JPS63164391A - Printed wiring board - Google Patents

Abstract

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

Description

[Detailed description of the invention] Ritachi ■Plate]! The present invention comprises at least a conductive metal and an insulating substrate,
The invention relates to a printed wiring board characterized in that the insulating substrate is a crosslinked product obtained by irradiating a thin mixture of a copolymer of two types of ethylene and a monomer having a polar group with an electron beam, The object of the present invention is to provide a printed wiring board in which the insulating substrate not only has good heat resistance but also has extremely good adhesion to conductive metals.

Recent electronic devices are rapidly becoming smaller, lighter, thinner, and more densely packaged. In particular, printed wiring boards began to be commercialized for use in consumer devices such as radios, televisions, washing machines, and compact discs, and are now used in telephones, facsimile machines, word processors, robots, and computers, supported by mass production and high reliability. Applications are expanding to office equipment such as machines and industrial equipment.

In addition, flexible printed wiring boards were initially used as an alternative to electric wires and cables, but their flexibility not only allows for high-density three-dimensional mounting in narrow spaces, but also because they can withstand repeated bending. Its use is expanding as a composite component that provides wiring, cable, and connector functions for the moving parts of electronic devices.

Currently, the materials used as three-dimensional wiring materials in devices such as cameras, electric desktop calculators, telephones, and printers are:
A wiring pattern is formed using a flexible copper-clad board in which electrolytic copper foil of 35 microns is adhered to both or one side of a polyimide or polyester film with a thickness of about 25 microns. A wiring pattern in which through-hole plating is applied, and both sides and the outer layer are coated with a coverlay is also used.

Current flexible printed wiring boards generally use polyimide or polyester resin films as base materials, but polyester films not only have poor solder heat resistance, but also are difficult to bond with conductive metal layers such as copper foil. The epoxy adhesive used in this product has a high water absorption rate and is
Since the coefficient of thermal expansion is large at temperatures ranging from 250° C. to 250° C., through-hole connection reliability is lacking. Furthermore, when manufacturing 1
Curing is sometimes carried out by steam press at 70° C., and when multi-layered, not only does the adhesiveness between the resins decrease, but also the flexibility tends to decrease.

On the other hand, polyimide film is soldered at the normal soldering temperature (26
Polyimide resin has the advantage of being able to easily perform solder connections at temperatures above 0°C.

In addition to its hygroscopicity, it also has the disadvantage of poor surface activity, which makes it very difficult to adhere to metal foils.

In order to solve this problem of adhesion, the surface of the film is generally treated chemically using caustic soda, a chrome mixture, aluminum hydroxide, etc., and then bonded using an adhesive. method is being carried out. However, even when bonding is done using these methods,
It is not possible to obtain a printed wiring board with sufficient adhesion, and it has poor chemical resistance, heat resistance, water resistance, etc., and has drawbacks such as copper foil lifting due to etching treatment and solder flow.

In addition, thermosetting adhesives with excellent heat resistance (for example,
In the method of bonding with metal foil using epoxy resin,
Polyimide film coated with adhesive must be layered with metal foil and cured using heat and pressure in a press for 1 to 20 hours, which poses problems in terms of productivity, mass production, and cost. Furthermore, due to its high hygroscopicity, it is necessary to dehydrate it under heat and reduced pressure before the soldering process.

For these reasons, a part of the present invention provides a conductive metal and a metal plate such as aluminum, a ceramic plate, an aramid am, and a thermosetting resin (e.g., epoxy The insulating substrate is made of a copolymer of ethylene and an unsaturated dicarboxylic acid, its anhydride ring or halfester, and a non-containing material having an epoxy group capable of radical copolymerization with ethylene. We have previously proposed printed wiring boards or flexible printed wiring boards that are crosslinked products of mixtures of copolymers with saturated monomers (Japanese Patent Applications No. 130-149193, No. 81-24089, No. 8).
No. 1-94837, No. 81-104854, etc.), these printed wiring boards and flexible printed wiring boards not only have good heat resistance and chemical resistance, but also have low water absorption, and can be easily manufactured. However, these printed wiring boards and flexible printed wiring boards do not always have satisfactory adhesion with other materials such as polyimide and conductive metals at relatively high temperatures.

But −. From the above, the present invention does not have these problems (defects), that is, it not only has excellent heat resistance and chemical resistance, but also has low water absorption and relatively high temperature (for example, 100
The purpose of this invention is to have excellent adhesion to other substances such as polyimide and conductive metals at temperatures (°C), and to easily obtain printed wiring boards (including flexible printed wiring boards).

. - and according to the present invention, these problems are solved by at least a conductive metal and an insulating substrate.

The insulating substrate is (^) at least a unit derived from ethylene and at least one monomer selected from the group consisting of α, β-unsaturated monocarboxylic acid, α, β-unsaturated dicarboxylic acid, anhydride thereof, and halfester. and (B) a mixture consisting of a copolymer (II) consisting of at least units derived from ethylene and units derived from an ethylenically unsaturated monomer containing an epoxy group. It is a crosslinked product obtained by irradiating a thin material with an electron beam, the mixing ratio of copolymer (I) in the mixture is 10 to 80% by weight, and the carboxyl group in the mixture and a printed wiring board characterized by .

It can be solved by The present invention will be explained in detail below.

The copolymer (I) used in the present invention contains at least units derived from ethylene and α, β-, β-monocarboxylic acid, α, β-, β-dicarboxylic acid.

It is a copolymer comprising a unit derived from at least one monomer selected from the group consisting of the anhydride and Hafestel. Examples of the copolymer include the following polymers.

(1) Copolymer of ethylene and α, β-unsaturated monocarboxylic acid [hereinafter referred to as “ethylene copolymer (a)”] (2) Copolymer of ethylene and α, β-, β-monocarboxylic acid ester A copolymer obtained by saponifying part or all of the copolymer and performing a neutralization reaction such as demetalization of the part or all using an acid etc. [hereinafter referred to as "ethylene copolymer (b)"] ] and (3) ethylene and α,β-unsaturated dicarboxylic compounds.

Its anhydride or its copolymer with Hafestel [hereinafter referred to as "ethylene copolymer (C)"] These copolymers (I) melt at a temperature of 150°C or less and have fluidity. desirable.

(A) Ethylene copolymer (a) Ethylene copolymer (a) contains at least ethylene and α,
It is a copolymer with β-unsaturated monocarbonate, and in order to ensure the above-mentioned fluidity properties, a radically polymerizable comonomer having a polar group (hereinafter referred to as the "third component") is copolymerized. Preferably.

By copolymerizing this third component as a comonomer, a multicomponent copolymer having units derived from the monomer corresponding to the third component copolymerized into the ethylene copolymer (a) can be obtained (see below). The same applies to the ethylene copolymers (b) to ethylene copolymers (d)).

