JP2009179823A - Plastic spring having conductive circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of facilitating the integration of an electronic circuit, saving the consumption of noble metals incorporated in a catalyst, and forming a precise conductive circuit by an electroless plating process. <P>SOLUTION: An injection-molded first spring substrate 2 is roughened, a coating material 3 made of polylactic acid or the like is partially applied thereto, so as to form a second spring substrate 4, and a catalyst 5 is applied thereto. The catalyst 5 stuck to the surface of the hydrophobic coating material 3 is removed by water cleaning. Next, the part 4a to be formed with electroplating not coated with the coating material 3 is subjected to electroless plating having an acidic or neutral bath composition, so as to form a conductive circuit 6, thereafter, the coating material 3 is hydrolyzed with an alkaline solution, so as to be removed. Since the coating material 3 has acid resistance, it is not dissolved with the acid or neutral electroless plating liquid, further, the coating material 3 is removed after the electroless plating, the problem that the catalyst 5 applied to the part 4a to be formed with electroless plating drops out with the alkaline solution does not occur. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a synthetic resin spring in which a conductive circuit is formed on the surface of a synthetic resin spring base.

  Conventionally, in a three-dimensional conductive circuit or the like in which a plurality of substrates are stacked at a predetermined interval, spring-like connection terminals have been used as means for electrically connecting the electrodes and the like of each substrate to each other. (For example, refer to Patent Documents 1 to 3.)

  That is, Patent Document 1 discloses a configuration in which a metal plate-like terminal pin 2 is implanted on a synthetic resin support 1. The upper end portion of the terminal pin 2 protrudes from the upper surface of the support body 1, and the lower end portion of the terminal pin has a bifurcated shape and protrudes from the lower surface of the support body. Therefore, when the support body 1 is stacked up and down, the upper end part of the terminal pin protruding from the upper surface of the lower support body is inserted and engaged with the bifurcated lower end part of the terminal pin 2 protruding from the lower surface of the upper support body. Both are electrically connected.

  On the other hand, in Patent Document 2, a bonding pad 1a formed on a semiconductor chip 1 and an electrode 3a formed on a substrate 3 are formed by a spring-like protruding electrode 2 formed on the surface of the electrode. A configuration for electrical connection is disclosed. In addition to a metal spring such as nickel, the protruding electrode 2 is formed by laminating a plurality of layers of photocurable resin on the surface of the electrode 3a to form a spring-shaped protrusion, and electroless plating is applied to the outer surface of the conductor. And a material in which a plurality of layers of a photo-curing resin mixed with a metal material is laminated to form a spring-like protrusion.

  In Patent Document 3, a lead-like spring mechanism 3b is integrally projected on one side of a synthetic resin locating housing 3, and this spring mechanism is brought into contact with a side surface of the opposing housing 4. A configuration for electrically connecting the two is described. The locating housing 3 made of synthetic resin has a surface plated so as to have conductivity, thereby taking measures against electromagnetic interference.

  Conventionally, there are various methods for producing molded circuit components in which the surface of a base made of an insulating material is partially covered with a coating material, and a plating layer is formed on a portion not covered with the coating material. In this manufacturing method, there has been proposed a manufacturing method in which this coating material can be easily eluted and removed. For example, the surface of the substrate is roughened, and the roughened surface is partially coated with a coating material made of a polyvinyl alcohol resin that is a water-soluble polymer material, and after the catalyst is applied, the coating material is washed away with water, There is a method of manufacturing a molded circuit component in which a conductive circuit is formed by performing electroless plating on a surface portion of a substrate to which a catalyst adheres because it is not covered with a coating material (see, for example, Patent Documents 4 and 5).

