This has the advantage that twice the gas volume can be generated by the formation of hydrogen under the fat layer with the same amount of electricity.
  • the hydrogen embrittlement must be accepted.
  • cathodic degreasing can be easily selected to obtain more efficient degreasing with less power consumption. Furthermore, both techniques can be applied sequentially.
  • a drying step takes place, wherein in particular the drying step is followed by a hardening step.
  • any solvents present in the coating can be gently removed, while in the hardening step even the smallest residual amounts of solvents are removed and the structure of the coating is cured.
  • the hardening step may be purely thermal, that is, for example, the coating with or on the doctor body baked.
  • the hardening step can also initiate a chemical process. This may include, for example, a polymerization initiated by UV rays. The skilled worker is also aware of other such steps which may be followed by a polymer-based coating.
  • drying step and / or the hardening step can also be dispensed with.
  • the hardening step is carried out at a temperature of 150 ° C to 350 ° C, preferably at 200 ° C to 300 ° C, especially at 230 ° C to 270 ° C.
  • these temperatures are held for a holding time of 0.5 to 15 hours, preferably 0.5 to 8 hours.
  • Such temperatures and hold times have been found to be optimal to achieve sufficient hardness of the coatings.
  • Temperatures of less than 100 ° C are also possible. In this case, however, very long and mostly uneconomical holding times are required. Higher temperatures than 350 ° C, depending on the material of the base body and the coating, in principle feasible, but it is important to ensure that in particular the polymer-containing coating is not damaged by the hardening step.
  • the coating is subjected to an aftertreatment.
  • an aftertreatment is particularly preferably a mechanical aftertreatment and / or a cleaning.
  • a mechanical treatment may be performed, such as grinding, lapping or polishing the coating or a treatment using suitable tools, such as knives, milling cutters or the like.
  • the aftertreatment can also be dispensed with
  • a slat blade 100 according to the invention is shown in contact with a pressure roller 170 in cross-section.
  • the lamella blade 100 includes a base body 110 made of steel, which on the in Fig. 1 left side has a rear portion 120 having a substantially rectangular cross-section.
  • the rear region 120 is provided as a fastening region in order to hold the lamellar blade, for example in a corresponding receiving device of a printing press.
  • a doctor blade thickness, measured from the top 121 to the bottom 122 of the rear area, is about 0.2 mm.
  • a length of the base body 110 or of the lamella blade 100 measured perpendicular to the plane of the sheet is, for example, 1000 mm.
  • the pressure roller 170 may have a clockwise or counterclockwise direction of rotation 171. For applications in flexo printing both directions of rotation are possible. In gravure printing, the platen is rotated clockwise in the present arrangement.
  • FIG. 1 On the in Fig. 1 right side of the base body 110 is tapered step-like from the top 121 of the rear portion 120 to form a working edge 130 forth.
  • An upper side 131 of the working edge 130 lies on a plane below the plane of the upper side 121 of the rear region 120, but is essentially parallel or plane-parallel to the upper side 121 of the rear region 120.
  • the lower side 122 of the rear region 120 and the lower side 132 of the working edge 130 lie in a common plane, which is plane-parallel to the upper side 121 of the rear region 120 and plane-parallel to the upper side 131 of the working edge 130.
  • a width of the main body 110 measured from the end of the rear area to the front side 140 of the working edge 130, measures for example, 40 mm.
  • a thickness of the working area 130 measured from the upper side 131 to the lower side 132 of the working area, is for example 0.060-0.150 mm, which corresponds to approximately half the thickness of the squeegee in the rear area 120.
  • a free end face 140 of the free end of the working edge 130 extends from the top 131 of the working edge 130 obliquely down to the bottom 132 of the working edge 130 back.
  • the end face 140 has an angle of approximately 45 ° or 135 ° with respect to the upper side 131 of the working edge 130 or with respect to the lower side 132 of the working edge 130.
  • An upper transition region between the upper side 131 and the front side 140 of the working edge 130 is rounded.
  • a lower transition region between the end face 140 and the bottom 132 of the working edge 130 is rounded.
  • the working edge 130 of the lamella blade 100 is further surrounded by a coating 150.
  • the coating 150 completely covers the upper side 131 of the working edge 130, the transition region 125 and a subregion of the upper side 121 of the rear region 120 of the main body 110 adjoining this.
  • the coating 150 covers the end face 140, the underside 132 of the working edge 130 and a subregion of the underside 122 of the rear region 120 of the base body 110 adjoining the underside of the working edge 130.
  • the coating 150 is a polymer-based coating, for example, the coating comprises epoxy resin, wherein the epoxy resin content in the ready-to-use coating is, for example, about 70 or 80 wt.%, Depending on the side of the doctor (see below).
  • Therein are hard material particles 160, z. B. of silicon carbide (SiC), dispersed.
  • An average particle size of the hard material particles 160 is about 0.8 ⁇ m.
  • the layer thickness of the first coating 150 measures in the region of the working edge 130 z. B. 15 microns. In the region of the upper side 121 and the lower side 122 of the rear region 120, the layer thickness of the first coating 150 continuously decreases, so that the first coating 150 ends in a wedge shape in a direction away from the working edge 130.
  • the mass fraction of hard material particles 160 in the coating of the pressure roller facing the first side of the doctor blade 100 is higher than in the coating of the pressure roller facing away from the second side of the doctor.
  • the first side comprises the front side 140 and the lower side 132 of the working edge 130.
  • the second side comprises the upper side 131 of the working edge 130.
  • the mass fraction of hard material particles 160 in the first side coating is, for example, 20% by weight and the mass fraction of epoxy resin is in the coating of the same side, for example 70% by weight.
  • the mass fraction of hard material particles 160 in the coating of the second side is, for example, 10% by weight and the mass fraction of epoxy resin in the coating of the same side is, for example, 80% by weight.
  • the second side of the doctor blade 100 has a lower content of hard material particles 160 than the first side of the doctor blade 100.
  • the first side that is to say the side facing the pressure roller 170, thus comprises the contact region between the doctor blade 100 and the pressure roller 170, namely the end surface 140. Furthermore, the first side also comprises the surface 122 of the doctor blade which has a tangent in the contact region of the doctor blade Angle less than 90 ° includes.
