JP2003082291A - Varnish and its application - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a varnish capable of forming such an electrical insulating layer that exhibits good flame retardancy, has excellent insulating properties, and is small in a change of dielectric constant, to provide an electrical insulating film obtained by using the varnish, and to provide a laminated material having the film. SOLUTION: This varnish comprises a curable vanish containing an electrical insulating polymer, a curing agent, a flame retardant, and an organic solvent, and satisfies requirements (1) and (2): (1) the flame retardant is obtained by treating surfaces of a flame retarder with a coupling agent; and (2) particles existing in the varnish have a secondary particle diameter of <=30 μm. The varnish is applied to a substrate, dried, cured, and formed into the electrical insulating film, so that a multilayer printed circuit board is obtained. When the varnish is given by preparing a flame retardant slurry composed of the flame retardant obtained by contacting the flame retarder with the coupling agent and an organic solvent, contacting the prepared slurry with a porous material, and mixing the resulted slurry with the electrical insulating polymer together with the curing agent, an increase in viscosity of the vanish is prevented, so that the electrical insulating film having excellent flatness is given even after the varnish is stored for a long period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a varnish used for producing an electric insulating film, and more specifically, it can form an electric insulating layer exhibiting good flame retardancy, excellent electric insulating property, and small change in dielectric constant. TECHNICAL FIELD The present invention relates to a varnish, an electric insulating film obtained by using the varnish, and a laminate having the electric insulating film.

[0002]

2. Description of the Related Art As electronic equipment becomes smaller and more multifunctional,
Circuit boards used in electronic devices are also required to have higher density. In order to increase the density of the circuit board, it is common to make the circuit board into multiple layers. A multilayer circuit board is usually obtained by stacking an electric insulating layer (2) on an inner layer substrate composed of an electric insulating layer (1) and a conductor circuit (1) formed on the surface of the electric insulating layer (2). It can be obtained by forming a conductor circuit (2) on 2) and further stacking an electric insulating layer and a conductor circuit in several stages, if necessary.

When wiring is formed in a multi-layered high density, the substrate itself and the electronic device itself generate heat. In order to prevent ignition due to this heat generation, a flame retardant is usually added to the electric insulating layer.

[0004]

As a result of studies by the present inventors, it was found that when a certain flame retardant is used, the electrical characteristics (dielectric constant) may change due to moisture absorption.
Therefore, the object of the present invention is to show good flame retardancy, and
An object of the present invention is to provide an electric insulating film having stable electric characteristics and a laminate having the electric insulating film. The present inventor has conducted extensive studies in order to achieve the above object, and as a result, by using a flame retardant obtained by bringing a flame retardant-imparting agent and a coupling agent into contact with each other, electrical insulation with little change in dielectric constant is obtained. It was found that a layer was obtained, and the present invention was completed based on this finding.

[0005]

Thus, according to the present invention, as a first invention, a curable varnish containing an insulating polymer, a curing agent, a flame retardant and an organic solvent,
(1) A flame retardant is obtained by surface-treating a flame retardant-imparting agent with a coupling agent, and (2) a varnish in which the secondary particle diameter of the particles present in the varnish is 30 μm or less is provided. As a second invention, a molded product obtained by drying the varnish is provided, as a third invention, an electrical insulating film obtained by curing the molded product is provided, and as a fourth invention, conductive Provided is a laminated body in which an electric insulating layer comprising an electric insulating film according to the third invention is formed on a substrate having a body circuit layer, and a flame retarding agent and a coupling agent are brought into contact with each other as a fifth invention. A flame retardant obtained by the above, and a flame retardant slurry comprising an organic solvent is provided, and the sixth invention is characterized by mixing the slurry, an insulating polymer, and a curing agent. A method for preparing a varnish according to the invention is provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The varnish of the present invention contains an insulating polymer, a curing agent, a flame retardant and an organic solvent. The varnish of the present invention is characterized in that secondary aggregated particles are small. That is, the secondary particle diameter of the particles present in the varnish is 30 μm or less, preferably 25 μm or less,
It is more preferably 20 μm or less. The secondary particle size is J
It is a value measured by the crushing test A method defined by ISK 5400. In the present invention, the secondary particle size is a value measured by this method unless otherwise specified.

As the insulating polymer, epoxy resin, maleimide resin, (meth) acrylic resin, diallyl phthalate resin, triazine resin, alicyclic olefin polymer,
Examples thereof include aromatic polyether polymers, benzocyclobutene polymers, cyanate ester polymers, liquid crystal polymers and polyimides. Among these, alicyclic olefin polymers, aromatic polyether polymers, benzocyclobutene polymers, cyanate ester polymers or polyimides are preferable, and alicyclic olefin polymers or aromatic polyether polymers are particularly preferable, Alicyclic olefin polymers are especially preferred. In addition to these polymers, liquid crystal polymers can also be used as preferred insulating polymers. As the liquid crystal polymer, a polymer of an aromatic or aliphatic dihydroxy compound, a polymer of an aromatic or aliphatic dicarboxylic acid, a polymer of an aromatic hydroxycarboxylic acid, an aromatic diamine, an aromatic hydroxyamine or an aromatic aminocarboxylic acid. A preferable example is a thermoplastic liquid crystal polymer such as a polymer of

The alicyclic olefin polymer is a polymer of unsaturated hydrocarbon having an alicyclic structure. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and the cycloalkane structure is preferable from the viewpoint of mechanical strength, heat resistance and the like. Further, the alicyclic structure may be either a monocyclic ring or a polycyclic ring (condensed polycyclic ring, bridged ring, polycyclic ring in combination thereof, etc.). The number of carbon atoms constituting the alicyclic structure is not particularly limited, but usually 4 to 3
0, preferably 5 to 20, more preferably 5 to 15
When it is in the range of individual pieces, various properties such as mechanical strength, heat resistance, and moldability are highly balanced, which is preferable. Further, the alicyclic olefin polymer used in the present invention is usually thermoplastic.

The alicyclic olefin polymer preferably has a polar group. As the polar group, a hydroxyl group,
Carboxyl group, alkoxyl group, epoxy group, glycidyl group, oxycarbonyl group, carbonyl group, amino group, ester group, carboxylic acid anhydride group and the like,
Particularly, a carboxyl group or a carboxylic acid anhydride group is preferable.

The alicyclic olefin polymer is usually obtained by addition-polymerizing or ring-opening polymerizing an alicyclic olefin, and optionally hydrogenating an unsaturated bond portion, or adding an aromatic olefin to a polymer. It is obtained by ring-opening polymerization and hydrogenating the aromatic ring portion of the polymer. Further, the alicyclic olefin polymer having a polar group,
For example, 1) introducing a polar group into the alicyclic olefin polymer by a modification reaction, 2) copolymerizing a monomer containing a polar group as a copolymerization component, or 3) an ester group, etc. It can be obtained by copolymerizing a monomer containing a polar group of 1 as a copolymerization component, and then removing an ester group or the like by hydrolysis or the like.

Examples of the alicyclic olefin used for obtaining the alicyclic olefin polymer include bicyclo [2.2.
1] -hept-2-ene (conventional name: norbornene), 5
-Methyl-bicyclo [2.2.1] -hept-2-ene, 5,5-dimethyl-bicyclo [2.2.1] -hept-2-ene, 5-ethyl-bicyclo [2.2.1] ]-
Hept-2-ene, 5-butyl-bicyclo [2.2.
1] -Hept-2-ene, 5-hexyl-bicyclo [2.2.1] -hept-2-ene, 5-octyl-bicyclo [2.2.1] -hept-2-ene, 5-octadecyl -Bicyclo [2.2.1] -hept-2-ene,
5-ethylidene-bicyclo [2.2.1] -hept-2
-Ene, 5-methylidene-bicyclo [2.2.1] -hept-2-ene, 5-vinyl-bicyclo [2.2.1]
-Hept-2-ene,

5-Propenyl-bicyclo [2.2.1]
-Hept-2-ene, 5-methoxy-carbonyl-bicyclo [2.2.1] -hept-2-ene, 5-cyano-
Bicyclo [2.2.1] -hept-2-ene, 5-methyl-5-methoxycarbonyl-bicyclo [2.2.1]
-Hept-2-ene, 5-ethoxycarbonyl-bicyclo [2.2.1] -hept-2-ene, bicyclo [2.
2.1] -hept-5-enyl-2-methylpropionate, bicyclo [2.2.1] -hept-5-enyl-
2-methyl octanate,

Bicyclo [2.2.1] -hept-2-ene-5,6-dicarboxylic acid anhydride, 5-hydroxymethylbicyclo [2.2.1] -hept-2-ene, 5,6
-Di (hydroxymethyl) -bicyclo [2.2.1]-
Hept-2-ene, 5-hydroxy-i-propylbicyclo [2.2.1] -hept-2-ene, 5,6-dicarboxy-bicyclo [2.2.1] -hept-2-ene, Bicyclo [2.2.1] -hept-2-ene-5,
6-dicarboxylic acid imide, 5-cyclopentyl-bicyclo [2.2.1] -hept-2-ene, 5-cyclohexyl-bicyclo [2.2.1] -hept-2-ene, 5
-Cyclohexenyl-bicyclo [2.2.1] -hept-2-ene, 5-phenyl-bicyclo [2.2.1]-
Hept-2-ene,

Tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (conventional name: dicyclopentadiene),
Tricyclo [4.3.0.1 ^2,5 ] deca-3-ene,
Tricyclo [4.4.0.1 ^2,5 ] undeca-3,7
- diene, tricyclo [4.4.0.1 ^{2, 5]} undec-3,8-diene, tricyclo [4.4.0.1 ^{2
, 5} ] Undeca-3-ene, tetracyclo [7.4.
0.1 ^{10, 13} . 0 ^{2, 7} ] -Trideca-2,4,6
-11-Tetraene (alias: 1,4-methano-1,4,4)
4a, 9a-tetrahydrofluorene), tetracyclo [8.4.0.1 ^{1 1,14} . 0 ^3,8 ] -tetradeca-3,5,7,12-11-tetraene (alias: 1,4
-Methano-1,4,4a, 5,10,10a-hexahydroanthracene),

Tetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] -Dodeca-3-ene (trivial name: tetracyclododecene), 8-methyl-tetracyclo [4.4.0.
1 ^{2 , 5} . 1 ^7,10 ] -dodec-3-ene, 8-ethyl-tetracyclo [4.4.0.1 ^2,5 .
1 ^7,10 ] -dodec-3-ene, 8-methylidene-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -Dodeca-3-ene, 8-ethylidene-tetracyclo [4.
4.0.1 ^2,5 . 1 ^7,10 ] -dodeca-3-ene,
8-Vinyl-tetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] -dodeca-3-ene, 8-propenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] - dodeca-3-ene, 8-methoxycarbonyloxy - tetracyclo [4.4.0.1 ^2, 5. 1 ^7,10 ] -dodeca-3-
Ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} ] -Dodeca-
3-ene, 8-hydroxymethyl-tetracyclo [4.
4.0.1 ^2,5 . 1 ^7,10 ] -dodeca-3-ene,
8-carboxy-tetracyclo [4.4.0.
1 ^2,5 . 1 ^{7, 10]} - dodeca-3-ene,

8-cyclopentyl-tetracyclo [4.
4.0.1 ^2,5 . 1 ^7,10 ] -dodeca-3-ene,
8-cyclohexyl-tetracyclo [4.4.0.1
^2,5 . 1 ^7,10 ] -dodec-3-ene, 8-cyclohexenyl-tetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] -dodeca-3-ene, 8-phenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -Dodeca-3-ene, pentacyclo [6.5.1.1 ^3,6 . 0
^2,7 . 0 ^9,13] pentadeca-3,10-diene,
Pentacyclo [7.4.0.1 ^3,6 . 1 ^{10, 13} .
Norbornene-based monomers such as 0 ^2,7 ] -pentadeca-4,11-diene;

Cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7- Monocyclic cycloalkenes such as methano-1H-indene and cycloheptene; vinyl-based alicyclic hydrocarbon-based monomers such as vinylcyclohexene and vinylcyclohexane; alicyclic-conjugated diene-based monomers such as cyclopentadiene and cyclohexadiene; Is mentioned.

Aromatic olefins include styrene and α
-Methylstyrene, divinylbenzene and the like.

The alicyclic olefin and / or aromatic olefin may be used alone or in combination of two or more kinds.

The alicyclic olefin polymer may be obtained by copolymerizing the alicyclic olefin and / or aromatic olefin with a copolymerizable monomer thereof. Monomers copolymerizable with alicyclic olefins or aromatic olefins include ethylene; propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene. , 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-
Hexene, 4,4-dimethyl-1-hexene, 4,4-
Dimethyl-1-pentene, 4-ethyl-1-hexene,
Carbon number 3 such as 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene
~ 20 α-olefins; 1,4-hexadiene, 4-
Methyl-1,4-hexadiene, 5-methyl-1,4-
Non-conjugated dienes such as hexadiene and 1,7-octadiene; and the like. These monomers may be used alone or in combination of two or more.

The method for polymerizing alicyclic olefins and aromatic olefins, and the method for hydrogenation, which is carried out if necessary, are as follows:
There is no particular limitation, and it can be performed according to a known method.

Specific examples of the alicyclic olefin polymer include ring-opening polymers of norbornene-based monomers and hydrogenated products thereof, addition polymers of norbornene-based monomers, norbornene-based monomers and vinyl compounds. Addition polymers, monocyclic cycloalkene polymers, alicyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers and hydrogenated products thereof, and aromatic ring hydrogenated products of aromatic olefin polymers. . Of these, ring-opening polymers of norbornene-based monomers and hydrogenated products thereof, addition polymers of norbornene-based monomers, addition polymers of norbornene-based monomers and vinyl compounds, aromatic olefin polymers Aromatic ring hydrogenated products are preferred,
A hydrogenated product of a ring-opening polymer of a norbornene-based monomer is particularly preferable. The above alicyclic olefin polymers may be used alone or in combination of two or more. Among alicyclic olefin polymers, ring-opening polymers of norbornene-based monomers and hydrogenated products thereof are obtained by copolymerizing olefins represented by C _n H _2n due to the difference in their structures. The obtained polyolefin resin is classified into different polymers.

The alicyclic olefin polymer is not particularly limited by its molecular weight. The molecular weight of the alicyclic olefin polymer is the polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) using cyclohexane or toluene as an organic solvent.
, Usually 1,000 to 1,000,000, preferably 5,000 to 500,000, and more preferably 10.0.
It is in the range of 00 to 250,000. When the weight average molecular weight (Mw) of the alicyclic olefin polymer is in this range, heat resistance and smoothness of the surface of the molded product are balanced, which is preferable.

The molecular weight distribution of the alicyclic olefin polymer is
Weight average molecular weight (Mw) and number average molecular weight (M) measured by GPC using cyclohexane or toluene as an organic solvent.
The ratio (Mw / Mn) with respect to n) is usually 5 or less, preferably 4 or less, more preferably 3 or less. The ranges and measuring methods of the weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) described above are suitable for the norbornene-based polymer, but are not limited thereto. Further, in the case of an alicyclic olefin polymer whose weight average molecular weight or molecular weight distribution cannot be measured by the above-mentioned method, one having a melt viscosity and a degree of polymerization sufficient to form a resin layer by a usual melt processing method is used. be able to.

The glass transition temperature of the alicyclic olefin polymer can be appropriately selected according to the purpose of use, but is usually 50 ° C. or higher, preferably 70 ° C. or higher, more preferably 100 ° C. or higher, most preferably 125 ° C. or higher. is there.

There is no particular limitation on the curing agent used in the present invention. For example, an ionic curing agent, a radical curing agent, or a curing agent having both ionic and radical properties is used, and insulation resistance and heat resistance are used. The ionic curing agent is preferable from the viewpoints of chemical resistance, chemical resistance, and compatibility with the alicyclic olefin polymer. Above all, a nitrogen-based curing agent containing a nitrogen atom is preferable, and a nitrogen-based curing agent containing no halogen element is more preferable.

Examples of the nitrogen-based curing agent include aliphatic polyamines such as hexamethylenediamine, triethylenetetramine, diethylenetriamine and tetraethylenepentamine; diaminocyclohexane, 3 (4), 8
(9) -bis (aminomethyl) tricyclo [5.2.
1.0 ^2,6 ] decane; 1,3- (diaminomethyl) cyclohexane, menthenediamine, isophoronediamine N-aminoethylpiperazine, bis (4-amino-3-)
Alicyclic polyamines such as methylcyclohexyl) methane and bis (4-aminocyclohexyl) methane; 4,4 ′
-Diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, α, α'-bis (4-aminophenyl) -1,3-diisopropylbenzene, α, α'-bis (4-aminophenyl) -1,4-diisopropyl Aromatic polyamines such as benzene, 4,4′-diaminodiphenyl sulfone, metaphenylenediamine, metaxylylenediamine; nylon-6, nylon-66,
Nylon-610, Nylon-11, Nylon-61
2, polyamide such as nylon-12, nylon-46, methoxymethylated polyamide, polyhexamethylenediamine terephthalamide, polyhexamethylene isophthalamide; isocyanate such as hexamethylene diisocyanate, toluylene diisocyanate; isocyanuric acid;

Triallyl cyanurate; 1-allyl isocyanurate, 1,3-diallyl isocyanurate, 1,
3-diallyl-5-benzyl isocyanurate, triallyl isocyanurate, 1-allyl-3,5-dibenzyl isocyanurate; 1-allyl-3,5-diglycidyl isocyanurate, 1,3-diallyl-5-glycidyl Isocyanurate, triglycidyl isocyanurate, 1,3-diallyl-5- (2-hydroxy-3-butoxypropyl) -1,3,5-triazine-2,4
6 (1H, 3H, 5H) -trione, 1,3-diallyl-5- (2-hydroxy-3-phenoxypropyl)-
1,3,5-triazine-2,4,6 (1H, 3H, 5
H) -trione and other compounds having an isocyanurate structure; glycidyl amine type epoxy compounds; Of these, a nitrogen-based curing agent containing an allyl group and an epoxy group is preferable, and particularly 1-allyl-3,5-diglycidyl isocyanurate and 1,3-diallyl-5-.
A halogen-free isocyanurate curing agent containing an allyl group and an epoxy group such as glycidyl isocyanurate is preferable.

These nitrogen-based curing agents can be used alone or in combination of two or more, and the mixing ratio thereof is usually 5 to 150 parts by weight with respect to 100 parts by weight of the insulating polymer, The range is preferably 15 to 110 parts by weight, more preferably 30 to 100 parts by weight.

