Mould for producing plastics products, and method for reworking such a mould

Abstract

The invention relates to a mould for producing plastics products, the mould comprising a metal mould body (120) and a hard material coating (220) which at least partially covers the metal mould body. The hard material coating has a surface (222) on which the plastics product is moulded during the production of the plastics product. The surface of the hard material coating comprises a structured zone having a structure (320) which is introduced into the hard material coating and is transferred into the plastics product during moulding. The invention also relates to a method for reworking a mould for producing plastics products, which mould comprises a metal mould body (120) and a hard material coating (220) which at least partially covers the metal mould body and has a surface (222) on which the plastics product is moulded during the production of the plastics product, wherein the surface of the hard material coating comprises a structured zone (Z) having a structure (320) which is introduced into the hard material coating and is transferred into the plastics product during moulding, wherein the method comprises: removing the hard material coating (220); applying a further hard material coating to the metal mould body, which coating at least partially covers the metal mould body; and structuring the further hard material coating, whereby a further structured zone (Z) having a further structure (320') is formed which is transferred into the plastics product during moulding, wherein the structure and the further structure are identical or different.

Description

[0001] TOOL FOR THE MANUFACTURE OF PLASTIC PRODUCTS AND METHOD FOR REWORKING SUCH A TOOL

[0002] The invention relates to a tool for manufacturing plastic products and a method for reworking such a tool.

[0003] Tool-based processes are used to manufacture plastic products, all of which share the common feature that a surface of the plastic product is molded onto a surface of the tool (often also referred to as the contour surface). This maps the shape of the tool's contour surface onto a surface of the plastic product.

[0004] Common methods for manufacturing plastic products include injection molding, blow molding, and thermoforming. Accordingly, injection molds, blow molds, and thermoforming tools are used to produce these plastic products.

[0005] Furthermore, it is already known to create microstructures on the surface of plastic products during the manufacturing process. For this purpose, the contour surface of the tool used is provided with a microstructure forming a surface topography, which is then transferred to the surface of the plastic product during the manufacturing process, following the contours. It has been shown that very fine markings can be produced on the plastic product in this way.

[0006] To create microstructures on the tool surface, it must be structured (textured). This involves directly embedding the surface topography into the steel surface of the tool. However, renewing and / or subsequently modifying the microstructure on the tool due to wear is only possible through complex processes involving weld overlay and subsequent cavity correction.

[0007] EP 3 566 799 Bl describes the application of a PVD or CVD coating to a sintered tool body, covering a code marking. The coating is sufficiently thin to ensure that the code marking remains legible.

[0008] US 11,900,497 Bl describes a plastic product that is digitally watermarked during manufacturing.

[0009] One of the problems underlying the invention can be seen as creating a tool for the production of plastic products which offers the possibility of generating microstructures on the surfaces of plastic products, whereby lower costs should be incurred in the event of wear or necessary changes to the microstructure of the tool. In particular, welding as well as correction of the geometry of a molding surface of the tool should be avoided.

[0010] The problem addressed by the invention is solved by the features of the independent claims. Exemplary embodiments and further developments are the subject of the dependent claims.

[0011] Accordingly, a tool for manufacturing plastic products comprises a metallic tool body and a hard coating that covers at least parts of the metallic tool body. The hard coating has a surface against which the plastic product is molded during its manufacture. The surface of the hard coating includes a structured zone, which has a structure incorporated into the hard coating that is transferred to the plastic product during the molding process.

[0012] The hard coating eliminates the need to incorporate the structure into the surface of the metallic tool body. Instead, the tool's contour surface is formed by the surface of the hard coating, and the structure of the textured zone is incorporated into the hard coating.

[0013] Thus, the material properties of the hard coating are used to generate the surface topography (structure) of the tool's contour surface. Furthermore, the hard coating allows for simple and cost-effective modification of the structure (and therefore also of the inverse structure or marking created on the plastic product) without requiring extensive tool repair or the construction of a new tool. Instead, the existing hard coating simply needs to be removed, another hard coating applied to the metallic tool body, and this new hard coating re-structured. This allows a worn structure to be replaced with an identical one and / or a structure to be replaced with a modified one.

