JPH0577196B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a heat-resistant thermoplastic resin molded article having a large number of small holes for conduction between the front and back sides, which is manufactured using a hard resin mold that is a type of simple mold. This is a method of manufacturing a plastic molded printed wiring board in which a wiring network is formed by a known method, and is suitable for small-volume, high-mix production.

[Conventional methods and their problems]

The molds used to manufacture heat-resistant plastic molded products with small holes are ordinary metal molds or simple molds made of low-melting point metals, but these molds are complex and expensive. Therefore, there was a drawback that the heat-resistant plastic molded product was expensive.

The present invention solves the above problems and provides a method for manufacturing a heat-resistant plastic molded printed wiring board at a lower cost by easily manufacturing a mold capable of forming a wide variety of complicated small holes at a low cost and in a short time. This was completed after careful consideration.

[Means for solving problems]

That is, the present invention provides a front-back conductive printed wiring board in which a molded body for a plastic molded printed wiring board is formed with a large number of small holes for front-back conduction, and a conductor layer is formed on the molded body to create a wiring network. In the method for producing the molded article, the composition before curing has a property of being fluidized at a temperature of 100 ° C. or less,
It is made from a heat-resistant addition-polymerizable thermosetting resin composition with a glass transition temperature of 150°C or higher and containing 70% by weight or more of metal powder or metal fibers, and hard pins are embedded in the small holes. This method of manufacturing a plastic molded printed wiring board is characterized by using a molded body produced by molding a heat-resistant thermoplastic resin using a resin mold consisting of:

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, or a partially uneven board, which is made of solderable heat-resistant plastic and molded by compression molding or injection molding. Molded objects in shapes such as flat plates, curved plates, bent plates, etc. are subjected to surface swelling, oxidation, and other surface treatments using solvents as necessary, and known activation methods including Pd, Ag, Cu, etc. After activation with a chemical agent, electroless plating is performed to form a Cu or Ni layer on the surface, electrolytic plating is applied, a resist is applied as appropriate, and a pattern is baked and etched; after surface treatment, a known photoactive catalyst is applied. This is a printed wiring board in which a wiring network is formed by a method of selectively activating by irradiation with light and electroless plating only the activated portion; or by other known methods.

Here, heat-resistant plastics that can be soldered include heat-resistant thermoplastic resins such as polysulfone, polyetherimide, polyether sulfone, polyphenylene sulfide, polyphenylene ether, polycarbonate, polyphenylene ether, Thermoplastic resin such as polyacetal and cyanate ester compounds are mixed in 30/70 to 70/
Internetwork polymers (Japanese Unexamined Patent Publication No. 142297/1983) made by mixing at a ratio of about 30% and adding a catalyst, and these resins are appropriately reinforced with glass fiber, wollastonite, calcium carbonate, mica, etc. Examples include compositions to which base materials, fillers, etc. are added, and the heat resistance as is or after heat curing is such that it can withstand a soldering process at 260°C.

The mold of the present invention used to mold the above-mentioned molded article has the property that the composition before curing becomes fluid at a temperature of 100°C or lower, and the glass transition temperature of the cured resin is 150°C or higher. It is a resin mold made from a heat-resistant addition-polymerizable thermosetting resin composition containing 70% by weight or more of metal powder, and has hard pins embedded in the small holes.

First, as a heat-resistant addition polymerization type thermosetting resin whose composition before curing has the property of fluidizing at a temperature of 100°C or lower and the glass transition temperature of the cured resin is 150°C or higher, specifically, Cyanato resin (Special Publication 1977)
-1928, 45-11712, 44-1222, German Patent No. 1190184, etc.), cyanate ester-maleimide resin, cyanate ester-maleimide-epoxy resin (Japanese Patent Publication No. 54-30440, etc.) 52−
31279, USP-4110364, etc.), cyanate ester-epoxy resin (Japanese Patent Publication No. 46-41112), modified maleimide resin whose main components are polyfunctional maleimide, epoxy compounds, isocyanate compounds, etc. (Japanese Patent Publication No. 48-8279) No.), isocyanate whose main components are an isocyanate compound and an epoxy compound.
Examples include oxazolidone resin (JP-A-55-75418), polyfunctional epoxy resin whose main component is a trifunctional or higher polyfunctional epoxy compound, modified 1,2-polybutadiene resin, diallyl phthalate resin, silicone resin, etc. , cyanato resin (Special Publication Showa 41)
-1928, German Patent No. 45-11712, German Patent No. 44-1222, German Patent No. 1190184, etc.), cyanate ester-maleimide resin, cyanate ester-maleimide epoxy resin (Japanese Patent Publication No. 54-30440, etc., German Patent No. 52 −
31279, USP-4110364, etc.), cyanate ester-epoxy resin (Japanese Patent Publication No. 46-41112), etc., containing cyanate ester as an essential component are preferred. These thermosetting resins are appropriately combined with known additives for each resin, such as catalysts and curing agents such as amines, acid anhydrides, organic metal salts, and organic peroxides; Known silicone-based and fluorine-based mold release agents and waxes; flexibility agents such as diene rubber, low-crystalline to non-crystalline saturated polyester resins, and high-molecular-weight elastomers such as polyurethane; silicone Examples include well-known antifoaming agents and coupling agents such as A-type antifoaming agents.