Of course, other than these nitrogen-based curing agents, for example, bisazide compounds, acid anhydrides, dicarboxylic acid compounds, diol compounds, triol compounds, polyhydric phenol compounds, glycidyl ether type epoxy compounds, alicyclic epoxy compounds. A polyvalent epoxy compound having no nitrogen atom, such as a glycidyl ester type epoxy compound, or a commonly used curing agent may be used.

The curing agents can be used alone or in combination of two or more, and the compounding ratio thereof is usually 5 to 150 parts by weight with respect to 100 parts by weight of the insulating polymer,
Preferably 15 to 110 parts by weight, more preferably 30 to
It is in the range of 100 parts by weight.

A curing accelerator or a curing aid may be used to accelerate the curing reaction between the insulating polymer and the curing agent. The curing accelerator is not particularly limited. For example, the curing agent is preferably a tertiary amine compound or a boron trifluoride complex compound. Among them, the use of the tertiary amine compound improves the stacking property for fine wiring, insulation resistance, heat resistance, and chemical resistance.

Specific examples of the tertiary amine compound include:
Chain tertiary amine compounds such as benzyldimethylamine, triethanolamine, triethylamine, tributylamine, tribenzylamine, dimethylformamide; pyrazoles, pyridines, pyrazines, pyrimidines, indazoles, quinolines, isoquinolines,
Examples include compounds such as imidazoles and triazoles. Among these, imidazoles, especially substituted imidazole compounds having a substituent are preferable.

Specific examples of the substituted imidazole compound include 2-ethylimidazole, 2-ethyl-4-methylimidazole, bis-2-ethyl-4-methylimidazole, 1-methyl-2-ethylimidazole and 2-isopropylimidazole. , 2,4-Dimethylimidazole, 2-heptadecylimidazole and other alkyl-substituted imidazole compounds; 2-phenylimidazole, 2-
Phenyl-4-methylimidazole, 1-benzyl-2
-Methyl imidazole, 1-benzyl-2-ethyl imidazole, 1-benzyl-2-phenyl imidazole,
Benzimidazole, 2-ethyl-4-methyl-1-
(2'-Cyanoethyl) imidazole, 2-ethyl-4
Examples include aryl group such as -methyl-1- [2 '-(3 ", 5" -diaminotriazinyl) ethyl] imidazole and imidazole compound substituted with hydrocarbon group having ring structure such as aralkyl group. To be Among these, imidazole having a ring structure-containing substituent is preferable from the viewpoint of compatibility with the alicyclic olefin polymer, and 1-benzyl-2-phenylimidazole is particularly preferable.

The curing accelerator may be used alone or in combination of two or more kinds. The compounding amount of the curing accelerator is appropriately selected according to the purpose of use, but the insulating polymer 100
0.001 to 30 parts by weight, preferably 0.01 to 10 parts by weight, and more preferably 0.03 to 10 parts by weight.
5 parts by weight.

The curing aid is used if necessary. Examples of the curing aid include oxime / nitroso-based curing aids such as quinonedioxime, benzoquinonedioxime and p-nitrosophenol; maleimide-based curing aids such as N, Nm-phenylene bismaleimide; diallyl phthalate, Allyl type curing aids such as triallyl cyanurate and triallyl isocyanurate; methacrylate type curing aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; vinyl type curing aids such as vinyltoluene, ethylvinylbenzene and divinylbenzene. Agents and the like. In addition, a peroxide that functions as a curing aid for a curing agent having an allyl group can be used.

Examples of the peroxide include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide,
2,5-Dimethyl-2,5- (peroxide benzoate) -3-hexyne, 1,4-bis (tert-butylperoxyisopropyl) benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-2, 5-di (tert-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (tert
-Butylperoxy) hexane, tert-butyl perbenzoate, tert butyl perphenylacetate, tert-butyl perisobutyrate, tert-
Butyl per-sec-octoate, tert-butyl perpiperate, cumyl perpiperate and tert-
Butyl perdiethyl acetate, methyl ethyl ketone peroxide, cyclohexanone peroxide, 1,1-
Bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, 2,5
-Dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5
-Di (t-butylperoxy) hexyne-3, α, α '
Examples include -bis (t-butylperoxy-m-isopropyl) benzene, octanoyl peroxide, isobutyryl peroxide, and peroxydicarbonate. Among these peroxides, those containing no halogen element are preferable. The amount of peroxide is 100% insulating polymer.
It is usually 0.1 to 40 parts by weight, preferably 1 to 20 parts by weight, based on parts by weight. When the amount of the peroxide is within this range, the stacking property such as wiring embedding is more excellent.

The flame retardant used in the present invention is obtained by surface-treating a flame retardant-imparting agent with a coupling agent,
Usually, the surface treatment is performed by bringing the flame retardant-imparting agent and the coupling agent into contact with each other. The flame retardant may be a compound generally used as a flame retardant. Further, the flame retardancy-imparting agent is preferably in the form of particles. The average major axis of the primary particles of the flame retardancy-imparting agent is usually 0.01 to 5 μm, preferably 0.05 to 3 μm, and the average aspect ratio (= average major axis / average minor axis) is usually 5 or less, preferably 3 It is the following. Furthermore, when the number of particles having a major axis of 10 μm or less is 10% or less, preferably 5% or less, particularly preferably 1% or less, a multilayer circuit board having high flame retardancy and excellent electrical insulation is obtained. be able to. The flame retardant agent is
From the viewpoint of environmental protection, a halogen-free compound (hereinafter referred to as a non-halogen flame retardant) that does not generate a halogen-containing harmful substance when incinerated is preferable. Specific examples of non-halogen flame retardants include antimony trioxide, antimony pentoxide, and antimony compounds such as sodium antimonate; aluminum hydroxide, magnesium hydroxide, zinc borate, guanidine sulfamate, zirconium compound, molybdenum compound, tin compound. Other inorganic flame retardants such as
Triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, resorcinol bis ( Diphenyl) phosphate, 2-ethylhexyl diphenyl phosphate, dimethyl methyl phosphate, triallyl phosphate,
Diethylbis (hydroxyethyl) aminomethyl phosphate, triallyl phosphate, tris (3-hydroxypropyl) phosphine oxide, glycidyl-α-
Methyl-β-di (butoxy) phosphinyl propionate, dibutylhydroxymethylphosphonate, dimethylmethylphosphonate, aromatic condensed phosphoric acid ester, di (ethoxy-bis- (2-hydroxyethyl)-
Aminomethyl phosphate, di (polyoxyethylene)
-Hydroxymethyl phosphate, ammonium polyphosphate, butyl pyrophosphate, butyl acid phosphate, butoxyethyl acid phosphate, 2
-Ethylhexyl acid phosphate, diethylphenylphosphonate, dimethylphenylphosphonate, di (isopropyl) N, N-bis (2-hydroxyethyl) aminomethylphosphonate, dibutylbis (2-hydroxypropyl) pyrophosphonate, Phenylphosphinic acid,

Melamine polyphosphate salt, melamine melam / melem double salt polyphosphate, red phosphorus, guanidine phosphate, guanylurea phosphate, polyphosphoric acid sulfate, diphenylphosphoric acid ester-2-propenylamide, diphenylphosphorus Acid ester-2-hydroxyethylamide, diphenylphosphoric acid ester-di (2-hydroxyethyl) amide, diphenylphosphoric acid ester-di-2-cyanoethylamide, diphenylphosphoric acid ester-p-hydroxyphenylamide, diphenylphosphoric acid ester -M-hydroxyphenylamide, diphenylphosphoric acid ester-cyclohexylamide; phenylphosphoric acid ester-di-N, N-
Phenylmethylamide, phenyl phosphate-di-
N-cyclohexylamide, di (butoxy) phosphinylpropylamide, 1,3,5-triazine derivative salt of polyacid containing phosphorus, sulfur and oxygen (JP-A-10-30
No. 6082, etc.) and the like. Of these, phosphorus-containing compounds are preferable, and phosphorus-based flame retardants composed of a salt of a basic nitrogen-containing compound and phosphoric acid are particularly preferable.

The salt of a basic nitrogen-containing compound and phosphoric acid is usually a phosphoric acid source such as ammonium orthophosphate, orthophosphoric acid, condensed phosphoric acid, phosphoric anhydride, urea phosphate and a mixture thereof, and nitrogen. Heat-condensation of melamine, dicyancyanamide, guanidine, guanylurea, and mixtures thereof as a source in the presence of urea, urea phosphate (which also serves as a phosphoric acid source) as a condensing agent, and a mixture thereof. It is obtained by reacting and then firing.

The median diameter of the particles thus obtained is 1
Although it is 0 μm or less, its shape is needle-like or whisker-like. Many of these particles have 20% or more of particles having a major axis of more than 10 μm, and have an average major axis of 10%.
It becomes about 20 μm. In such a case, a salt of a needle-shaped or whisker-shaped basic nitrogen-containing compound and phosphoric acid, by wet pulverizing in a mixed organic solvent consisting of a polar organic solvent and a nonpolar organic solvent similar to the following, The aspect ratio can be adjusted as described above. If the weight ratio of the non-polar organic solvent is too large, the salt of the nitrogen-containing compound and phosphoric acid may aggregate during pulverization, making it difficult to obtain the desired particle shape. On the other hand, if the weight ratio of the non-polar organic solvent is too small, secondary agglomeration is likely to occur and the dispersion in the insulating polymer may be deteriorated.

By bringing the coupling agent into contact with the flame-retardant imparting agent, the coupling agent is physically or chemically bonded (including adsorption) to the surface of the flame-retardant imparting agent to impart flame retardancy. It improves the dispersion by reducing the aggregation of the agent, and includes silane compounds, metal ester compounds, metal complex compounds and metal chelate compounds. Among them, a metal chelate compound is preferable because it is stable in an organic solvent. The metal chelate compound may be one in which a metal and an organic compound residue form a chelate, and preferably in a metal alkoxide such as aluminum, titanium, tin or zinc.
A part of the alkoxy groups is replaced with an organic compound residue such as an ester residue, a carboxylic acid residue, or another alkoxy group (alcohol residue). Aluminum chelate compounds and titanium chelate compounds, which are metal chelate compounds containing aluminum and titanium, are particularly preferable because they are stable in the dispersion solution. The structures of these metal chelate compounds are not particularly limited and may be either monomer type or polymer type. As a specific aluminum chelate compound, for example, diisopropoxyaluminum monooleyl acetoacetate, monoisopropoxy aluminum pisoleyl acetoacetate, monoisopropoxy aluminum monomethacrylate monooleyl acetoacetate, monoisopropoxy aluminum monooleate monoethyl acetoacetate. , Monoisopropoxy aluminum monoethyl acetoacetate monooleyl acetoacetate, diisopropoxy aluminum monolauryl acetoacetate, diisopropoxy aluminum monostearyl acetoacetate, diisopropoxy aluminum monoisostearyl acetoacetate, monoisopropoxy aluminum bisoleyl acetoacetate , Monoisopropoxyl Aluminum monomethacrylate Monooleyl acetoacetate, Monoisopropoxy aluminum monooleate monoethyl acetoacetate, Monoisopropoxy aluminum monooleyl alkoxide monoethyl acetoacetate, Monoisopropoxy aluminum monologinate monolauryl acetoacetate, Diisopropoxy aluminum Monoabietyl acetoacetate, and monoisopropoxy aluminum mono-N-lauroyl-β
And fatty acid-based aluminum chelate compounds such as alanate monolauryl acetoacetate. Metal chelate compound containing titanium (titanium chelate compound)
As isopropyl trioctanoyl titanate,
Isopropyldimethacrylisostearoyl titanate, isopropyltrisstearoyl titanate, isopropyltrisisostearoyl titanate, isopropyldiacrylic titanate, dicumylphenyloxyacetate titanate, diisostearoylethylene titanate and fatty acid titanium chelate compounds, isopropyltri (dioctylphosphate) Titanate,
Isopropyl tris (dioctyl biphosphate)
Titanate, tetraisopropylbis (dioctylphosphite) titanate, tetraoctylbis (didodecylphosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (dioctylbiphosphate) oxyacetate titanate, bis ( Dioctyl biphosphate) ethylene titanate and phosphate-based titanium chelate compounds, isopropyl tridecylbenzene sulfonyl titanate,
Isopropyl bis (N-amidoethyl / aminoethyl)
Titanate as well as other titanium chelate compounds.

The method of surface-treating the flame retardancy-imparting agent with a coupling agent is not particularly limited. For example, adding a coupling agent while dispersing the flame retardant in an organic solvent,
Method of contacting these, adding a coupling agent after dispersing the flame retardant in an organic solvent, a method of contacting them, or disperse the flame retardant in an organic solvent containing a coupling agent in advance And a method of bringing them into contact with each other. The ratio of the coupling agent used is
It is 0.1 to 40 parts by weight, preferably 0.5 to 30 parts by weight, based on 100 parts by weight of the flame retardancy-imparting agent. The contact (surface treatment) between the coupling agent and the flame retardancy-imparting agent may be carried out while pulverizing the flame-retardancy-imparting agent by a wet method, but stirring is carried out for the purpose of reducing the aggregation of the flame-retardancy imparting agent. It is preferable to carry out. The treatment temperature is not particularly limited, but it is preferably performed at a temperature not higher than the boiling point of the organic solvent from the viewpoint of workability and safety. The treatment is usually performed until the aggregation of the flame retardancy-imparting agent is reduced, and it is preferable to continue the treatment until the secondary particle diameter becomes 20 μm or less. These surface treatments are preferably performed with a mixed organic solvent composed of a polar organic solvent and a nonpolar organic solvent.

The polar organic solvent is an organic solvent having a polar group such as a halogen group, a carbonyl group, a carboxyl group, a hydroxyl group, an ester group, an amino group and an amide group. Examples thereof include halogenated hydrocarbon organic solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; ketone organic solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone. Of these, ketone organic solvents are preferable.

The non-polar organic solvent is a hydrocarbon compound having no polar group. Examples thereof include aromatic hydrocarbons such as toluene, xylene, ethylbenzene and trimethylbenzene; aliphatic hydrocarbons such as n-pentane, n-hexane and n-heptane; alicyclic hydrocarbons such as cyclopentane and cyclohexane. . Of these, aromatic hydrocarbons are preferred. The mixing ratio of the non-polar organic solvent and the polar organic solvent can be appropriately selected, but the weight ratio is usually 5:95 to 95: 5, preferably 10:90 to.
90:10, more preferably 20:80 to 80:20.

The slurry of the flame retardant thus obtained is characterized in that secondary aggregated particles are small. If necessary, the organic solvent can be removed from the flame retardant slurry and dried. The method is not particularly limited, and examples thereof include a method of previously separating the slurry into a flame retardant-imparting agent and an organic solvent with a filter cloth and then drying. The drying temperature is not particularly limited as long as it is a temperature at which the flame retardant-providing agent does not decompose and the organic solvent volatilizes. The drying device is not particularly limited as long as it is a device that prevents the organic solvent from catching fire and the flame retardant agent from causing a dust explosion, and a one-pass oven, an inert oven or the like is used. The amount of the flame retardant is appropriately selected according to the purpose of use, but is usually 0.1 with respect to 100 parts by weight of the insulating polymer.
-50 parts by weight, preferably 1-20 parts by weight.

For the purpose of enhancing the storage stability of the obtained curable composition, it is preferable to bring the porous material into contact with the slurry. Examples of the porous material include silica gel, diatomaceous earth, activated alumina, magnesia, titania, silica-
Alumina, zeolite, molecular sieve, porous silicon, porous glass beads, activated clay, mica, inorganic porous materials such as kaolin, magnetite, ferrite, nickel oxide, etc., organic carbon such as activated carbon, molecular sieving carbon, ion exchange resin, etc. Porous materials,
Among the inorganic porous materials, silica gel is preferred from the viewpoint of ease of separation from the slurry. The silica gel preferably has a pore size of 3 to 500 nm, more preferably 5 to 100 nm, and most preferably 7 to 50 nm. One type of porous material, or two
It is also possible to mix and use more than one kind. The method of contacting the porous material and the slurry is not particularly limited,
For example, 1) a method of adding a porous substance to the slurry, stirring and mixing, and 2) a method of passing the slurry through a filter made of a porous substance. More specifically, for example, in the case of the method 1), the slurry containing the porous substance may be left standing or stirred. The stirring method is not particularly limited, and for example, stirring using a glass rod, stirring using a stirrer and a magnetic stirrer, a stirrer, a penetrator, etc. can be used. The shape of the stirrer and the shape of the blade used in the stirrer are not particularly limited. The treatment temperature is preferably 5 ° C. to 70 ° C., more preferably 15 ° C. to 50 ° C. If the temperature is out of this range, the performance of the slurry will deteriorate. Further, the treatment time is preferably 5 hours or longer, and when the treatment time is 5 hours or shorter, the effect of the present invention is not sufficiently exhibited. After contacting in such a manner, the porous material is separated. The method for separating the porous substance and the slurry may be according to a conventional method, for example, filtration using a filter paper, filter cloth, glass fiber, quartz, glass filter, filter dish, silica fiber, etc. as a filter layer, decantation. Etc. The method of filtration is not particularly limited, and pressure treatment, suction treatment or the like may be performed to increase the filtration efficiency. The amount of the porous material added was 100 parts by weight of the flame retardant in the slurry.
It is 1 to 50 parts by weight, preferably 0.5 to 40 parts by weight.

In order to obtain a varnish or an electric insulating film having a small amount of secondary agglomerated particles, it is preferable to use the above-mentioned slurry of the flame retardant of the present invention as the flame retardant. The flame retardant slurry of the present invention comprises the surface-treated flame retardant described above and an organic solvent. The slurry may be a) a slurry of the flame retardant after the surface treatment obtained by the above method and before the removal of the organic solvent, or b) a slurry obtained by further adding an organic solvent to the slurry of a), or c ) Even in a slurry in which the organic solvent is partially removed from the slurry in a), d) after the surface treatment, the organic solvent is removed, and the dried flame retardant and the organic solvent are mixed to prepare a newly prepared flame retardant. It may be a slurry. The organic solvent that makes up the slurry is
The same polar organic solvent and non-polar organic solvent as described above can be used. The method of mixing the slurry is not particularly limited, and examples thereof include a method using a stirrer having a stirring blade, a wet disperser, and the like. In the slurry of the present invention, the concentration of the flame retardant in the organic solvent is not particularly limited, but is usually 5 to 80% by weight, preferably 10 to 60% by weight from the viewpoint of operability during varnish preparation. The slurry of the present invention has a secondary particle diameter of particles present in the slurry of 30 μm or less, preferably 25 μm or less, more preferably 20 μm or less. By using such a slurry, a varnish containing few secondary aggregated particles can be easily obtained. The solid content concentration of the slurry of the flame retardant is 5% by weight or more and 90% by weight or less, and the viscosity is 100 Pa · s or less from the viewpoint of workability within a range in which the desired composition can be blended.

