KR102480537B1 - Resin compositions, prepregs, metal clad laminates, printed wiring boards and flex-rigid printed wiring boards - Google Patents

Abstract

A resin composition capable of forming a prepreg having good moldability and high adhesion to a base material and less occurrence of powder fall-off and a cured product having a low coefficient of thermal expansion. The resin composition contains an epoxy resin, dicyandiamide, a phenoxy resin, a core shell rubber, and an inorganic filler. The weight average molecular weight of the phenoxy resin is 30000 or more. The tensile elongation of the phenoxy resin is 20% or more. The content of the phenoxy resin is 5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the epoxy resin. The content of the core-shell rubber is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the epoxy resin.

Description

Resin compositions, prepregs, metal clad laminates, printed wiring boards and flex-rigid printed wiring boards

The present disclosure relates to resin compositions, prepregs, metal clad laminates, printed wiring boards, and flex-rigid printed wiring boards.

Conventionally, the prepreg used for manufacture of a printed wiring board etc. is formed by impregnating a fiber base material with a resin composition containing a thermosetting resin, followed by heat drying until it becomes a semi-cured state. Then, after cutting this prepreg to a predetermined size, overlapping the required number of sheets, overlapping the metal foil on one side or both sides, heating and pressurizing this to laminate, forming a metal clad laminate used in the manufacture of a printed wiring board. A clad laminated board is produced there is.

However, since the prepreg is in a semi-cured state, it is brittle, and powder fall-off is likely to occur when the prepreg is cut or laminated. There is a possibility that the produced laminated sheet is dented like a dent due to powder fall-off occurring during handling of the prepreg, resulting in defective dent.

In order to reduce the occurrence of powder falling off from the prepreg, for example, Patent Document 1 discloses a resin composition containing an epoxy resin, a curing agent such as dicyandiamide, and a crosslinked rubber having a particle size of 1 μm or less. Further, Patent Document 2 discloses an epoxy resin composition containing an epoxy resin and a phenoxy resin modified with an acid anhydride.

Japanese Unexamined Patent Publication No. 2001-302813 Japanese Unexamined Patent Publication No. 2000-336242

However, in the prepregs produced from the resin compositions described in Patent Literature 1 and Patent Literature 2, although the occurrence of powder falloff is reduced to some extent, good moldability and high adhesion to the base material cannot be realized at the same time. And in the resin composition described in Patent Document 2, it is difficult to form a cured product having a low coefficient of thermal expansion.

An object of the present disclosure is to provide a prepreg having good formability and high adhesion to a base material and less occurrence of powder fall-off, and a resin composition capable of forming a cured product having a low coefficient of thermal expansion, and production from this resin composition It is to provide a metal clad laminated board, a printed wiring board and a flex-rigid printed wiring board containing a prepreg and a cured product of this resin composition.

The resin composition according to the present disclosure contains (A) an epoxy resin, (B) dicyandiamide, (C) a phenoxy resin, (D) a core shell rubber, and (E) an inorganic filler. (C) The weight average molecular weight of phenoxy resin is 30000 or more. (C) The tensile elongation of the phenoxy resin is 20% or more. (C) The content of the phenoxy resin is 5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the (A) epoxy resin. (D) The content of the core-shell rubber is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the (A) epoxy resin.

The prepreg according to the present disclosure has a fiber substrate and a semi-cured material of a resin composition impregnated in the fiber substrate.

A metal clad laminate according to the present disclosure has an insulating layer containing a cured product of a resin composition, and a metal layer provided on the insulating layer.

A printed wiring board according to the present disclosure has an insulating layer containing a cured product of a resin composition, and conductor wiring provided on the insulating layer.

A flex-rigid printed wiring board according to the present disclosure has a plurality of rigid parts, a flex part connecting the plurality of rigid parts, and a conductor wiring provided in at least one of the plurality of rigid parts and the flex part, and at least one of the plurality of rigid parts includes a cured product of a resin composition.

According to the present disclosure, a prepreg having good moldability and high adhesion to a base material and less occurrence of powder fall-off, and a resin composition capable of forming a cured product having a low coefficient of thermal expansion, and produced from the resin composition A metal clad laminated board, a printed wiring board, and a flex-rigid printed wiring board containing a prepreg and a cured product of this resin composition can be obtained.

1 is a cross-sectional view of a prepreg according to an embodiment of the present disclosure.
2 is a cross-sectional view of a metal clad laminate according to an embodiment of the present disclosure.
3A is a cross-sectional view of a printed wiring board having a single-layer structure, according to an embodiment of the present disclosure.
3B is a cross-sectional view of a multi-layered printed wiring board according to an embodiment of the present disclosure.
4 is a cross-sectional view of a flex-rigid printed wiring board according to the first embodiment of the present disclosure.
5 is a cross-sectional view of a flex-rigid printed wiring board according to a second embodiment of the present disclosure.
6 is a cross-sectional view of a flex-rigid printed wiring board according to a third embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described.

[Resin composition according to the present embodiment]

The resin composition (hereinafter referred to as composition (X)) according to the present embodiment includes (A) an epoxy resin, (B) dicyandiamide, (C) a phenoxy resin, and (D) a core shell rubber , (E) contains an inorganic filler. (C) The weight average molecular weight of phenoxy resin is 30000 or more. (C) The tensile elongation of the phenoxy resin is 20% or more. (C) The content of the phenoxy resin is 5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the (A) epoxy resin. (D) The content of the core-shell rubber is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the (A) epoxy resin.

In the present embodiment, since the composition (X) has the above structure, the prepreg produced from the composition (X) has good formability and high adhesion to the substrate, and there is little powder drop-off. In addition, the cured product of the composition (X) has a low coefficient of thermal expansion.

The components contained in the composition (X) will be described in more detail.

<(A) Epoxy Resin>

(A) The epoxy resin (hereinafter referred to as component (A)) can impart thermosetting properties to the composition (X). In addition, when the composition (X) contains the component (A), the cured product of the composition (X) can have good heat resistance.

