EP2234815B1 - Contact or transfer roller - Google Patents

Description

The invention relates to a friction or transfer roller for a printing press, in particular offset printing machine, as defined in the claims. Furthermore, the invention relates to a printing press with a friction or transfer roller according to the invention.

Inking units of printing presses serve to transfer the printing means or the ink to be printed from a reservoir to a printing form, from which the image to be produced is usually transferred to a blanket cylinder and from there to the material to be printed, such as a paper layer. The inking system consists of a variety of different rollers, which work in pairs against each other to form a nip. A first type of rolls are transfer rolls with an elastomeric coating applied to the roll core. A second type of rolls are friction or hard transfer rolls in which the polymeric material cover is applied directly to the roll core, which is usually made of a metallic material, or to a hard elastic intermediate layer having a hardness of greater than 10 Shore D is applied. During operation of the inking unit, the distributor rollers carry out a traversing movement in the roll longitudinal direction in order to homogenize the ink film in the nip through the latter in cooperation with a soft-elastic transfer roller. Transfer rollers of the above-mentioned second type do not exert such a traversing movement. Transfer rollers of the first type in this case operate in the inking unit mostly against one or more of the friction or hard transfer rollers of the second type.

Essential for the functioning of the inking unit and optimum homogenization of the Verdruckmittels, occurrence of inhomogeneities of the Verdruckmittelfilms such. Cording effects, etc., and for the best possible print image here is that in their elastic properties exactly matched pairs of rollers each work against each other. The dynamic properties of the rolls are in view of the very high rotational speeds and the coordinated hardening of the mutually-working rolls in this context of essential importance, but also the hydrophilic or hydrophobic surface properties of the rolls. On the other hand, friction wheels and hard transfer rollers of the second type are subject to particularly stringent requirements with regard to the abrasion behavior and the mechanical stability. For these reasons, distributor rollers or hard transfer rollers are usually used with hard rubber or Rilsan covers. The above requirements are thus met by the construction of the inking unit with the above-mentioned rollers of the first and second types, each having a fundamentally different function in the inking unit.

Rollers of the first type have already been variously optimized in terms of their surface properties, in particular with regard to the optimization of the printed image, the optimization of the colorant transport in the inking unit, etc. For this purpose, variously proposed containing elastomeric materials to use fluorinated polyolefins.

Nevertheless, there is still a need to further improve the colorant transport in the printing unit in the direction of an optimized print image, to make the printing process less susceptible to interference, to minimize corrective interventions in the printing process and, in particular, also the emulsifying behavior of the printing medium in printing presses which produce an inking unit Use combination with at least one dampening unit, continue to improve.

Furthermore, from the EP 942 833 B1 a roller for color processing with a coating of a polymeric material or reactive resin is known, which has a layer thickness which is substantially less than 500 microns. In particular, the coating may consist of a thermosetting phenolic resin or polyurethane resin. This allows a good heat transfer from the Verdruckmittel done to the roll core. However, although the roller surface has some oleophilicity, the above-mentioned problems using such rollers can not be solved.

The US 4,198,739 and the DE 2 227 485 describe rollers with surfaces of high polymers such as FEP or PTFE. The US 4,178,850 and the EP 1 266 700 A2 describe rollers with covers made of elastomeric materials such as fluoroelastomers.

The invention has the object of providing an inking unit or to be used in this rollers, which solve the above problems. This object is achieved by a roller according to claim 1 and an at least one such roller containing inking or printing unit, wherein the roller is designed as a distributor roller or hard transfer roller.

Surprisingly, an improvement of the printed image and also the Verdruckmitteltransportes within the printing unit is observed using the rolls according to the invention, the Also significantly reduced irregularities in the printing process and allows a more even machine operation. This applies in particular even if the rolls according to the invention work against soft-elastic transfer rolls having a strongly hydrophobized surface, for example with a covering consisting predominantly or essentially completely of fluoropolymers or fluoroelastomers with regard to the polymeric material, as is known from US Pat DE 10 2004 054 425 are known. This is attributed to the fact that the trituration or homogenization of the fluid Verpressmittels in the nip is substantially facilitated by the fact that the opposing rollers have similar surface energies and no longer highly hydrophobized rollers (eg soft elastic transfer rollers) against more hydrophilic rollers such as Rilsan or Hartgummireiber work. By the adaptation of the surface energies of the two rolls at the nip, the homogenization as well as the Verdruckmitteltransport in the inking unit can be surprisingly significantly improved. This reduces interference in the printing process and allows for an increase in the printing speed and improved formation of the fluid film.

The hardness of the near-surface fluoropolymeric reference is ≥15 Shore D, and preferably ≥ 20-25 Shore D or ≥30-35 Shore D. Preferably, the hardness of the cover is in the range of 25-90 Shore D, e.g. in the range of 30-80 Shore D, more preferably in the range of 30 or 40 to 60 or 70 Shore D.

As an alternative to a hardness in ≥15 Shore D or in combination therewith, in the roll according to the invention the near-surface fluoropolymer coating may have a scratch hardness according to ISO 15184: 1998 (E) of 6B or harder, preferably a scratch hardness of 5B to 4B or harder, for example a scratch hardness from 2B to B or harder. In particular, the scratch hardness may also be F to H or harder, for example ≥ 2H or ≥ 3H or ≥ 4H. The scratch hardness is determined by a hardness test according to Wolff-Willborn. At the specified hardness Thus, there is a roll cover, which can not detect any scratch marks in a scratch test with a defined pencil according to ISO 15184. The specified pencil hardness thus corresponds to the hardest pencil, in which a corresponding scribe mark is just not recognizable. The scratch mark can be visible or palpable. The scribe produced in each case can consist in a plastic deformation of the roll cover (with even more scribe the scribe can destroy material and with the formation of a destruction of the cohesion of the roll material (cohesive fracture)), ie tearing the material generated, the crack generation optionally can take place down to the substrate. Like the scratch hardness, the Shore hardness also depends on the cohesive forces of the material, but both physical quantities are not directly correlated.

The scratch hardness of the cover thus determines the near-surface cohesive forces of the cover. It has been found that to solve the task of friction or transfer rollers are particularly advantageous, which thus have a reference top with defined cohesive forces, wherein the cohesive forces a scratch hardness of 6B or higher correspond to a surprising improvement according to the invention the homogenization and the Verdruckmitteltransportes to achieve in the inking unit.

The fluorinated polymer of the cover of the rolls according to the invention is a thermoset or energy-elastic material.