Other components may be added to the varnish of the present invention as desired. For example, it is preferable to mix a compound having absorption in the wavelength region of the laser beam used when forming holes such as via holes and through holes. For example, when a carbon dioxide laser is used, silica or the like is used, and when an ultraviolet laser (for example, UV-YAG laser or the like) is used, an ultraviolet absorber is used. When a composition containing a compound having an absorption in the wavelength region of the laser beam is used, it is easy to form holes with a laser and smear is reduced. Specific examples of the ultraviolet absorber include salicylic acid compounds such as phenyl salicylate, p-tert-butylphenyl salicylate and p-octylphenyl salicylate; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy. -4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4- Methoxy-5
Benzophenone compounds such as sulfobenzophenone and bis (2-hydroxy-4-methoxybenzoylphenyl) methane;

2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-ter
t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-ter
t-amylphenyl) benzotriazole, 2- [2 ′
-Hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2-methylenebis [4-
(1,1,3,3-tetramethylbutyl) -6- (2H
-Benzotriazol-2-yl) phenol], 2-
A benzotriazole-based compound such as [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] benzotriazole; 2,4-di-tert-butylphenyl-3 ′, 5′-di-tert- Benzoate-based compounds such as butyl-4'-hydroxybenzoate; 2
-Cyanoacrylate compounds such as ethylhexyl-2-cyano-3,3'-diphenylacrylate and ethyl-2-cyano-3,3'-diphenylacrylate;
Bis (2,2,6,6-tetramethylpiperidinyl 4)
Hindered amine compounds such as sebacate; nickel bis (octylphenyl) sulfide, [2,2'-
Thiobis (4-tert-octylphenolate)]-
Examples thereof include organic metal compounds such as n-butylamine nickel, and inorganic compounds such as zinc oxide, tin oxide, titanium oxide, calcium carbonate, silica and clay. Among these, benzotriazole compounds are preferable from the viewpoint of compatibility with the ring structure-containing polymer and excellent stability during heat curing. The amount of the ultraviolet absorbent is usually 0.1 to 30 parts by weight, preferably 1 to 100 parts by weight of the insulating polymer.
10 parts by weight.

In addition, a soft polymer (particularly preferably an epoxy resin which is liquid at room temperature such as hydrogenated bisphenol A type liquid epoxy compound), a heat stabilizer, a weather stabilizer, an antiaging agent, a leveling agent, an antistatic agent, Slip agents, antiblocking agents, antifogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, emulsions, fillers and the like can be used as other components. The blending ratio is appropriately selected within a range that does not impair the object of the present invention.

The above-mentioned insulating polymer, curing agent, flame retardant (including slurry of flame retardant), other components optionally blended, and organic solvent are mixed to obtain the varnish of the present invention. . There are no particular restrictions on how to obtain varnish. The temperature at the time of mixing these is within the range where the reaction with the curing agent does not affect workability, and from the viewpoint of safety, it is preferably not higher than the boiling point of the organic solvent used at the time of mixing. Examples of the organic solvent include aromatic hydrocarbon organic solvents such as toluene, xylene, ethylbenzene and trimethylbenzene; aliphatic hydrocarbon organic solvents such as n-pentane, n-hexane and n-heptane; cyclopentane and cyclohexane. Alicyclic hydrocarbon organic solvents such as; halogenated hydrocarbon organic solvents such as chlorobenzene, dichlorobenzene, trichlorobenzene; ketone organic solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, etc. it can. These organic solvents can be used alone or in combination of two or more kinds.

Among these organic solvents, the ones that are excellent in embedding in fine wiring and do not generate bubbles etc.
A mixed organic solvent in which a nonpolar organic solvent such as an aromatic hydrocarbon organic solvent or an alicyclic hydrocarbon organic solvent and a polar organic solvent such as a ketone organic solvent are mixed is preferable. The mixing ratio of the non-polar organic solvent and the polar organic solvent can be appropriately selected, but the weight ratio is usually 5:95 to 95: 5, preferably 10:90 to 90:10, and more preferably 20 :.
The range is 80 to 80:20.

The amount of the organic solvent used is appropriately selected depending on the purpose of controlling the thickness and improving the flatness, but the solid content concentration of the varnish is usually 5 to 70% by weight, preferably 10 to 6%.
It is in the range of 5% by weight, more preferably 20 to 60% by weight.

The mixing method of each component may be a conventional method,
For example, stirring can be performed using a stirrer and a magnetic stirrer, a method using a high speed homogenizer, a dispersion, a planetary stirrer, a twin-screw stirrer, a ball mill, a triple roll, or the like.

The varnish of the present invention is dried to obtain the molded product of the present invention. The molded product is usually coated on an arbitrary support and dried to form a sheet or film. Examples of the support for obtaining such a molded product include a resin film (carrier film) and a metal foil. When a sheet or film is obtained as the molded product of the present invention, the molding method is not particularly limited, but in the present invention, it is preferably molded by the solution casting method or the melt casting method. In the solution casting method, the organic solvent is dried and removed after the varnish is applied to the support. Resin film (carrier film) as a support used in the solution casting method
And metal foil. As the resin film, a thermoplastic resin film is usually used, and specific examples thereof include a polyethylene terephthalate film, a polypropylene film, a polyethylene film, a polycarbonate film, a polyethylene naphthalate film, a polyarylate film and a nylon film. Among these resin films, a polyethylene terephthalate film and a polyethylene naphthalate film are preferable from the viewpoint of heat resistance, chemical resistance, peelability after lamination and the like. As the metal foil, for example, copper foil, aluminum foil, nickel foil,
Examples include chrome foil, gold foil, and silver foil. A copper foil, particularly an electrolytic copper foil or a rolled copper foil, is preferable because it has good conductivity and is inexpensive. The thickness of the support is not particularly limited, but is usually 1 μm to 150 μm, preferably 2 μm to 100 μm, more preferably 3 to 50 μm from the viewpoint of workability and the like.

Examples of the coating method include dip coating, roll coating, curtain coating, die coating and slit coating. The conditions for removing and drying the organic solvent are appropriately selected depending on the type of the organic solvent, the drying temperature is usually 20 to 300 ° C, preferably 30 to 200 ° C, and the drying time is usually 30 seconds to 1 hour, preferably Is 1
Minutes to 30 minutes.

The thickness of the film or sheet is usually 0.1.
˜150 μm, preferably 0.5 to 100 μm, more preferably 1.0 to 80 μm. When a film or sheet is desired to be obtained alone, it is peeled from the support after forming the film or sheet on the support. In addition, the varnish of the present invention can be impregnated on an organic synthetic back and a fiber base material such as glass fiber to form a prepreg.

The electric insulating film of the present invention is formed on an arbitrary substrate,
It is a cured product obtained by applying and drying the varnish of the present invention and then curing. A substrate having a conductor circuit layer is a laminate of the present invention. Specific examples of the substrate having the conductor circuit layer include an inner layer substrate such as a printed wiring board and a silicon wafer substrate, which is composed of the electric insulating layer (1) and the conductor circuit layer (a) formed on the surface thereof. Be done. The thickness of the inner layer substrate is usually 50 μm to 2 mm, preferably 60 μm to 1.6 mm, and more preferably 100.
μm to 1 mm.

The material of the electric insulation layer (1) constituting the inner layer substrate is not particularly limited as long as it is electrically insulating. Examples of the material of the electric insulating layer (1) include alicyclic olefin polymer, epoxy resin, maleimide resin, (meth) acrylic resin, diallyl phthalate resin, triazine resin,
Examples thereof include those obtained by curing a curable composition containing an aromatic polyether polymer, a cyanate ester polymer, a polyimide or the like. Further, the inner layer substrate may contain glass fibers, resin fibers or the like for improving strength. The material of the conductor circuit layer (a) forming the inner layer substrate is usually a conductive metal.

As a method for obtaining the electric insulating film and the laminate of the present invention, (A) the present invention obtained by applying the varnish of the present invention to a substrate having a conductor circuit layer, removing the organic solvent and drying. The method of curing the molded article of (1) or (B) the method of curing the molded article of the present invention molded on a film or sheet, after superposing it on a substrate having a conductor circuit layer by thermocompression bonding or the like. .. It is preferable to obtain the laminate by the method (B) from the viewpoints that the smoothness of the electric insulating layer can be secured and the formation of multiple layers is easy. Further, in the electric insulating film of the present invention, 500 μm confirmed by a scanning electron microscope.
In all directions, usually over 30 μm, preferably 25 μm
There are no large particles above, more preferably above 20 μm. The thickness of the electrically insulating film of the present invention is usually 0.1 to 2
The thickness is 00 μm, preferably 1 to 150 μm, more preferably 10 to 100 μm.

In the method (A), the method of applying the varnish of the present invention to the inner layer substrate is not particularly limited.
Examples thereof include a method of coating the substrate with the varnish of the present invention using a die coater, a roll coater, or a curtain coater. After applying the varnish to the substrate, 70 ~ 140 ℃, 1 ~
Dry for 30 minutes, usually 30 to 400 ° C., preferably 7
The electrical insulating film (electrical insulating layer (2)) of the present invention is formed by curing at 0 to 300 ° C, more preferably 100 to 200 ° C, usually 0.1 to 5 hours, preferably 0.5 to 3 hours. The obtained laminated body of the present invention is obtained.

