JP2010082858A - Film for multilayered printed circuit board and multilayered printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film for a multilayered printed circuit board showing excellent fire retardant properties even in a case that a polymer containing a chlorine atom and a bromine atom or a curable resin composition not containing a fire retardant or the like is used and excellent even in electric characteristics or wiring embedding properties. <P>SOLUTION: The film for the multilayered printed circuit board is composed of an intermediate layer comprising a fire retardant organic polymer material film and the first and second outer layers laminated on both sides of the intermediate layer and formed of the curable resin composition containing an alicyclic olefin polymer having a functional group and a curing agent. The thickness (t<SB>M</SB>) of the intermediate layer is 3-24 μm, the thickness (t<SB>O1</SB>) of the first outer layer is 1-20 μm, the thickness (t<SB>O2</SB>) of the second outer layer is 6-20 μm and the ratio [(t<SB>O1</SB>+t<SB>O2</SB>)/t<SB>M</SB>] of the sum of the thicknesses of the first and second outer layers and the thickness of the intermediate layer is 0.5-3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multilayer printed circuit board film and a multilayer printed circuit board, and more specifically, in the case of using a curable resin composition that does not contain a polymer containing a chlorine atom or a bromine atom or a flame retardant. In particular, the present invention relates to a multilayer printed circuit board film that exhibits excellent flame retardancy and also has excellent electrical characteristics and wiring embedding properties, and a multilayer printed circuit board using the same.

  In recent years, with the pursuit of downsizing, multi-functionality, high-speed communication, etc. of electronic devices, multilayer printed circuit boards have been required to be thinner and more flexible. Therefore, as a method for producing a multilayer printed circuit board, a technique for forming a multilayer printed circuit board by laminating resin films has attracted attention. Multilayer printed circuit boards made by laminating resin films are known to have weaknesses in mechanical strength, heat resistance, and flame retardancy compared to the case of using prepregs manufactured using glass cloth or the like. In recent years, techniques for improving this weakness have been reported.

  For example, Patent Documents 1 to 3 include a layer made of a resin having excellent heat resistance and mechanical strength such as polyimide, a thermosetting resin composition containing a resin containing a functional group and a curing agent. It is disclosed that a film formed by laminating a layer is preferably used for manufacturing a multilayer printed circuit board and the like because it is excellent in mechanical strength and heat resistance and is easily laminated.

  Here, Patent Document 1 discloses that the composite film with a conductive layer has V-0 flame retardancy according to the UL standard. This flame retardancy is as much as 18 μm on the composite film. It is measured after providing a certain conductive layer, and without such a conductive layer, such high flame retardancy cannot be exhibited. Due to the recent demand for thinner multilayer printed circuit boards, the density of wiring has increased and the amount of heat generated from the wiring has increased, so the multilayer printed circuit board film has no conductive layer. Even if it exists, the high flame retardance which shows high flame retardance is calculated | required. Therefore, further improvement in flame retardancy has been desired for the composite film described in Patent Document 1.

  By the way, as a technique for improving the flame retardancy of a resin film used for the production of a multilayer printed circuit board, as disclosed in Patent Document 2 mentioned above, a thermosetting resin composition is brominated with a brominated epoxy resin or the like. A technique for forming a thermosetting resin layer using a resin containing atoms (or chlorine atoms) and a technique for blending a flame retardant into a thermosetting resin composition are known.

  However, since the used multilayer printed circuit board is usually incinerated, the chlorine atom or bromine generally used as a flame retardant or a resin containing a bromine atom as disclosed in Patent Document 2 is used. When halogen-based flame retardants containing atoms are used, halogen-based harmful substances generated during incineration become a problem. Therefore, a multilayer printed circuit board film containing no chlorine atom or bromine atom is desired.

  Thus, as a technique for solving the problem caused by the multilayer printed circuit board film containing chlorine atoms and bromine atoms, as disclosed in Patent Document 4, for example, a so-called non-halogen system that does not contain halogen atoms. A technique using a flame retardant is known. However, when such a non-halogen flame retardant is added to the thermosetting resin layer of the multilayer printed circuit board film, there arises a problem that the environmental resistance and the adhesion between the thermosetting resin layer and the conductive circuit deteriorate. There was a thing. Therefore, a multilayer printed circuit board film excellent in flame retardancy has been eagerly desired without requiring a thermosetting resin composition containing a polymer containing a chlorine atom or a bromine atom, a flame retardant, or the like.

JP 11-129399 A International Publication No. 01/097582 Pamphlet International Publication No. 05/025857 Pamphlet JP 2007-9169 A

  The object of the present invention is to provide excellent flame retardancy even when a curable resin composition containing no chlorine or bromine atom-containing polymer or flame retardant is used, An object of the present invention is to provide a multilayer printed circuit board film having excellent wiring embedding properties.

  As a result of diligent research to achieve the above object, the present inventor has found that a multilayer printed circuit board film has an alicyclic olefin having a functional group on both sides of an intermediate layer made of a flame retardant organic polymer material film. A layer composed of a curable resin composition containing a polymer and a curing agent is laminated, and the thickness of each layer has a specific relationship so that chlorine atoms and bromine atoms Multilayer printed circuit board having excellent flame retardancy and excellent electrical characteristics and wiring embedding even when a curable resin composition containing no polymer or flame retardant is used. It was found that a film for use was obtained. The present invention has been completed based on these findings.

Thus, according to the present invention, an intermediate layer composed of a flame retardant organic polymer material film that is V-0, V-1, VTM-0, or VTM-1 in a test compliant with the UL94 standard, A multilayer printed circuit board film comprising a first outer layer and a second outer layer, each of which is formed of a curable resin composition comprising an alicyclic olefin polymer having a functional group and a curing agent, laminated on both sides. The intermediate layer thickness (t _M ) is 3 to 24 μm, the first outer layer thickness (t _O1 ) is 1 to 20 μm, and the second outer layer thickness (t _O2 ) is 6 to 20 μm. And the ratio of the sum of the thicknesses of the first outer layer and the second outer layer to the thickness of the intermediate layer ((t _O1 + t _O2 ) / t _M ) is 0.5 to 3. A film for a substrate is provided.

  In this multilayer printed circuit board film, the alicyclic olefin polymer having a functional group preferably does not contain chlorine atoms and bromine atoms. Moreover, it is preferable that curable resin composition is a thing which does not contain a flame retardant.

  Further, according to the present invention, the above-mentioned multilayer printed circuit board film is applied to a substrate having a conductive circuit having a thickness of 5 to 10 μm on the surface, the surface of the substrate having the conductive circuit and the multilayer printed circuit board. The film is laminated so as to be in contact with the second outer layer of the film, and further, the first outer layer and the second outer layer of the multilayer printed circuit board film are cured, and the conductive circuit is formed on the first outer layer of the multilayer printed circuit board film. A multilayer printed circuit board having a structure obtained by forming the substrate is provided.

  Furthermore, according to the present invention, the above-mentioned multilayer printed circuit board film is applied to a substrate having a conductive circuit having a thickness of 5 to 10 μm on the surface, the surface of the substrate having the conductive circuit and the multilayer printed circuit board. A step of laminating the second outer layer of the film in contact, a step of curing the first outer layer and the second outer layer of the multilayer printed circuit board film, and a conductive circuit on the first outer layer of the multilayer printed circuit board film. A method of manufacturing a multilayer printed circuit board.

  According to the present invention, even when a curable resin composition containing no chlorine or bromine atom-containing polymer or flame retardant is used, excellent flame retardancy is exhibited, and A multilayer printed circuit board film having excellent wiring embedding properties can be obtained.

  The multilayer printed circuit board film of the present invention is a film used for constituting a multilayer printed circuit board, and is a film comprising at least three layers of an intermediate layer, a first outer layer and a second outer layer. The intermediate layer constituting this film is composed of a flame retardant organic polymer material film which is V-0, V-1, VTM-0 or VTM-1 in a test based on the UL94 standard. As a flame retardant organic polymer material for forming the flame retardant organic polymer material film constituting the intermediate layer, the flame retardant organic polymer material is excellent in flame retardancy, and the flame retardancy when made into a film is a test conforming to the UL94 standard. Although it will not specifically limit if it is an organic polymer material used as V-0, V-1, VTM-0, or VTM-1, A polyimide, an aramid resin, and a liquid crystal polymer are illustrated. In addition, a commercially available flame-retardant organic polymer material film can be suitably used for forming an intermediate layer of the multilayer printed circuit board film of the present invention. For example, a polyimide film manufactured by Ube Industries, Ltd. (trade name) Upilex), Toray DuPont polyimide film (trade name Kapton), Kaneka polyimide film (trade name Apical), Toray Aramid resin film (trade name Mikutron), Japan Gore-Tex liquid crystal polymer A film (trade name BIAC) or the like can be suitably used. Since these flame retardant organic polymer material films serve as the intermediate layer of the multilayer printed circuit board film of the present invention, a film having a thickness corresponding to the thickness of the intermediate layer described later is selected and used. It ’s fine.

