Method for producing a plastic doctor blade and plastic doctor blade

Abstract

Method for producing a plastic doctor blade (100), comprising the steps: - Providing a first material web (30) with a length (l 30 ) in longitudinal direction and one in comparison to the length (l 30 ) smaller width (b 30 ) made of a first plastic material, - Laminating the first material web (30) with at least one second material web (32) made of a second plastic material different from the first plastic material, so that a laminating web (34) is formed, the length in longitudinal extension and width of which corresponds to the length (l 30 ) and width (b 30 ) of the first material web (30), - cutting the laminating web (34) along its longitudinal extent along at least one point of the width (b 34 ) of the laminating web (34) attached cutting edge (36), so that several doctor blade webs (40) are formed, the length (l 40) corresponds in longitudinal extension to the length of the lamination web (34), and - manufacturing the plastic doctor blade (100) from one of the doctor blade webs (40), wherein a first longitudinal side (50) of the doctor blade web (40) forms a scraping edge (54) of the plastic doctor blade (100) and an opposite longitudinal side (58) of the doctor blade web (40) forms a fastening section (60) of the plastic doctor blade (100), via which the plastic doctor blade (100) can be fastened in a doctor blade holder, wherein the at least one second material web (32) has smaller dimensions than the first material web (30) and the first material web (30) is only partially laminated with the at least one second material web (32), characterized in that the first plastic material of the first material web (30) comprises at least one of the following materials: BOPET (biaxially oriented polyethylene terephthalate), POM (polyoxymethylene), PA6 or PA6.6 (polyamide; number corresponds to the number of carbon atoms in the monomer) and / or the second plastic material of the second material web (32) comprises at least one of the following materials: PEEK (polyetheretherketone), FTP (fluorothermoplastics), FE (fluoroelastomers), PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), UHMW-PE (ultra-high molecular weight polyethylene), glass fiber, carbon fiber.

Description

[0001] The present invention relates to a method for producing a plastic doctor blade according to the preamble of claim 1.

[0002] Furthermore, the invention relates to a plastic doctor blade produced by the described method. In particular, the invention relates to a plastic doctor blade for use in a machine for wiping excess liquid (e.g., paint or ink; adhesive; pigments (e.g., nickel, cadmium, etc.) in liquid or viscous form) from a surface (e.g., a printing roller of a printing press; a surface of a material web to be bonded in a bonding machine; a surface of a metal foil in a machine for producing battery electrodes). The plastic doctor blade comprises the features of the preamble of claim 12.

[0003] A generic method for producing a plastic doctor blade and a plastic doctor blade itself are known, for example, from JP S61-176953 A. Further prior art on the subject of plastic doctor blades and / or their production is represented, for example, by DE 202 16 016 U1, DE 60 004 489 T2, and DE 20 2015 004 314 U1.

[0004] Cutting the doctor blade webs to the required length to produce a plastic doctor blade with a required width is preferably done by the customer, who purchases the doctor blades, for example, in rolled up form from the manufacturer. In this way, the customer can adapt the width of the doctor blade to the desired purpose or the conditions in a machine in which the doctor blade is to be used. As a rule, the plastic doctor blades are fastened to a fastening section formed on the long side of the plastic doctor blade opposite the wiping edge, in a doctor blade holder that is part of a printing machine, a paper manufacturing machine, an gluing machine, a machine for producing battery electrodes or another machine. The plastic doctor blade is preferably pressed with its long side, which forms a wiping edge and is possibly chamfered, against the surface of a cylindrical roller of the machine, which e.g.made of steel, chrome or ceramic. The roller can be designed as an anilox roller or anilox roller of a printing machine, in which case the doctor blade serves to wipe off excess ink or paint from the roller surface. To apply adhesive or another more or less liquid fluid to a material web, the plastic doctor blade can alternatively be pressed with its wiper edge onto the surface of the material web in order to wipe off the excess liquid from the material web. The liquid can be an adhesive in a gluing machine or a liquid with pigments (e.g. nickel or chromium) in a machine for producing battery electrodes.

[0005] In the prior art, it is common practice to laminate several plastic films over their entire surface to create squeegee tracks that are thicker than the individual plastic films. These squeegee tracks have the same thickness across their entire surface, corresponding to the sum of the thicknesses of the individual plastic films. The greater thickness of the squeegee tracks is necessary to ensure that the plastic squeegees made from the squeegee tracks have sufficient stability in the area of ​​their wiping edge. On the one hand, the wiping edge must not be too hard to avoid damaging the surface it scrapes over, but on the other hand, it must be sufficiently abrasion-resistant to prevent rapid wear of the squeegee edge and to achieve an acceptable service life for the plastic squeegee.

