JP6405180B2 - Production method of porous electroforming - Google Patents

Description

  The present invention relates to a method for producing porous electroforming that can be suitably used as a mold for vacuum molding, blow molding, or the like.

  An electroforming mold can accurately copy the irregularities of a mother mold, and is used, for example, in a precision plastic molded product that reproduces a textured surface imitating a leather product. Among electroforming dies, porous electroforming dies with many holes penetrating in the thickness direction of electroforming are used to remove gas generated from a parison or a heated sheet during molding, By extracting air from the inside, the surface of the mold can be accurately transferred, and therefore, it can be suitably used for molds such as plastic blow molding and vacuum molding. In particular, when the molded product has steep convex portions, in other words, when the mold for manufacturing the molded product has deep concave portions, a large number of through holes for suction are essential.

  Conventionally, as a method for producing porous electroforming, a method has been developed in which electroforming is performed after a number of bottomed holes are provided by a drill or the like on the surface of a matrix on which a conductive film is formed (Patent Document 1). ). In this method, since the conductive coating is scraped off by providing the holes, no plating layer is formed in the holes. Also, current concentrates on the plating layer around the hole, hydrogen gas bubbles are generated as a side reaction of the electrodeposition reaction during plating, and the bubbles stay to prevent the plating layer from entering the hole. be able to. As a result, an electroformed layer having a through hole extending from the matrix side to the opposite side is formed. By controlling the position, density and hole diameter of the holes provided in the matrix, the position, density and hole diameter of the through holes formed in the electroformed layer can be controlled. Thereby, it is possible to manufacture a porous electroforming suitable for use in a mold such as plastic blow molding or vacuum molding.

  As another method for producing porous electroforming, a mother die in which hydrophobic powder is dispersed is prepared, and the mother die is plated in a plating solution that does not substantially contain a surfactant. Therefore, there is a method of making the porous plating (Patent Document 2).

JP-A-5-156486 JP2013-147695A

  However, in the method for producing porous electroforming described in Patent Document 1, since a plating solution to which a surfactant is not added is used in order to prevent desorption of hydrogen gas bubbles from the holes, other than holes are not desired. There was a problem that hydrogen gas stayed at the position and a through hole was formed. For example, as shown in FIG. 11, the end portion 101 of the porous electroforming 100 is welded to a metal frame 102 as a flange to be finished into a vacuum mold. In particular, the end portion 101 tends to concentrate current during plating, and the generation of hydrogen gas increases. In addition, the end 101 is often placed horizontally in the plating solution for reasons such as facilitating placement of the matrix, and thus hydrogen gas bubbles are likely to stay (when placed vertically, When the lower hydrogen gas bubbles are desorbed, they are combined with the upper hydrogen gas bubbles and desorbed together, making it difficult for the hydrogen gas bubbles to stay). As a result, a large number of through holes are generated in the end portion 101, and there is a problem that the strength of welding with the frame body 102 becomes insufficient. In addition, in the plating of ordinary electroforming molds that are not porous electroforming molds, in order to prevent hydrogen gas bubbles from staying on the plating surface, a surfactant is added to the plating solution to prevent the formation of through holes due to hydrogen gas bubbles. doing.

  Furthermore, in the production of an electroforming mold, it is necessary to make the thickness of the electroformed layer uniform in order to make the heat distribution at the time of use uniform. However, since electroplating uses an electroplating technique, there is a fundamental problem that the corners and protrusions of the master mold are thick and the plating of the recesses is thin. As a countermeasure to this problem, the whole mold is pulled up from the solution during plating to grind the part with excessive plating, and masking with adhesive tape to prevent further plating on the part Is required. When the plating is performed again after this operation, the hydrogen gas bubbles do not always stay in the through holes generated by the hydrogen gas bubbles staying from the hole, so that the penetration holes are blocked by the penetration of the plating. There was a problem.

  The present invention has been made in view of such problems in the field, and it is possible to provide through holes having a desired density and hole diameter at a desired position and prevent the formation of through holes at undesired positions. It is an object to be solved to provide a method for producing porous electroforming having the strength required for an electroforming mold.

In the present invention, in order to solve the above problems, the following three measures are taken. That is,
(1) By providing a hole that penetrates the conductive film on the matrix resin and reaches the matrix resin, hydrogen gas bubbles easily adhere to and stay in the hole and prevent the plating film from entering the hole.
(2) In the manufacture of conventional porous electroforming, by deliberately adding a surfactant (a pit prevention agent) that was not added to the plating solution, adhesion of hydrogen gas bubbles other than the pores was suppressed. The formation of through holes at undesired positions is suppressed.
(3) By adding water-repellent powder to the matrix resin, the water-repellent powder is exposed in the holes provided in (1), and hydrogen gas bubbles are reliably retained in the holes. To do.

  That is, the porous electroforming production method of the present invention includes a mother mold forming step of forming a powder-containing mother mold in which electrically insulating water-repellent powder is contained at least near the surface, and the powder. Forming a conductive film on the surface of the body-containing matrix, forming a plurality of holes reaching the powder-containing matrix from the surface of the conductive film, and forming the holes; And a plating step of forming a porous plating film by electroplating the prepared matrix with a conductive film in an electroplating solution to which a surfactant is added.

In the method for producing porous electroforming according to the present invention, first, as a mother die forming step, a powder-containing mother die in which a water-repellent powder having electrical insulation is contained at least near the surface is formed. Here, “electrically insulating” means that the surface of the water-repellent powder is electrically insulative in addition to the case where the water-repellent powder itself is made of a material having electrical insulating properties. It also includes the case where it is processed. In addition, “the water-repellent powder is contained at least near the surface” means that the water-repellent powder is present only in the vicinity of the surface of the matrix, This also includes the case where is present.
The water-repellent powder can be used as long as it is a water-repellent powder having at least an electrically insulating surface and does not dissolve or decompose in the plating solution. Examples of such water-repellent powder include inorganic powders (eg, hydrophobized silica, hydrophobized alumina, etc.) whose surface is modified with a polyethylene resin, a fluororesin powder such as PTFE, and a silane coupling agent. Hydrophobized titania, etc.).

  Further, in the conductive film forming step, a conductive film is formed on the surface of the powder-containing matrix. For forming the conductive film, for example, a method of reducing silver ions with a reducing agent to form a silver thin film can be used.

  After the conductive film forming step is thus performed, a plurality of holes reaching the powder-containing matrix from the surface of the conductive film are formed (hole forming step). As a result, the matrix material and the water-repellent powder contained in the matrix are exposed in the hole. Drilling or laser processing can be used to form the holes.

Finally, as a plating step, electroplating is performed in a plating solution to which a surfactant is added to a matrix with a conductive film in which holes are formed. The kind of electroplating is not specifically limited, For example, nickel, iron, cobalt, nickel-cobalt alloy etc. are mentioned. In the plating step, since a conductive film is present in portions other than the holes, a plated film is formed. However, since there is no conductive film in the holes, no plated film is formed. Furthermore, on the plating film around the hole, hydrogen gas is generated by the electrolysis reaction of water, which is a side reaction of the plating reaction, and it grows into bubbles, which becomes a water repellent powder that is exposed in the hole. Adhere (because the bubbles are hydrophobic and therefore easily adhere to the water-repellent resin). And since the adhering bubbles and the larger bubbles in which the bubbles are collected, the plating film around the hole is prevented from entering the hole. By performing plating in such a state, a hole penetrating the plating film is reliably formed on the hole.
Therefore, according to the method for manufacturing a porous electroforming of the present invention, it is possible to manufacture a porous electroforming having a through hole surely at a place where a hole is formed.

The reason why the surfactant is added to the plating solution in the electroplating process is as follows.
In the manufacturing method of porous electroforming in Patent Document 1, in order to solve the above-mentioned problem that the through hole of the plating film is blocked, plating is performed without adding a surfactant to the plating solution. When a surfactant is not added to the plating solution, hydrogen gas generated as a side reaction of plating is difficult to desorb from the plating surface. Therefore, as shown in FIG. This is because the hydrogen gas generated from the gas grows into a large bubble 203, and this bubble 203 prevents the plating film from entering the hole 200. However, when the surfactant is not added to the plating solution, the hydrogen gas bubble It becomes difficult to detach from the plating surface and easily adheres not only to the holes but to the entire plating film. For this reason, hydrogen gas bubbles adhere not only to the positions where the holes are provided but also to the other plated film surface, and as a result, there is a possibility that through holes may be formed at undesired positions.
In order to solve such a trade-off problem, in the method for producing a porous electroforming according to the present invention, a surfactant is added to the electroplating solution.
That is, in the present invention, a surfactant is added to the electroplating solution, but the water-repellent particles mixed in the matrix are exposed on the surface in the pores, so that hydrogen gas adheres to the water-repellent particles. As a result, the plating film is not detached and the penetration of the plating film into the hole is prevented, and the through-hole is reliably formed. (Refer to Fig. 7) In addition, hydrogen gas bubbles generated at positions other than the holes on the conductive film or plating film are easily detached from the plating surface, preventing the formation of through holes in the plating film at undesired positions. can do. As a result, the through holes can be selectively generated only at the positions where the holes are provided. For this reason, when using porous electroforming as a mold for vacuum forming, blow molding, etc., it is possible to open through holes at desired locations at the desired density as designed, and to perform more precise plastic molding Is possible.

  In the present specification, “surfactant is added” means that the surfactant is added at such a concentration that the hydrogen gas bubbles adhering to the plating film can be easily released. A state in which an activator is added. Specifically, the surfactant is preferably added in an amount of 0.01 g / L or more, more preferably 0.05 g / L or more, and most preferably 0.25 g / L or more. On the other hand, with respect to the upper limit of the addition amount of the surfactant, it is allowed to be added within a range that does not disturb the retention of hydrogen gas bubbles in the pores. Specifically, it is preferably 10 g / L or less, more preferably 2 g / L or less, and most preferably 1 g / L or less.

As a matrix forming step in the method for producing porous electroforming according to the present invention, a prepolymer curable with a curing agent, the curing agent, and a water-repellent powder having at least an electrically insulating surface are mixed. Thus, a method comprising a mixing step to obtain a viscous mixture and a solidification step in which the viscous mixture is molded and solidified to obtain a matrix can be used.
In this method, first, as a mixing step, a prepolymer, a curing agent, and a water-repellent powder are mixed to form a viscous mixture. The prepolymer is not particularly limited as long as it is a liquid prepolymer that can be cured by a curing agent and can be mixed with the water-repellent powder. Examples of such prepolymers include epoxy resin prepolymers, urethane resin prepolymers, and silicon resin prepolymers. Among these, the epoxy resin-based prepolymer is suitable because it is excellent in mechanical strength when cured, and therefore has a small degree of deformation due to stress received from the plating film.

  The viscous mixture obtained in the mixing step is based on a prototype formed of silicon resin or the like, poured into the mold, solidified by heating, light irradiation, or the like, and taken out to form a mother mold. In this way, a powder-containing matrix in which the water-repellent powder exists up to the inside of the matrix can be formed.

In addition, as a matrix forming step in the method for producing porous electroforming of the present invention,
The matrix forming step comprises mixing a prepolymer curable with a curing agent, the curing agent, and a water-repellent powder having at least a surface electrically insulating property to form a viscous mixture, It is also possible to adopt a mother die forming step comprising an application step of applying a viscous mixture to a master and a solidification step of solidifying the viscous mixture applied to the master to obtain a mother die.
By doing so, it is possible to form a powder-containing matrix in which the water-repellent powder exists up to the inside of the matrix.

  In the porous electroforming production method of the present invention, it is preferable to control the surface tension of the electroplating solution to 28 mN / m or more and 65 mN / m or less. When the surface tension of the electroplating solution is 65 mN / m or less, hydrogen gas bubbles generated on the plating film are easily detached from the plating surface, and hydrogen gas bubbles adhere to the plating film at an undesired position. Can be prevented. In addition, when the surface tension of the electroplating solution is 28 mN / m or more, hydrogen gas attached to the water-repellent powder that is exposed in the hole is easily maintained in the attached state. For this reason, while it is possible to reliably form a through-hole in the plating film at the position of the hole, it is possible to prevent the formation of a through-hole at other undesired positions. It is possible to more reliably form a through hole having a desired density and hole diameter at the position. More preferably, the surface tension of the electroplating solution is controlled to 30 mN / m or more and 45 mN / m or less.

In the method for producing porous electroforming according to the present invention, the mother die is taken out from the plating solution during the plating step, and a non-conductive and hydrophobic substance is applied to the inner wall surface of the through hole formed on the hole. Alternatively, the coating / filling step of filling the through hole with a non-conductive and hydrophobic substance may be performed at least once.
In the plating step in the production of porous electroforming, the plating film is not formed with a uniform thickness on the matrix, but the plating film at the corners and the protrusions becomes thicker than necessary. For this reason, a step of taking out the matrix from the plating solution in the middle of the plating process and scraping and thinning the plating film at the corners and convex portions where the plating film has become thicker than necessary is necessary. When the plating process is performed again after scraping and thinning the thickened plating film, hydrogen gas bubbles adhering to the hole have been removed, so if hydrogen gas bubbles stay again around the hole periphery However, there is a possibility that the plated film may block the through hole of the electroformed layer formed on the hole.
In the middle of the plating process, the matrix is taken out of the plating solution, and a non-conductive and hydrophobic substance (for example, paint) is applied to the inner wall surface of the through hole formed on the hole, or the non-filled hole is not applied to the through hole. If the application / filling process of applying or filling a conductive and hydrophobic substance is performed at least once, the hydrogen gas adhered to the through-hole formed on the hole when the mother die is taken out of the plating solution Even if the bubbles disappear, hydrogen gas bubbles generated from the plating film around the through-holes of the electroformed layer adhere to the non-conductive and hydrophobic substance at the stage of re-plating, and the plating film is formed on the electroformed layer. It can be prevented that the penetrating into the through hole is blocked.
As the non-conductive and hydrophobic substance, for example, a material having plasticity such as an adhesive silicone resin can be used. By filling the through hole of the electroformed layer with such plasticity, grinding scraps will not fill the through hole of the electrodeposition layer even when grinding a thickly plated part, There is an advantage that it is possible to smooth the plating surface which has been knurled by grinding, and it is easy to perform masking with an adhesive tape to prevent further electrodeposition of plating.

  Further, water repellent powder may be dispersed in the non-conductive and hydrophobic substance. If this is the case, the bubbles of hydrogen gas are more likely to adhere to portions where non-conductive and hydrophobic substances are applied or filled, and the plating film can be more reliably prevented from entering and closing the through holes. be able to.

FIG. 3 is a process diagram of a method for manufacturing porous electroforming of Example 1. It is a perspective view which shows the production process of a silicon rubber original pattern. It is a perspective view of a silicon rubber prototype. It is a perspective view which shows the production process of an epoxy mother mold. It is a perspective view of an epoxy matrix. 3 is a schematic cross-sectional view showing a manufacturing process of porous electroforming of Example 1. FIG. It is a schematic cross section near the hole 9 in the plating step. 6 is a process diagram of a method for manufacturing porous electroforming of Example 2. FIG. 5 is a schematic cross-sectional view showing a manufacturing process of porous electroforming of Example 2. FIG. 6 is a schematic cross-sectional view showing a manufacturing process of porous electroforming of Comparative Example 1. FIG. It is the schematic cross section which showed the state which attached the frame material and the reinforcing material to the electrocast shell. It is a schematic cross section of the hole part in plating which shows that the penetration | invasion of the plating film to a hole is prevented by the bubble of hydrogen gas.

Hereinafter, an embodiment of the present invention will be described with reference to the process diagram (FIG. 1).
Example 1
・ Manufacture of silicon rubber prototype (prototyping step S0)
As shown in FIG. 2, the leather 1 was affixed to the bottom of the square container 2 so that the embossed surface was on the upper side. And after pouring the silicon rubber prepolymer 3, after heating within an electric heater, it took out and allowed to cool naturally, and the hardened plate-like silicon rubber prototype 4 was taken out (see FIG. 3).

-Preparation of epoxy matrix (mixing step S1 and matrix forming step S2)
An epoxy prepolymer composition 6 (300 to 1000 g) in which polytetrafluoroethylene powder (1 to 30 g), a curing agent, and an epoxy prepolymer are mixed well is prepared. Then, as shown in FIG. 4, the silicon rubber pattern 4 was attached to the bottom of the square container 5 so that the transferred textured surface was on the upper side, and the epoxy prepolymer composition 6 (300 to 1000 g) was poured. . Here, the polytetrafluoroethylene powder is a water-repellent powder.

  Then, after heating in the electric heater, taking out and allowing to cool, the silicon rubber pattern 4 is peeled off, so that a large amount of polytetrafluoroethylene is formed on the epoxy base material 7a as shown in FIG. 6 (a). An epoxy matrix 7 (see FIG. 5) in which the powder 7b was dispersed was obtained.

-Conductive film formation by silver mirror reaction (conductive film formation process S3)
Further, by simultaneously spraying a silver mirror solution and a reducing solution onto the surface of the epoxy matrix 7 obtained as described above, a silver mirror film 8 was formed as shown in FIG. Here, the silver mirror film 8 is a conductive film.

-Hole forming step S4
Further, as shown in FIG. 6 (c), holes 9 having a diameter of 0.05 to 0.3 mmφ and a depth of 0.5 to 2 mm are formed on the surface provided with the silver mirror film 8 by a drill at intervals of 0.3 to 1 cm in length and width. Evenly provided.

-Formation of electroformed film in sulfamic acid bath (plating step S5)
A porous nickel plating film was formed by the following sulfamic acid bath as a plating step on the epoxy matrix 7 with the silver mirror film 8 in which the holes 9 were thus formed. Electrolysis was performed at a current density of 0.5 to 2.0 A / dm2. The pH of the bath was 3.0 to 4.0, and the bath temperature was 40 to 50 ° C.
Sulfamic acid bath composition:
Nickel sulfamate 300-350g / L
Nickel chloride 5-10g / L
Boric acid 30-40g / L
Surfactant 5.0mL / L
(A pit inhibitor made by Murata Co., Ltd. (containing 10% by weight of surfactant) was used as a surfactant.)
Surface tension of plating solution: 34mN / m
The surface tension of the plating solution was measured by a droplet method. That is, the number of drops when a sample of a certain volume and pure water was dropped from the burette was counted, and the surface tension of the sample was obtained from the following formula from the number of drops and the specific gravity of the sample and pure water.

  In this plating step, as shown in FIG. 7A, nickel is deposited on the conductive silver mirror film 8, and the nickel plating film 10 becomes thicker with time. On the other hand, since the surface of the hole 9 does not have conductivity, nickel does not precipitate. Furthermore, since the current density increases at the periphery of the hole 9 in the nickel plating film 10, hydrogen gas is generated by electrolysis of water, which is a side reaction, and grows into bubbles 11. Since the bubbles 11 are hydrophobic, they are firmly attached to the water-repellent polytetrafluoroethylene particles 7b exposed in the holes 9 and become larger as time passes to block the holes 9 (FIG. 7 ( b)). Due to the adhering bubbles 11, the plating film 10 around the hole 9 is prevented from entering the hole 9, and the through hole reaching the opposite surface side from the matrix side of the plating film 10 on the hole 9. 12 is reliably formed. (See Fig. 6 (d))

・ Removal of electroformed layer (peeling step S6)
After completion of the plating step, the epoxy mother mold 7 on which the nickel plating film 10 having the through holes 12 shown in FIG. 6D is pulled up, washed with water, the nickel plating film 10 is peeled off from the epoxy mother mold 7, and further washed with water. And dry. Thus, the intended porous electroforming having a textured surface (see FIG. 6E) was obtained. Light was observed from a portion corresponding to the hole 9 by illuminating one surface side of the porous electroforming with an LED light source and visually observing from the other surface side. From this, it was found that the through hole 12 was formed in the portion corresponding to the hole 9. As described above, according to the method for manufacturing porous electroforming of Example 1, it is possible to manufacture a porous electroforming in which the through holes 12 are reliably present at the positions where the holes 9 are formed. Since the hole 9 can be formed at a desired position with a desired diameter and a desired density by drilling or laser processing, by extension, the through hole 12 can be formed at a desired position with a desired diameter and a desired density. .

(Example 2)
In Example 2, as shown in FIG. 8, after the plating step S51 is completed, the epoxy matrix is lifted from the plating solution, washed with water, dried, and then fine nozzles are formed in the through holes 12 of the electroformed layer formed at the positions of the holes. The silicone adhesive 12a was filled using a jig with (see filling step S52, FIG. 9B). Thereafter, the thick plating portion was ground to a specified thickness (grinding step S53). Furthermore, masking with an adhesive tape was performed on the ground portion and the portion where plating was applied to the specified plating thickness (masking step S54), and plating was performed again in the plating solution. The above steps S51 to S54 were repeated 5 times. Other steps are the same as those in the first embodiment, and the same steps are denoted by the same reference numerals and the description thereof is omitted.

(Comparative Example 1)
In Comparative Example 1, the filling step S52 was not performed, and the others were interrupted during plating in the same manner as in Example 2 and then plated again.

  In Example 2, since the thick part of the plating film formed on the epoxy matrix in the middle of the plating step S5 is scraped, the shape of the porous electroforming can be adjusted so that it can be easily used as a mold. Further, since the silicone adhesive 12a is contained in the through hole 12 of the nickel plating film 10, the plating film does not block the hole. Furthermore, grinding dust such as nickel powder does not enter the hole. In addition, when plating is performed again even though the plating is interrupted, as shown in FIG. 9C, hydrogen gas is generated at the periphery of the through hole 12 where the current concentrates, and bubbles 12b are formed as a silicone adhesive. It adheres to 12a. For this reason, the growth to the through-hole 12 side of the nickel plating film 10 is blocked | prevented, and there is no possibility that the diameter of the through-hole 12 may become narrow (refer FIG.9 (d)).

  On the other hand, in Comparative Example 1, when the plating is interrupted and the plating is restarted, as shown in FIG. 10A, the hydrogen gas generated by the side reaction of the plating is applied to the plating film due to the surfactant. In some cases, it is not difficult to adhere, and at the place where the nickel plating film 10 is detached from the hole, the nickel plating film 10 partially grows toward the through hole 12 as shown in FIG. Became narrower (see FIG. 10B).

Examples 3-1 to 3-4 and Comparative Example 2
In order to investigate the effect of adding a surfactant to the electroforming plating solution, the following test was performed.
The epoxy resin prepolymer was mixed with 10% by weight of fluororesin particles (manufactured by Asahi Glass, product number L169E) and further mixed with a curing agent to obtain an epoxy paint containing fluororesin particles. This epoxy paint was applied to the surface of a prototype made of an epoxy plate with a thickness of several millimeters and cured by heating (length 30 cm × width 18 cm × thickness 2 cm). A silver mirror coating and a reducing solution are simultaneously sprayed on the test piece to form a silver mirror coating, and then cut into a size of 6 × 15 cm. On each test piece, a surface other than the silver mirror coating surface (that is, the side surface and the back surface). A masking tape was applied and masked. Further, a bottomed hole having a depth of about 1 mm was uniformly provided at intervals of about 7 mm using a drill having a diameter of 0.18 mm on the surface of the silver mirror coating. Further, one 7 mm diameter bottomed hole was made at the end of the test piece, and the cathode terminal was pressure-bonded to the silver mirror surface with a plastic bolt and a plastic nut to obtain a terminal for energization.

The electroforming plating solution used had the same composition as the plating solution used in Example 1 except for the concentration of the surfactant. As a surfactant, a pit inhibitor made by Murata Co., Ltd. is used, and a predetermined amount of plating solution is used (2.5 mL / L in Example 3-1, 5.0 mL / L in Example 3-2, Example 3). 7.5 mL / L for Example-3 and 10.0 mL / L for Example 3-4) were added and plated in a test plating tank (inside dimensions 16.5 × 29 × liquid depth 12 cm). . In Comparative Example 2, the same operation was performed without adding the surfactant. In addition, the test piece is arranged at the time of plating by inclining 30 degrees from the vertical in the plating solution with the side of 15 cm of the test piece facing down (that is, as an angle raised by 60 degrees from the horizontal). Plating was performed with Ni anodes arranged vertically on both sides. Plating current density was 0.5A / dm ^2, the current flows 0.45A necessary specimen area 0.9dm ^2.

<Evaluation>
After performing plating for 24 hours as described above, the plating film was peeled off from the epoxy resin, and “the number of holes in the drill hole” and “the number of through holes in the plating layer formed on the drill hole” that were initially opened in the mother die And “the number of through-holes of the plating layer generated in a place other than the hole on the drill hole” was measured. As a result, as shown in Table 1, in Examples 3-1 to 3-4 to which a surfactant was added, the number of through holes generated other than on the mother die was as small as 6 or less, which was not intended. It was found that the generation of through-holes can be substantially prevented. On the other hand, in Comparative Example 2 in which the surfactant was not added to the plating solution, the number of through holes generated other than on the mother mold hole was as large as 42, and through holes at unintended locations were considerably generated. I found out. In addition, from the comparison in Examples 3-1 to 3-4, as the amount of the surfactant added increases, the number of through holes generated outside the hole in the mother die decreases, but the drill hole opened in the mother die It was found that the reproducibility of the through-hole in the above was lowered.

  Further, the interfacial tension of the plating solutions used in Examples 3-1 to 3-4 and Comparative Example 2 was measured by a droplet method.

The results are shown in Table 2. From the results of Table 2 and Table 1 above, the reproducibility of the through holes on the drill holes drilled in the mother die is high, and the number of through holes (other than the desired through holes) generated other than on the mother die holes is calculated. In order to reduce the concentration, it is preferable to adjust the concentration of the surfactant so that the surface tension of the plating solution is 28 mN / m or more and 65 mN / m or less, and more preferably 30 mN / m or more and 45 mN / m or less. It turned out to be adjusted as follows.

  The present invention is not limited to the description of the embodiment of the invention. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 1 ... Leather, 2 ... Square container, 3 ... Silicon rubber prepolymer, 4 ... Silicon rubber prototype, 5 ... Square container, 6 ... Epoxy prepolymer composition (viscous mixture), 7b ... Polytetrafluoroethylene powder (water repellency) (Powder), 7 ... epoxy matrix (powder-containing matrix), 8 ... silver mirror film (conductive film), 9 ... hole, 10 ... porous plating film, 11 ... hydrogen gas bubble, 12 ... through hole, 12a ... Non-conductive and hydrophobic substance, 100 ... Porous electroforming, 101 ... End, 102 ... Frame, 200 ... Hole, 201 ... Plating coating, 202 ... Conductive coating, 203 ... Bubble S0 ... Prototype formation process , S1 ... mixing step, S2 ... matrix forming step, S3 ... conductive film forming step, S4 ... hole forming step, S5, S51 ... plating step, S52 ... filling step (coating / filling step), S53 ... grinding step, S54: Masking process,
S6 ... peeling process

Claims (6)

A matrix forming step of forming a powder-containing matrix in which electrically repellent water-repellent powder is contained at least near the surface;
A conductive film forming step of forming a conductive film on the surface of the powder-containing matrix;
Forming a plurality of holes reaching the powder-containing matrix from the surface of the conductive coating so that the water-repellent powder is exposed in the holes; and
A plating step of forming a porous plating film by electroplating the matrix with a conductive film in which the holes are formed in an electroplating solution to which a surfactant is added;
A method for producing porous electroforming comprising:   The matrix forming step is a mixing step in which a prepolymer curable by a curing agent, the curing agent, and a water-repellent powder having at least an electrically insulating surface are mixed to form a viscous mixture; The method for producing a porous electroforming according to claim 1, further comprising: a solidifying step in which the viscous mixture is molded and solidified to obtain a matrix. The matrix forming step is a mixing step in which a prepolymer curable by a curing agent, the curing agent, and a water-repellent powder having at least an electrically insulating surface are mixed to form a viscous mixture;
An application step of applying the viscous mixture to a master;
The method for producing a porous electroforming according to claim 1, further comprising: a solidifying step of solidifying the viscous mixture applied to the original mold to obtain a mother mold.   The method for producing a porous electroforming according to any one of claims 1 to 3, wherein the surfactant is added so that a surface tension of the electroplating solution is 28 mN / m or more and 65 mN / m or less.   In the middle of the plating process, the matrix is removed from the plating solution, and a non-conductive and hydrophobic substance is applied to the inner wall surface of the through hole formed on the hole, or the non-conductive and hydrophobic substance is applied to the through hole. The method for producing a porous electroforming according to any one of claims 1 to 4, wherein the coating / filling step of coating or filling a conductive substance is performed at least once.   6. The method for producing porous electroforming according to claim 5, wherein water-repellent powder is dispersed in the non-conductive and hydrophobic substance.

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