[0014] For example, the hard coating can comprise a PVD (Physical Vapor Deposition) layer and / or a CVD (Chemical Vapor Deposition) layer, or consist of one or more such layers. PVD and CVD layers can be deposited on the surface of the metallic tool body in very thin layers without significantly altering the dimensions of the metallic tool body (and thus also the dimensions of the plastic product to be manufactured).

[0015] For example, the hard coating can comprise one or more of the following layers: a nitride layer, in particular a TiN layer, AlCrN layer, CrN layer or TiAlN layer; a carbide layer, nitrocarbide layer; a DLC (diamond-like carbon) layer; or a ta-C (tetrahedral amorphous carbon) layer. These layers possess the hardness required for the application and can be finely structured topographically, e.g., by means of a laser (laser texturing).

[0016] In particular, the structure can be a code, such as a digital watermark. In this case, this code is transferred to the plastic product. This makes it possible to link coded information, or information made available through code reading, to the plastic product itself. To obtain this information, the code, which is imprinted on the surface of the plastic product in a contour-conforming manner through the structuring, can be read, for example, optically.

[0017] The code can encode one or more pieces of information that identify usage and / or recycling information for the plastic product, in particular the plastic product itself, the manufacturer of the plastic product, the manufacturing method of the plastic product, the manufacturing material(s) of the plastic product, and / or the contents of a plastic product container. Usage information for the plastic product can, for example, relate to logistics data, goods inspection data, and / or data relating to the sale of the plastic product in retail. Recycling information can include all data that can be used for sorting and / or further processing the plastic product or parts thereof produced by shredding the plastic product within the framework of the circular economy.For example, recycling information may include details on the manufacture of the plastic product, the manufacturing method of the plastic product, the manufacturing material or materials of the plastic product, as well as, for example, details on the contents of a plastic product container that may be important for recycling (for example, because the contents are absorbed by the material of the plastic product).

[0018] Furthermore, the code can identify the plastic product itself, for example in the form of a unique article number that identifies the plastic product.

[0019] Furthermore, the structure can encode an address for an entry about the plastic product in a database. In this way, virtually any data and data sets can be linked to the plastic product and made available by reading the code.

[0020] Another possibility is that the structure constitutes an aesthetic and / or a functional feature of the plastic product. An aesthetic feature is visible to the human eye on the plastic product. For example, it could be a hologram or a special optical surface effect, such as a shark-skin effect or an ultra-matte surface. An example of a functional feature on the plastic product is a Fresnel lens.

[0021] Furthermore, it is also possible that an aesthetic and / or a functional feature is overlaid with a code.

[0022] The hard coating can have a thickness between 1 pm and 50 pm, in particular 2 pm and 20 pm or 4 pm and 10 pm. The thickness must be at least as great as the structure depth to allow the desired structure depth.

[0023] For example, the structure can have a structural depth that is a maximum of 90% of the thickness of the hard coating. This means that the hard coating is preferably not cut through during the structuring process, since the structural depth is less than the thickness of the hard coating. This allows, for example, surface roughness created by laser processing in the hard coating to be transferred to the surface of the plastic product in the structured areas and thus be optically detectable there.

[0024] For example, the structure can have a structural depth between 0.5 pm and 6 pm, in particular 1 pm and 4 pm or 1 pm and 2 pm. These structural depths can be sufficient to achieve the desired properties in the plastic product, e.g., the readability of a code formed by the structure (microstructure).

[0025] For certain applications, the total base area of ​​depressions within the textured zone may be equal to or less than 10% of the area of ​​the textured zone. This means that the texturing within the textured zone may constitute a relatively small proportion of that zone.

[0026] Digital watermarks, in particular, can exhibit this property.

[0027] The structured zone can comprise a cell array consisting of a multitude of first cells and second cells of the same shape, where the surface roughness in first cells is at least twice the surface roughness in second cells. As will be explained in more detail below, this method can be used, for example, to generate digital codes on the plastic product.

[0028] The surface of the hard coating can have several structured zones with identical structures. This means that the structuring present in a structured zone can be distributed across various locations, possibly over a large portion of the surface, or even across the entire surface of the hard coating. Accordingly, the structure molded onto the plastic product can be created multiple times, over a large portion of the surface of the plastic product, or across the entire surface of the plastic product.

[0029] The present disclosure can be applied to a wide variety of manufacturing processes for plastic products. In particular, the tool can be an injection mold, a blow mold, or a thermoforming tool.

[0030] Furthermore, a method for reworking a tool for manufacturing plastic products is described, comprising a metallic tool body and a hard coating that covers at least parts of the metallic tool body. The hard coating has a surface against which the plastic product is molded during its manufacture. The surface of the hard coating includes a structured zone with a structure incorporated into the hard coating that is transferred to the plastic product during molding. The method includes removing the hard coating. Subsequently, another hard coating is applied to the metallic tool body, covering at least parts of it.A further structure is incorporated into the additional hard coating, creating another structured zone with a further structure that is transferred to the plastic product during molding. The structure and the subsequent structure may be identical or different.

[0031] Tool reworking allows the tool to be renewed, for example, when its structure becomes worn. Furthermore, reworking can also be carried out as a modification of the tool, by altering the structure encompassed by the tool. This is advantageous, for instance, when the plastic products to be manufactured are to be identical in construction but with different structures (e.g., codes). A specific application of this is, for example, a plastic container that is to be filled with a different filler, where the respective filler should be identifiable as coded information on the plastic product, for example, for recycling purposes.

[0032] The removal of the hard coating can be achieved, for example, chemically. Etching processes can be used, which selectively attack or remove the coating but not the material of the metallic tool body (usually tool steel). In particular, the hard coating is destroyed during removal, meaning it cannot be lifted off while preserving its shape or removed without damage.

[0033] Structuring the hard material coating, as well as reworking the tool for further hard material coating, can be achieved, for example, using laser ablation. As described in more detail below, laser ablation (laser texturing) can be used to create fine 3D structures in the hard material coating.

[0034] In particular, the method can be used to rework tools that manufacture recyclable plastic products. In this and other cases, the structure can represent a code, the further structure can represent another code that differs from the first code, and the code and the further code can encode one or more pieces of information that denote usage and / or recycling information for the plastic product.

[0035] Examples and implementation possibilities of the invention are explained in more detail below with reference to the drawings.

[0036] Figure 1 shows a schematic top view of an example of a tool comprising a coated metallic tool body for manufacturing a plastic product. Figure 1 also shows various examples of structured zones.

[0037] Figure 2 shows the coated metallic tool body of the

[0038] Figure 1 in sectional view along line XX in Figure 1. Figure 3A shows in schematic sectional view a section D of Figure 2 before the structuring of the hard material coating.

[0039] Figure 3B shows in schematic sectional view the section D of Figure 3A after the structuring of the hard material coating .

[0040] Figure 4 illustrates in schematic form exemplary processes that can be carried out for the revision of a tool.

[0041] Terms such as "application" or "application" and similar terms (e.g., "applied" or "carried on") are not to be understood in this description as meaning that the applied or carried layers must have direct contact with the surface on which they are applied or carried. Intermediate elements or layers may be present between the "applied" or "carried on" elements or layers and the underlying surface. However, the aforementioned or similar terms in this disclosure may also have the specific meaning that the elements or layers have direct contact with the underlying surface, i.e., that no intermediary elements or layers are present.

[0042] The term "over," used in reference to an element or layer of material formed or applied "over" a surface, can be understood here to mean that the element or layer of material is applied "indirectly onto" the surface, with intermediate elements or layers potentially present between the surface and the element or layer. However, the term "over" can also have the specific meaning that the element or layer of material applied or applied "over" a surface is applied "directly onto," i.e., in direct contact with, the surface in question. The same applies analogously to similar terms such as "overlying," "underlying," "lying beneath," etc.

[0043] Figure 1 shows a schematic representation of a tool 100 for the production of plastic products. The tool 100 has a metallic tool body 120. The tool body 120 of the tool 100 is a component of the tool 100 on which the plastic product to be manufactured is molded. That is, the tool body 120 is, at least in some areas, shaped in such a way that it defines the contour of the plastic product to be manufactured.

[0044] Depending on the type of tool 100, the tool body 120 can have different designs. For example, the tool body 120 can be a mold insert or a mold half of, for example, an injection mold 100. Such mold inserts, also called mold cavities, are incorporated, for example, into the mold plates of injection molds.

[0045] As known in the prior art, in injection molding two opposing mold halves are closed, creating a cavity between them. Plastic is injected into this cavity, where it solidifies to form a molded plastic part (plastic product). The mold halves are then opened, and the molded plastic part (plastic product), which has a contour identical to the cavity surfaces, is removed. Furthermore, the tool 100 can be, for example, a blow molding tool or a thermoforming tool. In blow molding, a preform is heated and inflated in the shaping blow molding tool 100 (or the mold body 120 enclosed by the blow molding tool 100) so that it conforms to the contour surface of the mold body 120. Hollow plastic products (so-called blow-molded plastic parts such as bottles, canisters, etc.) can be produced by blow molding.

[0046] Furthermore, the tool 100 can also be a thermoforming tool. Thermoforming allows the production of plastic products such as plastic films or plastic sheets with wall thicknesses in the millimeter or centimeter range. These tools 100 also include a tool body 120 with a contoured surface on which the plastic product is produced in a contour-forming (i.e., contour-inverted) manner.

[0047] According to the present disclosure, the tool body 120 can be identical to the tool 100. However, it is also possible that the tool body 120 is merely a component of the tool 100, e.g., a mold plate insert in an injection mold.

[0048] As shown in Figure 2, the metallic tool body 120 is at least partially coated with a hard material coating 220. The hard material coating 220 is located in a contour-forming area of ​​the tool body 120 above its surface 122. It can, for example, cover the entire contour surface 122 of the tool body 120 or only a portion of the contour surface 122. According to the usual definition of the term "coating," the hard material coating 220 is produced by a manufacturing process characterized by the application of a firmly adhering layer of a material (here: hard material) that is amorphous immediately before coating to a workpiece.

[0049] The hard coating 220 has a surface 222 on which the plastic product to be manufactured is molded. In other words, the hard coating 220 provides, at least in some areas, a "new" contour surface for the tool body 120, which, as will be described in more detail below, offers additional possibilities for the production of plastic products.

[0050] The hard material coating 220 can comprise or be a PVD layer and / or a CVD layer. Both processes allow for the production of very thin and dimensionally accurate contour-following layers with constant thickness.

[0051] For the 220 hard coating, nitride layers, carbide layers, or nitrocarbide layers are suitable. Nitrid layers can contain, for example, TiN, AlCrN, CrN, and / or TiAlN, or consist of these substances. Furthermore, carbon-based layers such as DLC and / or ta-C layers can also be used. Combinations of these layers or layer materials are also possible.

[0052] Figures 3A and 3B show a section D of figure 2 before and after structuring of the skin material coating 220 .

[0053] The hard coating 220 can have a thickness S, which can be between 1 pm and 50 pm. In particular, S can be between 2 pm and 20 pm or 4 pm and 10 pm. The thickness S of the hard coating 220 is preferably constant, and the layer has a very low surface roughness.

[0054] Figure 3B illustrates a structure 320 that is introduced into the hard coating 220, for example, by machining the hard coating 220. The structure 320 can, for example, comprise a plurality of recesses 322. The recesses 322 can, for example, be point-symmetric, rotationally symmetric, and / or strip-shaped. They can be island-shaped, in particular point-shaped, i.e., one recess 322 is not connected to another recess 322. Furthermore, the recesses 322 can be arranged in a specific pattern, as will be explained in more detail below.

[0055] The surface 122 of the tool body 120 can be smooth, as shown in Figure 3B. However, it is also possible that the surface 122 already has a texture (e.g., VDI3400 or milling grooves, etc.) that is superimposed on the structure 320 of the hard coating 220. In the molding process, both textures (i.e., the texture of the surface 122 and the texture (structure 320) introduced into the hard coating 220) are then imprinted.

[0056] Surface structures that are created by mechanical surface processing such as milling or grinding in a surface located under the hard material coating 220 (e.g. the surface 122 of the tool body 120) and are transferred through the hard material coating 220 into the surface 222 of the same do not constitute structures 320 within the meaning of this disclosure.

[0057] The depressions 322 can be created, for example, by laser ablation using a laser beam 340 directed at the surface 222 of the hard coating 220. This technique is also known as laser texturing.

[0058] The structural depth of the structure 320 (i.e., the depth of the recesses 322) can be, for example, between 0.5 pm and 6 pm, in particular 1 pm and 4 pm or 1 pm and 2 pm. Preferably, the recesses 322 are not through-holes, i.e., the bottom of each recess 322 is located in the hard coating 220 and not in the metallic tool body 120.

[0059] The structure 320 introduced into the surface 222 of the hard coating 220 thus forms a surface topography of the hard coating 220. This surface topography is transferred to the surface of the plastic product as an inverse surface topography during the molding process.

[0060] Figure 1 shows a structured zone Z of the hard coating 220. Within the structured zone Z is the structure 320 incorporated into the hard coating 220.

[0061] Depending on the application, the structured zone Z can be the entire surface of the hard coating 220 (or its entire contour surface) or only a portion thereof. If the structured zone Z is only a portion of the hard coating 220, several structured zones Z can be encompassed by the hard coating 220. In particular, the multiple structured zones Z can each have an identical structure 320. This can occur, for example, if the structure 320 of the structured zone Z represents a code, an aesthetic feature, or a functional feature, and this code, aesthetic feature, or functional feature is to be arranged at several locations on the plastic product, especially distributed across its entire surface.

[0062] According to a first embodiment, the structured zone Z can form a functional feature on the plastic product. For example, the functional feature can be an optical element such as a Fresnel lens. Other functional features (especially optical elements) whose operation is based on a specific surface topography can also be implemented.

[0063] Figure 1 shows a structured zone ZI, which, using a Fresnel lens as an example, illustrates a functional feature that is transferred to the surface of a plastic product by molding the structured zone ZI. The recesses 322 of the structure 320 correspond, for example, to the concentric grooves of the Fresnel lens.

[0064] The bottle shown in Figure 1 is merely an example of a plastic product according to the present disclosure. Besides plastic containers, other plastic products such as films, sheets, and arbitrarily shaped plastic molded parts, etc., can also be manufactured. For example, the plastic product in which one or more optical elements (e.g., Fresnel lenses) are integrated can be a sheet-shaped plastic product.

[0065] Another example according to the disclosure is explained in Figure 1 using the structured zone Z2. In this case, the structure 320 of the structured zone Z2 forms an aesthetic feature on the plastic product. The aesthetic feature can, for example, be a special optical surface property of the plastic product. For example, an anti-reflective or ultra-matte surface can be created. This aesthetic feature is also known as an anti-reflective feature or moth-eye effect.

[0066] Highly anti-reflective surfaces can be created by selectively generating a surface topography with increased roughness in the depressions 322. The increased roughness, compared to the roughness of the surface 222 of the hard coating 220, arises at the bottom of a depression 322, e.g., through laser treatment. In this case, the depression 322 can have any shape and / or constitute any proportion of the base area of ​​the structured zone Z2. In particular, a large part or the entire structured zone Z2 can be designed as a depression 322, thus creating a flat, ultra-matte surface on the plastic product.

[0067] Further examples of structuring are explained using the structured zones Z3_l and Z3_2. The structured zones Z3_l and Z3_2 each represent a coded area, i.e., an area containing a code (a structured zone containing a code is generally denoted by the reference sign Z3 in Figure 1). The code corresponds to structure 320 within the structured zone Z3_l or Z3_2 (or generally Z3).

[0068] As already mentioned, this code can be molded at several locations on the surface of the plastic product, and it is also possible for the code to be distributed across the entire surface of the plastic product. The code can be, for example, a barcode or a QR code. In this case, the pattern of such a code is generated in the form of indentations 322 within the structured zone Z.

[0069] For example, a code for the structured zone Z3_l can be implemented as follows: The structured zone Z3_l can be divided into an array of fields F (cells). For example, the fields F can be arranged in a checkerboard pattern within the structured zone Z3_l. Each field F in the structured zone Z3_l can be configured to represent digital information. In this way, the structured zone Z3_l can carry a digital code.

[0070] For example, the digital information of a field F can be encoded such that the value 1 is assigned to a field F containing a depression 322, while the value 0 is assigned to a field F that does not contain a depression 322. There are many other possibilities, such as encoding the values ​​0 and 1 using different shapes and / or depths and / or numbers of depressions 322 within the fields F.

