EP0286020A2 - Method of joining the cut-up edges of photopolymerised flexographic formes - Google Patents

Method of joining the cut-up edges of photopolymerised flexographic formes Download PDF

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Publication number
EP0286020A2
EP0286020A2 EP88105252A EP88105252A EP0286020A2 EP 0286020 A2 EP0286020 A2 EP 0286020A2 EP 88105252 A EP88105252 A EP 88105252A EP 88105252 A EP88105252 A EP 88105252A EP 0286020 A2 EP0286020 A2 EP 0286020A2
Authority
EP
European Patent Office
Prior art keywords
printing
edges
elongation
break
cylinders
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.)
Granted
Application number
EP88105252A
Other languages
German (de)
French (fr)
Other versions
EP0286020A3 (en
EP0286020B1 (en
Inventor
Heinz-Ulrich Dr. Werther
Hartwig Pieper
Willi Schabinger
Klaus Kessler
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.)
BASF SE
Original Assignee
BASF SE
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 BASF SE filed Critical BASF SE
Priority to AT88105252T priority Critical patent/ATE65743T1/en
Publication of EP0286020A2 publication Critical patent/EP0286020A2/en
Publication of EP0286020A3 publication Critical patent/EP0286020A3/en
Application granted granted Critical
Publication of EP0286020B1 publication Critical patent/EP0286020B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F27/00—Devices for attaching printing elements or formes to supports
    • B41F27/12—Devices for attaching printing elements or formes to supports for attaching flexible printing formes
    • B41F27/1262—Devices for attaching printing elements or formes to supports for attaching flexible printing formes without tensioning means
    • B41F27/1275—Devices for attaching printing elements or formes to supports for attaching flexible printing formes without tensioning means by means of adhesives, staples
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41D—APPARATUS FOR THE MECHANICAL REPRODUCTION OF PRINTING SURFACES FOR STEREOTYPE PRINTING; SHAPING ELASTIC OR DEFORMABLE MATERIAL TO FORM PRINTING SURFACES
    • B41D5/00—Working, treating, or handling stereotype plates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F27/00—Devices for attaching printing elements or formes to supports
    • B41F27/12—Devices for attaching printing elements or formes to supports for attaching flexible printing formes
    • B41F27/1293—Devices for filling up the cylinder gap; Devices for removing the filler
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N6/00—Mounting boards; Sleeves Make-ready devices, e.g. underlays, overlays; Attaching by chemical means, e.g. vulcanising
    • B41N6/02—Chemical means for fastening printing formes on mounting boards
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/02—Engraving; Heads therefor
    • B41C1/04—Engraving; Heads therefor using heads controlled by an electric information signal
    • B41C1/05—Heat-generating engraving heads, e.g. laser beam, electron beam
    • 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
    • Y10T156/00—Adhesive bonding and miscellaneous chemical manufacture
    • Y10T156/10—Methods of surface bonding and/or assembly therefor
    • Y10T156/1052—Methods of surface bonding and/or assembly therefor with cutting, punching, tearing or severing
    • Y10T156/1062—Prior to assembly
    • Y10T156/1066—Cutting to shape joining edge surfaces only