  • the same interpretation applies to the following Figures 2 and 3 ,
  • Fig. 2 shows a second inventive blade squeegee 200 in cross section.
  • the second lamella blade 200 has a main body 210 with a rear region 220 and a working edge region 230 and is substantially identical in construction to the first lamella blade 100 Fig. 1 ,
  • the upper side 231 of the working edge 230, the transition region 225 and an adjoining thereto portion of the top 221 of the rear portion 220 of the body 210 and the end face 240, the bottom 232 of the working edge 230 and one to the bottom 232nd the working edge 230 subsequent portion of the bottom 222 of the rear portion 220 of the body 210 with a coating 250 coated.
  • the coating 250 again consists of a polymer-based coating, for example phenol-formaldehyde resin.
  • the coating of the first side of the squeegee 200 facing the pressure roller comprises hard material particles 260, while the coating of the second side of the squeegee facing away from the pressure roller is neither substantially does not comprise a hard material particle.
  • the first side again comprises the front side 240 and the lower side 232 of the working edge 230.
  • the second side comprises the upper side 231 of the working edge 230.
  • the hard material particles are, for example, cubic B 4 C.
  • the ready-to-use coating has a content of phenol-formaldehyde resin of, for example, 80% by weight. Further, the first side coating comprises a cubic B 4 C content of 15% by weight.
  • the second side of the doctor blade 200 has a phenol-formaldehyde resin content of, for example, 95% by weight.
  • the second side of the squeegee 200 is substantially free of particles.
  • An average particle size of the hard material particles 260 is about 0.6 ⁇ m.
  • the layer thickness of the first coating 250 measures in the region of the working edge 230 z. B. 17 microns.
  • Fig. 3 shows a third inventive blade squeegee 300 in cross section.
  • the third squeegee 300 has a main body 310 which protrudes in the region of the working edge 330 in the same way as the first squeegee Fig. 1 coated with a coating 350.
  • the upper side 331 of the working edge 330, the transition region 325 and an adjoining subregion of the upper side 321 of the rear region 320 of the base body 310 and the end face 340, the bottom 332 of the working edge 330 and a subsequent to the bottom 332 of the working edge 330 portion the underside 322 of the rear portion 320 of the base body 310 coated with the coating 350.
  • the coating 350 which completely surrounds the lamella blade 300.
  • the coating 350 completely covers both the upper side 321 and the lower side 322 of the rear region 320 of the main body 310.
  • the coating 350 in turn consists of a polymer-based coating, for example polyamide.
  • the coating of the first side of the squeegee 300 facing the pressure roller comprises hard material particles 360, while the coating of the second side of the squeegee facing away from the pressure roller has no or substantially no Hard material particle includes.
  • the first side in turn comprises the end face 340 and the bottom 332 of the working edge 330.
  • the second side comprises the top 331 of the working edge 330.
  • the hard material particles are, for example, tungsten particles.
  • the ready-to-use coating has a content of polyamide of, for example, 85% by weight. Furthermore, the coating of the first side comprises a content of tungsten particles of 8% by weight.
  • the second side of the doctor blade 300 has a phenol-formaldehyde resin content of, for example, 93% by weight. The second side of the squeegee 200 is again substantially free of particles.
  • An average particle size of the hard material particles 360 is about 0.3 ⁇ m.
  • the layer thickness of the first coating 350 measures in the region of the working edge 330 z. B. 12 microns.
  • Lamellar squeegee shown are only to be understood as illustrative examples of a variety of feasible embodiments.
  • Fig. 4 illustrates a method 400 for producing a lamellar blade, as z.
  • the doctor blade is electrolytically degreased in a first step 401.
  • the squeegee 100 is switched to the electrolytic degreasing as an anode to remove grease from the squeegee body 110.
  • Anodic electrolytic degreasing avoids hydrogen embrittlement.
  • the squeegee body 110 is heated.
  • a coating is carried out with the polymer-based coating material in which the hard material particles and optionally further particles are dispersed and / or other auxiliaries are introduced.
  • a drying and curing step takes place.
  • the main body 110, 210, 310 of the doctor blade from the Fig. 1-3 also from another material, such. As stainless steel or carbon steel, be made.
  • 3 Basically, the main body of the squeegee from the Fig. 1-3 but also from a non-metallic material, such. As plastics exist. This may be advantageous in particular for applications in flexographic printing.
  • each base body can use a different shape.
  • the basic body can have a wedge-shaped working edge or a non-tapered cross-section with a rounded working edge.
  • the free end faces 140, 240, 3403 of the working edges 130, 230, 330 may for example also be formed completely rounded.
  • the inventive doctor blade from the Fig. 1-3 also be different dimensions.
  • the thicknesses of the working areas 130, 230, 330 measured from the respective tops 131, 231, 331 to the respective bottoms 132, 232, 332 may vary within a range of, for example, 0.040 - 0.200 mm.
  • the coatings of the doctor blade from the Fig. 1-3 further coating components and / or additional substances, such as.
  • additional substances such as metal atoms, non-metal atoms, inorganic compounds and / or organic compounds.
  • different lubricants or substances which influence the hardness of the coating can be provided.
  • the additional substances can also be particulate.
  • squeegees shown can be coated with one or more further coatings.
  • the further coatings may be present in the region of the working edges and / or the rear regions and z.
  • B. improve the wear resistance of the working edges and / or protect the rear area from influences by aggressive chemicals.
  • Any additional coating is preferably likewise polymer-based. In variants but also other types of coatings can be used.
  • novel squeegees have been created, which are characterized by a good wear resistance and throughout the life of a uniform and streak-free ink coating allow and are also inexpensive to manufacture.
  • the squeegees according to the invention can be realized in a wide variety of embodiments, so that they can be specifically adapted to specific uses.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Coating Apparatus (AREA)
  • Screen Printers (AREA)
  • Inking, Control Or Cleaning Of Printing Machines (AREA)
  • Rotary Presses (AREA)
  • Paper (AREA)
  • Printing Plates And Materials Therefor (AREA)
EP15199303.7A 2015-12-10 2015-12-10 Rakel Withdrawn EP3178654A1 (de)