The number of α,β-unsaturated mononorboxylic acids that can be used in the production of this ethylene copolymer (a) is generally 3 to 20 (II, preferably 3 to 10). Examples include acrylic acid, methacrylic acid, crotonic acid, heptanoalkyl maleate, heptanoalkyl fumarate, and the like.

Further, the third component is a radically polymerizable vinyl compound containing a polar group, and representative examples include unsaturated carboxylic acid esters, vinyl esters, and alkoxyalkyl (meth)acrylates.

The number of carbon atoms in the unsaturated carboxylic acid ester is usually 4 to 40, and 4 to 20 carbon atoms are particularly preferred. Representative examples include carbon atoms with good thermal stability such as methyl (meth)acrylate and ethyl (meth)acrylate. Those with poor thermal stability such as t-butyl (meth)acrylate are not preferred because they cause foaming.

Furthermore, the alkoxyalkyl (meth)acrylate usually has at most 20 carbon atoms. Further, the Jlji' prime number of the alkyl group is 1 to 8 (preferably.

Representative examples of preferable alkoxy(meth)alkyl acrylates include those having 1 to 4 carbon atoms, and more preferably those having an alkoxy group having 1 to 8 carbon atoms (preferably 1 to 4 carbon atoms). Mention may be made of ethyl acrylate, ethoxyethyl acrylate, and butoxyethyl acrylate. Furthermore, vinyl esters generally have at most 20 carbon atoms (preferably 4 to 16 carbon atoms), and typical examples thereof include vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl vivalate. .

In the ethylene copolymer (a), the amount of the third component is 2
It is preferably 5 mol% or less, and particularly preferably 2 to 20 mol%. Even if it exceeds 25 mol%, the characteristics of the present invention are expressed, but it is not necessary to exceed 25 mol%, and from the viewpoint of production and economy. Undesirable.

Ethylene copolymer of α,β-unsaturated monocarboxylic acid (
The amount of bonding in a) is preferably 0.5 mol% or more and 25 mol% or less, particularly preferably 1.0 mol% to 15 mol%. Although block or random copolymers are available, random copolymers are particularly preferred.

The α,β-unsaturated monocarboxylic acid is used as a crosslinking reaction site with the ethylene copolymer (d) and epoxy resin described later, and to provide adhesiveness with a wide variety of base materials. There is no need to be excessive from a superficial perspective.
If the amount increases, water absorption will increase, which will not only have negative effects such as deterioration of electrical properties due to foaming during molding and water absorption after molding, but will also cause manufacturing problems such as safety and separation φ recovery, and economical problems. On the other hand, it is disadvantageous and undesirable.
If it is less than 0.5 mol %, there will be no problem in terms of adhesiveness, but it is not preferable because it will be insufficient in terms of heat resistance.

The ethylene copolymer (a) is a mixture of ethylene and an unsaturated carboxylic acid, or a mixture of these and a third component.
~2500Kg/crn' ultra-high pressure, 120~
Using a chain transfer agent if necessary at a temperature of 260°C.

Obtained by radical polymerization using a free radical generator such as peroxide in an autoclave or tubular reactor equipped with a stirrer, or by graft copolymerization of an unsaturated carboxylic acid in the presence of a free radical generator if necessary. be able to.

(B) Ethylene copolymer (b) Furthermore, the ethylene copolymer (b) used in the present invention is one of the ester groups in the ethylene copolymer consisting of ethylene and an unsaturated carboxylic acid ester. It is a copolymer obtained by saponifying part or all of it and performing a neutralization reaction such as demetalization treatment.

The unsaturated carboxylic acid ester usually has 4 to 40 carbon atoms, with 4 to 20 carbon atoms being particularly preferred.6 A typical example is methyl (meth)acrylate.

Examples include ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, and diethyl fumarate.

The content of unsaturated carboxylic acid ester in the ethylene copolymer (b) is preferably 1 to 25 mol%. conversion rate, in terms of carboxylic acid-containing units in the copolymer after neutralization treatment.

0.5 to 20 mol% is preferred, particularly 1 to 15 mol%.

The saponification reaction can be carried out using a widely known method, such as a mixed solvent of toluene and isobutyl alcohol (mixing ratio 5G).
: 50) by adding NaOH and a copolymer containing an ester group and refluxing for 3 hours. The saponification rate can be arbitrarily adjusted by adjusting the amount of NaOH. Furthermore, this saponified product is precipitated with water or alcohol, and after filtering the solvent, it is vacuum-dried at 50°C day and night. The ethylene copolymer (b) is obtained by dispersing this polymer in water, adding sulfuric acid thereto, and stirring the mixture at 70° C. for 1 hour to perform a metal removal treatment (=neutralization reaction).

(C) Ethylene copolymer (c) Also, the ethylene copolymer (C
) may result in a copolymer of ethylene and an α,β-unsaturated dicarboxylic acid, its anhydride, or its monoester (which may also contain the third component),
That is, it is a direct copolymerization of ethylene, α,β-unsaturated dicarboxylic acid, its anhydride or its halfester, or these and the third component.

Examples of the third component include the same type of compound as the ethylene copolymer (a).

When the ethylene copolymer (C) is produced by a direct copolymerization method, an α,β-unsaturated dicarboxylic acid.

Its anhydride or its halfester is selected as the copolymerizable fumonomer.

The α,β-unsaturated dicarboxylic acid usually has at most 20 carbon atoms, preferably 4 to 16 carbon atoms. Typical examples of the dicarboxylic acid include maleic acid,
Fumaric acid, itaconic acid, citraconic acid, 3.8-endomethylene-1,2,3,8-tetrahydro-cis-2
Tallic acid (nadic acid@) is an example.

As α,β-unsaturated dicarboxylic acid hafester,
The number of carbon atoms is generally at most 40, especially 5 to 20.
I can give you individual things. A typical example thereof is one in which one of the carboxyl groups of the dicarboxylic acid is /\-phesterified with a representative example of the alcohol described below. Typical examples of the alcohol include general alcohols having at most 20 carbon atoms, such as methanol, ethanol, propatool, and butanol. Typical examples of Hafestel include maleic acid monomethyl ester, maleic acid monoethyl ester, maleic acid monoisopropyl ester, maleic acid monobutyl ester, and itaconic acid monoethyl ester.

The bond amount of "α,β-unsaturated dicarboxylic acid or its halfester" (hereinafter referred to as "unsaturated dicarboxylic acid component") in the copolymer (c) is 0.5 mol% or more and 20 mol% or less. It is preferable that there is, more preferably 1.0
~15 mol%.

The copolymer (II) used in the present invention is an ethylene copolymer [hereinafter referred to as "ethylene copolymer"] consisting of at least units derived from ethylene and units derived from an ethylenically unsaturated monomer containing an epoxy group. d).

(D) Ethylene copolymer (d) The ethylene copolymer (d) contains at least ethylene and "
It is a copolymer with an "unsaturated monomer having an epoxy group capable of radical copolymerization" (hereinafter referred to as "epoxy compound"). Furthermore, a multicomponent copolymer obtained by copolymerizing ethylene and an epoxy compound with the third component can also be used for the same reason as above.