The metal powder or metal fiber B of the present invention, which is blended into the above resin in an amount of 70% by weight or more, is mainly used for the purpose of imparting thermal conductivity to the resin mold, and is not particularly limited. For example,
These include iron, aluminum, copper, copper alloy, aluminum alloy, iron alloy, silver, etc.

The above ingredients are mixed at a temperature of 20 to 130°C using a roll, Banbury mixer, Henschel mixer, extruder, or other known kneading machine for a period of 1 minute to 10 hours, and kneaded when a uniform composition is obtained. After completion of the process, the heat-resistant addition polymerizable thermosetting resin composition of the present invention, which is in a viscous liquid or paste form at a temperature of 100°C or less, for example, about 50 to 90°C, is prepared and used for manufacturing a resin mold. use.

The resin mold of the present invention can be produced using a molding method in which this composition is used as it is or in combination with a reinforcing material as appropriate, using a desired model, cast, precured or cured, and optionally postcured. It is manufactured by post-processing and installing parts that are compatible with the system, such as gates.

The desired model is one that has the same shape as a molded object, such as a flat plate with many small holes for front and back conduction, a flat plate with partially uneven parts, a curved plate, a bent plate, etc. There is no particular restriction as long as it can withstand the mold and the heating during preliminary curing.

A typical example of the casting method is as follows: First, depending on the properties of the material of the model and the casting resin, a release agent is applied to the entire surface of the model, including the small holes, and dried. .

Process: Usually, in a container that can be vacuum-suctioned and heated as appropriate, a hardening paste-like material used for molding, such as plaster, is spread on a rectangular plate to a predetermined thickness. After fitting the model prepared in the process tightly onto the hard pin to be attached with the fixed side facing upward, insert a small hole into the model with the same diameter as the small hole with the ends protruding from both sides of the model and the resin. Attach a hard pin to one side of the mold so that it is sufficiently fixed, surround the sticky material with a rectangular column-shaped plate, harden the sticky material, and place a plate on top of it for cooling the mold. Place a metal pipe, etc. as a medium flow path.

Process: Pour the heat-resistant addition-polymerizable thermosetting resin composition of the present invention from above, degas or defoam by vacuum suction, and then apply a molding pressure of 0 to 30 Kg/cm ² and a temperature of 60°C or higher and 180°C or lower. In particular, it is heated and pressurized in a range of about 60 to 150°C to gel or semi-cure or harden it to make it self-retentive.

Process: Remove from the container, completely remove the hardened glue, apply a mold release agent to the model and casting resin surface, and prepare a metal plate of approximately 1 to 10 mm with a hole of the same diameter as the hard pin. After setting the mold and metal rods for reinforcement, placing it again in the container used in the process, and placing a metal pipe etc. as a medium flow path for mold cooling on top of it, the heat-resistant addition polymerization process of the present invention is carried out. The thermosetting resin composition is poured from the top of the mold, and after degassing or defoaming by vacuum suction, it is made self-retaining in the same manner as in the process.

Process: Since the resin mold obtained above is usually not completely cured, it is post-cured to obtain a hardened resin mold. The post-curing conditions are appropriately selected depending on the heat-resistant addition polymerizable thermosetting resin composition of the present invention to be used, but for example,
Cure in a constant temperature bath for about 20 hours.

Process: Post-process and attach gates and other parts.

It is.

In the above process, the split mold was cast in two stages, gelled or semi-cured or hardened, but the casting container was filled with a model, hard pins, medium flow path, etc. It is also possible to use a method in which parts such as gates and a thin film for releasing the mold are set, and the molding is performed in one casting.

Using the resin mold manufactured by the above method,
The heat-resistant thermoplastic resin described above is molded to form a molded body for a plastic molded printed wiring board of the present invention.

Molding depends on the conditions of the solderable heat-resistant thermoplastic resin used, but the molding cycle is usually such that the temperature of the side of the resin mold used that is in contact with the molded object does not exceed the glass transition temperature of the resin in the resin mold. The cycle is longer than that of metal molds.

〔Example〕

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

Example 1 Creating a model 100 small holes with a hole diameter of 0.9 mm were opened in a grid pattern at a pitch of 2.54 mm in a 50 mm x 50 mm and 2 mm thick glass cloth base epoxy resin laminate, and a fluorine-based mold release agent (product name;
Daifree MS-743 (manufactured by Daikin Industries, Ltd.) was applied and dried.

Preparing the casting mold for the moving resin mold A 30 mm thick paste made of a mixture of plaster and vinyl acetate was spread on a 100 mm x 100 mm plate, and the model was placed tightly in the center. rear,
A high-spin rod with a diameter of 0.9 mm and a length of 4 cm is inserted into a small hole so that the protrusion length from the model is 30 mm, and a 5 mm thick polycarbonate plate is made with and without holes for the entry and exit of the cooling copper pipe. The object was erected to a height of 130 mm to form a box shape, and a mold release agent was applied to the inner surface. Next, a cooling copper pipe having an inner diameter of 5 mm and bent several times into a U-shape was placed around this high spin, and the cooling medium flow path was placed so as to be drawn out from the above-mentioned entrance/exit hole.

Production of cast-like heat-resistant addition-polymerizable thermosetting resin composition After mixing 30 parts of 2,2-bis(4-cyanatophenyl)propane and 70 parts of 150 mesh aluminum powder in powder form, the mixture was heated to 80°C. The mixture was heated and stirred for 5 minutes to obtain a fluid composition (hereinafter referred to as composition A1).

25 parts of bisphenol A type epoxy resin (trade name: Epicote 828, viscosity 120-150 PS at 25°C, epoxy equivalent 184-194, manufactured by Yuka Ciel Epoxy Co., Ltd.) in which 0.03 part of iron acetylacetonate was dissolved in advance;
It was mixed with 75 parts of 300 mesh copper powder at room temperature to obtain a fluid composition (hereinafter referred to as curing agent B1).

75 parts of A1 and 25 parts of B1 obtained above were melted and mixed at 60°C to form a casting resin composition (hereinafter referred to as R1).
And so.

Casting on the movable side and casting on the fixed side Heat the R1 prepared above to 60℃, pour it into the above casting mold until all of the high spin is embedded, and vacuum it to 3 mmHg at 60℃ to defoam for 1 hour. After that, it was heated at 60°C for 10 hours to gel the casting resin.

Then, after removing the contents from the polycarbonate box and removing all the hardened sticky material,
Place the casting resin on the bottom surface of the polycarbonate box, apply the same mold release agent as used above to the inside surface of the polycarbonate box, the casting resin, and the entire surface of the model, and apply the same mold release agent for cooling. After placing the copper pipe, casting, vacuum degassing, and heating gelation were performed again in the same manner as above.

Post-curing and post-processing After opening the mold cast above and taking out the model, it was cured in a constant temperature bath at 180°C for 10 hours. Furthermore, the glass transition temperature of the cured product of the casting resin used in the mold is
The heat distortion temperature was 175°C and 200°C.

Next, a gate for injection molding and the like was fabricated on this cured resin mold, and this was fixed to a metal holder with casting resin R1 to obtain a resin mold for injection molding.

Manufacture of molded article The resin mold obtained above was set in an injection molding machine, and polysulfone resin (manufactured by Union Carbide, product name;
P-1700) was molded at an injection pressure of 1200 Kg/cm ² , a cylinder temperature of 340° C., and a molding cycle of 2 minutes while cooling the resin mold.

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 10 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 a 20 μm thick copper layer was deposited by thick electroless copper plating, followed by photoetching. This resulted in a double-sided conductive printed wiring board.

Example 2 In Example 1, 30 parts of bis(4-maleimidophenyl)propane and 60 parts of the same bisphenol A type epoxy resin as in Example 1 were used as a heat-resistant addition polymerizable thermosetting resin composition for casting. and diphenylmethane diisocyanate (trade name: MDI-CR,
50 parts of Mitsui Toatsu Chemical Co., Ltd.) were mixed uniformly, 400 parts of 150 mesh aluminum powder and 0.5 part of 2-ethyl-4-methylimidazole were added to this mixture, mixed at 60°C, and cast. A resin (hereinafter referred to as R2) was obtained.

A resin mold was obtained in the same manner using R2 above, except that an aluminum plate was used in place of the polycarbonate plate for the box, and the gelation temperature was changed to 170°C.
The glass transition temperature was 220°C.

Example 3 In Example 1, 30 parts of bis(4-maleimidophenyl)propane and 70 parts of the same bisphenol A type epoxy resin as in Example 1 were used as a heat-resistant addition polymerization type thermosetting resin composition for casting. and 120℃, 30
After mixing for a minute, the mixture was cooled to 50° C., and 5 parts of dichlorodiaminodiphenylmethane, 0.5 parts of dicumyl peroxide, and 300 parts of iron powder were mixed to obtain a casting resin (hereinafter referred to as R3).

Using R3 above, use an iron plate instead of the polycarbonate plate for the box, and set the gelling temperature to 160
A resin mold was obtained in the same manner except that the temperature was changed to ℃. The glass transition temperature was 200°C.

Example 4 In Example 1, 25 parts of diallyl phthalate prepolymer and 75 parts of diallyl phthalate monomer were used as a heat-resistant addition polymerization type thermosetting resin composition for casting.
After uniformly mixing at 80℃, cool and add copper powder.
350 parts were mixed uniformly, and then 2 parts of t-butyl peroxybenzoate were mixed at 40°C for 20 minutes to obtain a casting resin (hereinafter referred to as R4).

Using R4 above, use an iron plate instead of the polycarbonate plate for the box, and set the gel temperature to 150.
A resin mold was obtained in the same manner except that the temperature was changed to ℃. The glass transition temperature was 160°C.

Example 5 As a casting model, 50 small holes with a hole diameter of 0.7 mm were drilled in a grid pattern at a pitch of 2.54 mm on a 50 mm x 30 mm and 3 mm thick acrylic resin plate, and a fluorine-based mold release agent (product name: Daifree) was used. MS-743, manufactured by Daikin Industries, Ltd.)
A resin composition for casting was prepared by coating and drying the resin composition, using a 0.7 mm diameter high-spin, and placing copper pipes similar to those in Example 1.
2,2bis(4-cyanatophenyl)propane27
part, bis(4-maleimidophenyl)methane 3
150 mesh of stainless steel powder and 0.5 part of wax were mixed in powder form, and heated and stirred at 80°C for 5 minutes to obtain a fluid composition.
Example except that a casting resin composition (hereinafter referred to as R2) was prepared by melt-mixing 75 parts of curing agent B1 and 25 parts of curing agent B1 obtained in the same manner as in Example 1 at 60°C. A resin mold having a glass transition temperature of 178°C was obtained in the same manner as in 1.

The resin mold obtained above was set in an injection molding machine, and polyether sulfone resin (manufactured by ICI, USA, product name:
420P) was molded at an injection pressure of 1300 Kg/cm ² , a cylinder temperature of 350° C., and a molding cycle of 2.5 minutes while cooling the resin mold.

[Operation and effects of the invention]

The method for manufacturing a plastic molded printed wiring board of the present invention as described above uses a hard resin mold instead of a metal mold, so the mold is extremely easy to create, and the resin mold is heat resistant. (Tg,
It has excellent properties such as thermal deterioration) and abrasion resistance, as well as excellent workability, making it possible to produce a wide variety of products in small quantities at an extremely low cost and with high productivity compared to conventional metal molds. This opens up new uses for plastic molded printed wiring boards.

Claims (1)

[Claims] 1. In a method for manufacturing a printed wiring board with front and back conductivity, which involves creating a molded body for a plastic molded printed wiring board in which a large number of small holes are formed for front and back conduction, and forming a conductor layer on the molded body to create a wiring network. , as the molded article, the composition before curing has the property of being fluidized at a temperature of 100°C or lower, the cured resin has a glass transition temperature of 150°C or higher, and contains 70% by weight or more of metal powder or metal fiber. Using a molded body made from a heat-resistant addition polymerizable thermosetting resin composition, using a resin mold with hard pins embedded in the small holes, and molding a heat-resistant thermoplastic resin. A method for producing a plastic molded printed wiring board characterized by: