JP2008140972A - Molded goods having conductive circuit, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide molded goods having conductive circuits and a manufacturing method thereof whereby the molded goods having conductive circuits are obtained surely and the conductive circuits can be formed further more effectively. <P>SOLUTION: Polybuthylene terephthalate having added glass fibers and the compound having added CuCr<SB>2</SB>O<SB>4</SB>are so mixed with each other by a biaxial molding machine as to pelletize the resultant object and then mold it in the form of a sheet by an injection molding machine. Thereafter, a laser beam is so irradiated on the obtained molded body in the direction (arrow direction R) orthogonal to the orientating direction of the glass fibers 2 and an electroless copper plating is so performed to the obtained molded body as to form conductive circuits 3 in the region irradiated by the laser beam. Thereby, the molded body 1 having conductive circuits is obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molded article having a conductive circuit having a conductive circuit formed on its surface and a method for manufacturing the same.

  Conventionally, as a molded article having a conductive circuit, for example, a circuit board having a conductive circuit formed on the surface of a molded article such as a resin substrate has been widely used. As a method for efficiently forming this circuit board, for example, a casing made by injection-molding a compound composed of a composite oxide based on spinel containing polybutylene terephthalate, pyrogenic silicic acid and copper is irradiated with laser light from an Nd: YAG laser. A method of forming a circuit in a portion irradiated with laser light has been proposed (see Patent Document 1) by performing chemical reducing copper plating on the casing after irradiation.

JP-T-2004-534408 (Example 1)

  However, in the method described in Patent Document 1, specific manufacturing conditions are unknown, and a conductive circuit is not always formed, and a circuit may not be formed depending on manufacturing conditions. Moreover, in order to reduce the manufacturing cost of a molded product, while being able to form a circuit reliably, forming a circuit more efficiently is desired.

  The problem to be solved by the present invention is to provide a molded article having a conductive circuit capable of reliably forming a molded article having a conductive circuit and forming the conductive circuit more efficiently, and a method for manufacturing the same. .

  In order to solve the above problems, a molded article having a conductive circuit of the present invention is formed on the surface of a molded article formed from a blend in which a non-conductive inorganic fiber and a copper-containing composite oxide material are added to a thermoplastic resin. It is a molded body in which a conductive circuit is formed by electroless plating in a region irradiated with laser light, and the conductive circuit is formed in a direction crossing the orientation direction of the non-conductive inorganic fiber. To do.

As the thermoplastic resin of the molded body, any resin that can be molded such as injection molding can be used. For example, polybutylene terephthalate is versatile and inexpensive, and has good moldability. It is preferable from the point. The copper-containing composite oxide material is preferably a spinel-type CuCr ₂ O ₄ black pigment. The non-conductive inorganic fiber is preferably a glass fiber. Moreover, you may mix | blend another additive with the said molded object in the range which does not inhibit electrically conductive circuit formation.

  Moreover, in the said molded object, it is preferable that the conductive circuit is formed in the direction orthogonal to the orientation direction of the nonelectroconductive inorganic fiber of a molded object.

  The method for producing a molded article having a conductive circuit according to the present invention includes injection molding a compound obtained by adding a non-conductive inorganic fiber and a copper-containing composite oxide material to a thermoplastic resin, and forming a non-coated surface on the resulting molded article. The gist is that after irradiating laser light in the direction intersecting the orientation direction of the conductive inorganic fiber, the molded body is subjected to electroless plating, and a conductive circuit is formed by electroless plating in the laser light irradiation area. It is.

  In the manufacturing method of the molded body, the conductive circuit composed of the plating layer can be more reliably performed by irradiating the laser beam with an average laser output of 1.3 W or more and an applied energy per unit area of 0.35 J or more. Since it is obtained, it is preferable.

  According to the molded body having the conductive circuit of the present invention, since the conductive circuit is formed in a direction crossing the orientation direction of the non-conductive inorganic fibers, the conductive circuit is reliably formed in the laser light irradiation region. The body is obtained.

  In addition, according to the method for producing a molded article having a conductive circuit of the present invention, a molded article having a conductive circuit can be obtained reliably, the conductive circuit can be formed more efficiently, and the scanning speed in the laser light irradiation process is increased. As a result, productivity can be improved and manufacturing costs can be reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig.1 (a) is a top view which shows a circuit board as an example of the molded article which has this invention conductive circuit. 1 uses polybutylene terephthalate (hereinafter sometimes referred to as PBT) as a thermoplastic resin, glass fibers as non-conductive inorganic fibers, and spinel-type CuCr ₂ as a copper-containing composite oxide material. It is a molded body formed by injection molding a compound to which a black pigment of O ₄ is added and formed into a sheet shape.

  The circuit board 1 in FIG. 1 is formed such that the glass fibers 2 are oriented in the vertical direction in the figure. A conductive circuit 3 is formed on the surface of the circuit board 1 in a direction (indicated by an arrow R in the figure) orthogonal to the orientation direction of the glass fibers 2 (indicated by an arrow D in the figure). In FIG. 1, the glass fiber 2 is schematically shown in order to explain the orientation direction.

  FIG. 1B is an enlarged view showing a conductive circuit of the circuit board of FIG. The conductive circuit 3 of the circuit board 1 has a conductive property by electroless copper plating in the region irradiated with the laser beam L in the direction of the arrow RL, which is a direction orthogonal to the orientation direction of the glass fiber 2 on the surface of the molded body. A circuit made of metallic copper, which is a metal layer, is continuously formed.

Hereinafter, the manufacturing method of the said molded object is demonstrated. A blend of PBT, glass fiber and spinel-type CuCr ₂ O ₄ black pigment is kneaded and extruded into a pellet. A substrate is obtained by molding into a sheet using this pellet injection molding machine. Next, the surface of the substrate is irradiated with laser light. Laser light is irradiated in a direction that intersects with the orientation direction of the glass fibers of the substrate.

After the pre-treatment such as washing is performed on the molded body irradiated with the laser beam on the substrate surface, electroless copper plating is performed. In the region where the laser beam is irradiated on the substrate surface, a metal copper layer is formed continuously by electroless copper plating. When a molded body containing a copper-containing composite oxide material such as spinel-type CuCr ₂ O ₄ is irradiated with laser light, only the irradiated portion is considered to be in a state suitable for plating due to its thermal energy. When electroless plating is performed on the molded body irradiated with laser light, a plating film is formed only on the laser light irradiated portion of the molded body.

  When electroless plating is performed after laser light irradiation, whether or not a plating layer is formed in the laser light irradiation area depends on the laser light irradiation conditions (for example, applied energy per unit area, average output, scan) Speed). In the present invention, when irradiating a region on the surface of the molded body where a conductive circuit is to be formed with laser light, the orientation direction of the non-conductive inorganic fibers such as glass fibers contained in the substrate made of the molded body is orthogonal to the orientation direction. By irradiating the laser beam in the intersecting direction, the applied energy per unit area of the laser beam can be reduced or the scanning speed can be increased.

  The irradiation power of laser light and the range of applied energy per unit area that are preferable for forming a conductive circuit are as follows. It is preferable that the laser beam irradiation apparatus has at least a laser output of 1.3 W or more and an applied energy per unit area of about 0.35 J or more. The wavelength of the laser light is 248 nm, 308 nm, 355 nm, 532 nm, 1064 nm, 10600 nm, or the like. The laser irradiation device is preferably a YVO4 laser patterning device. Electroless plating can be performed using a commercially available electroless copper plating solution or the like.

FIG. 2 is a perspective view showing another example of a molded body having a conductive circuit of the present invention. 2 is an internal three-dimensional circuit board such as a hearing aid. As shown in the figure, this circuit board 1 is formed by injection molding at the position of arrows G1 and G2 (in the figure, the direction is the X-axis direction among X, Y, and Z axes orthogonal to each other). Are formed by injection molding of a PBT containing glass fiber and a spinel-type CuCr ₂ O ₄ black pigment compound. Since this circuit board is formed by the forming device at the gate position, the glass fibers are oriented in the X-axis direction in the same drawing as the arrows G1 and G2. Furthermore, a conductive circuit 3 is formed on the surface of the circuit board in a direction (Y-axis direction) orthogonal to the glass fiber orientation direction. In the molded body and the manufacturing method of the present invention, the glass fibers of the molded body can be oriented so as to be orthogonal to the direction in which the conductive circuit is to be formed by appropriately selecting the gate arrangement and the like in this way. .

Examples of the present invention and comparative examples are shown below.
Example 5 mass of CuCr ₂ O ₄ (manufactured by Fellow Japan: PK3095) as a copper-containing composite oxide material with 95 mass% of polybutylene terephthalate resin (BASF: Ultradur B4300G6) added with 30 mass% of glass fiber. % Of the blended product was mixed with a biaxial molding machine and pelletized at a temperature of about 250 ° C. The pellet was formed into a sheet by an injection molding machine.

  Laser light (wavelength 1064 nm) was irradiated to the above-mentioned molded sheet in a direction orthogonal to the orientation direction of the glass fiber using a laser irradiation device (manufactured by Keyence Corporation: Laser Marker MD-V9620). Various samples were prepared under various laser light irradiation conditions (the laser light irradiation conditions will be described later). The molded sheet irradiated with laser light is ultrasonically cleaned with ion-exchanged water (50 ° C.) for 5 minutes, and then an electroless copper plating solution (Enthone: Enplate Cu872) is used with a heater while stirring the beaker with air. The temperature was maintained, and electroless plating was performed by treating at 43 ° C. for 40 minutes. The laser beam irradiation conditions of the molded body and the formation state of the plating layer were observed. The result is shown in the graph of FIG.

Comparative Example As shown in FIG. 4, except that the laser beam L was irradiated in the same direction DL as the orientation direction of the glass fiber 2 of the molded sheet, the same as in the above example, The formation state of the plating layer was observed. The results are shown in the graph of FIG.

  3 and 5 are graphs showing the relationship between the average output of the laser irradiation apparatus and the applied energy per unit area. In this graph, the plating reaction occurred in the range on the right side of the dotted line and the upper side of the dotted line in the figure. It can be said that the point indicated by the dotted line is the threshold value of the irradiation energy of the laser beam for forming the conductive circuit. That is, if the applied energy per unit area or the laser average output is equal to or greater than this threshold value, it means that a conductive circuit is continuously and reliably formed in the region irradiated with laser light when electroless plating is performed. To do.

In the graph of the example of FIG. 3, the threshold for forming the plating layer is that the average laser output is 1.3 W or more, and the applied energy per unit area (1 mm ² ) is 0.096 J or more. As a result, it was possible to form a plating layer up to a scanning speed of laser light irradiation of 50 mm / s at the maximum. In contrast, in the comparative example, as shown in the graph of FIG. 5, the threshold for forming the plating layer is that the average laser output is 1.3 W or more and the applied energy per unit area (1 mm ² ) is 0.35 J or more. . And the scanning speed of the laser beam irradiation which can form a plating layer was 10 mm / s or less.

  That is, in the example, the plating layer was formed even when the scanning speed at the time of laser light irradiation was 50 mm / s, which is 5 times the 10 mm / s of the comparative example. By irradiating laser light in a direction orthogonal to the orientation direction of the glass fibers of the molded sheet, a plating layer is continuously formed even when the applied energy per unit area is 1/5 of the comparative example. It means that. The result of this example confirms that there is an effect of promoting the plating reaction according to the present invention even under conditions where the plating reaction hardly occurs.

An example of the molded object which has the electrically conductive circuit of this invention is shown, (a) is a top view, (b) is explanatory drawing of the electrically conductive circuit of (a). It is a perspective view which shows the other example of the molded object which has the electrically conductive circuit of this invention. . It is a graph which shows the threshold value of the irradiation condition of the laser beam of an Example. It is explanatory drawing of the molded object surface of a comparative example. It is a graph which shows the threshold value of the irradiation condition of the laser beam of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board 2 Glass fiber 3 Conductive circuit L Laser beam R The direction orthogonal to the orientation direction of glass fiber

Claims (7)

  A conductive circuit is formed by electroless plating in the region irradiated with laser light on the surface of a molded body formed from a mixture in which a non-conductive inorganic fiber and a copper-containing composite oxide material are added to a thermoplastic resin. A molded body having a conductive circuit, wherein the conductive circuit is formed in a direction crossing an orientation direction of the non-conductive inorganic fiber.   The molded article having a conductive circuit according to claim 1, wherein the thermoplastic resin is polybutylene terephthalate.   The molded body having a conductive circuit according to claim 1 or 2, wherein the non-conductive inorganic fiber is a glass fiber. The molded body having a conductive circuit according to any one of claims 1 to 3, wherein the copper-containing composite oxide material is spinel type CuCr ₂ O ₄ .   The molded body having a conductive circuit according to any one of claims 1 to 4, wherein the conductive circuit is formed in a direction orthogonal to the orientation direction of the non-conductive inorganic fibers of the molded body.   A compound in which a non-conductive inorganic fiber and a copper-containing composite oxide material are added to a thermoplastic resin is injection-molded, and a laser beam is applied to the surface of the resulting molded body in a direction crossing the orientation direction of the non-conductive inorganic fiber. A method for producing a molded body having a conductive circuit, wherein the molded body is subjected to electroless plating after irradiation and a conductive circuit is formed by electroless plating in a laser light irradiation region.   The method for producing a molded body having a conductive circuit according to claim 6, wherein the laser beam irradiation is performed with an average laser output of 1.3 W or more and an applied energy per unit area of 0.35 J or more.