Also, the surface of the substrate is roughened, and the roughened surface is partially coated with a coating material made of polylactic acid or the like, which is a hydrolyzable polymer material, and after the catalyst is applied, the coating material is hydrolyzed with an alkaline solution. There is a method of manufacturing a molded circuit component in which a conductive circuit is formed by performing electroless plating on a portion where the catalyst is adhered because it is not covered with a coating material (see, for example, Patent Document 6).
JP-A-8-31492 (FIG. 7 etc.) Japanese Unexamined Patent Publication No. 2005-11845 (FIG. 5 etc.) Japanese Utility Model Laid-Open No.2-129689 (FIG. 1 etc.) JP-A-11-145583 (pages 1 to 4) JP 2000-80480 A (pages 1 to 8) JP 2002-344116 A (pages 1 to 4)

  The inventor of the present application has found that the conventional conductive spring member described above has the following points to be further improved. That is, since all of these conductive spring members are conductive, for example, when connecting highly conductive circuit boards to each other via this conductive spring member, In order to electrically isolate the conductive spring member and the peripheral components, it is necessary to sandwich an insulating layer such as an insulating film on the side surface of the conductive spring member. In addition, in order to connect highly integrated conductive circuits to each other via a conductive spring member, the size of the spring member must be extremely small. In addition, there is a limit to miniaturization in size from the viewpoint of connection to a conductive circuit.

  Therefore, the present inventor has conceived that the above-described problems can be solved by forming a conductive circuit by partially plating the surface of the insulating spring member. That is, if a conductive circuit is formed only on the surface of the insulating spring member, for example, only on the front surface or the back surface, the portion where the conductive circuit is not formed, that is, both side surfaces of the spring member remain insulative. Therefore, it is not necessary to sandwich an insulating layer such as an insulating film on the side surface of the conductive spring member. Further, if a plurality of rows of conductive circuits are formed on the surface of the insulating spring member, the conductive circuits having a high degree of integration can be connected to each other without reducing the size of the spring member. It is possible to connect to each other via the spring member formed with the.

  However, in order to complete the above-described new idea, that is, a means for forming a conductive circuit by partially plating on the surface of an insulating spring member, there is a further problem to be solved. That is, in the method described in Patent Document 4 or 5, a polymer material such as a water-soluble polyvinyl alcohol-based resin is used as the coating material, so that the surface of the coating material swells in the catalyst application step. As a result, the catalyst adhering to the surface of the coating material cannot be removed by washing. For this reason, when the coating material is dissolved and removed in the subsequent step, the catalyst is also mixed with the solution, and the mixed catalyst is discarded along with the disposal of the solution. However, since rare metals such as palladium and gold are used for the catalyst, it is necessary to sufficiently consider resource saving for these precious metals.

  In addition, in the method described in Patent Document 6, a hydrolyzable polymer material such as polylactic acid or aliphatic polyester is used as a coating material, and an alkaline solution is used to accelerate hydrolysis after imparting a catalyst. In this step of removing the covering material, in the step of removing the covering material, the surface portion of the substrate that is not coated with the covering material, that is, the catalyst applied to the portion that forms the conductive circuit, is also washed with this alkaline solution. As a result, there is a problem that the electroless plating is not sufficiently deposited on the portion where the conductive circuit is formed.

  Furthermore, since all of the means of Patent Documents 4 to 6 described above perform electroless plating after removing the coating material, so-called barrel plating (that is, the substrate is put into the container in a disjointed state) In the initial stage of electroless plating, the catalyst-applied surfaces rub against each other and the catalyst falls off, which may cause a problem of non-plating failure.

  Accordingly, a first object of the present invention is to provide a method of manufacturing a spring made of a synthetic resin having a conductive circuit that facilitates integration of an electronic circuit. The second object is to save resources of precious metals contained in the catalyst and to make the electroless plating sufficiently deposited on the portion where the conductive circuit is formed, and a synthetic resin spring having a conductive circuit. It is in providing the manufacturing method of.

  The characteristic of the synthetic resin spring having the conductive circuit according to the present invention is that the surface of the synthetic resin spring base is partially covered with an acid-resistant coating material, and the portion not covered with this coating material is Forming a conductive circuit by electroless plating, using a hydrolyzable polymer resin that maintains hydrophobicity without swelling by a catalyst solution as the coating material, and applying no coating after coating with this coating material Electrolytic plating is carried out with either an acidic or neutral bath composition, the coating material is dissolved and removed after electroless plating is formed on the portion where the conductive circuit is formed, and after the catalyst is applied, It is to provide a water washing step for washing off the catalyst adhering to the surface and to facilitate the recovery of the washed-out catalyst.

  That is, the method of manufacturing a molded circuit component according to the present invention includes a first step of forming an insulating synthetic resin by injection molding to form a first spring base, and a first step of roughening the surface of the first spring base. And a coating material made of polyglycolic acid or polylactic acid alone, a mixture of polylactic acid and aliphatic polyester, or a copolymer on the surface of the roughened first spring base. A second step of forming a second spring base by covering the surface, a fourth step of applying a catalyst to the surface of the second spring base, and a surface of the coating material of the second spring base A fifth step of removing the remaining catalyst by washing with water and a portion of the surface of the second spring base that is not covered with the coating material, either having an acidic or neutral bath composition. A sixth step of electroless plating 1 and the second spring In further comprising a seventh step of removing the coating material coated on the surface of the body.

  The synthetic resin constituting the first spring base is one of polyetheretherketone (PEEK) resin, polyetherimide (PEI), or a copolymer of polyetherimide and polyimide (PI). It is desirable.

  Between the sixth step and the seventh step, the surface of the first electroless plating is either the first electroplating or the second electroless plating whose bath composition is acidic or neutral. You may provide the 8th process of laminating | stacking either of these.

  Alternatively, after the seventh step, one of the second electroplating or the third electroless plating whose bath composition is acidic, neutral, or alkaline is applied to the surface of the first electroless plating. A ninth step of stacking may be provided.

  In addition, after the seventh step, any one of the third electrolytic plating, which is either acidic, neutral or alkaline, or the fourth electroless plating is applied to the surface of the first electrolytic plating. You may provide the 10th process of laminating | stacking these. Alternatively, after the seventh step, the surface of the second electroless plating may be one of the 4th electroplating or the 5th electroless plating having any one of acidic, neutral or alkaline bath composition. You may provide the 11th process of laminating one.

  Note that the above-mentioned process number, electrolytic plating number, and electroless plating number are all for distinguishing each step, each electrolytic plating, and each electroless plating, and are not necessarily formed according to the present invention. It does not indicate the chronological order of the circuit component manufacturing process.

  Here, the “insulating synthetic resin” is one of polyetheretherketone (PEEK) resin, polyetherimide (PEI), or a copolymer of polyetherimide and polyimide (PI). Is desirable. Further, the “first spring base” corresponds to a coiled helical spring, a plate-shaped spring, and the like. In addition to the single first spring base, the first spring base is also integrally formed as a part of other parts.

  Here, “roughening” means etching for forming small irregularities on the surface of the first spring base, improving the adhesion of the electroless plating layer, and imparting hydrophilicity. For example, using an aqueous solution of an alkali metal hydroxide such as NaOH or KOH, an aqueous solution of an alkali metal alcoholate such as alcoholic sodium or alcoholic potassium, or an organic solvent such as dimethylformamide, these liquids are used as the first substrate. Or the first substrate is immersed in these liquids.

  “Polyglycolic acid” corresponds to the structural formula shown in FIG. “Polylactic acid” corresponds to, for example, Lacia # H-100J / F manufactured by Mitsui Chemicals. “Aliphatic polyester” refers to, for example, an aliphatic polyester composed of polyhydroxycarboxylic acid, hydroxycarboxylic acid, and aliphatic polybasic acid, and a plurality of monomer components selected from hydroxycarboxylic acid and aliphatic polyhydric alcohol And a random copolymer or a block copolymer comprising a plurality of monomer components selected from aliphatic polybasic acids.

  The amount of polylactic acid and aliphatic polyester mixed and copolymerized is preferably about 1 to 10% by weight based on the total amount of the mixture or copolymer. You may mix an alkali decomposition accelerator about 1 to 100 weight% with respect to the whole mixture. Moreover, you may mix the general purpose additive which can be used for synthetic resins, such as an alkali decomposition accelerator, an organic inorganic filler, and a coloring agent, as needed. “Partial coating” means that the conductive circuit is selectively coated, leaving a portion where a conductive circuit is to be formed in a later step. The “second spring base” means a member composed of both the first spring base and a covering material partially covering the surface of the first spring base.

  “Removing with water” means that the catalyst adhering to the surface of the coating material maintaining hydrophobicity is washed away with water. In this water washing, a neutral to alkaline wash water having a pH of 7 or more is used. For example, the second spring base is immersed in a wash water of 15 to 70 ° C. for 5 to 120 seconds and stirred, or 100 to 170 ° C. This corresponds to spraying the cleaning water vapor at a high pressure on the second spring base.

  “Bath composition” means the pH (hydrogen ion concentration) of the electroless plating solution, and “bath composition is acidic or neutral” means that the pH of the electroless plating solution or electrolytic plating solution is 7 or less. It means that. In the present invention, even if the “bath composition” of electroless plating is weakly alkaline of about 7 to 7.5, it acts in the same manner as an acidic or neutral bath composition, but the electroless plating solution is deteriorated. Care must be taken to speed up.

  By partially covering the surface of the insulating first spring base with a coating material and forming the conductive circuit by the first electroless plating, the portions not forming the conductive circuit, for example, both sides of the spring member Since the surface can be kept insulative, there is no need to sandwich an insulating layer such as an insulating film on the side surface of the spring member in order to electrically isolate it from the peripheral components. Further, if a plurality of rows of conductive circuits are formed on the surface of the insulating first spring base, the conductive members having a high degree of integration can be connected to each other without reducing the size of the spring members. It is possible to connect to each other via

  As a coating material, polyglycolic acid, or a simple substance of polylactic acid, a mixture of polylactic acid and aliphatic polyester, or a co-polymer that can be easily removed by hydrolysis and can maintain hydrophobicity without swelling with a catalyst solution. By using the polymer, it is possible to prevent the catalyst from being firmly adhered to the coating material when the catalyst is applied. By providing a water washing step after applying the catalyst, the catalyst adhering to the hydrophobic surface of the coating material can be easily and reliably removed, so that the catalyst washed out in the washing water can be easily separated and recovered. This makes it possible to save resources on expensive precious metals.

  In addition, since the coating material has acid resistance, by performing electroless plating or electrolytic plating with either an acidic or neutral bath composition, dissolution of the coating material is prevented, and a conductive circuit is precisely formed. Can be formed. Furthermore, the coating material is dissolved and removed after the electroless plating is formed on the portion where the conductive circuit is formed, so that the problem of the conventional method of dissolving and removing the coating material before the electroless plating, Since the alkaline solution used for the removal can avoid the problem that even the catalyst applied to the surface of the first spring base that is not coated with the coating material falls off, the electroless plating should be sufficiently deposited. Can do.

  In addition, after removing the coating material, it is no longer necessary to consider the dissolution of the coating material. Therefore, even if the bath composition is acidic, neutral, or alkaline, the electrolytic plating performed before the removal of the coating material is performed. Alternatively, an electrolytic plating or an electroless plating can be further laminated on the electroless plating. Further, the thickness, strength, and the like of the conductive circuit can be increased by stacking electroless plating or electrolytic plating on the electroless plating or electrolytic plating. Further, by stacking platings of different materials, other useful characteristics such as improvement of solderability of the conductive circuit can be imparted.

  Further, the covering material is dissolved and removed after the electroless plating is formed, so that in the case of the electroless plating, the periphery of the portion where the conductive circuit is formed is surrounded by the wall of the covering material. be able to. For this reason, even when barrel plating is performed, it is possible to prevent the portions forming the conductive circuit provided with the catalyst from being rubbed against each other by the wall of the covering material, thereby preventing the occurrence of defective plating adhesion. .

  By using one of polyetheretherketone (PEEK) resin, polyetherimide (PEI), or a copolymer of polyetherimide and polyimide (PI) as the first spring base, the spring member As a result, excellent characteristics can be exhibited. That is, since these synthetic resins all have high fatigue strength and excellent heat resistance and chemical resistance, they are extremely suitable for spring members used in conductive circuits and the like.