  In the multilayer printed circuit board film of the present invention, the first outer layer and the second outer layer are laminated on both sides of the intermediate layer (that is, the first outer layer is laminated on one side of the intermediate layer, and the other outer layer of the intermediate layer is laminated). A second outer layer is laminated on the surface side). The first outer layer and the second outer layer are formed of a curable resin composition containing an alicyclic olefin polymer having a functional group and a curing agent, respectively. Here, the alicyclic olefin polymer having a functional group used in the present invention is a polymer having a repeating unit derived from an olefin having an alicyclic structure (alicyclic olefin) and having a functional group. is there.

  Examples of the alicyclic structure that can be contained in the alicyclic olefin polymer having a functional group used in the present invention include a cycloalkane structure and a cycloalkene structure. From the viewpoint of mechanical strength, heat resistance, and the like, A cycloalkane structure is preferable, and a norbornane structure is particularly preferable. Examples of the alicyclic structure include monocycles, polycycles, condensed polycycles, bridged rings, and polycycles formed by combining these. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, Various characteristics of heat resistance and moldability are highly balanced and suitable. In addition, the alicyclic olefin polymer having a functional group used in the present invention is usually thermoplastic.

  The ratio of the repeating unit derived from the alicyclic olefin in the alicyclic olefin polymer having a functional group is not particularly limited, but is usually 30 to 100% by weight, preferably 50 to 100% by weight, more preferably 70 to 100%. % By weight. When the ratio of the repeating unit derived from the alicyclic olefin is excessively small, the heat resistance is inferior, which is not preferable. The repeating unit other than the repeating unit derived from the alicyclic olefin is not particularly limited and is appropriately selected depending on the purpose.

  Although the functional group which the alicyclic olefin polymer which has a functional group has is not specifically limited, It is preferable that it is a functional group which can react with the functional group which the hardening | curing agent to use and can form a bond. Specific examples of functional groups possessed by the alicyclic olefin polymer include hydroxyl group, carboxyl group, alkoxyl group, epoxy group, glycidyl group, oxycarbonyl group, carbonyl group, amino group, ester group, carboxylic anhydride group, etc. In particular, a carboxyl group or a carboxylic anhydride group is preferable. In addition, the alicyclic olefin polymer having a functional group may have two or more kinds of functional groups. In addition, the functional group of the alicyclic olefin polymer may be directly bonded to an atom constituting the main chain of the polymer, but other divalent groups such as a methylene group, an oxy group, an oxycarbonyloxyalkylene group, and a phenylene group. It may be bonded via the group. The amount of the functional group in the alicyclic olefin polymer having a functional group is not particularly limited, but is usually 5 to 60 mol%, preferably based on the number of moles of all repeating units constituting the alicyclic olefin polymer. Is 10 to 50 mol%.

  The alicyclic olefin polymer having a functional group used in the present invention preferably does not contain a chlorine atom and a bromine atom. Since the multilayer printed circuit board film of the present invention exhibits sufficient flame retardancy based on its configuration, sufficient flame retardancy can be ensured even when a polymer containing no chlorine or bromine atoms is used. it can. Therefore, by using a polymer that does not contain chlorine atoms and bromine atoms, even if the multilayer printed circuit board film is incinerated, it has a feature that no halogen-based harmful substances are generated.

  In general, alicyclic olefin polymers are obtained by addition polymerization or ring-opening polymerization of alicyclic olefins, and hydrogenation of unsaturated bond portions as necessary, or addition polymerization or ring-opening polymerization of aromatic olefins. And hydrogenating the aromatic ring portion of the polymer. And the alicyclic olefin polymer which has a functional group used by this invention, for example, adds another monomer as needed and polymerizes the alicyclic olefin which has a functional group as needed. (2) By copolymerizing an alicyclic olefin having no functional group with a monomer having a functional group, (3) an aromatic olefin having a functional group may be converted to another monomer as required. (4) copolymerizing an aromatic olefin having no functional group with a monomer having a functional group, by hydrogenating the aromatic ring portion of the resulting polymer. By hydrogenating the aromatic ring portion of the polymer obtained by (5), or (5) introducing a functional group-containing compound into the alicyclic olefin polymer having no functional group, or (6) (1) above The functional group of the alicyclic olefin polymer having a functional group (for example, a carboxylic acid ester group) obtained as in (5) is converted into another functional group (for example, a carboxyl group) by, for example, hydrolysis. Can be obtained. In the present invention, the polymer obtained by the method (1) is particularly preferably used.

Specific examples of the alicyclic olefin having a functional group include 8-hydroxycarbonyltetracyclo [4.4.0.1 ^2,5 . ^{17, 10} ] dodec-3-ene, 5-hydroxycarbonylbicyclo [2.2.1] hept-2-ene, 5-methyl-5-hydroxycarbonylbicyclo [2.2.1] hept-2-ene , 5-carboxymethyl-5-hydroxycarbonylbicyclo [2.2.1] hept-2-ene, 8-methyl-8-hydroxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-carboxymethyl-8-hydroxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 5-exo-6-endo-dihydroxycarbonylbicyclo [2.2.1] hept-2-ene, 8-exo-9-endo-dihydroxycarbonyltetracyclo [4. 4.0.1 ^2,5 . Alicyclic olefins having a carboxyl group such as ^{17, 10} ] dodec-3-ene; bicyclo [2.2.1] hept-2-ene-5,6-dicarboxylic anhydride, tetracyclo [4.4. 0.1 ^2,5 . 1 ^7,10 ] dodec- ³ -ene-8,9-dicarboxylic anhydride, hexacyclo [6.6.1.1 ^3,6 . 1 ^10,13 . 0 ^2,7 . 0 ^9,14] heptadec-4-ene-11,12 alicyclic olefin having a carboxylic acid anhydride group, such as a dicarboxylic acid anhydride; 8-methyl-8-methoxycarbonyltetracyclo [4.4.0. 1 ^2,5 . ^{17, 10} ] dodec-3-ene, 5-methoxycarbonyl-bicyclo [2.2.1] hept-2-ene, 5-methyl-5-methoxycarbonyl-bicyclo [2.2.1] hept-2 -An alicyclic olefin having a carboxylic acid ester group such as ene; and the like. These may be used alone or in combination of two or more.

Specific examples of the alicyclic olefin having no functional group include bicyclo [2.2.1] hept-2-ene (common name: norbornene), 5-ethyl-bicyclo [2.2.1] hept-2. -Ene, 5-butyl-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, tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (common name: di cyclopentadiene), tetracyclo ^{[8.4.0.1 11,14.} 0 ^2,8 ] tetradeca-3,5,7,12,11-tetraene, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dec-3-ene (common 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 ] dodec-3-ene, 8-ethylidene-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-vinyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-propenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-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 . 0 ^2,7 ] pentadeca-4,11-diene, cyclopentene, cyclopentadiene, 1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene, 8-phenyl-tetracyclo [4.4. 0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 7,10-methano-6b, 7,10,10a-tetrahydrofluoranthene, etc., and these may be used alone or in combination of two or more. You may use together.

  Examples of aromatic olefins (having no functional group) include styrene, α-methylstyrene, divinylbenzene, and the like, and these may be used alone or in combination of two or more. .

  Examples of the monomer having a functional group other than the alicyclic olefin having a functional group that can be copolymerized with an alicyclic cycloolefin or an aromatic olefin include an ethylenically unsaturated compound having a functional group. Specific examples thereof include acrylic acid, methacrylic acid, α-ethylacrylic acid, 2-hydroxyethyl (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, endocis-bicyclo [2.2.1] hept- Unsaturated carboxylic acid compounds such as 5-ene-2,3-dicarboxylic acid and methyl-endocis-bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid; maleic anhydride, butenyl succinic anhydride Unsaturated carboxylic acid anhydrides such as acid, tetrahydrophthalic anhydride, citraconic anhydride, etc., and these may be used alone. And it may be used in combination of two or more thereof.

  Examples of the monomer having no functional group other than the alicyclic olefin that can be copolymerized with the alicyclic cycloolefin or the aromatic olefin include ethylenically unsaturated compounds having no functional group. Specific examples include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, and 4-methyl-1. -Pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene , 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, etc., ethylene or α-olefin having 2 to 20 carbon atoms; 1,4- And the like; hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene nonconjugated dienes such. These may be used alone or in combination of two or more.

  The polymerization method of alicyclic olefin and aromatic olefin, and the hydrogenation method performed as necessary are not particularly limited, and can be performed according to a known method.

  The molecular weight of the alicyclic olefin polymer having a functional group used in the present invention is not particularly limited, but is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) using cyclohexane or toluene as a solvent ( Mw), usually in the range of 1,000 to 1,000,000, preferably 5,000 to 500,000, more preferably 10,000 to 250,000. When the weight average molecular weight (Mw) of the alicyclic olefin polymer having a functional group is in this range, the heat resistance of the resulting multilayer printed circuit board film, the smoothness of the surface of the molded product, and the like are preferably balanced. In addition, the method of adjusting the weight average molecular weight (Mw) of the alicyclic olefin polymer having a functional group may be in accordance with a conventional method. For example, the ring-opening polymerization of the alicyclic olefin is ruthenium-based, titanium-based, tungsten-based. For example, a method of adding about 0.1 to 10 mol% of a molecular weight regulator such as a vinyl compound or a diene compound with respect to the total amount of the monomer may be used. When a large amount of the molecular weight modifier is used, a polymer having a low Mw is obtained. Examples of such molecular weight modifiers include vinyl compounds such as α-olefin compounds such as 1-butene, 1-pentene, 1-hexene and 1-octene; styrene compounds such as styrene and vinyltoluene; ethyl vinyl ether, isobutyl vinyl ether, Ether compounds such as allyl glycidyl ether; halogen-containing vinyl compounds such as allyl chloride; other vinyl compounds such as allyl acetate, allyl alcohol, glycidyl methacrylate, and acrylamide; In the diene compound, non-conjugated dienes such as 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 2-methyl-1,4-pentadiene, 2,5-dimethyl-1,5-hexadiene, etc. Compounds; conjugated diene compounds such as 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene; It is done. These molecular weight regulators may be used alone or in combination of two or more.