Representative examples of this epoxy compound include those whose general formulas are represented by the following formulas [Formula (1) and Formula (II)].

Typical examples of epoxy compounds represented by formulas (I) and (II) include glycidyl methacrylate, glycidyl acrylate, α-methylglycidyl acrylate, α-methylglycidyl methacrylate, vinyl glycidyl ether, allyl glycidyl ether, and Examples include methallyl glycidyl ether.

The melt index (JIS K-
7210, temperature is 180℃ and load is 2.1
(Measured at 8Kg, hereinafter referred to as "Ni, 1.") are usually 0.5 g / 10 minutes or more, and 5.0 g 7
The heating time is preferably 10 minutes or more, particularly 50 g and 710 minutes or more.

To produce the mixture of the present invention, at least one of the ethylene copolymers (a) to ethylene copolymers (c) and the ethylene copolymer (d) are mixed in the following mixing ratio range. However, by further mixing the reaction accelerator or organic peroxide described below, the ethylene copolymer (a
), ethylene copolymer (b) and ethylene copolymer (C) and ethylene copolymer (d)
can promote crosslinking.

(E) Reaction accelerator The reaction accelerator used in the present invention is widely known as a curing agent for epoxy resins, and a representative example is Hiroki Kakiuchi's "Epoxy Resin" (Shokodo, (Published in 1978) pages 26 to 29, pages 32 to 35, pages 109 to 128, and 1111
Examples include those described on pages 5 to 188, pages 330 and 331.

Typical examples of this reaction accelerator include primary, secondary, or tertiary amines, acids, and alkaline compounds represented by formula (m), and ammonium salts represented by formula (IV). .

In formula (III) and formula (mV), nj R? ,
R8 and R8 may each be the same or different, and are a hydrocarbon group selected from a hydrogen atom, an alkyl group having 1 to 32 carbon atoms, an aryl group, an alkaryl group, and an aralkyl group, but at the same time, they are not all hydrogen atoms. ,X
is a halogen atom. In these formulas, R6 to R8 are preferably hydrocarbon groups in which the major prime numbers are 12 or less.
Further, X is preferably a chlorine atom or a bromine atom.

Typical examples of the reaction accelerator include ethanolamine, jetanolamine, triethanolamine, dimethylamine, diethylamine, n-propylamine, isopropylamine, n-butylamine, M,N-dimethylaminoethanol, N,N- Diethylaminoethanol, morpholine, piperidine, pyridine, N, N-
Dimethylaminoethyl acrylate, N,N-dimethylaminomethacrylate, N,N-diethylaminoethyl acrylate, trimethylamine, triethylamine, tri-n-butylamine, N,N-dimethylbenzylamine, hexamethylenetetramine, triethylenediamine, N,N-dimethyl Tertiary amines such as piperazine and N-methylmorpholine, acidic or alkaline compounds such as p-toluenesulfonic acid and potassium hydroxide, and trimethylbenzylammonium chloride, tetraethylammonium bromide, tetrabutylammonium chloride and cetyltrimethylammonium chloride. Examples include ammonium halogen salts and zinc chloride. Particularly preferred is N,N-dimethylbenzylamine toluenesulfonic acid.

In producing the mixture of the present invention, the copolymer (I) is a copolymer consisting of units derived from ethylene and units derived from α,β-unsaturated dicarboxylic acid anhydride, that is, ethylene and α,β-unsaturated dicarboxylic acid anhydride. When using an unsaturated dicarboxylic acid anhydride or an ethylene-based multicomponent copolymer consisting of these and the third component, it is an organic compound or polymer with a boiling point of 150°C or higher, and a hydroxyl group (-〇H
By blending (mixing) those having a copolymer (I group) or a carboxyl group (-COO)I group), crosslinking between the copolymer (I) and the copolymer (rl) is promoted.

The polymer includes the ethylene copolymer (a),
Ethylene copolymer (b), ethylene copolymer (c)
Among them, units derived from ethylene, α, β-unsaturated monocarboxylic acid, α. Copolymers with units derived from monomers selected from the group consisting of β-unsaturated dicarboxylic acids and halfesters thereof (these copolymers may be ethylene-based multicomponent copolymers containing a third component), Saponified copolymers of ethylene and vinyl acetate, copolymers of ethylene and hydroxyalkyl (meth)acrylates, and polymers (including homopolymers) whose main component is ethylene or propylene, as well as the above ethylene copolymers. Union (a)
and a modified olefin polymer obtained by graft polymerization of the α, β-unsaturated monocarboxylic acid, α, β-unsaturated dicarboxylic acid, or anhydride thereof used in producing the ethylene copolymer (C). can be given.

Furthermore, examples of organic compounds include ethylene glycol, polyethylene glycol, propylene glycol, glycerin, and polypropylene glycol.

(F) Mixing ratio The mixing ratio of the ethylene copolymer (a) to ethylene copolymer (C) in the mixture of the present invention is 10 to 90% by weight as their total amount, and 15 to 80% by weight. is preferred, particularly 20 to 85% by weight.

Even if the mixing ratio of ethylene copolymer (a) to ethylene copolymer (c) in the mixture is less than 10% by weight or more than 80% by weight as a total amount, the crosslinking property of the mixture may vary depending on the composition ratio. is insufficient, and the resulting crosslinked product has poor heat resistance.

In addition, the carboxyl group (-〇〇〇H) of the ethylene copolymer (a) to ethylene copolymer (C) in the mixture
and carboxylic acid anhydride groups is preferably 3/1, particularly preferably 0.5/1 to 2/1. Even if carboxyl groups are present in the mixture, adhesion to metals at high temperatures is poor.

When producing the mixture of the present invention, when blending the above-mentioned organic compound and/or polymer having a hydroxyl group or carboxyl group, the mixing ratio thereof should be the above-mentioned copolymer (1), copolymer (II) and epoxy It is usually at most 20 parts by weight based on 100 parts by weight of the total amount with the resin, preferably 0.1 to 20 parts by weight, and 0.5 parts by weight.
-20 parts by weight are preferred, especially 1.0-15 parts by weight.

In addition, when one reaction accelerator is added, the mixing ratio is 0.005 to 5.0 parts by weight, and 0.01 to 5.0 parts by weight.
Parts by weight are preferred, especially 0.0! ~2.0 parts by weight is preferred. Even if more than 5.0 parts by weight of the reaction accelerator is blended, the effect of promoting low-temperature crosslinking will be expressed, but not only will this reaction accelerator itself inhibit crosslinking adhesion, but the reaction accelerator may also cause molding. This is undesirable because it causes bleeding on the surface of the object, making it impossible to obtain a good molded product.