Examples of the component (A) include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolak-type epoxy resins; Biphenyl type epoxy resin, xylylene type epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, biphenyl novolac type epoxy resin, biphenyl dimethylene type epoxy resin, trisphenol methane novolak type aryl alkylene type epoxy resins such as epoxy resins and tetramethyl biphenyl type epoxy resins; naphthalene type epoxy resins such as tetrafunctional naphthalene type epoxy resins; Naphthalene skeleton modification of naphthalene skeleton modified cresol novolak type epoxy resin, naphthalene diol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, methoxy naphthalene modified cresol novolak type epoxy resin, methoxy naphthalene dimethylene type epoxy resin, etc. epoxy resin; triphenylmethane type epoxy resin; Anthracene type epoxy resin; dicyclopentadiene type epoxy resins; norbornene type epoxy resin; fluorene type epoxy resin; Flame retardant epoxy resin obtained by halogenating the epoxy resin; A phosphorus modified epoxy resin etc. are mentioned. (A) component may be used individually by 1 type among these, and may use 2 or more types together.

When the composition (X) contains a bisphenol A-type epoxy resin having a weight average molecular weight of 30000 or more and a tensile elongation of 20% or more, the bisphenol A-type epoxy resin is the composition as the phenoxy resin of component (C) ( X) is contained in Therefore, the bisphenol A type epoxy resin contained as component (A) is a bisphenol A type epoxy resin having a weight average molecular weight of less than 30000, a bisphenol A type epoxy resin having a tensile elongation of less than 20%, or a weight average molecular weight of less than 30000 Further, it is a bisphenol A type epoxy resin having a tensile elongation of less than 20%.

(A) It is preferable that component contains a phosphorus modified epoxy resin. The phosphorus-modified epoxy resin means an epoxy resin containing a phosphorus atom. When the component (A) contains a phosphorus-modified epoxy resin, flame retardancy can be imparted to the cured product of the composition (X) without adding a halogen-based flame retardant, which is environmentally friendly.

The phosphorus-modified epoxy resin is not particularly limited. For example, a phosphorus-modified epoxy resin obtained by reacting an organic phosphorus compound with a quinone compound and reacting a reaction product generated in this reaction with an epoxy resin can be used.

(A) When a component contains a phosphorus-modified epoxy resin, it is preferable that a phosphorus-modified epoxy resin has a structure represented by following formula (1). In this case, the cured product of the composition (X) may have excellent flame retardancy.

The content of component (A) is preferably within the range of 40 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of composition (X). In this case, the composition (X) may have sufficient thermosetting properties. The content of component (A) is more preferably within the range of 50 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of composition (X).

When the component (A) contains a phosphorus-modified epoxy resin, the phosphorus-modified epoxy resin is preferably contained so that the phosphorus concentration in 100 parts by mass of the component (A) is 1% or more. In this case, the cured product of composition (X) can have higher flame retardance. It is more preferable that the phosphorus-modified epoxy resin is contained so that the phosphorus concentration in 100 parts by mass of component (A) is 1.5% or more.

<(B) dicyandiamide>

(B) dicyandiamide (hereinafter referred to as component (B)) functions as a curing agent. When the composition (X) contains the component (B) as a curing agent, the curing rate when the composition (X) is heated and cured is slowed compared to the case where, for example, a phenolic curing agent is contained, the composition (X ) of semi-cured material and hardened material are difficult to become brittle. For this reason, powder fall-off of the prepreg produced from composition (X) can be reduced. In addition, when the composition (X) contains the component (B) as a curing agent, compared to the case where the phenolic curing agent is contained, the semi-cured product and the cured product of the composition (X) have higher adhesion to the polyimide substrate in particular. have Since the polyimide substrate is suitably used as a cover lay of a printed wiring board or the like, a prepreg produced from the composition (X) can be effectively used as a substrate material for producing a printed wiring board.

Component (B) is contained in the composition (X) so that the active hydrogen equivalent of component (B) is within the range of 0.3 or more and 0.8 or less with respect to 1 epoxy equivalent of component (A), preferably 0.4 It is more preferable that it is contained so that it may fall within the range of 0.7 or less. On the other hand, the epoxy equivalent is the ratio of the molecular weight of the epoxy resin to the number of epoxy groups contained in the molecule of the epoxy resin. In addition, the active hydrogen equivalent is the ratio of the molecular weight of the compound used as a curing agent to the number of active hydrogens directly connected to the nitrogen atom of the amino group in the compound used as a curing agent.

<(C) Phenoxy Resin>

(C) The phenoxy resin (hereinafter referred to as component (C)) is a linearly polymerized resin by a condensation reaction between bisphenols and epichlorohydrin. Component (C) imparts flexibility to the prepreg produced from the composition (X), and can reduce the occurrence of powder fall-off. In addition, when the composition (X) contains the component (C), the semi-cured and cured products of the composition (X) can have particularly good adhesion to the polyimide substrate.

(C) The weight average molecular weight of component is 30000 or more. (C) When the component has a weight average molecular weight of 30000 or more, occurrence of powder drop-off of the prepreg prepared from the composition (X) can be reduced. (C) Although the upper limit of the weight average molecular weight of component is not specifically limited, For example, it is preferable that it is 100000 or less.

(C) The tensile elongation rate of component is 20 % or more. Since the tensile elongation of component (C) is 20% or more, sufficient flexibility can be imparted to the prepreg produced from the composition (X), so that the prepreg produced from the composition (X) can reduce powder fall-off. there is. The measurement of tensile elongation can be performed using an autograph.

As the component (C), for example, product numbers "YP-50" and "YP50S" manufactured by Nippon-Steel Sakekin Chemical Co., Ltd. can be used.

The content of component (C) is 5 to 30 parts by mass with respect to 100 parts by mass of component (A). When the content of component (C) is within this range, it is possible to reduce the occurrence of powder fall-off of the prepreg produced from the composition (X) without reducing the moldability of the prepreg produced from the composition (X). In addition, when the content of component (C) is within this range, the adhesiveness of the semi-cured and cured product to the polyimide substrate is less likely to decrease, so the semi-cured and cured product of the composition (X) It can have good adhesion to the polyimide substrate.

<(D) Core Shell Rubber>

(D) The core-shell rubber (hereinafter referred to as component (D)) is a prepreg produced from the composition (X) without significantly affecting the glass transition temperature of the cured product when the composition (X) is cured. Flexibility can be imparted to the cured product. For this reason, powder fall-off of the prepreg produced from composition (X) is reduced. In addition, when the composition (X) contains the component (D), the composition (X) has good impregnability to substrates, and a prepreg produced from the composition (X) can have good moldability.