  The molecular weight distribution of the alicyclic olefin polymer having a functional group used in the present invention is not particularly limited, but is a weight average molecular weight measured by gel permeation chromatography (GPC) using cyclohexane or toluene as a solvent ( The ratio (Mw / Mn) of Mw) to the number average molecular weight (Mn) is usually 5 or less, preferably 4 or less, more preferably 3 or less. In the case of using an alicyclic olefin polymer having a functional group whose weight average molecular weight or molecular weight distribution cannot be measured by the above-described method, the melt viscosity and the degree of polymerization are such that a resin layer can be formed by an ordinary melt processing method. Can be used.

  Although the glass transition temperature (Tg) of the alicyclic olefin polymer which has a functional group used by this invention is not specifically limited, It is preferable that it is 120-300 degreeC. If the Tg is too low, sufficient electrical insulation cannot be maintained at a high temperature, and if the Tg is too high, the multilayer printed circuit board may be cracked to break the conductive circuit when subjected to a strong impact.

  The curable resin composition containing the alicyclic olefin polymer having a functional group used in the present invention is dissolved in an organic solvent to form a varnish as described later. It is preferable to apply the polymer material film (intermediate layer) to form the first outer layer and the second outer layer. Therefore, the alicyclic olefin polymer having a functional group used in the present invention is preferably one that dissolves in an organic solvent as described later at room temperature.

  The curing agent used in the present invention is not particularly limited as long as it forms a cross-linked structure on the alicyclic olefin polymer having a functional group by heating, and it is not limited to a general curable resin composition for forming an electric insulating film. Although the compounding hardening | curing agent can be used, the compound which has two or more functional groups which can react with the functional group of the alicyclic olefin polymer which has a functional group to be used, and can form a bond is used as a hardening | curing agent. It is preferable. For example, as an alicyclic olefin polymer having a carboxyl group or a carboxylic acid anhydride group as the alicyclic olefin polymer having a functional group, the curing agent preferably used includes a polyvalent epoxy compound, a polyvalent olefin polymer Examples include isocyanate compounds, polyvalent amine compounds, polyhydric hydrazide compounds, aziridine compounds, basic metal oxides, and organometallic halides. These may be used alone or in combination of two or more. May be. These compounds and peroxides may be used in combination as a curing agent.

  Examples of the polyvalent epoxy compound that can be used as a curing agent include a phenol novolac epoxy compound, a cresol novolac epoxy compound, a cresol epoxy compound, a bisphenol A epoxy compound, a bisphenol F epoxy compound, and a hydrogenated bisphenol A epoxy. Glycidyl ether type epoxy compounds such as compounds; polycyclic epoxy compounds such as alicyclic epoxy compounds, glycidyl ester type epoxy compounds, glycidyl amine type epoxy compounds, isocyanurate type epoxy compounds, phosphorus-containing epoxy compounds; The compound which has the above epoxy groups is mentioned, These may be used individually by 1 type and may use 2 or more types together.

  As the polyvalent isocyanate compound that can be used as a curing agent, diisocyanates and triisocyanates having 6 to 24 carbon atoms are preferable. Examples of diisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, p-phenylene diisocyanate, etc. Is mentioned. Examples of triisocyanates include 1,3,6-hexamethylene triisocyanate, 1,6,11-undecane triisocyanate, bicycloheptane triisocyanate, etc., and these are used alone. It may also be used in combination of two or more.

  Examples of the polyvalent amine compound that can be used as a curing agent include aliphatic polyamine compounds having 4 to 30 carbon atoms having two or more amino groups, and aromatic polyamine compounds, such as guanidine compounds. Those having non-conjugated nitrogen-carbon double bonds are not included. Examples of the aliphatic polyvalent amine compound include hexamethylene diamine, N, N′-dicinnamylidene-1,6-hexane diamine, and the like. Examples of aromatic polyvalent amine compounds include 4,4′-methylenedianiline, m-phenylenediamine, 4,4′-diaminodiphenyl ether, 4 ′-(m-phenylenediisopropylidene) dianiline, 4,4 ′-( p-phenylenediisopropylidene) dianiline, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 1,3,5-benzenetriamine, and the like. These may be used alone. Or two or more of them may be used in combination.

  Examples of polyhydric hydrazide compounds that can be used as curing agents include isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthalenedicarboxylic acid dihydrazide, maleic acid dihydrazide, itaconic acid dihydrazide, trimellitic acid dihydrazide, 1,3,5 -Benzenetricarboxylic acid dihydrazide, pyromellitic acid dihydrazide, etc. are mentioned, These may be used individually by 1 type and may use 2 or more types together.

  Examples of aziridine compounds that can be used as the curing agent include tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, tris [1- (2-methyl) aziridinyl] phosphinoxide, hexa [1- (2-Methyl) aziridinyl] triphosphatriazine and the like may be mentioned, and these may be used alone or in combination of two or more.

  In the case of using an alicyclic olefin polymer having a carboxyl group or a carboxylic anhydride group as the alicyclic olefin polymer having a functional group, the reactivity with the functional group is moderate among the aforementioned curing agents. From the viewpoint of easy handling of the curable resin composition, polyvalent epoxy compounds are preferably used, and glycidyl ether type epoxy compounds and alicyclic polyvalent epoxy compounds are particularly preferably used.

  The amount of the curing agent used in the curable resin composition is usually 1 to 100 parts by weight, preferably 5 to 80 parts by weight, more preferably 10 to 100 parts by weight of the alicyclic olefin polymer having a functional group. The range is 50 parts by weight. By using a hardening | curing agent with the usage-amount of such a range, the mechanical strength and electrical property of the hardened | cured material obtained by hardening | curing curable resin composition will become favorable.

  In order to accelerate the curing of the curable resin composition, the curable resin composition may contain a curing accelerator or a curing aid. As the curing accelerator, a curing accelerator blended in a general curable resin composition for forming an electrical insulating film may be used. When a polyvalent epoxy compound is used as the curing agent, a tertiary amine type is used. A compound, a boron trifluoride complex compound, or the like is preferably used as the curing accelerator. Among these, when a tertiary amine compound is used, the ease of lamination, insulation resistance, heat resistance, and chemical resistance of the resulting multilayer printed circuit board film are improved.

  Specific examples of the tertiary amine compound include, for example, chain tertiary amine compounds such as benzyldimethylamine, triethanolamine, triethylamine, tributylamine, tribenzylamine, dimethylformamide; pyrazoles, pyridines, pyrazines , Pyrimidines, indazoles, quinolines, isoquinolines, imidazoles, triazoles and the like. Among these, imidazoles, particularly substituted imidazole compounds having a substituent are preferable.

  Specific examples of the substituted imidazole compound include, for example, 2-ethylimidazole, 2-ethyl-4-methylimidazole, bis-2-ethyl-4-methylimidazole, 1-methyl-2-ethylimidazole, 2-isopropylimidazole, Alkyl-substituted imidazole compounds such as 2,4-dimethylimidazole and 2-heptadecylimidazole; 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-ethylimidazole 1-benzyl-2-phenylimidazole, benzimidazole, 2-ethyl-4-methyl-1- (2′-cyanoethyl) imidazole, 2-ethyl-4-methyl-1- [2 ′-(3 ″, 5 "-Diaminotriazinyl) ethyl] imidazo Like imidazole compounds substituted with a hydrocarbon group containing a ring structure, such as an aryl group or an aralkyl group such as. Among these, imidazole having a substituent containing a ring structure is preferable from the viewpoint of compatibility with an alicyclic olefin polymer having a functional group, and 1-benzyl-2-phenylimidazole is particularly preferable.

  These curing accelerators can be used alone or in combination of two or more. The blending amount of the curing accelerator may be appropriately selected depending on the purpose of use, but is usually 0.001 to 30 parts by weight, preferably 0. 0 to 100 parts by weight of the alicyclic olefin polymer having a functional group. It is 01-10 weight part, More preferably, it is 0.03-5 weight part.

  As the curing aid, a curing aid blended in a general curable resin composition for forming an electric insulating film may be used. Specific examples thereof include quinone dioxime, benzoquinone dioxime, and p-nitrosophenol. Oxime / nitroso curing aids such as: N, Nm-phenylene bismaleimide and other maleimide curing aids; diallyl phthalate, triallyl cyanurate, triallyl isocyanurate and other allyl curing aids; ethylene glycol di Examples thereof include methacrylate-based curing aids such as methacrylate and trimethylolpropane trimethacrylate; vinyl-based curing aids such as vinyltoluene, ethylvinylbenzene, and divinylbenzene. These curing aids can be used alone or in combination of two or more, and the blending ratio thereof is usually 1 to 1000 parts by weight, preferably 10 to 500 parts per 100 parts by weight of the curing agent used. The range is parts by weight.