Furthermore, when adding an organic peroxide, the mixing ratio is generally o,oot~10.0 parts by weight, and 0.00 parts by weight.
5 to 1060 parts by weight is preferred, especially 0.01 to 7.0 parts by weight.
Parts by weight are preferred. If more than 10.0 parts by weight of organic peroxide is added, crosslinking will occur rapidly and it will be difficult to control crosslinking.

(G) Preparation of Mixtures The mixtures of the present invention may be prepared by using one or more copolymers (I
) [i.e., selected from ethylene copolymer (a), ethylene copolymer (b) and ethylene copolymer (c)] and copolymer (II) (i.e., ethylene copolymer ( d)] or these and an organic compound or polymer having a hydroxyl group or carboxyl group, as well as a reaction accelerator or organic peroxide (hereinafter referred to as the ``mixed component''). Conductivity is I x 10-3 cal/”O#c
m*m or more, and the electrical resistance value is 1010Ω・am
When the thin-walled product obtained by blending the above inorganic filler is relatively thin, thermal conductivity can be improved.

Representative examples of such inorganic fillers include beryllium oxide, boron nitrogen, magnesium oxide (magnesia), aminium oxide (alumina), silicon carbide, and glass beads. Furthermore, the particle size of the powder of the inorganic filler is preferably 1 particle size of 100 #L or less, and particularly preferably 0.1 to 20 mm.
If it is less than pm, it is difficult to uniformly disperse it in the resin composition. On the other hand, 100. Exceeding this limit is undesirable because the resin layer becomes thicker and the adhesive strength also decreases.

The blending ratio of this inorganic filler is at most 70% by volume. If the thickness of this insulating layer is thin (for example, 20 ILm or less), the thermal conductivity will improve even if it is not filled (blended) with an inorganic filler, so there is no need to specifically blend it. Because of this, it is limited to applications with low voltage resistance. Generally, the thicker the insulating layer, the better the insulation, but the lower the thermal conductivity, so inorganic fillers are more effective. from these things.

When the thickness of the insulating layer (resin layer) is in the range of 10 to 30 ILm, the blending ratio of the inorganic filler is preferably 50% by volume or less.
Also, the thickness is 30gm to 4. In the Os layer range, 2
The ratio of the inorganic filler in the resin layer is preferably 0 to 70% by volume, and if it exceeds 70% by volume, the thermal conductivity of the resin layer will improve, but it will not interact with the other substances and conductive metals described below. This is not preferable because not only the adhesiveness of the resin layer decreases, but also the resin layer (insulating layer) may break during bending or drawing, resulting in cracking.

The mixing method may be tri-blending using a mixer such as a Henschel mixer, which is commonly used in the field of olefin polymers, or melt-kneading using a mixer such as a Banbury, extruder, or roll mill. can give. At this time, a more uniform mixture can be obtained by triblending in advance and melt-kneading the resulting mixture. When melt-kneading, it is necessary that the mixed components do not undergo a substantial crosslinking reaction (if crosslinking occurs, the moldability will not only deteriorate when the resulting mixture is molded as described later), but also the desired molded product (This is undesirable because it may cause a decrease in heat resistance when crosslinking the shape or molded product.)
Therefore, the melt-kneading temperature depends on the type and viscosity of the ethylene polymer and epoxy resin used, but is preferably room temperature (20°C) to 150°C, preferably 140°C.
The following are preferred.

As a guideline for this "substantially no crosslinking", the total amount of copolymer (I) and copolymer (II) is "extracted in boiling toluene for 3 hours, and then the diameter is 0.IJL theory or more. Generally, it is preferable that the residual aroma (hereinafter referred to as "extraction residual") is 15% by weight or less, and 10% by weight.
The following is preferable, and 5% by weight or less is optimal.

In producing this mixture, in order to further improve heat dissipation (thermal conductivity) and insulation,
Moreover, by filling the inorganic filler with high thermal conductivity, the effects of the present invention can be further exhibited.

(H) Production of thin-walled products To produce thin-walled products from the mixture obtained as described above, the T-Guy film method and inflation method, which are commonly used in the field of thermoplastic resins, are widely used to produce films. It can be obtained by extruding it into a film or sheet using a conventional extruder. At this time, if extrusion is carried out at a high temperature, part or all of the mixed components will crosslink and small gel-like particles will be generated, making it impossible to obtain a uniformly thin product. The temperature is usually 250°C or lower. In particular, it is preferable to carry out the process in the same temperature range as in the case of melt-kneading described above.

In any of the above cases, after producing the thin-walled article, a good thin-walled article can be obtained by rapidly cooling it in a water-cooling roll or a water bath to prevent adhesion between the thin-walled articles or between the thin-walled articles and a take-up roll or the like. The thickness of the thin material obtained in this way is 5 mm to 4.0 mm, preferably 10 mm to 3.0 mm, and especially 20 to 50 mm thick.
Peng Peng is preferred.

It is preferable that the thin-walled product obtained in this way is not crosslinked, that is, the extraction residue is preferably 15% by weight or less, as described above, preferably 10% by weight or less, and particularly preferably 5% by weight or less.

(J) Conductive metal Methods for obtaining the conductive metal of the present invention include a method using a metal or alloy foil as described below, a method of vapor depositing a metal, a method of electroless plating, and an electroless plating method. An example of this method is to use a combination of the method and the electrolytic plating method.

(1) Foil The foil metal and alloy is aluminum.

Examples include metals such as gold, silver, iron, copper, nickel, and platinum, and alloys containing these as main components (50% by weight or more) (for example, stainless steel).

The thickness of this foil is usually 5 to 500 tons, and lθ to 30
0 JLII is preferable, especially 15-110
07t is suitable. Among the metals and alloys mentioned above, electrolytic copper foil with a thickness of 15 to 50 JLm is preferably used.

(2) Vapor deposition As a method for vapor depositing the metal, commonly used vacuum heating vapor deposition such as resistance heating, electron beam heating, conducting heating, or thermal radiation heating, or sputtering can be applied. Particularly for fine circuits, platinum and gold are often used, and when forming a circuit by etching after forming a thin film, copper, aluminum, and alloys containing these as main components are preferably used.

The thickness of the deposited conductor thin film can be freely selected depending on the conditions of the equipment used, but is usually between 100 angstroms (Ions) and 100 IL11.
, and the distance b is 1000λ (100r+m) or 2
0 lm is desirable.

In addition, copper is deposited on the conductive surfaces (paths) of these evaporators.

It is also possible to electroplate or solder plate a metal such as nickel or gold to protect the surface and prevent corrosion, or to apply solder on the conductive path through a solder bath.

A so-called full additive method is also possible in which one circuit is formed by vapor deposition on the inner surface of the through hole of the metal or alloy plate by the vapor deposition carried out in the present invention.

In addition, the conductive metal layer can be manufactured by using an electroless plating method or a combination of an electroless plating method and an electrolytic plating method as described in detail in Japanese Patent Application No. 80-99.