The fluoropolymeric cover of the roll according to the invention can thus be "non-elastic" or "practically non-elastic" and therefore fundamentally different from conventional elastomeric coverings. The term "non-elastic" may here be understood in the sense of "non-entropy-elastic" or "non-elastic or soft-elastic", the reference may thus optionally have an "energy elasticity". Starting from a T (temperature) - vs. logE (elastic modulus) diagram (xy representation) is the energy-elastic region at temperatures below the glass transition, and the entropy-elastic region at temperatures above the glass transition. There are several glass transition temperatures in this case, the glass transition next to the room temperature, if appropriate, may be understood here, in particular the glass transition next to the room temperature which has a higher transition temperature than room temperature. In particular, the cover material may be selected such that the glass transition temperature is above room temperature and / or above the operating temperature of the roll cover. The glass transition temperature (defined by the inflection point) may be ≥ 20-30 ° b, ≥ 40-50 ° C or ≥ 60-70 ° C or possibly ≥ 80-90 ° C, at temperatures of 20-30 ° C, 40-50 ° C, 60-70 ° C and / or optionally also 80-90 ° C, the fluoropolymeric cover may thus be energy elastic. The glass transition temperature may be less than or equal to 250-300 ° C, or may be ≤ 125-150 ° C or ≤ 250-300 ° C, and may generally be below or above the decomposition temperature of the polymeric coating material , In particular, the upper limit of the glass transition temperature may also be ≤30-50 ° C or about room temperature (22 ° C). If an interlayer of a polymeric material is provided between the fluoropolymeric lining and the roll core (thus being different from the tie layer), it may also be at operating conditions of the roll or at room temperature or at temperatures of 20-30 ° C, 40-50 ° C, 60-70 ° C or possibly also 80-90 ° C "hard-elastic" or "energy-elastic" and thus differ from conventional soft-elastic ("entropy-elastic") intermediate layers. The modulus of elasticity of the polymeric (hard elastic) intermediate layer may be greater than that of the fluoropolymer near-surface coating at room temperature, at 30 ° C, at 50 ° C, at 70 ° C, and / or the operating temperature of the roll.

It is understood that the cover can preferably be applied directly on the hard elastic intermediate layer, preferably using a primer layer.

The roll may have a surface roughness (ie, averaged Roughness Rz determined according to DIN EN ISO 4287) of ≤ 17-20 μm Rz, preferably ≤ 12-15 μm or ≤ 7-10 μm, more preferably ≤ 4-5 μm or ≤ 2-3 μm or ≤ 1 μm.

The surface energy of the roll according to the invention or that of the roll cover which can provide the roll surface is thus preferably ≦ 25 mN / m, particularly preferably ≦ 22-23 mN / m or ≦ 20-21 mN / m, so that directly from the roll surface no water is adapted. As a result, the emulsion is a total of less water. This is a significant advantage over the materials previously used in such rolls with thin coating. Although the coatings were used to hydrophobize the roll surface so that they do not absorb more water but paint, they apparently still adapted water to a relevant extent, as did Rilsan coated rolls. As has been shown within the scope of the invention, this is probably the cause of process instabilities that can be eliminated by the non-water adaptive rolls of this invention.

Furthermore, it was surprisingly found that deposits of silicon complexes on the rolls according to the invention can be significantly reduced. In this case, the cause of the emergence of such silicon-containing complexes, which lead to unstable and defective emulsions of Verdruckmittels, ultimately not clarified. The formation of the silicon complexes depends in a complicated manner on the printing materials used in each case as well as the used to be printed materials such as paper types. At the same time, the formation of such silicon complexes on the soft-elastic transfer rollers, which work against the rolls according to the invention, is reduced, which suggests a certain "seeding behavior". Furthermore, surprisingly often deposits of calcium complexes on the roll surfaces can be significantly reduced by means of the rolls according to the invention. The reduction of the deposition of such silicon complexes Partially independent of the reduction of undesirable deposits such as calcium complexes can be carried out, and conversely, under certain pressure conditions, deposits of both silicon and calcium complexes on the roll surfaces can also be prevented by means of the rolls according to the invention. These silicon and calcium deposits can occur together, but sometimes also independently, the causes of these deposits are not yet understood. These advantages of the rolls according to the invention are observed especially in rolls with coatings of duromer material such as highly crosslinked fluorinated polyurethane resins, epoxy resins, polyester resins, polyether resins and / or acrylate resins. Similarly, these advantages are observed when the cover contains highly crosslinked, non-elastic materials containing as monomers fluorovinyl ether or fluoroalkyl vinyl ether, especially perfluorovinyl ether or perfluoromethyl vinyl ether, or mixed halogenated monomers such as chloro-fluoro-substituted olefins such as chlorotrifluoroethylene or only partially halogenated monomers such as Contain hydropentafluoropropylene, as well as for high polymer compounds containing or consisting of tetrapolymers having a fluorine content of> 67 wt .-%, for example up to 60 wt .-% fluorine based on the polymer weight.

The ink fountain rollers according to the invention with low surface tension thus hold no salt (such as calcium and / or silicon complexes) more firmly on the surface, can not be hydrophilized and provide a durable low-water "dry" stable emulsion. A back splitting of fountain solution from the printing plate in the inking unit, where it is in principle undesirable and can lead to incorrect emulsions (color or oil in water emulsion) is thus prevented. In contrast, conventional rollers lead water and salts into the inking unit, the salts (eg calcium complexes) settle on evaporation of the water on rollers with a relatively high surface tension and increase in this way the surface tension the wetted rollers, hydrophilize the surfaces and thus increase the water balance and demand of the inking unit, which can ultimately lead to a faulty emulsion and a breakdown of color transport.

Furthermore, the emulsification behavior of the printing medium in connection with a dampening solution used is further optimized by the rollers according to the invention and the water consumption in the color unit is further minimized.

Furthermore, the cleanability of the pressure chair or inking unit as a whole is surprisingly substantially facilitated by the rubbing or transfer roller according to the invention, even if already soft-elastic transfer rollers having strongly hydrophobic coatings with e.g. high fluorine content can be used in the inking unit. This is attributed to the fact that compared to conventional distributor rollers the Verdruckmittel or contaminated with this washing medium in the cleaning no longer remains on the distributor roller or even enriches on this, but that due to the very low surface energy, the printing medium very quickly from the hard Reiber - Or transfer roller removed and thus can be completely removed from the printing unit.

The cover preferably provides the roll surface or is optionally provided with a thin surface coating, which preferably has no significant influence on the surface hardness of the cover and may have a layer thickness of ≤ 7-10 μm, ≤ 3-5 μm or ≤ 1-2 μm , The reference having a hardness of ≥ 15 Shore D can thus also consist of a different material than the possibly provided elastic (hard-elastic or energy-elastic) intermediate layer, in particular of a different base material or different polymers of the base material. The next closest to the roll surface cover may generally have a greater hardness than the elastic intermediate layer. The elastic intermediate layer may in this case for example consist of a hard rubber whose fluorine content is substantially lower than that of the cover, preferably <50%, <25% or <5-10% of that of the cover. Preferably, the intermediate layer is fluorine-free or halogen-free. In particular, the intermediate layer may have a lower hardness than said reference, but optionally also an approximately equal or greater hardness. In particular, the reference used in each case over its layer thickness and / or axial extent is homogeneous, in particular with regard to its composition and / or its physical properties, for example, the hardness and / or the fluorine content. However, it is of course possible to provide fillers, additives and other components which are preferably distributed homogeneously in the cover, which preferably do not bring about any gradients of the composition and / or the physical properties over the layer thickness of the cover. The cover can be connected to the elastic intermediate layer or the core in each case by means of a bonding agent layer.

The cover according to the invention consists of more than 50 wt .-% of fluorinated polymers. Preferably, the cover consists of a fluorinated polymeric material, which in each case based on the polymeric constituents or on the total weight of the cover in a proportion of ≥ 75-80, ≥ 90, ≥ 95 or ≥ 98 wt .-% or at least about 100 Wt .-% may be present. Other polymeric moieties may be e.g. non-elastic components with possibly different hardness or other properties.

The fluorinated polymer according to the invention is a thermoset or energy-elastic material. In one embodiment, the fluorinated polymer of the cover is a thermoset material, ie, the polymer is present as a thermally irreversible or covalently cross-linked macromolecule with an amorphous structure and high crosslink density. The polymer content with thermoelastic properties at room temperature and / or the range or polymer content with thermoelastic softening in conventional or still possible operating conditions of the roller is preferably practically negligible or not present.

Preferably, the thermosetting polymer has a high degree of crosslinking, for example, based on a decomposition of the polymer backbone into monomer units, e.g. in units of monomers having a C atom number of ≦ C4-C6 or ≦ C7 or ≦ C8 monomer units, ≥ 10-15 or ≥ 20-25, preferably ≥ 30-40 crosslink sites per 100 monomers, wherein the crosslink sites are preferably thermally irreversible or covalent are. It is understood that the monomer units may represent the monomers present in this case in a retrosynthetic manner, it being possible to prepare the thermosetting polymers as usual by polymerization of a large number of oligomers containing monomers.

It has proved to be particularly advantageous if the thermosetting polymers have one or more polymers selected from the group of polyurethane resins, polyester resins, epoxy resins, polyether resins, polycarbonate resins or acrylate resins. Despite the presence of the functional urethane, ester, epoxy, ether, carbonate or acrylate groups such thermosets are highly hydrophobic due to a sufficiently high fluorine content and have a very low tendency for deposition of silicon complexes and also a low tendency to adhesion the Verdruckmittels. Optionally, these materials may also have thermoplastic components.

According to a further advantageous embodiment, the fluorinated polymer of the cover may be a non-elastic highly crosslinked polymer, for example a copolymer (including terpolymer or tetrapolymer, etc.) containing one or more monomers from the group vinylidene fluoride (VDF), hexafluoropropylene (HFP), chlorotrifluoroethylene , Hydropentafluoropropylene, tetrafluoroethylene (TFE), perfluorovinyl ether, perfluoromethyl vinyl ether. In particular, the polymer may be 1,1-dihydroperfluorobutyl acrylate and / or vinyl fluoride comprise or consist of monomer units. The copolymers (terpolymers, tetrapolymers, etc.) may each be block polymers, random polymers or graft polymers.

The polymer of the cover may contain or at least substantially consist of at least one or more copolymers, terpolymers and / or tetrapolymers or higher copolymers, wherein the various co-, ter- and tetrapolymers may also be present in combination.

Illustrative are one or more of the copolymers vinylidene fluoride (VDF) -hexafluoropropylene (HFP), VDF-chlorotrifluoroethylene, VDF-hydropentafluoropropylene, tetrafluoroethylene (TFE) propylene, TFE-VDF copolymers, TFE-VDF, vinylidene fluoride-chlorotrifluoroethylene copolymer.

The polymer of the cover may contain or at least substantially consist of terpolymers of the type VDF-HFP-TFE, VDF-TFE-perfluorovinylether, PFE-perfluoromethylvinylether (PMVE) propylene, VDF-TFE-propylene, VDF-TFE-hydropentafluoropropylene, vinylidenfluoride- tetrafluoroethylene-Perfluromethylvinylether copolymer.

The fluorinated polymer of the cover may further comprise or consist of tetrapolymers, such as. VDF-HFP-TFE-PMVE or VDF-HFP-TFE-ethylene.

The fluorinated polymers used in the cover may thus comprise non-perfluorinated monomer units, for example chlorotrifluoroethylene, hydropentafluoropropylene or ethylene. Alternatively or additionally, the fluorinated polymeric monomer units may contain functional ether groups such as perfluorovinyl ether and / or perfluoromethyl vinyl ether.

The copolymers used can have a fluorine content of up to 65 to 65.5 wt .-% fluorine, for example, a fluorine content of up to 67 wt .-% (especially when using terpolymers) or of up to 67-69 wt .-% (especially when using tetrapolymers). The data relate in each case to the corresponding polymer weight.

When the fluoropolymer of the reference contains vinyl fluoride and / or vinylidene fluoride monomer units, the proportion of the monomers, based on the total weight of the polymer, may each be 5-90% by weight, e.g. ≦ 75% by weight, ≦ 50 or 30% by weight. The content of vinyl fluoride and / or vinylidene fluoride in the fluoropolymer may be in the range of 5-40% by weight or 10-40% by weight or 10 to 30% by weight.

Alternatively, or in addition to the content of vinyl fluoride and / or vinylidene fluoride in the fluoropolymer, at least one, two or more monomers of another -C = C unsaturated monomer unit may be included, the monomer each containing fluorine optionally together with another halogen such as in particular Chlorine, in particular in each case perfluorinated. The unsaturated monomers may be one or more monomers selected from the group tetrafluoroethylene, trifluoroethylene, trifluorochloroethylene, pentafluoropropylene, pentafluorochloropropylene, hexafluoropropylene. In addition or as an alternative, one or more of the monomers may be selected from the group consisting of fluoropropyl vinyl ether, fluoroethyl vinyl ether or fluoromethyl vinyl ether, in particular in each case as perfluoro compound, it also being possible for one or more fluorine atoms to be replaced by another halogen, in particular chlorine. One or more of the monomers mentioned above can each contain, individually or in total, in a proportion of 5 to 80% by weight, optionally ≦ 75 or ≦ 50 or ≦ 30% by weight, based in each case on 100 parts by weight of polymer of the cover be, for example in a range of 5-20 wt .-% or 10-20 wt .-%.

One, two or three of the copolymers HFP-VDF, TFE-VDF and / or TFE-HFP-VDF may be included in the cover at a level of 10-100% by weight, e.g. 5-90 wt .-%, preferably ≤ 80 or ≤ 75 or ≤ 50 wt .-%, each based on 100 parts by weight of fluoropolymer present. TFE-VDF, HFP-VDF and / or TFE-HFP-VDF may each be contained in a proportion of ≥10% by weight or ≥20 or ≥30% by weight, based on the polymer of the cover.

The framework of the preferably duromeric fluoropolymer and / or other polymeric components of the coating, preferably all of the polymers, may each be free of heteroatoms, in particular free of ether groups, free of O, N and / or Si atoms. The skeleton of the polymers can each be a virtually pure carbon skeleton. In particular, the fluoropolymer and other polymeric components may be substantially or completely free of side groups containing O, N and / or Si functional groups, such as ether groups, or free of heteroatoms, other than halogen. This refers in each case preferably to the uncrosslinked polymer without consideration of corresponding crosslinkers or other auxiliaries. However, the fluoropolymer preferably contains halogenated, in particular perhalogenated, alkyl side groups, it being possible for each halogen to be fluorine, in particular -CF ₃ and -C ₂ F ₅ groups.

There may be less than 10 or 5%, preferably less than 1% or 2% of the atoms of the fluoropolymer, each based on 100 carbon atoms of the polymer in unsaturated groups, more preferably the fluoropolymer has virtually no unsaturated groups.

The cover may optionally also contain non-fluorinated polymers, for example in a proportion of ≦ 20% by weight, preferably ≦ 10% by weight, more preferably ≦ 5% by weight, based in each case on 100 parts by weight of polymer.

According to a further advantageous embodiment, the fluorinated polymer may be one or a combination of fluorosilicone resins. The alkyl, aryl and / or chloroalkyl groups of these silicone resins are at least partially fluorinated, optionally perfluorinated with respect to some or all of the monomers used. The crosslinking of these resins can take place via trifunctional organosilanes, eg organotrichlorosilanes, or silicon tetrachloride. Alternatively or additionally, the siloxanes can be crosslinked by unsaturated organic groups, in particular unsaturated CC groups, such as vinyl groups, butadine radicals or the like. These silicone resins may include or consist of fluorinated polydiorganosiloxanes in which the organic groups may be partially fluorinated or perfluorinated. Thus, the polymeric fluorosilicone components polydiorganosiloxanes of the general formula XO- (SiO _x R ¹ R ² - (SiO) _y R ³ R ⁴ -X, where the radicals R ¹ to R ^{4 may be} fluorinated or perfluorinated alkyl, aryl or alkenyl radicals and x is a suitable end group, in particular hydrogen, methylphenylvinylsilyl or silyl radicals having CC unsaturated groups, which polymers may be highly crosslinked via unsaturated CC groups. Accordingly, other siloxane units -O- (SiO) _z R ⁵ R ⁶ , etc. can also be used. The alkyl, aryl or unsaturated hydrocarbon groups may each have 1 to 20 carbon atoms, preferably ≥ 2 or 4 C atoms, optionally also 2 to 10 or 4 to 6 C atoms vinyl-terminated or terminated by other unsaturated hydrocarbon groups through which the polymeric strands are crosslinked In particular, fluorosilicone polymers may form interpenetrating networks, or functionalized polysiloxanes may be crosslinked with organic fluoropolymers, eg, fluoropolymers.

According to a further advantageous embodiment, the fluorinated polymers are one or more fluorothermoplastics, for example ECTFE (ethylene-chlorotrifluoroethylene copolymers), ETFE (tetrafluoroethylene-ethylene copolymers), FEP (tetrafluoroethylene-hexafluoropropylene copolymers), PFA (tetrafluoroethylene-perfluorovinyl ether copolymers), PVDF (polyvinylidene fluoride), PVDF copolymers (copolymers with hexafluoropropylene HFP or Chlorotrifluoroethylene CTFE), PTFE (polytetrafluoroethylene) / or THV (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride polymers). The thermoplastics may thus generally include, but are not limited to, chlorotrifluoroethylene or other mixed haloalkane units, tetrafluoroethylene, hexafluoropropylene, perfluorovinyl ether, polyvinylidene fluoride as monomers. Also suitable as monomers are alkylene units, for example ethylene, propylene or butylene. The monomers may each be partially or perhalogenated or fluorinated. The abovementioned copolymers or terpolymers may each be random polymers, block polymers, graft polymers or the like.

According to a further embodiment, the fluorinated polymers used may be fluoropolymer lacquers, which may each be water-based or solvent-based lacquers or powder lacquers. The lacquers contain in each case at least one or more binders and usually also mostly suitable fillers and additives.

The binders, each fluorinated or perfluorinated, may for example be selected from the group of acrylate resins, aldehyde resins, acyldharze, amido resins, amino-epoxy resins, amino resins, benzoguanamine resins, bituminous resins, cellulose resins, cellulose acetate, cellulose acetobutyrate, cellulose acetopropionate, cellulose nitrate, diamine resins, Epoxy acrylates, epoxy resins, epoxy resin esters, epoxy resin / tar combinations, epoxy methacrylates, acetate resins such as ethylene / vinyl acetates, fluoropolymer resins, formaldehyde resins including modified resins, urea / formaldehyde resins, urea resins, hydroxyacrylates, indene resins, isocyanate resins, ketone resins, hydrocarbon resins, Rosin rosin esters, rosin resins, maleate resins, melamine / formaldehyde resins, melamine resins, methacrylates, natural resins, phenol / formaldehyde resins, phenolic resins, phenoxy resins, polyacrylates, polyacrylic esters, polyamide resins, polyamines, polyaminoamides, saturated and unsaturated polyesters, polyester acrylates, polyether acrylates, polyethylene (also halogenated or chlorinated), polyhydroxy resins, polyisocyanates, polymethyl methacrylates, polymethacrylates, polyolefins (including halogenated or chlorinated), polyol resins, polypropylenes, polysiloxane resins, polystyrenes, polyurethane resins, polyurethane / tar combinations, polyvinyl resins, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride (chlorinated), Polyvinylidene chloride, polyvinylidene fluoride, resinates, silanes, silicone resins, siloxane resins, urethane resins.

The proportion of binders in the paint, based on the anhydrous or solvent-free composition, is preferably ≥ 25-30% by weight, ≥ 50-55% by weight, preferably ≥ 60-70% by weight, optionally ≥ 75-80 Wt .-% or even ≥ 90 wt .-%.

It is understood that each one or more of the above-mentioned fluorinated polymers may be included in the reference. Preferably, the at least one of the fluorinated polymers described above forms a continuous matrix of the cover. The cover can extend in each case in the circumferential direction and / or in the longitudinal direction of the roller over at least approximately the entire extent of the roller. Preferably, said fluorinated polymer forms the cover at least substantially or completely (based on the polymeric constituents), apart from conventional additives such as fillers, additives and / or colorants, etc.

The proportion of polymeric constituents, in particular of the abovementioned fluorinated polymers, may be ≥ 50 to 60% by weight, ≥ 70 to 75% by weight, ≥ 80 to 90% by weight, ≥ 95 to 98% by weight or about 100 wt .-% based on the total weight of the polymeric ingredients total or relative to the total weight of the cover.

The cover can contain other halogens, in particular chlorine, in addition to fluorine. The fluorinated polymer of the cover may be perhalogenated or perfluorinated. Preferably, ≥50%, ≥60%, ≥70%, ≥75%, ≥80%, ≥90%, ≥95-85% or about 100% of the H atoms of the polymers forming the reference are halogen atoms, in particular fluorine atoms , replaced, preferably ≥ 50%, ≥ 75 to 80%, ≥ 90% or about 100% of the halogen atoms of the fluorinated polymer fluorine atoms (each at .-%). Alternatively, a significant hydrogen content, e.g. as carbon-bonded hydrogen. Thus, based on the sum of the C-bonded hydrogen and halogen or fluorine atoms, the proportion of hydrogen atoms ≥ 0.5-1 at .-%, ≥ 2-4 at .-%, ≥ 7.5-9 or to 10 -11 at.% Or even ≥ 20-25 at.%.

The fluorine content of the fluoropolymer or the total reference may be about 60 - about 74 wt%, preferably about 64 - about 72 wt%, e.g. about 66 to about 70 wt .-%, in particular about 68 wt .-% amount.

The respective fluorinated polymer of the cover or the cover as a whole may additionally contain fillers, additives and / or colorants and optionally further components.

In each case one or more fillers may be provided from the group of aluminum oxides and hydroxides, aluminum silicates, aluminum trihydrate, inorganic oxides, calcium carbonates (natural or precipitated), carbonates such as barium or calcium carbonate, Christobalites, dolomite, fibrous materials such as glass fibers, glass and mineral wool , Graphite, feldspars, fluoropolymer powders (eg PTFE and PFA powder), silicates, phyllosilicates such as mica, skeletal silicates (the silicates can contain as cation at least predominantly sodium, potassium, magnesium and / or calcium), hydrogels , Kaolin, carbon fibers, Silica, silica gels, chalk, silica, corundum, magnesium hydroxides, hollow microspheres, quartz eg as quartz powder, carbon blacks, sand, silicas, Silikatfüllstoffe, sulfates such as barium or calcium sulfate, superabsorbent, talc, titanium dioxides, wollastonites, without being limited thereto.

The fillers may optionally be surface modified, e.g. be used in hydrophobicized, form. Optionally, the cover may be free of soot, silicates, sand and / or quartz. Furthermore, the cover may be free from fibrous or fibrous components, hollow spheres and / or coarse-particulate fillers having a particle size of ≤ 25 μm or ≤ 10-20 μm. The average or maximum particle size of the fillers is preferably ≦ 5-7.5 μm, ≦ 2-3 μm or particularly preferably ≦ 1-1.5 μm or ≦ 0.5-0.75 μm, if appropriate also ≦ 0.3 μm ,

As additives, one or more of the following group may be respectively provided in the polymer or paint or in the general terms: adsorbents, algicides, antioxidants, anti-sagging agents, anti-settling agents, anti-flooding agents, antiblocking agents, anti-thickening agents, anti-fouling agents, anti-graffiti additives, anti-sticking agents, anti-skinning additives, anticratering agents , Brighteners (optical), bactericides, dispersing additives, emulsifying additives, degassing additives, deaerators, defoaming agents, flame retardants, fungicides, gelling agents, gloss improvers, slip additives, adhesion promoters, hydrophilizers, water repellents, catalysts, preservative additives, corrosion inhibitors, conductivity additives, light stabilizers, matting additives, wetting additives, open-time Additives, photoinitiators, rheology additives, sandability improvers, siccatives, soft-touch additives, stabilizers, radiation curing additives, substrate wetting additives, thixotropic agents, T solvents, UV absorbers, UV stabilizers, thickeners, leveling agents, crosslinking agents, viscosity stabilizers, waxes.

One or more colorants may be provided in each case from the group of effect pigments, inorganic and organic color pigments, soluble dyes, functional pigments, pigment preparations, black pigments, white pigments.

The filler content of the cover can be ≦ 75 or ≦ 45-50 wt .-%, preferably ≦ 30-40 wt .-%, ≦ 20-25 or ≦ 19 wt .-%. The filler content of the cover is particularly preferably ≦ 7.5-10% by weight or ≦ 4-5% by weight. The filler content of the cover is particularly preferably ≦ 1 to 2% by weight or the cover is essentially filler-free. The weights are based on the total weight of the polymeric components of the cover or on the weight of the cover as a whole. The same can apply to the proportion of the further additives or colorants in the reference composition, wherein the sum of the contents of additives and colorants preferably makes up ≦ 25% by weight of the reference.

The layer thickness of the cover of the fluorinated polymer can be ≦ 200 μm, preferably ≦ 90-100 μm, particularly preferably ≦ 70-80 μm or ≦ 50-60 μm. The layer thickness of the cover can be ≥ 2-3 μm or ≥ 5-10 μm, preferably ≥ 20-30 μm. The layer thickness of the cover can be in particular in the range of 40-70 microns. The cover may in this case be made homogeneous across its thickness, i. no gradient with respect to a property such as Degree of crosslinking, hardness, content of other components or the like over its thickness. The layer thickness is preferably chosen such that it enables the best possible heat removal from the roll surface to the roll core.

The layer thickness of an intermediate layer between the fluoropolymeric cover and the roll core, such as an adhesion promoter layer, may be ≦ 50-75 μm, preferably ≦ 40-45 μm or ≦ 30-35 μm, particularly preferably ≦ 20-25 μm. The layer thickness of the intermediate layer may be ≥ 2-3 μm or ≥ 5-7 μm, for example ≥ 10 μm. Generally, the layer thickness of the intermediate layer may be smaller than that of the fluoropolymeric cover.

The layer thickness of the total cover of fluoropolymeric cover and intermediate layer may be ≦ 200 microns, preferably ≦ 180-150 microns, more preferably ≦ 120-100 microns or even smaller ≦ 75-90 microns.

Preferably, the fluoropolymer cover is applied directly or optionally by means of an intermediate layer, in particular a primer layer whose thickness is preferably less than that of the cover, on the rigid, undeformable roll core. The roll core may consist of a metal. The intermediate layer preferably has no fiber constituents and / or fillers. Preferably, according to one embodiment, no further intermediate layer is provided between the fluoropolymeric cover and the roll core, apart from the adhesion promoter layer.

If the roller according to the invention has a hard-elastic intermediate layer, then the layer thickness thereof is preferably equal to or greater than that of the cover with a hardness of ≥ 15 Shore D, but may possibly be smaller. The layer thickness of the intermediate layer may in this case be up to 100 μm or up to 200-300 μm or up to 500 μm, up to 1-2 mm or up to 5 mm or more. Optionally, the layer thickness of the intermediate layer may also be smaller than that of the cover. Such an intermediate layer worsens the heat transfer from the roll surface to the roll core, which is usually undesirable, but may be provided if optimal heat transfer is not absolutely necessary and other properties of the roll cover as a whole are to be optimized. The hard elastic intermediate layer may have a hardness in the Shore D range, for example ≥10-15 Shore D or ≥20 Shore D.

The hardness of the hard elastic intermediate layer can be ≥ 10-15 Shore D, for example, also ≥ 20-30 Shore D, preferably the hardness ≤ 50-60 Shore D or ≤ 70-80 Shore D. The hardness of the hard elastic intermediate layer may be in the range of 30-40 Shore D. The hardness of the hard elastic Intermediate layer is preferably less than the hardness of the fluoropolymeric cover applied thereto, it may also be at least about the same, if appropriate, for example with a relative deviation of ≤ ± 15-20% or ≤ ± 5-10%. The term "hard-elastic" can also be understood in the sense of "duromerelastically" or "energy-elastic", so that the intermediate layer is therefore "non-entropy-elastic".

The fluoropolymeric cover provided near or on the roll surface preferably extends over at least approximately the entire width of the effective area used in the printing operation, e.g. is active during the rubbing process or serves as a pressure medium transfer surface. Preferably, the fluoropolymeric cover extends fully around the roller.

Furthermore, the invention relates to a printing press with at least one or more rollers according to the invention. Preferably, all of the distributor rollers and / or all transfer rollers with a cover having a hardness of ≥ 15 Shore D are designed as rollers according to the invention. The rolls according to the invention can also be provided in the cleaning device of the respective inking unit or the printing machine, but they are preferably arranged in the inking unit of the printing press.

Preferably, in the respective printing press or the inking unit, the rollers according to the invention each work against at least one or more rollers with a cover of a polymeric material of lower hardness. Each of these rollers may also be provided with a highly hydrophobic cover, in particular with an elastic fluoropolymer or with a cover containing such elastic fluoropolymers, in particular as the matrix material of the cover. Such rolls are from the DE 10 2004 054 425 is known, which is hereby incorporated by reference in its entirety. The covers of these rolls generally have a hardness of ≥ 20 Shore A and ≤ 80 Shore A, usually in the range of 20 to 50 Shore A.

The crucial in the context of the invention is thus that the surface tension of the inventive hard (preferably thermoset or thermoplastic related) rollers are provided with about the same low surface tension as the soft (elastomer related) rollers, the inking unit, in particular with an elastic fluoropolymer such. a fluororubber may be coated. The surface tension of the rolls according to the invention and of the soft rolls working against each other can thus each be ≦ 40-50 mN / m, preferably ≦ 25-30 mN / m or ≦ 15-20 mN / m. The relative difference of the surface tensions of the rolls according to the invention and the soft-elastic counter-rolls can be ≦ 75-100%, preferably ≦ 30-50% or ≦ 20-25%, more preferably ≦ 15-10%. All elements of the color chair can thus be equipped with compatible approximately the same low surface tension.

Preferably, the cover of the roll according to the invention consists essentially completely of the fluorinated polymer described, apart from any fillers, additives and / or colorants or other auxiliaries.

The invention will now be described by way of example and with reference to the figure.

According to a first embodiment, a distributor roller has a cover applied to a rigid core, for example a steel core, by means of a bonding agent layer, with a layer thickness of 80 μm and a hardness of 50 Shore D. The cover consists of a fluorinated polymer in the form of a thermoset, which may be a polyurethane resin, polyester resin, epoxy resin, acrylate resin or polyether resin. 95% of Carbon-bonded hydrogen atoms of the polymer are substituted by fluorine atoms. Based on 100 monomers of the polymeric material, there are about 30 covalent crosslinking sites.

A second embodiment relates to a roller according to the first embodiment, wherein the cover is applied here on a hard elastic intermediate layer of hard rubber, which has a layer thickness of 500 μ and a hardness of 20 Shore D. Such a roller can be used in particular as a transfer roller in the printing press.

According to a third embodiment, a distributor roller has a cover applied to a rigid roller core by means of a bonding agent layer with a layer thickness of 60 to 80 μm and a hardness of 55 Shore D. The cover consists of a highly cross-linked PFE-PMVE propylene terpolymer, wherein, based on 100 monomer units, there are about 30 cross-linking sites. The fluorine content of the cover is 65 wt .-% based on the polymer weight. The cover can be applied in particular in the form of an aqueous dispersion or a solution with organic solvents on the roll core.

The fourth embodiment is a modification of the third embodiment, wherein between the roll core and the cover, a hard elastic intermediate layer in a layer thickness of 200 microns with a hardness of 30 Shore D is applied.

According to a further embodiment, a cover made of a highly crosslinked fluorosilicone polymer in a layer thickness of 50 microns and a hardness of 40 Shore D is applied to the rigid core. The C6-C12 alkyl substituents of the silicone polymer are each perfluorinated. The silicone polymer is three-dimensionally crosslinked via unsaturated side groups, in particular vinyl groups, and / or trifunctional Si atoms. Optionally, the cover also on a hard elastic intermediate layer be applied from hard rubber, which may have a layer thickness of about 1 mm and a hardness of about 35 Shore D.

According to a further embodiment, a preferably usable as a distributor roller roller has a directly applied directly to the rigid roller core cover, which consists of a fluorothermoplastic, for example ECTFE or PVDF and a layer thickness of about 50 μ and a hardness of about 40 Shore D may have.

The covers according to the embodiments may each contain fillers and other additives, wherein the fillers may be provided, for example, up to 10-40 wt .-% based on the total weight of the cover material, without being limited thereto. The cover can also be free of fillers, however. Furthermore, the covers may comprise conventional additives which may be present in a proportion of up to 10-25 wt .-% based on the total weight of the reference material, without being limited thereto.

Is in the rollers according to the embodiments of the reference - optionally applied by means of a primer layer - directly on the roll core, so these rollers are particularly preferably represent distributor rollers, which may be provided with a cooling device. If a hard-elastic intermediate layer is provided between the roll core and cover, then these rolls can be used particularly preferably as transfer rolls, which can work against transfer rolls which are related to elastic material, but optionally also as transfer rolls.

Furthermore, the invention relates to a printing press with a roller according to the invention. The roller according to the invention can work against at least one counter-roller with a cover made of an elastic, polymeric material of lower hardness. The elastic, polymeric material of the counter roll can in this case be a fluoroelastomer or the reference of the counter roll may contain such a fluoroelastomer. The friction or transfer roller according to the invention can be part of an inking unit. The roll according to the invention can also be used in dry offset.

In the figure, a printing machine with inventively designed friction and transfer rollers is shown schematically.