  In order to facilitate understanding of the present invention, first, referring to FIGS. 1 to 6, a synthetic resin spring having a conductive circuit manufactured by the manufacturing method according to the present invention (hereinafter referred to as “spring according to the present invention”). )), The mold for injection molding, and the usage mode are outlined. Then, the manufacturing method of the spring by this invention is explained in full detail, referring FIGS. 7-11. FIG. 1 shows a structure in which a spring according to the present invention is formed into a plate-like spring 1. The plate-like spring 1 is composed of a first spring base 2 including two side leads 11 curved in a substantially S-shape and one end portion 12 connecting the two side leads. In addition, the conductive circuits 6 by the first electroless plating are formed respectively. In addition, the first electroless plating is performed so as to also wrap around the upper side surface and the back surface of the one end portion 12 of the plate-like first spring base 2, thereby enabling electrical connection with electrodes facing each other. ing. The two-side leads 11 may be single or three or more sides. Further, the lead 11 is not limited to a substantially S-shape, and may be a lateral U-shape or a zigzag formed plate member.

  FIG. 2 shows a spring according to the present invention configured as a helical spring 101. In the helical spring 101, a conductive circuit 106 is formed by first electroless nickel plating only on the outer surface of the first helical spring body 102 having a square wire cross section. Further, both end surfaces of the first spring base 102 are also subjected to the first electroless plating so as to be able to be electrically connected to electrodes facing each other. The strand cross section is not limited to a square but may be a circle, not limited to a circular spiral, but may be an elliptical or hexagonal other helical shape.

  When connecting the stacked electronic circuits using the helical spring 101, a guide member made of a metal pin or the like is provided at the center of the helical winding, and the helical spring falls down. Etc. can be prevented. That is, since the first electroless nickel plating layer is not formed on the inner periphery of the helical spring 101, an insulating film or the like is insulated between the helical spring and the metal guide member. There is no need to sandwich layers. Conversely, if the first electroless nickel plating is performed only on the inner circumference and both end faces of the helical spring 101, a metal guide member provided so as to surround the outer circumference of the helical spring; There is no need to sandwich an insulating layer such as an insulating film between them. Therefore, it becomes easy to mutually connect conductive circuits having a high degree of integration.

  FIG. 3 shows a configuration in which a spring according to the present invention is formed on a lead-like spring 201 as a part of a plate-like panel. The lead-shaped spring 201 is a lead-shaped first spring base 202 that is curved in a substantially S shape and protrudes from one end of a plate-shaped panel at a predetermined interval. Further, a conductive circuit 206 is formed by electroless nickel plating. Note that the conductive circuit 206 extends to the surface of the plate-like panel and is electrically connected to electrodes and the like. The lead-shaped spring 201 is not limited to two or more sides, but may be a single shape, not limited to a substantially S shape, but may be a U shape, a substantially C shape, or the like.

  FIG. 4 shows an example of a mold for injection molding the plate-like first spring base 2 described in FIG. That is, this mold is composed of an upper mold A and a lower mold B that are divided into two vertically along the lower surface of the plate-shaped first spring base 2. A recess C is opened in which the first spring base is embedded. Then, the upper mold A and the lower mold B are overlapped, and a thermoplastic resin is injected into a cavity constituted by the depression C and the lower mold of the upper mold.

  FIG. 5 shows an example of a mold for injection molding the helically wound first spring base 102 described in FIG. That is, this mold has an opening hole having the same diameter as the inner peripheral diameter of the helical spring-shaped first spring base 102, and is fitted into this opening hole with an outer mold D divided into two at 180 degrees. It consists of a cylindrical core E to be inserted. On the inner peripheral surface of the outer die D, the groove F having a wire cross-sectional shape of the helical spring-shaped first spring base 102 is formed in a helical manner, each semi-circularly. Then, in a state where the two outer molds D are overlapped, a cylindrical core E is fitted and inserted into the opening hole at the center. The helically wound first spring base 102 is formed by injecting a thermoplastic resin into a cavity constituted by the outer peripheral surface of the core E and the helically groove F.

