JP4332094B2 - Manufacturing method of molded circuit components - Google Patents

Description

  The present invention relates to a method for manufacturing a molded circuit device (Molded Interconnect Devices) in which a circuit is formed by plating a part of the surface of an internal antenna or the like and plating an inner peripheral surface of a through hole.

  As a conventional method of manufacturing a molded circuit component, the applicant of the present application firstly forms a primary molded product by injecting a plating grade liquid crystal polymer into a cavity having a shape that matches the outer shape of the circuit component. A step of roughening the surface of the molded product, and a step of partially covering the roughened surface of the primary molded product with a coating material made of an oxyalkylene group-containing polyvinyl alcohol resin, excluding the circuit portion to be formed And a step of applying a plating catalyst to a surface other than the coated surface, a step of removing the coating material, and a step of plating the surface of the catalyst. (Patent Document 1). The oxyalkylene group-containing polyvinyl alcohol resin of the coating material in this production method is water-soluble, so it can be easily eluted in hot water, and biodegradable, so it can be reduced naturally without polluting the environment. It was a thing.

As another conventional example, although the manufacturing process is the same as that of the conventional example, there is one that is a mixture or copolymer of polylactic acid or aliphatic polyester mainly composed of polylactic acid as a coating material. (Patent Document 2).
JP-A-11-145583 Claim 6 of JP 2001-240975 A

Recently, materials selected from the group consisting of enzyme-degradable and alkali-degradable polymers, such as polybutylene succinate lactate resin (PBSL), have been proposed as a polymer material. As a result of studying whether it can be applied as a coating material in a method of manufacturing circuit components, it was found that it can be applied. In particular, since this PBSL is more flexible than polylactic acid, it is possible to reproduce the contour of a circuit pattern. It was proved to be extremely effective as a covering material that can be realized, and the present invention has been completed.
The object of the present invention is excellent in adhesion to the secondary molded product, excellent in melt moldability as a coating material for the secondary molded product, advantageous for injection molding, and can easily and easily remove this coating material, An object of the present invention is to provide a method of manufacturing a molded circuit component that can realize accurate reproduction of the contour of a circuit pattern without contamination.

  The first feature of the method for producing a molded circuit component according to the present invention is a step of molding a base body of a primary molded product with a plating-compatible thermoplastic plastic, for example, a plating grade liquid crystal polymer, and roughening the entire surface of the base body. A step of covering the roughened surface with a coating material, except for a circuit portion to be formed, partially covering the surface, and a step of applying a plating catalyst to a surface other than the coated surface; The method comprises a step of removing the coating material and a step of plating the catalyst-providing surface, wherein the coating material is selected from the group consisting of an enzyme-degradable polymer and an alkali-degradable polymer. It is in.

  The second feature of the present invention is that the enzymolytic and alkali-degradable polymer of the coating material in the first feature is polymerized with succinic acid, 1.4 butanediol, and lactic acid, of which the ratio of lactic acid A mixture or co-polymer of polybutylene succinate lactate resin (PBSL) having a content of 40% or less, at least one enzyme-degrading accelerator selected from adipic acid, polyethylene glycol, and glycerin, and an alkali-degrading accelerator. There is a polymer.

  The third feature of the present invention is that the enzymatic degradation by PBSL is removed by immersing in an aqueous solution of 1 to 10% by weight of the enzyme and immersed in an aqueous solution at a temperature of 25 to 80 ° C. for 1 to 240 minutes. The fourth feature of the present invention is that alkaline decomposition by PBSL is performed by immersing in an aqueous solution of 2 to 15% by weight of caustic soda (NaOH) or caustic potash (KOH) for 1 to 240 minutes in an aqueous solution at a temperature of 25 to 80 ° C. And is being removed.

  As an effect of the present invention, since a plating-compatible thermoplastic is used for the substrate, the surface is roughened, so that it has excellent adhesion to the secondary molded product, and as a covering material for the secondary molded product, enzymatic decomposability and alkaline decomposition. Since a material selected from the group consisting of functional polymers is used, it is advantageous for injection molding because of its excellent melt moldability. Further, this coating material can be easily and easily removed with an aqueous enzyme solution or an aqueous alkaline solution. Because it is biodegradable, it can be reduced naturally without polluting the environment. As described above, the covering material of the secondary molded product can be completely removed by hydrolysis with an aqueous enzyme solution or an alkaline aqueous solution, so that it does not remain in the molded circuit component that is the final product, and an accurate circuit pattern contour reproduction can be realized. This part can be molded to the minimum required size. Further, since the catalyst can be applied only to a portion not covered with the coating material, that is, a range necessary for circuit molding, the catalyst material is not wasted.

  In particular, the coating material polybutylene succinate lactate resin (PBSL) is manufactured from plant-derived raw materials and is therefore biodegradable, and it can be used in the atmosphere whether it is biodegraded by bacterial microorganisms or incinerated. It is so-called carbon neutral without increasing carbon dioxide.

  Hereinafter, the best embodiment according to the present invention will be described with reference to FIGS. 1A to 1F. FIG. 1A is a base body which is a primary molded product molded in a primary molding step. 1, the outer shape matches the molded circuit component (FIG. 1 (F)), which is the final product. In the present invention, the surface of the substrate is partially plated. Although not shown, a plating-compatible thermoplastic is injected and molded in a cavity formed on the opposite surface of the mold with the mold closed.

An example using a plating compatible thermoplastic, for example, a plating grade liquid crystal polymer will be described.
This liquid crystal polymer is of an aromatic polyester type, and is, for example, plating grade C810 of “Vectra” (trade name of Polyplastics Co., Ltd.).
An example of injection molding conditions in the molding process of the substrate 1 is as follows:
Material "Vectra" plating grade C810
Cylinder temperature 320 ° C
Mold temperature 110 ℃
Injection pressure 1200Kg / cm ²
Cooling time 20 seconds

  FIG. 1B shows the process of roughening the entire surface of the substrate 1. When there are outer peripheral surfaces of the substrate and through holes, all surfaces such as the inner peripheral surface of the through holes are rough surfaces 11. Is. For this purpose, the substrate 1 is degreased and the surface is roughened (etched). As an example of this etching process, an alkaline aqueous solution in which caustic soda or caustic potash is dissolved at a predetermined concentration, for example, 45 wt% is heated to a predetermined temperature, for example, 50 to 90 ° C., and the substrate 1 is immersed for a predetermined time, for example, 30 minutes. By this etching process, the entire surface of the substrate 1 is roughened.

  FIG. 1 (C) shows a secondary molded product 2 molded by the secondary molding process, which is not shown in the figure, but on the opposing surface of the normal upper and lower molds, on the outer periphery of the base 1, A cavity having a shape matching the shape having a gap is formed, and in this cavity, a circuit portion 4 formed in a molded circuit component described later is not left as a gap. After the base body 1 is inserted into the inside, the covering material 21 is injected into the cavity and molded while the mold is closed. Therefore, the roughened surface 11 is partially covered with the covering material 21 except for the concave portion 21a which is the circuit portion 4 to be formed (see FIG. 1F). This is the secondary molded product 2.

  The covering material 21 is selected from the group consisting of enzyme-decomposable and alkali-degradable polymers. Examples of the enzyme-degradable and alkali-degradable polymers include enzyme-degradable and alkali-degradable polymers. Polybutylene succinate lactate (Poly Butylene Succinate Lactate, PBSL), the composition of which is polymerized with succinic acid, 1.4 butanediol, and lactic acid, of which the ratio of lactic acid is 40% or less. It is a mixture or copolymer of at least one enzyme degradation accelerator selected from adipic acid, polyethylene glycol, and glycerin, mainly composed of PBSL, and an alkali degradation accelerator. This PBSL is obtained by direct dehydration polycondensation of succinic acid, 1.4 butanediol and lactic acid as described above. This succinic acid is produced from plant-derived raw materials such as starch, and this PBSL is biodegradable. This has higher physical properties than polylactic acid known as a plant-derived resin.

An example of the injection molding conditions of the molding process of the secondary molded product 2 on which the covering material 21 is formed is as follows:
Material PBSL
Cylinder temperature 220 ° C
Mold temperature 90 ℃
Injection pressure 800Kg / cm ²
Cooling time 30 seconds

  FIG. 1D shows a step of applying a plating catalyst 3 made of palladium, gold or the like to the roughened surface of the substrate 1 exposed at the bottom of the recess 21a other than the surface covered with the coating material 21. As is well known, for example, this catalyst application method is performed by immersing the secondary molded product 2 in a mixed catalyst solution of tin and palladium, and then activating with an acid such as hydrochloric acid or sulfuric acid, To precipitate. Alternatively, a relatively strong reducing agent such as stannous chloride is adsorbed on the surface and immersed in a catalyst solution containing a noble metal ion such as gold to deposit gold on the surface. What is necessary is just to immerse the temperature of a catalyst liquid at 15-23 degreeC for 5 minutes.

  FIG. 1 (E) shows a step of removing the covering material 21, and the covering material 21 formed on the secondary molded article 2 after the application of the catalyst is removed by enzymatic decomposition or alkaline decomposition. This enzymatic degradation is removed by immersing in an aqueous solution of 1 to 10% by weight of the enzyme in an aqueous solution at a temperature of 25 to 80 ° C. for about 1 to 240 minutes. In addition, the removal by hydrolysis with an alkaline aqueous solution is performed by immersing in an aqueous solution having a concentration of caustic alkali (caustic soda NaOH, caustic potassium KOH, etc.) of about 2 to 15% by weight and a temperature of about 25 to 80 ° C. To remove.

  Then wash with water. As a result, the catalyst 3 is applied to the portion of the substrate 1 on which the surface 11 shown in FIG.

  FIG. 1 (F) shows a process of forming the circuit 4 plated on the catalyst-providing surface 3, and chemical copper plating, chemical nickel plating, or the like is appropriately employed as the plating means. After the circuit is formed, a heat treatment is finally performed to remove moisture in the interior to form a conductive circuit, thereby completing a molded circuit component as a final product.

  As an application example of the invention, a circuit is formed by plating a part of the surface or the inner peripheral surface of a through hole in an internal antenna such as a mobile phone.

(A) Sectional drawing of the base | substrate of a primary molded article which shows a 1st process. (B) Sectional drawing of the state which shows the 2nd process and the surface of the base | substrate is roughened. (C) Sectional drawing of the secondary molded product which shows a 3rd process and in which a part of base | substrate is coat | covered with the coating | covering material. (D) Sectional view showing the fourth step, with the catalyst applied to the surface of the substrate exposed from the coating material. (E) Sectional drawing of the state which showed the 5th process and removed the coating | covering material from the secondary molded article. (F) Sectional view of the state in which a circuit is formed by plating the catalyst-providing surface of the substrate, showing the sixth step.

Explanation of symbols

1 Base (Primary molded product)
DESCRIPTION OF SYMBOLS 11 Rough surface of base | substrate 2 Secondary molded product 21 Coating | covering material 21a Recessed part 3 Catalyst providing surface 4 Plated circuit

Claims (4)

A method of partially plating the surface of a substrate,
Forming a substrate from a plating compatible thermoplastic;
Roughening the entire surface of the substrate;
A step of partially covering the roughened surface with a covering material except for a circuit portion to be formed; and
Providing a plating catalyst on a surface other than the coated surface;
Removing the covering material;
Comprising the step of plating the above-mentioned catalyst-attached surface,
The method for manufacturing a molded circuit component, wherein the coating material is selected from the group consisting of enzyme-degradable polymers . A method of partially plating the surface of a substrate,
Forming a substrate from a plating compatible thermoplastic;
Roughening the entire surface of the substrate;
A step of partially covering the roughened surface with a covering material except for a circuit portion to be formed; and
Providing a plating catalyst on a surface other than the coated surface;
Removing the covering material;
Comprising the step of plating the above-mentioned catalyst-attached surface,
The coating material is mainly composed of polybutylene succinate lactate resin (PBSL), which is polymerized with succinic acid, 1.4 butanediol, and lactic acid, and the ratio of lactic acid is 40% or less. Adipic acid, polyethylene glycol method for producing a molded circuit component, wherein, or at least one enzyme degradable promoter selected from glycerin, and mixtures or copolymers of alkali-decomposable promoter. 3. The method for producing a molded circuit component according to claim 2, wherein the coating material is an aqueous solution of 1 to 10% by weight of an enzyme and is removed by immersion in an aqueous solution at a temperature of 25 to 80 ° C. for 1 to 240 minutes. . In Claim 2, the said coating | covering material is caustic soda (NaOH) or the caustic potash (KOH) 2-15 weight% aqueous solution, It is immersed for 1 to 240 minutes in the aqueous solution of temperature 25-80 degreeC, and is removed. A method for producing a molded circuit component.

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