DE102011018343A1 - Substrate contacting, structured surface with a substrate and at least one layer - Google Patents

Abstract

A structured surface contacting printing material according to the invention (e.g. a transport cylinder elevator) with a substrate (e.g. made of nickel) and at least one layer, the layer (7) comprising at least two layers (7a, 7b) and one of the two layers contains particles (8), is characterized in that both layers (7a, 7b) contain particles (8) (e.g. from cobalt aluminates) that the particles (8) of both layers have an average size of less than about 2 micrometers, preferably about 0.3 micrometers, and that the substrate (4) has a structure (5) with an RZ value between about 20 micrometers and about 40 micrometers. The double layer (7, 7a, 7b) according to the invention gives the surface (1) a high level of wear resistance. Advantageously, cracks in the surface (1) can be avoided and a homogeneous double layer (7, 7a, 7b) can be produced.

Description

The present invention relates to a printed material contacting, structured surface having a substrate and at least one layer having the features of the preamble of claim 1.

It is known, substrates such. B. to promote paper sheets with transport cylinders by printing presses. In order to prevent fresh ink from settling on the cylinders and contaminating them, the cylinders are provided with interchangeable elevators (or "jackets") which are microstructured and anti-adhesive coated. The microstructure reduces the contact surface between the elevator and substrate and improves due to the roughness of the guide of the substrate. An anti-adhesive seal reduces the paint acceptance property of the elevator.

The DE 101 58 433 B4 discloses a coating with a sol-gel primer layer and a particle layer. The particles have an average particle size of 2 to 150 nanometers.

The JP 09-175703 A discloses a transport roller with a coating on a roughened substrate. The coating comprises a layer of hard, granular material and a low surface energy, thermally sprayed, porous composite layer disposed thereabove.

The DE 10 2005 060 734 A1 discloses an anti-adhesion layer of crosslinked nanoparticles and a method of preparation. The non-stick layer is produced by the known sol-gel process, hard particles being added to the layer formers for a particularly high level of wear resistance. The particles may be diamond powder or cubic boron nitride with a particle size of 0.1 to 5 microns. The release layer comprises a composite material having two interpenetrating three-dimensional networks: an inorganic network and a polyorganosiloxane network. However, a system of several superimposed layers is not described.

The DE 10 2005 037 338 A1 discloses a non-stick coating and a method of making the same. The following layers are arranged on a substrate: a pre-primer, a main primer with inclusions, an intermediate cover layer comprising silicone compounds and a main top layer, also containing silicone compounds. The substrate is pretreated, for. B. by sandblasting. The deposits are mixed in as particles in the starting material and produce a surface structure that is to favor the non-stick effect. The main primer layer may consist of several layers. The deposits may consist of ceramic, metal, silicate or glass and have a particle size of 5 to 50 micrometers. However, it is not described that more than one layer of the main primer layer has inclusions. Quantitative data on the roughness of the substrate are not made.

It is also already known to use colored coatings. The JP 2000-016611 A discloses a roller with a metal core and a rubber jacket. Below the rubber sheath a colored layer is arranged. When the rubber jacket wears out, the colored layer appears locally and shows the wear locally due to the color change.

Printers are constantly demanding improved print quality and increased productivity. The cylinder lifts should therefore be particularly wear-resistant than the prior art and retain their color-repelling functionality over many print jobs, so that a time-consuming cleaning or even a more time-consuming replacement is required only rarely. Since the elevators usually have several layers, there is consequently the requirement that each individual layer and also the composite of the layers have the required service life.

Against this background, it is an object of the present invention to provide a comparison with the prior art improved printing contacting, structured surface with a substrate and at least one layer having sufficient wear resistance and anti-adhesiveness even for increased demands on print quality and productivity.

These objects are achieved by a printed material contacting, structured surface having a substrate and at least one layer having the features of claim 1. Advantageous developments of the invention will become apparent from the accompanying dependent claims and from the description and the accompanying drawings.

A printed material contacting, structured surface having a substrate and at least one layer, wherein the layer comprises at least two layers and one of the two layers contains particles, characterized in that both layers contain particles that the particles of both layers has a mean size of less than about 2 microns and that the substrate has a structure with an R _{z of} between about 20 microns and about 40 microns.

The substrate or the carrier has a (coarse) structuring. As a rough structure is here refers to a structure with the novel R _Z value. Preferred in view of the above according to the invention R _Z value a generated, structured by galvanic shaping, and therefore rough substrate is provided. The substrate is preferably nickel, and preferably has a thickness between about 200 microns and about 400 microns. Instead of nickel, aluminum or another metal or a ceramic may also be provided as the material for the substrate. Alternatively, the patterning can be generated by thermal spraying, laser, (sand) blasting, engraving or embossing. The structuring is preferably provided with a chromium layer, ie chromed. The chromium layer preferably has a thickness between about 2 microns and about 15 microns.

On the structuring according to the invention a layer is provided, which consists of two layers. The two layers are advantageously applied in separate steps and in succession. This separate application of the two layers leads to an overall more stable and wear-resistant layer, since cracking can be prevented. Cracks can z. B. arise when too thick layers are generated in a job step. Stored particles in the individual layers also contribute to the reduction of internal stresses and therefore again to avoid cracking.

The upper, first layer preferably has a thickness between about 0.5 microns and about 8 microns. The lower, second layer also preferably has a thickness between about 0.5 microns and about 8 microns. The lower layer also serves advantageously as an adhesion promoter between the coarse-structured substrate and the upper layer. The particles projecting superficially from the lower layer after their production advantageously improve the adhesion between the two layers. This can be attributed to mechanical effects (clamping of both layers).

Both layers preferably have a sol-gel material, i. H. They are preferably produced in a sol-gel process. As a sol-gel z. B. the product "H5163" from FEW Chemicals in Bitterfeld-Wolfen be used.

According to the invention both layers contain embedded particles, d. H. a sol-gel / particle bilayer is provided. The particles are preferably hard particles and especially pigments which increase wear resistance. Both layers preferably have substantially equal particles (i.e., same material and same average size). The particles preferably have a mean size between about 0.1 microns and about 0.5 microns, especially about 0.3 microns.

The particles, because of their average size of less than about 2 microns (more preferably less than about 1 micron), provide for fine patterning of the surface in addition to the above-mentioned coarse patterning. The fine structuring is in the range below 2 microns. An advantageous lower limit for the fine structuring has been found to be 0.1 micrometer. The superficial protruding from the upper layer and the (fine) structure-generating particles improve the wear resistance of the surface crucial. The contact points between surface and substrate are reduced to the small and hard particles. In between, there is essentially no contact with the printing material. Therefore, the sol-gel layer is less stressed and remains longer. The pigments also enhance the sol-gel network and therefore contribute to its improved wear resistance.

The proportion of the particles in the sol-gel is preferably between about 20% and about 60%, in particular about 50% (proportion of pigments based on the solids content of the sol-gel).

It has surprisingly been found that the use of the particles in the lower layer causes possible cracks in the chromium layer to close better and be covered by the sol-gel. In turn, this makes it possible to produce a homogeneous particle layer with a minimum thickness of about 0.5 microns. The particles act as anchors for the sol-gel and due to the high number of particles the sol-gel finds correspondingly many anchor points. As a result, it adheres firmly to the underlying layer or layer and forms a layer or layer of a minimum thickness.

Preferably, both layers are thinner in the region of mountains of the structure of the substrate than in the region of valleys of the structure of the substrate and each have a thickness of more than 0.5 micrometers in the region of the peaks. It is advantageous that cracks in the area of the structure peaks are also covered by the particles and in this way serve as anchors for a double layer with a given minimum thickness. In this way, it can be prevented that the mountains are coated with a sol-gel layer to a small thickness and that cracks in the chromium layer continue after curing of the sol-gel layer in the sol-gel layer and reduce their wear resistance ,

Preference is given to using pigments based on cobalt aluminates or iron-cobalt. Such particles (cobalt aluminates) have a blue Color and color the surface therefore blue (iron cobalt: black). The stain can be used to indicate progressive wear by exposing a deeper, particulate, and therefore unstained layer locally. Moreover, the dyeing can advantageously help to distinguish a cylinder elevator according to the invention when replacing another elevator and thereby avoid confusion. Alternatively, other particles can be used, for. As iron-cobalt, SiC, SiN or SiCN.

The invention will be described below with reference to the accompanying drawings with reference to at least one preferred embodiment.

The drawings show:

1 a schematic sectional view of a preferred embodiment of a surface according to the invention; and

2 a schematic detail view of two layers of a layer of the surface.

