In-mold molding method

Abstract

This is an in-mold molding method in which an insert body is placed in a mold for resin molding, and the resin injected into the mold and the insert body are molded integrally, the method including the steps of: an insert body preparation step of forming a first opening in the insert body; a sheet-like body preparation step of forming a second opening in the sheet-like body that overlaps and communicates with part or all of the first opening in a planar view; a positioning step of aligning the first opening and the second opening and placing the sheet-like body and the insert body, which have been bonded together, at predetermined positions in the mold; a mold clamping step of closing the mold with the sheet-like body and the insert body in position; a molding step of injecting resin into the clamped mold and penetrating the resin from the first opening to the second opening to mold the insert body and the resin integrally; and a peeling step of opening the mold and peeling the sheet-like body from the insert body.

Description

[Technical field]

[0001] The present invention relates to an in-mold molding method. [Background technology]

[0002] A method for manufacturing an insert molded product in which a resin insert body is integrally joined by insert molding to a plate-shaped molded product main body made of a resin material having a melting point higher than that of the constituent resin of the insert body, the method comprising the steps of: preparing an insert body having a recess on a joining surface with the molded product main body; and providing a molding die having a molding cavity formed therein, the molding cavity comprising a receiving portion for receiving and positioning the insert body and a molding portion having a shape corresponding to the molded product main body, the method including the steps of: forming a joining portion of the molded product main body with the insert body while the insert body is received in the receiving portion of the molding cavity; A method for manufacturing an insert molded product is known, which includes the steps of: preparing an insert molding mold, the joint forming portion of which includes a portion having a flow path width that is larger than the flow path width of the portion of the molded part other than the joint forming portion by at least the depth of the recess of the insert body; and accommodating the insert body into a storage portion of a molding cavity formed inside the insert molding mold, and then introducing the constituent resin of the molded product body in a molten state into the molding portion of the molding cavity to perform insert molding, thereby molding the molded product body and integrally joining the insert body to the molded product body (Patent Document 1).

[0003] There is also known a method for manufacturing an integrated conductive circuit molded product, which includes the steps of preparing a lower conductive circuit sheet including a base sheet, a circuit pattern formed on the base sheet, and resin through holes formed in areas other than the circuit pattern, placing the lower conductive circuit sheet in a cavity of an injection molding die, and injecting molten resin into the cavity to pass the resin through the resin through holes formed in the lower conductive circuit sheet, pressing an end of the lower conductive circuit sheet into a recess for forming an engagement portion formed in the lower surface die, filling the recess for forming the engagement portion with resin, rolling in the end of the lower conductive circuit sheet, and engaging the lower conductive circuit sheet with the underside of a resin molded product (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-58665 A [Patent Document 2] Patent Publication No. 2022-28547 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides an in-mold molding method capable of integrating a part of an insert body with a molding resin without forming a cavity on one of the mold surfaces. [Means for solving the problem]

[0006] In order to solve the above problem, the in-mold molding method according to claim 1 comprises: An in-mold molding method in which an insert body is placed in a mold for resin molding, and a resin injected into the mold and the insert body are integrally molded, an insert body preparation step of forming a first opening penetrating the insert body in a thickness direction; a sheet-like body preparation process for forming a second opening in the sheet-like body so as to overlap a part or all of the first opening in a plan view and communicate with the first opening; a positioning step of holding the sheet-like body and the insert body, which are bonded together by aligning the first opening and the second opening, on a flat surface of one of the molds in which no cavity is formed, and arranging them at a predetermined position within the mold; a mold clamping step of closing the mold with the sheet-like body and the insert body disposed therein; A resin is injected into the clamped mold, and the resin passes through the first opening and is then injected into the second opening. Inside The resin is filled in the A thickness direction of the insert body and a horizontal direction intersecting the thickness direction of the insert body The insert body is in Hold Forming a pressing shape a molding step of integrally molding the resin with the molded article; A peeling process of opening the mold and peeling and removing the sheet-like body from the insert body integrally molded with the resin. It is characterized by:

[0007] The invention described in claim 2 is the in-mold molding method described in claim 1, The sheet-like body has a weak adhesive layer having a weak adhesive strength on the surface to be attached to the insert body. It is characterized by:

[0009] Claim 3 The invention described in claim 1 or 2 In the in-mold molding method described in In the insert body preparation step, an intrusion restriction body that restricts intrusion of the resin between the insert body and the resin in a region where the first opening is formed is further provided. 4. The in-mold molding method according to claim 1, wherein the in-mold molding method comprises:

[0010] In order to solve the above problem, the following claims are provided: 4 The in-mold molding method described in An in-mold molding method in which an insert body is placed in a mold for resin molding, and a resin injected into the mold and the insert body are integrally molded, an insert body preparation step of forming a hole in the insert body; a boss-shaped body preparation process for forming a boss-shaped body having a first through hole having an axis portion and serving as a flow path for the resin, and a second through hole communicating with the first through hole in a direction intersecting the first through hole and serving as the flow path for the resin; a positioning step of fitting the shaft portion of the boss-shaped body into the hole of the insert body to place the boss-shaped body and the insert body at predetermined positions within the mold; a mold clamping step of closing the mold with the boss-shaped body and the insert body disposed therein; a molding process of injecting the resin into the clamped mold, and integrally molding the insert body and the resin in a state in which the boss-shaped body is embedded in the insert body by passing the resin from the first through hole to the second through hole, It is characterized by:

