WO2008047127A1

WO2008047127A1 - Method of embossing a substrate

Info

Publication number: WO2008047127A1
Application number: PCT/GB2007/003976
Authority: WO
Inventors: Michael Stuart Miller; Matthew David Wadsworth
Original assignee: Flotek International Limited
Priority date: 2006-10-18
Filing date: 2007-10-18
Publication date: 2008-04-24
Also published as: GB0620712D0

Abstract

According to the invention there is provided a method of embossing a substrate including the steps of: providing a master having a textured surface;. producing an embossing plate having a textured embossing surface corresponding to the negative of the textured surface of the master by casting; and embossing the substrate with the embossing plate to produce an embossed substrate having a surface texture corresponding to the textured surface of the master.

Description

METHOD OF EMBOSSING A SUBSTRATE

This invention relates to methods of embossing a substrate and also to methods of manufacturing an embossing plate. Traditional embossing processes have used a steel embossing plate which is used to stamp a substrate, thereby imparting a desired texture to the substrate. The texture on the embossing plate necessarily corresponds to the "negative" image of the texture that is embossed into the substrate. The texture on the embossing plate has been produced either by milling or etching the steel plate, and both of these approaches give rise to some significant drawbacks.

Firstly, both of these processes are expensive and time-consuming. Secondly, it is difficult to obtain an appreciation of how the embossed final product will appear until the texture has been milled or etched into the steel embossing plate. However, once the milling or etching process is completed it is costly and time-consuming to make any changes to the original texture. In other words, it is difficult to produce prototypes and to vary the nature of the prototypes as part of an ongoing and iterative design process.

The present invention, in at least some of its embodiments, addresses the above-named problems. According to a first aspect of the invention there is provided a method of embossing a substrate including the steps of: providing a master having a textured surface; producing an embossing plate having a textured embossing surface corresponding to the negative of the textured surface of the master by casting; and embossing the substrate with the embossing plate to produce an embossed substrate having a surface texture corresponding to the textured surface of the master. In this way it is possible to provide an embossing plate with a reasonable expectation that the texture of the embossed substrate will correspond to the texture of the original master. Furthermore, the embossing plate is conveniently and easily produced by the casting process, and thus it is straightforward to vary the surface texture of the embossed substrate by varying the master or producing a different master and then recasting to provide a new embossing plate.

The embossing plate can either be cast "directly" or "indirectly" from the master. In the direct casting variant, the embossing plate may be produced by casting around the textured surface of the master with a hardenable material which is hardened to form the embossing plate. The hardenable material may be hardened to form an embossing plate comprising a ceramic material, preferably a ceramic material reinforced hardened resin. Typically the hardenable material is hardened around the textured surface of the master and subsequently removed therefrom. However, it may also be possible to remove the hardenable material from the textured surface of the master when it is partially hardened, or to destroy the master by a suitable process to reveal the embossing plate.

Preferably, the hardenable material includes a hardenable resin. The hardenable resin may contain particles of one or more materials, and in a preferred embodiment the hardenable material includes particles of ceramic material. Ceramic embossing plates are particularly convenient for relatively high volume production processes.

In indirect processes for the production of the embossing plate, the embossing plate may be produced by i) contacting the textured surface of the master with a first material to produce a first structure having a textured surface corresponding to the negative of the textured surface of the master, ii) contacting the first structure with a second material to produce a second structure having a textured surface corresponding to the textured surface of the master, and iii) casting around the textured surface of the second structure with a hardenable material which is hardened to form the embossing plate. Preferably, the hardenable material includes a hardenable resin, and most preferably the hardenable material consists essentially of a hardenable resin. Preferred examples of a hardenable resin are polyurethane resin or an epoxy resin. Advantageously, the first structure is produced by casting the first material around the textured surface of the master and causing the first material to harden.

Preferably,, a second structure is produced by casting the second material around the textured surface of the second structure causing the second material to harden.

The master may be produced by applying a textured skin to a base. Preferably, the textured skin includes a release backing having relief material attached thereto as a texture, and the release backing is pealed off the base to leave the relief material attached to the base, thereby producing the master. Alternatively, the textured skin may be produced by selective curing of a photopolymer, stereolithography, screen printing on to a substrate, thermopolymer printing, Selective Laser Sintering (SLS) or Laminated Object Manufacture (LOM). The master having a textured surface may be produced by a laser based procedure, a solid object printer, stereolithography, or by milling.

Alternatively, the master may be in the form of a pre-existing textured surface.

During embossing, the embossing plate may be supported on a support structure.

The substrate which is embossed may be a leather or a polymeric material, preferably a vinyl material.

In one embodiment, the master comprises a plurality of discrete areas each having a different texture; the step of embossing the substrate is performed so as to produce an embossed substrate having a plurality of discrete areas each having the different textures; and the embossed substrate is divided into the plurality of discrete areas. In this way, a number of prototype textures can be produced from a single embossing plate. This procedure can be incorporated as part of a design process in which designers can assess the actual appearance of prototype textures and experiment with them, for example as part of a market research process. Once a design is chosen, a full size embossing plate can be conveniently made using the principles described herein.

According to a second aspect of the invention there is provided a method of manufacturing an embossing plate including the steps of: providing a master having a textured surface; and producing an embossing plate having a textured surface corresponding to the negative of the textured surface of the master by casting. Whilst the invention has been described above, it extends to any inventive combination or sub-combination of the features set out above or in the following description or drawings or claims.

Embodiments of methods in accordance with the invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows steps in the production of an embossing plate of the invention, namely a) a textured skin b) texture applied to a base sheet c) casting around the textured base sheet to produce a negative interim cast d) removal of the negative interim cast from the textured base sheet e) inversion of the negative interim cast f) formation of an embossing plate precursor sheet g) removal of the embossing plate precursor sheet from the negative interim cast h) inversion of the embossing plate precursor sheet i) casting of the embossing plate j) the embossing plate after removal from the embossing plate precursor sheet and k) embossing of a substrate with the embossing plate;

Figure 2 shows a) casting of a resin around a textured substrate to form an embossing plate and b) removal of the embossing plate from the textured substrate; and

Figure 3 is a plan view of a substrate having a number of discrete areas each having a different texture.

Figure 1 depicts various stages in an "indirect" process for the production of an embossing plate of the invention. Figure 1a) shows a release backing 10 having relief material 12 thereon, the relief material being distributed so as to form an appropriate texture. The relief material is then applied to a suitable base sheet 14, such as a PVC sheet, and the release backing 10 is removed to produce, as shown in Figure 1b), a positive master 16 having a textured surface.

The texturing technique in which the relief material is applied from a release backing is known commercially as Flotek™, and is further exemplified in International publications WO 99/028113 and WO 00/058066, the contents of both of which are herein incorporated by reference. In a next step, shown in Figure 1c), the positive master 16 is shuttered off using appropriate shuttering 18, and a hardenable material 20 is poured into the shuttered area. The hardenable material 20 may be a polymeric precursor and/or a resin which is cured to produce a "negative" interim cast 22. Silicone rubber is a suitable example. The negative interim cast 22 is removed from the positive master 16 (Figure 1d) and is inverted (Figure 1e). The skilled reader will appreciate that the negative interim cast 22 has a texture which corresponds to the negative image of the positive master 16. Next, as shown in Figure 1f), appropriate shuttering 24 is provided around the negative interim cast 22, and an embossing plate precursor sheet 26 is produced using an appropriate technique, such as casting or imprinting the texture of the negative interim cast

22 onto a partially hardened mass. Silicone rubber may be used to produce the embossing plate precursor sheet. The embossing plate precursor sheet 26 is then removed from the negative interim cast 22 (Figure 1g) and is then inverted and shuttered using appropriate shuttering 28 (Figure 1h). An appropriate material 30 is then cast into the shuttering 28 (Figure 1i) and is caused to harden to produce an embossing plate 32 which is removed from contact with the embossing plate precursor sheet 26 (Figure 1j). The skilled reader will appreciate that there are many candidate materials for use in the casting step shown in Figure 1i). Curable polymeric precursors and/or resins, such as polyurethane resin or epoxy resin, are particularly suitable. Embossing plates fabricated from epoxy resin or polyurethane resin are particularly useful for relatively low volume production runs. The embossing plate 32 is subsequently used to emboss a substrate 34 such as a leather or vinyl substrate. As shown in Figure 1k), the embossed substrate 34 is removed from contact with the embossing plate 32. Since the embossing plate 32 has a texture corresponding to the negative image of the texture of the original positive master 16, the embossed substrate 34 is provided with a surface texture corresponding to the positive image of the texture of the positive master 16. Figure 2 depicts the production of an embossing plate by a "direct" process. Figure 2a) shows a positive master 40 comprising a base sheet 42 having a texture in the form of relief material 44 thereon. The texture positive master 40 can be produced in the same way as the texture positive master 16 shown in Figure 1. Appropriate shuttering 46 is provided and a cast is made by pouring a hardenable material 48 into the area defined by the shuttering 46. The hardenable material 48 is either partially or fully hardened, and removed from the positive master 40 to provide, as shown in Figure 2b), a hardened embossing plate 50 having a texture in the form of the negative image of the texture of the positive master 40. The embossing plate 50 is subsequently used in embossing operations. It is particularly preferred to produce an embossing plate of a ceramic material. This can be provided by utilising a suitable resin, such as an epoxy resin, having dispersed therein a ceramic whisker. Further exemplification of suitable hardenable materials, including but not limited to ceramics or ceramic containing compositions, can be found in US 4,919,388, the content of which is herein incorporated by reference. It should be noted that US 4,919,388 is entirely concerned with the production of a mould liner for a metal mould, and does not suggest that an embossing procedure might be contemplated. Ceramic based embossing piates constitute an extremely convenient means by which relatively high volume production can be accomplished.

Figure 3 depicts an embossing plate 60 which comprises a plurality of discrete areas 60a-60l. Each discrete area 60a-60l has a different surface texture (not shown) associated with it. Thus, a substrate which is embossed with the embossing plate 60 can be produced which also has a plurality of discrete areas each having a different texture. The embossed substrate can be conveniently divided up to provide a plurality of samples, each sample corresponding to a discrete area and having a different texture. The samples can be assessed for design purposes and utilised as part of a market research process, for example by working the samples up into prototype products.

Embossing plates manufactured from polyurethane or a resin are particularly suited for this application, which is inherently low volume. Once a design is chosen, an embossing plate can be produced which is entirely dedicated to the chosen texture, and high volume production can be commenced. Ceramic based embossing plates are particularly useful for the high volume production. The production of textured masters using techniques such as the relief material technique described in International publications WO 99/028113 and

WO 00/058066 is particularly advantageous because designs can be produced in software prior to realisation under computer control. Thus, it is straightforward to provide a master having the plurality of discrete areas shown in Figure 3, and it is relatively easy to alter a design using software.

The present invention has applications in many areas of commerce, such as vehicle interiors and furniture production. The convenient and economic production of embossing plates suitable for low volume production means that personalised embossing may be provided by the present invention. In that regard, it is again advantageous that textures can be realised conveniently from designs that are stored in software and which are easily altered and/or may be accessed in a desired sequence.

Claims

1. A method of embossing a substrate including the steps of: providing a master having a textured surface; producing an embossing plate having a textured embossing surface corresponding to the negative of the textured surface of the master by casting; and embossing the substrate with the embossing plate to produce an embossed substrate having a surface texture corresponding to the textured surface of the master.

2. A method according to claim 1 in which the embossing plate is produced by casting around the textured surface of the master with a hardenable material which is hardened to form the embossing plate.

3. A method according to claim 2 in which the hardenable material is hardened to form the embossing plate comprises a ceramic material, preferably a ceramic material reinforced hardened resin.

4. A method according to claim 2 or claim 3 in which the hardenable material includes a hardenable resin.

5. A method according to claim 4 in which the hardenable resin contains particles of one or more materials.

6. A method according to claim 5 in which the hardenable material includes particles of a ceramic material.

7. A method according to claim 1 in which the embossing plate is produced by i) contacting the textured surface of the master with a first material to produce a first structure having a textured surface corresponding to the negative of the textured surface of the master, ii) contacting the first structure with a second material to produce a second structure having a textured surface corresponding to the textured surface of the master, and iii) casting around the textured surface of the second structure with a hardenable material which is hardened to form the embossing plate.

8. A method according to claim 7 in which the hardenable material includes a hardenable resin, and preferably consists essentially of a hardenable resin.

9. A method according to claim 8 in which the hardenable resin is polyurethane resin or an epoxy resin.

10. A method according to any one of claims 7 to 9 in which the first structure is produced by casting the first material around the textured surface of the master and causing the first material to harden.

11. A method according to any one of claims 7 to 10 in which the second structure is produced by casting the second material around the textured surface of the second structure and causing the second material to harden.

12. A method according to any previous claim in which the master is produced by applying a textured skin to a base.

13. A method according to claim 12 in which the textured skin includes a release backing having relief material attached thereto as a texture, and the release backing is peeled off the base to leave the relief material attached to the base, thereby producing the master.

14. A method according to claim 12 in which the textured skin is produced by selective curing of a photopolymer, stereolithography, screen printing onto a substrate, thermopolymer printing, Selective Laser Sintering (SLS) or a Laminated Object Manufacture (LOM).

15. A method according to any one of claims 1 to 12 in which the master having a textured surface is produced by a laser based procedure, a solid object printer, stereolithography or by milling.

16. A method according to any previous claim in which during embossing the embossing plate is supported on a support structure.

17. A method according to any previous claim in which the substrate which is embossed is a leather or a polymeric material, preferably a vinyl material.

18. A method according to any previous claim in which the master comprises a plurality of discrete areas each having a different texture; the step of embossing the substrate is performed so as to produce an embossed substrate having a plurality of discrete areas each having the different textures; and the embossed substrate is divided into the plurality of discrete areas.

19. A method of manufacturing an embossing plate including the steps of: providing a master having a textured surface; and producing an embossing plate having a textured surface corresponding to the negative of the textured surface of the master by casting.