In the method (B), in order to laminate the film or sheet which is the molded product of the present invention on the substrate, the film or sheet with a support is usually brought into contact with the inner layer substrate surface. Stacking, press laminator, press, vacuum laminator, vacuum press,
Heat press bonding using a pressure machine such as a roll laminator. The thermocompression bonding is preferably performed under vacuum in order to improve the embedding property in the wiring and suppress the generation of bubbles and the like. The temperature during thermocompression bonding is usually 30 to 250 ° C., preferably 7
0 ~ 200 ℃, the pressure is usually 10kPa ~ 20MP
a, preferably 100 kPa to 10 MPa, the pressure bonding time is usually 30 seconds to 5 hours, preferably 1 minute to 3 hours, usually 100 kPa to 1 Pa, preferably 40 kPa.
The atmosphere is depressurized to 10 Pa. After pressure bonding, the laminated body of the present invention on which the electric insulating film of the present invention (electrical insulating layer (2)) is formed is obtained in the same manner as described above. When the film or sheet with a support is laminated on a substrate, it may be cured with the support still attached, but it is usually cured after the support is peeled off.

In order to improve the adhesion between the inner layer substrate and the electric insulating layer (2), it is preferable to pretreat the inner layer substrate. As the pretreatment, a method of roughening the surface by contacting an alkaline sodium chlorite aqueous solution or permanganic acid with the inner layer substrate surface, after oxidizing the surface with an alkaline potassium persulfate aqueous solution, potassium sulfide-ammonium chloride aqueous solution, etc. Examples thereof include a reducing method, a method of depositing and roughening plating on the conductor circuit portion of the inner layer substrate, and a method of forming a primer layer with a triazine thiol compound or a silane compound. Among them, the method of forming a primer layer using a triazine thiol compound such as 2-di-n-butylamino-4,6-dimercapto-s-triazine is effective in preventing corrosion of copper when the conductor circuit is copper. It is preferable in that high adhesion can be obtained.

In this way, the electric insulating film (electric insulating layer (2)) of the present invention is formed on the inner layer substrate, and the laminate of the present invention having the electric insulating layer (2) as the outermost surface is obtained. When this laminate is obtained as a final circuit board, the electrical insulating film (electrical insulating layer (2)) of the present invention functions as a solder resist layer in the board.

Using the laminate of the present invention as an inner layer substrate, a new conductor circuit can be formed on the electric insulating layer (2) to obtain a multilayer circuit substrate. This multilayer circuit board has a laminated structure in which a layer made of the electrically insulating film of the present invention is formed on a board having a conductor circuit layer. Therefore, this multilayer circuit board is also the laminate of the present invention. There is no particular limitation on the method for manufacturing the multilayer circuit board, but the following method can be given as an example. An opening for forming a via hole is formed in the electric insulating layer (2), and then a metal thin film is formed on the surface of the electric insulating layer (2) and the inner wall surface of the opening for forming the via hole by a dry process (dry plating method) such as sputtering. After doing
A plating resist is formed on the metal thin film, and a plating film is further formed thereon by wet plating such as electrolytic plating.
After removing the plating resist, a conductor circuit (b) including a metal thin film and an electrolytic plated film is formed by etching. In order to enhance the adhesion between the electric insulation layer (2) and the conductor circuit (b), the surface of the electric insulation layer (2) is brought into contact with a liquid such as permanganate or chromic acid, or plasma treatment or the like is performed. be able to. A method for forming an opening for forming a via hole for connecting between the conductor circuit (a) and the conductor circuit (b) in the electrical insulating layer (2) is by a physical treatment such as drilling, laser or plasma etching. Good
It is also possible to use so-called photolithography, in which the film before forming the electric insulating layer by curing, which is the molded product of the present invention, is masked and photocured, and the uncured portion is removed, followed by curing. Among these methods, from the viewpoint that a finer via hole can be formed without deteriorating the characteristics of the insulating layer, a carbon dioxide gas laser, an excimer laser,
A laser method such as a UV-YAG laser is preferable.
Further, in the circuit board, part of the conductor circuit may be a metal power supply layer, a metal ground layer, or a metal shield layer.

The multilayer circuit board can be used as a printed wiring board for mounting a semiconductor element such as a CPU and a memory and other mounting parts in electronic equipment such as a computer and a mobile phone. In particular, those with fine wiring can be used as high-density printed wiring boards for high-speed computers,
It is suitable as a wiring board for mobile terminals used in a high frequency range.

[0068]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. In the examples, parts and% are based on weight unless otherwise specified. The evaluation method used in this example is as follows. (1) The molecular weight was measured as a polystyrene conversion value by gel permeation chromatography (GPC) using toluene as an organic solvent. (2) Hydrogenation Rate and Carboxyl Group Content Hydrogenation rate relative to the number of moles of unsaturated bonds in the polymer before hydrogenation (hydrogenation rate) and (anhydrous) maleic acid relative to the total number of monomer units in the polymer The molar ratio of the residue (carboxyl group content) was measured by ¹ H-NMR spectrum. (3) Glass transition temperature (Tg) It was measured by a differential scanning calorimetry (DSC method). (4) Average value of primary particle diameter of filler The major axis of 1000 fillers was measured with a scanning electron microscope, and the average of the obtained values was defined as the average value of the primary particle diameter of the filler. (5) Aspect Ratio of Filler Using a scanning electron microscope, the major axis and the minor axis of 1000 fillers were measured, and the average of the obtained values was applied to the following formula to determine the aspect ratio. Aspect ratio = (average of major axis) / (average of minor axis)

(6) Evaluation of secondary particle size The secondary particle size of the flame-retardant component present in the slurry and varnish was evaluated by the crushing test A method defined in JIS K5400. ○ when the grain size is 20 μm or less,
When the thickness was more than 20 μm and less than 30 μm, it was evaluated as Δ, and when it exceeded 30 μm, it was evaluated as x. For the evaluation of the secondary particle size of the flame retardant-imparting agent present in the electric insulating film (electric insulating layer on the substrate),
After cutting the insulating layer with an ion focusing beam, the cross section was observed with a scanning electron microscope in a range of 500 μm square, and when there was no aggregate size exceeding 20 μm, the aggregate size was The case where it exceeds 20 μm but does not exceed 30 μm is indicated by Δ, and the case where there is more than 30 μm is indicated by x.

(7) JPCA-BU01 is defined between the second and third electric insulating layers of a multilayer circuit board having a total of six layers on both sides, each having three electric insulating layers laminated on both surfaces of the insulating core material. After forming a pattern for evaluation between a solid conductor and a line, the sample was allowed to stand at 120 ° C. under saturated steam conditions while applying a DC voltage of 5.5V,
After 100 hours, the electric resistance value was measured. Electric resistance is 1
◎ 10 ⁹ ohms or more is ◎ 10 ⁸ ohms or more is 10 ⁹
Those having a resistance of less than 10 ohms were evaluated as ◯, those having a resistance of less than 10 ⁸ ohms without being short-circuited were evaluated as Δ, and those having a short circuit were evaluated as x.

(8) Hygroscopic change of permittivity According to the method of measuring permittivity defined in JPCA-BU01, the permittivity was measured under normal conditions and during moisture absorption. The dielectric constant in the normal state is
It is the value measured after leaving the base material produced according to the example of a size of 40 μm defined in JPCA-BU01 for 24 hours at 21 ° C. and 50% humidity. Dielectric constant when absorbing moisture is JPC
It is the value measured after immersing the base material produced according to the dimension example of 40 μm defined in A-BU01 in water at 21 ° C. for 24 hours. When the value expressed by (dielectric constant when absorbing moisture) / (dielectric constant in normal state) is 1.05 or less, ⊚, and the value is 1.
When the value exceeds 05 and is 1.1 or less, it is evaluated as ◯, when the value exceeds 1.1 and is 1.5 or less, it is evaluated as Δ, and when the value exceeds 1.5, it is evaluated as x. The base material used for this evaluation was manufactured as follows. The varnish used to manufacture the multilayer circuit board was applied to a polyethylene naphthalate film having a smooth surface by using a doctor blade, dried by heating at 120 ° C. for 10 minutes, and then placed in a nitrogen oven at 150 ° C. for 1 minute.
After leaving for 20 minutes, an electric insulating film was obtained. After aluminum is vapor-deposited on both sides of this electric insulation film to form a conductor, JPC
A base material for measurement having a size example of 40 μm specified in A-BU01 was manufactured.

(9) Evaluation of Flame Retardancy A conductor-free portion of a multilayer circuit board having a total of 6 layers on both sides of which three layers of electric insulating layers are laminated on both sides of the core material is 13
A test piece was prepared by cutting it into a strip having a length of 100 mm and a length of 100 mm. Methane gas is used with a pipe diameter of 9.5 mm and a pipe length of 10
Burned with a 0 mm Bunsen burner to a height of 19 mm
The flame was adjusted to, and the obtained test piece was exposed to flame until it ignited. The flame was removed immediately after ignition and the time during which the test piece was burning was measured. Immediately after the test piece was extinguished, it was contacted with flame until the test piece was ignited again. Remove the flame immediately after the second ignition,
The time during which the test piece was burning was measured. If the sum of the burning time of the first test piece and the burning time of the second test piece is within 5 seconds, it is "○", and if it exceeds 5 seconds and within 10 seconds, it is "△", and if it exceeds 10 seconds. It was evaluated as "x".

