JPS6364392A - Manufacture of plastic-molded printed wiring board - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a method of manufacturing a printed wiring board using a plastic molded body having a large number of through holes produced by injection molding, and is particularly an economical method. This method uses a mold for injection molding, and can be suitably applied to high-mix, low-volume production.

[Conventional methods and their problems]

Conventionally, the molds used for manufacturing heat-resistant plastic molded products with through-holes are ordinary mold steel (ordinary mold steel molds or simple molds made of low-melting point metals). .

Conventional steel molds have a disadvantage in that they have a large number of pore-machined parts that are extremely difficult in terms of machining, precision, and cost. In addition, in the case of a low melting point metal, it is essential that the through hole is formed into a mold in which a hard pin is embedded and fixed, but there is a drawback that the fixed hard pin is likely to loosen due to heat or pressure.

The present invention solves the above problems and manufactures a low-cost heat-resistant plastic molded printed wiring board by easily manufacturing a mold capable of forming various types of complicated through holes at a low cost and in a short time. This was completed after intensive study on how to do this.

Means for Solving Problem C] The present invention involves injection molding heat-resistant plastic to create a plastic molded body having a large number of through holes, and forming a conductor layer on the molded body to manufacture a printed wiring board. In this method, as a mold for producing a molded body, a fixed metal mold plate having at least a molten resin introduction part and a space for mounting a mold part, which communicates with the fixed metal mold plate as necessary, is used. An injection molding die center comprising a stripper metal template having a molten resin introduction part and a space for mounting the mold part, and a movable metal template forming a space for mounting the mold part. A pair of metal molds consisting of a prepared metal mold ■ in which a recessed part for a cavity was formed and a metal mold II in which a through hole for forming a hole and a movable pawn pin and a recessed part for a cavity were formed as desired; In addition, a hard pin type III is prepared by fixing the hole-forming hard pin with a curable composition. An injection molding mold formed by fixing the molds to the movable metal mold plate and assembling them in this order, or (b), hard pin mold III to the fixed metal mold plate and metal mold II to the stripper metal mold plate. This is a method for manufacturing a plastic molded printed wiring board, characterized in that a metal mold I is fixed to a movable metal mold plate, respectively, and an injection mold formed by assembling in this order is used, and in a preferred embodiment, In the case of hard pin type III, metal type I and metal type II are stacked on the side of the cavity with metal type II as the top surface, a hard pin is attached to this, and a release layer is provided on the surface of metal type (■). It is made by casting a curable composition and curing it, and furthermore, it is made by using a thermosetting resin composition for hard resin molds as the curable composition used for this casting.

The present invention will be explained below.

The plastic molded printed wiring board of the present invention is a flat plate having a large number of small holes for front and back conduction and other holes formed by injection molding using solderable heat-resistant plastic, or a partially uneven board. Molded objects in the shape of a certain number of strips, one strip with a curved surface, a bent plate, etc. are subjected to surface swelling, oxidation, and other surface treatments with a solvent as necessary to produce products containing Pd, Ag, Cu, etc. After activation with a known activator, Cu is deposited by electroless plating or vapor deposition.
A method of forming a HI layer selectively or on the entire surface, electrolytically plating as appropriate, applying a resist, baking a pattern, and etching; After surface treatment, a known photoactive medium is applied and selectively irradiated with light. This is a printed wiring board in which through-holes and wiring networks for front and back conduction are formed using a method of activating the substrate and electroless plating only the activated portion; or other known methods.

