Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M7/00—After-treatment of prints, e.g. heating, irradiating, setting of the ink, protection of the printed stock
  • B41M7/02—Dusting, e.g. with an anti-offset powder for obtaining raised printing such as by thermogravure ; Varnishing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/40—Cover layers; Layers separated from substrate by imaging layer; Protective layers; Layers applied before imaging

Definitions

• the present invention relates to a wraparound covering for a printing or varnishing plate cylinder for the surface finishing of a printed substrate.
• a printed substrate there are various existing surface finishing processes for a printed substrate, the latter generally consisting of paper or cardboard, or plastic or metal material, and among such processes one consists in the application of an overprint varnish to the printed substrate.
• Overprint varnishes are typically water-borne or UV curable acrylics.
• the overprint varnishes are usually applied by using one or more varnishing units, which can also be positioned as final elements of the printing press and followed, if necessary, by ovens or lamps for drying or cross-linking the varnishes.
• Transfer of the varnish to the substrate takes place using a blanket or a varnishing plate, which serve the function of receiving the varnish and transferring it to the substrate.
• non-image areas areas having lower thickness, which are cut in the blanket or in the varnishing plate, are called "non-image areas".
• a blanket is mounted on the blanket cylinder and the surface thereof is generally constituted by a film made of PVF - polyvinyl fluoride (Tedlar ) - or of PVDF - polyvinylidene fluoride - for the purpose of giving the blanket a smooth, non-stick surface so as not to interfere with the metallised foil with which it comes into contact.
• PVF - polyvinyl fluoride Tedlar
• PVDF polyvinylidene fluoride
• a blanket such as this is in itself very costly and the process of adhesivation of the PVF or PVDF film is complicated and expensive. Moreover, a blanket such as this does not always guarantee the necessary- resistance to high levels of pressure.
• a blanket such as this can prove to be unwieldy and vulnerable to the point that during transport and assembly, surface folds can easily form, making it unusable, as it would replicate these folds on the metal foil, thereby spoiling the decoration.
• the technical task of the present invention is to realize a wraparound covering for a printing or varnishing plate cylinder for the surface finishing of a printed substrate that makes it possible to overcome the drawbacks of the previous art.
• an aim of the invention is to provide a covering of the type stated above that offers a wide flexibility of use for various processes for the surface finishing of a printed substrate, that also has improved resistance to abrasion and is less subjectable to keep the impression of the printing format, thereby ensuring a longer duration of use and a reduction in the time required for maintenance.
• Another aim of the invention is to provide a coating of the type stated hereinabove, which, in the field of overprint varnishing of a printed substrate, has an improved ability for the transfer of the varnish, together with improved dimensional stability suitable for making it reusable over time without any loss in precision.
• An additional aim of the invention is to provide a covering of the type stated above, which in the field of overprint varnishing of a printed substrate, offers easier washing thereof and thus a reduction in the time required for maintenance.
• a further aim of the invention is to provide a covering of the type stated above, which in the field of overprint varnishing of a printed substrate, has a printing surface with improved properties of chemical resistance to products used for washing.
• a further aim of the invention is to provide a coating of the type stated above, which in the field of application of a decorative metal foil to a printed substrate, proves to be simple in construction, as well as economical, easy to assemble, easy to handle, resistant and provided with properties characterising the surface consisting of smoothness and a non-stick quality that are optimal for the application.
• a wraparound covering for a printing or varnishing plate cylinder for the surface finishing of a printed substrate characterized in that a film of varnish is present in at least one zone of the surface thereof intended for contact with the printed substrate.
• the invention also provides a procedure for transferring an overprint varnish to a printed substrate, characterized in that there is applied to a varnishing cylinder a coating on which at least one zone is selected for transferring the varnish by application of a varnish film on said zone.
• This coating can be advantageously used in a printing press as the blanket or varnishing plate for the printing or plate cylinder of the varnishing unit, and in a cold foil laminator as the blanket for the printing cylinder suitable for applying a decorative metal foil to the printed substrate.
• the wraparound covering for a printing or varnishing plate cylinder for the surface finishing of a printed substrate has a film of varnish in at least one zone of the surface thereof intended for contact with the printed substrate.
• This film preferably has a thickness no greater than 400 ⁇ .
• the varnish is of the cross-linkable type having at least a wavelength in the ultraviolet range or in the range comprised between the ultraviolet and the visible region or in the visible range.
• the varnish may therefore be of a polymerizable type with light emitted by low- pressure fluorescent lamps or high-pressure mercury lamps, either pure or with Fe, Pb, As, Ga, In halides or other metals.
• the varnish may be of a polymerizable type with LED sources that emit at different wavelengths in a range of 200 to 450 nm.
• the varnish is preferably based on one or more base components selected from among aromatic and aliphatic epoxy acrylates and methacrylates, epoxidized soybean oil acrylates, acrylated polyesters, chlorinated acrylated polyesters, aromatic acrylated urethanes, aliphatic acrylated and methacrylated urethanes, acrylacrylates, polyether acrylates, amine-modified acrylated polyesters and methacrylated polybutadiene.
• base components selected from among aromatic and aliphatic epoxy acrylates and methacrylates, epoxidized soybean oil acrylates, acrylated polyesters, chlorinated acrylated polyesters, aromatic acrylated urethanes, aliphatic acrylated and methacrylated urethanes, acrylacrylates, polyether acrylates, amine-modified acrylated polyesters and methacrylated polybutadiene.
• the base components of the varnish are present in pure form or in an aqueous solution or aqueous dispersion, or in a mixture with one or more secondary components selected from among linear and cyclic alcohol monomers, lactones, glycols, bisphenols, pentaerythrols, mono-, di-, tri-, terra-, penta- and hexa-functional acrylated and methacrylated isocyanurates, silicones and acrylated melamines.
• a vamish such as this is polymerizable owing to photo initiators with a radical mechanism of the type such as alpha-hydroxy ketones, phenylglyoxylates, acylphosphine oxides, alpha amino ketones, benzophenone and derivatives thereof, benzyl dimethyl ketal, titanocene derivatives and oxime esters, camphorquinones or with a mixed system with resins with isocyanate functional groups.
• a radical mechanism of the type such as alpha-hydroxy ketones, phenylglyoxylates, acylphosphine oxides, alpha amino ketones, benzophenone and derivatives thereof, benzyl dimethyl ketal, titanocene derivatives and oxime esters, camphorquinones or with a mixed system with resins with isocyanate functional groups.
• the varnish may be based on one or more base components selected from among cyclic ethers, cycloaliphatic diepoxies, alcohols, and vinyl ethers.
• a varnish such as this is polymerizable with photoinitiators with a cationic mechanism of the type such as hexafluorophosphate salts of iodonium or su I ionium, pentafhiorophenyl. boranuides, sulfanyl phenyl sulfones and sulfonyl met ides or generators of photoacids like sulfonated oximes.
• This category includes the systems that react with mixed radical and cationic systems together.
• the polymerizable varnish may also make use of silicone and non-si I icone additives, fatty acids, polyurethanes, and polyacrylics.
• the varnish is water- or solvent-based, monocomponent or bicomponent, thermosetting or catalyzed.
• the vamish may be based on one or more base components selected from among acrolein resins, acrylamide resins, cyanoacrylic esters, haloacrylic esters, epoxy-acrylic urethane resins, acetal resins, alkyleneimine resins, al lene resins, al ly! resins, allyl-triazine resins, al ly! ethers, al ly ! esters, alkyl resins, acryl-modi fied alkyl resins, amine resins, polyester-based resins, epoxy resins, fluorocarbon resins, phenolic resins and polyurethane resins.
• base components selected from among acrolein resins, acrylamide resins, cyanoacrylic esters, haloacrylic esters, epoxy-acrylic urethane resins, acetal resins, alkyleneimine resins, al lene resins, al ly! resins, allyl-triazine resins, al
• the above-mentioned varnish may make use of silicone and non-si ! icone additives, fatty acids and mineral fillers.
• the covering in a printing press as the blanket or varnishing plate for the printing or plate cylinder of a varnishing unit for transferring an overprint varnish to the printed substrate.
• the basic structure of the blanket or the varnishing plate is common to currently known structures, and can thus provide an upper layer made of nitrile rubber, or polyurethane, or silicone or another material, a lower layer of polyester and a possible middle layer that is compressible, and in turn, possibly provided with a fabric for supporting the interface with the upper and/or lower layer.
• the basic structure of the blanket or of the varnishing plate is advantageously completed with the above-described film of varnish applied to the surface of the upper layer.
• the chemical/physical properties of the above-described film of varnish are such as to optimize the transfer of varnish to the printed substrate. In this manner, significant simplification of the production process is also achieved.
• the application of the film can take place in sheets or in reels according to all the known techniques, for example coating, spraying, flexo, rotogravure, curtain coating, reverse roll, silk screen printing or other techniques, including digital printing techniques.
• the silkscreen printing technique may be preferred, in that it makes it possible to apply a film of varnish of a large thickness and, if necessary, only in some selected parts of the printed substrate.
• non image areas can take place no longer by stripping the blanket or varnishing plate, but by selecting, thanks to serigraphic printing, the zones thereof that are suitable for transferring the varnish and that are selectively coated with the film of varnish.
• the film of varnish gives the specific surface properties consisting of smoothness and non-stick quality to the blanket.
• the application of the film of polymerizable varnish may take place in sheets or in reels according to all the known techniques cited hereinabove, for example coating, spraying, flexo, rotogravure, curtain coating, reverse roll, silkscreen printing or other techniques, including digital printing techniques.
• wraparound covering for a printing cylinder for the surface finishing of a printed substrate is susceptible to various modifications and variants falling within the scope of the most general inventive concept claimed.

Landscapes

• Printing Methods (AREA)
• Printing Plates And Materials Therefor (AREA)
• Details Or Accessories Of Spraying Plant Or Apparatus (AREA)
• Adhesive Tape Dispensing Devices (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (3)

Family Cites Families (9)

• 2012
  • 2012-01-18 IT IT000049A patent/ITMI20120049A1/it unknown
• 2013
  • 2013-01-14 WO PCT/EP2013/050551 patent/WO2013107707A1/en not_active Ceased
  • 2013-01-14 EP EP13700296.0A patent/EP2804765B1/de active Active

Non-Patent Citations (1)

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