[0011] Claim 5 The invention described in claim 4 In the in-mold molding method described in the boss-shaped body has a flange portion larger than the hole of the insert body, and when the shaft portion is fitted into the hole of the insert body, the flange portion is in close contact with one surface of the insert body via a weak adhesive layer having a weak adhesive strength; It is characterized by: Effect of the Invention

[0012] According to the invention recited in claim 1, a part of the insert body can be integrated with the molding resin without forming a cavity on one of the surfaces of the mold.

[0013] According to the invention as recited in claim 2, the sheet-like body can be peeled off from the insert body while preventing misalignment between the sheet-like body and the insert body.

[0015] Claim 3 According to the invention described in the above, deformation of the insert body can be suppressed.

[0016] Claim 4According to the invention described in the above, a part of the insert body can be integrated with the molding resin without forming a cavity on one of the mold faces.

[0017] Claim 5 According to the invention described in the above, it is possible to prevent the boss-shaped body from falling off. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1A is a schematic plan view showing an example of a circuit board manufactured by the in-mold molding method according to the first embodiment, and FIG. 1B is a schematic cross-sectional view. [Diagram 2] 6 is a diagram showing an example of overlap between a first opening and a second opening formed in a sheet-like body. FIG. [Diagram 3] FIG. 3A is a schematic plan view showing an example of a circuit board provided with an entrance restrictor, and FIG. 3B is a schematic cross-sectional view. [Figure 4] FIG. 4A is a schematic plan view showing an example of an insert body having a first opening formed therein, and FIG. 4B is a schematic cross-sectional view explaining the flow of resin in an injection molding die that integrally molds the insert body and a resin layer. [Diagram 5] FIG. 2 is a flow chart showing an example of a schematic procedure of an in-mold molding method according to the first embodiment for integrally molding an insert body and a resin layer. [Figure 6] 3A to 3C are schematic partial cross-sectional views of a circuit board during a manufacturing process thereof. [Figure 7] FIG. 7A is a schematic plan view showing an example of a circuit board manufactured by the in-mold molding method according to the second embodiment, and FIG. 7B is a schematic cross-sectional view. [Figure 8] FIG. 8A is a schematic plan view showing an example of an insert body into which a boss-shaped body is fitted, and FIG. 8B is a schematic cross-sectional view illustrating the flow of resin in an injection molding die that integrally molds the insert body and a resin layer. [Figure 9] FIG. 11 is a flow chart showing an example of a schematic procedure of an in-mold molding method according to a second embodiment for integrally molding an insert body and a resin layer. [Figure 10]10A to 10C are partial schematic cross-sectional views of a circuit board in a manufacturing process according to a second embodiment of the present invention. [Figure 11] 1A to 1C are schematic cross-sectional views showing a method for producing a molded body in which a sheet-like body is placed on one of the parting surfaces of a mold and a resin is injected into the mold. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Next, specific examples of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In the following explanation using the drawings, it should be noted that the drawings are schematic and the ratios of the dimensions, etc. may differ from the actual ones, and in order to facilitate understanding, illustrations other than those of components necessary for the explanation have been omitted as appropriate.

[0020] "First embodiment" (1) Overall configuration of the circuit board Figure 1A is a schematic plan view showing an example of a circuit board 1 manufactured by the in-mold molding method of this embodiment, Figure 1B is a schematic cross-sectional view, Figure 2 is a view showing an example of overlap between a first opening 21 and a second opening 31 formed in a sheet-like body 30, Figure 3A is a schematic plan view showing an example of a circuit board 1 provided with an entry control body 7, Figure 3B is a schematic cross-sectional view, Figure 4A is a schematic plan view showing an example of an insert body 4 in which a first opening 21 is formed, and Figure 4B is a schematic cross-sectional view explaining the flow of resin in an injection molding die K that integrally molds the insert body 4 and the resin layer 5. The configuration of the circuit board 1 will be described below with reference to the drawings.

[0021] As shown in FIG. 1, the circuit board 1 is configured to include an insert body 4 having a conductive pattern 3 formed on a first surface 2a of a substrate 2, a resin layer 5 covering a second surface 2b of the substrate 2 opposite the first surface 2a, and a pressing feature 6 that fixes the second surface 2b of the substrate 2 and the resin layer 5 so that they abut against each other on the first surface 2a side of the substrate 2.

[0022] (base material) The substrate 2 is a deformable insulating film- or plate-shaped substrate made of a synthetic resin material. Here, the term "deformable substrate" refers to a substrate that can be deformed after the conductive pattern 3 is disposed thereon, that is, a substrate that can be deformed from a substantially flat two-dimensional shape to a substantially solid three-dimensional shape by thermoforming, vacuum forming, pressure forming, or the like.

[0023] Examples of the substrate 2 include insulating films made of thermoplastic resin materials such as polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamides (PA) such as nylon 6-10 and nylon 46, polyether ether ketone (PEEK), acryl butadiene styrene (ABS), polymethyl methacrylate (PMMA), and polyvinyl chloride (PVC), insulating films made of thermosetting resin materials such as phenol, epoxy, polyimide (PI), unsaturated polyester, polyurethane, silicone, and oxetane, and insulating plates such as glass epoxy (FR-4) and glass composite (CEM3).

[0024] In this embodiment, as described later, the resin layer 5 is insert molded into the insert body 4 having the conductive pattern 3 formed on the first surface 2a of the substrate 2 without using an adhesive layer. Therefore, there is no need to consider the adhesiveness between the substrate 2 and the resin layer 5, and the substrate 2 can be made of not only thermoplastic resin but also thermosetting resin. Examples of thermosetting resin materials include phenol resin, epoxy resin, polyimide resin, unsaturated polyester resin, polyurethane resin, silicone resin, and oxetane resin, and among these, polyimide resin (PI) is particularly suitable.

[0025] The thickness of the substrate 2 is not particularly limited, but is preferably 5 μm to 3 mm, more preferably 12 μm to 1 mm, and most preferably 50 μm to 200 μm. If the thickness of the substrate 2 is too thin, the strength may be insufficient and the substrate 2 may be significantly distorted during the plating process of the conductive pattern 3. Note that this thickness is a condition when the substrate 2 is a film-like substrate, and the substrate 2 to which the present invention is applied is not limited to a film-like substrate.

[0026] The surface of the substrate 2 is subjected to a surface treatment such as a corona treatment, a plasma treatment, a solvent treatment, a primer treatment, etc., in order to uniformly apply the conductive ink containing metal nanoparticles.

[0027] Further, a first opening 21 is formed in the base material 2. The first opening 21 is formed so as to penetrate in the thickness direction, and a resin forming a resin layer 5 described later penetrates through the first opening 21 to form a pressing shape 6, thereby integrating the insert body 4 and the resin layer 5.

[0028] FIG. 2 shows an example of overlap between the first opening 21 and a second opening 31 formed in a sheet-like body 30, which will be described later. In the sheet-like body 30, second openings 31 are formed that overlap and communicate with part or all of the first openings 21 in a plan view, in comparison with the first openings 21 formed in the substrate 2. Fig. 2A shows an example in which the second openings 31 overlap and communicate with all of the first openings 21, and Fig. 2B shows an example in which the second openings 31 overlap and communicate with all of the multiple first openings 21. Fig. 2C shows an example in which the second openings 31 overlap and communicate with part of the first openings 21, and Fig. 2D shows an example in which the second openings 31 overlap and communicate with part of the multiple first openings 21.

[0029] (Conductive pattern) When arranging the conductive pattern 3 on the first surface 2a of the base material 2, a base layer (not shown) made of a catalyst such as metal nanoparticles that triggers the growth of metal plating is first formed in a predetermined pattern, and the conductive pattern 3 is formed on the base layer by electrolytic plating or electroless plating. Copper, nickel, tin, silver, gold, etc. can be used as the plating metal, but copper is most preferably used from the viewpoints of extensibility, conductivity, and cost.

[0030] (Electronic Components) 1A shows an example in which the conductive pattern 3 is arranged as a touch sensor 3A, but a plurality of electronic components 3B (not shown) may be attached to the conductive pattern 3. Examples of the electronic components 3B include control circuits, contact sensing and light detection components such as strain, resistance, capacitance, and TIR, tactile or vibration components such as piezoelectric actuators or vibration motors, light emitting components such as LEDs, sound generation or reception components such as microphones and speakers, device operation components such as memory chips, programmable logic chips, and CPUs, digital signal processors (DSPs), ALS devices, PS devices, processing devices, MEMS, and the like.

[0031] (Resin layer) The resin layer 5 is formed so as to cover the second surface 2b of the base material 2, which is opposite to the first surface 2a on which the conductive pattern 3 of the base material 2 is arranged, without an adhesive layer therebetween. As described later, the resin layer 5 is formed by injection molding molten resin in a state in which the insert body 4 on which the conductive pattern 3 is arranged is positioned and set in an injection molding die K (hereinafter simply referred to as die K). At this time, in order to improve the adhesion between the resin layer 5 and the substrate 2, a binder ink that forms an adhesive layer according to the combination of resin materials is usually applied, but in this embodiment, the resin layer 5 is insert molded without an adhesive layer. The substrate 2 and the resin layer 5 are fixed so that the substrate 2 and the resin layer 5 abut against each other by a pressing shape 6 described later. This makes it easy to separate the substrate 2 and the resin layer 5, improving recyclability.

