Method for manufacturing mold for molding hook-and-loop fastener, hook-and-loop fastener, and method for manufacturing same

Abstract

This method for manufacturing a mold (9) for molding a hook-and-loop fastener comprises: forming an electroforming sleeve (7) on an electroforming mold (6) in which a group of sacrificial parts (3) having electrical insulation properties are formed on a support surface (4a) of a metal sleeve (4), thereby forming the electroforming sleeve (7) on the support surface (4a) of the metal sleeve (4), and at least partially embedding each sacrificial part (3) of the group of sacrificial parts (3) in the electroforming sleeve (7); and removing the group of sacrificial parts (3) of the electroforming mold (6) to obtain the mold (9) for molding a hook-and-loop fastener in which a group of molding cavities (8) corresponding to the group of sacrificial parts (3) are formed in the electroforming sleeve (7).

Description

Method for manufacturing a mold for forming a hook-and-loop fastener, and a method for manufacturing the hook-and-loop fastener

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

[0002] Patent Document 1 discloses a hook-and-loop fastener having engaging elements in which claws are protruded from the outer periphery of an engaging head by primary and secondary molding (see, for example, Figure 2 of the document). A cylindrical body having a through hole and a recessed groove, as shown in Figure 8 of the document, is used to mold the hook-and-loop fastener (see also Figure 7 of the document). As shown in Figure 36 of the document, the document also discloses a configuration using a two-layered cylindrical body, an outer and an inner one, and the structure of this configuration is shown in Figure 37 of the document.

[0003] Although unrelated to hook-and-loop fasteners, Patent Document 2 discloses a method for releasing a cylindrical member from a mold. The method involves placing an insulating material on a cylindrical metal mold, forming an electroformed film on the side of the mold so as to include recesses or holes formed by the insulating material, and then releasing the electroformed film from the mold using the recesses or holes (see Figures 1 and 2 in the same document).

[0004] International Publication No. 2017 / 110127 Japanese Patent Application Laid-Open No. 2019-44220

[0005] It was extremely difficult to manufacture the cylindrical body disclosed in Patent Document 1 with high precision. With regard to the configuration shown in Figure 37 of the same document, it was difficult to ensure the alignment of the through-hole of the outer cylindrical body with the groove of the inner cylindrical body, and variations occurred 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 actually manufactured hook-and-loop fasteners, it was possible to observe that the position of the claw with respect to the stem varied depending on the position of the engaging element within the plane of the hook-and-loop fastener, and there was a need to reduce the variation in the shape of the engaging elements of the hook-and-loop fastener.

[0006] As can be seen from the above non-limiting exemplary description, there is a need for new techniques that contribute to improving the shape accuracy of engaging elements of hook-and-loop fasteners.

[0007] A method for 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, so that the electroforming film is formed on the support surface of the support material and each sacrificial part 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 manufacturing a hook-and-loop fastener according to another aspect of the present disclosure uses the above-mentioned hook-and-loop fastener molding die to manufacture the hook-and-loop fastener. This disclosure also relates to the hook-and-loop fastener manufactured thereby.

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

[0010] In some cases, building the group of sacrificial portions on the support surface of the support material includes a 3D printer head building the group of sacrificial portions on the support surface of the support material based on the ejection of a photo- or thermosetting material.

[0011] In some cases, building the group of sacrificial portions on the support surface of the support material includes the 3D printer head building a first subset of the group of sacrificial portions in a first region of the support surface and, subsequent to building the first subset, building a second subset of the group of sacrificial portions in a second region of the support surface adjacent to the first region, wherein the sacrificial portions in the first subset and the sacrificial portions in the second subset are complementary arranged 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 materials dispensed at different times to coalesce in mid-air and land on a support surface.

[0013] In some cases, the support material is a flexible metal sleeve, and the 3D printer head can print a group 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 below the 3D printer head and another position (e.g., a position directly below a UV light source).

[0014] The method for 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 mold can further include polishing the uneven surface of the electroformed film. In some cases, the electroformed film is formed so as to have an uneven surface on the side away from the support surface.

[0016] In some cases, each sacrificial portion of the group of sacrificial portions includes a stem portion upstanding from the support surface and at least one or more prongs 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 fixed opening diameter formed by a stem portion, and a claw molding space formed by one or more claw portions.

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

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

[0020] A hook-and-loop fastener according to yet another aspect of the present disclosure is a hook-and-loop fastener including a base layer and a group of engaging elements formed on a main surface of the base layer. Each engaging element of the group of 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 positions at which the one or more claws are connected 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 / cm to 400 pieces / cm.

[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.

[0023] 1 is a schematic flowchart of a method for manufacturing a mold for molding a hook-and-loop fastener according to one embodiment of the present disclosure. FIG. 2 is a schematic diagram of a manufacturing apparatus for an electroforming mold. FIG. 3 is a schematic side view of a sacrificial part. FIG. 4 is a schematic top view of a sacrificial part. FIG. 5 is a schematic diagram showing a process for molding a sacrificial part. FIG. 6 is a schematic diagram showing the continuous formation of subsets of molded parts in adjacent regions of a metal sleeve. FIG. 7 is a schematic diagram of an electroforming mold. FIG. 8 is a schematic process diagram showing an electroforming process. FIG. 9 is a schematic diagram showing an electroformed sleeve with a sacrificial part obtained by the electroforming process. FIG. 10 is a process diagram for removing a sacrificial part. FIG. 11 is a schematic diagram showing an electroformed sleeve from which a sacrificial part has been removed, and also showing a polishing machine for polishing the outer surface of the electroformed sleeve. FIG. 12 is a schematic diagram of a hook-and-loop fastener manufacturing apparatus. FIG. 13 is a schematic partial cross-sectional view of a hook-and-loop fastener. FIG. 14 is a schematic perspective view of an engaging element of the hook-and-loop fastener. FIG. 15 is a schematic perspective view of a sacrificial part molded on a metal sleeve. FIG. 16 is a schematic perspective view of an engaging element rising from a base layer of the hook-and-loop fastener. FIG. 17 is a schematic perspective view showing a modified example of the engaging element. FIG. 18 is a photograph of the top surface of a hook-and-loop fastener according to an example. FIG. 19 is a photograph of the side of a hook-and-loop fastener according to an example. 1A and 1B are schematic diagrams showing the construction of a die wheel from an inner cylinder and an outer cylinder, a schematic diagram showing the drilling of holes in the outer cylinder by an electron beam, and a schematic diagram showing the variation in the position of the claws in the engaging elements.

[0024] Non-limiting embodiments and features of the present invention will be described below with reference to the drawings. Those skilled in the art will be able to combine the embodiments and / or features without excessive explanation and will be able to understand the synergistic effects of such combinations. Duplicate descriptions between embodiments will be omitted as a general rule. The reference drawings are primarily intended to describe the invention and are simplified for convenience of drawing.

[0025] A method for manufacturing a hook-and-loop fastener molding die will be described below. An exemplary manufacturing method includes, as shown in FIG. 1 , manufacturing an electroforming die containing a group of sacrificial portions (S1), using the electroforming die to perform an electroforming process (S2), and then removing the group of sacrificial portions from the electroforming die (S3). Individual sacrificial portions are formed using an appropriate molding method (e.g., 3D (three-dimensional) molding technology, injection molding, or photolithography), and then removed (typically by chemical treatment) after the electroforming process, resulting in an electroformed film having individual molding cavities corresponding to the individual sacrificial portions. By using this electroformed film as a hook-and-loop fastener molding die, a hook-and-loop fastener having a group of engaging elements formed therein with high shape / dimensional uniformity can be manufactured. The sacrificial portions are made of any electrically insulating material suitable for molding.

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

[0027] While this specification primarily discusses utilizing 3D fabrication techniques, such as a 3D printer head, to fabricate the group of sacrificial portions, it should be noted that other methods (e.g., injection molding, photolithography) may also be used.

[0028] The electroforming mold manufacturing apparatus 100 includes a 3D printer head 1, a UV light source 2, and a transport mechanism. The 3D printer head 1 forms a group of sacrificial portions 3 on the support surface 4a of the metal sleeve 4 by discharging a photocurable material. The 3D printer head 1 may have, for example, a group of nozzles arranged two-dimensionally and be capable of discharging the photocurable material from one or more selected nozzles. This allows for the formation of subsets of sacrificial portions 3 within a two-dimensional area. The specific structure and mechanism of the 3D printer head 1 are not particularly limited, and various types of 3D printer heads can be used. For example, a 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). Naturally, a thermosetting material can be used instead of a photocurable material. In this case, a heat source (e.g., 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 either built into the 3D printer head 1 or provided independently. UV-curable resin (e.g., resist) ejected from the nozzles of the 3D printer head 1 is cured (typically semi-cured) by 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 regarding the timing of material ejection from the 3D printer head 1 and the timing of UV light emission.

[0030] The transport mechanism may include 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 movement in a certain transport direction (e.g., 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 without the sacrificial part 3 can be supplied to a position directly below the 3D printer head 1, and similarly, the support surface 4a with the sacrificial part 3 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 with its support surface 4a extending flat between two rolls 5a, 5b. Deformation of the metal sleeve 4 forms a flat surface on the support surface 4a, and the 3D printer head 1 prints a group of sacrificial parts 3 on the flat surface. A general-purpose 3D printer head 1 can be used to print a group of sacrificial parts 3, avoiding the need to specially design the 3D printer head 1 for printing sacrificial parts 3 on a curved surface. The 3D printer head 1 and the UV light source 2 can also be movable relative to the conveyor 5.

[0032] The metal sleeve 4 is a hollow cylinder having an outer support surface 4a 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, in the range of 0.05 mm to 0.3 mm, preferably in the range of 0.1 mm to 0.2 mm. A support material other than the metal sleeve, such as a metal plate, can also be used to support the sacrificial portion 3.

[0033] As will be described later, the 3D printer head 1 has different regions (e.g., Q N , Q N-1 , Q N-2(N is a natural number equal to or greater than 2)), a subset of sacrificial portions 3 can be formed. When N=3, exemplarily, the metal sleeve 4 is first placed on the conveyor 5 so that the first region Q1 of the support surface 4a is flat between the two rolls 5a and 5b. The stage is then moved to move the support surface 4a in 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 portions 3 on the support surface 4a in the first region Q1. Next, the metal sleeve 4 is placed on the conveyor 5 so that the second region Q2 of the support surface 4a is flat between the two rolls 5a and 5b as the two rolls 5a and 5b rotate. As with the first region, a desired number of sacrificial portions 3 are also formed on the support surface 4a in the second region. A similar procedure is used to form sacrificial portions 3 in the third region.

[0034] The maximum number of sacrificial parts 3 that the 3D printer head 1 can form 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 the possibility in mind that an engaging element temporarily molded by a hook-and-loop fastener molding die may be 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 its center line CL and a width or diameter direction that is perpendicular to the height direction. The sacrificial portion 3 has a width or diameter that varies in the height direction, which is reflected in the shape of the molding cavity and the engaging element (or a precursor of the engaging element).

[0037] Exemplary, the sacrificial portion 3 includes a substantially cylindrical stem portion 31 that stands upright from the support surface 4a of the metal sleeve 4, and at least one or more claw portions 32, 33 that are 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 that approaches 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 the edge 31c may be the result of the stem portion 31 being formed by dropping material particles using the 3D printer head 1. Note that, in relation to the stem portion 31, the claw portion may also be called a "radial protrusion."

[0039] Although the detailed 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 within a range of 0.3 to 0.8 mm, and more preferably within a range of 0.4 to 0.6 mm. The second height H2 may be within a range of 0.01 to 0.06 mm, and more preferably within a 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, of the portion where the claw portions 32, 33 are connected to the stem portion 31. The first width or diameter W1 may be within a range of 100 μm to 200 μm, and preferably within a 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 claws 32, 33 from the circumferential surface of the stem portion 31 may be about 25% to 50% of the diameter of the stem portion 31.

[0040] A case in which a 3D printer head 1 is used to form a sacrificial portion 3 will be described with reference to FIGS. 5 and 6 . As shown in FIG. 5( a), material particles (of a photocurable material) ejected from the nozzle of the 3D printer head 1 land on the support surface 4 a of the metal sleeve 4, forming claws 32. At the same or different timing as the ejection of the material particles from FIG. 5( a), material particles are ejected from the nozzle of the 3D printer head 1 and land on the support surface 4 a of the metal sleeve 4, forming claws 33, as shown in FIG. 5( b). The area of ​​the support surface 4 a where the sacrificial portion 3 is to be formed is positioned directly below the 3D printer head 1, and after the material particles land as shown in FIGS. 5( a) and 5( b), the stage is moved to move the area directly below the UV light source 2, as described below, and the material particles are UV-cured. This procedure can be repeated to stack the material particles vertically until the claws 33 reach the desired height H2.

[0041] Simultaneously with or after the ejection of the material particles shown in FIGS. 5( a) and 5(b), a series of material particles are ejected from the 3D printer head 1 at different times, as shown in FIG. 5(c), which then coalesce in a chain reaction in midair and land on the support surface 4a of the metal sleeve 4 to form stem portions 31. By causing the material particles to coalesce in a chain reaction in midair, large droplets of material particles can be obtained even with a small nozzle. Therefore, even if a narrow pitch of the stem portions 31 is desired (when the nozzle diameter cannot be increased), the stem portions 31 can be made to the desired thickness. After the series of material particles coalesce in midair and land on the support surface 4a, the stage is moved to move the region directly below the UV light source 2, similar to the claw portion 33, and the material particles are UV-cured. This procedure can be repeated to stack the material particles vertically until the stem portions 31 reach the desired height H1. Furthermore, by forming a thick stem portion 31 by combining material particles in a chain reaction in the air, it is possible to form claw portions 33 that are relatively small compared to the diameter of the stem portion 31. By having small claw portions 33, sufficient engagement strength can be obtained when the basis weight of the female member (loop or nonwoven fabric) that engages with the hook-and-loop fastener is small.

[0042] 5(a) to 5(c), the material particles are exposed to UV light and semi-cured while falling toward or after landing on the support surface 4a of the metal sleeve 4. Additionally or alternatively, after the entire sacrificial portion 3 shown in FIG. 5(c) is formed, a curing process is performed to further promote curing of the sacrificial portion 3. The width or diameter of the stem portion 31 can also be fine-tuned by adjusting the intensity 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 ejection conditions of the material particles from the 3D printer head 1.

[0043] The 3D printer head 1 has different regions (e.g., Q N , Q N-1 , Q N-2 (N is a natural number equal to or greater than 2)), a subset of sacrificial portions 3 may be formed for each region Q1 (Q1). Referring 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, followed by a second subset of 24 sacrificial portions 3 in the second region Q2, and then a third subset of 24 sacrificial portions 3 in the third region Q3. The 24 sacrificial portions 3 in the first region Q1 and the 24 sacrificial portions 3 in the second region Q2 are arranged complementarily (in a complementary zigzag pattern in the illustrated example) so that a non-linear boundary line can be drawn between the first region Q1 and the second region Q2. Similarly, the 24 sacrificial portions 3 in the second region Q2 and the 24 sacrificial portions 3 in the third region Q3 are arranged complementarily (in a complementary zigzag pattern in the illustrated example) 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 different numbers of sacrificial portions can be formed in different regions. The non-linear boundary line is not limited to a zigzag line, but may be a bumpy line. Each sacrificial portion 3 can be addressed using 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 target density of the engaging elements of the 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 multiple regions, there is little difference in the density of the sacrificial portions 3 in each region; for example, compared to the region with the highest density, the densities of all other regions are within a range between 0.95 times the maximum density and 1.05 times the maximum density.

[0045] By making the metal sleeve 4 sufficiently thin and flexible, it can be removed from the rolls 5a and 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 the metal sleeve 4 due to external force or deformation of the metal sleeve 4. Therefore, it is desirable to handle the metal sleeve 4 carefully to prevent the sacrificial portion 3 from falling off. The metal sleeve 4 can also be temporarily fixed to the rolls 5a and 5b using a double-sided seal or mechanical fasteners (e.g., screws, bolts).

[0046] The electroforming mold 6 shown in Figure 7 is manufactured using the above-described method or another method different from the above. While the metal sleeve 4 of the electroforming mold 6 can be reused, the group of sacrificial parts 3 cannot be reused. Therefore, it is practical to efficiently manufacture the group of sacrificial parts 3 by combining the above-described 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 mold 6. An appropriate electrolyte 52 is stored in an electroforming tank 51, and the electroforming mold 6 is immersed in the liquid. During the limited time the electroforming mold 6 is immersed in the electrolyte, the sacrificial portion 3 of the electroforming mold 6 is not dissolved by the electrolyte. The metal sleeve 4 of the electroforming mold 6 is connected to the cathode of a DC power supply, and a soluble or insoluble electrode (e.g., a nickel metal bar) 53 serving as a metal ion source is connected to the anode of the DC power supply. The nickel metal bar can also be placed in a conductive mesh cage, which 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 mold 6 and deposit on the support surface 4a of the metal sleeve 4. In this manner, an 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. Metals other than nickel (e.g., 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 in the electroforming mold 6 can 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 becoming narrower in diameter or width due to the edge 31c of the stem portion 31. Although this increases the burden or cost, even if the entire sacrificial portion 3 is embedded in the electroformed sleeve 7, it is possible to form a molding cavity that penetrates the electroformed sleeve 7 by grinding the surface of the electroformed sleeve 7.

[0049] 9 schematically shows the electroformed sleeve 7 removed from the metal sleeve 4, i.e., a semi-finished product of the hook-and-loop fastener molding die. 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 of 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. If 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 two-dimensionally on each surface of the electroformed sleeve 7. The inner surface 7b may be a smooth, curved surface without irregularities. The outer surface 7a may be a curved surface with irregularities (convex and concave surfaces) 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 thick near the sacrificial portion 3. From this perspective, it is advisable to intentionally make the height of the sacrificial portion 3 high, and for this reason, it is also desirable that the top portion 31t of the stem portion 31 is not embedded in the electroformed sleeve 7. For convenience of drawing, variations in the thickness of the electroformed sleeve 7 are not explicitly shown.

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

[0053] 11 shows an electroformed sleeve 7 with the sacrificial portion 3 removed, i.e., a mold for molding a hook-and-loop fastener. The molding cavity 8 penetrates the electroformed sleeve 7 between its outer surface 7a and inner surface 7b and has a width or diameter that varies in the direction of penetration. The first open end 8a of the molding cavity 8 is located on the outer surface 7a of the electroformed sleeve 7, and the second open end 8b of the molding cavity 8 is located 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 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 open end 8b. Due to the communication between the claw molding spaces, the diameter or maximum diameter of the second open end 8b is larger than the diameter or maximum diameter of the first open 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 increasing the flexibility of the engaging element 42. Furthermore, 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 less likely to occur.

[0054] FIG. 11 also illustrates a polishing machine 210 that polishes the outer surface 7 a of the electroformed sleeve 7. As described above, the electroforming process tends to thicken the electroformed sleeve 7 near the sacrificial portion 3. If the outer surface 7 a 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 will also be uneven. To avoid or suppress this situation, it is desirable to polish the uneven surface of the electroformed sleeve 7 using a polishing machine 210, as schematically shown in FIG. 12. The polishing machine 210 has, for example, a polishing roll that can rotate at a predetermined position. The electroformed sleeve 7 is rotated while the polishing machine 210 is operating, and the uneven surface of the electroformed sleeve 7 is polished and flattened. Manual polishing using abrasive paper can also be used 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-described method will be described with reference to Fig. 12. As shown in Fig. 12, the apparatus for manufacturing a hook-and-loop fastener includes an extruder 21, a rotating machine 28 to which is attached a die wheel (hook-and-loop fastener molding die) 9 having a group of molding cavities 8 formed in an electroformed sleeve 7, 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 (outer surface 7a of the electroformed sleeve 7) of the die wheel 9, which is rotated by the rotary machine 28, and fills 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 and 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 in the cooling tank 27). Therefore, the engaging elements 42 of the hook-and-loop fastener 40 are successfully pulled out of the molding cavity 8 while retaining 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 / cm2 ~400 pieces / cm 2 in the range of 200 / cm 2 ~300 pieces / cm 2 It could be.

[0057] 13 and 14 will be described. The engaging element 42, which has been pulled by the feed rolls 22 and 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 and 63 corresponding to the claw portions 32 and 33 of the sacrificial portion 3. The stem portion 61 is typically lower than the stem portion 31 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 and 63 may be the same as that of the claw portions 32 and 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. Being 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 engaging 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 taper in thickness toward the tip. The claws 62, 63 have engaging surfaces 62a, 63a facing the base layer 41 and opposite surfaces 62b, 63b. The engaging surfaces 62a, 63a curve away from the base layer 41 as they move radially outward from the stem portion 61. This curve may correspond to the shape of the material particles dropped onto the metal sleeve 4 by the 3D printer head 1. The minimum angle between the center line CL of the engaging element 42 and the tangent line L1 of the engaging surfaces 62a, 63a may be, for example, within a range of 30° to 70°. Furthermore, all surfaces of the engaging 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 part 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 a 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 Figure 12, the hook-and-loop fastener 40 released from the die wheel 9 is subjected to secondary molding by the pressure rolls 24 and 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 secondary molding (the base layer 41 remains unchanged). The base layer 41 is stretched and becomes thinner due to 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 tertiary molding is 150 pieces / cm 2 ~400 pieces / cm 2 In the tertiary molding, when the stretching is 200%, the arrangement density of the engaging elements before the tertiary molding can be within the range of 300 pieces / cm 2 ~800 pieces / cm 2 In addition, when the tertiary molding is performed by stretching the sheet 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 made into.

[0062] The pressure rolls 24, 25 pressurize the primary molded product of the hook-and-loop fastener 40 in its thickness direction, thereby expanding the tops of the stem portions 61 of the engaging elements 42 radially outward. The tops of the stem portions 61 expand radially outward from the center line CL of the engaging elements 42, forming disk-shaped engaging heads. The claw portions 62, 63 protrude further radially outward from the disk-shaped engaging heads. In other words, the engaging elements 42 after secondary molding have two types of engaging portions, the engaging heads and the claw portions, which differ in position and size, thereby improving the engaging performance of the engaging elements 42. In this case, the claw portions 62, 63 may hang downward so that their tips face the base layer 41. Furthermore, by adjusting the degree of compression by the pressure rolls 24, 25, it is possible to obtain a hook-and-loop fastener 40 having claw portions 62, 63 that hang downward from the peripheral surface of the tops of the stem portions 61 toward the base layer 41, without forming disk-shaped engaging heads.

[0063] The stretching section 26 operates to stretch the primary or secondary molded product of the hook-and-loop fastener 40 in its longitudinal direction. For this purpose, a plurality of rolls with different rotational speeds can be used. For example, a roll with a relatively high rotational speed is disposed downstream in the conveyance direction of the hook-and-loop fastener 40, and the hook-and-loop fastener 40 is stretched in accordance with the difference in rotational speed between the rolls. The base layer 41 of the hook-and-loop fastener 40 is stretched, reducing its thickness and decreasing the density of the engaging elements 42 in the hook-and-loop fastener 40. 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 diapers (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 larger diameter than the tip end of the stem portion 61 where 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 tertiary molding, it may be possible to form the diameter of the stem portion 31 of the sacrificial portion 3 in a tapered shape toward the top surface 31a.

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

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

[0067] Example: An electroforming mold was manufactured using the apparatus shown in Figure 2. Resist ejected from a 3D printer head was semi-cured with ultraviolet light to form sacrificial portions. Finally, a group of sacrificial portions was irradiated with ultraviolet light to further promote curing. Subsequently, a nickel electroforming process was performed to form an electroformed sleeve made of nickel with embedded sacrificial portions. The electroformed sleeve was then immersed in an organic solvent (N-methyl-2-pyrrolidone) to swell and remove the sacrificial portions. Next, a hook-and-loop fastener was manufactured using the apparatus shown in Figure 12. Figure 18 is a photograph of the top surface of the hook-and-loop fastener. Figure 19 is a photograph of the side surface of the hook-and-loop fastener. As shown, the engaging elements were properly molded, there was no variation in the connection position of the claw portion relative to the stem portion (consistent across a group of engaging elements), and the stem portion was upright with approximately the same diameter. Note that Figures 18 and 19 show photographs of a hook-and-loop fastener that had not undergone the above-mentioned secondary and tertiary molding.

[0068] The electroforming mold was manufactured so that the sacrificial portions 3 were arranged in a grid pattern with a widthwise pitch of 0.7 mm and a circumferential pitch of 0.3 mm. The electroformed sleeve manufactured using this mold had through holes arranged in a grid pattern with a widthwise pitch of 0.7 mm and a circumferential pitch of 0.3 mm. The primary molded hook-and-loop fastener manufactured using this electroformed sleeve had a base layer 41 with a thickness of 0.08 mm. After secondary molding, the primary molded article was stretched 200% in the machine direction (circumferential direction of the electroformed sleeve) as a tertiary molding. The hook-and-loop fastener after 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 widthwise pitch of 0.6 mm and a circumferential pitch of 0.6 mm. Due to the stretching in the machine direction during tertiary molding, the hook-and-loop fastener had molecular orientation mainly in the stretched direction of the base layer 41.

[0069] The advantages of the present disclosure will be explained in comparison with Patent Document 1. Among the die wheels 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 Figure 37 of the same document, and a prototype of this was actually produced. Figure 20(a) shows a groove 84 formed in an inner cylinder 82 and a through-hole 83 formed in an outer cylinder 81, and Figure 20(b) shows a state in which resin extruded from an extruder has filled the through-hole 83 and part of the groove 84. The portion filled in the through-hole 83 becomes the stem portion. The portion filled in the groove 84 becomes the claw portion. The stem portion is secondary molded to have an engaging head, but this is not shown in the figure.

[0070] FIG. 21 shows the process of forming through holes in a cylindrical body 81 using an electron beam. The target portion of the cylindrical body 81 is layered on a backing material 85, and holes are formed in the cylindrical body 81 using the electron beam. When the electron beam is irradiated onto the backing material 85, the constituent materials of the backing material 85 are scattered, increasing the opening width. The opening width is larger on the side farther from the backing material 85. This results in an increase in the diameter of the stem portion on the base layer side of the hook-and-loop fastener. The expansion of the diameter of the stem portion on the base layer side of the hook-and-loop fastener limits the narrowing of the stem portion pitch (the arrangement pitch of the through holes). When a thin hook-and-loop fastener is obtained using the extension portion 26 shown in FIG. 12, the density of the engaging elements is increased in the primary molded product to achieve the desired engaging element density after stretching. When forming through holes using an electron beam, there is a limit to the narrowing of the stem portion pitch, making it impossible to obtain a primary molded product that can withstand high stretching ratios.

[0071] 22 shows that misalignment between the inner and outer cylinders causes variations in the positions of the claws 62', 63' on the engaging head 65 of the engaging element 42'. The manufacturing tolerances of the inner cylinder 82 and the outer cylinder 81 accumulate, causing the positions of the claws 62', 63' relative to the engaging head 65 to differ depending on the position of the engaging element 42'. It is difficult to resolve the problem of misalignment due to tolerance accumulation in a relatively large mold for molding a hook-and-loop fastener. Furthermore, variations in the positions of the claws 62', 63' on the engaging head 65 of the engaging element 42' can cause variations 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 reference 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 numerals included in the claims are for reference purposes only and should not be used to limit the interpretation of the claims.

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

Claims

1. A method for manufacturing a hook-and-loop fastener molding die (9), comprising forming an electroformed film (7) on an electroforming die (6) having a group of electrically insulating sacrificial portions (3) formed on a support surface (4a) of a conductive support material (4), such that the electroformed film (7) is formed on the support surface (4a) of the support material (4) and each of the group of sacrificial portions (3) is at least partially embedded in the electroformed film (7), and removing the group of sacrificial portions (3) from the electroforming die (6) to obtain a hook-and-loop fastener molding die (9) having a group of molding cavities (8) formed in the electroformed film (7) corresponding to the group of sacrificial portions (3).

2. A method for manufacturing a hook-and-loop fastener molding die as described in claim 1, further comprising manufacturing the electroforming die (6), wherein manufacturing the electroforming die (6) comprises forming the group of sacrificial portions (3) on the support surface (4a) of the support material (4).

3. A method for manufacturing a hook-and-loop fastener molding die as described in 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. The method for manufacturing a hook-and-loop fastener molding die according to claim 3, wherein forming the group of sacrificial portions (3) on the support surface (4a) of the support material (4) includes the 3D printer head (1) forming a first subset of the group of sacrificial portions (3) in a first region of the support surface (4a) and, subsequent to forming the first subset, forming a second subset of the group of sacrificial portions (3) in a second region of the support surface (4a) adjacent to the first region, wherein the multiple sacrificial portions (3) included in the first subset and the multiple sacrificial portions (3) included in the second subset are complementarily positioned so that a non-linear boundary line can be drawn between the first and second regions.

5. A method for manufacturing a hook-and-loop fastener molding die as described in claim 3, wherein the 3D printer head (1) is operable so that the light or thermosetting material ejected at different times merges in the air and lands on the support surface (4a).

6. A method for manufacturing a mold for molding a hook-and-loop fastener as described in 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 the flat surface of the support surface (4a) formed by deformation of the metal sleeve.

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

9. 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. A method for manufacturing a hook-and-loop fastener molding die as described in any one of claims 1 to 6, 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. A method for manufacturing a hook-and-loop fastener molding die as described in 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. A method for manufacturing a mold for molding a hook-and-loop fastener according to any one of claims 1 to 6, wherein each molding cavity (8) of the group of molding cavities (8) penetrates the electroformed film (7).

13. A method for manufacturing a mold for molding a hook-and-loop fastener according to any one of claims 1 to 5, 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 a 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, wherein each 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. 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 consistent throughout 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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