(10) Evaluation of storage stability of varnish Using an E-type viscometer, the viscosity a immediately after preparation of the varnish and the viscosity b after leaving at 25 ° C. for 72 hours were measured.
The viscosity increase rate is calculated from the viscosity a and the viscosity b, and the viscosity increase rate is 10% or less, "○", 10% to 30% or less, "△", 30% or more, "x". And (11) Evaluation of flatness of cured product The flatness of the cured product was measured by cutting a wiring board having a wiring thickness of 18 microns and measuring the thickness of the cured product layer with a scanning microscope.
In the evaluation, the difference between the thinnest part and the thickest part is 6 µm or less, "○", those exceeding 6 µm and 8 µm are "△", and those exceeding 8 µm are "x".

Example 1 Preparation of Micronized Polymelic Acid Melamine Salt Slurry A 55% of primary particles having a major axis of more than 10 μm, average major axis of 17 μm, 300 parts of polyphosphoric acid melamine salt having an aspect ratio of 13 were treated with xylene, 1020 parts, and cyclopentanone. 6
3 parts in a separable flask with 80 parts of mixed organic solvent
The mixture was stirred with a single-blade stirring blade to obtain a slurry of 15 wt% melamine polyphosphate salt. When the resulting melamine polyphosphate salt slurry was dried and observed with a scanning microscope, the primary particles had 55% particles having a major axis of more than 10 μm, an average major axis of 17 μm, and an aspect ratio of 13, similar to the raw material. 2000 parts of the obtained slurry was pulverized for 120 minutes by using a horizontal wet disperser filled with 0.4% of zirconia beads at 83% by volume while circulating for a residence time of 18 minutes to obtain a finely divided melamine polyphosphate polysulfate slurry. A
Got When the obtained melamine polyphosphate salt slurry A was dried and observed with a scanning microscope, 0.5% of the primary particles had a major axis of more than 10 μm, and an average major axis of 1.3 μ.
m and the aspect ratio was 1.6. The obtained slurry A
The secondary particle diameter of was evaluated to be x.

Preparation of Micronized Melamine Polyphosphate Slurry B
In a separable flask, 12 parts of diisopropoxyaluminum monooleyl acetoacetate was added to 2000 parts of pulverized melamine salt of polyphosphoric acid salt A, and the mixture was stirred for 15 minutes at 25 ° C. with a 3-blade stirring blade for surface treatment of polyphosphoric acid. An acid melamine salt slurry B was obtained. The obtained slurry B
The secondary particle size was evaluated to be ◯.

8-ethyl-tetracyclo [4.4.0.
1 ^2,5 . 1 ^7,10 ] -dodeca-3-ene was subjected to ring-opening polymerization, followed by hydrogenation reaction to obtain a number average molecular weight (Mn).
= 31,200, weight average molecular weight (Mw) = 55,80
A hydrogenated polymer having 0 and Tg of about 140 ° C. was obtained. The hydrogenation rate of the obtained polymer was 99% or more. 100 parts of the obtained polymer, 40 parts of maleic anhydride and 5 parts of dicumyl peroxide were dissolved in 250 parts of t-butylbenzene,
The reaction was carried out at 140 ° C for 6 hours. The obtained reaction product solution was poured into 1000 parts of isopropyl alcohol to coagulate the reaction product to obtain a maleic acid-modified hydrogenated polymer. The modified hydrogenated polymer was vacuum dried at 100 ° C. for 20 hours. The molecular weight of this modified hydrogenated polymer was Mn = 33,
200, Mw = 68,300 and Tg was 170 degreeC. The maleic acid group content was 25 mol%.

100 parts of the modified hydrogenated polymer, 1,3-
50 parts of diallyl-5-glycidyl isocyanurate, 5 parts of dicumyl peroxide, 200 parts of the surface-treated micronized melamine polyphosphate salt slurry B, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl). )
Phenyl] benzotriazole 5 parts and hydrogenated bisphenol A type epoxy resin (trade name: EPICLONE E
XA-7015, manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent = 210 g) 20 parts, 0.1 part of 1-benzyl-2-phenylimidazole was dissolved in a mixed organic solvent consisting of 40 parts of xylene and 25 parts of cyclopentanone. Varnish A
Got

Using a die coater, the varnish was 3
It is applied to a polyethylene naphthalate film (carrier film) having a thickness of 00 mm and a thickness of 40 μm, and then dried in a nitrogen oven at 120 ° C. for 10 minutes to give a resin thickness of 45.
A dry film with a carrier film of μm was obtained.

On the other hand, 2-di-n-butylamino-4,6
A 0.1 wt% isopropyl alcohol solution of dimercapto-s-triazine was prepared, and the thickness of the solution in which an inner layer circuit having a wiring width and a wiring distance of 50 μm, a conductor thickness of 18 μm and a surface microetched was formed. A 0.8 mm double-sided copper-clad substrate (core material obtained by impregnating glass cloth with a varnish containing a glass filler and a halogen-free epoxy resin) was immersed at 25 ° C. for 1 minute, and then at 90 ° C. for 15 minutes. A primer layer was formed by drying in a nitrogen-substituted oven to obtain an inner layer substrate.

On the above-mentioned inner layer substrate, the above-mentioned dry film with a carrier film was laminated on both sides of the double-sided copper-clad substrate with the resin side facing inward. This was depressurized to 200 Pa using a vacuum laminator equipped with heat-resistant rubber press plates at the top and bottom as a primary press, and the temperature was reduced to 11
Thermocompression bonding was performed for 60 seconds at 0 ° C. and a pressure of 0.5 MPa. Then, using a heat proof rubber press plate as a secondary press, a vacuum laminator equipped with a heat proof rubber press plate covered with a metal press plate at the top and bottom was used for 20 minutes.
The pressure was reduced to 0 Pa, and thermocompression bonding was performed at a temperature of 140 ° C. and a pressure of 1.0 MPa for 60 seconds. Then, only the polyethylene naphthalate film was peeled off and left in a nitrogen oven at 150 ° C. for 120 minutes to form an electric insulating layer on the inner layer substrate.

On the insulating layer portion of the obtained laminated plate, UV-
A via hole for interlayer connection having a diameter of 30 μm was formed using a YAG laser third harmonic. The substrate on which the via holes are formed has a frequency of 13.56 MHz, an output of 100 W, and a gas pressure of 0.5.
Substrate surface temperature of approx. 130 with argon plasma of 8Pa
Hold at 0 ° C and expose for 10 minutes. Next, the plasma-treated circuit board was subjected to nickel sputter processing at an output of 500 W and a gas pressure of 0.8 Pa to form a nickel film having a thickness of 0.1 μm, and then subjected to copper sputter processing at an output of 500 W and a gas pressure of 0.8 Pa, Form a copper thin film with a thickness of 0.3 μm,
A laminated plate having a metal thin film was obtained. A commercially available photosensitive dry film was thermocompression-bonded to the surface of the laminate, and a mask having a predetermined pattern was brought into close contact with the dry film, exposed, and developed to obtain a resist pattern. Next, electrolytic copper plating was applied to the non-resist forming portion to form an electrolytic copper plating film having a thickness of 18 μm. Next, the resist pattern was stripped off with a stripping solution, and an etching treatment was performed with a mixed solution of cupric chloride and hydrochloric acid to form a wiring pattern composed of the metal thin film and the electrolytic copper plated film. Finally, an annealing treatment was carried out at 170 ° C. for 30 minutes to obtain a multilayer circuit board with wiring patterns on both surfaces of two layers.

The outer layer of the multilayer circuit board with wiring patterns having two layers on both sides obtained as described above was used as the first layer, and was used as the inner layer circuit board described above. A multilayer circuit board having a total of 6 layers was obtained. The evaluation results are shown in Table 1.

Example 2 Production of Micronized Polymelic Acid Melamine Salt Slurry C 55% of primary particles having a major axis of more than 10 μm, average major axis of 17 μm, 300 parts of polyphosphoric acid melamine salt having an aspect ratio of 13, 300 parts of xylene, cyclopenta Non 6
80 parts, 12 parts of diisopropoxy aluminum monooleyl acetoacetate was crushed for 60 minutes while circulating with a horizontal wet disperser filled with 83% by volume of 0.4 mm zirconia beads with a residence time of 18 minutes,
Micronized melamine polyphosphate salt slurry C was obtained. When the obtained melamine polyphosphate salt slurry was dried and observed with a scanning microscope, primary particles had a major axis of more than 10 μm of 0.3%, an average major axis of 1.1 μm, and an aspect ratio of 1.4. When the secondary particle diameter of the obtained slurry C was evaluated, it was ◯.

A multi-layer circuit board was obtained in the same manner as in Example 1 except that the melamine polyphosphate salt slurry C was used in place of the surface-treated micronized melamine polyphosphate salt slurry B.
The evaluation results are shown in Table 1.

Example 3 Instead of 100 parts of the modified hydrogenated polymer, an epoxy resin YD was used.
A multilayer circuit board was obtained in the same manner as in Example 1 except that a mixture of 30 parts of -7011 (manufactured by Toto Kasei Co., Ltd.) and 30 parts of polyamide resin Macrometol 6217 (manufactured by Henkel Hakusui Co., Ltd.) was used. The evaluation results are shown in Table 1.

Comparative Example 1 A multilayer circuit board was obtained in the same manner as in Example 3, except that the melamine polyphosphate salt slurry A was used in place of the surface-treated micronized melamine polyphosphate salt slurry B. The evaluation results are shown in Table 1.