  FIG. 6 shows an example of how the plate-like spring 1 described in FIG. 1 is used. The plate-like spring 1 is inserted while being compressed between the substrates G and H facing each other with a predetermined interval. That is, the conductive circuit G1 is formed on the upper surface of the upper substrate G, and the connection terminal G2 is formed on the lower surface. The conductive circuit G1 and the connection terminal G2 are electrically connected by a through hole G3 subjected to conductive plating. A conductive circuit H1 is formed on the upper surface of the lower substrate H. An electronic component I is mounted on the lower surface of the upper substrate G4.

  One end 12 of the plate-like spring 1 is mounted on the upper surface of the conductive circuit H1 formed on the lower substrate H, and both are joined by soldering. On the other hand, the tip portions of the leads 11 on the two sides of the plate-like spring 1 are in pressure contact with the connection terminals D2 formed on the lower surface of the upper substrate G, respectively. Thus, the conductive circuit G1 formed on the upper surface of the upper substrate G and the conductive circuit H1 formed on the upper surface of the lower substrate H are electrically connected to each other via the plate-like spring 1. Connected. In addition, since the electroless plating is not formed in the both sides | surfaces of the plate-shaped spring 1, the insulation with the adjacent electronic component I is ensured. Therefore, it is not necessary to provide an insulating film or the like between the plate-like spring 1 and the adjacent electronic component I.

  Next, the steps of the spring manufacturing method according to the present invention will be described with reference to FIG. FIG. 7 shows a cross section AA of the plate-like spring 1 shown in FIG. First, polyether ether ketone (PEEK) resin, which is a thermoplastic resin, is injection-molded to produce a plate-like first spring base 2 (A). Next, as a second step, the entire surface of the first spring base 2 is roughened by etching (B). This etching is performed by a commonly used method. For example, 400 g / l of chromic anhydride is dissolved in 20 ml / l of sulfuric acid, the temperature is kept at 75 ° C., and the first spring base 2 is immersed for 20 minutes. Next, it is neutralized by dipping in 50 ml / l of hydrochloric acid at a temperature of 50 ° C. for 3 to 5 minutes. By this etching, as shown in the partially enlarged view of FIG. 7B, the entire surface becomes a rough surface 2a having irregularities.

  Next, as a third step, the rough surface 2a of the first spring base 2 is partially covered with the covering material 3 to form the second spring base 4 (C). As the covering material 3, a simple substance of polylactic acid is used, but not limited thereto, a simple substance of polyglycolic acid, a mixture of polylactic acid and an aliphatic polyester, or a copolymer may be used. These resins have a property of hydrolyzing with an alkaline aqueous solution and have a property of being resistant to an acidic aqueous solution. As a covering method, the first spring base 2 having a roughened surface is set in an injection mold, and a predetermined conductive circuit is formed on the rough surface 2a of the first spring base. The portion to be covered is covered with a mold or the like, and a polylactic acid resin is injected into a cavity other than that portion, whereby the covering material 3 is integrally formed on the first spring base. The thickness of the covering material 3 is preferably 0.1 to 1 mm, and more preferably 0.3 to 0.5 mm.

  Next, as a fourth step, a catalyst 5 made of palladium, gold or the like is applied to the entire surface of the second spring base 4 (D). The catalyst 5 is applied by a known method. For example, after immersing the second spring base 4 in a mixed catalyst solution of tin and palladium, the catalyst 5 is activated with an acid such as hydrochloric acid or sulfuric acid to deposit palladium on the surface. Let Alternatively, a relatively strong reducing agent such as stannous chloride is adsorbed on the surface and immersed in a catalyst solution containing noble metal ions such as gold to deposit gold on the surface. What is necessary is just to immerse the temperature of a liquid at 15-23 degreeC for 5 minutes.

  Of the surface of the second spring base 4, an exposed portion that is not covered with the covering material 3, that is, a portion 4 a where a predetermined conductive circuit is to be formed, is roughened by etching in the second step. Thus, the catalyst 5 adheres firmly. On the other hand, since the surface of the covering material 3 maintains hydrophobicity without swelling even by the etching in the second step as described above, the catalyst 5 does not adhere firmly.

  Therefore, as a fifth step, when the second spring base 4 provided with the catalyst 5 is washed with water (E), all of the catalyst remaining on the surface of the covering material 3 can be removed. On the other hand, as described above, the catalyst 5 is firmly attached to the portion 4a where the predetermined conductive circuit is to be formed. Therefore, the catalyst does not fall off even by washing with water. The water washing is performed by immersing the second spring base 4 in a water tank having a temperature of 15 to 25 ° C. and swinging the work for 5 to 30 seconds.

  Next, as a sixth step, electroless nickel plating, which is the first electroless plating having an acidic bath composition, is applied to the portion 4a of the surface of the second spring base 4 that is not covered with the covering material 3. Conductive circuit 6 is formed (F). This electroless nickel plating is performed, for example, by immersing in an acidic bath having a pH of 4.7 and a temperature of 90 ° C. for 35 minutes. As the first electroless plating, electroless gold plating may be performed with a neutral bath composition instead of the electroless nickel plating.

  In addition, since electroless nickel plating or electroless gold plating is performed with an acidic or neutral bath composition, respectively, as described above, the covering material 3 having acid resistance is not dissolved in the plating solution, and the conductive circuit. 6 can be formed precisely.

  Next, as a seventh step, the covering material 3 covering the surface of the second spring base 4 is removed (H). As described above, the polylactic acid or the like of the covering material 3 is resistant to an acidic aqueous solution, but is easily hydrolyzed by an alkaline aqueous solution, so that the second spring base 4 has a concentration of 2 to 15% by weight and a temperature of 25. The coating material 3 is removed by immersing in a caustic (NaOH, KOH, etc.) aqueous solution at ˜70 ° C. for about 1 to 120 minutes. Therefore, the working efficiency is remarkably improved as compared with the manual mask removal. In this case, since the conductive circuit 6 by the first electroless plating has already been formed in the portion 4a not covered with the coating material 3, the catalyst 5 in this portion is alkaline so as to hydrolyze the coating material. It is completely unrelated to the conventional problem of dropping off by the solution.

Now, as shown in FIG. 8, between the sixth step (first electroless plating) and the seventh step (removal of the covering material 3), the conductivity by the first electroless plating is described. An eighth step of forming the secondary plating layer 8 by performing the first electrolytic plating or the second electroless bath composition having an acidic or neutral bath composition on the surface of the circuit 6 can be inserted. For example, when performing electrolytic copper plating as the first electrolytic plating, the bath composition of the acidic copper sulfate bath is CuSO ₄ .5H ₂ O (75 g) / lH ₂ SO ₄ (190 g) / lCl (60 ppm) / additive (Appropriate amount). The anode material is phosphorous copper, the bath temperature is set to 25 ° C., and the cathode current density is 2.5 A / dm 2. As the second electroless, electroless gold plating is performed.

  In this way, even before the seventh step, that is, before the removal of the covering material 3, the eighth step of performing the first electroplating or the second electroless bath having an acidic or neutral bath composition may be inserted. Since the covering material 3 has acid resistance, it does not dissolve in the electrolytic copper plating solution or the like, and the secondary plating layer 8 is accurately formed on the surface of the conductive circuit 6 by the first electroless plating. can do.

  Further, as shown in FIG. 9, after the covering material 3 is removed by the seventh step, the second electrolytic plating is further applied to the surface of the conductive circuit 6 by the first electroless plating (sixth step) described above. Alternatively, a ninth step of forming the secondary plating layer 9 by the third electroless plating can be added.

  Further, as shown in FIG. 10, after the covering material 3 is removed in the seventh step, the third electrolytic plating or the fourth electroless process is performed on the first electrolytic plating (eighth step) described above. A tenth step of forming the tertiary plating layer 10 by plating can also be added. Alternatively, as shown in FIG. 11, after the covering material 3 is removed by the seventh step, the fourth electrolytic plating or the fifth non-electrolytic plating is performed on the second electroless plating (eighth step) described above. An eleventh step of forming the tertiary plating layer 11 by electrolytic plating can also be added.

  In any of the ninth to eleventh steps described above, since the covering material 3 that is hydrolyzed with an alkaline solution has already been removed, the plating bath composition is not only acidic or neutral, but also alkaline. There may be. Further, since the first electroless plating or the like has already been formed on the portion not covered with the covering material 3, the conventional problem is that the catalyst applied to this portion falls off with an alkaline solution. Is completely unrelated.

  Further, a fibrous or particulate filler may be added to a polyether ether ketone (PEEK) resin or the like that is a material of the first spring base 2 or the like. Examples of the fiber include glass fiber, carbon fiber, calcium titanate whisker, aluminum borate whisker, and carbonated whisker whisker. Examples of the particulate filler include calcium carbonate and wollastonite.

  It is possible to stack highly integrated electronic circuits, etc., save valuable precious metals contained in the catalyst, and sufficiently deposit electroless plating on the part forming the conductive circuit. It can be widely used in industries related to equipment.

It is a perspective view of a plate-shaped spring. It is a perspective view of a helical spring. It is a perspective view of a lead-shaped spring. It is a schematic sectional drawing of the metal mold | die for injection molding the 1st spring base | substrate. It is a schematic perspective view of the metal mold | die for injection-molding another 1st spring base | substrate. It is sectional drawing which shows an example of the usage condition of a plate-shaped spring. It is a manufacturing-process figure of a plate-shaped spring. It is a manufacturing-process figure of another plate-shaped spring. It is a manufacturing-process figure of another plate-shaped spring. It is a manufacturing-process figure of another plate-shaped spring. It is a manufacturing-process figure of another plate-shaped spring. It is a chemical structural formula of polyglycolic acid.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 101, 201 Synthetic resin spring 2, 102, 202 having conductive circuit First spring base 3 Covering material 4 Second spring base 5 Catalyst 6, 106, 206 Conductive circuit (first electroless circuit) Plating)
8 Secondary plating layer (first electrolytic plating, second electroless plating)
9 Secondary plating layer (second electrolytic plating, third electroless plating)
10 Tertiary plating layer (third electrolytic plating, fourth electroless plating)
11 Tertiary plating layer (4th electroplating, 5th electroless plating)

Claims (6)

A first step of injection-molding an insulating synthetic resin to form a first spring base;
A second step of roughening the surface of the first spring base;
The surface of the roughened first spring base is partially coated with a coating material made of polyglycolic acid, polylactic acid alone, a mixture of polylactic acid and aliphatic polyester, or a copolymer. A third step of forming a second spring base;
A fourth step of applying a catalyst to the surface of the second spring base;
A fifth step of removing the catalyst remaining on the surface of the covering material of the second spring base with water;
A sixth step of subjecting the surface of the second spring base to a portion that is not covered with the covering material, a first electroless plating whose bath composition is either acidic or neutral;
And a seventh step of removing the covering material coated on the surface of the second spring base. A method of manufacturing a synthetic resin spring having a conductive circuit. 2. The synthetic resin constituting the first spring base according to claim 1, is any one of polyetheretherketone (PEEK) resin, polyetherimide (PEI), or a copolymer of polyetherimide and polyimide (PI). A method for producing a spring made of synthetic resin having a conductive circuit. 3. The method according to claim 1, wherein the bath composition is either acidic or neutral on the surface of the first electroless plating between the sixth step and the seventh step. An eighth step of laminating either electrolytic plating or second electroless plating is provided. A method of manufacturing a synthetic resin spring having a conductive circuit. 2. The first electrolytic plating according to claim 1, wherein the bath composition is any one of acidic, neutral, and alkaline on the surface of the first electroless plating after the seventh step. A method for producing a synthetic resin spring having a conductive circuit, comprising a ninth step of laminating any one of electroless plating. 4. The third electrolytic plating according to claim 3, wherein the bath composition is either acidic, neutral, or alkaline after the seventh step, or the fourth non-electrolytic plating is performed on the surface of the first electrolytic plating. A method for producing a synthetic resin spring having a conductive circuit, comprising a tenth step of laminating any one of electrolytic plating. 4. The fourth electrolytic plating according to claim 3, wherein the bath composition is any one of acidic, neutral, and alkaline on the surface of the second electroless plating after the seventh step. An eleventh step of laminating any one of electroless platings is provided. A method for producing a synthetic resin spring having a conductive circuit.

Images