If necessary, the curable resin composition may contain a rubbery polymer and other thermoplastic resins (other than those described above). The rubbery polymer is a polymer having a glass transition temperature of room temperature (25 ° C.) or lower, and includes a normal rubbery polymer and a thermoplastic elastomer. By adding a rubbery polymer or a thermoplastic resin to the curable resin composition, the flexibility of the resulting multilayer printed circuit board film can be improved. The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the rubbery polymer to be used may be appropriately selected, but is usually 5 to 200. Specific examples of rubber-like polymers include ethylene-α-olefin rubber-like polymers; ethylene-α-olefin-polyene copolymer rubbers; ethylene and unsaturated carboxylic acids such as ethylene-methyl methacrylate and etherene-butyl acrylate. Copolymers with esters; copolymers of ethylene and fatty acid vinyl such as ethylene-vinyl acetate; alkyl acrylates such as ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate Polybutadiene, polyisoprene, styrene-butadiene or styrene-isoprene random copolymer, acrylonitrile-butadiene copolymer, butadiene-isoprene copolymer, butadiene- (meth) acrylic acid alkyl ester copolymer, pig Diene rubber such as diene- (meth) acrylic acid alkyl ester-acrylonitrile copolymer, butadiene- (meth) acrylic acid alkyl ester-acrylonitrile-styrene copolymer; modified diene rubber such as epoxidized polybutadiene; butylene-isoprene A copolymer etc. are mentioned. Specific examples of the thermoplastic elastomer include aromatic vinyl such as styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, styrene-isoprene block copolymer, hydrogenated styrene-isoprene block copolymer, etc. Examples thereof include a conjugated diene block copolymer, a low crystalline polybutadiene resin, an ethylene-propylene elastomer, a styrene-grafted ethylene-propylene elastomer, a thermoplastic polyester elastomer, and an ethylene ionomer resin. Of these thermoplastic elastomers, hydrogenated styrene-butadiene block copolymers, hydrogenated styrene-isoprene block copolymers, and the like are preferable. Specifically, JP-A-2-133406 and JP-A-2 Examples described in JP-A-3-305814, JP-A-3-72512, JP-A-3-74409, and the like.

  Examples of other thermoplastic resins that can be blended in the curable resin composition include, for example, low density polyethylene, high density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene-ethyl acrylate copolymer, ethylene-acetic acid. Examples include vinyl copolymer, polystyrene, polyphenylene sulfide, polyphenylene ether, polyamide, polyester, polycarbonate, and cellulose triacetate.

  The rubber-like polymer and other thermoplastic resins can be used alone or in combination of two or more, and the blending amount is appropriately selected within a range not impairing the object of the present invention. In order not to impair the properties of the circuit board film as an insulating material, the blending amount is preferably 30 parts by weight or less with respect to 100 parts by weight of the alicyclic olefin polymer having a functional group.

  In the curable resin composition used in the present invention, for the purpose of further improving the flame retardancy of the multilayer printed circuit board film, for example, a general electrical insulating film such as a halogen flame retardant or a phosphate ester flame retardant You may mix | blend the flame retardant mix | blended with the curable resin composition for formation. However, it is preferable that the curable resin composition used in the present invention does not contain a flame retardant. The multilayer printed circuit board film of the present invention exhibits sufficient flame retardancy based on its configuration, so that sufficient flame retardancy can be ensured without blending a flame retardant into the curable resin composition. it can. Therefore, by using a curable resin composition that does not contain a flame retardant, it may be caused by halogen-based hazardous substance generation problems during the incineration processing of multilayer printed circuit board films that may be caused by the halogen-based flame retardant, and phosphate ester-based flame retardants. There can be obtained the advantage that there is no problem of deterioration of the environmental resistance of the multilayer printed circuit board film and deterioration of the adhesion between the layer of the curable resin composition and the conductive circuit. When the flame retardant is blended in the curable resin composition, the blending amount is preferably 30 parts by weight or less, more preferably 15 parts by weight or less with respect to 100 parts by weight of the alicyclic olefin polymer. .

  The curable resin composition used in the present invention may further include an inorganic filler, a flame retardant aid, a heat resistance stabilizer, a weather resistance stabilizer, an anti-aging agent, an ultraviolet absorber (laser processability improver) as necessary. Optional ingredients such as leveling agents, antistatic agents, slip agents, anti-blocking agents, anti-fogging agents, lubricants, dyes, natural oils, synthetic oils, waxes, emulsions, magnetic substances, dielectric property modifiers, toughening agents, etc. The What is necessary is just to select suitably the mixture ratio of an arbitrary component in the range which does not impair the objective of this invention.

  In obtaining the multilayer printed circuit board film of the present invention, the method of laminating the intermediate layer composed of the flame retardant organic polymer material film and the first outer layer and the second outer layer formed of the curable resin composition is particularly preferable. Although not limited, the curable resin composition is mixed with an organic solvent as a varnish, the varnish is applied to both sides of the flame retardant organic polymer material film, and the organic solvent is volatilized by drying it. A method of obtaining one outer layer and a second outer layer is preferred.

  The organic solvent used when the curable resin composition is used as a varnish has a boiling point of preferably 30 to 250 ° C., more preferably 50 to 200 ° C. for convenience of later heating and volatilization. Examples of such organic solvents include aromatic hydrocarbons such as toluene, xylene, ethylbenzene and trimethylbenzene; aliphatic hydrocarbons such as n-pentane, n-hexane and n-heptane; alicyclics such as cyclopentane and cyclohexane Hydrocarbons; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, and trichlorobenzene; ether compounds such as anisole; methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone.

  There is no particular limitation on the preparation method of the varnish, and for example, each component constituting the curable resin composition and the organic solvent may be mixed according to a conventional method. For example, a magnetic stirrer, high-speed homogenizer, dispersion, planetary stirrer They can be mixed using a twin-screw stirrer, a ball mill, a triple roll or the like. The mixing temperature is preferably not higher than the temperature at which the reaction between the alicyclic olefin polymer having a functional group and the curing agent occurs and not higher than the boiling point of the organic solvent. The amount of the organic solvent used is appropriately selected according to the intended thickness of the first outer layer and the second outer layer and the surface flatness of the first outer layer and the second outer layer, but the solid content concentration of the varnish is usually 5 It is the range which becomes -70 weight%, Preferably it is 10-65 weight%, More preferably, it is 20-60 weight%.

  The method of applying the varnish of the curable resin composition to the flame retardant organic polymer material film may be in accordance with conventional methods, for example, dip coating, bar coating, roll coating, curtain coating, die coating, slit coating, doctor Examples thereof include a blade method. Since the varnish of the curable resin composition to be applied is one in which the organic solvent is volatilized to form the first outer layer and the second outer layer of the multilayer printed circuit board film, the first after the organic solvent is volatilized. What is necessary is just to apply | coat the varnish of a curable resin composition, setting a coating film thickness so that the thickness of 1 outer layer and 2nd outer layer may become the below-mentioned.

  The drying conditions for volatilizing the organic solvent from the varnish of the curable resin composition applied to the flame retardant organic polymer material film are appropriately selected depending on the type of the organic solvent. The heating temperature is usually 20 to 300 ° C., preferably 30 to 200 ° C., and the heating time is usually 30 seconds to 1 hour, preferably 1 minute to 30 minutes. Thus, by volatilizing the organic solvent from the varnish of the curable resin composition, the first outer layer and the second outer layer formed of the curable resin composition can be formed.

The multilayer printed circuit board film of the present invention is a multilayer printed circuit board film comprising the intermediate layer obtained as described above, and a first outer layer and a second outer layer laminated on both sides of the intermediate layer. The thickness (t _M ) of the intermediate layer is 3 to 24 μm, the thickness (t _O1 ) of the first outer layer is 1 to 20 μm, and the thickness (t _O2 ) of the second outer layer is 6 to 20 μm. The ratio of the sum of the thicknesses of the first outer layer and the second outer layer to the thickness of the intermediate layer ((t _O1 + t _O2 ) / t _M ) is 0.5 to 3. Since the thickness of each layer of the multilayer printed circuit board film has such a relationship, the multilayer printed circuit board film exhibits excellent flame retardancy, and also has excellent electrical characteristics and wiring embedding properties. It will be a thing.

The thickness (t _M ) of the intermediate layer composed of the flame-retardant organic polymer material film in the multilayer printed circuit board film of the present invention is 3 to 24 μm, preferably 5 to 20 μm, more preferably 7 to 15 μm. If the intermediate layer is too thin, the flame retardancy of the multilayer printed circuit board film as a whole may be insufficient. If it is too thick, the multilayer printed circuit board film will easily absorb water, and the electrical properties will be poor. There is a risk of becoming something.

The thickness (t _O1 ) of the first outer layer made of the curable resin composition in the multilayer printed circuit board film of the present invention is 1 to 20 μm, preferably 5 to 20 μm, more preferably 7 to 15 μm. is there. When the first outer layer is not present or is too thin, a conductive circuit is directly formed on the intermediate layer made of a flame-retardant organic polymer material film to obtain a multilayer printed circuit board. There is a risk that the adhesion between and the conductive circuit will be insufficient. Moreover, when the first outer layer is too thick, the flame retardancy of the multilayer printed circuit board film may be insufficient.