The printing machine 10 (in particular offset printing machine) has a dampening unit 11 and a printing unit 12 for printing on a printing medium, such as a paper web. The dampening unit 11 has a fountain solution reservoir 14, from which by means of a fountain roller 15 a fountain solution such as auxiliaries added water is conveyed. The conveyed dampening solution is metered by a metering roller 16 operating against the fountain roller. The dampening solution film produced thereby is subsequently transferred to at least one dampening applicator roll 17 and then transferred from the dampening unit 11 to the plate cylinder 18 (also called printing form cylinder) of the dampening unit 12. Instead of the plate cylinder can of course be used in a corresponding manner, a printing plate, which may optionally directly print the respective object. On the plate cylinder 18 is further applied by the rollers 26 of an inking unit 25, a printing ink or generally a Verdruckmittel. The Verdruckmittel is in this case conveyed from a reservoir 27 by means of a ductor roller 28 or other conveyor and transmitted by means of a usually elastomer-coated lifting roller 29 on a distributor roller 30. The squeegee roller 29 is hereby reciprocated between the ductor roller 28 and the distributor roller 30 in an oscillating manner. A part or all of the distributor rollers may in this case be designed according to the invention, for example according to the aforementioned embodiments. The distributor rollers 30 may be partially designed as non-oscillating transfer rollers. A part or all of the rollers 26 may be coated soft elastic. Between the following ink rollers 26 and the distributor rollers 30, a homogeneous Verdruckmittelfilm desired thickness is generated in each case, which is transmitted to the plate cylinder 18.

It will be appreciated that, alternatively, the inking unit 25 may also be embodied as a film inking unit in which the ductor is doctored off and has no direct contact with a non-elastomeric coated film roll running at machine speed.

Generally, the rolls of the invention formed as distributor rolls become traversing, i. operated oscillating in the roll longitudinal direction and work against transfer rollers, which are preferably coated elastically. The distributor rollers according to the invention can each be provided with a cooling device. The distributor rollers are usually permanently but interchangeably mounted in the printing unit, since the distributor rollers have a very long service life. The transfer rollers used according to the invention in this case exert no traversing movement.

In the usual way, the printed image formed on the plate cylinder 18, which is produced by rather hydrophilic and rather hydrophobic areas on the plate cylinder, then transferred via the blanket cylinder 20 to the print carrier 13, wherein the print carrier 13 between the blanket cylinder 20 and a counter-pressure cylinder 21 performed becomes.

In general, in the case of an inking unit of a printing press, a Verdruckmittelreservoir is provided, is conveyed from which Verdruckmittel means of a suitable device and fed to the inking unit by means of a lifting roller or other transfer device. Over the rollers of the inking unit, the elastically coated transfer rollers, inventive hard transfer rollers and distributor rollers, the Verdruckmittel then a printing plate cylinder or other printing plate transferred, which has to produce a corresponding image hydrophilic and hydrophobic surface areas, and then usually from the printing plate cylinder via a blanket cylinder to an object to be printed such. B. transferred to a paper layer. The friction and transfer rollers according to the invention are thus preferably arranged between the lifting roller and the printing form cylinder or the printing plate. The friction or transfer roller according to the invention can in this case operate against one or more rollers provided with an elastic cover. Optionally, dyeing and dampening solution can also be performed in combination, so that the plate cylinder 18 as intended, a colorant dampening solution emulsion is supplied. However, the roller according to the invention can also be used in particular in waterless offset, preferably in offset machines without dampening unit.

According to the exemplary embodiment, the rolls according to the invention can have a coating with a coating of ≥ 15 Shore D. These rollers can work against elastically coated transfer rollers whose surface cover, for example, a hardness of 20 to 60 Shore A, for example, about 30 Shore A can have. The cover may consist of a base polymer in the form of a highly crosslinked, non-elastic (non-entropy-elastic) fluoropolymer, in addition to fillers and other conventional components, or such polymer at more than 50% by weight based on the polymer content or total weight of the polymer Cover included. The roll or the roll cover may have a surface roughness of ≤ 3 μm Rz. The fluorinated polymer may have 10 to 20 crosslinking sites with respect to the polymer backbone having a carbon number corresponding to 100 C4-C8 monomers and may be, for example, a fluorinated polyurethane resin, polyester resin, epoxy resin, acrylate resin, polycarbonate or polyether resin. The fluoropolymer may contain as copolymers vinylidene fluoride and hydropentafluoropropylene monomer units. Alternatively, the reference fluoropolymer may also be a fluorothermoplastic be and include ECTFE, FEP, PVDF, and / or THV. As a further alternative, the fluorinated polymer may also be a fluoropolymer varnish. The fluorinated polymer may each be perfluorinated, without being limited thereto. The filler content of the cover may be about 20% by weight, based on the total weight of the cover material. The layer thickness of the cover can be about 40 microns. Between the cover and the roll core may be provided an intermediate layer of hard rubber whose hardness is less than or equal to the hardness of the fluoropolymeric cover.

The above-described cover or other cover according to the present invention may be a fluoropolymer cover having a scratch hardness of 6B according to ISO 15184: 1998 (E) or harder, for example having a scratch hardness of ≥ 4B, ≥ 2B or ≥ B, preferably harder and has a scratch hardness of ≥ F or ≥ H, more preferably a scratch hardness of ≥ 2H or ≥ 4H.

The scratch test can be performed at room temperature (22 degrees Celsius) and at a relative humidity of 50%. To determine the scratch hardness specified here, an Elcometer 501 pencil hardness tester can be used. The scratch hardness can be determined using Faber-Castell 9000 Design Set (pencil hardness 6B-6H) pens. These conditions may apply to any information relating to the invention. The stated pencil hardness (scratch hardness) thus corresponds in each case to the hardest pencil, in which a corresponding scribe mark is barely recognizable, for example by visual perception by visual inspection or by manual palpation.

In the context of the invention, as determined by the experimental investigations on the covers according to the invention, it has been found that a barely visible scratch has a depth of approximately 1 μm, whereby such a score can no longer be touched manually is. Cracks or grooves with a depth of less than 0.5 microns, which can represent a plastic deformation of the cover material are no longer measurable by the used in the investigations of the invention measuring instruments and no longer noticeable in the glancing angle to the human eye. The measurement of the scribe depth was carried out in the context of the invention by molding the crack by means of suitable impression materials such as "Mikrosil" -Abdruckmassen, which were then measured under a surface stylus for the stylus method according to DIN ISO 4288.1989 in terms of profile height, z. Example by means of a device of the type "waveline" Hommelwerke. Alternatively, to determine the profile height, a strip triangulation measuring device for structural analysis of surfaces such as the ODSCAD device from GF Messtechnik (see values of the GFM evaluation of Tables 1 and 2) or a white light interferometer can be used. On the basis of these investigations, it can thus be stated that in the case of the scratch hardness of the roll cover, the scores (no longer perceptible) generated by the scoring test have a depth of ≦ 0.5 μm, if present, which is the case for coatings with one Surface roughness Rz of ≤ 2 μm applies.

The scratch hardnesses in the context of the invention relate to surfaces with a roughness Rz of 2-3 μm, in particular about 2 μm or smaller, unless stated otherwise. If the roughness of a cover to be examined is greater than about 2-3 microns, it should before the performance of the scoring trial by suitable means, such as by polishing, to said roughness Rz of 2-3 microns, in particular about 2 microns be smoothed to provide comparable results.