[0071] The size of a field F can, for example, be between 100 pm and 500 pm in one or both lateral dimensions D. The depression ( en) 322 of the structured zone Z3_l can be, for example, equal to or less than 40 pm, 30 pm, 25 pm or 20 pm.

[0072] In particular, it is possible that the total base area of ​​depressions 322 within a structured zone Z (e.g., structured zone Z3_l) represents 10% or less than 10% of the area of ​​structured zone Z. This ensures that the structure (e.g., the code) causes only a minimal disturbance to the surface of the plastic product. Therefore, the code does not affect the surface of the plastic product, either visually or haptically.

[0073] Codes that are invisible to the human eye on a product are also known as digital watermarks. The code or structure 320 can represent a digital watermark.

[0074] The readability of the code can, for example, be based on an increased roughness created at the bottom of a depression 322 during structuring (especially laser processing). This roughness reduces the reflectivity of the corresponding surface on the plastic product by a factor of 1, 5, 2, or more. A code scanner detects the change in reflectivity on the surface of a plastic product within a surface zone corresponding to the structured zone Z3_l and decodes the code based on the measured reflectivity profile.

[0075] According to the present disclosure, a readable character string is also referred to as a code. That is, a structure 320 contained in a structured zone Z3_2 can, for example, represent or comprise a readable character string (e.g., consisting of digits, letters, etc.) which was introduced into the surface 222 of the hard coating 220, for example, by laser ablation (laser engraving, laser texturing) according to Figure 3B.

[0076] One possible application of structured zones Z containing a code is, for example, to distribute this code across the entire surface of the plastic product. A barcode or QR code invisible to the human eye (i.e., a barcode or QR code implemented as a digital watermark) allows, for instance, the code to be scanned at a checkout when the plastic product is sold, without having to search for it on the product itself.

[0077] Another application is using the code to encode usage and / or recycling information for the plastic product. Usage information allows for the monitoring and control of packaging design, logistics processes, goods inspection, and / or retail sales. Recycling information enables improved recycling and thus a more efficient circular economy. In waste sorting facilities, high-resolution cameras can capture the code. Based on the information read, the facility can separate waste into appropriate material streams more effectively than before. If the structured zones Z3_l are distributed over a large part or the entire surface of the hard coating 220, so that the code is applied to a large part or the entire surface of the plastic product, even shredded pieces of the plastic product can be separated.

[0078] For example, the code can encode information that identifies the manufacturer of the plastic product, the manufacturing method of the plastic product, the manufacturing material(s) of the plastic product, and / or the contents of the plastic product if it is designed as a container. The code can also include a unique international identification number for the product, such as EAN (European Article Number) or GTIN (Global Trade Item Number).

[0079] Another possibility is that the structure is 320

[0080] (i.e., the code) encodes the address of an entry for the plastic product in a database. The aforementioned information can then be made available by reading the database address using the extracted code.

[0081] For the aforementioned applications and others, the use of a hard coating 220 in the tool 100 enables simplified reworking of the tool 100 or the tool body 120 when the structure 320 needs to be renewed. This can occur, for example, when the structure 320 needs to be renewed due to wear. Another application is when the structured zone Z needs to be marked with a changed code (see, for example, the structured zones Z3_1, Z3_2). A desired code change can have many different causes, such as a change of manufacturer, a change in the material(s) of the plastic product, or, for example, the filler that is to be filled into a plastic product container.

[0082] Figure 4 illustrates a method for reworking a tool 100 for manufacturing plastic products. The tool 100 is reworked as previously described. It is manufactured by providing a tool body 120 at S1, which is then coated with the hard material coating 220 at S2.

[0083] At S3, the structure (microstructure) 320 is introduced into the coating 220. Subsequently, at S4, plastic products 420 are molded using tool 100 and removed from tool 100 at S5.

[0084] During the revision of tool 100, the following changes are made to S6:

[0085] The hard coating 220 is removed. The removal of the hard coating 220 can be carried out, for example, chemically (e.g., by etching). By removing the hard coating 220 (stripping), the surface 122 of the tool body 120 is exposed.

[0086] Subsequently, at S7, a further hard coating 220' is applied over the metallic tool body 120.

[0087] The further hard coating 220' is structured at S8, thereby forming another structured zone Z with a further structure 320'.