The thickness (t _O2 ) of the second outer layer made of the curable resin composition in the multilayer printed circuit board film of the present invention is 6 to 20 μm, preferably 7 to 18 μm, more preferably 8 to 15 μm. is there. When the second outer layer is not present or when the second outer layer is too thin, the wiring embedding by the film (second outer layer) may be inferior when the multilayer printed circuit board film is laminated on the conductor circuit. Moreover, if the second outer layer is too thick, the flame retardancy of the multilayer printed circuit board film may be insufficient.

In the multilayer printed circuit board film of the present invention, the relationship between the thickness of the first outer layer (t _O1 ) and the thickness of the second outer layer (t _O2 ) is as long as the thickness of each layer is in the above-mentioned range. Although not particularly limited, when a method of applying varnish to a flame retardant organic polymer material film at the same time on both sides of the film such as dip coating is adopted, the productivity of the multilayer printed circuit board film is good Therefore, it is preferable that the thickness of the first outer layer and the thickness of the second outer layer are substantially equal. In this case, the thickness (t _O1 ) of the first outer layer and the thickness (t _O2 ) of the second outer layer are 6 to 20 μm, preferably 7 to 15 μm, and more preferably 8 to 12 μm.

In the multilayer printed circuit board film of the present invention, the ratio ((t _O1 + t _O2 ) / t _M ) between the sum of the thicknesses of the first outer layer and the second outer layer and the thickness of the intermediate layer is 0.5-3. Yes, preferably 0.8 to 2.9, more preferably 1.0 to 2.8. If this ratio ((t _O1 + t _O2 ) / t _M ) is too small, the electrical properties of the resulting multilayer printed circuit board film may be insufficient. If it is too large, the multilayer printed circuit board film Flame retardancy may be insufficient.

The thickness (t _O1 + t _M + t _O2 ) of the multilayer printed circuit board film of the present invention is not particularly limited, but is usually 10 to 64 μm, preferably 12 to 50 μm, more preferably 15 to 35 μm. . If the multilayer printed circuit board film is too thin as a whole, the insulating property of the electrical insulating film formed by the multilayer printed circuit board film may be insufficient, and if it is too thick, the resulting multilayer printed circuit board will be too thick. There is a risk that it may be difficult to accommodate in electronic equipment.

  The multilayer printed circuit board film of the present invention is provided with the multilayer printed circuit board film of the present invention on a support in order to facilitate the handling of the multilayer printed circuit board using the film. It is good also as a composition. Although a support body is not specifically limited, A resin film and metal foil are used suitably. The resin film that can be used as the support is usually a thermoplastic resin film, specifically, a polyethylene terephthalate film, a polypropylene film, a polyethylene film, a polycarbonate film, a polyethylene naphthalate film, a polyarylate film, and a nylon film; Etc. Among these resin films, a polyethylene terephthalate film and a polyethylene naphthalate film are preferable from the viewpoints of heat resistance, chemical resistance, peelability after lamination, and the like. Examples of the metal foil that can be used as the support include copper foil, aluminum foil, nickel foil, chrome foil, gold foil, and silver foil. From the viewpoint of good conductivity, a copper foil, particularly an electrolytic copper foil or a rolled copper foil is preferred. The thickness of the support is not particularly limited, but is usually 1 μm to 200 μm, preferably 2 μm to 150 μm, more preferably 3 to 100 μm from the viewpoint of workability and the like. The support may be provided on the first outer layer side or the second outer layer side of the multilayer printed circuit board film, but is preferably provided on the first outer layer side.

  The film for multilayer printed circuit boards of the present invention is used for forming an electrical insulating film of a multilayer printed circuit board. The method of constructing a multilayer printed circuit board using the multilayer printed circuit board film of the present invention is not particularly limited. For example, the conductive circuit is formed by the same method as in the case of using a conventional multilayer printed circuit board film. After laminating the substrate on the surface and the multilayer printed circuit board film, the layers (first outer layer and second outer layer) formed of the curable resin composition of the multilayer printed circuit board film are cured, and further multilayer printing is performed. A conductive circuit may be formed on the surface of the circuit board film.

  Among the multilayer printed circuit boards obtained by using the multilayer printed circuit board film of the present invention, the multilayer printed circuit board of the present invention, which is particularly preferable, has a conductive circuit having a thickness of 5 to 10 μm on the surface. The multilayer printed circuit board film of the present invention is laminated on a substrate having the multilayer printed circuit board so that the surface having the conductive circuit of the substrate and the second outer layer of the multilayer printed circuit board film are in contact with each other. The first outer layer and the second outer layer of the film for use are cured, and a conductive circuit is formed on the first outer layer of the film for a multilayer printed circuit board.

  Further, the method for producing a multilayer printed circuit board of the present invention, which is particularly preferable as a method for producing a multilayer printed circuit board using the multilayer printed circuit board film of the present invention, has a thickness of 5 to 10 μm. Laminating a multilayer printed circuit board film of the present invention on a substrate having a conductive circuit on its surface so that the surface having the conductive circuit of the substrate is in contact with the second outer layer of the multilayer printed circuit board film; The method includes a step of curing the first outer layer and the second outer layer of the printed circuit board film, and a step of forming a conductive circuit on the first outer layer of the multilayer printed circuit board film.

  The substrate used for forming the multilayer printed circuit board by laminating with the multilayer printed circuit board film of the present invention is not particularly limited. For example, a substrate obtained by forming a desired circuit on a commercially available copper-clad substrate As described later, a multilayer printed circuit board film itself having a conductive circuit formed thereon can be used as a substrate. However, when the multilayer printed circuit board film of the present invention is laminated with a substrate having a conductive circuit having a thickness of 5 to 10 μm on the surface, the conductive circuit of the substrate is a layer of the curable resin composition of the film. Since it can be embedded particularly well in the (second outer layer), it is preferably used in combination with such a substrate.

  The method for laminating the multilayer printed circuit board film of the present invention and the substrate having the conductive circuit on the surface is not particularly limited, but the surface of the substrate having the conductive circuit and the second outer layer of the multilayer printed circuit board film Are laminated so that they are in contact with each other, and are heated and pressure-bonded (lamination) using a pressure machine such as a pressure laminator, press, vacuum laminator, vacuum press, roll laminator, etc., so that the conductive circuit of the substrate and the second outer layer of the film And a method of bonding so that there is substantially no void at the interface. The thermocompression bonding is preferably performed under vacuum in order to improve the embedding property of the wiring and suppress the generation of bubbles. The temperature of the thermocompression bonding operation is usually 30 to 250 ° C., preferably 70 to 200 ° C., the applied pressure is usually 10 kPa to 20 MPa, preferably 100 kPa to 10 MPa, and the time is usually 30 seconds to 5 hours, preferably Is 1 minute to 3 hours. The atmospheric pressure is usually 100 kPa to 1 Pa, preferably 40 kPa to 10 Pa under reduced pressure.

  In addition, when laminating a film for a multilayer printed circuit board and a substrate having a conductive circuit on its surface, pretreatment for roughening the surface of the conductive circuit on the substrate in advance in order to improve the adhesion between them. It is preferable to apply. As a pretreatment method, a known technique is not particularly limited and can be used. For example, if the conductive circuit of the substrate is made of copper, an oxidation treatment in which a strong alkaline oxidizing solution is brought into contact with the surface of the conductive circuit to form a tufted copper oxide layer on the surface to roughen the surface. Method, method of oxidizing conductive circuit surface with sodium borohydride, formalin, etc. after oxidation by the previous method, method of depositing and roughening plating on conductive circuit, contacting organic circuit with conductive circuit Examples include a method in which copper grain boundaries are eluted and roughened, and a method in which a primer layer is formed on a conductive circuit with a thiol compound or a silane compound. Among these, from the viewpoint of easy maintenance of the shape of a fine circuit pattern, a method in which an organic acid is brought into contact with a conductive circuit to elute and roughen the grain boundaries of copper, and a thiol compound or a silane compound are used. A method of forming a primer layer is preferred.

  The method of curing the first outer layer and the second outer layer of the multilayer printed circuit board film after laminating the multilayer printed circuit board film and the substrate is not particularly limited, but the substrate on which the multilayer printed circuit board film is laminated The method of heating the whole is mentioned. The heating conditions for curing the first outer layer and the second outer layer are appropriately selected depending on the type of curing agent contained in the curable resin composition, but the heating temperature is usually 30 to 400 ° C., preferably Is 70 to 300 ° C., more preferably 100 to 200 ° C., and the heating time is 0.1 to 5 hours, preferably 0.5 to 3 hours. The heating means is not particularly limited, and for example, an electric oven can be used. By curing the first outer layer and the second outer layer in this manner, the multilayer printed circuit board film of the present invention integrally forms the electrical insulating film of the multilayer printed circuit board.

  After the first outer layer and the second outer layer of the multilayer printed circuit board are cured, a conductive circuit is formed on the cured layer (on the first outer layer). Usually, however, before the conductive circuit is formed. And a conductive substrate formed on the substrate and an electrically insulating film (film for a multilayer printed circuit board), and a laminated substrate and an electrically insulating film used for electrically connecting the conductive circuit formed on the substrate. A via hole penetrating through is provided. This via hole can be formed by chemical processing such as photolithography or physical processing such as drilling, laser, or plasma etching. Among these methods, a laser method (a carbon dioxide laser, an excimer laser, a UV-YAG laser, or the like) is preferable because a fine via hole can be formed without degrading the characteristics of the electrical insulating film.