In manufacturing the printed wiring board of the present invention, a crosslinked product obtained by crosslinking a thin product of the above-mentioned mixture as described below can be obtained by providing a conductive metal on at least one side of the crosslinked product. It is common to provide a layer of other material on the substrate.

Other materials include metal plates, metal foils, #thermal resins, heat-resistant fiber moldings, ceramics, and thermosetting resins. These other substances are not special and are widely used in the field of printed wiring boards (including flexible printed wiring boards).

(K) Metal plate and metal foil The metal types of the metal plate and metal foil include plates of metals such as aluminum, copper, and iron, and alloys containing these metals as main components (for example, stainless steel). The thickness of the metal plate is generally 0.5 to 5.0 mm, particularly preferably 1.0 to 5.0 mm, and metal foil usually has a thickness of 5 to 500 mm (preferably, 30 to 500 ILs+, preferably 50 to 500 ILs+)
Moreover, heat dissipation can be improved by providing unevenness on the surface (outer surface) of the metal plate. The specific surface of the metal plate at this time is 1.1 or more, especially 1.8
The above is desirable.

Examples of methods for increasing the specific surface include methods using mechanical processing (for example, cutting processing and scorching processing) and methods using chemical processing (for example, alumite processing).

(L) Heat-resistant resin Also, examples of the heat-resistant resin include polyimide, saturated polyester, and other heat-resistant polymer substances.

Polyimide is generally obtained by casting and drying a polyimide acid solution obtained by a low-temperature solution polymerization method, and then subjecting it to a dehydration ring-closing reaction. Polyamideimide having an amide group can also be preferably used. The general formula of the polyimide is shown in formula (m), and the general formula of polyamide-imide is shown in formula (IT).These polymers are used as heat-resistant resins used in printed circuit boards.
"Electronic Materials" August 1879 issue, page 251.

It is a polymer compound containing an ester bond 11 and has an aromatic ring in the polymer chain unit. Aromatic dicarboxylic acid or its ester-forming derivative (which may be substituted with at most 40 mol% aliphatic dicarboxylic acid or alicyclic dicarboxylic acid) and aliphatic diol having 2 to 20 carbon atoms or ester formation thereof It is a polymer or copolymer obtained by a condensation reaction containing as a main component a glycol derivative (at most 50 mol % of which may be substituted with a long chain glycol having a molecular weight of 400 to e, ooo). The intrinsic viscosity of this polyester is usually 0.4 to 1.5 (preferably) when measured at 30°C using a mixed solvent of phenol and tetrachloroethane in a ratio of 1:1 (by weight).

Typical polyesters are polyalkylene terephthalate resins, which are widely used as polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate.

Other heat-resistant polymer substances include glass transition temperature (
Examples of heat-resistant polymers having a rTgJ (hereinafter referred to as rTgJ) of 200 to 4000C include those having the following polymer skeletons. For those with an amide bond as the backbone,
For example, poly-m-xy p-benzamide (Tg 230°C or higher), terephthalamide (Tg 345°C), which is a polycondensate of xylene diamine and adipine, and υ~m-phenyleneisophthalamide CTg2s.

Examples include polyoxybisphenol A, a condensate of polyarylate p-hydroxybenzoic acid obtained by polycondensing bisphenol A and isophthalic acid chloride or terephthalic acid chloride, phosgene and isophthalic acid chloride or terephthalic acid chloride. There are condensation products such as aromatic polyester carbonates, and those with ether bonds as bones include polyoxymethylene [CH2-0]n, polyphenipolysulfone polyether ether ketone polyphenylene sulfide -=-0→S+. Polytriazine (Tg240-3
30°C), polyazomethine polyparabanate, polydistyrylpyrazine, etc.

These thin heat-resistant resins are generally used as films or sheets. The thickness of the thin material is usually 10g.
m to 2.0mm, and 20ILm to 2.0m
① is preferable, especially 50IL11 to 1.8+
US is preferred.

(M) Heat-resistant fibrous material Examples of the heat-resistant resin used in the present invention include sheet-like materials of aramid fibers, and cloth and nonwoven fabrics of glass.

Aramid tag is generally a fiber of polyamide C whose molecular skeleton is aromatic (hereinafter referred to as "aromatic polyamide"), and is distinguished from ordinary aliphatic polyamide fiber (nylon).

This aromatic polyamide has a general formula (V) with a linear molecular skeleton (hereinafter referred to as "aromatic polyamide (1)"), a para bond type (hereinafter referred to as "aromatic polyamide (1)"), and a (VT) formula with a zigzag-shaped meta bond type. Bond type [hereinafter referred to as “aromatic polyamide (2)”
] and the zigzag meta-bond type represented by the formula (■) [hereinafter referred to as "aromatic polyamide (3)"]
It is broadly divided into

The shape of am is plutifiment 2 (usually 1 to 3
denier length, circular cross section of 10 to 20 microns in diameter), non-woven fabrics made from this alone, cut fibers cut into 3 to 15 m lengths, and thickness of 1 micron or less and lengths of 2 to 5 cm. Examples include those produced in the form of surface fibrils using a centrifugal spinning method.

Regarding this aramid fiber, see "Plastics" by Sakai, Kamiyoshi, and Tada, Vol. 38, No. 3, pp. 20 to 45.
(1985).

The size of the jam is preferably as thin as possible in order to reduce unevenness on the surface of the printed circuit board, and is generally 10 IL11 or less, particularly preferably 1 IL11 or less.

In addition, this sheet-like material generally has a
0 g or more, preferably 10 g/m'' to 500 g/m'', particularly 20 g/rn'' to 50 g/m''
077/rrl is preferred.

Furthermore, regarding the glass 1ata and its sheet-like products and fabrics (eg, glass cloth, glass mat), those used in the glass NAm industry can be preferably used. In addition, it is desirable to use a material that has been subjected to a general sealing treatment, as well as a cleaning treatment or a silane treatment to improve compatibility with the synthetic resin used.

The crow cloth and glass mat l,%-(
In terms of flexibility and prevention of peeling from conductive metal and cracking when the molded product (printed wiring board) is bent, it is generally less than 300g per square meter.
A weight of 0 to 250 g is desirable, and a force of 50 to 200 g is preferred.

Regarding the shapes, manufacturing methods, types, etc. of the aramid fiber and glass fiber sheets and fibers, see Japanese Patent Application No. 1491/1980!
It is described in each specification of No. 178290.

These heat-resistant fibrous materials may be partially or completely impregnated into the crosslinked thin material of the mixture described later when producing a printed wiring board.

(N) Thermosetting resin Examples of thermosetting resins include phenolic resins, epoxy resins, and unsaturated polyester resins. The thickness of this substrate is 0.8 to 4.0 mm (preferably 0.8 to 3.0 mm).
2 m+e), and is made of glass fiber, such as stable short #I fiber, and has a weight of 2 m + e).
Laminating sheets of 0 to 200 g/rn' and 30 to 200 microns in thickness, asbestos fiber, organic fiber, carbon #! ! A material obtained by impregnating a fibrous material such as a male with a thermosetting resin to form an fjI layer can also be used.