Definitions

  • a disadvantage of the known method is that the resulting gap closure compound is very firmly bonded to the material of the flexographic printing plate, so that it is not possible to separate the edges and remove the gap closure compound without damaging the printing plates.
  • the gap sealing compound as such has a very high elongation at break, so that after it has been produced it can only be smoothed by machine grinding, its thickness adapted to the printing forms and / or removed from the surface of the printing forms running along the connected edges, which can be removed by
  • a very particular disadvantage is when the edge connections cut through solid printing areas of the printing forms. Because mechanical sanding creates grinding marks in the surface of the printing forms, which have a different surface roughness and different ink transfer properties than the non-sanded areas and which are therefore already visible in the printed product at the start of the printing process. Because of its high elongation at break, the gap sealing compound can only be cut up, after which the remnants adhere very firmly to the printing form material. Or it can only be torn apart with great force, whereby the Printing forms are permanently damaged and are no longer reusable.
  • the flexing processes during printing can lead to a deformation of the precisely fitting edges of the carrier foils, which may be severely damaged under certain circumstances, on these flexographic printing plates which are fixed and connected to the edges on printing cylinders.
  • the object of the invention was to improve the known method for connecting the cut edges of photopolymerized flexographic printing plates, which have relief layers and dimensionally stable carrier films, on a printing cylinder in such a way that the disadvantages described above no longer occur.
  • all photopolymerizable mixtures are suitable for filling the gap between the edges to be joined in process step (a), provided that they are liquid and can be photopolymerized by UV radiation to give rubber-elastic gap sealing compounds.
  • the suitable mixtures contain binders, photopolymerizable monomers compatible with them and initiators of photopolymerization.
  • they can contain customary and known inhibitors of thermally initiated polymerization, antioxidants, antiozonants, plasticizers, fluxes, tackifiers, solvents and / or fillers.
  • photopolymerizable mixtures which are particularly suitable according to the invention are the solvent-free mixtures known from GB-A-2 160 882.
  • flexographic printing plates can be used as photopolymerized flexographic printing plates in the process according to the invention, which have relief layers and dimensionally stable carrier foils or consist of these and which are known to be obtained by imagewise exposure of printing plates which can be crosslinked by photopolymerization and washing out the unexposed and therefore uncrosslinked areas.
  • Printing plates suitable for this usually contain a photopolymerizable, relief-forming layer on a dimensionally stable carrier film.
  • the flexographic printing forms obtainable in this way have relief layer thicknesses of 0.7 to 10 mm, preferably 3 to 7 mm and a relief depth of 0.5 to 5 mm.
  • the width of the gap between the edges to be joined should generally not exceed 2 mm and not less than 0.1 mm. Gap widths between 0.5 and 1.5 mm are advantageous according to the invention.
  • the printing cylinders customary and known in flexographic printing are used.
  • the commercially available UV light sources such as the superactinic fluorescent tubes are suitable for exposing the photopolymerizable mixtures in process step (b).
  • Plates or foils made of suitable plastics such as polycarbonate, polypropylene, polyethylene or polyethylene terephthalate, which are pressed onto the gap filled with a photopolymerizable mixture, can be used as firmly attached, translucent covers.
  • the plates have approximately the same curvature as the surface of the impression cylinder.
  • the additional use of shrink films or plastic stockings is an advantage when connecting edges on a pressure cylinder.
  • the printing forms are fixed on dressing cylinders with the aid of customary and known adhesive films 1 before the liquid photopolymerizable mixture is filled in (method step (a)).
  • the adhesive films 1 have the same area as the printing forms.
  • the dressing cylinders or assembly cylinders to be used in the method according to the invention are part of a known, commercially available one Assembly equipment for the preparation of flexographic printing plates for multi-color printing.
  • the printing forms fixed on the dressing cylinders are cut to fit the printing cylinders, after which they are detached from the dressing cylinders and from the adhesive films 1. Thereafter, the precisely tailored printing forms are fixed on the printing cylinders by means of customary and known double-sided adhesive films 2.
  • the adhesive films 2 to be used in the method according to the invention are of the same area as the printing forms. However, they have 1.6 to 2.6 times, in particular 1.8 to 2.2 times, the thickness of the adhesive film 1.
  • dressing cylinders in the method according to the invention which have at least one notch running parallel to the axis and at least one notch running in the perpendicular direction.
  • the printing forms are fixed on these dressing cylinders in such a way that the notches come to rest under the interfaces.
  • edges of the printing forms and the adhesive films are then cut exactly along these notches, the cutting devices used for this being guided in these notches.
  • the usual and known cutting devices can be used here. It is particularly advantageous, however, to use 100 to 150 ° C., in particular 110 ° C. to 130 ° C., hot knives with a trapezoidal cutting edge in the method according to the invention, which can be moved parallel to the axis of the dressing cylinder and at an angle of 0 ° and 90 ° the cylinder axes are fixable.
  • the usual and well-known carpet cutters come into consideration as knives with a trapezoidal cutting edge. These can be heated using soldering irons to which they are attached.
  • the knee joints themselves can be fixed in two positions so that the knives are at an angle of 0 ° or 90 ° to the cylinder axes.
  • the dressing cylinders are fixed in the desired positions with the printing forms lying on them, and the knives are moved.
  • the knives are fixed in the desired position and the dressing cylinder is rotated.
  • the photopolymerizable mixture serving as the subsequent gap sealing compound is not completely polymerized in process step (b), but only partially.
  • the degree of photopolymerization or crosslinking may neither be chosen too high nor too low, because otherwise the particular advantages of the process according to the invention are lost.
  • the photopolymerizable mixture may therefore only be partially polymerized out until the conditions for the elongation at break in the combination of solid gap sealing compound and printing form material are the condition R S ⁇ R S / F «R F is fulfilled.
  • R S means the elongation at break of the solid gap closure compound. Depending on the photopolymerizable mixture used, it is 2 to 3 kp / 2 cm.
  • R S / F denotes the corresponding elongation at break in the interface between the gap sealing compound and the printing form material. Depending on the materials used, it is 1 to 2 kp / 2 cm.
  • R F denotes the elongation at break of the flexographic printing material. Depending on the material used, it is 6 kp / 2 cm or above 6 kp / 2 cm.
  • the elongation at break values can be easily determined using an Instron on 2 cm wide samples at a pull-off angle of 90 °.
  • the degree of photopolymerization or photocrosslinking can be set very easily via the exposure time. With given mixtures and flexographic printing plates, the optimal degree of polymerization or crosslinking, at which the condition according to the invention is fulfilled, can easily be determined on the basis of simple preliminary tests.
  • the liquid photopolymerizable mixture can be filled into the gap between two edges to be connected, for example by means of a high-pressure injection gun or by means of a cartridge with a curved outlet nozzle, from which the mixture is pressed out using a screw thread. If a high-pressure injection gun is used here, it is advantageous to cover the gap; when using a cartridge with an outlet nozzle, this is generally passed through the uncovered gap.
  • the gap fillings are advantageously covered with polyethylene terephthalate films, after which the printing cylinders together with the printing plates and polyethylene terephthalate films lying on them are bandaged in the usual manner with the known plastic stockings.
  • the polyethylene terephthalate films are pressed firmly onto the gap fillings, as a result of which some of these gap fillings can, under certain circumstances, be pressed again onto the surface of the printing forms that runs along the edges to be joined.
  • the solid gap sealing compounds After exposure of the gap fillings from the liquid photopolymerizable mixture in the procedure according to the invention, the solid gap sealing compounds are obtained, the elongation at break of which fulfills the critical condition as claimed.
  • These gap sealing compounds can be slightly curved. They can also have an uneven surface. They can also be thicker than the edge areas of the printing forms.
  • parts of the gap closure compound can along the connected Edges of the printing form are located. It may therefore be necessary to smooth these gap sealing compounds and / or to adapt their thickness to the printing forms and / or to remove the parts of the gap sealing compound which are located on the surface of the printing forms running along the connected edges.
  • the generally known mechanical methods such as grinding, cutting or sandblasting can be used for this.
  • the method according to the invention for connecting the cut edges of photopolymerized flexographic printing plates, which have relief layers and dimensionally stable carrier films, on a printing cylinder has particularly unexpected technical effects.
  • gaps are produced between the edges of printing forms to be connected, which are guided so narrowly and precisely that they do not make themselves noticeably noticeable even if they cut through printing solid areas of the printing forms.
  • edges of the dimensionally stable carrier foils of the printing forms no longer abut one another in the gaps and can therefore no longer cause any disadvantageous effects.
  • the partially polymerized gap closure compounds located in these columns and produced in the procedure according to the invention are easy to smooth and / or their thickness can be adapted to the printing forms.
  • parts of the gap sealing compounds can be removed from the surface of the printing plates running along the connected edges in a simple manner, without the surface being damaged or their surface roughness and their ink transfer properties being adversely changed.
  • the gap sealing compounds connect the edges seamlessly and are permanently sealed under printing conditions and resistant to the printing ink solvents. They are also not deformed or damaged by the flexing forces that occur during printing, so that - even after very long print runs - the masses are not raised or even detached. The columns are therefore hardly visible in the printed image.
  • the gap sealing compounds allow problem-free, clean re-opening of the Edges if the flexographic printing plate is to be removed from the printing cylinders and stored separately. The separation takes place above all at the interface between gap sealing compound and flexographic printing material; however, it can also occur to a minor extent in the gap closure material itself.
  • the remainder of the gap closure material which may still adhere to the edges, can be rubbed off or scraped off without any problem, without the printing plates being damaged.
  • the flexographic printing plates can be fixed again on the printing cylinders for reuse, after which their edges can be connected anew in the manner according to the invention. The method thus enables a somewhat reversible edge connection.
  • the flexographic printing forms connected to the edges by the process according to the invention have better printing behavior than those which have been connected by conventional processes.
  • ®Nyloflex FA flexographic printing plate from BASF Aktiengesellschaft with the dimensions 40 cm ⁇ 61 cm ⁇ 2.84 mm
  • the photopolymerized flexographic printing plate obtained in the known manner and having a thickness of 2.84 mm and a relief depth of 1.2 mm was cut to the dimensions 40 cm ⁇ 60 cm using a 0.1 mm thick, 40 cm ⁇ 61 cm , double-sided adhesive film 1 on the dressing cylinder of a commercially available assembly device (Bieffebi assembly device) so fixed that an axially parallel notch milled into the dressing cylinder came to lie exactly below the later interface in the flexographic printing plate. This interface was located in a solid printing area of the printing form.
  • the knife with which the cut was made consisted of the trapezoidal cutting edge of a commercially available carpet cutter, which was clamped in a soldering iron. This in turn was connected via a knee joint to a linkage attached below the front of the dressing cylinder and running axially parallel to it.
  • the knife edge was heated to 110 ° C by bending the knee joint into the notch of the Dressing cylinder inserted and fixed at an angle of 0 ° to the cylinder axis. After that, the dressing cylinder was locked.
  • the entire arrangement of knife, soldering iron and knee joint was then shifted along the rod parallel to the axis, the flexographic printing plate and the adhesive film 1 being cut very cleanly at the desired location.
  • the cut flexographic printing plate was then detached from the adhesive sheet 1 and applied to a printing cylinder (circumference: 40 cm) using a 0.2 mm thick, double-sided adhesive sheet 2 measuring 40 cm ⁇ 60 cm so that the 60 cm long side of the printing plate came to lie parallel to the cylinder axis.
  • a gap of 1.2 mm between the longitudinal edges of the printing form on the printing cylinder which gap had to be filled with gap sealing compound.
  • the surface of the flexographic printing plate was covered with adhesive strips along the edges to be joined.
  • This mixture was poured into a cartridge and pressed into the gap via a screw thread through a 0.8 mm wide, slightly curved outlet nozzle, the outlet nozzle being guided along the gap. This resulted in a filling with a slight curvature, which protruded above the level of the printing form surface. In part, the filling overflowed onto the surface of the flexographic printing plate covered with adhesive strips. These parts were removed from the flexographic printing plate surface together with the adhesive strips.
  • the gap filling was then covered with a polyethylene terephthalate film and the entire flexographic printing cylinder was wrapped with a polyethylene stocking running along the cylinder axis.
  • the mixture was then exposed in the gap in a tube exposer for 15 minutes. After this exposure time, which had been determined on the basis of preliminary tests, the mixture was polymerized to such an extent that the elongation at break R S (1.5 kg / 2 cm) and the elongation at break RS / F (2 kg / 2 cm) together with the elongation at break R F (6.5 kp / 2 cm) met the condition according to the invention.
  • the elongations at break were measured in a known manner using an Instron on 2 cm wide samples at a take-off angle of 90 °.
  • the gap sealing compound was smoothed by rubbing with a soft leather cloth or a plastic scraper, the thickness of the flexographic printing plate was adapted and removed from the surface of the flexographic printing plate running along the connected edges. Neither the printing form nor the gap sealing compound was damaged in any way.
  • Plastic sheets were printed with the usual alcohol-soluble flexographic printing ink using the finished flexographic printing cylinder in a conventional flexographic printing unit. Even after a run of 4.104 copies, the image reproduction was of excellent quality. The gap closure was hardly visible in the printed image. At the end of the printing process, the gap sealing compound showed no deformation, cracks or detachments. However, the gap sealing compound could very easily be removed from the gap by hand or with the aid of a plastic spatula, without the flexographic printing plate being damaged.
  • the flexographic printing plate was detached from the printing cylinder and stored separately. For reuse, it was fixed again with an adhesive film 2 on the printing cylinder and the gap between its edges was closed again in the manner described above.
  • the portions of the gap sealing compound that exceeded the level of the flexographic printing plate had to be cut away with a sharp knife because of their high toughness and strength. After this, the gap sealing compound had to be smoothed with a grinder. Both the grinding and the cutting were difficult to carry out because of the high rubber elasticity of the mass; Damage to the flexographic printing form could not be avoided.
  • the gap sealing compound could only be cut with a sharp knife. Remains of the gap sealing compound remained firmly attached to the printing form material. When trying to cut, tear off or grind away these adherent parts, the edge areas of the flexographic printing plate were severely damaged. The flexographic printing plate was therefore no longer suitable for reuse.

Abstract

A method of joining the edges of flexographic printing plates on printing cylinders, which includes the following steps: (i) fixing the printing plates to make-ready cylinders by means of a first double-sided self-adhesive film having the same area as the printing plate, (ii) cutting the printing plates to size so that they fit the printing cylinders, (iii) removing the cut printing plates from the make-ready cylinders and from the first self-adhesive films, (iv) fixing the cut printing plates by means of a second double-sided self-adhesive film, which has the same area as the printing plates and from 1.6 to 2.6 times the thickness of the first self-adhesive films, so that defined gaps result between the edges of the fixed printing plates, (v) filling the gaps between the edges to be joined, with a liquid photopolymerizable mixture of binders, photopolymerizable monomers and photopolymer, ization initiators and (vi) partially polymerizing the mixture under a transparent film cover by exposure to UV light until the elongation at break in the composite consisting of the solid gap closing compound and the printing plate material fulfils the condition RS<RS/F<<RF where RS is the elongation at break of the partially polymerized gap closing compound, RS/F is the elongation at break in the interface between the gap closing compound and the printing plate material and RF is the elongation at break of the printing plate material.

Description

Die Erfindung betrifft ein neues, verbessertes Verfahren zum Verbinden der zugeschnittenen Kanten photopolymerisierter Flexodruckformen, welche Reliefschichten und dimensionsstabile Trägerfolien aufweisen, auf einem Druckzylinder durch

  • a) Ausfüllen des Spaltes zwischen den zu verbindenden Kanten mit einem flüssigen photopolymerisierbaren Gemisch aus Bindemitteln, hiermit verträglichen photopolymerisierbaren Monomeren und Initiatoren der Photopolymerisation
    und
  • b) Auspolymerisieren des Gemisches unter einer fest aufliegenden, lichtdurchlässigen Abdeckung durch Bestrahlen mit UV-Licht.
The invention relates to a new, improved method for connecting the cut edges of photopolymerized flexographic printing plates, which have relief layers and dimensionally stable carrier films, on a printing cylinder
  • a) Filling the gap between the edges to be connected with a liquid photopolymerizable mixture of binders, photopolymerizable monomers compatible therewith and initiators of the photopolymerization
    and
  • b) Polymerization of the mixture under a fixed, translucent cover by irradiation with UV light.

Ein solches Verfahren ist, sieht man von der erfindungsgemäßen Verbesserung ab, aus der GB-A-2 160 882 bekannt.Apart from the improvement according to the invention, such a method is known from GB-A-2 160 882.

Nachteilig für das bekannte Verfahren ist es, daß die resultierende Spaltverschlußmasse sehr fest mit dem Material der Flexodruckform verbunden ist, so daß ein Wiederauftrennen der Kanten und ein Entfernen der Spaltverschlußmasse ohne Beschädigung der Druckformen nicht möglich ist.A disadvantage of the known method is that the resulting gap closure compound is very firmly bonded to the material of the flexographic printing plate, so that it is not possible to separate the edges and remove the gap closure compound without damaging the printing plates.

Überdies weist auch die Spaltverschlußmasse als solche eine sehr hohe Reißdehnung auf, so daß sie nach ihrer Herstellung nur durch maschinelles Abschleifen geglättet, in ihrer Dicke den Druckformen angepaßt und/oder von der längs der verbundenen Kanten verlaufenden Oberfläche der Druckformen entfernt werden kann, was von ganz besonderem Nachteil ist, wenn die Kantenverbindungen druckende Volltonflächen der Druckformen durchschneiden. Denn durch das maschinelle Abschleifen entstehen in der Oberfläche der Druckformen Schleifspuren, welche eine andere Oberflächen­rauhigkeit und andere Farbübertragungseigenschaften aufweisen als die nicht geschliffenen Bereiche und welche daher bereits zu Beginn des Druckvorgangs im Druckerzeugnis sichtbar werden. Wegen ihrer hohen Reißdehnung kann die Spaltverschlußmasse auch nur zerschnitten werden, wonach die Reste sehr fest an dem Druckformmaterial haften bleiben. Oder sie kann nur mit großer Kraft auseinandergerissen werden, wobei die Druckformen nachhaltig beschädigt werden und nicht mehr wiederverwendbar sind.In addition, the gap sealing compound as such has a very high elongation at break, so that after it has been produced it can only be smoothed by machine grinding, its thickness adapted to the printing forms and / or removed from the surface of the printing forms running along the connected edges, which can be removed by A very particular disadvantage is when the edge connections cut through solid printing areas of the printing forms. Because mechanical sanding creates grinding marks in the surface of the printing forms, which have a different surface roughness and different ink transfer properties than the non-sanded areas and which are therefore already visible in the printed product at the start of the printing process. Because of its high elongation at break, the gap sealing compound can only be cut up, after which the remnants adhere very firmly to the printing form material. Or it can only be torn apart with great force, whereby the Printing forms are permanently damaged and are no longer reusable.

Es ist daher nicht möglich, eine auf einem Druckzylinder fixierte, kantenverbundene Flexodruckform in einfacher Weise vom Druckzylinder abzutrennen, separat zu lagern und zur erneuten Verwendung wieder auf den selben oder auf einen anderen Druckzylinder aufzubringen. Weil aber Flexodruckformen üblicherweise mehrmals zum Drucken verwendet werden, bedeutet dies für die betriebliche Praxis, entweder für jede Druckform einen neuen Zylinder anzuschaffen oder im Laufe der Zeit mehrere Druckformen ein und desselben Motivs herzustellen, was sowohl wirtschaft­lich als auch technisch völlig unbefriedigend ist.It is therefore not possible to simply separate an edge-connected flexographic printing plate fixed on a printing cylinder from the printing cylinder, to store it separately and to re-use it on the same or on a different printing cylinder for reuse. However, because flexographic printing plates are usually used several times for printing, this means for business practice either to purchase a new cylinder for each printing plate or to produce several printing plates of the same motif over time, which is both economically and technically completely unsatisfactory.

Darüber hinaus können die Walkvorgänge beim Drucken bei diesen in bekannter Weise auf Druckzylindern fixierten und kantenverbundenen Flexodruckformen zu einer Deformation der paßgenau aneinanderstoßenden Kanten der Trägerfolien führen, was die Spaltverschlußmasse unter Umständen stark schädigt.In addition, the flexing processes during printing can lead to a deformation of the precisely fitting edges of the carrier foils, which may be severely damaged under certain circumstances, on these flexographic printing plates which are fixed and connected to the edges on printing cylinders.

Aufgabe der Erfindung war es, das bekannte Verfahren zum Verbinden der zugeschnittenen Kanten photopolymerisierter Flexodruckformen, welche Reliefschichten und dimensionsstabile Trägerfolien aufweisen, auf einem Druckzylinder so zu verbessern, daß die vorstehend geschilderten Nachteile nicht mehr auftreten.The object of the invention was to improve the known method for connecting the cut edges of photopolymerized flexographic printing plates, which have relief layers and dimensionally stable carrier films, on a printing cylinder in such a way that the disadvantages described above no longer occur.

Demgemäß wurde ein neues Verfahren zum Verbinden der zugeschnittenen Kanten photopolymerisierter Flexodruckformen, welche Reliefschichten und dimensionsstabile Trägerfolien aufweisen, auf einem Druckzylinder durch

  • a) Ausfüllen des Spaltes zwischen den zu verbindenden Kanten mit einem flüssigen photopolymerisierbaren Gemisch aus Bindemitteln, hiermit verträglichen photopolymerisierbaren Monomeren und Initiatoren der Photopolymerisation
und
  • b) Auspolymerisieren des Gemisches unter einer fest aufliegenden, lichtdurchlässigen Abdeckung durch Bestrahlen mit UV-Licht,
gefunden, welches dadurch gekennzeichnet ist, daß man
  • a₁) die Druckformen vor dem Verfahrensschritt (a) mittels doppelseitiger Klebfolien 1 von gleicher Fläche wie die Druckformen auf Zurichtezylindern fixiert und auf die Druckzylinder passend zuschneidet, wonach man sie von den Zurichtezylindern und von den Klebfolien 1 ablöst, um sie anschließend mittels doppelseitiger Klebfolien 2 von gleicher Fläche wie die Druckformen und der 1,6- bis 2,6-fachen Dicke der Klebfolien 1 auf den Druckzylindern zu befestigen,
und daß man
  • b₁) bei dem Verfahrensschritt (b) das Gemisch nur so lange partiell auspolymerisiert, bis für die Werte der Reißdehnung in dem Verbund aus fester Spaltverschlußmasse und Druckformmaterial die Bedingung
          RS < RS/F « RF erfüllt ist, worin
    RS      die Reißdehnung der partiell auspolymerisierten Spaltverschluß­
    masse,
    RS/F      die Reißdehnung in der Grenzfläche zwischen der Spaltverschluß­masse und dem Druckformmaterial und
    RF      die Reißdehnung des Druckformmaterials
    bedeutet.
Accordingly, a new method for connecting the cut edges of photopolymerized flexographic printing plates, which have relief layers and dimensionally stable carrier films, was carried out on a printing cylinder
  • a) Filling the gap between the edges to be connected with a liquid photopolymerizable mixture of binders, photopolymerizable monomers compatible therewith and initiators of the photopolymerization
and
  • b) polymerizing out the mixture under a fixed, transparent cover by irradiation with UV light,
found, which is characterized in that one
  • a₁) the printing forms before process step (a) by means of double-sided adhesive films 1 of the same area as the printing forms fixed on dressing cylinders and fitting on the printing cylinders cut to size, after which they are detached from the dressing cylinders and from the adhesive films 1, in order to subsequently fix them on the printing cylinders by means of double-sided adhesive films 2 of the same area as the printing plates and 1.6 to 2.6 times the thickness of the adhesive films 1,
and that one
  • b₁) in process step (b), the mixture is only partially polymerized until the values for the elongation at break in the composite of solid gap sealing compound and printing form material are the condition
    R S <R S / F «R F is fulfilled, in which
    R S is the elongation at break of the partially polymerized gap closure
    Dimensions,
    R S / F is the elongation at break in the interface between the gap sealing compound and the printing form material and
    R F is the elongation at break of the printing plate material
    means.

Für das Ausfüllen des Spaltes zwischen den zu verbindenden Kanten im Verfahrensschritt (a) sind an und für sich alle photopolymerisierbaren Gemische geeignet, sofern sie flüssig sind und durch UV-Bestrahlung zu gummielastischen Spaltverschlußmassen photopolymerisiert werden können.In principle, all photopolymerizable mixtures are suitable for filling the gap between the edges to be joined in process step (a), provided that they are liquid and can be photopolymerized by UV radiation to give rubber-elastic gap sealing compounds.

Im allgemeinen enthalten die geeigneten Gemische Bindemittel, hiermit verträgliche photopolymerisierbare Monomere und Initiatoren der Photopolymerisation. Darüber hinaus können sie übliche und bekannte Inhibitoren der thermisch initiierten Polymerisation, Antioxidantien, Ozonschutzmittel, Weichmacher, Flußmittel, klebrigmachende Stoffe, Lösungsmittel und/oder Füllstoffe enthalten.In general, the suitable mixtures contain binders, photopolymerizable monomers compatible with them and initiators of photopolymerization. In addition, they can contain customary and known inhibitors of thermally initiated polymerization, antioxidants, antiozonants, plasticizers, fluxes, tackifiers, solvents and / or fillers.

Beispiele für erfindungsgemäß besonders gut geeignete photopolymerisier­bare Gemische sind die aus der GB-A-2 160 882 bekannten lösungsmittel­freien Gemische.Examples of photopolymerizable mixtures which are particularly suitable according to the invention are the solvent-free mixtures known from GB-A-2 160 882.

Als photopolymerisierte Flexodruckformen können bei dem erfindungsgemäßen Verfahren die üblichen bekannten Flexodruckformen verwendet werden, welche Reliefschichten und dimensionsstabile Trägerfolien aufweisen oder aus diesen bestehen und welche man bekanntermaßen durch bildmäßiges Belichten von durch Photopolymerisation vernetzbaren Druckplatten und Auswaschen der unbelichteten und daher unvernetzten Bereiche erhält. Hierfür geeignete Druckplatten enthalten üblicherweise eine photopolymerisierbare, reliefbildende Schicht auf einer dimensionsstabilen Trägerfolie.The usual known flexographic printing plates can be used as photopolymerized flexographic printing plates in the process according to the invention, which have relief layers and dimensionally stable carrier foils or consist of these and which are known to be obtained by imagewise exposure of printing plates which can be crosslinked by photopolymerization and washing out the unexposed and therefore uncrosslinked areas. Printing plates suitable for this usually contain a photopolymerizable, relief-forming layer on a dimensionally stable carrier film.

Im allgemeinen weisen die so erhältlichen Flexodruckformen Reliefschicht­dicken von 0,7 bis 10 mm, vorzugsweise 3 bis 7 mm und eine Relieftiefe von 0,5 bis 5 mm auf.In general, the flexographic printing forms obtainable in this way have relief layer thicknesses of 0.7 to 10 mm, preferably 3 to 7 mm and a relief depth of 0.5 to 5 mm.

Die Breite des Spaltes zwischen den zu verbindenden Kanten sollte im allgemeinen 2 mm nicht überschreiten und 0,1 mm nicht unterschreiten. Erfindungsgemäß von Vorteil sind Spaltbreiten zwischen 0,5 und 1,5 mm.The width of the gap between the edges to be joined should generally not exceed 2 mm and not less than 0.1 mm. Gap widths between 0.5 and 1.5 mm are advantageous according to the invention.

Bei dem erfindungsgemäßen Verfahren verwendet man die im Flexodruck üblichen und bekannten Druckzylinder.In the method according to the invention, the printing cylinders customary and known in flexographic printing are used.

Für das Belichten der photopolymerisierbaren Gemische im Verfahrens­schritt (b) sind die handelsüblichen UV-Lichtquellen wie die super­aktinischen Leuchtstoffröhren geeignet.The commercially available UV light sources such as the superactinic fluorescent tubes are suitable for exposing the photopolymerizable mixtures in process step (b).

Als fest aufliegende, lichtdurchlässige Abdeckungen können Platten oder Folien aus geeigneten Kunststoffen wie Polycarbonat, Polypropylen, Polyethylen oder Polyethylenterephthalat verwendet werden, welche auf den mit photopolymerisierbarem Gemisch gefüllten Spalt aufgepreßt werden. Dabei weisen die Platten in etwa die gleiche Krümmung wie die Druck­zylinderoberfläche auf. Die zusätzliche Verwendung von Schrumpffolien oder Kunststoffstrümpfen ist bei der Kantenverbindung auf einem Druckzylinder von Vorteil.Plates or foils made of suitable plastics, such as polycarbonate, polypropylene, polyethylene or polyethylene terephthalate, which are pressed onto the gap filled with a photopolymerizable mixture, can be used as firmly attached, translucent covers. The plates have approximately the same curvature as the surface of the impression cylinder. The additional use of shrink films or plastic stockings is an advantage when connecting edges on a pressure cylinder.

Nach dem erfindungsgemäßen Verfahren werden die Druckformen vor dem Einfüllen des flüssigen photopolymerisierbaren Gemisches (Verfahrens­schritt (a) mit Hilfe üblicher und bekannter Klebfolien 1 auf Zurichtezylindern fixiert.According to the method according to the invention, the printing forms are fixed on dressing cylinders with the aid of customary and known adhesive films 1 before the liquid photopolymerizable mixture is filled in (method step (a)).

Die Klebfolien 1 weisen die gleiche Fläche wie die Druckformen auf.The adhesive films 1 have the same area as the printing forms.

Die bei dem erfindungsgemäßen Verfahren zu verwendende Zurichtezylinder oder Montagezylinder sind Bestandteil an sich bekannter, handelsüblicher Montagegeräte für die Zurichtung von Flexodruckformen für den Mehr­farbendruck.The dressing cylinders or assembly cylinders to be used in the method according to the invention are part of a known, commercially available one Assembly equipment for the preparation of flexographic printing plates for multi-color printing.

Die auf den Zurichtezylindern fixierten Druckformen werden auf die Druckzylinder passend zugeschnitten, wonach man sie von den Zurichte­zylindern und von den Klebfolien 1 ablöst. Hiernach werden die passgenau zugeschnittenen Druckformen mittels üblicher und bekannter, doppelseitiger Klebfolien 2 auf den Druckzylindern fixiert.The printing forms fixed on the dressing cylinders are cut to fit the printing cylinders, after which they are detached from the dressing cylinders and from the adhesive films 1. Thereafter, the precisely tailored printing forms are fixed on the printing cylinders by means of customary and known double-sided adhesive films 2.

Die bei dem erfindungsgemäßen Verfahren zu verwendenden Klebfolien 2 sind von gleicher Fläche wie die Druckformen. Sie weisen aber die 1,6- bis 2,6-fache, insbesondere die 1,8- bis 2,2-fache Dicke der Klebfolie 1 auf.The adhesive films 2 to be used in the method according to the invention are of the same area as the printing forms. However, they have 1.6 to 2.6 times, in particular 1.8 to 2.2 times, the thickness of the adhesive film 1.

Es ist besonders vorteilhaft, bei dem erfindungsgemäßen Verfahren Zu­richtezylidner zu verwenden, welche mindestens eine achsparallel verlau­fende Kerbe und mindestens eine in senkrechter Richtung hierzu verlaufende Kerbe aufweisen. Auf diesen Zurichtezylindern werden die Druckformen so fixiert, daß die Kerben unter den Schnittstellen zu liegen kommen.It is particularly advantageous to use dressing cylinders in the method according to the invention which have at least one notch running parallel to the axis and at least one notch running in the perpendicular direction. The printing forms are fixed on these dressing cylinders in such a way that the notches come to rest under the interfaces.

Der genaue Zuschnitt der Kanten der Druckformen und der Klebfolien erfolgt dann längs dieser Kerben, wobei die hierfür verwendeten Schneidegeräte in diesen Kerben geführt werden.The edges of the printing forms and the adhesive films are then cut exactly along these notches, the cutting devices used for this being guided in these notches.

Es können hierbei die üblichen und bekannten Schneidegeräte verwendet werden. Es ist indes besonders vorteilhaft, bei dem erfindungsgemäßen Verfahren 100 bis 150°C, insbesondere 110°C bis 130°C heiße Messer mit trapezförmiger Schneide anzuwenden, welche parallel zur Achse der Zurichtezylinder verschiebbar und in einem Winkel von 0° und von 90° zu den Zylinderachsen fixierbar sind.The usual and known cutting devices can be used here. It is particularly advantageous, however, to use 100 to 150 ° C., in particular 110 ° C. to 130 ° C., hot knives with a trapezoidal cutting edge in the method according to the invention, which can be moved parallel to the axis of the dressing cylinder and at an angle of 0 ° and 90 ° the cylinder axes are fixable.

Dabei kommen als Messer mit trapezförmiger Schneide die üblichen und bekannten Teppichschneider in Betracht. Diese können mit Hilfe von Lötkolben, an welchen sie befestigt sind, beheizt werden.The usual and well-known carpet cutters come into consideration as knives with a trapezoidal cutting edge. These can be heated using soldering irons to which they are attached.

Diese Anordnungen aus Schneide und Lötkolben können über Kniegelenke mit Gestängen verbunden werden, welche unterhalb der Vorderseite der Zurichte­zylinder angebracht sind und parallel zu deren Achse verlaufen, wobei die Anordnungen aus Schneide, Lötkolben und Kniegelenk längs dieser Gestänge achsparallel verschoben werden können.These arrangements of cutting edge and soldering iron can be connected via knee joints to rods which are attached below the front of the dressing cylinder and run parallel to their axis, the arrangements of cutting edge, soldering iron and knee joint being able to be displaced axially parallel along these rods.

Die Kniegelenke selber können in zwei Stellungen so fixiert werden, daß die Messer fest in einem Winkel von 0° oder von 90° zu den Zylinderachsen stehen.The knee joints themselves can be fixed in two positions so that the knives are at an angle of 0 ° or 90 ° to the cylinder axes.

Für den Zuschnitt in achsparalleler Richtung werden die Zurichtezylinder mit den aufliegenden Druckformen in den gewünschten Stellungen fixiert, und es werden die Messer bewegt.For the cutting in the direction parallel to the axis, the dressing cylinders are fixed in the desired positions with the printing forms lying on them, and the knives are moved.

Für den Zuschnitt in senkrechter Richtung zur Achse der Zurichtezylinder werden die Messer in der gewünschten Stellung fixiert, und es werden die Zurichtezylinder gedreht.For the cutting in the direction perpendicular to the axis of the dressing cylinder, the knives are fixed in the desired position and the dressing cylinder is rotated.

Im Unterschied zu dem bekannten Verfahren wird bei dem erfindungsgemäßen Verfahren das als spätere Spaltverschlußmasse dienende photopolymerisier­bare Gemisch im Verfahrensschritt (b) nicht vollständig, sondern nur partiell auspolymerisiert. Dabei darf der Grad der Photopolymerisation oder -vernetzung weder zu hoch noch zu niedrig gewählt werden, weil ansonsten die besonderen Vorteile des erfindungsgemäßen Verfahrens verlorengehen. Das photopolymerisierbare Gemisch darf daher nur so lange partiell auspolymerisiert werden, bis für die Werte der Reißdehnung im Verbund aus fester Spaltverschlußmasse und Druckformmaterial die Bedingung
    RS < RS/F « RF erfüllt ist.In contrast to the known method, in the method according to the invention the photopolymerizable mixture serving as the subsequent gap sealing compound is not completely polymerized in process step (b), but only partially. The degree of photopolymerization or crosslinking may neither be chosen too high nor too low, because otherwise the particular advantages of the process according to the invention are lost. The photopolymerizable mixture may therefore only be partially polymerized out until the conditions for the elongation at break in the combination of solid gap sealing compound and printing form material are the condition
R S <R S / F «R F is fulfilled.

Dabei bedeutet RS die Reißdehnung der festen Spaltverschlußmasse. Je nach verwendetem photopolymerisierbarem Gemisch liegt sie bei 2 bis 3 kp/2 cm.R S means the elongation at break of the solid gap closure compound. Depending on the photopolymerizable mixture used, it is 2 to 3 kp / 2 cm.

RS/F bezeichnet die entsprechende Reißdehnung in der Grenzfläche zwischen der Spaltverschlußmasse und dem Druckformmaterial. Je nach den verwendeten Materialien liegt sie bei 1 bis 2 kp/2 cm.R S / F denotes the corresponding elongation at break in the interface between the gap sealing compound and the printing form material. Depending on the materials used, it is 1 to 2 kp / 2 cm.

RF bezeichnet die Reißdehnung des Flexodruckformmaterials. Je nach verwendetem Material liegt sie bei 6 kp/2 cm oder oberhalb 6 kp/2 cm.R F denotes the elongation at break of the flexographic printing material. Depending on the material used, it is 6 kp / 2 cm or above 6 kp / 2 cm.

Die Werte der Reißdehnung können in einfacher Weise mit Hilfe eines Instrons an 2 cm breiten Proben bei einem Abzugswinkel von 90° ermittelt werden.The elongation at break values can be easily determined using an Instron on 2 cm wide samples at a pull-off angle of 90 °.

Der Grad der Photopolymerisation oder der Photovernetzung kann sehr leicht über die Belichtungszeit eingestellt werden. Bei vorgegebenen Gemischen und Flexodruckformen läßt sich daher der optimale Polymerisations- oder Vernetzungsgrad, bei welchem die erfindungsgemäße Bedingung erfüllt ist, anhand einfacher Vorversuche leicht ermitteln.The degree of photopolymerization or photocrosslinking can be set very easily via the exposure time. With given mixtures and flexographic printing plates, the optimal degree of polymerization or crosslinking, at which the condition according to the invention is fulfilled, can easily be determined on the basis of simple preliminary tests.

Im Hinblick auf den Stand der Technik war es überraschend, daß die der Erfindung zugrundeliegende Aufgabe mit Hilfe dieser Verfahrensmaßnahme gelöst werden kann, ohne daß sich dabei die allgemein bekannten Nachteile unvollständig auspolymerisierter photopolymerisierbarer Gemische bemerkbar machen. So sind solche Gemische bekanntermaßen weniger gummielastisch, mechanisch instabiler und weniger resistent gegenüber Lösungsmittel­einwirkung als vollständig auspolymerisierte Gemische, so daß sie von vornherein als völlig ungeeignet erscheinen, einen mechanisch hochbelast­baren und auf Dauer dichten Spaltverschluß zwischen den Kanten von Flexodruckformen zu bilden.In view of the prior art, it was surprising that the object on which the invention is based was achieved with the aid of this process measure can be solved without the generally known disadvantages of incompletely polymerized photopolymerizable mixtures being noticed. Such mixtures are known to be less rubber-elastic, mechanically unstable and less resistant to the effects of solvents than fully polymerized mixtures, so that they appear from the outset to be completely unsuitable for forming a mechanically heavy-duty and permanently sealed gap seal between the edges of flexographic printing plates.

Im Verfahrensschritt (a) kann das Einfüllen des flüssigen photopoly­merisierbaren Gemisches in den Spalt zwischen zwei zu verbindenden Kanten beispielsweise mittels einer Hochdruckinjektionspistole oder mittels einer Kartusche mit einer gebogenen Auslaufdüse, aus welcher das Gemisch mit Hilfe eines Schraubgewindes herausgepreßt wird, erfolgen. Verwendet man hierbei eine Hochdruckinjektionspistole, so ist es von Vorteil, den Spalt zu bedecken, bei Verwendung einer Kartusche mit einer Auslaufdüse wird diese im allgemeinen durch den unbedeckten Spalt hindurchgeführt.In process step (a), the liquid photopolymerizable mixture can be filled into the gap between two edges to be connected, for example by means of a high-pressure injection gun or by means of a cartridge with a curved outlet nozzle, from which the mixture is pressed out using a screw thread. If a high-pressure injection gun is used here, it is advantageous to cover the gap; when using a cartridge with an outlet nozzle, this is generally passed through the uncovered gap.

Dabei resultieren im allgemeinen leicht gewölbte flüssige Spaltfüllungen, wobei die längs der zu verbindenden Kanten verlaufende Oberfläche der Druckformen von dem flüssigen Gemisch bedeckt sein kann. Es ist daher von besonderem Vorteil für das erfindungsgemäße Verfahren, diesen Teil der Oberfläche der Druckformen mit Klebstreifen abzudecken. Hierzu können übliche und bekannte Klebstreifen verwendet werden. Diese Klebstreifen werden dann nach dem Einfüllvorgang (Verfahrensschritt a) zusammen mit dem überstehenden, aus den Spalten übergeflossenen Gemisch entfernt.This generally results in slightly curved liquid gap fillings, and the surface of the printing formes running along the edges to be connected can be covered by the liquid mixture. It is therefore particularly advantageous for the method according to the invention to cover this part of the surface of the printing forms with adhesive strips. Conventional and known adhesive strips can be used for this. These adhesive strips are then removed after the filling process (process step a) together with the excess mixture which has overflowed from the gaps.

Vor der Belichtung in der erfindungsgemäßen Verfahrensweise werden die Spaltfüllungen vorteilhafterweise mit Polyethylenterephthalatfolien bedeckt, wonach man die Druckzylinder samt aufliegenden Druckformen und Polyethylenterephthalatfolien mit den bekannten Kunststoffstrümpfen in üblicher Weise bandagiert. Durch diese Bandagierung werden die Poly­ethylenterephthalatfolien fest auf die Spaltfüllungen gedrückt, wodurch ein Teil dieser Spaltfüllungen unter Umständen wieder auf die längs der zu verbindenden Kanten verlaufende Oberfläche der Druckformen gepreßt werden kann.Before exposure in the procedure according to the invention, the gap fillings are advantageously covered with polyethylene terephthalate films, after which the printing cylinders together with the printing plates and polyethylene terephthalate films lying on them are bandaged in the usual manner with the known plastic stockings. As a result of this bandaging, the polyethylene terephthalate films are pressed firmly onto the gap fillings, as a result of which some of these gap fillings can, under certain circumstances, be pressed again onto the surface of the printing forms that runs along the edges to be joined.

Nach der Belichtung der Spaltfüllungen aus dem flüssigen photopoly­merisierbaren Gemisch in der erfindungsgemäßen Verfahrensweise erhält man die festen Spaltverschlußmassen, deren Reißdehnung die anspruchsgemäße kritische Bedingung erfüllt. Diese Spaltverschlußmassen können leicht gewölbt sein. Sie können auch eine unebene Oberfläche aufweisen. Außerdem können sie dicker sein als die Kantenbereiche der Druckformen. Überdies können sich Teile der Spaltverschlußmasse auf der längs der verbundenen Kanten verlaufenden Oberfläche der Druckformen befinden. Es kann daher notwendig werden, diese Spaltverschlußmassen zu glätten und/oder in ihrer Dicke den Druckformen anzupassen und/oder die Teile der Spaltverschluß­masse, welche sich auf der längs der verbundenen Kanten verlaufenden Oberfläche der Druckformen befinden, zu entfernen. Hierfür können die allgemein bekannten maschinellen Methoden wie Schleifen, Schneiden oder Abstrahlen angewendet werden. Wegen der vorteilhaften Eigenschaften der in erfindungsgemäßer Verfahrensweise erhaltenen Spaltverschlußmassen genügt indes ein leichtes Abreiben oder Abschaben der betreffenden Teile der Spaltverschlußmassen. Dies kann unter Umständen sogar per Hand erfolgen. Dabei wird die Oberfläche der Druckformen weder geschädigt, noch in ihrer Oberflächenrauhigkeit und ihren Farbübertragungseigenschaften geändert.After exposure of the gap fillings from the liquid photopolymerizable mixture in the procedure according to the invention, the solid gap sealing compounds are obtained, the elongation at break of which fulfills the critical condition as claimed. These gap sealing compounds can be slightly curved. They can also have an uneven surface. They can also be thicker than the edge areas of the printing forms. In addition, parts of the gap closure compound can along the connected Edges of the printing form are located. It may therefore be necessary to smooth these gap sealing compounds and / or to adapt their thickness to the printing forms and / or to remove the parts of the gap sealing compound which are located on the surface of the printing forms running along the connected edges. The generally known mechanical methods such as grinding, cutting or sandblasting can be used for this. Because of the advantageous properties of the gap sealing compounds obtained in the procedure according to the invention, a slight rubbing or scraping off of the relevant parts of the gap sealing compounds is sufficient. Under certain circumstances, this can even be done by hand. The surface of the printing forms is neither damaged, nor is their surface roughness and ink transfer properties changed.

Das erfindungsgemäße Verfahren zum Verbinden der zugeschnittenen Kanten photopolymerisierter Flexodruckformen, welche Reliefschichten und dimensionsstabile Trägerfolien aufweisen, auf einem Druckzylinder hat besondere unerwartete technische Effekte zur Folge.The method according to the invention for connecting the cut edges of photopolymerized flexographic printing plates, which have relief layers and dimensionally stable carrier films, on a printing cylinder has particularly unexpected technical effects.

So werden einerseits mit Hilfe des erfindungsgemäßen Verfahrens Spalten zwischen zu verbindenden Kanten von Druckformen erzeugt, welche so schmal und exakt geführt sind, daß sie sich selbst dann nicht nachteilig bemerk­bar machen, wenn sie druckende Volltonflächen der Druckformen durch­schneiden.Thus, on the one hand, with the aid of the method according to the invention, gaps are produced between the edges of printing forms to be connected, which are guided so narrowly and precisely that they do not make themselves noticeably noticeable even if they cut through printing solid areas of the printing forms.

Andererseits stoßen die Kanten der dimensionsstabilen Trägerfolien der Druckformen in den Spalten nicht länger aneinander und können daher auch keine nachteiligen Effekte mehr hervorrufen.On the other hand, the edges of the dimensionally stable carrier foils of the printing forms no longer abut one another in the gaps and can therefore no longer cause any disadvantageous effects.

Die in diesen Spalten befindlichen, in erfindungsgemäßer Verfahrensweise erzeugten, partiell auspolymerisierten Spaltverschlußmassen sind leicht zu glätten und/oder in ihrer Dicke den Druckformen anzupassen. Überdies können Teile der Spaltverschlußmassen von der längs der verbundenen Kanten verlaufenden Oberfläche der Druckformen in einfacher Weise entfernt werden, ohne daß hierbei die Oberfläche geschädigt wird oder in ihrer Oberflächenrauhigkeit und ihren Farbübertragungseigenschaften nachteilig geändert wird.The partially polymerized gap closure compounds located in these columns and produced in the procedure according to the invention are easy to smooth and / or their thickness can be adapted to the printing forms. In addition, parts of the gap sealing compounds can be removed from the surface of the printing plates running along the connected edges in a simple manner, without the surface being damaged or their surface roughness and their ink transfer properties being adversely changed.

Die Spaltverschlußmassen verbinden die Kanten nahtlos und sind unter Druckbedingungen dauerhaft dicht und beständig gegenüber den Druckfarben­lösungsmitteln. Sie werden auch nicht durch die beim Drucken auftretenden Walkkräfte deformiert oder geschädigt, so daß es - selbst nach sehr hohen Druckauflagen - zu keinem Aufwerfen oder gar Ablösen der Massen kommt. Die Spalten werden daher im Druckbild kaum sichtbar. Überdies erlauben die Spaltverschlußmassen ein problemloses, sauberes Wiederauftrennen der Kanten, wenn die Flexodruckform von den Druckzylindern abgenommen und separat gelagert werden sollen. Die Trennung erfolgt dabei vor allem an der Grenzfläche zwischen Spaltverschlußmasse und Flexodruckformmaterial; sie kann indes auch in untergeordnetem Ausmaß im Spaltverschlußmaterial selbst geschehen. Nach der Trennung können die Reste des Spaltverschluß­materials, welche gegebenenfalls noch an den Kanten haften, völlig problemlos abgerieben oder abgeschabt werden, ohne daß es hierbei zu einer Schädigung der Druckformen kommt. Die Flexodruckformen können für die Wiederverwendung erneut auf den Druckzylindern fixiert werden, wonach ihre Kanten aufs neue in der erfindungsgemäßen Weise verbunden werden können. Das Verfahren ermöglicht somit eine in gewissem Umfange reversible Kantenverbindung. Darüber hinaus weisen die nach dem erfindungsgemäßen Verfahren kantenverbundenen Flexodruckformen ein besseres Druckverhalten auf als solche, welche man nach herkömmlichen Verfahren verbunden hat.The gap sealing compounds connect the edges seamlessly and are permanently sealed under printing conditions and resistant to the printing ink solvents. They are also not deformed or damaged by the flexing forces that occur during printing, so that - even after very long print runs - the masses are not raised or even detached. The columns are therefore hardly visible in the printed image. In addition, the gap sealing compounds allow problem-free, clean re-opening of the Edges if the flexographic printing plate is to be removed from the printing cylinders and stored separately. The separation takes place above all at the interface between gap sealing compound and flexographic printing material; however, it can also occur to a minor extent in the gap closure material itself. After the separation, the remainder of the gap closure material, which may still adhere to the edges, can be rubbed off or scraped off without any problem, without the printing plates being damaged. The flexographic printing plates can be fixed again on the printing cylinders for reuse, after which their edges can be connected anew in the manner according to the invention. The method thus enables a somewhat reversible edge connection. In addition, the flexographic printing forms connected to the edges by the process according to the invention have better printing behavior than those which have been connected by conventional processes.

Beispielexample Herstellung eines Flexodruckzylinders nach dem erfindungsgemäßen Verfahren; Herstellvorschrift:Production of a flexographic printing cylinder by the method according to the invention; Manufacturing specification:

Eine handelsübliche photopolymerisierbare Flexodruckplatte aus einer photopolymerisierbaren, reliefbildenden Schicht auf der Basis eines Butadien-Isopren-Styrol-Blockkautschuks und aus einer dimensionsstabilen Trägerfolie aus Polyethylenterephthalat (®Nyloflex FA-Flexodruckplatte der BASF Aktiengesellschaft mit den Abmessungen 40 cm × 61 cm × 2,84 mm) wurde wie üblich bildmäßig belichtet, entwickelt, ausgewaschen und nachbe­handelt.A commercially available photopolymerizable flexographic printing plate made of a photopolymerizable, relief-forming layer based on a butadiene-isoprene-styrene block rubber and a dimensionally stable carrier film made of polyethylene terephthalate (®Nyloflex FA flexographic printing plate from BASF Aktiengesellschaft with the dimensions 40 cm × 61 cm × 2.84 mm ) was exposed imagewise, developed, washed out and aftertreated as usual.

Die in der bekannten Weise erhaltene photopolymerisierte Flexodruckform einer Dicke von 2,84 mm und einer Relieftiefe von 1,2 mm wurde für den Zuschnitt auf die Maße 40 cm × 60 cm mit Hilfe einer 0,1 mm dicken, 40 cm × 61 cm großen, doppelseitigen Klebfolie 1 auf dem Zurichtezylinder eines handelsüblichen Montagegerätes (Bieffebi-Montagegerät) so fixiert, daß eine in den Zurichtezylinder eingefräste, achsparallele Kerbe genau unter der späteren Schnittstelle in der Flexodruckform zu liegen kam. Diese Schnittstelle befand sich in einer druckenden Volltonfläche der Druckform.The photopolymerized flexographic printing plate obtained in the known manner and having a thickness of 2.84 mm and a relief depth of 1.2 mm was cut to the dimensions 40 cm × 60 cm using a 0.1 mm thick, 40 cm × 61 cm , double-sided adhesive film 1 on the dressing cylinder of a commercially available assembly device (Bieffebi assembly device) so fixed that an axially parallel notch milled into the dressing cylinder came to lie exactly below the later interface in the flexographic printing plate. This interface was located in a solid printing area of the printing form.

Das Messer, mit welchem geschnitten wurde, bestand aus der trapezförmigen Schneide eines handelsüblichen Teppichschneiders, welche in einen Lötkolben eingespannt war. Dieser wiederum war über ein Kniegelenk mit einem unterhalb der Vorderseite des Zurichtezylinders angebrachten und achsparallel zu diesem verlaufenden Gestänge verbunden. Die Messerschneide wurde auf 110°C erhitzt, durch Beugen des Kniegelenks in die Kerbe des Zurichtezylinders eingeführt und in einem Winkel von 0° zur Zylinderachse fixiert. Hiernach wurde der Zurichtezylinder gesperrt. Danach wurde die gesamte Anordnung aus Messer, Lötkolben und Kniegelenk längs des Gestänges achsparallel verschoben, wobei die Flexodruckform und die Klebfolie 1 sehr sauber an der gewünschten Stelle durchtrennt wurden.The knife with which the cut was made consisted of the trapezoidal cutting edge of a commercially available carpet cutter, which was clamped in a soldering iron. This in turn was connected via a knee joint to a linkage attached below the front of the dressing cylinder and running axially parallel to it. The knife edge was heated to 110 ° C by bending the knee joint into the notch of the Dressing cylinder inserted and fixed at an angle of 0 ° to the cylinder axis. After that, the dressing cylinder was locked. The entire arrangement of knife, soldering iron and knee joint was then shifted along the rod parallel to the axis, the flexographic printing plate and the adhesive film 1 being cut very cleanly at the desired location.

Die zugeschnittene Flexodruckform wurde nun von der Klebfolie 1 abgelöst und mit Hilfe einer 0,2 mm dicken, doppelseitigen Klebfolie 2 der Abmessung 40 cm × 60 cm auf einen Druckzylinder (Umfang: 40 cm) so aufgebracht, daß die 60 cm lange Seite der Druckform parallel zur Zylinderachse zu liegen kam. Dadurch befand sich zwischen den Längskanten der Druckform auf dem Druckzylinder ein Spalt von 1,2 mm Breite, welcher mit Spaltverschlußmasse auszufüllen war.The cut flexographic printing plate was then detached from the adhesive sheet 1 and applied to a printing cylinder (circumference: 40 cm) using a 0.2 mm thick, double-sided adhesive sheet 2 measuring 40 cm × 60 cm so that the 60 cm long side of the printing plate came to lie parallel to the cylinder axis. As a result, there was a gap of 1.2 mm between the longitudinal edges of the printing form on the printing cylinder, which gap had to be filled with gap sealing compound.

Die Oberfläche der Flexodruckform wurde längs der zu verbindenden Kanten mit Klebstreifen abgedeckt.The surface of the flexographic printing plate was covered with adhesive strips along the edges to be joined.

Für die Herstellung der Spaltverschlußmasse wurde ein photopolymerisier­bares Gemisch aus, bezogen auf seine Gesamtmenge,
68,4 Gew.-%      eines flüsigen 1,2-Polybutadiens mit einem zahlenmittleren Molekulargewicht von 10 000 und einem Gehalt an Carboxyl­gruppen von, bezogen auf das Polybutadien, 2,5 Gew.% (flüssiges Bindemittel),
30 Gew.-%      Trimethylolpropantriacrylat (photopolymerisierbares Monomeres),
1,5 Gew.-%      Benzildimethylacetal      (Initiator der Photopolymerisation) und
0,1 Gew.%      2,6-Di-tert.-butyl-p-kresol (Inhibitor der thermisch initiierten Polymerisation)
verwendet.For the manufacture of the gap sealing compound, a photopolymerizable mixture of, based on its total amount,
68.4% by weight of a liquid 1,2-polybutadiene with a number average molecular weight of 10,000 and a carboxyl group content of 2.5% by weight, based on the polybutadiene, (liquid binder),
30% by weight trimethylolpropane triacrylate (photopolymerizable monomer),
1.5% by weight of benzil dimethyl acetal (initiator of the photopolymerization) and
0.1% by weight of 2,6-di-tert-butyl-p-cresol (inhibitor of thermally initiated polymerization)
used.

Dieses Gemisch wurde in eine Kartusche eingefüllt und über ein Schraub­gewinde durch eine 0,8 mm breite leicht gebogene Auslaufdüse in den Spalt gepreßt, wobei die Auslaufdüse längs des Spaltes geführt wurde. Dadurch entstand eine Füllung mit leichter Wölbung, welche über das Niveau der Druckformoberfläche hinausragte. Zum Teil war die Füllung auf die mit Klebstreifen bedeckte Oberfläche der Flexodruckform übergeflossen. Diese Anteile wurden zusammen mit den Klebstreifen von der Flexodruckformober­fläche entfernt.This mixture was poured into a cartridge and pressed into the gap via a screw thread through a 0.8 mm wide, slightly curved outlet nozzle, the outlet nozzle being guided along the gap. This resulted in a filling with a slight curvature, which protruded above the level of the printing form surface. In part, the filling overflowed onto the surface of the flexographic printing plate covered with adhesive strips. These parts were removed from the flexographic printing plate surface together with the adhesive strips.

Anschließend wurde die Spaltfüllung mit einer Polyethylenterephthalatfolie bedeckt und der gesamte Flexodruckzylinder wurde mit einem längs der Zylinderachse laufenden Polyethylenstrumpf umwickelt. Hiernach belichtete man das Gemisch im Spalt in einem Röhrenbelichter während 15 Minuten. Nach dieser Belichtungszeit, welche anhand von Vorversuchen ermittelt worden war, war das Gemisch soweit auspolymerisiert, daß die Reißdehnung RS (1,5 kp/2 cm) und die Reißdehnung RS/F (2 kp/2 cm) zusammen mit der Reiß­dehnung RF (6,5 kp/2 cm) die erfindungsgemäße Bedingung erfüllten. Die Reißdehnungen wurden mittels eines Instrons an 2 cm breiten Proben bei einem Abzugswinkel von 90° in bekannter Weise gemessen.The gap filling was then covered with a polyethylene terephthalate film and the entire flexographic printing cylinder was wrapped with a polyethylene stocking running along the cylinder axis. The mixture was then exposed in the gap in a tube exposer for 15 minutes. After this exposure time, which had been determined on the basis of preliminary tests, the mixture was polymerized to such an extent that the elongation at break R S (1.5 kg / 2 cm) and the elongation at break RS / F (2 kg / 2 cm) together with the elongation at break R F (6.5 kp / 2 cm) met the condition according to the invention. The elongations at break were measured in a known manner using an Instron on 2 cm wide samples at a take-off angle of 90 °.

Nach dem Entfernen des Polyethylenstrumpfes und der Polyethylen­terephthalatfolie wurde die Spaltverschlußmasse durch Reiben mit einem weichen Ledertuch oder einem Kunststoffschaber geglättet, in ihrer Dicke der Flexodruckform angepaßt und von der längs der verbundenen Kanten ver­laufenden Oberfläche der Flexodruckform entfernt. Hierbei wurde weder die Druckform noch die Spaltverschlußmasse in irgendeiner Weise geschädigt.After the removal of the polyethylene stocking and the polyethylene terephthalate film, the gap sealing compound was smoothed by rubbing with a soft leather cloth or a plastic scraper, the thickness of the flexographic printing plate was adapted and removed from the surface of the flexographic printing plate running along the connected edges. Neither the printing form nor the gap sealing compound was damaged in any way.

Mit dem fertigen Flexodruckzylinder wurden in einem üblichen Flexodruck­werk Plastikbahnen mit einer üblichen alkohollöslichen Flexodruckfarbe bedruckt. Selbst nach einer Auflage von 4.10⁴ Exemplaren war die Bild­wiedergabe von hervorragender Qualität. Der Spaltverschluß wurde im Druckbild kaum sichtbar. Nach Beendigung des Druckvorgangs wies die Spaltverschlußmasse keinerlei Deformationen, Risse oder Ablösungen auf. Die Spaltverschlußmasse konnte aber sehr leicht per Hand oder mit Hilfe eines Kunststoffspatels aus dem Spalt entfernt werden, ohne daß dabei die Flexodruckform zu Schaden kam.Plastic sheets were printed with the usual alcohol-soluble flexographic printing ink using the finished flexographic printing cylinder in a conventional flexographic printing unit. Even after a run of 4.10⁴ copies, the image reproduction was of excellent quality. The gap closure was hardly visible in the printed image. At the end of the printing process, the gap sealing compound showed no deformation, cracks or detachments. However, the gap sealing compound could very easily be removed from the gap by hand or with the aid of a plastic spatula, without the flexographic printing plate being damaged.

Nach dem Entfernen der Spaltverschlußmasse wurde die Flexodruckform vom Druckzylinder abgelöst und separat aufbewahrt. Für die Wiederverwendung wurde sie erneut mit einer Klebfolie 2 auf dem Druckzylinder fixiert und der Spalt zwischen ihren Kanten aufs neue in der vorstehend geschilderten Weise verschlossen.After the gap sealing compound had been removed, the flexographic printing plate was detached from the printing cylinder and stored separately. For reuse, it was fixed again with an adhesive film 2 on the printing cylinder and the gap between its edges was closed again in the manner described above.

VergleichsversuchComparison test

Das Beispiel wurde wiederholt, mit den Unterschieden, daß hierbei

  • 1. ein Zurichtezylinder ohne Kerbe verwendet wurde,
  • 2. die Druckform mittels der Klebfolie 1 auf dem Druckzylinder fixiert wurde und
  • 3. das flüssige photopolymerisierbare Gemisch während 25 Minuten vollständig auspolymerisiert wurde.
The example was repeated, with the difference that this
  • 1. a dressing cylinder without notch was used,
  • 2. the printing form was fixed on the printing cylinder by means of the adhesive film 1 and
  • 3. The liquid photopolymerizable mixture was completely polymerized for 25 minutes.

Nach dieser Belichtungszeit erfüllten die Werte der Reißdehnung nicht die erfindungsgemäße, sondern die folgende Bedingung:
RS/F (3 kp/2 cm) < RS (7 kp/2 cm) ≈ RF (6,5 kp/2 cm).After this exposure time, the values of the elongation at break did not meet the condition according to the invention but the following condition:
R S / F (3 kp / 2 cm) <R S (7 kp / 2 cm) ≈ R F (6.5 kp / 2 cm).

Die über das Niveau der Flexodruckform hinausragenden Anteile der Spalt­verschlußmasse mußten wegen deren hohen Zähigkeit und Festigkeit mit einem scharfen Messer weggeschnitten werden. Hiernach mußte die Spaltverschluß­masse mit einem Schleifgerät geglättet werden. Sowohl das Schleifen als auch das Schneiden war wegen der hohen Kautschukelastizität der Masse schwer durchzuführen; eine Beschädigung der Flexodruckform konnte hierbei nicht vermieden werden.The portions of the gap sealing compound that exceeded the level of the flexographic printing plate had to be cut away with a sharp knife because of their high toughness and strength. After this, the gap sealing compound had to be smoothed with a grinder. Both the grinding and the cutting were difficult to carry out because of the high rubber elasticity of the mass; Damage to the flexographic printing form could not be avoided.

Beim Drucken auf dem Flexodruckwerk waren daher bereits zu Beginn des Druckvorgangs Kratz- und Schleifspuren im Druckbild sichtbar. Nach einer Auflage von 4.10⁴ Exemplaren waren die Spaltverschlußmasse und die Kanten der Druckform leicht deformiert. Die Bildwiedergabe war insgesamt von geringerer Qualität als bei dem vorangegangenen Beispiel.When printing on the flexographic printing unit, scratches and sanding marks were therefore already visible in the print image at the start of the printing process. After a run of 4.10⁴ copies, the gap sealing compound and the edges of the printing form were slightly deformed. The overall image reproduction was of lower quality than in the previous example.

Nach dem Drucken konnte die Spaltverschlußmasse nur mit einem scharfen Messer durchtrennt werden. Dabei blieben Reste der Spaltverschlußmasse fest am Druckformmaterial haften. Bei dem Versuch, diese festhaftenden Teile abzuschneiden, abzureißen oder abzuschleifen wurden die Kantenbereiche der Flexodruckform stark beschädigt. Die Flexodruckform war daher für eine Wiederverwendung nicht mehr geeignet.After printing, the gap sealing compound could only be cut with a sharp knife. Remains of the gap sealing compound remained firmly attached to the printing form material. When trying to cut, tear off or grind away these adherent parts, the edge areas of the flexographic printing plate were severely damaged. The flexographic printing plate was therefore no longer suitable for reuse.

Claims (4)

1. Verfahren zum Verbinden der zugeschnittenen Kanten photopolymeri­sierter Flexodruckformen, welche Reliefschichten und dimensionsstabile Trägerfolien aufweisen, auf einem Druckzylinder durch a) Ausfüllen des Spaltes zwischen den zu verbindenen Kanten mit einem flüssigen photopolymerisierbaren Gemisch aus Bindemitteln, hiermit verträglichen photopolymerisierbaren Monomeren und Initiatoren der Photopolymerisation
und b) Auspolymerisieren des Gemisches unter einer fest aufliegenden, lichtdurchlässigen Abdeckung durch Bestrahlen mit UV-Licht,
dadurch gekennzeichnet, daß man a₁) die Druckformen vor dem Verfahrensschritt (a) mittels doppelseitiger Klebfolien 1 von gleicher Fläche wie die Druckformen auf Zurichtezylindern fixiert und auf die Druckzylinder passend zuschneidet, wonach man sie von den Zurichtezylindern und von den Klebfolien 1 ablöst, um sie anschließend mittels doppelseitiger Klebfolien 2 von gleicher Fläche wie die Druckformen und der 1,6- bis 2,6-fachen Dicke der Klebfolien 1 auf den Druckzylindern zu befestigen,
und daß man b₁) bei dem Verfahrensschritt (b) das Gemisch nur so lange partiell auspolymerisiert, bis für die Werte der Reißdehnung in dem Verbund aus fester Spaltverschlußmasse und Druckformmaterial die Bedingung
RS < RS/F « RF
erfüllt ist, worin
RS      die Reißdehnung der partiell auspolymerisierten Spalt­verschlußmasse,
RS/F      die Reißdehnung in der Grenzfläche zwischen der Spalt­verschlußmasse und dem Druckformmaterial und
RF      die Reißdehnung des Druckformmaterials
bedeutet. 1. Process for connecting the cut edges of photopolymerized flexographic printing plates, which have relief layers and dimensionally stable carrier films, on a printing cylinder a) Filling the gap between the edges to be connected with a liquid photopolymerizable mixture of binders, photopolymerizable monomers compatible therewith and initiators of the photopolymerization
and b) polymerizing out the mixture under a fixed, transparent cover by irradiation with UV light,
characterized in that one a₁) the printing forms before process step (a) by means of double-sided adhesive films 1 of the same area as the printing forms fixed on dressing cylinders and cut to fit the printing cylinders, after which they are detached from the dressing cylinders and from the adhesive films 1, in order to then use double-sided adhesive films 2 of the same area as the printing forms and 1.6 to 2.6 times the thickness of the adhesive films 1 on the printing cylinders,
and that one b₁) in process step (b), the mixture is only partially polymerized until the values for the elongation at break in the composite of solid gap sealing compound and printing form material are the condition
R S <R S / F «R F
is fulfilled in what
R S is the elongation at break of the partially polymerized gap sealing compound,
R S / F is the elongation at break in the interface between the gap sealing compound and the printing form material and
R F is the elongation at break of the printing plate material
means. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man nach dem Verfahrensschritt (a₁) und vor dem Verfahrensschritt (a) auf die längs der zu verbindenden Kanten verlaufende Druckformoberfläche Klebstreifen aufbringt, welche nach dem Verfahrensschritt (a) zusammen mit überstehendem, aus dem Spalt übergeflossenem Gemisch entfernt werden.2. The method according to claim 1, characterized in that after the method step (a₁) and before the method step (a) on the along the edges to be joined printing plate surface adhesive strips, which after the method step (a) together with protruding from which Gap overflowing mixture can be removed. 3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß man hierbei nach dem Verfahrensschritt (b) die Spaltverschlußmassen durch leichtes Abreiben oder Abschaben glättet, in ihrer Dicke den Druck­formen anpaßt und/oder von der längs der verbundenen Kanten verlaufenden Oberfläche der Druckformen entfernt.3. The method according to claim 1 or 2, characterized in that here after the process step (b) smoothing the gap sealing compounds by lightly rubbing or scraping, the thickness of the printing form adjusts and / or removed from the surface of the printing forms running along the connected edges . 4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß man für das Zuschneiden der Druckformen Zurichtezylinder mit mindestens einer achsparallel verlaufenden Kerbe und mindestens einer in senkrechter Richtung hierzu verlaufenden Kerbe verwendet, und daß man beim Zuschneiden die Druckformen und die Klebfolien mit einem in diesen Kerben geführten, achsparallel verschiebbaren, in einem Winkel von 0° und von 90° zur Zylinderachse fixierbaren, 100 bis 150°C heißen Messer mit trapezförmiger Schneide an der gewünschten Schnittstelle durchtrennt.4. The method according to any one of claims 1 to 3, characterized in that one uses for the cutting of the printing forme cylinder with at least one axially parallel notch and at least one perpendicular to this notch, and that when cutting the printing forms and the adhesive films with cut a 100 to 150 ° C hot knife with trapezoidal cutting edge at the desired interface, which is guided in these notches and can be moved axially parallel and fixed at an angle of 0 ° and 90 ° to the cylinder axis.
EP88105252A 1987-04-09 1988-03-31 Method of joining the cut-up edges of photopolymerised flexographic formes Expired - Lifetime EP0286020B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88105252T ATE65743T1 (en) 1987-04-09 1988-03-31 METHOD OF JOINING THE CUT EDGES OF PHOTOPOLYMERIZED FLEXO PRINTING FORMS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3712070 1987-04-09
DE19873712070 DE3712070A1 (en) 1987-04-09 1987-04-09 METHOD FOR JOINING THE CUT EDGES OF PHOTOPOLYMERIZED FLEXO PRINTING FORMS

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EP0286020A3 EP0286020A3 (en) 1989-04-26
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EP0406585A2 (en) * 1989-06-20 1991-01-09 BASF Aktiengesellschaft Method of filling and/or sealing the gaps, holes or interstices on printing plates attached to form cylinders
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ITMI20011164A1 (en) 2001-05-31 2002-12-01 Cielle Imballaggi Di Tommaso L METHOD FOR THE PRODUCTION OF SLEEVES FOR FLEXOGRAPHIC PRINTING AND SLEEVE OBTAINED
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EP0316597A2 (en) * 1987-10-26 1989-05-24 BASF Aktiengesellschaft Process for sealing cavities and/or interstices in printing plates fixed on cylinders
EP0316597A3 (en) * 1987-10-26 1990-03-28 BASF Aktiengesellschaft Process for sealing cavities and/or interstices in printing plates fixed on cylinders
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EP0406585A3 (en) * 1989-06-20 1991-07-31 Basf Aktiengesellschaft Method of filling and/or sealing the gaps, holes or interstices on printing plates attached to form cylinders
US11691408B2 (en) 2020-05-26 2023-07-04 Esko Software Bv System and method for designing and creating a printing plate

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EP0286020B1 (en) 1991-07-31
DE3863955D1 (en) 1991-09-05
ES2023457B3 (en) 1992-01-16
JPS63261364A (en) 1988-10-28
ATE65743T1 (en) 1991-08-15
DE3712070A1 (en) 1988-10-20
US4828641A (en) 1989-05-09

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