[0088] The additional hard coating 220' and the additional structure 320' can be produced in the same manner as described for hard coating 220 and structure 320, respectively. Therefore, to avoid repetition, reference is made to the description above.

[0089] The additional hard coating 220' can be designed differently or identically to the hard coating 220.

[0090] The subsequent structure 320' can be implemented differently or identically to structure 320. For example, if code needs to be changed, different structures 320 and 320' are used.

[0091] For S9 and S10, analogous processes are carried out as for S4 and S5 respectively to produce another plastic product 420'.

Claims

Patent claims 1. Tool for the manufacture of plastic products, comprising: a metallic tool body; and a hard coating covering at least parts of the metallic tool body, which has a surface on which the plastic product is molded during its manufacture, wherein the surface of the hard coating comprises a structured zone having a structure introduced into the hard coating which is transferred to the plastic product during molding.

2. Tool according to claim 1, wherein the hard material coating comprises a PVD layer and / or a CVD layer.

3. Tool according to claim 1 or 2, wherein the hard coating comprises one or more of the following layers: nitride layer, in particular TiN layer, AlCrN layer, CrN layer or TiAlN layer, carbide layer, nitrocarbide layer, DLC (diamond like carbon) layer or a ta-C (tetrahedral amorphous carbon) layer.

4. Tool according to one of the preceding claims, wherein the structure represents a code, in particular a digital watermark.

5. Tool according to claim 4, wherein the code encodes one or more pieces of information that designate usage and / or recycling information for the plastic product, in particular the plastic product itself, the manufacturer of the plastic product, the manufacturing method of the plastic product, the manufacturing material or materials of the plastic product and / or the contents of a plastic product container.

6. Tool according to one of the preceding claims, wherein the structure encodes an address of an entry for the plastic product in a database.

7. Tool according to one of the preceding claims, wherein the structure forms an aesthetic feature and / or a functional feature of the plastic product.

8. Tool according to one of the preceding claims, wherein the hard coating has a thickness between 1 pm and 50 pm, in particular 2 pm and 20 pm or 4 pm and 10 pm.

9. Tool according to one of the preceding claims, wherein the structure has a structural depth that is at most 90% of the thickness of the hard coating.

10. Tool according to one of the preceding claims, wherein the structure has a structural depth between 0.5 pm and 6 pm, in particular 1 pm and 4 pm or 1 pm and 2 pm.

11. Tool according to any of the preceding claims, wherein the total base area of ​​depressions within the structured zone is equal to or less than 10% of the area of ​​the structured zone.

12. Tool according to one of the preceding claims, wherein the structured zone comprises a cell array consisting of a plurality of first cells and second cells of the same shape, wherein the surface roughness in first cells is twice or greater than the surface roughness in second cells.

13. Tool according to one of the preceding claims, wherein the surface of the hard material coating has several structured zones with identical structure.

14. Tool according to claim 13, wherein the structured zones are arranged distributed over a large part of the surface or over the entire surface of the hard material coating.

15. Tool according to any of the preceding claims, which is an injection molding tool, a blow molding tool or a thermoforming tool.

16. A method for reworking a tool for manufacturing plastic products, comprising a metallic tool body and a hard coating covering at least parts of the metallic tool body, the hard coating having a surface on which the plastic product is molded during its manufacture, wherein the surface of the hard coating comprises a structured zone having a structure introduced into the hard coating which is transferred to the plastic product during molding, the method comprising: Removal of the hard coating; Applying a further hard material coating to the metallic tool body, which covers at least parts of the metallic tool body; and Structuring the further hard material coating, thereby forming another structured zone with a further structure which is transferred into the plastic product during molding, wherein the structure and the further structure are identical or different.

17. The method of claim 16, wherein the removal of the hard coating is carried out chemically.

18. Method according to claim 16 or 17, wherein the application of the further hard material coating is carried out by means of a PVD process and / or a CVD process.

19. Method according to one of claims 16 to 18, wherein the structuring of the further hard material coating is carried out by means of laser ablation.

20. Method according to any one of claims 16 to 19, wherein the structure represents a code, the further structure represents a further code which differs from the code, and the code and the further code encode one or more pieces of information which designate usage and / or recycling information for the plastic product.

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