  In addition, before forming the conductive circuit on the electric insulating film (the first outer layer of the multilayer printed circuit board film), in order to improve the adhesion between the electric insulating film and the formed conductive circuit, electric insulation It is preferable to roughen the surface of the film. The method of the roughening treatment is not particularly limited, and examples thereof include a method of roughening by oxidizing using an oxidizing compound such as permanganate.

  After laminating the multilayer printed circuit board film and the substrate and curing the first outer layer and the second outer layer of the multilayer printed circuit board film, after providing via holes or performing oxidation treatment as necessary Forms a conductive circuit on the electrical insulating film (the first outer layer of the multilayer printed circuit board film). The material for the conductive circuit is not particularly limited as long as it is a conductive material, and a material generally used as a material for the conductive circuit can be used. Suitable materials include metal materials such as copper, silver, gold, nickel, aluminum, and tungsten, and copper is particularly preferably used.

The method for forming the conductive circuit on the electrical insulating film (the first outer layer of the multilayer printed circuit board film) is not particularly limited, and a generally used method can be employed. In order to form a conductive circuit, as a method for forming a layer of a conductive material over an electrical insulating film, a so-called dry film formation method or a wet film formation method can be used. Specific examples of the dry deposition method include vacuum deposition (normal vacuum deposition, flash deposition, gas scattering deposition, electric field deposition, reactive deposition, etc.), ion plating deposition (DC ion plating, high-frequency ion plating, ion Physical vapor deposition methods such as beam evaporation, HCD method, arc discharge ion plating), sputtering (DC sputtering, high frequency sputtering, magnetron sputtering, ion beam sputtering, etc.), thermal CVD (thermal CVD, MOCVD, etc.), plasma CVD, etc. (DC plasma CVD, high frequency CVD, microwave plasma CVD, etc.), photo CVD (excimer laser excitation, mercury lamp excitation, CO ₂ laser excitation, etc.), plasma polymerization (DC discharge excitation, microwave excitation, high frequency excitation, etc.), etc. Chemical vapor deposition Law. Specific examples of the wet film forming method include an electrolytic plating method and an electroless plating method. Among these methods, it is preferable to form a layer of a conductive material by an electroless plating method from the viewpoint that a stable and highly adhesive layer can be obtained, and also formed by an electroless plating method. It is also preferred to apply an electroplating method on the layer of conductive material to grow the layer of conductive material. When a via hole is provided, a conductive material layer is usually formed also on the inner wall surface.

  When the electroless plating method is adopted, usually, silver, palladium, zinc, cobalt, gold, platinum, iridium, ruthenium, which acts as a reduction catalyst on the electrical insulating film (the first outer layer of the multilayer printed circuit board film) Adsorb catalyst nuclei such as osmium. Further, as the electroless plating solution used in the electroless plating method, for example, a known autocatalytic electroless plating solution may be used. The metal species, reducing agent species, complexing agent species, hydrogen contained in the plating solution may be used. What is necessary is just to select an ion concentration, a dissolved oxygen concentration, etc. suitably. Examples of electroless plating solutions include electroless copper plating solutions containing ammonium hypophosphite or hypophosphorous acid, ammonium borohydride, hydrazine, formalin, etc. as reducing agents, and sodium hypophosphite as reducing agents. Electroless nickel-phosphorous plating solution, electroless nickel-boron plating solution using dimethylamine borane as reducing agent, electroless palladium plating solution, electroless palladium-phosphorous plating solution using sodium hypophosphite as reducing agent, electroless Examples thereof include a gold plating solution, an electroless silver plating solution, and an electroless nickel-cobalt-phosphorus plating solution using sodium hypophosphite as a reducing agent. In addition, it is preferable to perform the rust prevention process of making the layer of the electroconductive material formed by the electroless-plating method contact a rust preventive agent.

  Moreover, as an electroplating solution used in the case of growing a conductive material layer by applying an electroplating method on a conductive material layer formed by an electroless plating method, a known electroplating solution may be used. For example, a copper sulfate plating solution, a copper pyrophosphate plating solution, an electrolytic nickel plating solution, or the like can be used. In addition, the electrolytic plating solution may contain additives such as a complexing agent, a brightening agent, a stabilizer, and a buffering agent as necessary.

  A method for forming a conductive circuit using a conductive material is to form a layer of a conductive material over the entire surface where the conductive circuit is to be formed, and then remove the unnecessary conductive material to form a circuit pattern. The method (subtractive method) and the method of forming a layer of a conductive material so as to have a circuit pattern (additive method) can be broadly classified, and any method can be adopted in the present invention.

  As an example of applying the subtractive method, a conductive material layer is formed on the entire surface of the electrical insulating film (first outer layer of the multilayer printed circuit board film) by the above-described method, and then the conductive material An example is a method in which an etching resist solution is applied to a portion of a layer to be left as a circuit pattern to form a resist film, and then an unnecessary conductive material is removed by immersion in the etching solution, and then the resist film is peeled off. . In addition, as an example of applying the additive method, a resist solution is applied to a portion where a conductive material is not necessary for forming a circuit pattern of an electrical insulating film (first outer layer of a multilayer printed circuit board film). There is a method in which a film is formed, and then a layer of a conductive material is formed on the electrical insulating film partially formed with a resist film by the above-described method, and then the resist film is peeled off.

  After forming the conductive circuit on the electrical insulating film (first outer layer of the multilayer printed circuit board film), it is preferable to perform an annealing treatment from the viewpoint of improving the adhesion between the electrical insulating film and the conductive circuit. . The method of annealing treatment is not particularly limited, and examples thereof include a method of heating the electrical insulating film together with the substrate in an oven, and a method of heating while pressing the electrical insulating film and the substrate using a press plate or a heating roll. . The heating temperature and heating time in the annealing treatment are not particularly limited, but the heating temperature is usually 50 to 350 ° C., preferably 80 to 250 ° C., and the heating time is usually 0.1 to 10 hours, preferably 0. 1 to 5 hours.

  The multilayer printed circuit board obtained by using the multilayer printed circuit board film of the present invention may be obtained by laminating the multilayer printed circuit board film of the present invention only on one side of the board, or on both sides of the board. It may be a laminate of the multilayer printed circuit board film of the invention. Further, a multilayer printed circuit board film may be further laminated on an electric insulating film made of a multilayer printed circuit board film laminated on a substrate and having a conductive circuit formed thereon.

  The multilayer printed circuit board thus obtained exhibits excellent flame retardancy even when a curable resin composition containing no chlorine or bromine atom-containing polymer or flame retardant is used. In addition, because it is made of the multilayer printed circuit board film of the present invention, which has excellent electrical characteristics and wiring embedding properties, it exhibits excellent flame retardancy, and further, in terms of signal propagation speed and insulation reliability. Is also excellent.

  The use of the multilayer printed circuit board obtained using the multilayer printed circuit board film of the present invention is not particularly limited. For example, in electronic devices such as computers and mobile phones, semiconductor elements such as CPUs and memories, and other mounting parts It can be suitably used as a substrate for use.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In addition, unless otherwise indicated, the part and% in each example are a basis of weight.