1 shows a schematic sectional view of a preferred embodiment of a surface according to the invention 1 , The surface is considered a flexible cylinder lift 2 trained and on a transport cylinder 3 a printing material processing machine, z. B. a sheet-processing lithographic offset printing machine, recorded, z. B. spanned as a so-called jacket.

The area 1 includes a substrate 4 made of nickel. The substrate has a structuring produced by galvanic molding 5 (Mountains and valleys). The nickel substrate is chromed, ie with a chromium layer 6 Mistake.

On the chrome layer 6 is a sol-gel layer 7 intended. The sol-gel layer has a lower layer 7a and an upper layer 7b from sol-gel on. In both layers are particles 8th (please refer 2 ) embedded in cobalt aluminate.

In 1 it can be seen that the two layers 7a and 7b the rough structure 5 to level. On the mountains of the structure 5 are the two layers 7a and 7b about thinner than in the valleys of the structure 5 ,

2 shows a schematic detail view of two layers 7a and 7b a layer 7 the area 1 , In both layers are particles 8th stored. By particles 8a on the surface of the lower layer 7a There is a mechanical clamping of the two layers and thereby to a firm adhesion of the upper layer to the lower layer.

particle 8b on the surface of the upper layer 7b cause the coarse structure 5 (please refer 1 ) a fine structure 9 (Mountains and valleys) is superimposed. This preserves the area 1 a variety of substrates to be printed, hard contact points 10 ,

In 2 is also shown that by the incorporation of the particles 8th into the sol-gel of the bilayer 7 possible cracks 11 in the chrome layer 6 can be easily covered.

LIST OF REFERENCE NUMBERS

1

area

2

cylinder lift

3

transport cylinder

4

substratum

5

(Coarse) Structuring

6

chromium layer

7

Sol-gel layer

7a

lower position

7b

upper layer

8th

particle

8a

particle

8b

particle

9

(Fine) structure

10

contact points

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10158433 B4 [0003]
• JP 09-175703 A [0004]
• DE 102005060734 A1 [0005]
• DE 102005037338 A1 [0006]
• JP 2000-016611 A [0007]

Claims (10)

Substrate-contacting, structured surface with a substrate and at least one layer, wherein the layer ( 7 ) at least two layers ( 7a . 7b ) and one of the two layers of particles ( 8th ), characterized in that - both layers ( 7a . 7b ) Particles ( 8th ), that the particles ( 8th ) of both layers have an average size of less than about 2 micrometers, and - that the substrate ( 4 ) a structure ( 5 ) having an R _z value between about 20 microns and about 40 microns. Substrate contacting surface according to claim 1, characterized in that - the first layer ( 7a ) has a thickness between about 0.5 microns and about 8 microns, and that the second layer ( 7b ) has a thickness between about 0.5 microns and about 8 microns. Substrate contacting surface according to claim 1, characterized in that both layers ( 7a . 7b ) have a sol-gel material. Substrate contacting surface according to claim 1, characterized in that - both layers ( 7a . 7b ) substantially identical particles ( 8th ), and - that the particles ( 8th ) have an average size of less than about 1 micrometer. Substrate contacting surface according to claim 1, characterized in that - both layers ( 7a . 7b ) substantially identical particles ( 8th ), and - that the particles ( 8th ) have a mean size between about 0.1 microns and about 0.5 microns, more preferably about 0.3 microns. Substrate contacting surface according to claim 1, characterized in that both layers ( 7a . 7b ) in the area of mountains of the structure ( 5 ) of the substrate ( 4 ) thinner than in the area of valleys of the structure ( 4 ) of the substrate ( 5 ) and in the region of the mountains each have a thickness of more than 0.5 micrometers. Substrate contacting surface according to claim 1, characterized in that the particles ( 8th ) Are pigments based on cobalt aluminates or that the particles ( 8th ) Are pigments based on iron-cobalt. Substrate contacting surface according to claim 6 or 7, characterized in that the particles ( 8th ) have a blue color and color the area blue or that the particles ( 8th ) have a black color and color the area black. Substrate contacting surface according to claim 1, characterized in that the substrate ( 4 ) is a chromed, galvanically formed nickel sheet. Substrate processing machine, characterized by a cylinder ( 3 ) with a substrate contacting surface ( 1 ) according to one of claims 1 to 8.

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