Component (D) is an aggregate of rubber particles. The rubber particle has a core portion and a shell portion surrounding the core portion. That is, the rubber particle is a composite material containing different materials for the core portion and the shell portion, respectively.

The core portion is not particularly limited, but may also include, for example, silicone/acrylic rubber, acrylic rubber, silicone rubber, nitrile rubber, butadiene rubber, and the like. It is preferable that the core part contains silicone/acrylic rubber or acrylic rubber. In this case, higher flexibility can be imparted to the prepreg and cured product produced from the composition (X).

The shell portion is not particularly limited, but may consist, for example, of a plurality of graft chains bonded to the core portion. The graft chain may have a functional group. As a functional group, a methacryl group, an acryl group, a vinyl group, an epoxy group, an amino group, a ureido group, a mercapto group, and an isocyanate group are mentioned, for example. In addition, the shell part may be constituted of polymers such as polymethyl methacrylate and polystyrene, for example.

The shape and particle size of the rubber particles are not particularly limited. It is preferable that the average particle diameter of rubber particle is 0.1-2.0 micrometer, for example. The average particle diameter of the rubber particles is the volume-based median diameter calculated from the measured values of the particle size distribution by the laser diffraction/scattering method, and is obtained using a commercially available laser analysis/scattering type particle size distribution analyzer.

(D) As a component, for example, product numbers "SRK200A", "S2100", "SX-005", "S-2001", "S-2006", "S-2030", "S" manufactured by Mitsubishi Rayon Co., Ltd. -2200”, “SX-006”, “W-450A”, “E-901”, “C-223A”; Part number "AC3816", "AC3816N", "AC3832", "AC4030", "AC3364", "IM101" made by Aika Kogyo Co., Ltd.; "MX-217", "MX-153", "MX-960", etc. made by Kaneka Co., Ltd. can be used.

The content of component (D) is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of component (A). When the content of component (D) is within this range, the prepreg produced from composition (X) can have good substrate adhesion. Moreover, in this case, it can suppress that the thermal expansion coefficient of the hardened|cured material of composition (X) becomes high too much.

<(E) inorganic filler>

When the composition (X) contains the (E) inorganic filler (hereinafter referred to as component (E)), the cured product of the composition (X) can have a low coefficient of thermal expansion. When composition (X) contains component (D), the thermal expansion coefficient of the hardened|cured material of composition (X) tends to become high. However, since the cured product of composition (X) can have a low coefficient of thermal expansion by containing component (E) in composition (X), even if the cured product of composition (X) receives thermal stress, deformation such as warping or Less occurrence of cracks.

Component (E) is not particularly limited, and examples thereof include aluminum hydroxide, silica, barium sulfate, silicon oxide powder, crushed silica, calcined talc, zinc molybdate-coated talc, barium titanate, titanium oxide, clay, Alumina, mica, boehmite, zinc borate, zinc stannate, other metal oxides or metal hydrates, calcium carbonate, magnesium hydroxide, magnesium silicate, short glass fibers, aluminum borate whiskers, silicon carbonate whiskers, and the like may also be included. (E) As a component, these inorganic fillers may be used individually by 1 type, and may use 2 or more types together. Component (E) preferably contains at least one of aluminum hydroxide and silica.

(E) The shape and particle size of component are not specifically limited. (E) It is preferable that the average particle diameter of component is 0.1-5.0 micrometer, for example. The average particle diameter of component (E) is a volume-based median diameter calculated from measured values of particle size distribution by a laser diffraction/scattering method, and is obtained using a commercially available laser analysis/scattering particle size distribution analyzer.

(E) Component may be subjected to surface treatment with a coupling agent or the like. As a result, the adhesion of the cured product of the composition (X) to the substrate can be improved. As a coupling agent, silane coupling agents, such as an epoxysilane coupling agent and a mercaptosilane coupling agent, can be used, for example.

It is preferable that content of component (E) is 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of component (A). When the content of the component (E) is within this range, the thermal expansion coefficient of the cured product of the composition (X) can be lowered without adversely affecting the powder drop-off property of the prepreg produced from the composition (X). The content of component (E) is more preferably 10 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of component (A).

<Other ingredients>

Composition (X) may contain components other than the above components (A), (B), (C), (D) and (E), as long as the effects of the present invention are not impaired. . Composition (X) may contain, for example, a dispersant, a colorant, an adhesion imparting agent, a curing accelerator, an organic solvent, other resins, and additives.

Composition (X) may contain resins other than component (A) and component (C), for example, if the effect of the present invention is not impaired. Composition (X) may contain, for example, a phenol resin, a bismaleimide resin, or a cyanate resin.

In addition, composition (X) may contain, for example, a curing agent other than component (B), in the case where the effect of the present invention is not impaired. Examples of curing agents other than component (B) include amine-based curing agents other than dicyandiamide, urea-based curing agents, and acid anhydride-based curing agents.

[Prepreg 1 according to the present embodiment]

Referring to Fig. 1, a prepreg 1 according to the present embodiment will be described.

The prepreg 1 according to the present embodiment has a fiber substrate 12 and a semi-cured product 11 of the composition (X) impregnated into the fiber substrate 12.

Although the fiber base material 12 is not particularly limited, for example, a woven fabric base material such as a plain weave base material in which warp yarns and weft yarns are woven so that they are substantially orthogonal to each other can be used. As the fiber substrate 12, a woven fabric substrate composed of inorganic fibers, a woven fabric substrate composed of organic fibers, and the like can be used, for example. Examples of the woven fabric substrate made of inorganic fibers include glass cloth and the like. Examples of the woven fabric substrate made of organic fibers include aramid cloth and polyester cloth.

The prepreg 1 can be formed, for example, by impregnating the fiber substrate 12 with the composition (X) and heating and drying it until it becomes a semi-cured state. Temperature conditions and time at the time of making it into a semi-hardened state can be made into 170-200 degreeC and 30-90 minutes, for example. On the other hand, the semi-cured state is a so-called B-stage state in prepreg or the like. That is, it is a resin composition in an intermediate stage of curing a resin composition in an A-stage state (varnish state) to a C-stage state (cured state) by heating.

Since the prepreg 1 formed in this way is formed using the composition (X), as described above, it not only has good formability and high adhesion to the substrate, but also has little powder fall-off. For this reason, when handling the prepreg 1 or when producing a laminated sheet from the prepreg 1, powder dropout that occurs causes the produced laminated sheet to be dented like a dent, and the occurrence of defective dents can be suppressed. For example, in the case of manufacturing a flex-rigid printed wiring board using the prepreg 1 as described later, the prepreg 1 is punched out by mold processing or the like to provide an opening in the prepreg 1 and use it. there is. When the prepreg 1 provided with openings is laminated on a core material used for manufacturing a flex-rigid printed wiring board, dents are formed on the core material due to powder falling off from the end face of the prepreg 1 or the inner circumferential surface of the opening. It is possible to prevent the occurrence of defects or the occurrence of defects due to dropped powder. Therefore, the prepreg 1 formed using the composition (X) can be effectively used as a material for manufacturing a high-performance printed wiring board.

[Metal clad laminated board 2 according to the present embodiment]

Referring to Fig. 2, a metal clad laminated board 2 according to the present embodiment will be described.

The metal clad laminate 2 according to the present embodiment has an insulating layer 10 containing a cured product of the composition (X) and a metal layer 20 provided on the insulating layer 10 .

The metal layer 20 is provided on at least one side of the insulating layer 10 . That is, the structure of the metal clad laminated board 2 may be a two-layer structure including the insulating layer 10 and the metal layer 20 disposed on one side of the insulating layer 10, and the insulating layer 10 and the insulating layer A three-layer structure having two metal layers 20 arranged on both sides of the layer 10 may be used. 2 is a cross-sectional view of a metal clad laminated board 2 having a three-layer structure.

The metal clad laminated board 2 is formed by, for example, superimposing a metal foil on one or both surfaces of one or a plurality of prepregs 1 having a semi-cured material of the composition (X), heating and press-molding to integrate the lamination. can be produced Lamination molding can be performed by heating and pressurizing, for example, using a multi-stage vacuum press, hot press, double belt, or the like. In this case, the insulating layer 10 is produced by curing the prepreg 1.

The metal clad laminated board 2 may be manufactured without using the prepreg 1. For example, the varnish-like composition (X) is applied directly to the surface of the metal layer 20 made of metal foil, and the metal layer 20 and the composition (X) are heated and pressurized to obtain the varnish-like composition (X). The insulating layer 10 can be produced by curing.

Since the insulating layer 10 of the metal clad laminated board 2 formed as described above contains a cured product of the composition (X), the coefficient of thermal expansion is low. For this reason, even if the metal clad laminated board 2 is subjected to thermal stress, warping or cracking is unlikely to occur. Therefore, the metal clad laminated board 2 having the insulating layer 10 containing the cured product of the composition (X) can be effectively used as a substrate material for manufacturing a high-performance printed wiring board.

[Printed wiring boards 3 and 4 according to the present embodiment]

Referring to Figs. 3A and 3B, the printed wiring boards 3 and 4 according to the present embodiment will be described.

The printed wiring boards 3 and 4 according to the present embodiment have an insulating layer 10 containing a cured product of the composition (X) and a conductor wiring 30 provided on the insulating layer 10 .

The printed wiring board 3 (hereinafter sometimes referred to as a core material) includes one insulating layer 10 containing a cured product of the composition (X) and conductor wiring provided on one or both surfaces of the insulating layer 10. It is a single layer structured printed wiring board provided with (30). 3A is a cross-sectional view of a printed wiring board 3 having a single-layer structure including one insulating layer 10 and two conductor wires 30 provided on both surfaces of the one insulating layer 10 . A through hole, a via hole, etc. may be formed in the printed wiring board 3 of single-layer structure as needed.

The printed wiring board 4 is configured by alternately forming further insulating layers 10 and conductor wiring 30 on the surface of the core material 3 on which the conductor wiring 30 is formed, and the conductor wiring is provided on the outermost layer. (31) is a printed wiring board having a multilayer structure. In the printed wiring board 4 having a multilayer structure, at least one of the plurality of insulating layers 10 contains a cured product of the composition (X). In the printed wiring board 4 having a multilayer structure, it is preferable that all of the plurality of insulating layers 10 contain a cured product of the composition (X). 3B is a cross-sectional view of a printed wiring board 4 having a multilayer structure including three insulating layers 10 and four conductor wires 30 . In the printed wiring board 4 of the multilayer structure, a through hole, a via hole, or the like may be formed as needed.

The method for manufacturing the printed wiring board 3 having a single layer structure is not particularly limited, and for example, a part of the metal layer 20 of the metal clad laminated board 2 described above is removed by etching to form the conductor wiring 30. subtractive method; After forming a thin electroless plating layer by electroless plating on one side or both sides of the unclad plate made of the insulating layer 10 containing the cured product of the composition (X), and protecting the non-circuit forming part with a plating resist, A semi-additive method in which a thick electrolytic plating layer is applied to the circuit forming portion by electrolytic plating, then the plating resist is removed, and the electroless plating layer other than the circuit forming portion is removed by etching to form the conductor wiring 30. can be heard It does not specifically limit as a manufacturing method of the printed wiring board 4 of multilayer structure, For example, a build-up process etc. are mentioned.

[Flex-rigid printed wiring board 5 according to the first embodiment]

Referring to Fig. 4, a flex-rigid printed wiring board 5 according to the first embodiment will be described.

A flex-rigid printed wiring board 5 according to the first embodiment includes a plurality of rigid portions 51, a flex portion 52 connecting the plurality of rigid portions 51, a plurality of rigid portions 51 and a flex A conductor wiring 30 (32) is provided on at least one of the portions 52, and at least one of the plurality of rigid portions 51 includes a cured product of the composition (X). Specifically, the flex-rigid printed wiring board 5 according to the first embodiment includes two rigid portions 51, one flex portion 52, and a conductor wiring 30 (32), and the rigid portion At least one of the plurality of insulating layers 10 provided in (51) contains a cured product of composition (X).

The rigid part 51 is a hard part having hardness and strength capable of enduring the weight of mounted components and being fixed to the housing body. The flex portion 52 is a flexible portion having flexibility that can be bent. The flex-rigid printed wiring board 5 is used, for example, in small and lightweight devices such as portable electronic devices by being bent at the flex portion 52 and accommodated in a housing body or the like. It is preferable that the thickness of the flex part 52 is in the range of 5-300 micrometers, for example. In this case, the flex portion 52 has good flexibility.

The flex-rigid printed wiring board 5 can be manufactured by using, for example, a flexible printed wiring board 200 having a single-layer structure having one insulating layer 50 and two conductor wirings 30 as a core material. The rigid portion 51 is formed by multilayering the core material 200 except for the portion that becomes the flex portion 52 . That is, a part of the core material 200 becomes the flex part 52, and the other part of the core material 200 becomes the rigid part 51. The material of the insulating layer 50 in the core material 200 is not particularly limited as long as it is a material having flexibility, and may include, for example, a resin having flexibility such as polyimide. In addition, the method for multilayering is not specifically limited, A well-known method is used. For example, it can multilayer by the build-up method using the resin sheet with metal foil which has a resin layer containing metal foil and composition (X). The resin sheet with metal foil is produced, for example, by applying composition (X) to metal foil and heating and drying until composition (X) becomes a semi-cured state (B stage state). In a plurality of regions in which the rigid portion 51 in the core material 200 is formed, a resin sheet with metal foil is overlapped on each of both surfaces of the core material 200, and in this state, by heating and pressing molding, resin with metal foil The resin layer containing the composition (X) of the sheet is adhered to the core material 200, and the resin layer containing the composition (X) is cured to form the insulating layer 10 of the rigid portion 51. Then, the conductor wiring 32 is formed in the rigid part 51 by performing an etching process etc. to the metal foil derived from the resin sheet with metal foil. Thus, while the rigid portion 51 is formed, the flex portion 52 connecting the rigid portion 51 is formed.

In the flex-rigid printed wiring board 5 shown in FIG. 4 , the rigid portion 51 includes a part of the core material 200, an insulating layer 10 provided on the core material 200, and the insulating layer 10 Although the conductor wiring 32 provided on it is included, it is not limited to this, The rigid part 51 may be equipped with the solder resist layer provided in the outermost layer, for example. The rigid portion 51 may have a structure in which two or more insulating layers 10 and two or more conductor wires 32 are alternately provided on each of both sides of the core material 200 . That is, the rigid portion 51 may be further multilayered by a build-up method or the like. In the rigid part 51, a through hole, a via hole, etc. may be formed as needed.

In the flex-rigid printed wiring board 5 shown in FIG. 4 , the flex portion 52 includes an insulating layer 50 that is a part of the core material 200 . That is, the flex portion 52 is a part of the insulating layer 50 . The configuration of the flex portion 52 is not limited to this, and the flex portion 52 may include, for example, the conductor wiring 30 . That is, the conductor wiring 30 may be formed on the insulating layer 50 of the flex part 52 . In addition, a cover lay covering the conductor wiring 30 of the core material 200 may be provided. In this case, the flex portion 52 includes the insulating layer 50, the conductor wiring 30, and the cover lay do. The insulating layer 50 may have a single-layer structure composed of one insulating layer, or may have a multi-layer structure in which a plurality of insulating layers are laminated. In the case where the flexibility of the flex portion 52 is not hindered, the flex portion 52 may have a multilayer structure. In this case, for example, by using a flexible printed wiring board having a multilayer structure as a core material, a rigid flex printed wiring board can be obtained. can be produced.

In the flex-rigid printed wiring board 5 shown in Fig. 4, at least one of the plurality of insulating layers 10 contains a cured product of the composition (X). That is, at least one of the plurality of rigid portions 51 includes a cured product of the composition (X).

[Flex-rigid printed wiring board 6 according to the second embodiment]

Referring to Fig. 5, a flex-rigid printed wiring board 6 according to a second embodiment will be described. Hereinafter, the same reference numerals are given to components similar to those of the flex-rigid printed wiring board 5 according to the first embodiment, and detailed explanations are omitted.

A flex-rigid printed wiring board 6 according to the second embodiment includes a plurality of rigid portions 51, a flex portion 52 connecting the plurality of rigid portions 51, a plurality of rigid portions 51 and a flex A conductor wiring 30 (32) is provided on at least one of the portions 52, and at least one of the plurality of rigid portions 51 includes a cured product of the composition (X). Specifically, the flex-rigid printed wiring board 6 according to the second embodiment includes two rigid portions 51, one flex portion 52, and a conductor wiring 30 (32), and the rigid portion At least one of the plurality of insulating layers 10 provided in (51) contains a cured product of composition (X).

In the flex-rigid printed wiring board 6 according to the second embodiment, a solder resist layer 60 is provided on the outermost layer of the rigid portion 51 . In addition, a cover lay 40 covering the conductor wiring 30 of the core material 200 is provided. In addition, a through hole 101 and a buried via hole 102 are formed in the rigid portion 51 . The structure of the flex-rigid printed wiring board 6 is not limited to this, and the flex-rigid printed wiring board 6 does not need to have the solder resist layer 60. In addition, the flex-rigid printed wiring board 6 does not need to have the cover lay 40. A blind via hole may be additionally formed in the rigid portion 51 as needed.

The flex-rigid printed wiring board 6 can be manufactured by using, for example, a flexible printed wiring board 200 having a single-layer structure having one insulating layer 50 and two conductor wirings 30 as a core material. The material of the insulating layer 50 in the core material 200 is not particularly limited as long as it is a material having flexibility, and may include, for example, a resin having flexibility such as polyimide. A cover lay 40 covering the conductor wiring 30 is formed by laminating cover lay films on both surfaces of the core material 200 . In this way, the flexible printed wiring board 300 having the core material 200 and the cover lay 40 is produced. The rigid portion 51 is formed by multilayering the flexible printed wiring board 300 excluding the portion that becomes the flex portion 52 . That is, a part of the flexible printed wiring board 300 becomes the flex portion 52 and another portion of the flexible printed wiring board 300 becomes the rigid portion 51 . The method for multilayering is not particularly limited, and a known method is used, and multilayering can be performed by, for example, the same method as for the flex-rigid printed wiring board 5 of the first embodiment described above. Specifically, using a resin sheet with metal foil having a resin layer containing metal foil and the composition (X), it can be multilayered by a build-up method. The resin sheet with metal foil is produced by applying composition (X) to metal foil and heating and drying until composition (X) becomes a semi-cured state (B stage state). In a plurality of regions where the rigid portion 51 in the flexible printed wiring board 300 is formed, a resin sheet with metal foil is overlapped on each of both surfaces of the flexible printed wiring board 300, and in this state, by heating and pressing, the metal foil While the resin layer containing the composition (X) of the attached resin sheet is adhered to the flexible printed wiring board 300, the resin layer containing the composition (X) is cured, and the insulating layer containing the cured product of the composition (X) ( 10) is formed on the rigid portion 51. Then, the conductor wiring 32 is formed in the rigid part 51 by performing an etching process etc. to the metal foil derived from the resin sheet with metal foil. The formation of the insulating layer 10 and the formation of the conductor wiring 32 are alternately repeated to form the solder resist layer 60 as the outermost layer. Thus, while the rigid portion 51 is formed, the flex portion 52 connecting the rigid portion 51 is formed. The through hole 101 and the buried via hole 102 can be formed by a known method.

As another method for producing the flex-rigid printed wiring board 6, a prepreg 1 having a fiber substrate 12 shown in FIG. 1 and a semi-cured material 11 of the composition (X) impregnated into the fiber substrate 12 You can find out how to use it. An opening is made in the prepreg 1 by punching out the prepreg 1 by mold processing or the like. This opening corresponds to the flex portion 52 of the flex-rigid printed wiring board 6. The prepreg 1 having an opening is superimposed on the flexible printed wiring board 300 and heated and pressed in this state to cure the prepreg 1, thereby forming an insulating layer 10 containing a cured product of the composition (X). It is formed on this rigid part 51. On the other hand, since the opening of the prepreg 1 corresponds to the flex portion 52, the insulating layer 10 is not formed in the flex portion 52. Subsequently, on the insulating layer 10, the conductor wiring 32 is formed by a known method. Formation of the insulating layer 10 using the prepreg 1 having an opening and formation of the conductor wiring 32 are alternately repeated to form the solder resist layer 60 as the outermost layer. Thus, while the rigid portion 51 is formed, the flex portion 52 connecting the rigid portion 51 is formed.

[Flex-rigid printed wiring board 7 according to the third embodiment]

Referring to Fig. 6, a flex-rigid printed wiring board 7 according to a third embodiment will be described. Hereinafter, the same reference numerals are given to components similar to those of the flex-rigid printed wiring board 5 according to the first embodiment and the flex-rigid printed wiring board 6 according to the second embodiment, and detailed descriptions thereof are omitted.

A flex-rigid printed wiring board 7 according to the third embodiment includes a plurality of rigid portions 51, a flex portion 52 connecting the plurality of rigid portions 51, a plurality of rigid portions 51 and a flex A conductor wiring 30 (32) is provided on at least one of the portions 52, and at least one of the plurality of rigid portions 51 includes a cured product of the composition (X). Specifically, the flex-rigid printed wiring board 7 according to the third embodiment includes two rigid portions 51, one flex portion 52, and a conductor wiring 30 (32), and the rigid portion At least one of the plurality of bonding sheets 70 provided in (51) contains a cured product of the composition (X).

In the flex-rigid printed wiring board 7 according to the third embodiment, a cover lay 40 covering the conductor wiring 30 of the core material 200 is provided. In addition, a through hole 101 and a blind via hole 103 are formed in the rigid portion 51 . The configuration of the flex-rigid printed wiring board 7 is not limited to this, and the flex-rigid printed wiring board 7 does not need to have the cover lay 40. Further, a buried via hole may be additionally formed in the rigid portion 51 as needed. Moreover, the rigid part 51 may be equipped with the solder resist layer provided in the outermost layer.

The flex-rigid printed wiring board 7 includes, for example, a flexible printed wiring board 300 similar to that used to manufacture the flex-rigid printed wiring board 6 of the second embodiment, a rigid printed wiring board 400, It can be manufactured using the prepreg 1 shown in FIG. The flexible printed wiring board 300 has a core material 200 including one insulating layer 50 and two conductor wires 30 and two cover lays 40 . The rigid printed wiring board 400 is a multi-layered printed wiring board having two insulating layers 10 and three conductor wires 32, and blind via holes 103 are formed using a known method. First, an opening is made in the prepreg 1 by punching the prepreg 1 through mold processing or the like. This opening corresponds to the flex portion 52 of the flex-rigid printed wiring board 7 . A prepreg 1 having an opening is superimposed on a flexible printed wiring board 300, and a rigid printed wiring board 400 is superimposed on each of the prepregs 1. By heating and pressing in this state, the prepreg 1 is cured to form a bonding sheet 70 containing the composition (X), and the flexible printed wiring board 300 and the rigid printed wiring board 400 are bonded to the bonding sheet ( 70) is bonded. After that, the through hole 101 can be formed by a known method. On the other hand, since the opening of the prepreg 1 corresponds to the flex portion 52, the bonding sheet 70 is not formed in the flex portion 52.

The structure of the rigid printed wiring board 400 is not limited to the structure shown in FIG. The rigid printed wiring board 400 may have the same configuration as the single-layer printed wiring board 3 shown in FIG. 3A having one insulating layer 10 and two conductor wirings 30, for example. In addition, the rigid printed wiring board 400 may have the same configuration as the multilayer printed wiring board 4 shown in FIG. 3B having three insulating layers 10 and four conductor wirings 30, and four A structure having an insulating layer 10 and five conductor wires 30 may be used. On the other hand, in the flex-rigid printed wiring board 7 of the third embodiment, the insulating layer 10 of the rigid printed wiring board 400 may or may not contain a cured product of the composition (X).

[Example]

Hereinafter, the present invention will be specifically described by examples.

1. Preparation of resin composition

Among the components shown in the "Composition" column of Tables 1 and 2 mentioned later, components excluding component (D), component (E) and curing accelerator were prepared using a mixed solvent of methyl ethyl ketone and dimethylformamide, They were mixed in the proportions shown in 1 and 2, and the mixture was stirred for 30 minutes. Next, to this mixture, the component (D), component (E), and curing accelerator shown in the "composition" column of Tables 1 and 2 are added in the proportions shown in Tables 1 and 2, and dispersed by a ball mill. Resin compositions (resin varnishes) of Examples 1 to 11 and Comparative Examples 1 to 13 were obtained.

Details of the components in the column of "composition" in Tables 1 and 2 are as follows.

・Phosphorus modified epoxy resin: manufactured by Nippon-Stetsu Sake & Chemicals Co., Ltd., product number FX-289

Bisphenol A type epoxy resin 1: manufactured by DIC Corporation, product number 850-S, epoxy equivalent 183 to 193 g/eq

Bisphenol A type epoxy resin 2: manufactured by Nippon Steel Sakekin Chemical Co., Ltd., product number YD-011, epoxy equivalent 450 to 500 g/eq

Bisphenol A type epoxy resin 3: manufactured by Nippon Steel Sake & Chemicals Co., Ltd., product number YD-927, epoxy equivalent 1750 to 2100 g/eq

Bisphenol A type epoxy resin 4: manufactured by Nippon Steel Sakekin Chemical Co., Ltd., part number YD-020, epoxy equivalent 4000 to 6000 g/eq

・Phenol resin: manufactured by DIC Corporation, part number TD-2093, hydroxyl equivalent 104

-Phenoxy resin 1: manufactured by Nippon Steel Sake & Chemicals Co., Ltd., product number YP-50, weight average molecular weight 70000, tensile elongation 33%

-Phenoxy resin 2: manufactured by Nippon Steel Sakekin Chemical Co., Ltd., part number YP50S, weight average molecular weight 60000, tensile elongation 30%

-Phenoxy resin 3: manufactured by Nippon Steel Sake & Chemicals Co., Ltd., product number YP-70, weight average molecular weight 55000, tensile elongation 10%

-Phenoxy resin 4: manufactured by Nippon Steel Sake & Chemicals Co., Ltd., part number ZX-1356-2, weight average molecular weight 70000, tensile elongation 12%

・Core shell rubber 1: silicone/acrylic rubber, manufactured by Mitsubishi Rayon Co., Ltd., product number SRK-200A

・Core shell rubber 2: Acrylic rubber, manufactured by Aika Kogyo Co., Ltd., product number AC-3816N

・Aluminum hydroxide: Sumitomo Chemical Co., Ltd., product number CL-303M

・Crushed silica: Sibelco Japan Co., Ltd., product number Megasil525

・Curing accelerator: 2-ethyl-4-imidazole, manufactured by Shikoku Kasei Co., Ltd., product number 2 E4MZ

On the other hand, the tensile elongation rates of phenoxy resin 1, phenoxy resin 2, and phenoxy resin 3 were measured as follows. Each resin plate (length 15 cm, width 1 mm, thickness 100 μm) of phenoxy resins 1 to 3 was prepared, and the tensile elongation of the resin plate was measured using an autograph (manufactured by Shimadzu Corporation, model number AG-IS), It was measured at 23±2°C and a tensile speed of 1 mm/min.

2. Preparation of prepreg

The resin varnish of each Example and Comparative Example is impregnated with a glass cloth (#1078 type, WEA1078 manufactured by Nitto Spinning Co., Ltd.) so that the thickness after curing is 80 μm, and heat-dried at 170 ° C. until the melt viscosity is 60000 to 150000 Poise As a result, a prepreg containing a semi-cured resin composition was obtained. On the other hand, the measurement of the melt viscosity is performed using a solidification type flow tester (CFT-100, manufactured by Shimadzu Corporation), the temperature of the flow tester is 130 ° C., and the pressure is 1.96 MPa (20 kgf / cm ² ) Conditions Below, a nozzle having a diameter of 1 mm and a thickness of 1 mm was used.

3. Fabrication of copper clad laminates

Copper foil (manufactured by Mitsui Mining & Mining Co., Ltd., 3EC-III) with a thickness of 18 μm was placed on both sides of one sheet of prepreg in Examples and Comparative Examples to form a body to be pressed, and the body to be pressed was 190° C. and 2.94 MPa (30 kgf/cm ² ) by heating and pressurizing for 60 minutes under a pressure of 80 μm in thickness to obtain a copper clad laminated board having copper foil adhered to both surfaces. Further, copper foil (3EC-III, manufactured by Mitsui Mining and Mining Co., Ltd.) having a thickness of 18 μm is placed on both sides of the laminated body in which 10 prepreg sheets of each Example and Comparative Example are laminated to form a body to be pressed, and this body to be pressed is the same as described above. By heating and pressurizing under the conditions of, a copper clad laminated board having a thickness of 800 μm in which copper foil was adhered to both surfaces was obtained. On the other hand, in forming the body to be pressed, a hot press was used to insert the body to be pressed in a state where the temperature of the hot plate of the molding machine was warmed to 100°C.

4. Assessment test

4-1. powder exfoliation

The prepregs of each Example and Comparative Example prepared in 2 above were cut into a size of 11 × 10 cm (length × width), and tested using them as test pieces. First, deposits such as powder and dust were removed from 10 test pieces using a handy mop. Next, the weight of 10 test pieces was measured. Subsequently, 10 incisions with a length of 10 cm were made at equal intervals using a cutter knife (A type cutter replaceable razor blade, manufactured by NT Corporation) into each of the 10 test pieces, and from the 10 test pieces into which the incisions were placed, Deposits such as powder and dust were removed. Then, the weight of 10 test pieces with incisions was measured. The value obtained by subtracting the weight of 10 test pieces after inserting the incision from the weight of 10 test pieces before inserting the incision was used as the amount of powder dropping. The percentage of the amount of powder falling off with respect to the weight of 10 test pieces before inserting the incision was taken as the powder dropping ability.