[0006] Every effort is made to ensure that the plastic materials used for the known plastic doctor blades meet the requirements placed on the plastic doctor blade in terms of stability, torsional rigidity, and abrasion resistance. Plastic materials that meet these requirements particularly well include PEEK (polyetheretherketone), FTP (fluorothermoplastics), FE (fluoroelastomers), PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), UHMW-PE (ultra-high molecular weight polyethylene), glass fiber, or carbon fiber. However, these materials are many times more expensive than the conventional materials commonly used for plastic doctor blades, such as BOPET (biaxially oriented polyethylene terephthalate), POM (polyoxymethylene), PA6, or PA6.6 (polyamide; the number corresponds to the number of carbon atoms in the monomer). If, for example, one of the expensive materials is used for the second plastic material of the second material web, this increases the price of the doctor blade webs.of the resulting plastic doctor blade, since in the state of the art the first material web is completely laminated over its entire surface area with the second material web.

[0007] Based on the described prior art, the present invention is based on the object of proposing a plastic doctor blade which, on the one hand, particularly well meets the requirements with regard to stability, torsional rigidity and abrasion resistance and, on the other hand, can also be manufactured at the lowest possible prices.

[0008] To achieve this object, a method for producing a plastic doctor blade with the features of claim 1 is proposed. In particular, based on the method for producing a plastic doctor blade of the type mentioned at the outset, it is proposed that the first plastic material of the first material web comprises at least one of the following materials: BOPET (biaxially oriented polyethylene terephthalate), POM (polyoxymethylene), PA6 or PA6.6 (polyamide; number corresponds to the number of carbon atoms in the monomer) and / or the second plastic material of the second material web comprises at least one of the following materials: PEEK (polyetheretherketone), FTP (fluorothermoplastics), FE (fluoroelastomers), PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), UHMW-PE (ultra-high molecular weight polyethylene), glass fiber, carbon fiber.

[0009] Laminating is the joining of several layers of the same or different materials (e.g. films). The laminating of the material webs can be carried out by wet lamination (joining using wet adhesive), dry lamination (joining using dry adhesive) or thermal lamination (joining without adhesive using heat and / or pressure). Usually, but not exclusively, a preferably self-adhesive second material web is cold-bonded to the first material web under pressure. Laminating creates a physical bond between the second material web and the first material web. This creates an undetachable bond. In the context of the invention, the term “laminating” includes both classic lamination and lamination.

[0010] The method according to the invention can be used to produce plastic doctor blades that are laminated with the second material web in the area of ​​greatest wear, e.g., in the area of ​​their wiping edge, to achieve greater resistance there. This results in high abrasion resistance while simultaneously reducing costs, since the second material web is only laminated to a portion of the first material web. Of course, it would be conceivable to laminate the first material web with more than just one second material web. In particular, it would be conceivable to laminate two or more second material webs one above the other onto the first material web.

[0011] In the method according to the invention, the sequence of the individual method steps is not predetermined by the list in claim 1. In particular, it would be possible to cut the material webs along their longitudinal extension along at least one cut edge before lamination. After lamination of the cut material webs, the doctor blade paths would then be created.

[0012] The squeegee tracks can be chamfered along their first long side, or the plastic squeegee along its wiping edge. Chamfering a long side of the squeegee tracks usually only occurs after the (possibly already cut) material webs have been laminated. Chamfering can be performed by grinding, milling, cutting, and / or any other method of material removal. During chamfering, the speed and feed rate should be adjusted to the respective material properties of the first and / or second plastic material of the material webs.

[0013] The production of the plastic squeegee from the squeegee webs preferably involves cutting sections of the squeegee webs to the desired length, preferably at the customer's site. Each cut section forms a plastic squeegee. The length of the cut section corresponds to the width of the finished plastic squeegee, and the width of a squeegee web corresponds to the height of the plastic squeegee.

[0014] The first plastic material of the first material web comprises at least one of the following materials: BOPET (biaxially oriented polyethylene terephthalate), POM (polyoxymethylene), PA6, or PA6.6 (polyamide; the number corresponds to the number of carbon atoms in the monomer). Alternatively or additionally, the second plastic material of the second material web comprises at least one of the following materials: PEEK (polyetheretherketone), FTP (fluorothermoplastics), FE (fluoroelastomers), PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), UHMW-PE (ultra-high molecular weight polyethylene), glass fiber, or carbon fiber. Of course, any other suitable materials can also be used as the first or second plastic material.It would also be conceivable to use a material for the second plastic material which is not currently used for plastic doctor blades and / or which will only be discovered or developed in the future, but is obviously also suitable for use in the plastic doctor blades according to the invention.

[0015] According to an advantageous development of the invention, it is proposed that the first material web is laminated with the at least one second material web made of the second plastic material only in the region of the at least one cut edge to be subsequently introduced along the longitudinal extent of the first material web and only over part of the width of the first material web. Preferably, the first material web is laminated with the second material web in the region of the cut edge of the squeegee web, which later forms the wiper edge of the finished plastic squeegee. The first material web is therefore not laminated on the long side opposite the at least one laminated cut edge. In the finished plastic squeegee, this unlaminated long side preferably forms the fastening section by means of which the squeegee is fastened in the squeegee holder of the machine in which the squeegee is used.

[0016] According to a preferred embodiment of the invention, it is proposed that the first material web is laminated with the at least one second material web made of the second plastic material on both sides of the at least one cut edge to be subsequently introduced along the longitudinal extent of the first material web only over part of the width of the first material web. If the laminating web is therefore cut, for example, along three longitudinal cuts into a total of four doctor blade webs, it would be sufficient to laminate the laminating web on both sides of the first and third cut edges with a correspondingly dimensioned second material web. No lamination would be necessary along the second cut edge. The first and third longitudinal cuts would then run in the longitudinal direction of the laminating web, preferably approximately centrally through the second material web.The laminated longitudinal side of adjacent squeegee strips would then be on opposite longitudinal sides, e.g., from the left in the first squeegee strip, on the right longitudinal side, in the second squeegee strip, on the left longitudinal side, in the third squeegee strip, and on the left longitudinal side, in the fourth squeegee strip. In this context, it is proposed that the laminated strip be cut with an odd number of longitudinal cuts into an even number of squeegee strips.

[0017] Cutting the lamination web into the squeegee webs can be done in a variety of ways. For example, it would be conceivable to cut the lamination web using a knife (e.g., a longitudinal knife or a rotary knife). Alternatively, other cutting methods can be used, such as water jets, laser beams, or air jets.

[0018] Advantageously, the second plastic material has greater abrasion resistance, in particular greater hardness, than the first plastic material. The following hardness testing methods can be used to determine the hardness: - Barcol hardness test, - Buchholz hardness test, - IRHD hardness test, - Knoop hardness test, - ball indentation hardness test, - Rockwell hardness test, - Shore hardness test, or - Vickers hardness test.

[0019] Which hardness testing method can or should be used depends, among other things, on the characteristics of the material being tested. Significant differences between the test methods include the shape and size of the indenters. Abrasion resistance also depends on the materials involved (the scraper edge and the surface).

[0020] It is further proposed that the second plastic material have a lower coefficient of sliding friction µ than the first plastic material. This applies in particular when the wiper edge slides on steel, chrome or ceramic, from which a machine roller can be made, over whose surface the wiper edge glides to wipe off excess ink or paint. Of course, this can also apply to other surface materials in other machines. During sliding friction, the friction surfaces move relative to one another. Various methods are known from the prior art for calculating the coefficient of friction. Laminating the first material web with such a second material web in the area of ​​the possibly chamfered first long side or the wiper edge thus improves the service life of the plastic doctor blade.At the same time, the more expensive second plastic material is laminated to the first material web only in the area of ​​the wiping edge, but not in the area of ​​the opposite fastening section, so that the plastic squeegee can be manufactured particularly inexpensively despite its longevity.

[0021] The first and second plastic materials of the first and second material webs are preferably different materials. The first material web can primarily meet the requirements for stability and torsional rigidity of the finished plastic doctor blade, while the second material web can primarily meet the requirements for a long service life of the finished plastic doctor blade. Of course, however, it would also be conceivable to use the same materials for the first and second plastic materials of the first and second material webs. Cost savings would then result from the fact that double the material thickness is only required in the area of ​​the wiping edge, where the plastic doctor blade can wear during use, and only a single material thickness is provided in the area of ​​the fastening section.

[0022] According to another advantageous development of the invention, it is proposed that the chamfer is introduced along the first longitudinal side of the squeegee webs in such a way that the second plastic web protrudes beyond the first plastic web in the region of the chamfer or is flush with it. This has the advantage that the wiping edge is formed by the more durable and robust second material web, resulting in particularly high abrasion resistance of the plastic squeegee. If the wiping edge becomes worn or blunted after prolonged use, an increasingly large portion of the second plastic web in the region of the wiping edge will be flush with the first plastic web. In this case, the first longitudinal side of the plastic squeegee can be chamfered again, resulting in a tapered wiping edge that is formed solely by the second material web.

[0023] The chamfer has an angle of between 10° and 60°, preferably an angle of 13°, 22°, 30°, or 45°, relative to a reference plane running perpendicular to the surface extension of the squeegee tracks. Depending on the application of the plastic squeegee, e.g., depending on the fluid used and / or the material of the surface over which the wiping edge wipes to remove excess fluid, the wiping edge can be optimized by chamfering at any desired angle, which may also lie outside the above-mentioned preferred range.

[0024] The thicknesses of the first and second material webs can be chosen arbitrarily, but the material webs are preferably plastic films. The thicknesses of the two material webs can be the same or different. According to a further preferred embodiment of the invention, it is proposed that the first material web and the second material web each have a thickness between 200 µm and 3,500 µm, preferably a thickness in the range of 500 µm. In the area of ​​the wiping edge, the plastic squeegee then has a thickness that corresponds to the sum of the thicknesses of the individual material webs. On the opposite fastening section, the finished plastic squeegee has a thickness that corresponds only to the thickness of the first material web.

[0025] The lengths of the first and second material webs along their longitudinal extents can be chosen arbitrarily, but the material webs are preferably rolled up plastic films with a length of several tens of meters. According to a preferred embodiment of the invention, it is proposed that the first material web and the second material web each have a length between 100 m and 1,000 m, preferably a length in the range from 200 m to 550 m. Other lengths of the two material webs are of course also conceivable. This allows for particularly efficient and cost-effective production of the doctor blade webs. The laminating web and the doctor blade webs are preferably rolled up. The doctor blade webs are preferably delivered to the customer in rolls. This allows for particularly easy handling of the doctor blade webs during transport and at the customer's site.The customer can cut a section of the desired length from the squeegee strips and thus receive a plastic squeegee of the desired width.

[0026] The widths of the squeegee tracks can be chosen as desired. In particular, the widths of the squeegee tracks are selected according to the customer's wishes and requirements regarding the height of their plastic squeegee, since the width of the squeegee tracks corresponds to the height of the finished plastic squeegee. According to a preferred embodiment of the invention, it is proposed that the squeegee tracks each have a width between 15 mm and 150 mm, preferably between 20 mm and 70 mm. Other squeegee track widths are of course also conceivable. The width of the squeegee tracks corresponds to the distance between the cutting edges with which the lamination track is cut into the squeegee tracks along its longitudinal extent.

[0027] Preferably, the doctor blades cut from the lamination web are all of the same width. The width of the individual doctor blades corresponds to the width of the lamination web divided by (the number of cut edges + 1). However, it would also be conceivable for the individual doctor blades to have different widths. In this way, doctor blades for different applications and / or for different customers can be produced from a single lamination web.

[0028] According to another advantageous development of the invention, it is proposed that the first material web is laminated with a plurality of second material webs distributed across the width of the first material web and arranged at a distance from one another, which second material webs run parallel to one another in their longitudinal extent and parallel to the longitudinal extent of the first material web. Advantageously, the first material web is only laminated with the at least one second material web in those areas which form the first longitudinal side or the wiper edge in the finished plastic doctor blade. It is further proposed that the at least one second material web has a smaller width than the width of the doctor blade webs. In particular, it is proposed that the at least one second material web has a width between 5 mm and 20 mm, preferably between 8 mm and 12 mm, very particularly preferably 10 mm.Of course, the width of the second material web can also be any other value, as long as the width of the second material web is less than the width of the first material web or the doctor blade webs. Multiple second material webs laminated side by side or one above the other onto the first material web can also have different widths.

[0029] As already mentioned, the invention further proposes that, to produce the plastic doctor blade, sections of the doctor blade webs are cut to length from the doctor blade tracks. Each cut section forms a plastic doctor blade, and the length of the cut section corresponds to the width of the finished plastic doctor blade, while the width of a doctor blade track corresponds to the height of the plastic doctor blade. Cutting can be performed by the manufacturer of the doctor blade webs or by the customer, i.e., by the operator of the machines that use the plastic doctor blade.

[0030] The present invention also includes a plastic doctor blade produced by the inventive method for producing a plastic doctor blade described here.

[0031] The invention further comprises a plastic doctor blade with the features of claim 12. In particular, starting from the plastic doctor blade of the type mentioned at the outset, it is proposed that the first plastic material of the first material web comprises at least one of the following materials: BOPET (biaxially oriented polyethylene terephthalate), POM (polyoxymethylene), PA6 or PA6.6 (polyamide; number corresponds to the number of carbon atoms in the monomer) and that the second plastic material of the second material web comprises at least one of the following materials: PEEK (polyetheretherketone), FE (fluoroelastomers), PVDF (polyvinylidene fluoride), UHMW-PE (ultra-high molecular weight polyethylene), glass fiber, carbon fiber.

[0032] Further features and advantages of the present invention are explained in more detail below with reference to the figures. The individual features shown in the figures and / or described below may each be essential to the invention on their own, even if this is not expressly stated. Furthermore, the individual features shown in the figures and / or described below may be combined with one another in any desired manner, even if this is not expressly stated. They show: Fig. 1 a flow diagram of the method according to the invention for producing a plastic doctor blade and, as part thereof, of the method according to the invention for producing a doctor blade web; Fig. 2 a device for implementing the method according to the invention for producing a doctor blade web; Fig. 3 a doctor blade track according to the invention; Fig. 4 a plastic doctor blade according to the invention according to a preferred embodiment in a perspective view; Fig. 5 the plastic squeegee from Fig. 4 in a cross-section; and Fig. 6 a plastic doctor blade according to the invention according to another preferred embodiment in a cross section.

[0033] Fig. 1 shows a flow diagram of the method according to the invention for producing a plastic doctor blade 100. The method begins in a functional block 10. In a subsequent functional block 12, a first material web 30 with a longitudinal extent and a width that is smaller than the longitudinal extent and made of a first plastic material is provided.

[0034] In the example, the first material web 30 has a length l 30 from about 200 m to 550 m and a width b 30 of about 200 mm. Other lengths l 30 and widths b 30are conceivable. In the example, the first material web 30 is rolled up. However, it can also be stacked or provided in another way (e.g., in superimposed layers).

[0035] In the example, the first material web 30 comprises at least one of the following materials: BOPET (biaxially oriented polyethylene terephthalate), POM (polyoxymethylene), PA6, or PA6.6 (polyamide; the number corresponds to the number of carbon atoms in the monomer). However, the use of other suitable materials is also conceivable.

[0036] In a subsequent functional block 14, the first material web 30 is laminated with at least one second material web 32 made of a second plastic material different from the first plastic material, so that a laminating web 34 is formed, the length and width of which correspond to the length l 30 and width b 30essentially corresponds to the first material web 30. Minor deviations in the length and width of the laminated web 34 compared to the first material web 30 may arise during the laminating process (e.g., by applying pressure and heat). The laminating process can be performed in any desired manner. It is conceivable that the first material web 30 is also laminated with several second material webs 32 running one above the other.

[0037] In the example, the first material web 30 is laminated with two second material webs 32, which extend over the width b 30 the first material web 30 are arranged next to each other and spaced apart from each other. Depending on the width b 30 the first material web 30 and the desired width b 40 the squeegee track 40 or the desired height h 100However, in the finished plastic doctor blade 100, second material webs 32 running more or less side by side can also be used to laminate the first material web 30.

[0038] In the example, the second material web has a length that corresponds to the length l 30 of the first material web 30. In the example, the second material web 32 has a width b 32 of about 20 mm. Other lengths and widths b 32 However, other configurations are conceivable. In particular, the first material web 30 and the second material webs 32, or the second material webs 32, can have different lengths and / or widths from one another. In the example, the second material webs 32 are rolled up. However, they can also be stacked or provided in other ways (e.g., in superimposed layers).

[0039] In the example, the second material web 32 comprises at least one of the following materials: PEEK (polyetheretherketone), FTP (fluorothermoplastics), FE (fluoroelastomers), PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), UHMW-PE (ultra-high molecular weight polyethylene), glass fiber, carbon fiber. However, the use of other suitable materials is also conceivable. In particular, the use of previously unknown or developed materials that exhibit particularly high abrasion resistance is also conceivable.

[0040] In this example, the thicknesses of the first and second material webs 30, 32 are each approximately 500 µm. However, other thicknesses are also conceivable. Furthermore, the thicknesses of the first and second material webs 30, 32 can differ from one another. Due to their low thicknesses, the first and second material webs 30, 32 can also be referred to as plastic films.

[0041] In a subsequent functional block 16, the laminating web 34 is cut along its longitudinal extent along at least one cutting edge 36 applied at at least one point of the width of the laminating web 34, so that several doctor blade webs 40 are formed, the length l 40 the length of the lamination strip 34 and its width b 40 - if all squeegee tracks 40 have the same width b 40 have - the width b 34 the laminating strip 34 divided by the (number n 36 of the cutting edges 36 + 1) corresponds to (b 40 = b 34 / (n 36 +1)).

[0042] In the example, three cut edges 36 are introduced into the laminating web 40, resulting in four doctor blade webs 40. The first and third cut edges 36 run along the longitudinal extent approximately centrally through the laminated second material web 32 and divide it into two second partial material webs 32.1 and 32.2, each of which has half the width of the second material web 32, i.e., in the example, a width of 10 mm each. Of course, it would also be conceivable to laminate the two partial material webs 32.1, 32.2 each as separate second material webs 32 onto the first material web 30. Other widths of the partial material webs 32.1, 32.2 are also possible, depending on the width b. 32 the second material web 32 are conceivable.

[0043] The cutting of the lamination web 34 along the cutting edges 36 can be carried out in any manner, for example by means of a knife, a laser beam, a water jet or an air jet. In the example, the exemplary Fig. 3 is rolled up. However, it can also be stacked or stored in another way (e.g., in several layers stacked one above the other). The squeegee web 40 can be delivered in this stored form to a customer for further processing, in particular for the production of the plastic squeegee 100 from the squeegee web 40.

[0044] If the first material web 30 has only a width b from the beginning 30 which corresponds to the width b 40 the squeegee track 40 or the height h 100the finished plastic doctor blade 100, step 16 can be omitted. In this case, the first material web 30 is only laminated with a strip of the second material web 32. For this reason, the functional block 16 is shown only in dashed lines.

[0045] In a functional block 18, a chamfer 52 (cf. Fig. 4 and Fig. 5) which forms a scraping edge 54 of the finished plastic doctor blade 100 (cf. Fig. 5). In the example, the bevel 52 has an angle α of between 10° and 60°, preferably an angle of 13°, 22°, 30°, or 45°, with respect to a reference plane 56 running perpendicular to the surface extension of the doctor blade webs 100. Other angles α of the bevel 52 are also conceivable. A longitudinal side 58 opposite the bevel 52 or the wiping edge 54 forms a fastening section 60 of the plastic doctor blade 100, via which the plastic doctor blade 100 can be fastened in a doctor blade holder (not shown) of a machine in which the doctor blade 100 is used. The bevel 52 is preferably introduced onto the longitudinal side 50 of the doctor blade web 40 in such a way that the second material web 32 protrudes beyond the first material web 30 towards the longitudinal side 50 (cf. Fig. 5) and the stripping edge 54 is formed solely by the second material web 32.

[0046] The chamfering of the doctor blade track 40 along its first longitudinal side 50 can also be omitted (cf. Fig. 6). Therefore, the functional block 18 is shown only in dashed lines. In this case, the wiping edge 54, with which the doctor blade 100 wipes over the surface 56, 57, is formed by both material webs 30, 32. The wiping edge 54 can be flat or - as in Fig. 6 - be curved. A flat wiping edge 54 results when the plastic doctor blade 100 wipes along a flat surface 56. A curved wiping edge 54 results when the plastic doctor blade 100 wipes along a curved surface, e.g., a roller 57. Plastic doctor blades 100 with such a wiping edge 54 are used, for example, as wash-up doctor blades in offset printing. One difference from the chamfered doctor blades 100 is the wear of the wiping edge 54. Due to the height h 100 the doctor blade 100 constant thickness of the plastic doctor blade 100 in the area of ​​the wiping edge 54, it will wear constantly and evenly over time.

[0047] Another difference in Fig. 6 is that the first material web 30 has a recess 62 along the entire width b 100 of the doctor blade 100, in which the second material web 32 runs. The second material web 32 is laminated or glued into the recess 62. The second material web 32 is thus flush with the outside of the first material web 30 (cf. right outside of the doctor blade 100 in Fig. 6). The recess 62 can be introduced into the first material web 30 in any desired manner, e.g., by cutting. The introduction of the recess 62 can be carried out during the production of the lamination web 34 (see Fig. 1) or during the production of the doctor blade track 40.

[0048] This completes the inventive method for producing a doctor blade web 40 and can be terminated (in a functional block 22). However, the inventive method for producing a plastic doctor blade 100 requires a further step in functional block 20. For this reason, functional block 20 is shown only in dashed lines.

[0049] In the functional block 20, the plastic doctor blade 100 is manufactured from the doctor blade web 40. This can be done, for example, by cutting a section of a desired length l 100 from the doctor blade track 40. A corresponding cutting edge is provided in Fig. 3 is designated by the reference numeral 42. The first longitudinal side 50 of the doctor blade 40 forms the wiping edge 54 of the finished plastic doctor blade 100 and the opposite longitudinal side 58 of the doctor blade 40 forms the fastening section 60 of the finished plastic doctor blade 100. The length l 100 of the cut section of the squeegee track 40 (cf. Fig. 3) corresponds to the width b 100 the finished plastic squeegee 100 (cf. Fig. 4). Accordingly, the width b 40 the squeegee track 40 (cf. Fig. 3) the height h 100 the finished plastic squeegee 100 (cf. Fig. 4). The cutting of the plastic squeegee 100 from the squeegee web 40 is preferably carried out at the customer's site according to their wishes or according to the specifications and requirements for the planned use of the plastic squeegee 100 in the customer's machine.

[0050] In the functional block 22, the method according to the invention for producing the plastic doctor blade 100 can then be terminated.

[0051] It is conceivable that in the method according to the invention the individual steps 12 to 20 are carried out in a different order than in Fig. 1. For example, it would be conceivable that the first material web 30 is first cut longitudinally along the cutting edges 36 (step 16) and only then is it laminated with the at least one second material web 32 (step 14) to obtain the doctor blade webs 40.

[0052] From the figures it can be clearly seen that the at least one second material web 32 has smaller dimensions, in particular a smaller width b 32 , than the first material web 30 and that the first material web 30 is only partially laminated with the at least one second material web 32, in particular in the region of the long side 50 of the doctor blade web 40 or the stripping edge 54 of the finished plastic doctor blade 100. This has the consequence that the plastic doctor blade 100 is only in the region of the stripping edge 54 (in Fig. 4 and Fig. 5 in the lower part of the finished doctor blade 100) has a greater thickness s, which results from the sum of the thicknesses of the individual material webs 30, 32. At an opposite area of ​​the fastening section 60 (in Fig. 4 and Fig. 5 in the upper part of the finished squeegee), the plastic squeegee 100 has only a smaller thickness, which corresponds to the thickness of the first material web 30.