Heat-resistant plastics that can be soldered include heat-resistant thermoplastic TL resins such as polysulfone, polyetherimide, polyether sulfone, polyphenylene sulfide, polyphenylene ether, polyester-based and other liquid crystal polymers; polycarbonate, polyphenylene ether, etc. thermoplastic resin, polyfunctional unsaturated compounds, low molecular weight 1,2-polybutadiene neck, epoxy resins, and cyanate ester compounds. Internetwork polymers (JP-A-1986-1999) are made by mixing IJ necks, other thermosetting monomers, etc. in a ratio of usually about 70 to 30%, and adding catalysts such as organic peroxides and organic metal salts. 142297), etc.; glass fiber, wollastonite, calcium carbonate, etc. are added to these resins as appropriate.
Composition made by adding mica, other reinforcing base materials, fillers, etc.'! yJff; Examples include epoxy resin, phenol resin, cyanate resin, and other injection moldable thermosetting resin molding materials, and the heat resistance as is or after heat curing is sufficient to withstand the soldering process at 260"C. belongs to.

The mold of the present invention for producing a molded article by injection molding the above-mentioned resin includes a fixed metal mold plate forming at least a molten resin introduction part and a space for mounting a mold part, and optionally A stripper metal mold plate having a molten resin introduction part communicating with the fixed metal mold plate and forming a space for mounting the mold part, and a movable metal mold having a space for mounting the mold part. Prepare an injection molding die set consisting of a plate,
If desired, the receiver of the hard pin for forming a hole for a plastic molded body is made of a metal mold (2) in which a recess for a hole and a cavity is formed, a through hole for movable a hard bottle for forming a hole, and a recess for a cavity if desired. A pair of metal molds consisting of metal mold II and a hard pin mold III in which the hole-forming hard pin is fixed with a curable composition are created, (a), metal mold I is fixed to the metal mold plate on the fixed side, The metal mold II is fixed to the stripper metal mold plate, and the hard pin mold III is fixed to the movable metal mold plate, respectively, and the injection molding mold is assembled in this order, or (b), the hard pin mold III is fixed to the fixed metal mold plate. Place metal type II on the stripper metal template and metal type I on the movable side joint.
This is an injection mold made by fixing each to a bent mold plate and assembling in this order.

Here, Guiset refers to ordinary metal materials for molds - iron,
A pair of metal type I, ■, and hard pin type III for the cavity, respectively, consisting of a temporary made of iron alloy or other metal.
A space or hole of a predetermined size is provided in advance for fixing.

In particular, the stripper metal plate is installed to prevent "gauling" caused by poor vertical and horizontal alignment when the mold is opened and closed during injection molding.

The pair of metal molds I and ■ for the cavity may be made of ordinary metal materials, but aluminum alloys such as duralumin are preferred from the viewpoint of workability and strength, and are usually 5 to 3Q thick.
The metal type I usually has a recess for a cavity for the plastic molded body and, if desired, a hole for a hard pin for forming a hole with a depth of 1 to 5 mm at a predetermined position. . In addition, the metal mold H fixed to the stripper metal mold plate was provided with a through hole at a predetermined position for movable a hard pin for forming the hole.

In addition, the hard pin type (■) is usually made by aligning and fixing a pair of metal molds I and II for the cavity as described above, applying a mold release agent to the surface of the metal mold (2), and inserting a hard bottle. rear,
A method of manufacturing by temporarily fixing, casting a curable composition, curing, gelling, or pre-curing, removing metal types I and II, and heating to completely cure; After aligning and fixing the pair of metal molds ■ and II for the tee, and aligning and arranging the metal plate with the through hole in the same position as the through hole, insert the hard bottle. It is manufactured by the method of fixing using the curable composition described above.

Any curable composition can be used as long as it has a certain degree of heat resistance, including heat-resistant plasters, cements, plastic refractories, low melting point alloys, and thermosetting resin compositions. For example, compositions for hard resin molds, which are a type of thermosetting resin compositions, are preferred from the viewpoint of handleability, impact resistance, curing shrinkage, and the like. Suitable resin compositions for hard resin molds include cyanate ester resin compositions, modified maleimide resins containing polyfunctional maleimide and epoxy compounds, isocyanate compounds, etc. as main components (Japanese Patent Publication No. 48-8279); Isocyanate-oxazolidone resin (Japanese Patent Application Laid-open No. 75418/1983), which mainly consists of isocyanate compounds and epoxy compounds, epoxy resins, modified 1,2-polybutadiene resins, diallyl phthalate resins, silicone resins, etc., as well as metal powders and metals. It is preferable that fibers, inorganic fillers, etc. are usually blended in a range of 65 to 15% by volume, and the glass transition temperature after curing is 100°C or higher, particularly 150°C or higher, and
Those having fluidity at a temperature of 100° C. or lower are suitable.

In addition, hard bottles are made of iron, stainless steel, high-speed steel, etc., and are usually 0.111Iφ or more, and have a convex part with a larger diameter on one end to make the fixation stronger. In order to improve mold releasability from the molded resin, a material with fluororesin baked onto the surface of at least a portion of the mold cavity is appropriately used.

Using the mold elements described above, the mold of the present invention is assembled, set in an injection molding machine, and heat-resistant plastic is injection molded to obtain a molded body for a plastic molded printed wiring board.

Injection molding conditions and other conditions are appropriately selected depending on the type of plastic used. In addition, it is easy to fabricate a part of the mold cavity with a reference mark part for forming a wiring network, a reinforcing part, a frame, a mounting part for a printed wiring board, etc., as appropriate. , metal type),■,
Created as an addition to the resin-fixed coin bottle type■.

Furthermore, there are various injection molds depending on the type of gate, and the invention can be applied to these as appropriate.

〔Example〕

The present invention will be explained below with reference to Examples. In addition, parts in the examples are based on weight unless otherwise specified.

Preparation of the die set As the fixed side metal template, 9011 x 9Q with a depth of 15+u for fixing the resin warming part and the metal mold l for the cavity.
A steel plate with a thickness of 40mw with +u square holes was used as a stripper metal template, and a steel plate with a thickness of 1Qmm with a 9On + As such, a 401 mm thick iron field temporary was prepared with a hole of 85+uX85 mm square and a depth of 1511 mm for fixing a hard bottle fixing type (■).

These metal templates naturally have sprues, runners, and other parts for introducing molten resin, fixing parts for assembling and fixing them to the mold, guide bin bushings, and other parts, just like those used in ordinary molds. The auxiliary jig part was formed.

Preparation of metal mold for cavity Made of aluminum alloy (90 fins x 9Qnm square) with a thickness of 10mm (
Prepare two sheets of paper, and place a 2mm deep hole in the center of one sheet.
A metal mold for a cavity (2) was prepared by carving a square of X5Qmm×5Qm and further carving a gate part in the center.

In the other plate, 100 through holes of 0.92 miφ were bored at the same positions as described above, and a metal mold II for the cavity was produced.

Furthermore, the hard bottle type (2) was manufactured by a method using a resin composition for hard resin molds.

First, the resin composition for hard resin mold is 2.2-bis(4-
A composition was obtained by mixing 30 parts of a prepolymer obtained by heating and stirring (cyanatophenyl) propane at 150°C for 3 hours and 70 parts of 150 mesh aluminum powder.

Bisphenol A type epoxy resin (trade name: Epicoat 828, viscosity 120-150 PS at2
It was prepared by mixing 25 parts of 5°C1 epoxy (1184-194, manufactured by Yuka Shell Epoxy ■) at 60°C.

Layer the metal molds I and II for the cavity prepared above on one side of the cavity with metal mold II as the top surface, and insert a high-speed steel bottle of length 25 mm x O, 9 (bmφ) into the hole of the metal plate ■. After temporarily fixing with cyanoacrylate,
Apply a silicone resin mold release agent to the surface other than the bottle, and
Made of polycarbonate board 351m x 86n x 100 +
The frame of u (height) was aligned and fixed.

Next, the above resin composition for a hard resin mold was cast at 60°C, held for 4 hours while degassing under vacuum to gel the resin, and the metal mold I for the cavity, ■ and the frame were removed. ,
It was cured in a constant temperature bath at 175° C. for 8 hours and processed to produce a hard pin type III measuring 85 mm x 85 mm x 15 mm (casting part thickness).

Assembling the mold and manufacturing the molded body: Place the metal mold I on the fixed side metal template of the die set obtained above.
The metal mold II was assembled and fixed to the stripper metal template, and the hard bottle mold III was aligned to the movable metal template.

The stripper metal plate was attached to the movable metal plate, and the hard pins were placed so that they did not come out of the cavity surface of the stripper metal template at all when the mold was opened.

Place the above mold into an injection molding machine and add polysulfone resin (manufactured by Union Carbide, product name: P-1700).
Pressure 1.200 kg/cn), cylinder temperature 3
Molding was performed at 40°C and a molding cycle of 20 seconds.

Manufacture of plastic molded printed wiring board The molded body obtained above was immersed in a mixed solution of 50% by volume of 35% hydrogen peroxide and 50% by volume of 98% sulfuric acid at 40°C for 110 minutes, neutralized, and washed with water.

After drying the molded body, the entire surface was activated with palladium using a tin chloride and palladium chloride solution, and then a 20-thick copper layer was deposited using a thick electroless copper plate. Furthermore, after applying a photodegradable angry photoetching resist to the entire surface of the precipitate, a pre-prepared 1M negative film for formation was set, and after irradiating it with ultraviolet rays and making it angry,
Remove the bright spots, remove the exposed copper using a known etching method,
The resist was peeled off^1 to obtain a double-sided conductive printed wiring board.

[Operation and effects of the invention]

As explained above in the detailed description and examples, the manufacturability of the plastic molded printed wiring board of the present invention is such that the die set includes a metal mold 1 for the mold cavity, a metal mold for movable hard bottles, and a hard pin resin. This method fixes a fixed mold to create a cavity for the intended molded body for a plastic molded printed wiring board, so the through-hole mold, which is difficult to manufacture,
It is easy to create one with good accuracy.

Due to the above characteristics, plastic molded printed boards can be produced more economically and quickly, and can be produced in large quantities in small quantities at an extremely low cost compared to conventional metal molds.
Productivity is something that can be done. Furthermore, in addition to the small holes for double-sided conduction, it is also easy to provide reference marks for making wiring networks, mounting parts, and other auxiliary parts in a part of the mold cavity, increasing the degree of freedom in design, etc. This opens up new uses for plastic molded printed wiring boards with good productivity and finish.

Claims (1)

[Scope of Claims] 1. A method for producing a printed wiring board by injection molding heat-resistant plastic to create a plastic molded body having a large number of through holes, and forming a conductive layer on the molded body. As a mold for use, a fixed-side metal mold plate forming at least a molten resin introduction part and a space for mounting the mold part, and, if necessary, a molten resin introduction part connected to the fixed-side metal mold plate, is used. An injection molding die set consisting of a stripper metal template forming a space for mounting the mold part and a movable metal template forming a space for mounting the mold part is prepared. A pair of metal molds consisting of a metal mold I with a concave portion formed therein and a metal mold II with a through hole for movable hard pin for hole formation and a concave portion for a cavity if desired, and the hard pin for hole formation. A hard pin type III fixed with a curable composition is created, (a) Metal type I is used as the fixed side metal template, metal type II is used as the stripper metal template, and hard pin type III is used as the movable side metal template. An injection molding mold formed by fixing the hard pin mold III to the fixed metal mold plate and assembling it in this order, or (b), fixing the hard pin mold III to the fixed metal mold plate, and assembling the metal mold II in this order.
A method for manufacturing a plastic molded printed wiring board, characterized in that a metal mold I is fixed to a stripper metal template, metal mold I is fixed to a movable metal template, and an injection mold is used which is assembled in this order. 2. The hard pin type III overlaps the metal type I and metal type II on the side of the cavity with the metal type II as the top surface, attaches the hard pin to this, provides a release layer on the surface of the metal type II, and hardens. 2. The manufacturing method according to claim 1, which is obtained by casting and curing the adhesive composition. 3. The manufacturing method according to claim 1 or 2, wherein the curable composition is a thermosetting resin composition for a hard resin mold.