[0087]

[Table 1]

Example 4 Production of Micronized Melamine Polyphosphate Phosphate Slurry D 1000 g of the slurry B obtained above was mixed with silica gel (trade name: Wakogel C-300H as a porous substance).
G, manufactured by Wako Pure Chemical Industries, Ltd., particle size: 40-60 μm, pore size: 7
(30 nm), and after standing at 25 ° C. for 24 hours, a capsule filter (final filter containing filler:
The porous substance was separated by filtration using 10 μm, manufactured by Roki Techno Co., Ltd. to obtain a finely divided melamine salt of polyphosphoric acid salt D.

Modified hydrogenated polymer 100 obtained in Example 1
Part, bisphenol A bis (propylene glycol glycidyl ether) ether 37.5 parts, 1,3-diallyl-5- (2-hydroxy-3-phenoxypropyl)
-1,3,5-triazine-2,4,6 (1H, 3H,
5H) -trione 12.5 parts, dicumyl peroxide 6
Parts, the surface-treated micronized melamine polyphosphate salt slurry D described above 200 parts, 2- [2-hydroxy-3,5-
Varnish D was prepared by dissolving 5 parts of bis (α, α-dimethylbenzyl) phenyl] benzotriazole and 0.1 part of 1-benzyl-2-phenylimidazole in a mixed organic solvent consisting of 120 parts of xylene and 80 parts of cyclopentanone. Obtained. The storage stability of the obtained varnish D was evaluated. The evaluation results are shown in Table 2.

The varnish D thus obtained was allowed to stand at 25 ° C. for 72 hours, and then a die coater was used to obtain a thickness of 4 mm × 300 mm.
It is applied to a polyethylene naphthalate film (carrier film) of 0 μm, and then 120 in a nitrogen oven.
It was dried at 0 ° C. for 10 minutes to obtain a dry film with a carrier film having a resin thickness of 45 μm.

On the other hand, 2-di-n-butylamino-4,6
A 0.1 wt% isopropyl alcohol solution of dimercapto-s-triazine was prepared, and the thickness of the solution in which an inner layer circuit having a wiring width and a wiring distance of 50 μm, a conductor thickness of 18 μm and a surface microetched was formed. A 0.8 mm double-sided copper-clad substrate (core material obtained by impregnating glass cloth with a varnish containing a glass filler and a halogen-free epoxy resin) was immersed at 25 ° C. for 1 minute, and then at 90 ° C. for 15 minutes. A primer layer was formed by drying in a nitrogen-substituted oven to obtain an inner layer substrate.

On the above-mentioned inner layer substrate, the above-mentioned dry film with a carrier film was laminated on both sides of the double-sided copper-clad substrate with the resin side facing inward. This was depressurized to 200 Pa using a vacuum laminator equipped with heat-resistant rubber press plates at the top and bottom as a primary press, and the temperature was reduced to 11
Thermocompression bonding was performed for 60 seconds at 0 ° C. and a pressure of 0.5 MPa. Then, using a vacuum laminator having a heat-resistant rubber press plate covered with a metal press plate as a secondary press, the pressure was reduced to 200 Pa, the temperature was 140 ° C., and the pressure was 1.0.
It thermocompression-bonded by MPa for 60 seconds. Then, only the polyethylene naphthalate film was peeled off and left in a nitrogen oven at 140 ° C. for 30 minutes, 170 ° C. for 60 minutes to form an electrical insulating layer on the inner layer substrate.

A UV-YAG laser beam machine using a 38 μm aperture (MO
DEL 5310: Electro Scientf
icIndustries, Inc. Manufactured), processing conditions, frequency 40 kHz, output 0.6 W, shot number 40
Then, a via hole for exposing a terminal and an interlayer connection having a diameter of 40 μm was formed. The substrate on which the via hole is formed has a frequency of 13.
The substrate surface temperature is maintained at about 130 ° C. in argon plasma of 56 MHz, output of 100 W and gas pressure of 0.8 Pa,
Exposed for 10 minutes.

Next, the plasma-treated circuit board is output 5
Nickel sputter process at 00W, gas pressure 0.8Pa,
Form a nickel film with a thickness of 0.1 μm, and then output 5
Copper spattering was performed at 00 W and gas pressure of 0.8 Pa, and the thickness was 0.8.
A 3 μm copper thin film was formed to obtain a laminated plate having a metal thin film. A commercially available photosensitive dry film was thermocompression-bonded to the surface of the laminate, and a mask having a predetermined pattern was brought into close contact with the dry film, exposed, and developed to obtain a resist pattern. Next, electrolytic copper plating was applied to the non-resist forming portion to form an electrolytic copper plating film having a thickness of 18 μm. Next, the resist pattern was stripped off with a stripping solution, and an etching treatment was performed with a mixed solution of cupric chloride and hydrochloric acid to form a wiring pattern composed of the metal thin film and the electrolytic copper plated film. And finally, 1
Annealing treatment was performed at 70 ° C. for 30 minutes to obtain a multilayer circuit board A with a wiring pattern having two layers on both sides. The flatness of the obtained multilayer circuit board with a two-layer double-sided wiring pattern was evaluated. The evaluation results are shown in Table 2.

Example 5 Instead of 100 parts of modified hydrogenated polymer, epoxy resin YD was used.
A varnish was obtained in the same manner as in Example 4 except that a mixture of 30 parts of -7011 (manufactured by Toto Kasei Co., Ltd.) and 30 parts of polyamide resin Macrometol 6217 (manufactured by Henkel Hakusui Co., Ltd.) was used to obtain a multilayer circuit board. The evaluation results are shown in Table 2.

[0096]

[Table 2]

From these facts, it can be seen that when the varnish is brought into contact with the porous substance, the viscosity of the varnish does not increase, so that a film having excellent flatness can be stably obtained even after long-term storage.

[0098]

EFFECTS OF THE INVENTION By using the varnish of the present invention, it is possible to easily obtain a multilayer circuit board which is not easily electrically affected by environmental changes and has excellent insulating properties. Since it is also highly flame-retardant, a multilayer circuit board obtained using this varnish is a printed material for mounting semiconductor devices such as CPUs and memories, and other mounting components in electronic devices such as computers and mobile phones. Can be used as a wiring board. Further, by bringing the varnish into contact with the porous substance, a varnish having excellent storage stability can be obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08J 5/18 CER C08J 5/18 CER 5E346 CEZ CEZ 5G305 C08K 5/16 C08K 5/16 9/00 9 / 00 C08L 45/00 C08L 45/00 65/00 65/00 C09D 5/25 C09D 5/25 7/12 7/12 145/00 145/00 C09K 21/00 C09K 21/00 H01B 3/30 H01B 3 / 30 M N H05K 3/46 H05K 3/46 T F term (reference) 4F071 AA03 AA21 AA39 AC12 AE02 AE07 AE19 AF39 BA02 BA03 BB02 BC01 4F100 AA20B AH03B AH03H AH08B AH08H AK01B AK02B AK42 AL05B AL07 AT00A BA02 CA02B CA08B DE01B EJ67B GB43 JB09B JB12B JG04B JG05 JJ07 JM02B JM10B 4H028 AA40 AA42 BA05 4J002 BF051 BG041 BG051 BH021 BK001 CD001 CE001 CH061 CL012 CM021 CM041 DE077 DE127 DE147 DK007 EN036 EN 046 EN076 EN126 ER006 ER027 EU186 EW047 EW137 FB087 FB167 FD137 FD142 FD146 FD150 HA06 4J038 CM001 KA03 KA06 KA14 NA15 5E346 AA05 AA06 AA12 AA26 AA CA25 CA13 CA11 CA11 CA11 CA21 CA11 CA25 CA11 CA11 CA11 CA11 CA11 CA11 CA11 CA11 CA11 CA11

Claims (15)

[Claims] 1. A curable varnish containing an insulating polymer, a curing agent, a flame retardant and an organic solvent, wherein (1) the flame retardant is obtained by surface-treating a flame retardant imparting agent with a coupling agent. (2) A varnish obtained by (2) having a secondary particle size of 30 μm or less. 2. The varnish according to claim 1, wherein the coupling agent is a metal chelate compound. 3. The varnish according to claim 1, wherein the flame retardancy-imparting agent is a halogen-free compound. 4. The varnish according to claim 1, wherein the insulating polymer is an alicyclic olefin polymer. 5. The curing agent is a nitrogen-containing compound.
The varnish according to any one of 4 above. 6. A molded product obtained by drying the varnish according to claim 1. 7. The molded product according to claim 6, which is a film or a sheet. 8. An electric insulating film obtained by curing the molded product according to claim 6. 9. A laminate in which an electrically insulating layer made of the electrically insulating film according to claim 8 is formed on a substrate having a conductor circuit layer. 10. The laminate according to claim 9, wherein the electrically insulating layer made of an electrically insulating film is obtained by thermocompression bonding the molded article according to claim 7. 11. A flame retardant slurry comprising a flame retardant obtained by bringing a flame retardant-imparting agent into contact with a coupling agent, and an organic solvent. 12. The flame retardant slurry according to claim 11, wherein the secondary particle diameter of the particles present in the slurry is 30 μm or less. 13. A method for preparing a varnish according to claim 1, wherein the slurry according to claim 11 or 12 is mixed with an insulating polymer and a curing agent. 14. The method for preparing a varnish according to claim 13, wherein after the slurry and the porous substance are brought into contact with each other, the porous substance is removed, and then the slurry, the insulating polymer and the curing agent are mixed. 15. The method for preparing a varnish according to claim 14, wherein the porous substance is silica gel.