Production method of hook-and-loop fastener molding die, and hook-and-loop fastener and production method thereof

Abstract

To provide a novel technique that contributes to improvement of the forming accuracy of engagement elements of a hook-and-loop fastener.SOLUTION: A production method of a hook-and-loop fastener molding die 9 includes: forming an electroforming sleeve 7 on an electroforming mold 6 having a group of sacrificial parts 3 having electrical insulation properties formed on the support face 4a of the metallic sleeve 4 so as to form the electroforming sleeve 7 on the support face 4a of the metallic sleeve 4; allowing each sacrificial part 3 of the group of sacrificial parts 3 to be buried at least partially in the electroforming sleeve 7; and acquiring the hook-and-loop fastener molding die 9 in which a group of molding cavities 8 corresponding to the group of sacrificial parts 3 is formed in the electroforming sleeve 7 while removing the group of sacrificial parts 3 of the electroforming mold 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a mold for molding a hook-and-loop fastener, and a method for manufacturing the hook-and-loop fastener. [Background technology]

[0002] Patent Document 1 discloses a hook-and-loop fastener having an engaging element with a claw portion protruding from the outer periphery of the engaging head by primary and secondary molding (see, for example, FIG. 2 in the document). A cylinder having a through hole and a concave groove portion as shown in FIG. 8 of the document is used for molding the hook-and-loop fastener (see also FIG. 7 in the document). As shown in FIG. 36 of the document, a form using a two-layer cylinder with an outer and inner layer is also disclosed, and the structure of the cylinder is shown in FIG. 37 of the document.

[0003] Incidentally, Patent Document 2 discloses a method for releasing a cylindrical member, although it is unrelated to hook-and-loop fasteners. It discloses that an insulating material is placed on a cylindrical metal matrix, an electroformed film is formed on the side of the matrix so as to include a recessed or hole shape using the insulating material, and the electroformed film is released from the matrix using the recessed or hole shape (see Figures 1 and 2 in the same document). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 110127 [Patent Document 2] JP 2019-44220 A Summary of the Invention [Problem to be solved by the invention]

[0005] It was extremely difficult to manufacture the cylinder disclosed in Patent Document 1 with high accuracy. With regard to the form shown in Figure 37 of the same document, it was difficult to ensure the alignment of the through hole of the outer cylinder with the groove of the inner cylinder, and there was variation in the position of the claw (formed by the groove) with respect to the stem of the engaging element (formed by the through hole). Even in the actually manufactured hook-and-loop fastener, it was possible to observe that the position of the claw with respect to the stem differed depending on the position of the engaging element in the plane of the hook-and-loop fastener, and there was a demand for reducing the variation in the shape of the engaging element of the hook-and-loop fastener.

[0006] As can be seen from the above non-limiting illustrative description, there is a demand for new technology that contributes to improving the shape precision of engaging elements of hook-and-loop fasteners. [Means for solving the problem]

[0007] A method of manufacturing a hook-and-loop fastener molding die according to one embodiment of the present disclosure includes forming an electroforming film on an electroforming die having a group of electrically insulating sacrificial parts formed on the support surface of a conductive support material, such that the electroforming film is formed on the support surface of the support material and each of the group of sacrificial parts is at least partially embedded in the electroforming film, and removing the group of sacrificial parts from the electroforming die to obtain a hook-and-loop fastener molding die having a group of molding cavities formed in the electroforming film corresponding to the group of sacrificial parts.

[0008] A method for producing a hook-and-loop fastener according to another aspect of the present disclosure produces a hook-and-loop fastener by using the above-mentioned hook-and-loop fastener molding die. This disclosure also relates to a hook-and-loop fastener produced thereby.

[0009] The method of manufacturing the hook-and-loop fastener mold can further include manufacturing an electroforming mold. Manufacturing the electroforming mold can include molding a group of sacrificial portions on a support surface of a support material.

[0010] In some cases, forming a group of sacrificial portions on a support surface of the support material includes a 3D printer head forming a group of sacrificial portions on the support surface of the support material based on the ejection of a light or heat curable material.

[0011] In some cases, forming the group of sacrificial portions on the support surface of the support material includes a 3D printer head forming a first subset of the group of sacrificial portions in a first region of the support surface and, subsequent to forming the first subset, forming a second subset of the group of sacrificial portions in a second region of the support surface adjacent to the first region, wherein the plurality of sacrificial portions in the first subset and the plurality of sacrificial portions in the second subset are complementary positioned to define a non-linear boundary between the first and second regions.

[0012] In some cases, the 3D printer head is operable to cause light or heat curable material dispensed at different times to coalesce in mid-air and land on a support surface.

[0013] In some cases, the support is a flexible metal sleeve. The 3D printer head can print a set of sacrificial features on a flat surface of the support surface formed by deformation of the metal sleeve. A transport mechanism can be employed to move (e.g., cycle) the metal sleeve between a position directly beneath the 3D printer head and another position (e.g., a position directly beneath a UV light source).

[0014] The method of manufacturing a hook-and-loop fastener mold can further include removing the electroformed film from the support. In some cases, the electroformed film is formed as an electroformed sleeve.

[0015] The method for manufacturing a hook-and-loop fastener molding die can further include polishing the uneven surface of the electroformed film. In some cases, the electroformed film is formed to have an uneven surface on the side away from the support surface.

[0016] In some cases, each sacrificial member of the group of sacrificial members includes a stem portion upstanding from the support surface and at least one prong portion connected to the stem portion on the support surface.

[0017] In some cases, each molding cavity of the group of molding cavities includes a stem molding space having a constant opening diameter formed by a stem portion, and a claw portion molding space formed by one or more claw portions.

[0018] In some cases, each mold cavity of a group of mold cavities penetrates the electroformed membrane.

[0019] In some cases, the support is a flexible metal sleeve.

[0020] A hook-and-loop fastener according to another embodiment of the present disclosure includes a base layer and a group of engaging elements formed on a main surface of the base layer. Each of the engaging elements may include a cylindrical stem portion protruding from the base layer and one or more claw portions connected to the top of the stem portion. The stem portion may have a substantially constant diameter in a direction away from the base layer.

[0021] Preferably, the connection positions of one or more claws to the top of the stem are consistent throughout the group of engaging elements. Advantageously, the arrangement density of the engaging elements is within the range of 150 pieces / cm2 to 400 pieces / cm2. Effect of the Invention

[0022] According to one aspect of the present disclosure, a new technology is provided that contributes to improving the shape accuracy of engaging elements of a hook-and-loop fastener. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic flowchart of a method for manufacturing a hook-and-loop fastener molding die according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram of an electroforming mold manufacturing apparatus. [Diagram 3] FIG. 2 is a schematic side view of a sacrificial part. [Figure 4] FIG. 2 is a schematic top view of a sacrificial part. [Diagram 5] 13A to 13C are schematic diagrams showing a process for forming a sacrificial portion. [Figure 6]FIG. 13 is a schematic diagram illustrating the sequential formation of a subset of features in adjacent regions of a metallic sleeve. [Figure 7] FIG. 2 is a schematic diagram of an electroforming mold. [Figure 8] FIG. 2 is a schematic process diagram showing an electroforming process. [Figure 9] FIG. 2 is a schematic diagram showing an electroformed sleeve with a sacrificial portion obtained by an electroforming process. [Figure 10] FIG. 13 is a process diagram for removing the sacrificial portion. [Figure 11] A schematic diagram showing an electroformed sleeve with a sacrificial portion removed, also illustrating a grinder grinding the outer surface of the electroformed sleeve. [Figure 12] FIG. 2 is a schematic diagram of a hook-and-loop fastener manufacturing apparatus. [Figure 13] 2 is a schematic partial cross-sectional view of a hook-and-loop fastener. FIG. [Figure 14] FIG. 2 is a top view of an engaging element of the hook-and-loop fastener. [Figure 15] FIG. 13 is a schematic perspective view of a sacrificial portion molded onto a metallic sleeve. [Figure 16] 1 is a schematic perspective view of an engaging element rising from a base layer of a hook-and-loop fastener. FIG. [Figure 17] 13 is a schematic perspective view showing a modified example of an engaging element. FIG. [Figure 18] 1 is a photograph showing the upper surface of a hook-and-loop fastener according to an embodiment of the present invention. [Figure 19] 1 is a photograph showing a side view of a hook-and-loop fastener according to an embodiment of the present invention. [Figure 20] FIG. 1 is a schematic diagram showing that a die wheel is constructed from an inner and an outer cylinder. [Figure 21] FIG. 13 is a schematic diagram showing drilling of a hole in an outer cylinder by an electron beam. [Figure 22] 13 is a schematic diagram showing that there is variation in the position of the claw portion in the engaging element. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, non-limiting embodiments and features of the present invention will be described with reference to the drawings. Those skilled in the art can combine the embodiments and / or features without excessive explanation, and can also understand the synergistic effects of such combinations. In principle, overlapping descriptions between embodiments will be omitted. The reference drawings are primarily intended to describe the invention, and are simplified for the convenience of drawing.

[0025] A method for manufacturing a die for molding a hook-and-loop fastener will be described below. In an exemplary method, as shown in FIG. 1, an electroforming die including a group of sacrificial parts is manufactured (S1), an electroforming process is performed using the electroforming die (S2), and then the group of sacrificial parts in the electroforming die are removed (S3). Each sacrificial part is formed by an appropriate molding method (e.g., 3D (three-dimensional) molding technology, injection molding, or photolithography), and the sacrificial parts are removed (typically by chemical treatment) after the electroforming process, to obtain an electroformed film in which individual molding cavities corresponding to each sacrificial part are formed. By using this electroformed film as a die for molding a hook-and-loop fastener, a hook-and-loop fastener in which a group of engaging elements with high uniformity in shape / dimensions is formed can be manufactured. The sacrificial parts are made of any material suitable for molding that has electrical insulation properties.

[0026] The shape / dimension accuracy of each molded cavity (and thus the shape / dimension accuracy of each engaging element) depends on the shape / dimension accuracy of each sacrificial part, but the accuracy of currently available molding methods is sufficiently high. In fact, the sacrificial part 3 can be molded with sufficient accuracy compared to cutting methods such as electron beams, and as a result, the shape / dimension accuracy of the molded cavity is also improved.

[0027] It should be noted that while this specification primarily describes using 3D printing techniques, such as a 3D printer head, to create a group of sacrificial portions, other methods (e.g., injection molding, photolithography) may also be used.

[0028] The following description will be given with reference to FIG. 2. The electroforming mold manufacturing apparatus 100 includes a 3D printer head 1, a UV light source 2, and a conveying mechanism. The 3D printer head 1 forms a group of sacrificial parts 3 on a support surface 4a of a metal sleeve 4 based on the discharge of a photocurable material. The 3D printer head 1 has, for example, a group of nozzles arranged two-dimensionally, and can discharge the photocurable material from one or more selected nozzles. This allows a subset of sacrificial parts 3 to be formed in a two-dimensional range. There is no particular limitation on the specific structure and mechanism of the 3D printer head 1, and various types of 3D printer heads can be used. For example, a type of 3D printer head that scans a single nozzle two-dimensionally can also be used. The photocurable material is typically a UV-curable resin (preferably a negative resist). Of course, a thermosetting material can be used instead of the photocurable material, and in this case, a heat source (for example, a heater, a far-infrared laser, etc.) is used for curing the material. It is also contemplated that individual sacrificial portions 3 may be injection molded and attached to the metal sleeve 4 .

[0029] The UV light source 2 is built into the 3D printer head 1 or is provided independently. The UV curable resin (e.g., resist) discharged from the nozzle of the 3D printer head 1 is cured (typically semi-cured) by receiving the UV light emitted from the UV light source 2. When a UV laser light source (e.g., wavelength 355 nm) is used as the UV light source 2, the laser spot diameter, laser emission timing, and laser intensity can be controlled with high precision. Preferably, software- or hardware-based sequence control is implemented for the timing of material discharge from the 3D printer head 1 and the timing of UV light emission.

[0030] The transport mechanism may have a movable stage (not shown) and a conveyor 5 mounted on the movable stage. The position of the conveyor 5 relative to the 3D printer head 1 and the UV light source 2 changes based on the movement of the movable stage. The movable stage may be capable of reciprocating in a certain transport direction (for example, the direction in which the 3D printer head 1 and the UV light source 2 are arranged side by side). The conveyor 5 includes a pair of rolls 5a, 5b, and supports the metal sleeve 4 so that it can be transported in the circumferential direction. The metal sleeve 4 is simply stretched between the two rolls 5a, 5b as a conveyor belt. By moving the stage, the support surface 4a on which the sacrificial part 3 is not arranged can be supplied to a position directly below the 3D printer head 1, and similarly, the support surface 4a on which the sacrificial part 3 is arranged can be sent from a position directly below the 3D printer head 1 to a position directly below the UV light source 2.

[0031] Advantageously, the metal sleeve 4 is supported by the conveyor 5 in such a way that its support surface 4a extends flat between the two rolls 5a, 5b. The deformation of the metal sleeve 4 forms a flat surface on the support surface 4a, on which the 3D printer head 1 prints a group of sacrificial parts 3. A generic 3D printer head 1 can be used to print a group of sacrificial parts 3, avoiding a special design of the 3D printer head 1 for printing sacrificial parts 3 on a curved surface. It is also possible to arrange the 3D printer head 1 and the UV light source 2 movable relative to the conveyor 5.

[0032] The metal sleeve 4 is a hollow cylinder having a support surface 4a as an outer surface and an opposite inner surface 4b. The metal sleeve 4 is preferably flexible and can bend and curved freely. The thickness of the metal sleeve 4 is, for example, within a range of 0.05 mm to 0.3 mm, and preferably within a range of 0.1 mm to 0.2 mm. As a support material for supporting the sacrificial part 3, a material other than the metal sleeve, for example, a metal flat plate, can also be used.

[0033] As described below, the 3D printer head 1 may be configured to print different areas (e.g., Q N ,Q N-1 ,Q N-2(N is a natural number equal to or greater than 2)), a subset of the sacrificial parts 3 may be formed. In the case of N=3, exemplarily, the metal sleeve 4 is first placed on the conveyor 5 so that Q1, which is the first region of the support surface 4a, is a flat surface between the two rolls 5a and 5b. Thereafter, the stage is moved to move the support surface 4a of the first region Q1 back and forth between a position directly below the 3D printer head 1 and a position directly below the UV light source 2, thereby forming a desired number of sacrificial parts 3 on the support surface 4a of the first region Q1. Next, the metal sleeve 4 is placed on the conveyor 5 so that Q2, which is the second region of the support surface 4a, is a flat surface between the two rolls 5a and 5b by the rotation of the two rolls 5a and 5b. As in the first region, a desired number of sacrificial parts 3 are also formed on the support surface 4a of the second region. In the third region, the sacrificial parts 3 are also formed in the same procedure.

[0034] The maximum number of sacrificial parts 3 that the 3D printer head 1 can print at one time is less than the total number of sacrificial parts 3 to be placed on the support surface 4a of the metal sleeve 4 (for example, approximately 1 / 3 to 1 / 10 of that total number), and by utilizing the small 3D printer head 1 based on the movement of the stage relative to the above-mentioned 3D printer head 1 and UV light source 2 and the rotation of the metal sleeve 4 by the conveyor 5, sacrificial parts 3 can be efficiently formed over the entire area of ​​the metal sleeve 4.

[0035] The three-dimensional shape of the sacrificial portion 3 is set according to the final shape of the target engaging element of the hook-and-loop fastener or the shape of a precursor of the engaging element. In this specification, with a view to a form in which an engaging element temporarily molded by a hook-and-loop fastener molding die is additionally molded, such as secondarily or tertiarily, the engaging element before such additional molding (i.e., as molded by the hook-and-loop fastener molding die) is called a "precursor."

[0036] The sacrificial portion 3 has a height direction that coincides with the center line CL of the sacrificial portion 3 and a width or diameter direction perpendicular to the height direction. The sacrificial portion 3 has a width or diameter that varies in the height direction, which will be reflected in the shape of the molding cavity and the engaging element (or a precursor of the engaging element).

[0037] Exemplarily, the sacrificial portion 3 includes a substantially cylindrical stem portion 31 standing from the support surface 4a of the metal sleeve 4, and at least one or more claw portions 32, 33 connected to the stem portion 31 on the support surface 4a (see Figs. 3 and 4). The stem portion 31 has a top surface 31a and a side surface 31b. The side surface 31b stands perpendicular to the support surface 4a of the metal sleeve 4, and forms an angle of approximately 90° (for example, within a range of 89° to 101°) with respect to the support surface 4a. The support surface 4a described here is a horizontal plane extending between the rolls 5a and 5b as shown in Fig. 1.

[0038] The top surface 31a of the stem portion 31 is a curved surface approaching the support surface 4a as it extends radially outward from the center line CL, or a flat surface parallel to the support surface 4a. A rounded edge 31c may be formed between the top surface 31a and the side surface 31b of the stem portion 31. The curvature of the top surface 31a and / or edge 31c may be the result of the stem portion 31 being formed by dropping material particles using the 3D printer head 1. In addition, in terms of its relationship with the stem portion 31, the claw portion may be called a "radial protrusion."

[0039] Although the details of the dimensions of the sacrificial portion 3 can be changed as appropriate, an exemplary embodiment is as follows. The sacrificial portion 3 has a first height H1 which is the maximum height of the stem portion 31, and a second height H2 which is the maximum height of the claw portions 32, 33. The first height H1 may be in the range of 0.3 to 0.8 mm, more preferably in the range of 0.4 to 0.6 mm. The second height H2 may be in the range of 0.01 to 0.06 mm, more preferably in the range of 0.02 to 0.04 mm. The sacrificial portion 3 has a first width or diameter W1 of the stem portion 31 alone, and a second width or diameter W2 which is larger at the portion where the claw portions 32, 33 are connected to the stem portion 31. The first width or diameter W1 may be in the range of 100 μm to 200 μm, preferably in the range of 130 μm to 170 μm. The second width or diameter W2 may be in the range of 150 μm to 300 μm, and preferably in the range of 200 μm to 250 μm. The total amount of protrusion of the claw portions 32, 33 from the peripheral surface of the stem portion 31 may be about 25% to 50% of the diameter of the stem portion 31.

[0040] A case where a 3D printer head 1 is used to form the sacrificial part 3 will be described with reference to Figs. 5 and 6. As shown in Fig. 5(a), material particles (of a photocurable material) discharged from the nozzle of the 3D printer head 1 land on the support surface 4a of the metal sleeve 4 to become the claw portion 32. At the same or different timing as the discharge of the material particles from Fig. 5(a), as shown in Fig. 5(b), material particles are discharged from the nozzle of the 3D printer head 1 and land on the support surface 4a of the metal sleeve 4 to become the claw portion 33. The area on the support surface 4a where the sacrificial part 3 is to be formed is placed directly under the 3D printer head 1, and after the material particles are landed as shown in Figs. 5(a) and (b), the stage is moved to move the area directly under the UV light source 2, as described later, to cure the material particles with UV. This procedure can be repeated to pile up the material particles in the height direction so that the claw portion 33 reaches the desired height H2.

[0041] Simultaneously with or after the ejection of the material particles in FIG. 5(a) and FIG. 5(b), a series of material particles are ejected from the 3D printer head 1 at different timings as shown in FIG. 5(c), which then combine in a chain in the air and land on the support surface 4a of the metal sleeve 4 to become the stem portion 31. By combining the material particles in a chain in the air in this way, it is possible to obtain droplets of large material particles even with a small nozzle. Therefore, even if it is desired to form the pitch of the stem portion 31 narrowly (when the nozzle diameter cannot be increased), the stem portion 31 can be made to have a desired thickness. After the series of material particles combine in the air and land on the support surface 4a, the stage is moved to move the region directly under the UV light source 2, as with the claw portion 33, to UV-cure the material particles. This procedure can be repeated to pile up the material particles in the height direction so that the stem portion 31 reaches the desired height H1. Furthermore, by forming the stem portion 31 thick by combining the material particles in a chain-like manner in the air, it is possible to form the claw portion 33 which is relatively small compared to the diameter of the stem portion 31. By having the small claw portion 33, sufficient engagement strength can be obtained when the basis weight of the female member (loop or nonwoven fabric) which engages with the hook-and-loop fastener is small.

[0042] 5(a)-(c), the material particles are exposed to UV light while falling toward or after landing on the support surface 4a of the metal sleeve 4 and semi-cured. Additionally or alternatively, after the entire sacrificial portion 3 shown in FIG. 5(c) is formed, a curing process is performed to further promote the curing of the sacrificial portion 3. The width or diameter of the stem portion 31 can also be fine-tuned based on the adjustment of the luminosity of the UV light emitted from the light source. In this case, the stem portion 31 has a width or diameter that is correlated with the UV illumination conditions as well as the discharge conditions of the material particles from the 3D printer head 1.

[0043] The 3D printer head 1 is configured to print different areas (e.g., Q N ,Q N-1 ,Q N-2 (N is a natural number equal to or greater than 2)), a subset of the sacrificial portions 3 may be formed. With reference to FIG. 6, when N=3, the 3D printer head 1 forms a first subset of 24 sacrificial portions 3 in the first region Q1, then forms a second subset of 24 sacrificial portions 3 in the second region Q2, and then forms a third subset of 24 sacrificial portions 3 in the third region Q3. The total of 24 sacrificial portions 3 in the first region Q1 and the total of 24 sacrificial portions 3 in the second region Q2 are arranged complementarily (in the illustrated example, in a complementary zigzag shape) so that a non-linear boundary line can be drawn between the first region Q1 and the second region Q2. Similarly, the total of 24 sacrificial portions 3 in the second region Q2 and the total of 24 sacrificial portions 3 in the third region Q3 are arranged complementarily (in the illustrated example, in a complementary zigzag shape) so that a non-linear boundary line can be drawn between the second region Q2 and the third region Q3. This makes it more difficult to visually distinguish between the first region Q1, the second region Q2, and the third region Q3. When N=3, the total number of sacrificial portions 3 is 72. The same explanation as above applies when N=2, 4, 5, 6, 7, etc. The number of sacrificial portions in one region can be increased or decreased, and it is also possible to form different numbers of sacrificial portions in different regions. The non-linear boundary line is not limited to a zigzag line and may be an uneven line. Each sacrificial portion 3 may be addressable by row numbers R1 to R12 and column numbers C1 to C5.

[0044] A group of sacrificial portions 3 is formed two-dimensionally and regularly on the support surface 4a of the metal sleeve 4. The density of the group of sacrificial portions 3 on the support surface 4a of the metal sleeve 4 is set to correspond to the density of the engagement elements of the target hook-and-loop fastener. Preferably, the group of sacrificial portions 3 is formed uniformly over the entire support surface 4a of the metal sleeve 4, which promotes efficient manufacturing of the hook-and-loop fastener. In some cases, when the support surface 4a of the metal sleeve 4 is divided into a plurality of regions, there is little difference in the density of the sacrificial portions 3 in each region, for example, compared with the region with the maximum density, the density of all the other regions is within a range between the maximum density x 0.95 and the maximum density x 1.05.

[0045] By making the metal sleeve 4 sufficiently thin and flexible, it can be removed from the rolls 5a, 5b relatively easily. The sacrificial portion 3 does not necessarily adhere strongly to the metal sleeve 4, and there is a risk that it will fall off from the metal sleeve 4 due to external forces or deformation of the metal sleeve 4. Therefore, it is desirable to handle the metal sleeve 4 carefully so that the sacrificial portion 3 does not fall off. The metal sleeve 4 can also be temporarily fixed to the rolls 5a, 5b using double-sided seals or mechanical fasteners (e.g., screws, bolts).

[0046] The electroforming mold 6 shown in Fig. 7 is manufactured by the above-mentioned method or another method different from the above. Although the metal sleeve 4 of the electroforming mold 6 can be reused repeatedly, the group of sacrificial parts 3 cannot be reused repeatedly. Therefore, it is practical to efficiently manufacture the group of sacrificial parts 3 by combining the above-mentioned 3D printer head 1, UV light source 2, and transport mechanism.

[0047] FIG. 8 shows a schematic diagram of the electroforming process. The electroforming process is similar to electroplating, except that the electroformed product (electroformed film) is removed from the electroforming die 6. An appropriate electrolyte 52 is stored in an electroforming tank 51, and the electroforming die 6 is immersed in the electrolyte. During the limited time that the electroforming die 6 is immersed in the electrolyte, the sacrificial portion 3 of the electroforming die 6 is not dissolved in the electrolyte. The metal sleeve 4 of the electroforming die 6 is connected to the cathode of a DC power source, and a soluble or insoluble electrode (e.g., nickel metal bar) 53 of the metal ion supply source is connected to the anode of the DC power source. The nickel metal bar can also be placed in a conductive mesh cage, and the cage can be connected to the anode. Metal ions (e.g., nickel ions) dissolved from the electrode 53 into the electrolyte 52 migrate toward the electroforming die 6 and are deposited on the support surface 4a of the metal sleeve 4. In this manner, the electroformed sleeve 7 is formed on the support surface 4a of the metal sleeve 4. The electroformed sleeve 7 adheres to the support surface 4a of the metal sleeve 4 to an extent that allows peeling of the electroformed sleeve 7. Metals other than nickel (for example, nickel-tungsten alloy, nickel-iron alloy) can also be used as the material for the electroformed sleeve 7.

[0048] Each sacrificial portion 3 of the group of sacrificial portions 3 of the electroforming mold 6 may be at least partially embedded in the electroformed sleeve 7. Preferably, the entire sacrificial portion 3 is not embedded in the electroformed sleeve 7, and the top portion 31t of the stem portion 31 is not embedded in the electroformed sleeve 7. This prevents the molding cavity from being reduced in diameter or narrowed in width in correspondence with the edge 31c of the stem portion 31. Although this increases the burden or cost, it is possible to form a molding cavity penetrating the electroformed sleeve 7 by grinding the surface of the electroformed sleeve 7, even if the entire sacrificial portion 3 is embedded in the electroformed sleeve 7.

[0049] 9 shows a schematic diagram of the electroformed sleeve 7 removed from the metal sleeve 4, i.e., a semi-finished product of the die for molding a hook-and-loop fastener. The metal sleeve 4 may be softer than the electroformed sleeve 7. In this case, the electroformed sleeve 7 is removed from the metal sleeve 4 by peeling the electroformed sleeve 7 from the metal sleeve 4. The electroformed sleeve 7 may be softer than the metal sleeve 4. In this case, the electroformed sleeve 7 is removed from the metal sleeve 4 by peeling the electroformed sleeve 7 from the metal sleeve 4.

[0050] The sacrificial portion 3 is embedded in the electroformed sleeve 7, i.e., the electroformed sleeve 7 and the sacrificial portion 3 are integrated. The electroformed sleeve 7 has an outer surface 7a and an inner surface 7b. The electroformed sleeve 7 is formed radially outward from the metal sleeve 4, and therefore does not cover the contact surface of the sacrificial portion 3 with the metal sleeve 4. As a result, the bottom surface 3j of the sacrificial portion 3 is regularly exposed on the inner surface 7b of the electroformed sleeve 7. When the top portion 31t of the stem portion 31 is not embedded in the electroformed sleeve 7, the top surface 31a protrudes from the outer surface 7a of the electroformed sleeve 7. The bottom surface 3j and the top portion 31t of the sacrificial portion 3 are regularly arranged in a two-dimensional manner on each surface of the electroformed sleeve 7. The inner surface 7b may be a curved surface that is smooth and has no irregularities. The outer surface 7a may be a curved surface (convex and concave surface) that is uneven compared to the inner surface 7b. The degree of protrusion of the top portion 31t may be non-uniform.

[0051] In the electroforming process, current tends to flow near the sacrificial portion 3, which tends to cause the electroformed sleeve 7 to be formed thick near the sacrificial portion 3. From this perspective, it is advisable to intentionally form the height of the sacrificial portion 3 high, and also in this respect, it is preferable that the top portion 31t of the stem portion 31 is not embedded in the electroformed sleeve 7. For convenience of drawing, the variation in thickness of the electroformed sleeve 7 is not explicitly shown.

[0052] FIG. 10 shows a non-limiting example of chemical treatment for removing the sacrificial portion 3 from the electroformed sleeve 7. As shown in FIG. 10, the electroformed sleeve 7 with the sacrificial portion 3 embedded therein is immersed in a solution 200 of an acid, an alkali, an organic solvent, or another type of solvent to dissolve or swell the sacrificial portion 3. In this manner, a group of sacrificial portions 3 are removed to obtain an electroformed sleeve 7 (i.e., a mold for forming a hook-and-loop fastener) with a group of molding cavities 8 formed therein. Various other methods such as dry etching can also be used to remove the sacrificial portion 3. An adhesive tape can also be used to remove the sacrificial portion 3. For example, an adhesive tape is attached to the inner surface 7b of the electroformed sleeve 7, and the adhesive tape is peeled off to remove the sacrificial portion 3 from the electroformed sleeve 7. Other methods can also be used.

[0053] FIG. 11 shows the electroformed sleeve 7 from which the sacrificial portion 3 has been removed, i.e., a die for molding a hook-and-loop fastener. The molding cavity 8 penetrates the electroformed sleeve 7 between the outer surface 7a and the inner surface 7b of the electroformed sleeve 7, and has a width or diameter that varies in the penetrating direction. The first opening end 8a of the molding cavity 8 is on the outer surface 7a of the electroformed sleeve 7, and the second opening end 8b of the molding cavity 8 is on the inner surface 7b of the electroformed sleeve 7. The molding cavity 8 has a stem molding space with a constant opening diameter that penetrates between the outer surface 7a and the inner surface 7b of the electroformed sleeve 7, and a claw molding space that is spatially connected to the stem molding space at the second opening end 8b. Due to the communication of the claw molding spaces, the diameter or maximum diameter of the second opening end 8b is larger than the diameter or maximum diameter of the first opening end 8a. In particular, the stem molding space described above allows the stem portion 61 of the engaging element 42 of the hook-and-loop fastener 40 to be molded in a more upright shape, thereby enhancing the flexibility of the engaging element 42. Also, since the resin typically flows smoothly into the molding cavity 8 through the first opening end 8a rather than the second opening end 8b, problems such as insufficient filling of the molding cavity 8 are unlikely to occur.

[0054] FIG. 11 also illustrates a grinder 210 that grinds the outer surface 7a of the electroformed sleeve 7. As described above, in the electroforming process, the electroformed sleeve 7 tends to be formed thicker in the vicinity of the sacrificial portion 3. If the outer surface 7a of the electroformed sleeve 7 is an unevenly curved surface (uneven surface), the main surface of the base layer 41 of the hook-and-loop fastener 40 also becomes uneven. In order to avoid or suppress such a situation, it is desirable to grind the uneven surface of the surface of the electroformed sleeve 7 with a grinder 210 as shown diagrammatically in FIG. 12. The grinder 210 has, for example, a grinding roll that can rotate at a predetermined position. During the operation of the grinder 210, the electroformed sleeve 7 is rotated to grind and flatten the uneven surface of the electroformed sleeve 7. Manual grinding using abrasive paper can also be employed additionally or alternatively.

[0055] A method for manufacturing a hook-and-loop fastener using the hook-and-loop fastener molding die manufactured by the above-mentioned method will be described with reference to Fig. 12. As shown in Fig. 12, the manufacturing apparatus for the hook-and-loop fastener includes an extruder 21, a rotating machine 28 to which a die wheel (hook-and-loop fastener molding die) 9 having a group of molding cavities 8 formed in an electroformed sleeve 7 is attached, feed rolls 22 and 23, pressure rolls 24 and 25, and an extension section 26.

[0056] The molten or softened material (e.g., synthetic resin) extruded from the extruder 21 is supplied to the peripheral surface 9a (the outer surface 7a of the electroformed sleeve 7) of the die wheel 9 rotated by the rotary machine 28, and is filled into the molding cavity 8 of the die wheel 9 (through its first open end 8a). The second open end 8b of the molding cavity 8 is closed by being attached to the rotary machine 28. The thickness of the base layer 41 of the hook-and-loop fastener 40 is determined by the distance between the extruder 21 and the peripheral surface 9a of the die wheel 9. The hook-and-loop fastener 40 molded by the die wheel 9 is pulled by the feed rolls 22, 23 and released from the die wheel 9. At this time, the resin filled in the molding cavity 8 has hardened to an extent that it can retain its shape (e.g., by partial immersion in the cooling liquid of the cooling tank 27). Therefore, the engaging element 42 of the hook-and-loop fastener 40 is pulled out of the molding cavity 8 with the shape corresponding to the molding space of the molding cavity 8. The arrangement density of the engaging elements 42 at this time is 150 pieces / cm 2 ~400 pieces / cm 2 Within the range of 200 pieces / cm 2 ~300 pieces / cm 2 It could be.

[0057] Description will be given with reference to Figures 13 and 14. The engaging element 42, which is pulled by the feed rolls 22, 23 and released from the die wheel 9, has a stem portion 61 corresponding to the stem portion 31 of the sacrificial portion 3, and claw portions 62, 63 corresponding to the claw portions 32, 33 of the sacrificial portion 3. The stem portion 61 is typically lower than the stem portion 31. This is because the top portion 31t of the stem portion 31 is not embedded in the electroformed sleeve 7. On the other hand, the shape of the claw portions 62, 63 may be the same as that of the claw portions 32, 33.

[0058] The stem portion 61 stands upright on the main surface of the base layer 41. The side surface 61a of the stem portion 61 stands perpendicular to the upper surface of the base layer 41, and therefore the width or diameter W61 of the stem portion 61 is substantially constant along the center line CL of the engaging element 42. Substantially constant means that all the widths or diameters at different positions along the center line CL are within 5% above or below the average value.

[0059] The claws 62, 63 of the engagement element 42, which is pulled by the feed rolls 22, 23 and released from the die wheel 9, protrude radially outward from the upper end of the stem portion 61, and optionally have a thickness gradually decreasing toward the tip. The claws 62, 63 have engagement surfaces 62a, 63a on the base layer 41 side and opposite surfaces 62b, 63b on the opposite side. The engagement surfaces 62a, 63a curve away from the base layer 41 as they move radially outward from the stem portion 61. This may correspond to the shape of the material particles dropped onto the metal sleeve 4 by the 3D printer head 1. The minimum value of the angle between the center line CL of the engagement element 42 and the tangent L1 of the engagement surfaces 62a, 63a may be within a range of, for example, 30° to 70°. In addition, all surfaces of the engagement surfaces 62a, 63a facing the opposite surfaces 62b, 63b are formed in an arc shape. This may be a consequence of forming the moulding cavity 8 using a sacrificial portion 3 formed by the dropping of material particles by the 3D printer head 1 .

[0060] The opposite surfaces 62b, 63b are typically flat surfaces and oriented parallel to the main surface of the base layer 41. The opposite surfaces 62b, 63b are joined to the top surface 61b of the stem portion 61 to form the top surface 64 of the engaging element 42. The flatness of the top surface 64 may correspond to the support surface 4a of the metal sleeve 4. There is a space SP1 between the claw portions 62, 63 and the base layer 41, which gradually increases with increasing distance from the stem portion 61. The female loops of the hook-and-loop fastener can be engaged with the claw portions 62, 63, but secondary and / or tertiary molding can also be performed as described below to improve the performance or commercial value of the hook-and-loop fastener 40.

[0061] Returning to FIG. 12, the hook-and-loop fastener 40 released from the die wheel 9 is subjected to secondary molding by the pressure rolls 24, 25, and then to tertiary molding by the stretching section 26. The hook-and-loop fastener 40 released from the die wheel 9 is sometimes called a primary molded product. The shape of the engaging elements 42 of the hook-and-loop fastener 40 changes due to the secondary molding (the base layer 41 remains unchanged). The base layer 41 is stretched and becomes thinner due to the tertiary molding (the shape of the engaging elements 42 can change as the base layer 41 is stretched). The arrangement density of the engaging elements after the tertiary molding is 150 pcs / cm.2 ~400 pieces / cm 2 In the case of 200% elongation in the tertiary molding, the arrangement density of the engaging elements before the tertiary molding can be within a range of 300 pieces / cm 2 ~800 pieces / cm 2 In addition, when the tertiary molding is performed by stretching the engaging elements by 150%, the arrangement density of the engaging elements before the tertiary molding can be set to 225 pieces / cm. 2 ~600 pieces / cm 2 It can be.

[0062] The pressure rolls 24, 25 press the primary molded product of the hook-and-loop fastener 40 in its thickness direction, and the top of the stem portion 61 of the engaging element 42 is pushed outward in the radial direction. The top of the stem portion 61 spreads outward in the radial direction of the center line CL of the engaging element 42 to form a disk-shaped engaging head. The claw portions 62, 63 protrude further outward in the radial direction of the center line CL from this disk-shaped engaging head. That is, the engaging element 42 after the secondary molding has two types of engaging portions, the engaging head and the claw portion, which are different in position and size, and this improves the engaging performance of the engaging element 42. At this time, the claw portions 62, 63 may hang down so that their tips face the base layer 41. In addition, by adjusting the degree of crushing by the pressure rolls 24, 25, it is also possible to obtain a hook-and-loop fastener 40 having the claw portions 62, 63 that hang down from the peripheral surface of the top of the stem portion 61 toward the base layer 41 without forming a disk-shaped engaging head.

[0063] The stretching section 26 operates to stretch the primary molded product or the secondary molded product of the hook-and-loop fastener 40 in its longitudinal direction. For this purpose, a plurality of rolls with different rotation speeds can be used. For example, a roll with a relatively high rotation speed is arranged downstream in the conveying direction of the hook-and-loop fastener 40, and the hook-and-loop fastener 40 is stretched according to the difference in rotation speed between the rolls. The base layer 41 of the hook-and-loop fastener 40 is stretched, the thickness is reduced, and the density of the engaging elements 42 in the hook-and-loop fastener 40 is reduced. There is a market demand for a thin hook-and-loop fastener with a low density of engaging elements for use as a fastening tape for a diaper (i.e., a hook-and-loop fastener that is gentle on the skin and highly flexible).

[0064] As the base layer 41 of the hook-and-loop fastener 40 is stretched, the stem portion 61 may also deform slightly. For example, the base end of the stem portion 61 connected to the base layer 41 may be slightly wider or have a slightly larger diameter than the tip end of the stem portion 61 to which the claw portions 62, 63 are connected. Therefore, if it is desired to make the diameter of the stem portion 61 uniform in the hook-and-loop fastener 40 after the tertiary molding, it may be possible to form the diameter of the stem portion 31 of the sacrificial portion 3 into a tapered shape toward the top surface 31a.

[0065] Various modifications are possible regarding the positional relationship between the extruder 21 and the die wheel 9. An additional wheel can be provided adjacent to the die wheel 9. Also, the extruder 21 may be disposed in such a manner that the resin is poured between the two wheels.

[0066] As can be seen from a comparison of FIG. 15 and FIG. 16, the 3D shape of the engagement element 42 of the primary molded product is formed based on the 3D shape of the sacrificial part 3. The 3D shape of the engagement element 42 reflects the 3D shape of the sacrificial part 3 (including cases where they do not completely match as described above), and more simply, has an inverted shape thereof. For the shaping of the sacrificial part 3, an appropriate shaping technique can be used, and the sacrificial part 3 can also be shaped into a different or more complex shape. As a result, the engagement element 42 also has a different or more complex shape. FIG. 17 shows, as a mere example, an engagement element 42 in which a total of six claws are connected to the stem part 61. That is, there are a total of four additional claws between the claws 62 and 63. The engagement element 42 of such a shape can be relatively easily shaped based on the shaping of the sacrificial part 3.

[0067] Working Example An electroforming mold was manufactured using the device shown in FIG. 2. The resist discharged from the 3D printer head was semi-cured with ultraviolet light to form a sacrificial part, and finally, a group of sacrificial parts was irradiated with ultraviolet light to further promote curing. Next, a nickel electroforming process was performed to form an electroformed sleeve made of nickel in which the sacrificial part was embedded. Next, the electroformed sleeve was immersed in an organic solvent (N-methyl-2-pyrrolidone) to swell and remove the sacrificial part. Next, a hook-and-loop fastener was manufactured using the device shown in FIG. 12. FIG. 18 is a photograph of the top surface of the hook-and-loop fastener. FIG. 19 is a photograph of the side surface of the hook-and-loop fastener. In this way, the engaging elements are properly molded, there is no variation in the connecting position of the claw part relative to the stem part (constant in a group of engaging elements), and the stem part is upright with approximately the same diameter. Note that FIGS. 18 and 19 show photographs of a hook-and-loop fastener that has not been subjected to the above-mentioned secondary and tertiary molding.

[0068] The electroforming mold was manufactured so that the sacrificial parts 3 were arranged in a lattice pattern with a pitch of 0.7 mm in the width direction and a pitch of 0.3 mm in the circumferential direction. The electroformed sleeve manufactured in this way had through holes formed in a lattice pattern with a pitch of 0.7 mm in the width direction and a pitch of 0.3 mm in the circumferential direction. The primary molded product of the hook-and-loop fastener manufactured using this electroformed sleeve had a base layer 41 with a thickness of 0.08 mm. The primary molded product was stretched 200% in the machine direction (in the circumferential direction of the electroformed sleeve) as a tertiary molding after the secondary molding, and the hook-and-loop fastener after the tertiary molding had a base layer 41 with a thickness of 0.04 mm. The engaging elements 42 were arranged on the base layer 41 with a pitch of 0.6 mm in the width direction and a pitch of 0.6 mm in the circumferential direction. Due to the stretching in the machine direction in the tertiary molding, the hook-and-loop fastener has molecular orientation mainly in the stretching direction in the base layer 41.

[0069] The advantages of the present disclosure will be explained in comparison with Patent Document 1. Among those disclosed in Patent Document 1, a die wheel suitable for mass production is constructed from a combination of inner and outer cylinders as shown in FIG. 37 of the same document, and was actually prototyped. FIG. 20(a) shows that a groove 84 is formed in an inner cylinder 82 and a through hole 83 is formed in an outer cylinder 81, and FIG. 20(b) shows a state in which the resin extruded from the extruder is filled in the through hole 83 and a part of the groove 84. The part filled in the through hole 83 becomes a stem portion. The part filled in the groove 84 becomes a claw portion. The stem portion is secondary molded to have an engaging head, but illustration thereof is omitted.

[0070] FIG. 21 shows a process of forming a through hole in a cylinder 81 by an electron beam. The target portion of the cylinder 81 is laminated on a backing material 85, and a hole is formed in the cylinder 81 by an electron beam. When the backing material 85 is irradiated with an electron beam, the constituent material of the backing material 85 scatters, and the opening width increases. The opening width is larger on the side away from the backing material 85. This results in a larger diameter of the stem portion on the base layer side of the hook-and-loop fastener. Due to the expansion of the diameter of the stem portion on the base layer side of the hook-and-loop fastener, there is a limit to narrowing the pitch of the stem portion (arrangement pitch of the through holes). When a thin hook-and-loop fastener is obtained using the extension portion 26 as shown in FIG. 12, the density of the engaging elements is increased at the stage of the primary molded product in order to obtain a desired density of engaging elements after stretching. When the through hole is formed by an electron beam, there is a limit to narrowing the pitch of the stem portion, and a primary molded product that can withstand high-magnification stretching could not be obtained.

[0071] 22 shows that there is variation in the positions of the claws 62', 63' on the engaging head 65 of the engaging element 42' due to misalignment between the inner and outer cylinders. The manufacturing tolerances of the inner cylinder 82 and the outer cylinder 81 are accumulated, and the positions of the claws 62', 63' on the engaging head 65 differ depending on the position of the engaging element 42'. It is difficult to resolve the problem of misalignment due to the accumulation of tolerances in a relatively large mold for molding a hook-and-loop fastener. Furthermore, variation in the positions of the claws 62', 63' on the engaging head 65 of the engaging element 42' can cause variation in the engagement strength with the loop member and the feel depending on the part of the hook-and-loop fastener.

[0072] According to the method and apparatus of the present disclosure, the technical problems described with respect to Figures 21 and 22 are solved or at least the occurrence of the problems is suppressed.

[0073] In light of the above disclosure, those skilled in the art can make various modifications to each feature and each embodiment. The reference symbols included in the claims are for reference only and should not be used to limit the interpretation of the claims. [Explanation of symbols]

[0074] 1: 3D printer head 3: Sacrificial part 4: Metal sleeve 4a: Support surface 6: Electroforming mold 7: Electroformed sleeve 8: Molding cavity 40: Hook and loop fastener

Claims

1. A method for manufacturing a hook-and-loop fastener molding die (9), comprising the steps of: An electroforming film (7) is formed on an electroforming mold (6) having a group of electrically insulating sacrificial portions (3) formed on a support surface (4a) of a conductive support material (4), and the electroforming film (7) is formed on the support surface (4a) of the support material (4), and each of the sacrificial portions (3) of the group of sacrificial portions (3) is at least partially embedded in the electroforming film (7); The method for manufacturing a hook-and-loop fastener molding die includes removing the group of sacrificial portions (3) of the electroforming die (6) to obtain a hook-and-loop fastener molding die (9) in which a group of molding cavities (8) corresponding to the group of sacrificial portions (3) are formed in the electroforming film (7).

2. The method further comprises manufacturing the electroforming mold (6), The method for manufacturing a die for molding a hook-and-loop fastener according to claim 1, wherein manufacturing the electroforming die (6) includes forming the group of sacrificial portions (3) on a support surface (4a) of the support material (4).

3. The method for manufacturing a hook-and-loop fastener molding die according to claim 2, wherein forming the group of sacrificial portions (3) on the support surface (4a) of the support material (4) includes a 3D printer head (1) forming the group of sacrificial portions (3) on the support surface (4a) of the support material (4) based on the ejection of a light or thermosetting material.

4. Building the group of sacrificial portions (3) on the support surface (4a) of the support material (4) includes the 3D printer head (1) building a first subset of the group of sacrificial portions (3) in a first region of the support surface (4a) and, subsequent to building the first subset, building a second subset of the group of sacrificial portions (3) in a second region of the support surface (4a) adjacent to the first region; 4. The method for manufacturing a hook-and-loop fastener molding die according to claim 3, wherein the plurality of sacrificial portions (3) included in the first subset and the plurality of sacrificial portions (3) included in the second subset are complementarily arranged so as to draw a non-linear boundary line between the first and second regions.

5. The method for manufacturing a mold for molding a hook-and-loop fastener according to claim 3, wherein the 3D printer head (1) is operable so that the light or thermosetting materials ejected at different times merge in the air and land on the support surface (4a).

6. 4. A method for manufacturing a die for molding a hook-and-loop fastener according to claim 3, wherein the support material (4) is a flexible metal sleeve, and the 3D printer head (1) forms the group of sacrificial portions (3) on a flat surface of the support surface (4a) formed by deformation of the metal sleeve.

7. The method for manufacturing a die for molding a hook-and-loop fastener according to any one of claims 1 to 6, wherein the electroformed film (7) is formed as an electroformed sleeve.

8. The method for manufacturing a die for molding a hook-and-loop fastener according to any one of claims 1 to 6, further comprising removing the electroformed film (7) from the support material (4).

9. 7. A method for manufacturing a hook-and-loop fastener molding die (9) according to any one of claims 1 to 6, wherein the electroformed film (7) is formed so as to have an uneven surface on the side away from the support surface (4a), and further comprising polishing the uneven surface of the electroformed film (7).

10. 7. A method for manufacturing a mold for molding a hook-and-loop fastener according to claim 1, wherein each sacrificial portion (3) of the group of sacrificial portions (3) includes a stem portion standing from the support surface (4a) and at least one claw portion connected to the stem portion on the support surface (4a).

11. The manufacturing method of a mold for molding a hook-and-loop fastener according to claim 10, wherein each molding cavity (8) of the group of molding cavities (8) includes a stem molding space having a constant opening diameter formed by the stem portion, and a claw portion molding space formed by one or more claw portions.

12. 7. The method for manufacturing a die for molding a hook-and-loop fastener according to claim 1, wherein each molding cavity (8) of the group of molding cavities (8) penetrates through the electroformed film (7).

13. 6. The method for manufacturing a die for molding a hook-and-loop fastener according to claim 1, wherein the support material (4) is a flexible metal sleeve.

14. A method for manufacturing a hook-and-loop fastener, comprising the steps of: manufacturing a hook-and-loop fastener by using the hook-and-loop fastener molding die (9) according to any one of claims 1 to 6.

15. A hook-and-loop fastener manufactured using the hook-and-loop fastener molding die (9) according to any one of claims 1 to 6.

16. A hook-and-loop fastener comprising a base layer and a group of engaging elements formed on a main surface of the base layer, A hook-and-loop fastener, wherein each engaging element of the group of engaging elements includes a cylindrical stem portion protruding from the base layer and one or more claw portions connected to the top of the stem portion, and the stem portion has a substantially constant diameter in a direction away from the base layer.

17. 17. The hook-and-loop fastener according to claim 16, wherein the connection positions of the one or more claw portions to the tops of the stem portions are consistent and constant in the group of engaging elements.

18. The arrangement density of the engaging elements is 150 pieces / cm 2 ~400 pieces / cm 2 The hook-and-loop fastener according to claim 16 or 17, wherein the thickness is within the range of

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