Various physical properties were evaluated according to the following methods.
(1) Number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymer: measured by gel permeation chromatography (GPC) using toluene or tetrahydrofuran as a developing solvent, It calculated | required as a polystyrene conversion value.
(2) Hydrogenation rate of polymer: The hydrogenation rate means the ratio of the number of moles of unsaturated bonds hydrogenated to the number of moles of unsaturated bonds in the polymer before hydrogenation, and a ¹ H-NMR spectrum. Obtained by measurement.
(3) Carboxylic anhydride group content of polymer: The ratio of the number of moles of carboxylic anhydride groups to the total number of monomer units in the polymer, and was determined by ¹ H-NMR spectrum measurement.
(4) Glass transition temperature (Tg) of polymer: Measured by a differential scanning calorimetry method (DSC method) at a heating rate of 10 ° C./min.
(5) Thickness of each layer constituting the film: After cutting the multilayer printed circuit board film before curing the layer formed of the curable resin composition, and polishing the cross section, the cross section is subjected to an optical microscope. Measured by observation.
(6) Flame retardancy: After laminating a multilayer printed circuit board film with a support on both sides of a halogen-free board having a thickness of 0.6 mm, a length of 11 cm, and a width of 16 cm obtained by etching copper on both sides, only the support is attached. The layer was peeled off and heated at 60 ° C. for 30 minutes, then at 160 ° C. for 30 minutes, and further at 170 ° C. for 60 minutes to cure the layer formed of the curable resin composition. This was cut into strips having a width of 13 mm and a length of 100 mm to prepare a flame-retardant evaluation substrate. About this flame-retardant evaluation board | substrate, it measured according to UL94V vertical flame-retardant test method. The evaluation criteria are as follows.
○: UL94 V-1 or more ×: Less than UL94 V-1 (7) Adhesiveness of conductive circuit: A laminate in which a copper film is formed by electroless plating is added to an aqueous solution of 100 g / liter sulfuric acid at 25 ° C. The rust preventive agent was removed by immersion for a minute, and an electrolytic copper plating film was formed on the copper film to form a 12 μm thick electrolytic copper plating film, followed by annealing at 170 ° C. for 60 minutes. For the obtained sample, the peel strength between the electrical insulating film (cured curable resin composition layer) and the copper layer before forming the circuit pattern was measured according to JIS C6481-1996, and the result Based on the following criteria.
○: Average peel strength is 8 N / cm or more
Δ: The average peel strength is 5 N / cm or more and less than 8 N / cm ×: The average peel strength is less than 5 N / cm (8) Wiring embedding property: After cutting the sample and polishing its cross section, The cross section was observed with an optical microscope. The evaluation criteria are as follows.
○: No embedding defect x: Embedding defect present (9) Water absorption: Rolled copper with a thickness of 75 μm so that the multilayer printed circuit board film with support is in contact with the multilayer printed circuit board film and the rolled copper foil Laminated on one side of the foil. Next, after peeling off the support from the multilayer printed circuit board film of the laminate, the laminate is heated at 160 ° C. for 30 minutes and further heated at 170 ° C. for 60 minutes to cure the multilayer printed circuit board film. The layer formed with the conductive resin composition was cured. And by immersing this laminated body in a cupric chloride / hydrochloric acid mixed solution, the rolled copper foil was completely removed from the laminated body, and the film in which the layer formed with the curable resin composition was cured was obtained. . The water absorption of this film was measured according to JIS K 6911, and based on the results, the following criteria were used.
○: Water absorption rate is less than 0.5% Δ: Water absorption rate is 0.5% or more and less than 1.0% ×: Water absorption rate is 1.0% or more (10) Environmental resistance: Environmental test conducted by JPCA-ET08-2007 It was performed according to the following criteria based on the results.
○: Insulation resistance value is 10 ⁷ Ω or more ×: Insulation resistance value is less than 10 ⁷ Ω (11) Electrical characteristics: A layer formed of the curable resin composition obtained in the same manner as in the above (9) is cured. A test piece having a width of 2.0 mm and a length of 50 mm was cut out from the obtained film, and the relative dielectric constant and dielectric loss tangent at 10 GHz were measured using a cavity resonator perturbation method dielectric constant measuring apparatus, and judged according to the following criteria.
○: Dielectric tangent is less than 0.01 and relative dielectric constant is less than 2.8 Δ: Dielectric tangent is less than 0.01 and relative dielectric constant is 2.8 or more ×: Dielectric tangent is 0.01 or more thing

[Synthesis Example 1]
8-ethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene 70 parts, bicyclo [2.2.1] hept-2-ene-5,6-dicarboxylic anhydride 30 parts, 1-hexene 1.1 parts, xylene 300 parts and A ruthenium-based polymerization catalyst (C1063, manufactured by Wako Pure Chemical Industries, Ltd.) (0.009 parts) was charged into a nitrogen-substituted pressure-resistant glass reactor and subjected to a polymerization reaction at 80 ° C. for 2 hours with stirring to obtain a solution of a ring-opening metathesis polymer. Got. When this solution was measured by gas chromatography, it was confirmed that substantially no monomer remained, and the polymerization conversion rate was 99.9% or more. Next, 100 parts of the obtained ring-opening metathesis polymer solution was charged into a nitrogen-substituted autoclave and stirred at 150 ° C. and a hydrogen pressure of 7 MPa for 5 hours to carry out a hydrogenation reaction. A solution of coalescence (1) was obtained. The resulting alicyclic olefin polymer (1) had a weight average molecular weight of 63,000, a number average molecular weight of 28,000, and a molecular weight distribution of 2.3. The hydrogenation rate was 99.9%, and the carboxylic acid anhydride group content was 30 mol%. The solid content concentration of the alicyclic olefin polymer (1) solution was 25%.

[Synthesis Example 2]
7,10-methano-6b, 7,10,10a-tetrahydrofluoranthene 70 parts, bicyclo [2.2.1] hept-2-ene-5,6-dicarboxylic anhydride 30 parts, 1-hexene 1 .1 part, 300 parts of anisole and 0.009 part of ruthenium-based polymerization catalyst (C1063, manufactured by Wako Pure Chemical Industries, Ltd.) were charged into a pressure-resistant glass reactor substituted with nitrogen, and the polymerization reaction was carried out at 80 ° C. for 2 hours with stirring. A solution of ring-opening metathesis polymer was obtained. When this solution was measured by gas chromatography, it was confirmed that substantially no monomer remained, and the polymerization conversion rate was 99.9% or more. Next, 100 parts of the obtained ring-opening metathesis polymer solution was charged into a nitrogen-substituted autoclave and stirred at 150 ° C. and a hydrogen pressure of 7 MPa for 5 hours to carry out a hydrogenation reaction. A solution of coalescence (2) was obtained. The resulting alicyclic olefin polymer (2) had a weight average molecular weight of 50,000, a number average molecular weight of 26,000, and a molecular weight distribution of 1.9. The hydrogenation rate was 99.9%, and the carboxylic acid anhydride group content was 30 mol%. The solid content concentration of the alicyclic olefin polymer (2) solution was 25%.

[Example 1]
400 parts of the solution of the alicyclic olefin polymer (1) obtained in Synthesis Example 1 (100 parts as the amount of the alicyclic olefin polymer (1)), hydrogenated bisphenol A diglycidyl ether (trade name YX8000) as the curing agent 36 parts, manufactured by Japan Epoxy Resin Co., Ltd., 1 part of 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol as an ultraviolet absorber, an anti-aging agent 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6-trione, 1-benzyl as a curing accelerator As a component for improving flexibility, 0.5 part of 2-phenylimidazole and 10 parts of liquid polybutadiene (trade name Ricon 152, manufactured by Sartomer Japan) were fixed. So that the partial concentration of 28% to obtain a varnish of a curable resin composition by mixing xylene using a planetary stirrer. Polyimide having a size of 250 mm x 250 mm and a thickness of 8 µm on a polyethylene naphthalate film (support) having a size of 300 mm x 300 mm and a thickness of 100 µm and an average surface roughness Ra of 0.08 µm A film (trade name Upilex: manufactured by Ube Industries, Ltd., VTM-0 in a test conforming to UL94 standard) was installed, and then the varnish obtained above was polyimide film using a YD type doctor blade (gap size 130 μm) Coated. Next, the polyimide film coated with the varnish was dried at 80 ° C. for 5 minutes in a nitrogen atmosphere, thereby forming a layer of a curable resin composition serving as the first outer layer of the multilayer printed circuit board film. By removing the support from the laminate of the obtained polyimide film and the curable resin composition layer, applying a varnish by the same method on the opposite side to the previous coating surface of the polyimide film, and drying, a multilayer A layer of a curable resin composition to be the second outer layer of the printed circuit board film was formed to obtain a multilayer printed circuit board film of Example 1 with a support. The thicknesses of the first outer layer and the second outer layer of this multilayer printed circuit board film were each 10 μm. Moreover, flame retardance, water absorption, and electrical characteristics were evaluated using this multilayer printed circuit board film. The results are shown in Table 1.

  On the other hand, on the surface of the core material obtained by impregnating glass fiber with a varnish containing a glass filler and a halogen-free epoxy resin, copper having a thickness of 18 μm was stuck, thickness 0.8 mm, length 150 mm × The surface of a double-sided copper-clad substrate with a width of 150 mm is microetched using an organic acid to form a conductive circuit with a wiring width and distance between wirings of 10 μm and a thickness of 10 μm. A substrate having

  The two multilayer printed circuit board films of Example 1 were cut together with the support into a size of 150 mm length × 150 mm width, and these films were placed on both sides of the substrate so that the second outer layer of the film and the substrate were in direct contact with each other. Superimposed. This was depressurized to 200 Pa using a vacuum laminator provided with heat-resistant rubber press plates at the top and bottom, and heat-pressed for 120 seconds at a temperature of 120 ° C. and a pressure of 1.0 MPa (primary press). Furthermore, using a vacuum laminator provided with heat-resistant rubber press plates covered with metal press plates at the top and bottom, the pressure was reduced to 200 Pa and thermocompression bonded at a temperature of 120 ° C. and 1.0 MPa for 300 seconds (secondary press ). Subsequently, the support was peeled off to obtain a laminate of the multilayer printed circuit board film and the substrate.

  This laminate was immersed in a 1.0% aqueous solution of 1- (2-aminoethyl) -2-methylimidazole at 30 ° C. for 10 minutes, then immersed in water at 25 ° C. for 1 minute, and then with an air knife. Excess solution was removed. This was left to stand at 160 ° C. for 30 minutes in a nitrogen atmosphere to cure the layer of the curable resin composition of the multilayer printed circuit board film. This laminate was rock-immersed for 10 minutes in an aqueous solution at 70 ° C. adjusted to have a permanganic acid concentration of 60 g / liter and a sodium hydroxide concentration of 28 g / liter. Next, this laminate was rock-immersed in a water tank for 1 minute, and further washed in water by immersion in another water tank for 1 minute. Subsequently, the laminate was immersed in an aqueous solution at 25 ° C. adjusted to have a hydroxylamine sulfate concentration of 170 g / liter and sulfuric acid of 80 g / liter for 5 minutes, neutralized and reduced, and then washed with water.