4-2. formability

Regarding the copper foil on both sides of the copper clad laminate having a thickness of 18 μm of each of the examples and comparative examples produced in 3 above, a lattice-like pattern was formed so that the residual copper ratio was 50%, respectively, to form conductor wiring, A printed wiring board was obtained. On the conductor wiring on both sides of this printed wiring board, one prepreg prepared in 2 above was laminated, respectively, and heated and pressurized for 60 minutes at 190°C and a pressure of 2.94 MPa (30 kgf/cm ² ) to obtain a laminate. . This laminate was cut into a size of 50 x 50 mm to obtain a test piece. After boiling this test piece for 4 hours, it was immersed in a 260 degreeC solder bath for 20 seconds, the external appearance of the test piece was observed, and the result was evaluated as shown below.

A: Puffiness is confirmed.

B: No swelling was observed.

4-3. Copper foil adhesion

The copper clad laminated board having a thickness of 18 μm of each Example and Comparative Example produced in 3 above was used as a test piece. The peel strength of the copper foil of this test piece was measured based on IPC-TM-650-2.4.8. A copper foil pattern having a width of 10 mm and a length of 100 mm was formed on the test piece, and the copper foil pattern was peeled off at a speed of 50 mm/min with a tensile tester, and the peel strength at that time was measured. This peeling strength was made into copper foil adhesiveness.

4-4. Adhesion to polyimide

A single-sided flexible metal clad laminate (manufactured by SK Innovation Co., Ltd., Enflex(R), copper foil thickness 12 μm, polyimide thickness 20 μm) and one prepreg sheet of each Example and Comparative Example produced in the above 2, and a single-sided flexible metal clad laminate The polyimide layer and the prepreg were laminated so as to be in contact with each other, and a laminate was produced by heating and pressurizing at 190°C and 2.94 MPa (30 kgf/cm ² ) for 60 minutes. This laminate was cut into a size of 10 x 100 mm to obtain a test piece. From this test piece, the single-sided flexible metal-clad laminate was peeled off at a speed of 50 mm/min with a tensile tester, and the peel strength at that time was measured. This peel strength was made into polyimide adhesiveness.

4-5. Glass transition temperature (Tg)

The copper foils on both sides of the copper clad laminate having a thickness of 80 μm of each Example and Comparative Example produced in 3 above were removed to obtain a test piece. The glass transition temperature (Tg) of this test piece was measured by differential scanning calorimetry (DSC) in accordance with IPC-TM-650-2.4.25 under conditions of a heating rate of 20°C/min. On the other hand, the numerical values in parentheses in the columns of glass transition temperature in Tables 1 and 2 indicate the glass transition temperature on the low-temperature side when the glass transition temperature is measured at two locations of the test piece.

4-6. Coefficient of Thermal Expansion (CTE)

The copper foil on both sides of the 800 μm-thick copper-clad laminate of each Example and Comparative Example produced in 3 above was removed to obtain a test piece. The coefficient of thermal expansion (CTE) of the test piece in the plane direction (thickness direction) was measured by the Thermo-mechanical analysis (TMA) method in accordance with JIS C 6481. On the other hand, the coefficient of thermal expansion was measured at a temperature less than the glass transition temperature measured in 4-5 above.

Comparing Example 2 and Comparative Example 13, the powder detachment property of Example 2 containing component (B) as a curing agent was lower than that of Comparative Example 13 containing a phenol resin as a curing agent, and furthermore, copper foil and polyimide Adhesion to is higher than that of Comparative Example 13. Further, when Example 1 and Comparative Example 10 are compared, the powder drop-off property of Example 1 containing component (C) is less than half of the powder drop-off property of Comparative Example 10 not containing component (C). In addition, when Example 3 and Comparative Example 7 are compared, the powder fall-off property of Example 3 containing component (D) is half of the powder fall-off property of Comparative Example 7 not containing component (D). As described above, it was confirmed that component (B), component (C), and component (D) reduce the occurrence of powder drop-off of the prepreg produced from composition (X). In addition, it was confirmed that component (B) improves adhesion to copper foil and polyimide.

In addition, as is clear from Tables 1 and 2, compared to Comparative Examples, the examples have characteristics of powder dropout, formability, copper foil and polyimide adhesion, glass transition temperature, and thermal expansion coefficient, and are obtained in a well-balanced level. It was confirmed that there is On the other hand, in the comparative example, a resin composition having all of these characteristics was not obtained.

1: prepreg
11: radius cargo
12: fiber substrate
2: metal clad laminate
10, 50: insulating layer
20: metal layer
3, 4: printed wiring board
30, 31, 32: conductor wiring
5, 6, 7: flex-rigid printed wiring board
51: rigid part
52: flex part

Claims (10)

a fiber substrate,
As a prepreg having a semi-cured material of the resin composition impregnated in the fiber substrate,
The resin composition
(A) an epoxy resin;
(B) dicyandiamide;
(C) a phenoxy resin;
(D) a core shell rubber;
(E) contains an inorganic filler;
The weight average molecular weight of the (C) phenoxy resin is 30000 or more,
The tensile elongation of the (C) phenoxy resin is 20% or more,
The content of the (C) phenoxy resin is 5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A),
The content of the (D) core shell rubber is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A),
The content of the (E) inorganic filler is 5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the (A) epoxy resin,
prepreg. According to claim 1,
The (D) core shell rubber is an aggregate of rubber particles,
The rubber particle has a core portion and a shell portion surrounding the core portion,
The core part includes silicone/acrylic rubber or acrylic rubber.
prepreg. According to claim 1,
The (A) epoxy resin contains a phosphorus-modified epoxy resin
prepreg. According to claim 3,
The phosphorus-modified epoxy resin has a structure represented by the following formula (1)
prepreg.

According to claim 2,
The (A) epoxy resin contains a phosphorus-modified epoxy resin
prepreg. According to claim 5,
The phosphorus-modified epoxy resin has a structure represented by the following formula (1)
prepreg.

An insulating layer containing a cured product of the prepreg resin composition according to any one of claims 1 to 6;
Having a metal layer installed on the insulating layer
metal clad laminate. An insulating layer containing a cured product of the prepreg resin composition according to any one of claims 1 to 6;
Having a conductor wiring installed in the insulating layer
printed wiring board. a plurality of rigid parts;
a flex portion connecting the plurality of rigid portions;
having a conductor wiring provided on at least one of the plurality of rigid portions and the flex portion;
At least one of the plurality of rigid portions includes a cured product of the prepreg resin composition according to any one of claims 1 to 6
Flex Rigid Printed Wiring Board. delete

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