The visible scratches produced in each case typically have a width of 200-300 μm or more, in particular at deeper scratches.

The measured values were determined in each case on a plate / sheet provided with the cover material with a thickness of the cover of approximately 40 μ. The values apply, however, if the scribing tests are carried out on a roller coated with the cover.

Generally, in the context of the invention, the cover material can be applied to the roll core, for example, from the liquid phase, wherein the roll core can be prepared with a bonding agent. Optionally, a hard intermediate layer may also be applied to the core, optionally also using an adhesion promoter, in which case a primer and then the cover material is applied by coating the liquid phase as a coating to the hard intermediate layer, so that the cover has a layer thickness in may have the order of 15 to 50 microns, unless otherwise specified.

The test sheets for the scribe tests are sandblasted sheet metal with a Rz smaller 15μm, which were subsequently coated with 15 microns of a suitable liquid phase adhesion promoter in the spray application and then after half-hour intermediate drying at 40 ° C with the function coating (cover) of fluorocarbon resin likewise spray-coated, this time in two stages, with about 25 μm, after two hours of drying at room temperature was then crosslinked at 140 ° C for 4 hours. The resulting roughness of the reference surface is primarily a result of the spray and application parameters. The dryer the aerosol is applied, the rougher the coating. The test is carried out after 24 hours storage in normal climate.

Embodiment 1 here refers to a first roll cover according to the invention with a surface roughness of the undamaged surface of 1.4 μm (Rz). As a substrate serves a steel sheet. pencil hardness Steel 1) GFM evaluation depth [μm] 4B invisible not measured 3B Point of support of the pencil minimally visible Measurement can not be evaluated 2 B visible scratch, not palpable ~1.3 B visible scratch, palpable ~ 1.8 HB visible scratch, palpable ~ 2.5 F visible scratch, palpable (top coat scratched) ~ 2.6 H Visible scratch, palpable (punctiform destruction of the surface down to the metal) ~ 2.25 2H visible scratch, palpable (1mm long destruction of the surface except for the metal) ~ 4.6 3H 12mm long destruction of the surface down to the primer layer, point-like destruction of the surface down to the metal ~ 20.0 4H 14mm long destruction of the surface down to the primer layer, point-like destruction of the surface down to the metal ~16.0 1) fluorohydrocarbon resin (roll cover material) coated

Exemplary embodiment 2 shows a scratch hardness determination Wolff-Willborn to another embodiment. The surface roughness of the undamaged surface was 5 μm (RZ). Substrate is a steel sheet. The thickness of the examined reference layer is 40 μm. pencil hardness Steel 1) GFM evaluation depth [μm] 2 B invisible not measured B invisible not measured HB invisible Measurement can not be evaluated F punctiform destruction of the topcoat to the metal ~ 40 H punctiform destruction of the topcoat to the metal ~ 40 2H punctiform destruction of the topcoat to the metal ~ 35 3H punctiform destruction (1.33mm) of the topcoat except for the metal and visible scratch, not palpable ~ 45 4H punctiform destruction (1.14mm) of the topcoat except for the metal and visible scratch, not palpable ~ 49 5H Destruction (1.15 and 2.11mm) of the topcoat to the metal ~ 36 6H Destruction (2.83 and 3.08mm) of the topcoat except for the metal ~ 34 1) fluorohydrocarbon resin (roll cover material) coated
Rz value of the undamaged surface: 4.95 μm

Claims (15)

1. Contact or transfer roller for printing machines, in particular offset printing machines, wherein said roller has a rigid core and a cover from a polymer material applied and permanently fixed to the core, wherein said cover is applied by means of a coupling agent layer or directly to the core or to a hard-elastic intermediate layer having a hardness of ≥ 10 Shore D, wherein the cover consists for more than 50% by weight of fluoridated polymers and wherein the cover has a hardness of ≥15 Shore D and/or a scratch hardness according to ISO 15184 of 6B or higher, characterized in that the fluoridated polymer is a thermosetting or energy-elastic material.
2. Roller according to claim 1, characterized in that the surface energy of the surface of the roller cover amounts to ≤ 25 mN/m.
3. Roller according to one of the claims 1 or 2, characterized in that the hardness of the cover is within a range of 25 to 80 Shore D.
4. Roller according to one of the claims 1 to 3, characterized in that the hardness of the hard-elastic intermediate layer is within a range of 20 to 50 Shore D.
5. Roller according to one of the claims 1 to 5, characterized in that the roller has a surface roughness ≤ 15 µm Rz.
6. Roller according to one of the claims 1 to 5, characterized in that the fluoridated polymer comprises more than 10 to 20 cross-linking points in relation to the polymer basic structure having a carbon number corresponding to 100 C4-C8 monomers.
7. Roller according to one of the claims 1 to 6, characterized in that

   (i) the fluoridated polymer comprises at least one or more from the group of fluoridated polyurethane resin, polyester resin, epoxy resin, acrylate resin, polycarbonate and polyether resin respectively and/or

   (ii) the fluoridated polymer is a polymeric, non-elastic fluorosilicone or contains polymeric, non-elastic flourosilicone units.
8. Roller according to one of the claims 1 to 7, characterized in that the polymer is a highly cross-linked non-elastic fluorinated polymer or a fluorinated thermoplastic material or a fluorinated polymer lacquer.
9. Roller according to claim 8, characterized in that the fluorinated polymer is a copolymer, inclusive terpolymer or tetrapolymer, which contains monomer units of vinylidene fluoride, hexafluoropropylene, chlortrifluoroethylene, hydropentafluoropropylene, tetrafluoroethylene, perfluorovinyl ether, perfluoromethylvinyl ether and/or ethylene; and/or that the fluorinated thermoplastic material comprises at least one or several of the polymers of ECTFE, ETFE, FEP, PFA, PVDF, PTFE and/or THV.
10. Roller according to one of the claims 1 to 9, characterized in that the fluoridated polymer has a fluorine content such that ≥ 50 atomic percent of the hydrogen atoms of the polymer are substituted for fluorine atoms.
11. Roller according to one of the claims 1 to 10, characterized in that filler content of the cover amounts to ≤ 75% by weight in relation to the total weight of the cover material.
12. Roller according to one of the claims 1 to 11, characterized in that the layer thickness of the cover amounts to ≤ 200 µm.
13. Roller according to one of the claims 1 to 12, characterized in that the hardness of the intermediate layer is smaller than/equal to the hardness of the fluoridated polymer cover and/or that the elasticity of the intermediate layer is larger than/equal to the elasticity of the fluoridated polymer cover.
14. Roller according to one of the claims 1 to 13, characterized in that the hard-elastic intermediate layer consists of hard rubber.
15. Printing machine comprising at least one roller according to one of the claims 1 to 14.

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