  Next, as a pretreatment for plating, the laminate after washing with water is 200 ml / liter of Alcup Activator MAT-1-A (manufactured by Uemura Kogyo) and 30 ml / liter of Alcup Activator MAT-1-B (manufactured by Uemura Kogyo). Then, it was immersed in a 60 ° C. Pd salt-containing plating catalyst aqueous solution adjusted so that sodium hydroxide was 0.35 g / liter for 5 minutes. Next, the laminate was immersed in a water tank for 1 minute and further immersed in another water tank for 1 minute to be washed with water, and then Alcup Reuters MAB-4-A (manufactured by Uemura Kogyo Co., Ltd.) was 20 ml / The plating catalyst was reduced by immersing it in a solution adjusted to 200 ml / liter of liter, Alcap Reducer MAB-4-B (manufactured by Uemura Kogyo Co., Ltd.) at 35 ° C. for 3 minutes. In this way, a plating catalyst was adsorbed to obtain a laminate subjected to pretreatment for plating.

  Then, the laminate subjected to the plating pretreatment is 100 ml / liter of Sulcup PSY-1A (manufactured by Uemura Kogyo), 40 ml / liter of Sulcup PSY-1B (manufactured by Uemura Kogyo), and 0.2 mol / liter of formalin. Electroless copper plating treatment was performed by dipping for 5 minutes at a temperature of 36 ° C. while air was blown into the aqueous solution prepared. The laminate is further immersed in a water tank for 1 minute and further immersed in another water tank for 1 minute, washed with water, dried, subjected to rust prevention treatment, and a copper film is formed by electroless plating. A laminated body was obtained. This laminated body was used for the test for evaluating adhesiveness with a conductive circuit. The results are shown in Table 1.

  Further, a commercially available photosensitive resist was spin-coated on the surface of the laminate obtained as described above (the first outer layer of the multilayer printed circuit board film), and the resist was thermally cured. Next, a mask having a predetermined pattern was brought into close contact with the resist layer and exposed, and then developed to obtain a resist pattern. Then, electrolytic copper plating is performed on the copper film on which the resist pattern is not formed to form an electrolytic copper plating film having a thickness of 12 μm, and then the resist pattern is stripped and removed with a stripping solution. The copper film formed on the electroless copper plating existing underneath was removed with a cupric chloride / hydrochloric acid mixed solution to form a conductive circuit pattern. Finally, the multilayer body was annealed at 170 ° C. for 30 minutes to obtain the multilayer printed circuit board of Example 1. The obtained multilayer printed circuit board was evaluated for wiring embedding property and environmental resistance. The results are shown in Table 1.

[Example 2]
Instead of 400 parts of the alicyclic olefin polymer (1) obtained in Synthesis Example 1, 400 parts of the alicyclic olefin polymer (2) obtained in Synthesis Example 2 (alicyclic olefin polymer (2 ) Was used, and the amount of hydrogenated bisphenol A diglycidyl ether used was changed to 44 parts, and epoxidized liquid polybutadiene (trade name Ricon 654, Sartomer in place of 10 parts of liquid polybutadiene) A film for a multilayer printed circuit board and a multilayer printed circuit board of Example 2 were obtained in the same manner as in Example 1 except that 10 parts (made by Japan) were used. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3
A multilayer printed circuit board of Example 3 in the same manner as in Example 1 except that a 9 μm thick aramid film (manufactured by Toray Industries, Inc., VTM-0 in a test conforming to UL94 standard) was used instead of the polyimide film. Films and multilayer printed circuit boards were obtained. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
Implemented in the same manner as in Example 1 except that a liquid crystal polymer film having a thickness of 12 μm (trade name Biac, manufactured by Japan Gore-Tex Co., Ltd., VTM-0 in a test based on UL94 standard) was used instead of the polyimide film. The film for multilayer printed circuit boards of Example 4 and the multilayer printed circuit board were obtained. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5
The same as in Example 1 except that the thickness of the polyimide film used was changed to 13 μm and the coating of the first outer layer of the multilayer printed circuit board film was performed with a bar coater (number: No. 22). Thus, a multilayer printed circuit board film and a multilayer printed circuit board of Example 5 were obtained. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6
The coating of the first outer layer of the multilayer printed circuit board film was performed with a bar coater (number: No. 22), and the coating of the second outer layer of the multilayer printed circuit board film was performed with a YD type doctor blade (gap A film for a multilayer printed circuit board and a multilayer printed circuit board of Example 6 were obtained in the same manner as in Example 1 except that the measurement was performed with a dimension of 180 μm. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7
Film for multilayer printed circuit board and multilayer printed circuit of Example 7 in the same manner as in Example 1 except that 10 parts of phosphate ester flame retardant (PX200, manufactured by Daihachi Kogyo Co., Ltd.) was further added to the varnish. A substrate was obtained. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
The thickness of the polyimide film used was changed to 25 μm, the first outer layer of the multilayer printed circuit board film was coated with a YD doctor blade (gap size 200 μm), and the multilayer printed circuit board film A multilayer printed circuit board film and a multilayer printed circuit board of Comparative Example 1 were obtained in the same manner as in Example 1 except that the coating of the second outer layer was performed with a bar coater (number: No. 10). These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
Example except that the thickness of the polyimide film used was changed to 25 μm, and the coating of the first outer layer and the second outer layer of the multilayer printed circuit board film was performed with a bar coater (number line: No. 22) In the same manner as in Example 1, a multilayer printed circuit board film and a multilayer printed circuit board of Comparative Example 2 were obtained. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 3]
The multilayer printed circuit board of Comparative Example 3 was the same as Example 1 except that the coating of the first outer layer and the second outer layer of the multilayer printed circuit board film was performed with a bar coater (numbered line: No. 20). Films and multilayer printed circuit boards were obtained. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 4]
A multilayer printed circuit board film and a multilayer printed circuit board of Comparative Example 4 were obtained in the same manner as in Example 1 except that the coating for forming the first outer layer was not performed on the polyimide film. These were evaluated in the same manner as in Example 1. The results are shown in Table 1.

As can be seen from Table 1, the multilayer printed circuit board using the multilayer printed circuit board film of the present invention exhibits excellent flame retardancy, and is excellent in electrical characteristics and wiring embeddability. It also has excellent adhesion with the conductive circuit provided. On the other hand, when the ratio ((t _O1 + t _O2 ) / t _M ) of the sum of the thicknesses of the first outer layer and the second outer layer of the multilayer printed circuit board film and the thickness of the intermediate layer is too large, the resulting multilayer The printed circuit board is inferior in flame retardancy (Comparative Example 1), and if this ratio is too small, the resulting multilayer printed circuit board is easy to absorb water, and the environmental resistance and electrical characteristics are also improved. It becomes inferior (Comparative Example 2). Furthermore, when the 2nd outer layer of the film for multilayer printed circuit boards is too thin, it is inferior to the embedding property of wiring (Comparative Examples 1-3). Also, when a multilayer printed circuit board film is not provided with a first outer layer, and a multilayer printed circuit board is obtained, a layer of conductive material (conductive circuit) is provided directly on the intermediate layer made of a flame retardant material. The peel strength of the conductive material layer was extremely small (Comparative Example 4).

Claims (5)

An intermediate layer composed of a flame retardant organic polymer material film that is V-0, V-1, VTM-0 or VTM-1 in a test based on the UL94 standard, and laminated on both sides of this intermediate layer, A film for a multilayer printed circuit board comprising a first outer layer and a second outer layer formed by a curable resin composition comprising an alicyclic olefin polymer having a curing agent and a curing agent,
The thickness (t _M ) of the intermediate layer is 3 to 24 μm, the thickness (t _O1 ) of the first outer layer is 1 to 20 μm, and the thickness (t _O2 ) of the second outer layer is 6 to 20 μm, A multilayer printed circuit board film, wherein a ratio ((t _O1 + t _O2 ) / t _M ) of the sum of the thicknesses of the first outer layer and the second outer layer to the thickness of the intermediate layer is 0.5 to 3 .   The multilayer printed circuit board film according to claim 1, wherein the alicyclic olefin polymer having a functional group does not contain a chlorine atom and a bromine atom.   The multilayer printed circuit board film according to claim 1, wherein the curable resin composition does not contain a flame retardant.   A multilayer printed circuit board film according to any one of claims 1 to 3, wherein the multilayer printed circuit board film according to any one of claims 1 to 3 is applied to a substrate having a conductive circuit having a thickness of 5 to 10 µm on the surface, and the multilayer printed circuit board. The film is laminated so as to be in contact with the second outer layer of the film for film, and further, the first outer layer and the second outer layer of the film for multilayer printed circuit board are cured, and conductive on the first outer layer of the film for multilayer printed circuit board. A multilayer printed circuit board having a structure obtained by forming a circuit.   A multilayer printed circuit board film according to any one of claims 1 to 3, wherein the multilayer printed circuit board film according to any one of claims 1 to 3 is applied to a substrate having a conductive circuit having a thickness of 5 to 10 µm on the surface, and the multilayer printed circuit board. A step of laminating the second outer layer of the film for contact, a step of curing the first outer layer and the second outer layer of the multilayer printed circuit board film, and a conductive circuit on the first outer layer of the multilayer printed circuit board film Forming a multilayer printed circuit board.