Priority Applications (12)

Application Number Priority Date Filing Date Title
EP15199303.7A EP3178654A1 (de) 2015-12-10 2015-12-10 Rakel
MX2018006423A MX2018006423A (es) 2015-12-10 2016-12-09 Raedera.
EP16819023.9A EP3386753B1 (de) 2015-12-10 2016-12-09 Rakel
BR112018011159-7A BR112018011159B1 (pt) 2015-12-10 2016-12-09 Lâmina raspadora e processo para produção de uma lamina raspadora
JP2018549613A JP2019500250A (ja) 2015-12-10 2016-12-09 ドクタブレード
CA3005691A CA3005691C (en) 2015-12-10 2016-12-09 Squeegee
CN201680071650.2A CN108367565B (zh) 2015-12-10 2016-12-09 刮刀和用于制造刮刀的方法
PCT/EP2016/080473 WO2017097995A1 (de) 2015-12-10 2016-12-09 Rakel
US15/776,001 US10953649B2 (en) 2015-12-10 2016-12-09 Squeegee
PL16819023T PL3386753T3 (pl) 2015-12-10 2016-12-09 Rakiel
ES16819023T ES2784689T3 (es) 2015-12-10 2016-12-09 Racleta
HK18112096.8A HK1252795A1 (zh) 2015-12-10 2018-09-20 刮刀

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP15199303.7A EP3178654A1 (de) 2015-12-10 2015-12-10 Rakel

Publications (1)

Publication Number Publication Date
EP3178654A1 true EP3178654A1 (de) 2017-06-14

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EP15199303.7A Withdrawn EP3178654A1 (de) 2015-12-10 2015-12-10 Rakel
EP16819023.9A Active EP3386753B1 (de) 2015-12-10 2016-12-09 Rakel

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP16819023.9A Active EP3386753B1 (de) 2015-12-10 2016-12-09 Rakel

Country Status (11)

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EP (2) EP3178654A1 (pt)
JP (1) JP2019500250A (pt)
CN (1) CN108367565B (pt)
BR (1) BR112018011159B1 (pt)
CA (1) CA3005691C (pt)
ES (1) ES2784689T3 (pt)
HK (1) HK1252795A1 (pt)
MX (1) MX2018006423A (pt)
PL (1) PL3386753T3 (pt)
WO (1) WO2017097995A1 (pt)

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CN111391488A (zh) * 2020-03-26 2020-07-10 深圳市华星光电半导体显示技术有限公司 刮刀、印刷器具和基板的印刷方法
CN115157859A (zh) * 2022-07-12 2022-10-11 宁波湍流电子材料有限公司 一种层压法制造的油墨刮刀及其制造方法

Citations (2)

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EP0911157A1 (de) * 1997-10-24 1999-04-28 MDC Max Dätwyler Bleienbach AG Rakel zum Abrakeln Überflüssiger Druckfarbe von der Oberfläche einer Druckform
WO2013133762A1 (en) * 2012-03-08 2013-09-12 Swedev Ab Electrolytically puls-plated doctor blade with a multiple layer coating

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US5632668A (en) * 1993-10-29 1997-05-27 Minnesota Mining And Manufacturing Company Method for the polishing and finishing of optical lenses
SE519466C2 (sv) * 2000-12-07 2003-03-04 Swedev Ab Schaber - eller rakelblad med beläggning av nickel innefattandes nötningsbeständiga partiklar och metod vid dess framställning
SE0100505L (sv) * 2001-02-16 2002-07-23 Btg Eclepens Sa Självjusterande blad
JP2004034301A (ja) 2002-06-28 2004-02-05 Nikka Kk ドクターブレードおよびその製造方法
EP1745862A1 (en) * 2005-07-21 2007-01-24 C.B.G. Acciai S.r.l. Doctor blade coated with a polymeric material, designed to operate in combination with a printing cylinder
KR20080019628A (ko) * 2005-08-10 2008-03-04 가부시키가이샤 씽크. 라보라토리 닥터 블레이드
EP2059392B1 (en) * 2006-08-29 2010-06-09 Daetwyler Swisstec Ag Doctor blade
CH699702A1 (de) * 2008-10-07 2010-04-15 Daetwyler Swisstec Ag Diamantbeschichtete Rakel.
DE102009029698A1 (de) * 2009-09-23 2011-03-24 Voith Patent Gmbh Klingenbeschichtung
JP5859459B2 (ja) 2010-01-20 2016-02-10 デートワイラー・スイステック・アーゲー ドクターブレード
US20150299514A1 (en) * 2014-04-16 2015-10-22 Varel International Ind., L.P. Industrial tools with thermoset coating

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EP0911157A1 (de) * 1997-10-24 1999-04-28 MDC Max Dätwyler Bleienbach AG Rakel zum Abrakeln Überflüssiger Druckfarbe von der Oberfläche einer Druckform
EP0911157B1 (de) 1997-10-24 2002-02-27 MDC Max Dätwyler Bleienbach AG Rakel zum Abrakeln überflüssiger Druckfarbe von der Oberfläche einer Druckform
WO2013133762A1 (en) * 2012-03-08 2013-09-12 Swedev Ab Electrolytically puls-plated doctor blade with a multiple layer coating

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Publication number Publication date
BR112018011159A2 (pt) 2018-11-21
CN108367565A (zh) 2018-08-03
HK1252795A1 (zh) 2019-06-06
EP3386753B1 (de) 2020-01-29
ES2784689T3 (es) 2020-09-29
CN108367565B (zh) 2020-11-03
US10953649B2 (en) 2021-03-23
EP3386753A1 (de) 2018-10-17
JP2019500250A (ja) 2019-01-10
BR112018011159B1 (pt) 2023-02-07
US20180319154A1 (en) 2018-11-08
CA3005691A1 (en) 2017-06-15
CA3005691C (en) 2023-12-05
MX2018006423A (es) 2018-08-01
WO2017097995A1 (de) 2017-06-15
PL3386753T3 (pl) 2020-06-29

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