Moreover, these fibrous materials can be used by mixing them with pulp by a wet paper-making method in the same way as ordinary paper. Furthermore, in order to improve the electrical properties of glass paper, epoxy resins, alkyd resins, ethylene-vinyl acetate copolymers, or thermosetting resins treated with so-called silane treatment to improve immersion may also be used. As a typical example of 0 that can be done, JI
Glass cloth base epoxy resin copper clad laminate JIS GE2, GE2F, GE4, GE4F shown in standards such as SC-8484, NEMA, NIL etc.
, paper-based phenolic resin copper-clad laminate (JISC-64
85) Paper-based epoxy resin copper-clad laminate (JIS
C-13482).

(0) Ceramics Types of ceramics include alumina (A text 203)
, silicon nitride (S i 3Na), silica (Si02)
, titanium nitride (TiN), titanium carbide (T i C)
, zirconium oxide (zirconia, Z ro2), A1
203-5 i02 series (mullite porcelain) Zr02/5i
02, beryllum oxide (Bed), magnesium oxide (magnesia, M g O), B a Ti O3,
5iTi03, boron nitride (BN), and boron carbide (B4C). Among these ceramics, alumina and silicon nitride are preferable. In particular, alumina is relatively inexpensive, and has good heat resistance, thermal conductivity,
It is preferably used because it not only has excellent mechanical strength, impact resistance, electrical insulation, and chemical durability, but also is easy to process.

In the present invention, these ceramics can be manufactured by firing these ceramics to form a plate shape, or by forming a thin film on the surface of a metal plate.

Chemical vapor deposition (CVD) is a method for forming thin films.
, vacuum evaporation method, sputtering method, thermal spraying method, etc.

In addition, the sintering method is determined based on the particle size distribution of the starting material ceramic, the agglomeration state, the influence of impurities, etc., the molding method, and the sintering temperature for 1 hour.

Various sintered products can be obtained depending on the sintering conditions such as the atmosphere. These sintering methods include one-reaction sintering method, pressure sintering method, (H
P method, HIP method), pressureless sintering method, gas pressure sintering method, etc. Furthermore, recently, injection molding methods have become popular for mass production. In this method, ceramic powder and an organic binder are generally mixed in advance, the resulting mixture is used to make a primary molded product using an injection molding machine, and the product is made into a product through a degreasing process and a main sintering process.

The methods for forming and sintering the thin film are industrially practiced and widely known.

The method for forming these thin films and the sintering method are described in detail in Japanese Patent Application No. 59-2813312.

The thickness of the ceramic substrate thus obtained varies depending on the method of forming the thin film and the method of firing. In the method of forming a thin film, generally 100s (10nm
) to 0.1 am, especially IILll to 1
007 is preferably layered, and in the firing method, it is usually 50 mm to 10 mm thick, and 0.1 mm to 10 mm thick.
1.5 mm is desirable.

In order to manufacture the printed wiring board of the present invention, when a metal foil is used among the conductive metals described above, a thin-walled product of the metal foil and the mixture produced as described above, or a thin-walled mixture of the metal foil and the above-mentioned mixture is used. The metal foil and other substances may be crosslinked by irradiating them with electron beams as described below.Also, when depositing or plating a conductive metal, the thin material of the mixture and other substances may be cross-linked. The material may be crosslinked by electron beam irradiation, and the resulting crosslinked product may be deposited or plated.

At this time, if a metal plate is used as the other material,
A laminate is made by irradiating a metal plate and a thin object or a conductive metal foil and a thin object with electron beams in advance, and in the case of the former, the conductive metal foil is heat-pressed onto the thin surface of the laminate as described below. However, it is necessary to deposit or plate a crosslinking or conductive metal. In the latter case, it is necessary to heat and press the metal plate onto the thin surface of the laminate while crosslinking it.

(P) Electron beam crosslinking Methods for carrying out the electron beam crosslinking include Cockcroft type, Cockcroft-Walton type, Nokundegraf type,
Methods include emitting electron beams from various types of electron beam accelerators, such as insulated core transformer type, linear type, dynamidron type, high frequency type, and electrocurtain type. @The tolerance can be varied within a wide range depending on the required performance of the irradiated object.

Generally 0.5-200 Mrad, 1.0
~200 Mrad is preferred, especially 1.0-150
Mrad is preferred. If the irradiation dose is less than 0.5 Mrad, the degree of crosslinking is insufficient. On the other hand, if it exceeds 200 Mrad, molecular cleavage occurs and the physical properties of the crosslinked product deteriorate.

In addition, the accelerating voltage is usually 50 to 3000 KV, 1
00 to 3000 is preferable, and V is particularly preferable to 100 to 800.

The atmosphere during crosslinking is preferably an inert gas, if necessary. Representative examples of this inert gas include nitrogen, carbon dioxide, helium, and the like.

The crosslinked product thus obtained may be further heat-pressed as described below.

(Q) Heat-press bonding method The heat-press bonding method is selected depending on the thickness of other materials, ease of manufacture, productivity, etc., but in general, heat press methods using a press molding machine and heat rolls are used. A typical example is a method of applying thermocompression bonding, which is generally practiced when manufacturing multilayered products.

With the heat press method, products with sufficient adhesive properties can be obtained even at heating temperatures of 30°C or higher; however, in cases where heat resistance is required, it is necessary to
It is preferable to carry out the pressure bonding at a temperature of 10 to 20 degrees Celsius higher than the required heat resistance temperature, thereby obtaining an A-layer board with good heat resistance and adhesiveness. At this time, the heating temperature is 100~
10-20 minutes at 180℃, 160-240℃
By heating and pressurizing for 0.5 to 10 min in the range of 240 to 400 °C, and 0.1 to 5 minutes in the range of 240 to 400 °C, a crosslinking reaction (1i! combination reaction) occurs within the resin, improving adhesiveness and heat resistance. Sexuality is markedly impaired. The pressurizing conditions are generally 0.1 Kg/ctn' (gauge pressure) or higher, preferably 1 to 100 Kg/cm'', especially 2
~20 Kg/cm'' is preferable. In order to obtain more uniform adhesion, a method of applying pressure with a slight load under vacuum and reduced pressure is also used.

Further, in the thermocompression bonding method, the laminated components may be laminated and thermocompression bonded at a temperature of 250° C. or higher.

In any of the above methods, each 11k layer component is temporarily bonded in advance (usually at 120 to 250°C), and then heated as described above! The crosslinking may be carried out while the film is being coated.

The extraction afterflame of the thin-walled material crosslinked in this manner is at least 60%, preferably 70% or more, and particularly preferably 75% or more.

(R) Printed wiring board and method for manufacturing the same The printed wiring board of the present invention is composed of at least a conductive metal and an insulating substrate (resin layer, cross-linked mixture), but as described above, it may contain layers of other substances ( It is common to provide a molded article). The mixture in the obtained printed wiring board needs to be crosslinked as described above. In the printed wiring board of the present invention, a layer of a crosslinked product of the mixture is provided between the conductive metal layer and the other material layer. It is necessary to intervene. Further, as shown in Figure 2-c below, the same applies to a case of a multi-layer stacked structure or a case of a conductive metal layer and a layer of another substance.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical example of a printed wiring board according to the present invention will be explained below with reference to the drawings. The following drawings are partially enlarged sectional views of representative examples of the printed wiring board of the present invention.

The printed wiring board shown in Figure 1-a has a conductive metal layer l.
A resin layer (thin material) 2 of the crosslinked product crosslinked with electron beam and other materials (for example, metals, ceramics, thermosetting resins, etc.)
It is obtained by sequentially laminating thick layers 3 of heat-resistant resin). The one shown in Figure 1-b is the first
An inorganic filler 5 is added to the resin layer 2 of the printed wiring board shown in FIG. The one shown in Fig. 1-c has conductive resin layers 1 laminated on both sides, and the first
Fig. 1-d is a partially enlarged sectional view of a typical example of the printed wiring board shown in Fig. 1-c provided with through holes 8. Figure 2-a shows a part of a printed wiring board obtained by sequentially laminating a conductive metal layer 1, a resin layer 2, a flexible metal foil, a film-like material 4 such as a heat-resistant resin or a heat-resistant resin. It is an enlarged sectional view. Fig. 2-b is a partially enlarged sectional view of the structure shown in Fig. 2-a with conductive metal layers l provided on both sides, and Fig. 2-c is a partially enlarged sectional view of the same as shown in Fig. 2-a.
FIG. 2 is a partially enlarged cross-sectional view of a typical example of a multi-layer board in which the components shown in FIGS.

What is shown in FIG. 3-a is one in which the inside of the resin layer 2 is filled with a heat-resistant fibrous material (for example, aramid cloth, glass cloth) 7. Fig. 3-b shows a case where a nonwoven fabric 6 is filled instead of the fibrous material shown in Fig. 3-a. What is shown in Figure 3-c is Figure 3-a or Figure 3-
The one shown in Figure b is a typical example when the thick layer 3 (or film-like material 4) of another material is used as the layer A, and the third-
Figure d is a partially enlarged sectional view when a film-like material 4 made of a heat-resistant resin is laminated on the intermediate layer of the resin layer 2, and the thick layer 3 (or the film-like material 4) is further laminated thereon.

These drawings are typical partially enlarged cross-sectional views of a laminate in which a resin layer (thin material) is used in the printed wiring board of the present invention, but in addition to this, the adhesion of the thin material, It is possible to combine them to take advantage of their insulation performance.

Moreover, as shown in FIG. 2-c, it is also possible to use it as a multilayer printed wiring board.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, in the examples and comparative examples, the peel strength is JIS
Conductive metal N (copper foil, etc.) in accordance with C-8481
The conductive metal layer was peeled off at 90 degrees (pulling speed: 50 mm/min), and the peel strength was measured. Further, the heat resistance was evaluated by floating it in a solder bath with a lead/tin ratio of 90/10 (weight ratio) maintained at 300° C. for 10 seconds, 20 seconds, and 180 seconds. The evaluation is shown in Table 1 as follows.

O: Unchanged in its original form X: Peeling and cracks between base insulating material and copper circuit 1
There was deformation such as cracking and separation.

In addition, molded products of various other substances, inorganic fillers, copolymer (I) and copolymer 1) used in Examples and Comparative Examples
The mixture with is shown below.

[(A) Mixture of copolymer (1) and copolymer (II)] Ethylene-acrylic acid copolymer with Ll of 300 g/10 min (density 0.954 g/crn)
”, copolymerization ratio of acrylic acid 2039g%, hereinafter referred to as rEAAJ) and ■, 120g/
Ethylene-methyl methacrylate glycidyl methacrylate terpolymer [copolymerization ratio of methyl methacrylate 18.6% by weight, copolymerization ratio of glycidyl methacrylate 12.7% by weight, hereinafter r GMA
(1) A mixture [referred to as J] [mixing ratio EA]
A/GMA ・(1) = 50150 (weight ratio), hereinafter referred to as "mixture (■)"], ■, is 21
Ethylene-maleic anhydride-ethyl acrylate ternary copolymer with a concentration of 0 g/lG (maleic anhydride copolymerization ratio 2.8 mol%, ethyl acrylate copolymerization ratio
8.5 mol%, hereinafter referred to as rETPJ) and the above G)IA (15) (mixture ratio ETP
/ (iN^(1) / EAA= 4015G/ 1
G (weight ratio), hereinafter referred to as "mixture (II) J", and an ethylene-glycidyl methacrylate-vinyl acetate copolymer in which the ETP and N, 1 are 7.2 g/10 min.
Copolymerization ratio of glycidyl methacrylate 2.3 mol%
, copolymerization ratio of vinyl acetate 2.0 mol%, hereinafter r GM
A (2) J] [Mixing ratio: E]
TP/GNA(2)-407GO (weight ratio), hereinafter referred to as "mixture (■)"] was used. In addition, the aforementioned EAA and GMA (1) were also prepared for comparison.

Note that these mixtures were manufactured by tri-blending the respective mixing components at each mixing ratio for 5 minutes using a Henschel mixer.

[(B) Molded product of other substances]

In addition, as molded products of other materials, commercially available epoxy resin glass cloth substrates (equivalent to JIS C-6484, GE 4, hereinafter referred to as "thermosetting substrates (A)"), commercially available paper phenolic resin laminates ( JIS C-8485, PP
7F equivalent product, hereinafter referred to as "thermosetting substrate (B)"], aluminum plate with a thickness of 1 inch (hereinafter referred to as "aluminum plate")
, a 0.5 m thick diametral steel plate, an alumina plate (thickness lam) obtained by sintering low soda alumina (Al2O2) described later, an aluminum foil (hereinafter referred to as "aluminum") with a thickness of 100 μm. 251Lm thick
Polyimide film [manufactured by Toshisha Co., Ltd., trade name: Kapton, thickness: 25 gm, hereinafter referred to as "Film (1) J"], polyether sulfone film [thickness: 50 g]
m, hereinafter referred to as "Film (2)"], plain woven glass cloth (fabric weight 400 g/rn', hereinafter referred to as "Glass cloth"), and non-woven fabric made of 1.5 denier aramid Ti&fiber by dry method ( A fabric with a basis weight of 250 g/m'' (hereinafter referred to as "nonwoven fabric") was used.

[(C) Inorganic filler]

Furthermore, low soda alumina (A1) is used as an inorganic filler.
203) content 88.9% by weight, true density 3.81
g/m”, average particle size 2gra, hereinafter rA120
3J) was used.