[0032] (Pressing shape) The pressing shape 6 is formed so as to penetrate the first opening 21 formed by penetrating the resin layer 5 in the thickness direction of the base material 2 and protrude toward the first surface 2a side of the base material 2, and the insert body 4 and the resin layer 5 are integrated. The pressing shape 6 is formed by filling the second opening 31 provided in the sheet-like body 30 used for in-mold molding described later with resin, as shown by the arrow in FIG. 4B. The second opening 31 is formed with a second size larger than the first size of the first opening 21 formed in the base material 2. As a result, as shown in FIG. 4A, the resin filling the second opening 31 through the first opening 21 spreads larger than the first opening 21 and holds the insert body 4, and the insert body 4 and the resin layer 5 are integrated. A plurality of pressing shapes 6 may be formed except for the area where the conductive pattern 3 and electronic components of the insert body 4 are arranged.

[0033] (Entry control body) In the region where the first opening 21 is formed, it is preferable to provide an entry regulator 7 between the second surface 2b of the base material 2 and the resin layer 5 to regulate the entry of the resin layer 5. As shown in Fig. 3, the entry regulator 7 is fixed by adhesion so as to be in close contact with the second surface 2b of the base material 2 around the periphery of the first opening 21 formed in the base material 2. Examples of the adhesion method include fixing with an adhesive or attaching with double-sided tape so that the entry regulator 7 does not shift due to the resin pressure of the molten resin. The material of the entrance restrictor 7 is not particularly limited, but it is preferable that the entrance restrictor 7 be made of the same thermoplastic resin material as the material of the resin layer 5 .

[0034] When the resin layer 5 is formed by injection molding, the entry regulating body 7 regulates the entry of the resin layer 5 into the second surface 2b of the substrate 2, which is covered by the pressing shape 6 formed integrally with the resin layer 5, thereby suppressing deformation of the substrate 2 due to the resin pressure when the resin layer 5 is injection molded.

[0035] (2) In-mold molding method FIG. 5 is a flow chart showing an example of a general procedure of an in-mold molding method for integrally molding insert body 4 and resin layer 5, and FIG. 6 is a partial cross-sectional schematic view of circuit board 1 during the manufacturing process of circuit board 1.

[0036] The in-mold molding method according to this embodiment includes an insert body preparation process S11 in which a first opening 21 is formed in the insert body 4, a sheet-like body preparation process S12 in which a second opening 31 is formed in the sheet-like body 30 so as to overlap and communicate with a part or all of the first opening 21 in a plan view, a positioning process S13 in which the sheet-like body 30 and the insert body 4, which have been bonded together by aligning the first opening 21 and the second opening 31, are placed at a predetermined position in a mold K, a mold clamping process S14 in which the mold K is closed with the sheet-like body 30 and the insert body 4 placed in the position, a molding process S15 in which resin is injected into the mold K so as to penetrate the resin from the first opening 21 to the second opening 31 to integrally mold the insert body 4 and the resin, and a molding process S16 in which the mold K is opened to remove the sheet-like body 30. Integral molded with resin Peeled off from insert body 4 and remove The insert body 4 is placed in a mold K for resin molding, and the insert body 4 and resin injected into the mold K are molded integrally with each other.

[0037] (Insert body preparation process S11) In the insert body preparation step S11, first, a first opening 21 is formed in a substantially flat base material 2 formed in a predetermined shape and size, penetrating the base material 2 in the thickness direction (see FIG. 6A). The first opening 21 is a hole that communicates between the cavity CA1 that forms the resin layer 5 and the cavity CA2 that forms the pressing shape 6, and a plurality of first openings 21 are formed in a size that allows the molten resin to pass through according to the size of the pressing shape 6. The opening shape of the first opening 21 is not particularly limited to a circle, a polygon, or the like, as long as it is a shape that allows the molten resin to pass through.

[0038] Then, in order to arrange the conductive pattern 3 on the base material 2, a base layer made of catalyst particles such as metal nanoparticles that trigger the growth of metal plating is formed in a predetermined pattern on the base material 2. Note that, in order to uniformly apply a catalyst ink made of catalyst particles such as metal nanoparticles to the base material 2, it is preferable to perform a surface treatment such as a corona treatment, a plasma treatment, a solvent treatment, or a primer treatment.

[0039] Methods for applying a catalyst ink consisting of catalyst particles such as metal nanoparticles onto the substrate 2 include inkjet printing, silk screen printing, gravure printing, offset printing, flexographic printing, roller coater, brush coating, spraying, knife jet coater, pad printing, gravure offset printing, die coater, bar coater, spin coater, comma coater, impregnation coater, dispenser and metal mask methods, but in this embodiment, the inkjet printing method is used.

[0040] The underlayer formed on the base material 2 is subjected to electrolytic plating or electroless plating to deposit a plating metal on the surface and inside of the underlayer, thereby disposing the conductive pattern 3.

[0041] (Sheet body preparation step S12) In the sheet-like body preparation step S12, second openings 31 are formed in a substantially flat sheet-like body 30 formed in a predetermined shape and size, so as to correspond to the first openings 21. The second openings 31 are formed so as to overlap and communicate with part or all of the first openings 21 in a plan view. Specifically, the second openings 31 are formed so as to be larger than the first openings 21 and communicate with the entire first openings 21 (see Figs. 2A and 2B). Alternatively, the second openings 31 may be formed so as to be the same size as the first openings 21 and communicate with part of the first openings 21 (see Fig. 2C), or so as to be larger than the first openings 21 and communicate with part of the first openings 21 formed in a plurality of places (see Fig. 2D).

[0042] The sheet-like body 30 is a film-like or plate-like resin sheet made of a synthetic resin material, and examples of such resins include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamides (PA) such as nylon 6-10 and nylon 46, and thermoplastic resins such as acryl butadiene styrene (ABS), polymethyl methacrylate (PMMA), and polyvinyl chloride (PVC). In particular, polyethylene terephthalate (PET) is preferred because it has a good balance of economy, a certain degree of heat resistance, chemical resistance, and the like.

[0043] A weak adhesive layer 32 having a weak adhesive strength is formed on the surface of the sheet-like body 30 to be bonded to the insert body 4. The adhesive constituting the weak adhesive layer 32 is preferably one that has an adhesive strength sufficient to prevent the sheet-like body 30 and the insert body 4 from shifting when bonded together during insert molding, and is adhesive enough to allow the sheet-like body 30 to be easily peeled off from the insert body 4 after insert molding. Examples of such adhesives include polyacrylic acid ester copolymer adhesives, polyisobutylene adhesives, and styrene-ethylene-butylene-styrene block copolymer adhesives, but silicone rubber is preferred from the viewpoint of excellent heat resistance and ability to maintain weak adhesion even during insert molding.

[0044] Further, the entry restrictor 7 is attached by adhesion to the second surface 2b of the base material 2 in the region where the pressing shape 6 of the base material 2 is formed (see FIG. 6B). The entry restrictor 7 is attached by adhesion to the second surface 2b of the base material 2 around the first opening 21 formed in the base material 2 so as to be in close contact with the periphery of the first opening 21. Then, the sheet-like body 30 is in-bonded to the first surface 2a of the base material 2 with the first opening 21 and the second opening 31 aligned (see FIG. 6B).

[0045] The sheet-like body 30 may be formed by overlapping a resin sheet 30B in which no openings are formed on a resin sheet in which the second openings 31 are formed (see FIG. 6C). By closing one end of the second openings 31 with the resin sheet 30B, one end of the cavity that forms the pressing shape 6 is formed by the highly smooth resin sheet 30B, and the pressing shape 6 formed by filling the second openings 31 with resin can be easily released when the mold K is opened.

[0046] (Positioning step S13) In the positioning step S13, the insert body 4 with the sheet-like body 30 bonded thereto while aligning the first opening 21 and the second opening 31 is placed on a dividing surface of one of the dies (the fixed side K1 in this embodiment) of the die K (see FIG. 6D ). This makes it possible to form the pressing shape 6 with the resin injected into the die K without forming a cavity in advance on the surface of one of the dies, and to integrally mold the resin layer 5 and the insert body 4.

[0047] (Mold clamping process S14) In the mold clamping step S14, the sheet-like body 30 and the insert body 4, which are bonded together by aligning the first opening 21 and the second opening 31, are placed on the dividing surface of one mold (fixed side K1), and the other mold (movable side K2) is moved and brought into contact with the one mold (fixed side K1) to clamp the mold. As a result, the bonded sheet-like body 30 and the insert body 4 are sandwiched and fixed between both dividing surfaces of the mold K, and the cavity CA1 that forms the resin layer 5 and the cavity CA2 that forms the pressing shape 6 are closed and formed in the mold K.

[0048] (Molding process S15) In the molding step S15, resin is injected into the clamped mold K to fill the cavity CA1. The resin filled in the cavity CA1 forms a resin layer 5 that covers the second surface 2b of the base material 2. The resin filled in the cavity CA1 passes through the first opening 21 formed in the base material 2 and then fills the second opening 31 (cavity CA2) formed in the sheet-like body 30. The resin filled in the cavity CA2 forms a pressing shape 6, and the insert body 4 and the resin layer 5 are integrally molded.

[0049] (Peeling process S16) In the peeling step S16, the mold K is opened and the sheet-like body 30 is peeled off from the insert body 4 (see the arrow in FIG. 6E) to obtain the circuit board 1 in which the insert body 4 and the resin layer 5 are integrally molded (see FIG. 6E). The sheet-like body 30 is attached to the insert body 4 by the weak adhesive layer 32, so that it can be easily peeled off from the insert body 4. The circuit board 1 from which the sheet-like body 30 has been peeled off is fixed by the pressing shape 6 so that the insert body 4 and the resin layer 5 are in contact with each other.

[0050] Thus, according to the in-mold molding method of the present embodiment, the sheet-like body 30, in which the second opening 31 is formed so as to overlap and communicate with a part or all of the first opening 21 formed in the insert body 4, is attached to the insert body 4, the sheet-like body 30 and the insert body 4 are placed at predetermined positions in a mold K, and resin is injected into the mold K to penetrate the resin from the first opening 21 to the second opening 31, thereby integrally molding the insert body 4 and the resin layer 5. Then, the sheet-like body 30 is peeled off from the insert body 4 to obtain the circuit board 1 in which the insert body 4 and the resin layer 5 are integrally molded. This makes it possible to integrate a part of the insert body 4 with the resin layer 5 without forming a cavity on one of the mold faces.

[0051] In this embodiment, an in-mold molding method has been described in which the sheet-like body 30 is attached to the insert body 4 and placed at a predetermined position in the mold K, and resin is injected into the mold K to integrally mold the insert body 4 and the resin layer 5. However, it is also possible to impart a predetermined shape or design to one side of the molded body S without forming a cavity on the surface of one of the molds by placing only the sheet-like body 30A having a predetermined shape or design on one side on the dividing surface of one of the molds (fixed side K1) and injecting resin into the mold K, and then peeling and removing the sheet-like body 30 from the molded body S.

[0052] FIG. 11 is a schematic cross-sectional view showing a method for producing a molded body S in which a sheet-like body 30A is placed on the parting surface of one of the dies (fixed side K1) and a resin is injected into the die K. As shown in Fig. 11A, the sheet-like body 30A has a design including a predetermined shape consisting of projections and recesses or a smooth surface formed on one surface 30Aa. A weak adhesive layer 32 having a weak adhesive strength is formed on the other surface 30Ab opposite to the one surface 30Aa. The weak adhesive layer 32 preferably has an adhesive strength sufficient to prevent the sheet-like body 30A attached to the divided surface of one mold (fixed side K1) from shifting, and an adhesiveness sufficient to allow the sheet-like body 30A to be easily peeled off from the molded body S after insert molding. It is preferable to provide the weak adhesive layer 32 on the one surface 30Aa as well, excluding the design surface.

[0053] 11B, the sheet-like body 30A is placed on the parting surface of one of the dies (fixed side K1) of the die K, and the other die (movable side K2) is moved and brought into contact with the one of the dies (fixed side K1) to clamp the die. As a result, the sheet-like body 30A is sandwiched and fixed on both parting surfaces of the die K, and a cavity CA for forming the resin layer 5 is formed and closed in the die K.

[0054] Resin is injected into the clamped mold K to fill the cavity CA. The predetermined shape or design formed on one surface 30Aa of the sheet-like body 30A is transferred to the resin filling the cavity CA, and the mold K is opened to peel the sheet-like body 30A from the molded body S (see FIG. 11C ). This makes it possible to impart a predetermined shape or design to one surface of the molded body S without forming a cavity on the surface of one of the molds (fixed side K1).

[0055] "Second embodiment" Figure 7A is a schematic plan view showing an example of a circuit board 1A manufactured by the in-mold molding method of this embodiment, Figure 7B is a schematic cross-sectional view, Figure 8A is a schematic plan view showing an example of an insert body 4 into which a boss-shaped body 6A is fitted, and Figure 8B is a schematic cross-sectional view explaining the flow of resin in an injection molding die K that integrally molds the insert body 4 and the resin layer 5. The circuit board 1A according to this embodiment is provided with a boss-shaped body 6A that is embedded in the insert body 4 on the first surface 2a side of the base material 2 and fixes the second surface 2b of the base material 2 and the resin layer 5 so as to abut against each other, and is different from the circuit board 1 according to the first embodiment that is provided with a pressing shape 6 that fixes the second surface 2b of the base material 2 and the resin layer 5 on the first surface 2a side of the base material 2 so as to abut against each other. Therefore, the same components as those of the circuit board 1 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0056] (1) Overall configuration of the circuit board The circuit board 1A is configured to include an insert body 4 having a conductive pattern 3 formed on a first surface 2a of a substrate 2, a resin layer 5 covering a second surface 2b of the substrate 2 opposite the first surface 2a, and a boss-shaped body 6A that is embedded in the insert body 4 on the first surface 2a side of the substrate 2 and fixes the second surface 2b of the substrate 2 so that the second surface 2b and the resin layer 5 abut against each other.

[0057] (base material) A hole 21A (see FIG. 10A) of a first size is formed in the base material 2. The hole 21A is formed so as to penetrate in the thickness direction, and a shaft portion 61 of a boss-shaped body 6A, which will be described later, is fitted into the hole 21A.

[0058] (Boss-shaped body) The boss-shaped body 6A has a shaft portion 61 and is formed with a first through hole 62 which serves as a flow path for the resin, and a second through hole 63 which serves as a flow path for the resin and communicates with the first through hole 62 in a direction intersecting the first through hole 62. The boss-shaped body 6A also has a flange portion 64 which is centered on the shaft portion 61 and spreads out in a direction intersecting the flow direction of the resin in the first through hole 62.

[0059] A weak adhesive layer 64b (not shown) having weak adhesive strength is formed on one surface 64a where the flange 64 comes into contact with the first surface 2a of the base material 2 when the shaft portion 61 of the boss-shaped body 6A is fitted into the hole portion 21A of the base material 2. The adhesive constituting the weak adhesive layer 64b is not particularly limited as long as it has an adhesive strength sufficient to prevent the boss-shaped body 6A and the insert body 4 from shifting during insert molding.

[0060] The boss-shaped body 6A fixes the second surface 2b of the substrate 2 and the resin layer 5 in contact with each other while the resin forming the resin layer 5 penetrates the first through hole 62 and the second through hole 63 communicating with the first through hole 62 and is embedded in the insert body 4, as shown by the arrow in Figure 8B.

[0061] (2) In-mold molding method FIG. 9 is a flow chart showing an example of a schematic procedure of an in-mold molding method for integrally molding insert body 4 and resin layer 5, and FIG. 10 is a partial cross-sectional schematic view of circuit board 1A during the manufacturing process of circuit board 1A.

[0062] The in-mold molding method according to this embodiment includes an insert body preparation step S21 for forming a hole 21A in the insert body 4, a boss-shaped body preparation step S22 for forming a boss-shaped body 6A having a shaft portion 61 and a first through hole 62 serving as a resin flow path and a second through hole 63 communicating with the first through hole 62 in a direction intersecting the first through hole 62 and serving as a resin flow path, and a positioning step S30 for positioning the boss-shaped body 6A and the insert body 4 at a predetermined position in the mold K by fitting the shaft portion 61 of the boss-shaped body 6A into the hole 21A of the insert body 4. The method includes a positioning step S23, a mold clamping step S24 in which the mold K is closed with the boss-like body 6A and the insert body 4 positioned therein, and a molding step S25 in which resin is injected into the mold K so that the resin penetrates from the first through hole 62 to the second through hole 63, embedding the boss-like body 6A in the insert body 4, thereby integrally molding the insert body 4 and the resin, in which the insert body 4 with the boss-like body 6A fitted in it is placed in the mold K for resin molding, and the resin injected into the mold K and the insert body 4 are integrally molded.

[0063] (Insert body preparation process S21) In the insert body preparation process S21, first, holes 21A are formed in a substantially flat base material 2 formed in a predetermined shape and size, penetrating the base material 2 in the thickness direction (see FIG. 10A). The holes 21A are holes into which the shaft portion 61 of the boss-shaped body 6A, which serves as a flow path for the resin, is fitted, and a plurality of holes 21A are formed to match the size of the shaft portion 61 of the boss-shaped body 6A.

[0064] Then, in order to arrange the conductive pattern 3 on the base material 2, a base layer made of catalyst particles such as metal nanoparticles that trigger the growth of metal plating is formed in a predetermined pattern on the base material 2. Note that, in order to uniformly apply a catalyst ink made of catalyst particles such as metal nanoparticles, the base material 2 is preferably subjected to a surface treatment such as a corona treatment, a plasma treatment, a solvent treatment, a primer treatment, or the like.

[0065] The underlayer formed on the base material 2 is subjected to electrolytic plating or electroless plating to deposit a plating metal on the surface and inside of the underlayer, thereby disposing the conductive pattern 3.

[0066] (Boss-shaped body preparation step S22) In the boss-shaped body preparation process S22, a boss-shaped body 6A is formed having an axis 61 and a first through hole 62 which serves as a flow path for the resin, and a second through hole 63 which communicates with the first through hole 62 in a direction intersecting the first through hole 62 and serves as a flow path for the resin. The boss-shaped body 6A is formed with a flange 64 that extends from the shaft 61 in a direction intersecting the flow direction of the resin in the first through-hole 62. A weak adhesive layer 64b (not shown) having weak adhesive strength is formed on one surface 64a where the flange 64 comes into contact with the first surface 2a of the base material 2, and adheres to the first surface 2a of the base material 2 when the shaft 61 of the boss-shaped body 6A is fitted into the hole 21A of the base material 2 (see FIG. 10B ).

[0067] The boss-shaped body 6A fixes the second surface 2b of the substrate 2 and the resin layer 5 in contact with each other while the resin forming the resin layer 5 penetrates the first through hole 62 and the second through hole 63 communicating with the first through hole 62 and is embedded in the insert body 4.

[0068] (Positioning step S23) In the positioning step S23, the insert body 4 with the boss-like body 6A fitted therein is placed on a parting surface of one of the dies (the fixed side K1 in this embodiment) of the die K (see FIG. 10C ). This makes it possible to integrally mold the insert body 4 and the resin layer 5 with the boss-like body 6A embedded in the insert body 4 by the resin injected into the die K without forming a cavity in advance on the surface of one of the dies.

[0069] (Mold clamping process S24) In the mold clamping step S24, the mold K is closed with the boss-shaped body 6A and the insert body 4 in place. In the mold clamping step S24, the insert body 4 with the shaft portion 61 of the boss-like body 6A fitted into the hole portion 21A of the insert body 4 is placed on a parting surface of one of the molds (in this embodiment, the fixed side K1) of the mold K, and the other mold (movable side K2) is moved and brought into contact with the one of the molds (fixed side K1) to clamp the mold. As a result, the boss-like body 6A and the insert body 4 are sandwiched and fixed between both parting surfaces of the mold K, and the cavity CA1 for forming the resin layer 5 in the mold K and the cavity CA2 for embedding the boss-like body 6A in the insert body 4 are closed and formed (see FIG. 10C ).

[0070] (Molding process S25) In the molding step S25, resin is injected into the clamped mold K to fill the cavity CA1. The resin filled in the cavity CA1 forms a resin layer 5 that covers the second surface 2b of the substrate 2. The resin filled in the cavity CA1 passes through the first through hole 62 and the second through hole 63 of the boss-shaped body 6A fitted in the insert body 4 and fills the cavity CA2. The insert body 4 and the resin layer 5 are integrally molded with the boss-shaped body 6A embedded in the insert body 4 by the resin filled in the cavity CA2.

[0071] When the mold K is opened and the molded product is taken out, the boss-shaped body 6A is locally embedded in the insert body 4, and the circuit board 1A in which the insert body 4 and the resin layer 5 are integrally molded is obtained (see FIG. 10D).

[0072] Thus, according to the in-mold molding method of this embodiment, a boss-shaped body 6A having an axis 61 and a first through hole 62 which serves as a resin flow path, and a second through hole 63 which communicates with the first through hole 62 in a direction intersecting the first through hole 62 and serves as a resin flow path, is fitted into the hole 21A of the insert body 4, and the boss-shaped body 6A and the insert body 4 are positioned at predetermined positions within the mold K, and resin is injected into the mold K which is then clamped, and the resin is passed through the first through hole 62 to the second through hole 63, embedding the boss-shaped body 6A in the insert body 4, thereby integrally molding the insert body 4 and the resin layer 5. This makes it possible to integrate a part of the insert body 4 with the resin layer 5 without forming a cavity on one of the mold surfaces. [Explanation of symbols]

[0073] 1, 1A... Circuit board 2: base material, 2a: first surface (conductive pattern side), 2b: second surface, 21: first opening, 21A: hole 3. Conductive pattern 4. Insert body 5. Resin layer 6. Pressing shape 6A Boss-shaped body 30, 30A... Sheet-shaped body 31...Second opening, 32...Weak adhesive layer K...Injection mold CA1, CA2...cavity

Claims

1. An in-mold molding method in which an insert body is placed in a mold for resin molding, and a resin injected into the mold and the insert body are integrally molded, an insert body preparation step of forming a first opening penetrating the insert body in a thickness direction; a sheet-like body preparation process for forming a second opening in a sheet-like body, the second opening overlapping a part or all of the first opening in a plan view and communicating with the first opening; a positioning step of holding the sheet-like body and the insert body, which are bonded together by aligning the first opening and the second opening, on a flat surface of one of the molds in which no cavity is formed, and arranging them at a predetermined position within the mold; a mold clamping step of closing the mold with the sheet-like body and the insert body disposed therein; a molding process in which a resin is injected into the clamped mold, the resin penetrates through the first opening, and fills the second opening, and the insert body is pressed in a thickness direction to be integrally molded with the resin; A peeling step of opening the mold and peeling the sheet-like body from the insert body. The in-mold molding method according to the present invention comprises the steps of:

2. The sheet-like body has a weak adhesive layer having a weak adhesive strength on the surface to be attached to the insert body. The in-mold molding method according to claim 1 .

3. The resin is filled into the second opening from the first opening and spreads in a horizontal direction intersecting with the thickness direction of the insert body, forming a pressing shape that presses the insert body in the thickness direction. The in-mold molding method according to claim 2 .

4. In the insert body preparation step, an intrusion restriction body is further provided around the first opening to be in close contact with a back surface of the insert body and restrict the intrusion of the resin.

4. The in-mold molding method according to claim 1, wherein the in-mold molding method comprises:

5. An in-mold molding method in which an insert body is placed in a mold for resin molding, and a resin injected into the mold and the insert body are integrally molded, an insert body preparation step of forming a hole in the insert body; a boss-shaped body preparation process for forming a boss-shaped body having a first through hole having an axis and serving as a flow path for the resin, and a second through hole communicating with the first through hole in a direction intersecting the first through hole and serving as the flow path for the resin; a positioning step of fitting the shaft portion of the boss-shaped body into the hole of the insert body to place the boss-shaped body and the insert body at predetermined positions within the mold; a mold clamping step of closing the mold with the boss-shaped body and the insert body disposed therein; a molding process of injecting the resin into the clamped mold, and integrally molding the insert body and the resin in a state in which the boss-shaped body is embedded in the insert body by passing the resin from the first through hole to the second through hole, The in-mold molding method according to the present invention comprises the steps of:

6. the boss-shaped body has a flange portion larger than the hole of the insert body, and when the shaft portion is fitted into the hole of the insert body, the flange portion is in close contact with one surface of the insert body via a weak adhesive layer having a weak adhesive strength; The in-mold molding method according to claim 5 .

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