Claims

[1] A method for producing a plastic doctor blade (100), comprising the steps of: - Providing a first material web (30) with a length (l 30 ) in longitudinal direction and one in comparison to the length (l 30 ) smaller width (b 30 ) made of a first plastic material, - Laminating the first material web (30) with at least one second material web (32) made of a second plastic material different from the first plastic material, so that a laminating web (34) is formed, the length in longitudinal extension and width of which corresponds to the length (l 30 ) and width (b 30 ) of the first material web (30), - cutting the laminating web (34) along its longitudinal extent along at least one point of the width (b 34 ) of the laminating web (34) attached cutting edge (36), so that several doctor blade webs (40) are formed, the length (l 40) corresponds in longitudinal extension to the length of the lamination web (34), and - manufacturing the plastic doctor blade (100) from one of the doctor blade webs (40), wherein a first longitudinal side (50) of the doctor blade web (40) forms a scraping edge (54) of the plastic doctor blade (100) and an opposite longitudinal side (58) of the doctor blade web (40) forms a fastening section (60) of the plastic doctor blade (100), via which the plastic doctor blade (100) can be fastened in a doctor blade holder, wherein the at least one second material web (32) has smaller dimensions than the first material web (30) and the first material web (30) is only partially laminated with the at least one second material web (32), characterized by , that the first plastic material of the first material web (30) comprises at least one of the following materials: BOPET (biaxially oriented polyethylene terephthalate), POM (polyoxymethylene), PA6 or PA6.6 (polyamide; number corresponds to the number of carbon atoms in the monomer) and / or the second plastic material of the second material web (32) comprises at least one of the following materials: PEEK (polyetheretherketone), FTP (fluorothermoplastics), FE (fluoroelastomers), PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), UHMW-PE (ultra-high molecular weight polyethylene), glass fiber, carbon fiber. [2] Method according to claim 1, characterized by that a chamfer (52) is introduced along the first longitudinal side (50) of the doctor blade track (40), which forms the scraping edge (54) of the plastic doctor blade (100). [3] Method according to claim 2, characterized by , that the chamfer (52) is introduced along the first longitudinal side (50) of the doctor blade web (40) in such a way that the second plastic web (32) protrudes beyond the first plastic web (30) in the region of the chamfer (52) and / or the bevel (52) has an angle (α) of between 10° and 60°, preferably an angle (α) of 13°, 22°, 30° or 45°, with respect to a reference plane (56) running perpendicular to the surface extension of the doctor blade track (40). [4] Method according to one of the preceding claims 2, characterized by , that the first material web (30) is only in the area of ​​the at least one cutting edge (36) to be subsequently introduced along the longitudinal extent of the first material web (30) only over a part of the width (b 30 ) the first material web (30) is laminated with the at least one second material web (32) made of the second plastic material and / or the first material web (30) on both sides of the at least one cutting edge (36) to be subsequently introduced along the longitudinal extent of the first material web (30) only over a part of the width (b 30 ) of the first material web (30) is laminated with the at least one second material web (32) made of the second plastic material. [5] Method according to one of the preceding claims, characterized by , that the second plastic material of the second material web (32) has a higher abrasion resistance, in particular a greater hardness, than the first plastic material of the first material web (30) and / or the second plastic material of the second material web (32) has a lower coefficient of sliding friction, in particular on steel, chromium or ceramic, than the first plastic material of the first material web (30). [6] Method according to one of the preceding claims, characterized by , that the first material web (30) and the second material web (32) each have a thickness between 200 µm and 4,000 µm, preferably a thickness in the range of 500 µm, and / or the first material web (30) and the second material web (32) each have a length (l 30 ) between 100 m and 1,000 m, preferably a length (l 30 ) in the range of 200 m to 550 m. [7] Method according to one of the preceding claims, characterized by that the doctor blade tracks (40) each have a width (b 40 ) between 15 mm and 150 mm, preferably between 20 mm and 70 mm. [8] Method according to one of the preceding claims, characterized by that the first material web (30) is provided with several over the width (b 30) of the first material web (30) and arranged at a distance from one another, which second material webs (32) run parallel to one another in their longitudinal extent and parallel to the longitudinal extent of the first material web (30). [9] Method according to one of the preceding claims, characterized by that the first material web (30) is laminated with the at least one second material web (32) only in the areas which form the scraping edge (54) in the finished plastic doctor blade (100). [10] Method according to one of the preceding claims, characterized by , that the at least one second material web (32) has a smaller width (b 32 ) than the width (b 40 ) of the doctor blade track (40) and that the at least one second material web (32) in the finished plastic doctor blade (100) has a width (b 32) between 5 mm and 20 mm, preferably between 8 mm and 12 mm, most preferably 10 mm. [11] Method according to one of the preceding claims, characterized by that, in order to manufacture the plastic doctor blade (100), sections of the doctor blade web (40) are cut to length from the doctor blade web (40), wherein each cut section forms a plastic doctor blade (100) and has a length (l 100 ) of the cut section of a width (b 100 ) of the plastic squeegee (100) and a width (b 40 ) of the doctor blade track (40) of a height (h 100 ) of the plastic squeegee (100). [12] Plastic doctor blade (100) for use in a machine for wiping excess liquid from a surface, wherein the plastic doctor blade (100) is a laminate of several laminated plastic films (30, 32), a first longitudinal side (50) forms a wiping edge (54) with which the plastic doctor blade (100) slides over the surface to wipe off the excess liquid, and comprises a fastening section (60) formed on the longitudinal side (58) opposite the wiping edge (54), which is designed to fasten the plastic doctor blade (100) to a squeegee holder of the machine, wherein the plastic doctor blade (100) comprises a first film (30) made of a first plastic material, which is laminated only in the region of the wiping edge (54) with at least one second film (32) made of a second plastic material different from the first plastic material, so that the wiping edge (54) is formed by the first plastic film (30) and the at least one second plastic film (32) laminated thereon, and that the fastening section (60) is formed only by the first plastic film (30), characterized by , that the first plastic material of the first material web (30) comprises at least one of the following materials: BOPET (biaxially oriented polyethylene terephthalate), POM (polyoxymethylene), PA6 or PA6.6 (polyamide; number corresponds to the number of carbon atoms in the monomer) and the second plastic material of the second material web (32) comprises at least one of the following materials: PEEK (polyetheretherketone), FE (fluoroelastomers), PVDF (polyvinylidene fluoride), UHMW-PE (ultra-high molecular weight polyethylene), glass fiber, carbon fiber. [13] Plastic doctor blade (100) according to claim 12, characterized by that the plastic doctor blade (100) is chamfered along the first longitudinal side (50) in the region of the scraping edge (54).

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