Examples 1-15. Comparative Examples 1 to 3 The above mixtures (I) to (I[[) and EAA and GM used in producing these mixtures
A (1) was transferred to an extruder (140 m) each equipped with a T-die.
The thickness was 50cm, 100#Lm under the conditions shown in Table 1, using a die width of 30cm and a rotational speed of 85 rpm.
A film of 200 JLl was formed and wound around a water-cooled roll at 20°C. Table 1 shows the properties of each film thus obtained.

(Left below) The resulting uncrosslinked film was sold to Energy 5sciences Inc.
Electron beam irradiation was carried out under a nitrogen atmosphere at an accelerating voltage of 175 KV and an irradiation dose of 10 Mrad using an electrocurtain type electron beam accelerator manufactured by Incorporated. The gel fraction of this irradiated film is 6
It was 0%.

Each film thus obtained was processed using a heat press machine at a temperature of 280°C for 10 minutes to produce 50Kg/c of each film.
Conductive metal layers, 81 fat layers and other materials listed in Table 2 in m' (gauge pressure) (i.e.

A printed wiring board was manufactured by laminating the base substrate).

The structure of each laminate is shown in the columns of Examples and Comparative Examples with the corresponding drawing numbers attached.

The results of the heat resistance test of each printed wiring board obtained in this way and the extraction residual of the crosslinked product of the resin layer mixture were evaluated in a second test.
The heat resistance test shown in the table is based on solder heat resistance and room temperature (2
Peeling tests of the conductive metal layer were carried out at temperatures of 3°C) and 100°C. In this peel test, the conductive metal layer was etched to a width of 10%, and the 180 degree peel strength was measured at a tensile rate of 50 mm/min.

Note that the copper foil used as the conductive metal layer is electrolytic copper foil (thickness 3
5gm) was used. In addition, "plated copper" refers to a laminate obtained by laminating a resin layer and a molded product of other materials.
Plating was carried out at 72° C. using a chemical plating solution containing the following compounds in an aqueous solution of 100 ml, to obtain a copper plating film of about 30 microns on both sides of the sheet.

Cu5Oa/5H2010g EDTA e2Na l2H2030gHCHO(3
8%) 3mM NaOH 12g After plating, the above masking was washed off, washed with water, and dried (see Table 2, "Conductive Metal Layer").

(Write “plated” in the column.)

In Example 2, 100 parts by weight of mixture (1) was mixed with 300 parts by weight of Al2O3.

(Left below) The film obtained by removing the entire copper foil by etching from the laminates obtained in Examples 7 and 12 was JIS K
Volume resistivity, dielectric constant (IMIl) according to -8911
t), dielectric loss tangent and withstand voltage were measured.

The volume resistivity was lOΩ·a, and the dielectric constant was 2.5↑. In addition, the dielectric loss tangent is 0.02, and the withstand voltage is 20
KV/ms Te Atsuta.

As is clear from Table 2, the crosslinked product of the mixture of the present invention has good adhesion to metal plates such as aluminum and silica steel plates, and molded products of other materials such as foils, thermosetting resins, and heat-resistant resin films. Excellent sex.

Moreover, it can be seen that the heat resistance is excellent. However, Example 5
and 6, because the heat resistance of the thermosetting resin substrate is poor,
The solder test was conducted at 280°C.

As is clear by comparing Comparative Examples 4 and 5 with the actual example, by adding epoxy resin, 1
It can be seen that the adhesive strength at 00°C is improved. This effect is effective for work such as mounting components and wire bonding at high temperatures after circuit formation.

From the results of the above examples and comparative examples, it is clear that when the crosslinked resin mixture of the present invention is used in the insulating layer and adhesive layer of printed wiring boards, it not only has excellent heat resistance but also has excellent adhesive strength with conductive circuit parts. Because of its large size, it is possible to increase density, attach various chip parts, and wire bonding.
It is clear that it can be used extensively in the future as a substrate for things such as Surf Ace ψ mounts.

The printed wiring board obtained by the present invention not only has good heat resistance as described above, but also has significantly improved reliability of electrical insulation, and has excellent crosslinking ability and adhesive properties when pressurized at high temperatures. It was invented based on an idea completely different from that of conventional heat-resistant polymer chemistry.

(1) Since no thermosetting resin adhesive such as epoxy resin is used, not only the adhesion process is omitted, but also the complicated drying process associated with that process is eliminated.

(2) Excellent electrical properties (for example, insulation, withstand voltage, and dielectric loss tangent performance).

(3) It has good heat resistance, and can not only withstand temperatures of 250°C or higher, but can also be applied to metals such as copper foil without using the adhesive by applying pressure at temperatures of 100°C or higher. It can be bonded well with layers.

(4) In particular, one feature of the printed wiring board obtained by the present invention is that, compared to the conventionally used adhesives made of heat-effect resin, the printed wiring board has a large size because it is crosslinked at a relatively high temperature (200°C or higher) as described below. It not only has excellent stability, but also has good adhesion even at high temperatures, has good adhesion, and has extremely few residual voids.

[Brief explanation of the drawing]

Figure 1-a, Figure 1-b, Figure 2-a, Figure 3-a, Figure 3-b, Figure 3-c, and Figure 3-d have a conductive metal layer laminated on one side. 1 is a partially enlarged cross-sectional view of a typical example of a printed wiring board having a structure in which one side is molded of another material; FIG. Moreover, FIG. 1-c and FIG. 2-b are partial enlarged sectional views of representative examples of a double-sided printed wiring board having a structure in which conductive metal layers are laminated on both sides. FIG. 2-c is a partially enlarged sectional view of a wiring board having a multilayer laminated structure, which is a combination of FIGS. 1-a to 1-c and FIGS. 2-a and 2-b. l... Metal layer 2... Thin wall material 3 crosslinked with mixture...
Other materials such as metal plates, ceramics, thermosetting resin substrates 4 Other materials such as thin metal foils and heat-resistant resins 5 Inorganic fillers 6 ...Heat-resistant m#I formed nonwoven fabric 7...
...Heat-resistant am-formed material in the form of a woven fabric 8...
・Through hole

Claims (1)

[Claims] It consists of at least a conductive metal and an insulating substrate, and the insulating substrate includes (A) at least units derived from ethylene and α, β-
unsaturated monocarboxylic acids, α,β-unsaturated dicarboxylic acids,
Copolymer (I) consisting of a unit derived from at least one monomer selected from the group consisting of its anhydride and half ester; and (B) ethylenically unsaturated containing at least a unit derived from ethylene and an epoxy group. It is a crosslinked product obtained by irradiating a thin mixture of copolymer (II) with units derived from monomers by electron beam irradiation, and the mixing ratio of copolymer (I) in the mixture is 10 to 80. % by weight, and the molar ratio of the sum of carboxyl groups and carboxylic acid anhydride groups to the sum of epoxy groups in the mixture is 0.2/1 to 5/1.
A printed wiring board characterized by: