JPH0447996B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a printed circuit board, and more specifically, the present invention relates to a printed circuit board that has excellent heat resistance, particularly soldering heat resistance, can be used even at high temperatures, has high mechanical strength, and has high mechanical strength. The present invention relates to a novel printed circuit board that can be made thinner and has stable electrical properties. [Technical background of the invention and its problems] Printed circuit boards have conventionally been made using the surface of a composite sheet made of a combination of a thermosetting resin such as epoxy resin or phenolic resin and a base material such as paper or glass fiber. A metal layer provided on the surface is used. However, the above-mentioned thermosetting resin has the disadvantage that a solvent is also used when handling it, resulting in a poor working environment, and furthermore, it takes a long time to cure the resin, making it unsuitable for industrial use. In order to solve the above problems of thermosetting resins, printed circuit boards using thermoplastic resins such as crosslinked polyethylene and polyphenyl sulfide instead of thermosetting resins have been proposed. However, for example, the heat distortion temperatures of the two thermoplastic resins described above are 135° C. and 260° C., respectively, so they have poor solder heat resistance and are difficult to use in high-temperature environments. As described above, even if a thermoplastic resin is used, its applications are considerably limited since printed circuit boards are often used in high-temperature environments. [Objective of the Invention] The present invention solves the above-mentioned problems, has excellent heat resistance, especially soldering heat resistance, can be used even under high temperatures, has high mechanical strength, and has a thin substrate. The purpose of the present invention is to provide a printed circuit board that is capable of providing stable electrical properties. [Summary of the Invention] The present invention provides a printed circuit board having the following formula: (In the formula, Ar is

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[Formula] Represents one of the following. ) An insulating substrate that is a composite of 15 to 85% by weight of polycyanoaryl ether containing 80 mol% or more of repeating units represented by the formula and 15 to 85% by weight of glass fiber, and a metal provided on the surface of the insulating substrate. It is characterized by consisting of layers. First, the polycyanoaryl ether, which is a component of the insulating substrate in the present invention, contains 80 mol% or more of repeating units represented by the above formula (). The content of repeating units shown in formula () is 80
If the amount is less than mol%, the heat resistance and mechanical strength of the obtained insulating substrate will decrease. In addition to the repeating unit represented by the formula (), the polycyanoaryl ether used in the present invention has the following formula: (In the formula, Ar' represents a divalent aryl group different from the aryl group in the formula ().) Even if it is a copolymer containing 20 mol% or less of at least one repeating unit represented by good. As Ar′ in formula (),

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Examples include [Formula]. If the copolymerization component of the repeating unit represented by formula () exceeds 20 mol %, the heat resistance and mechanical strength of the obtained insulating substrate will decrease. This polycyanoaryl ether was prepared at 135% in a 70 mg/dl solution in N-methylpyrrolidone
It is suitable that the number average molecular weight in terms of polystyrene measured by high temperature gel permeation chromatography at °C is in the range of 20,000 to 90,000. This is because if the molecular weight is less than 20,000, heat resistance will be insufficient, and if it exceeds 90,000, it will be difficult to form a composite with glass fiber, which will be described later. Preferably, the number average molecular weight is 25,000 to 70,000. The above polycyanoaryl ether is produced, for example, as follows. That is, dihalogenobenzonitrile and

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The alkali metal salt of any of the divalent phenols of [Formula] may be dissolved in a solvent such as N-methylpyrrolidone or sulfolane, reacted at a predetermined temperature, and then treated with water or alcohol. . In addition, when polycyanoaryl ether is used as a copolymer, two or more types of dihydric phenols may be used. The blending amount of the polycyanoaryl ether in manufacturing the insulating substrate is 15 to 85% by weight. If the amount is less than 15% by weight, the polycyanoaryl ether will not be sufficiently dispersed in the gaps between the glass fibers, and if it exceeds 85% by weight, sufficient heat resistance and mechanical strength will not be obtained. Next, the glass fiber that is one component of the insulating substrate may be any glass fiber that is commonly used as a reinforcing material. The type and form of the reinforcing material are not particularly limited. For example, the form thereof may be a chopped fiber, a chopped fiber mat, a continuous filament mat, a woven fabric, a knitted fabric, etc., and a combination of these forms may be used. The amount of glass fiber added to the insulating substrate is usually 15 to 80.
The weight percent is preferably 20 to 70 weight percent. The amount of compounding
If it is less than 15% by weight, the heat resistance and mechanical strength will be insufficient, and if it exceeds 85% by weight, it will be difficult to form a homogeneous composite with the polycyanoaryl ether. The method for producing an insulating substrate made of a composite of the polycyanoaryl ether and glass fiber is as follows: (1) A method of mixing polycyanoaryl ether and short glass fiber (chopped fiber) and compression molding the mixture. (2) A method in which powder or pellets of polycyanoaryl ether is uniformly spread on a mat or fabric of long glass fibers and then compression molded; (3) A method in which polycyanoaryl ether pellets are extruded, compression molded, etc. A method of manufacturing a sheet, laminating this polycyanoaryl ether sheet with a long glass fiber mat or woven fabric, and compression molding the same. (4) Methods (1), (2), and (3) above as appropriate Examples include methods of combining. In addition, in any case of (1), (2), or (3),
There is no problem in adding appropriately known additives such as antioxidants, heat stabilizers, crystal nucleating agents, ultraviolet absorbers, and fillers to polycyanoaryl ether. Next, the constituent metals of the metal layer formed on the surface of the insulating substrate obtained by the above method are as follows:
Examples include copper, aluminum, nickel, and silver. These metals are usually used as metal foils when applied to printed circuit boards, but are not limited thereto, and may be formed from plating liquid in the additive method described below, for example. Methods for forming the metal layer on the insulating substrate include (1) a subtractive method in which the insulating substrate and the metal foil are bonded together using, for example, an adhesive, and then pattern etched according to a desired circuit pattern; Commonly known methods are applied, such as (2) the stamping foil method, in which metal foil is previously punched into the desired circuit pattern, and (3) the additive method, in which metal is plated in the desired circuit pattern on an insulating substrate. can. [Examples of the invention] Example 1 (1) Production of polycyanoaryl ether In an autoclave with an internal volume of 5, 137.6 g (1.25 mol) of hydroquinone, 215 g (1.25 mol) of 2,6-dichlorobenzonitrile, and potassium carbonate were added.
207g (1.5mol), sulfolane 2.5, toluene
1.5 and reacted in an argon stream at 160°C for 1.5 hours and then at 200°C for 1.5 hours. After the reaction was completed, a large amount of water was injected to obtain polycyanoaryl ether powder. The obtained powder was further washed with hot water and methanol, and then dried. As a result, the yield of polymer is
260g (yield 100%), the number average molecular weight of the polymer is 44000, and the following formula:

The content of the repeating unit represented by the formula was 100 mol%. Regarding the thermal properties of this polymer, it had a glass transition temperature (Tg) of 180°C, a melting point (Tm) of 340°C, and a thermal decomposition onset temperature (Td) of 520°C (in air). (2) Manufacture of printed circuit board Extrusion molding is performed using the polycyanoaryl ether pellets described above, and the wall thickness is set to 0.5 so that the content of polycyanoaryl ether in the insulating board is the value shown in the table. Two mm sheets (50 mm x 50 mm) were manufactured. Next, two sheets of the above polycyanoaryl ether were used to make glass continuous fiber mat (manufactured by Asahi Fiberglass Co., Ltd.: CSM,
M9600) one sheet was sandwiched. Next, the whole was fed into a 50mm x 50mm flat plate mold heated to 390℃, heated and compressed for 4 minutes at a pressure of 6Kg/cm ² G, and then transferred to a cooling press set at 250℃ to form a mold of 30Kg/cm. Cooling was performed under a pressure of ² G for 5 minutes. As a result, a composite sheet with a wall thickness of 1.1 mm was obtained. Next, this composite sheet is used as an insulating substrate, and after bonding this insulating substrate and electrolytic copper foil with an epoxy resin adhesive, heat and pressure treatment is performed to create a printed circuit where the copper foil and insulating substrate are integrated. A substrate for use was obtained. Regarding the obtained printed circuit board, the heat distortion temperature (based on ASTM-D648), bending strength (based on ASTM-D790), peel strength of copper foil (based on JIS-C6481), dielectric constant, and dielectric loss tangent (based on ASTM -Compliant with D150.Measurement frequency: 10 ³ Hz). Example 2 As polycyanoaryl ether, 2,6-
The following formula uses dichlorobenzonitrile and 4,4'-biphenol as starting materials: It has 100 mol% of the repeating unit shown in
A printed circuit board was manufactured in the same manner as in Example 1, except that polycyanoaryl ether having a Tm of 360°C and a Td of 540°C was used, and measurements were conducted in the same manner. Example 3 As polycyanoaryl ether, 2,6-
The following formula uses dichlorobenzonitrile and 2,7-dihydroxynaphthalene as starting materials:

It has 100 mol% of repeating units represented by the formula, has a number average molecular weight of 36,000, and has thermal properties of Tg 215°C.
A printed circuit board was manufactured in the same manner as in Example 1, except that polycyanoaryl ether with a Tm of 340°C and a Td of 505°C was used, and the temperature during press molding was 400°C, and measurements were conducted in the same manner. Example 4 A printed circuit board was produced in the same manner as in Example 1, except that the glass fiber content was slightly more than twice that in Example 1, and measurements were performed in the same manner. Comparative Example 1 A printed circuit board was manufactured in the same manner as in Example 1, except that the content of glass fiber was 10% by weight, and measurements were performed in the same manner. Comparative Example 2 A printed circuit board was manufactured in the same manner as in Example 1, except that a thermoplastic resin, polyether ether ketone (manufactured by Imperial Chemical Industries), was used as the resin component, and measurements were performed in the same manner. The above results are summarized in the table.

[Table] [Effects of the Invention] As is clear from the examples of the invention, the printed circuit board of the present invention is made of polyether, which has been known to have the best heat resistance and soldering heat resistance. It has heat resistance comparable to that of a substrate using etherketone, and has superior mechanical strength. Therefore, the substrate can be made thinner and lighter and smaller. Such excellent heat resistance allows printed circuit boards to be used at high temperatures. As described above, the printed circuit board of the present invention has excellent heat resistance, soldering heat resistance, use at high temperatures, mechanical strength, and electrical properties, so it can be used in home appliances, electronic computers, communication devices, etc. Since it is useful when applied to measuring instruments, etc., its industrial value is great.

Claims (1)

[Claims] Primary formula: (In the formula, Ar represents any one of [Formula] [Formula] [Formula].) 15 to 85% by weight of polycyanoaryl ether containing 80 mol% or more of the repeating unit represented by [Formula] and glass fiber 15 1. A printed circuit board comprising: an insulating substrate that is a composite of 85% by weight and a metal layer provided on the surface of the insulating substrate.