JP4425118B2 - Flame retardant resin composition, metal-clad laminate for flexible printed wiring board using the composition, coverlay, adhesive sheet, and flexible printed wiring board - Google Patents

Description

  The present invention relates to a non-halogen flame retardant resin composition, and more specifically, to a flame retardant resin composition mainly used for adhesives such as composites made of glass fibers, polyimide, and metal foil in the field of electronic materials, and The present invention relates to a metal-clad laminate for a flexible printed wiring board, a coverlay, an adhesive sheet, and a flexible printed wiring board.

  Flame retardant resin compositions are used as adhesives in the field of electronic materials (especially printed wiring boards [more specifically, flexible printed wiring boards (hereinafter also referred to as FPC) including metal-clad laminates, etc.)]. Widely used, mainly metal foil (for example, copper foil) and film (for example, polyester film, polyimide film, etc.), or metal foils, films, a composite containing glass fibers, the metal foil, and the composite It is used as an adhesive when bonding films.

  In particular, the flame-retardant resin composition includes the film of a metal-clad laminate for flexible printed wiring boards (hereinafter, also referred to as a metal-clad laminate for FPC) in which a metal foil is laminated and adhered to one side or both sides of the film. It is useful as a resin composition used for bonding to a metal foil or a resin composition used for a coverlay bonded to a metal-clad laminate for FPC provided with a circuit.

  The coverlay is a laminate of a resin composition as an adhesive on a film of polyimide, polyethylene terephthalate, polyamide, polycarbonate or the like. It is used to prevent circuit disconnection when subjected to displacement, to maintain insulation of the circuit, and to prevent moisture from entering and rusting from the outside.

  Such a flame retardant resin composition is used for mechanical properties, electrical properties (for example, copper migration), and thermal properties to enhance the functionality of FPC using FPC metal-clad laminates and coverlays. In addition to being excellent in various properties such as chemical resistance and adhesiveness, high flame retardancy is required. Specifically, the flame retardant resin composition in the above field is required to have high flame retardancy of about V-0 level in the UL 94 standard which is a flame retardant standard.

  In the conventional flame retardant resin composition, in order to impart flame retardancy, in addition to a resin (for example, epoxy resin) and a curing agent, a flame retardant is incorporated in the chemical structure of the resin or a method of adding a flame retardant in advance. Flame retardancy is imparted to the resin composition itself by a method using the obtained resin.

  By the way, in the method of adding the flame retardant, the flame retardant is roughly classified into a halogen flame retardant (including a halogenated epoxy resin) and a non-halogen flame retardant.

  Many halogen-based flame retardants are used because they can be added in a small amount compared to non-halogen-based flame retardants and metal oxides and have high flame retardant efficiency. However, the amount of halogenated compounds (for example, bromine compounds) is decreasing due to environmental problems such as dioxins and environmental hormones generated during incineration. In particular, the use of halogenated compounds in the field of electronic materials is suppressed. The movement to do is becoming active.

  As non-halogen flame retardants, those that have reached a practical level can be divided into phosphorus flame retardants and metal oxides. These flame retardants are attracting attention as alternative flame retardants for halogen-based flame retardants, and the amount used is also steadily increasing.

  Phosphorus flame retardants (especially low molecular weight compounds such as phosphate ester compounds) are widely used as an alternative to halogen flame retardants in the field of electronic materials. However, it is presumed that the phosphoric flame retardant is easily hydrolyzed by the absorbed moisture, and the decomposed product significantly reduces the adhesive strength and the migration characteristics. Furthermore, it causes a decrease in the glass transition temperature and elastic modulus of the resin composition after curing.

  Therefore, in the field of electronic materials (particularly in the printed wiring board field), for example, when used as an adhesive between a polyimide film and a metal foil, the adhesive strength, electrical characteristics (especially migration characteristics), and flexibility at high temperatures are reduced. It is difficult to say that it is practical.

  In addition, metal oxides have a function of suppressing combustibility by lowering the combustion temperature with water liberated from the metal oxide during combustion, and it is usually difficult to express flame retardancy alone. Often used in combination with flame retardants. If this metal oxide is used alone, a large amount of addition is required in the resin composition. For this reason, handling property and moldability are remarkably deteriorated, and it is difficult to say that it is practical.

  By the way, in Japanese Patent Application Laid-Open No. 2001-2931, a resin containing phosphorus in a molecule (for example, a phosphorus-containing polyester resin) for the purpose of improving heat resistance, adhesiveness and the like to be used for applications such as adhesives for circuit boards. And a phosphorus-containing polyurethane resin), a flame-retardant resin composition containing a predetermined amount of a phosphorus-containing compound (such as ammonium polyphosphate) and, if necessary, a curing agent such as an epoxy resin or an isocyanate compound (Patent Document 1). ).

  However, since the flame retardant resin composition described in the publication contains a predetermined amount of a low molecular weight phosphorus-containing compound (phosphorus flame retardant) as described above, it is intended to be used, for example, as an adhesive for printed wiring boards. When, the adhesive strength and migration characteristics are significantly reduced due to hydrolysis of the phosphorus-containing compound by the absorbed moisture, and further the properties of the resin composition after curing and molding (glass transition temperature, elastic modulus, etc.) In particular, the effect is insufficient in the electrical characteristics of the printed wiring board after curing and molding. In addition, such a flame retardant resin composition has a problem that a satisfactory effect cannot be obtained particularly in flame retardancy and adhesiveness depending on the content ratio of the epoxy resin and the curing agent and phosphorus.

The flame-retardant resin composition is required to have excellent compatibility and molding processability of the composition before curing, in addition to various properties after curing and molding as an adhesive and the like.
JP 2001-2931 A

The problem to be solved by the present invention is to solve the above-mentioned problems of the prior art.
Therefore, the object of the present invention is excellent in compatibility and molding processability of the flame-retardant resin composition before curing, for example, adhesiveness after curing molding as an adhesive for printed wiring boards, and electrical characteristics of printed wiring boards. It is providing the flame-retardant resin composition which is excellent.

  The invention of claim 1 is a flame retardant resin composition to be bonded to a composite made of glass fibers in the field of electronic materials, a film, and a metal foil, a thermosetting resin, a curing agent, and a phosphorus-containing polyol. And a polyisocyanate and a metal-containing flame retardant, and the phosphorus in the phosphorus-containing polyol is in a ratio of 0.93% by weight or more with respect to the total amount of the thermosetting resin and the curing agent. And the amount of the phosphorus-containing polyol is 4 to 50 parts by weight with respect to 100 parts by weight of the thermosetting resin, and the amount of the polyisocyanate is 100 parts by weight of the thermosetting resin. On the other hand, it is 10 to 80 parts by weight, and the compounding amount of the metal-containing flame retardant is 10 to 200 parts by weight with respect to 100 parts by weight of the thermosetting resin. The object is achieved by providing a flame retardant resin composition in which a composite comprising fibers, a film, and a metal foil are applied and heated to react the phosphorus-containing polyol with the polyisocyanate. is there

In invention of Claim 2, the flame-retardant resin composition of Claim 1 whose said thermosetting resin is an epoxy resin is provided.

In invention of Claim 3, the glass transition temperature is 100 degreeC or more, The flame-retardant resin composition of Claim 1 or 2 is provided .

In the invention of Claim 4, the flame-retardant resin composition according to any one of Claims 1 to 3 is used as an adhesive for adhering a film and a metal foil. A metal-clad laminate for a wiring board is provided.

In invention of Claim 5, the flame-retardant resin composition in any one of Claims 1-3 is provided in the synthetic resin film which has electrical insulation, The coverlay characterized by the above-mentioned is provided. .

In invention of Claim 6, it consists of a flame-retardant resin composition in any one of Claims 1-3, The adhesive sheet for flexible printed wiring boards characterized by the above-mentioned is provided.

In a seventh aspect of the invention, a cover lay is formed from the flame retardant resin composition according to any one of the first to third aspects, and the cover lay is provided on a metal foil. Provide printed wiring board.

  According to the present invention, the composition before curing is excellent in compatibility and molding processability, for example, as an adhesive for printed wiring boards, adhesiveness after curing molding, and excellent electrical properties of printed wiring boards A resin composition is provided. Moreover, according to this invention, the outstanding metal-clad laminated board for flexible printed wiring boards, a coverlay, an adhesive sheet, and a flexible printed wiring board which use this flame-retardant resin composition are provided, respectively.

(Flame retardant resin composition)
The flame-retardant resin composition of the present invention is mainly suitably used for applications such as metal-clad laminates for flexible printed wiring boards, coverlays, adhesive sheets, and flexible printed wiring boards.
Here, the metal-clad laminate for flexible printed wiring board is a laminate of a film and a metal foil. The coverlay is provided to protect the circuit of the metal-clad laminate for a flexible printed wiring board provided with a conductor pattern (hereinafter also referred to as a circuit), for example, a synthetic resin film having electrical insulation. The resin composition is provided by means such as coating in a single layer or a laminated state of a plurality of layers. The flexible printed wiring board is a board in which a coverlay is provided in a necessary portion of a metal-clad laminate for a flexible printed wiring board provided with a circuit.

  The flame retardant resin composition of the present invention is preferably used mainly for the above applications, but can also be used for multilayer printed wiring boards, flex rigid printed wiring boards, and the like. Here, as a flex-rigid printed wiring board, a flex-rigid printed wiring board 40 having the form shown in FIG. 6 can be illustrated as an example. As shown in FIG. 6, the flex-rigid printed wiring board 40 includes an FPC 44 including a copper-clad laminate 41 having a circuit 42 formed thereon and a pair of coverlays 43 and 43 laminated on both sides thereof, and both sides of the FPC 44. A pair of rigid substrates 46, 46 having a prepreg as a core, adhesive sheets 45, 45 provided between the FPC 44 and the rigid substrates 46, 46, and copper foil are etched to form the rigid substrates. A plurality of circuits 47 formed on the surfaces of 46 and 46 and a through hole 48 for forming holes with a drill after the lamination in a predetermined circuit and performing copper plating are mainly configured. The prepreg here refers to a glass cloth that is impregnated with a thermosetting resin (a mixture of epoxy resin, BT resin, etc. with a curing agent, solvent, filler, additive, etc.), heat dried, and can be stored. A state in which curing has been advanced to a certain stable state to some extent.

(Flame-retardant resin composition of the first embodiment)
The flame retardant resin composition of the present invention is a flame retardant resin composition comprising, as the first embodiment, a thermosetting resin, a curing agent, a phosphorus-containing polyol, and a polyisocyanate. Provided is a flame retardant resin composition characterized in that phosphorus in the phosphorus-containing polyol is contained in a ratio of 0.93% by weight or more with respect to the total amount of the thermosetting resin and the curing agent. Is done.

  In the flame-retardant resin composition of the first embodiment, a phosphorus-containing polyol and a polyisocyanate having the property of imparting flame retardancy are blended, and the phosphorus-containing polyol and the polyisocyanate are selected by heat curing. React to form a phosphorus-containing polyurethane in the flame retardant resin composition. This phosphorus-containing polyurethane is presumed to be decomposed into a phosphorus-containing polyol and a polyisocyanate by heat during combustion and exhibit a high flame-retardant effect due to the flame-retardant effect and foaming effect of phosphorus.

  Furthermore, since thermosetting resin, curing agent, phosphorus-containing polyol and polyisocyanate are the basic components, the compatibility and molding processability of the flame-retardant resin composition before curing are improved, and the difficulty after curing molding. The adhesive properties and electrical properties of the flammable resin composition are also excellent.

The phosphorus in the phosphorus-containing polyol is contained in a ratio of 0.93% by weight or more with respect to the total amount of the thermosetting resin and the curing agent.
In particular, the phosphorus content needs to be 0.93% by weight or more from the viewpoint of exhibiting electrical properties such as glass transition temperature and migration of the composition after curing, adhesion, and flame retardancy. On the other hand, the phosphorus content is preferably 30% by weight or less, and particularly preferably 24% by weight or less, from the viewpoint of preventing the heat resistance, the migration characteristics, and the peel force from decreasing.

  The flame retardant resin composition of the first embodiment having such a configuration is excellent in high flame retardancy, compatibility, and molding processability, and further, after curing and molding, adhesion at high temperature, It is a flame retardant resin composition having extremely excellent characteristics.

  The phosphorus-containing polyol used in the flame retardant resin composition of the first embodiment is not particularly limited as long as it is a polyol containing at least one phosphorus atom in the molecule, but contains, for example, phosphorus. Polyester polyol, polyether polyol, polycarbonate polyol, and those in which these components are combined.

  Examples of the phosphorus-containing polyol include a polyol containing a structural unit represented by the following general formula (1) in the main chain of the polyol or the side chain of the polyol.

（Ｒ₁、Ｒ₂、Ｒ₃はハロゲンを含有しない１価または２価の有機残基を表す。）

(R ₁ , R ₂ and R ₃ represent a monovalent or divalent organic residue containing no halogen.)

  Among such phosphorus-containing polyols, those obtained by copolymerizing a phosphorus-containing compound (phosphorus-containing dicarboxylic acid) represented by the following general formula (2) with the polyol are particularly preferable.

（Ｒ₄、Ｒ₅は水素原子、メチル、エチル、プロピル、フェニル等の炭化水素基を示す。Ｒ₄とＲ₅とは同じであってもよいし、また相異なっていてもよい。Ｒ₆、Ｒ₇は水素原子、メチル、エチル、プロピル、ブチル、フェニル、ベンジル、２−ヒドロキシエチル、２−ヒドロキシプロピル、３−ヒドロキシプロピル、４−ヒドソキシブチル、２−ヒドロキシエチルオキシエチル等の炭化水素基またはヒドロキシ基置換炭化水素基等を示す。）

(R ₄ and R ₅ are each a hydrocarbon group such as a hydrogen atom, methyl, ethyl, propyl, or phenyl. R ₄ and R ₅ may be the same or different. R ₆ R ₇ represents a hydrogen atom, a hydrocarbon group such as methyl, ethyl, propyl, butyl, phenyl, benzyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 2-hydroxyethyloxyethyl, or the like; A hydroxy group-substituted hydrocarbon group or the like is shown.)

  The phosphorus content of the phosphorus-containing polyol can be appropriately adjusted as long as it does not deviate from the ratio (0.93% by weight or more) of phosphorus to the thermosetting resin and the curing agent according to the first embodiment. The phosphorus content referred to here is a weight ratio obtained by dividing the atomic weight of phosphorus in the phosphorus-containing polyol molecule (the sum in a plurality of cases) by the molecular weight of the phosphorus-containing polyol.

  The blending amount of the phosphorus-containing polyol in the flame retardant resin composition is preferably 4 to 50 parts by weight, more preferably 6 to 40 parts by weight with respect to 100 parts by weight of the thermosetting resin.

In the flame-retardant resin composition of the first embodiment, a polyol that does not contain phosphorus can be blended together with the phosphorus-containing polyol described above. The polyol that does not contain phosphorus is a polyisocyanate whose total polyol total amount will be described later. Is used in an amount that is approximately equivalent to. Here, an equivalent means the quantity satisfy | filling a following formula.
(Equivalent) = (OH value of polyol) × 7.49 / (NCO (%): isocyanate value)
NCO (%) is also known as an isocyanate value.
Further, as the polyol not containing phosphorus, various polyols such as those of the same type (for example, polyester polyol) and different types of the above-described phosphorus-containing polyol other than the point of not containing phosphorus are used. Also good.

  Moreover, as a polyisocyanate used for the flame retardant resin composition of the first embodiment, as long as it is a polyisocyanate that can react with the phosphorus-containing polyol when heated and cured to form a phosphorus-containing polyurethane in the composition. Although not particularly limited, for example, methylene diisocyanate (MDI), tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI), naphthalene diisocyanate (NDI), xylene diisocyanate (XDI), etc. Polyisocyanate etc. are mentioned. Among these, MDI polyisocyanate is particularly preferable from the viewpoints of heat resistance, flexibility, and reactivity.

  The blending amount of the polyisocyanate in the flame retardant resin composition is preferably 10 to 80 parts by weight, more preferably 20 to 60 parts by weight with respect to 100 parts by weight of the thermosetting resin.

  Examples of the thermosetting resin used in the flame retardant resin composition of the first embodiment include an epoxy resin, a phenol resin, and the like, and particularly when applied to copper or a film as a metal foil. In view of the stability of the semi-cured state (so-called B stage), an epoxy resin is preferable.

  As the epoxy resin, for example, an epoxy resin having at least two epoxy groups in one molecule and containing no halogen is used. Specifically, bisphenol type epoxy resins (for example, bisphenol A type, bisphenol F type, bisphenol S type, etc.), novolac type epoxy resins (for example, phenol novolak type, cresol novolak type, etc.), biphenyl type epoxy resin, naphthalene ring Containing epoxy resin, alicyclic epoxy resin and the like. In particular, bisphenol F-type, bisphenol S-type, and novolak-type epoxy resins are preferred in terms of improving flame retardancy.

  Moreover, as a hardening | curing agent used for 1st Embodiment, what kind of thing may be employ | adopted as long as it is used as a hardening | curing agent of a thermosetting resin, Especially as said thermosetting resin It is preferable to use an epoxy resin in combination with a curing agent used as a curing agent for the epoxy resin.

Specific examples of the curing agent include diaminodiphenylmethane (DDM), diaminodiphenylsulfone (DDS), diaminodiphenyl ether (DDE), imidazoles, hexamethylenediamine, polyamidoamine, dicyandiamide, and phenol novolac.
In particular, amine-based curing agents and phenol-based curing agents are preferable from the viewpoint of reaction stability, and amine-based curing agents are particularly preferable.

The blending amount of the curing agent in the flame retardant resin composition is preferably 1 to 400 parts by weight, more preferably 3 to 300 parts by weight with respect to 100 parts by weight of the thermosetting resin.
Moreover, you may use together a hardening accelerator with this hardening | curing agent as needed.

  Moreover, it is preferable to add a metal-containing flame retardant to the flame retardant resin composition of the first embodiment in terms of improving flame retardancy, workability, and dimensional stability. Here, examples of the metal-containing flame retardant include metal hydrates such as aluminum hydroxide and magnesium hydroxide, metal carbonates such as calcium carbonate, and the like.

  The blending amount of the metal-containing flame retardant in the flame retardant resin composition is preferably 10 to 200 parts by weight, more preferably 20 to 150 parts by weight with respect to 100 parts by weight of the thermosetting resin. When the metal-containing flame retardant is within this range, the electrical characteristics are improved, the adhesion is improved, the filling between the circuits is suppressed when used for the coverlay, and the flame resistance is improved (respectively confirmed by experiments). Is preferred.

  Moreover, in the flame retardant resin composition of the first embodiment, various additives such as other synthetic resins and additives (in addition to the above-described components as necessary) within a range in which various properties are not deteriorated. For example, a polyester resin, an antioxidant, a surfactant, a coupling agent, etc.) may be added.

  The flame retardant resin composition of the first embodiment preferably has a glass transition temperature (TG) of 100 ° C. or higher in terms of improving heat resistance and flexibility.

  The flame retardant resin composition of the first embodiment is used after being cured upon its use (especially for use in the above application). In particular, the flame retardant resin composition of the first embodiment is preferably used after being cured under predetermined conditions such as heating and pressurization.

  As predetermined conditions in this case, the temperature is preferably 140 to 200 ° C., the pressure is preferably 2 to 5 MPa, and the time is preferably 10 to 60 minutes.

( Reference Example: Flame Retardant Resin Composition of Second Embodiment)
As a flame retardant resin composition, as a second embodiment which is a reference example, a flame retardant resin composition comprising a thermosetting resin, a curing agent, and a phosphorus-containing polyurethane resin, Provided is a flame retardant resin composition characterized in that phosphorus in a phosphorus-containing polyurethane resin is contained in a ratio of 0.96% by weight or more with respect to the total amount of the thermosetting resin and the curing agent. The

  In addition, about the flame retardant resin composition of 2nd Embodiment, it replaces with a phosphorus containing polyol and polyisocyanate, and the point which mix | blends a phosphorus containing polyurethane resin is mentioned above, The flame retardant resin composition of 1st Embodiment mentioned above. It is the same thing as a thing. Therefore, the matters described in the first embodiment described above are appropriately applied to points that are not particularly described in detail regarding the second embodiment.

  In the flame-retardant resin composition of the second embodiment, the phosphorus-containing polyurethane resin that is one of the blending components is decomposed into a phosphorus-containing polyol and a polyisocyanate by heat during combustion, and the flame-retardant effect and foaming effect due to phosphorus. It is estimated that it exhibits a high flame retardant effect.

In the flexible printed wiring board using the flame retardant resin composition of the second embodiment as an adhesive, the phosphorus-containing polyurethane resin in the flame retardant resin composition acts in the same manner as in the first embodiment. It is presumed that the bending property is remarkably improved.
The phosphorus in the phosphorus-containing polyurethane resin is contained in a ratio of 0.96% by weight or more with respect to the total amount of the thermosetting resin and the curing agent.

  In particular, the phosphorus content needs to be 0.96% by weight or more from the viewpoint of exhibiting electrical properties such as glass transition temperature and migration of the composition after curing, adhesion, and flame retardancy.

On the other hand, the phosphorus content is preferably 30% by weight or less, and particularly preferably 24% by weight or less, from the viewpoint of preventing the heat resistance, the migration characteristics, and the peel force from decreasing.
The flame retardant resin composition of the second embodiment having such a configuration is excellent in high flame retardancy, compatibility, and molding processability, and further after bending and bending at high temperatures and adhesion. It is a flame retardant resin composition having excellent properties and electrical characteristics.

  The phosphorus-containing polyurethane resin used in the flame retardant resin composition of the second embodiment is not particularly limited as long as it is a polyurethane resin containing at least one phosphorus atom in the molecule, and contains various phosphorus. Polyurethane resins can be used.

  As a phosphorus containing polyurethane resin, the polyurethane resin etc. which contain the structural unit represented by following General formula (1) in a polymer principal chain or a polymer side chain are mentioned, for example.

（Ｒ₁、Ｒ₂、Ｒ₃はハロゲンを含有しない１価または２価の有機残基を表す。）

(R ₁ , R ₂ and R ₃ represent a monovalent or divalent organic residue containing no halogen.)

  Among such phosphorus-containing polyurethane resins, those obtained by copolymerizing a polyurethane resin with a phosphorus-containing compound (phosphorus-containing dicarboxylic acid) represented by the following general formula (2) are particularly preferable.

（Ｒ₄、Ｒ₅は水素原子、メチル、エチル、プロピル、フェニル等の炭化水素基を示す。Ｒ₄とＲ₅とは同じであってもよいし、また相異なっていてもよい。Ｒ₆、Ｒ₇は水素原子、メチル、エチル、プロピル、ブチル、フェニル、ベンジル、２−ヒドロキシエチル、２−ヒドロキシプロピル、３−ヒドロキシプロピル、４−ヒドソキシブチル、２−ヒドロキシエチルオキシエチル等の炭化水素基またはヒドロキシ基置換炭化水素基等を示す。）
尚、これらの一般式（１）及び（２）の構造は、前述した第１実施形態で用いられるリン含有ポリオールの例及び好適態様に含まれる構造と同じである。

(R ₄ and R ₅ are each a hydrocarbon group such as a hydrogen atom, methyl, ethyl, propyl, or phenyl. R ₄ and R ₅ may be the same or different. R ₆ R ₇ represents a hydrogen atom, a hydrocarbon group such as methyl, ethyl, propyl, butyl, phenyl, benzyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 4-hydroxybutyl, 2-hydroxyethyloxyethyl, or the like; A hydroxy group-substituted hydrocarbon group or the like is shown.)
In addition, the structure of these general formula (1) and (2) is the same as the structure contained in the example and suitable aspect of the phosphorus containing polyol used in 1st Embodiment mentioned above.

  Examples of the polyol component as a raw material for the phosphorus-containing polyurethane resin include the polyol used in the first embodiment described above, that is, a polyester polyol, a polyether polyol, a polycarbonate polyol, and a combination of these components.

  In addition, as an isocyanate component as a raw material of the phosphorus-containing polyurethane resin, the polyisocyanate used in the above-described first embodiment, that is, methylene diisocyanate (MDI), tolylene diisocyanate (TDI), hexamethylene diisocyanate (HDI). ), Naphthalene diisocyanate (NDI), xylene diisocyanate (XDI) and other polyisocyanates. Among these, MDI polyisocyanate is particularly preferable from the viewpoints of heat resistance, flexibility, and reactivity.

Moreover, as a chain extender used for preparation of phosphorus-containing polyurethane resin, glycol components such as ethylene glycol and propylene glycol are mainly used.
Moreover, as a phosphorus containing polyurethane resin, a commercial item can also be used, for example, brand name "UR-2400" (made by Toyobo Co., Ltd.) etc. are mentioned.

  The phosphorus content of the phosphorus-containing polyurethane resin can be appropriately adjusted as long as it does not deviate from the ratio (0.96% by weight or more) of phosphorus to the thermosetting resin and the curing agent according to the second embodiment. The phosphorus content referred to here is a weight ratio obtained by dividing the atomic weight of phosphorus in the phosphorus-containing polyol molecule (the sum in a plurality of cases) by the molecular weight of the phosphorus-containing polyol.

  The compounding amount of the phosphorus-containing polyurethane resin in the flame retardant resin composition is preferably 20 to 70 parts by weight, more preferably 30 to 60 parts by weight with respect to 100 parts by weight of the thermosetting resin.

In the flame-retardant resin composition of the second embodiment, a polyurethane resin not containing phosphorus can be blended together with the phosphorus-containing polyurethane resin described above, and the polyurethane resin not containing phosphorus is the total amount of all polyurethane resins. Is 100 parts by weight of thermosetting resin,
It is used in an amount of 0 to 40 parts by weight. Moreover, as polyurethane resin which does not contain phosphorus, commercial items, such as brand name "UR-5537", "UR-3500" (made by Toyobo Co., Ltd.), Desmoban 588, Desmoban 786 (made by DIC Bayer Polymer Co., Ltd.), are used, for example. be able to.

  Regarding the thermosetting resin and curing agent used in the flame retardant resin composition of the second embodiment, and the metal-containing flame retardant and various additives used as necessary, the flame retardant resin of the first embodiment described above. The same as that used in the composition.

  Further, the TG of the flame retardant resin composition of the second embodiment and the predetermined conditions such as heating and pressurization when it is cured when necessary are the same as those of the first embodiment described above. .

  Although not particularly used in the flame retardant resin composition of the first and second embodiments described above, the flame retardant resin composition of the present invention includes a thermosetting resin and other components in addition to heat. A plastic resin may also be included. Examples of the thermoplastic resin include polyester resin, polystyrene resin, polymer epoxy resin (typically, phenoxy resin, etc.), polyethersulfone resin (PES), polysulfone resin (PS), polyamide resin (PA), and the like. .

(Metal-clad laminate for flexible printed wiring boards)
As shown in FIG. 2, the metal-clad laminate for flexible printed wiring board of the present invention is a laminate 20 in which a film 2 and a metal foil 3 are laminated, and the flame-retardant resin composition 1 described above is It is used as an adhesive for adhering the film 2 and the metal foil 3. FIG. 2 is a schematic sectional view showing an embodiment 20 (single-sided metal-clad laminate) of a metal-clad laminate according to the present invention. The metal-clad laminate of the present invention corresponds to a substrate when used for a flexible printed wiring board.

  In the metal-clad laminate of the present invention, it is preferable that the thickness of the film is 4 to 75 μm and the thickness of the layer made of the flame retardant resin composition as an adhesive is 5 to 30 μm.

  Moreover, as another embodiment, the metal-clad laminate of the present invention is a laminate 21 in which a pair of metal foils 3 and 3 are laminated on both surfaces of a film 2 as shown in FIG. Examples include those in which the flammable resin compositions 1 and 1 are used as adhesives for adhering the film 2 and the metal foils 3 and 3 on both sides, respectively. FIG. 3 is a schematic sectional view showing another embodiment 21 (double-sided metal-clad laminate) of the metal-clad laminate according to the present invention.

  As a film used here, a polyimide film, a polyester film, a polyamide film etc. are employ | adopted, for example, A polyimide film is preferable at points, such as a flame retardance, electrical insulation, heat resistance, and an elasticity modulus. In addition, you may employ | adopt the film of another raw material.

  In addition, as the metal foil, for example, a current-carrying material such as copper foil or silver foil is employed.

  In the metal-clad laminates 20 and 21 shown in FIGS. 2 and 3, a polyimide film is used as the film 2, and a copper foil is used as the metal foil 3.

(Coverlay)
As shown in FIG. 1, the coverlay of the present invention is such that the above-mentioned heat-resistant resin composition 1 is provided on a synthetic resin film 2 having electrical insulation. FIG. 1 is a schematic sectional view showing an embodiment 10 of a cover lay according to the present invention.

  As a coverlay of this invention, the thing of the structure etc. which apply | coated the above-mentioned heat-resistant resin composition in the laminated state to the synthetic resin film which has electrical insulation, etc. are mentioned, for example. Such a coverlay is used to be provided for protecting the circuit such as a metal-clad laminate for a flexible printed wiring board provided with a circuit.

  In the cover lay of this embodiment, it is preferable that the synthetic resin film has a thickness of 4 to 75 μm and the layer made of the flame retardant resin composition has a thickness of 5 to 45 μm.

  As said synthetic resin film, a polyimide film, a polyester film, a polyamide film etc. are employ | adopted, for example, A polyimide film is preferable at points, such as a flame retardance, electrical insulation, heat resistance, and an elasticity modulus. In addition, you may employ | adopt the film of another raw material. In addition, the film can be stably stored by impregnating or applying a thermosetting resin (a mixture of an epoxy resin, a BT resin, etc. with a curing agent, a solvent, a filler, an additive, etc.) and drying by heating. It can also be used as a prepreg in a state where the curing has progressed to some extent.

  In the coverlay 10 shown in FIG. 1, a polyimide film is used as the film 2, and the flame retardant resin composition 1 provided on the film 2 functions as an adhesive. The adhesive used here may be the same as or different from the adhesive used for the metal-clad laminate described above.

(Adhesive sheet for flexible printed wiring boards)
The adhesive sheet for flexible printed wiring boards of this invention consists of a flame-retardant resin composition mentioned above, and is a sheet-like thing.

The thickness of the adhesive sheet of the present invention is preferably in the range of 10 to 60 μm.
The adhesive sheet of the present invention is used as a sheet that can be stuck when bonding metal foils, films, a composite containing glass fibers and metal foil, and the composite and film.

(Flexible printed wiring board)
As shown in FIG. 5, the flexible printed wiring board of the present invention is formed by forming a cover lay 10 with the flame retardant resin composition 1 described above, and the cover lay 10 is provided on the metal foil 3. . FIG. 5 is a schematic sectional view showing one embodiment 30 (single-sided board) of the flexible printed wiring board according to the present invention.

  As for the flexible printed wiring board of this invention, it is possible to set the thickness (whole) arbitrarily according to a use.

  Examples of the flexible printed wiring board of the present invention include those having a structure in which a coverlay is provided on a necessary portion of a metal-clad laminate for a flexible printed wiring board provided with a circuit. Specifically, as shown in FIG. 5, for example, a single-sided metal-clad laminate 20 composed of a film 2, a metal foil 3 and a flame-retardant resin composition 1 as an adhesive is used as a substrate of a wiring board, and the laminate A desired circuit is drawn by performing an etching process on the 20 metal foils 3, and then a coverlay 10 made of the film 2 and the flame retardant resin composition 1 as an adhesive on the metal foil 3 as the circuit. Is a flexible printed wiring board 30 obtained by laminating the metal foil 3 so as to be in contact with the surface of the adhesive.

  Moreover, as shown in FIG. 4, the flexible printed wiring board of this invention is a double-sided metal comprising a film 2, metal foils 3, 3 and a flame retardant resin composition 1, 1 as an adhesive. Using the tension laminate 21 as a substrate of the wiring board, a desired circuit is drawn by etching the metal foils 3, 3 of the laminate 21, and then on the metal foils 3, 3 as the circuit, A flexible print obtained by laminating a pair of coverlays 10 and 10 comprising a film 2 and a flame retardant resin composition 1 as an adhesive so that the metal foils 3 and 3 are in contact with the adhesive surface from both sides. An example of the wiring board 31 is given. FIG. 4 is a schematic sectional view showing another embodiment 31 (double-sided board) of the flexible printed wiring board according to the present invention.

The flexible printed wiring board of the present invention has a preferred embodiment in which the metal-clad laminate for flexible printed wiring board and the coverlay are bonded together by hot pressing.
Here, as conditions for hot pressing, it is preferable that the temperature is 140 to 200 ° C., the pressure is 2 to 5 MPa, and the time is 10 to 60 minutes.

  The flexible printed wiring board of the present invention is suitably applied as a so-called chip-on-flex flexible printed wiring board for mounting an IC chip, for example.

In the flexible printed wiring boards 30 and 31 shown in FIGS. 5 and 4, a polyimide film is used as the film 2, and a copper foil is used as the metal foil 3 as a circuit. Moreover, the flame retardant resin compositions 1a and 1b are used for the adhesive in the printed wiring boards 30 and 31, and these may have the same or different blending composition.
The flexible printed wiring board of the present invention is not limited to such an embodiment, and may be a multilayer printed wiring board in which several layers having the above-described configuration are laminated.

  Hereinafter, the present invention will be described more specifically with reference to examples and test examples of the present invention. However, the present invention is not limited to the examples.

(Examples 1-5 and Comparative Examples 1-3)
The formulations shown in Table 1 were prepared.

( Examples 6 to 10 (Reference Examples 1 to 5 according to the second embodiment ) and Comparative Examples 4 to 6)
Except having replaced with the mixing | blending shown in Table 2, each compounding was obtained like the said Examples 1-5.

The details of each component in Tables 1 and 2 are as follows.
Epoxy resin A: A bisphenol type epoxy resin having an epoxy equivalent number of 170.
Epoxy resin B: A novolac type epoxy resin having an epoxy equivalent number of 176.
Amine curing agent: diaminodiphenylmethane (DDM).
Phenol curing agent: phenol novolac resin having an OH value of 110.
Phosphorus-containing polyol: A polyester polyol having an OH value of 350 (phosphorus content: 14% by weight).
Polyol: A polyester polyol having an OH value of 350.
Polyisocyanate: MDI polyisocyanate having an NCO value of 25%.
Phosphorus-containing polyurethane: “UR-2400” (phosphorus content 4% by weight) manufactured by Toyobo Co., Ltd.
Polyurethane: “UR-5537” manufactured by Toyobo Co., Ltd.
* Note) Phosphorus content: Ratio of phosphorus in the phosphorus-containing polyol or phosphorus-containing polyurethane resin to the total amount of thermosetting resin and curing agent (weight basis)

The following evaluation tests were performed on each prepared resin composition under the following heat curing conditions.
Heating temperature: 140 to 180 ° C. Pressurization: 2-5 MPa Time: 30-60 minutes

<TG>
A semi-cured resin plate is prepared from each resin composition prepared by blending so as to have a thickness that can be measured by a DMA method (dynamic viscoelasticity analysis method), and a glass transition temperature (TG) (° C. ) Was measured.

<Flammability>
For each resin composition (semi-cured state: B stage and fully cured state: C stage), flame retardancy was evaluated by whether or not the UL94 standard V-0 grade could be achieved according to the following criteria.
A: UL94 standard V-0 grade can be achieved perfectly.
○: UL94 standard V-0 grade can be almost achieved, and there is no practical problem.
X: The UL94 standard V-0 grade cannot be achieved and is not practical.

<Stripping force>
By measuring the peeling force for each resin composition (fully cured state: C stage), the adhesive force was evaluated in accordance with the following criteria (peeling force: 4 N / cm or more passed). The peeling force was measured in accordance with JPCA BM-02 (180 ° film drawing).
A: The peeling force is 10 N / cm or more, and has an adhesive force that causes no problem in practical use.
○: Peeling force is 4 N / cm or more and less than 10 N / cm, and has a practical adhesive force.
X: The peeling force is less than 4 N / cm, and the adhesive force is insufficient.

<Migration>
Each of the double-sided copper-clad laminate and the single-sided copper-clad laminate (see FIG. 8) was subjected to a predetermined treatment to prepare a circuit pattern shown in FIG. In addition, the resin composition prepared by blending is applied to the substrate by a coating method such as a bar coater method, a comma coater method, a die coater method, or a gravure coater method so that the coating thickness after heating and drying is 20 μm. A cover lay in a semi-cured state (so-called B stage state) was prepared. The coverlay was laminated on the circuit pattern of the laminated board, and heated and pressurized by hot press to produce a printed wiring board. This printed wiring board was tested under predetermined conditions (voltage: 100 V, temperature: 85 ° C., humidity: 85% RH), and a change in voltage was observed for a predetermined time (1000 hours). At this time, migration was evaluated according to the following criteria.
A: The resistance value was 1.0 × 10 ¹⁰ or more and had excellent migration properties.
A: The resistance value was 1.0 × 10 ⁷ or more, and there was no practical problem.
X: The resistance value cannot reach 1.0 × 10 ⁷ and is not practical.

In addition, the detail about preparation and evaluation method of the test piece of a printed wiring board is as showing next.
(Production and evaluation method for test pieces of printed wiring board)
As for the migration property, the following d was experimentally evaluated for those subjected to the treatments from a to c below.
a Each resin composition was applied to a polyimide film (Kanebuchi Chemical Industry Co., Ltd., Apical 25NPI) to a thickness of 10 μm using a bar coater, and heated and dried at 150 ° C. for 5 minutes to form a B stage. Then, the roughened surface of the electrolytic copper foil (Mitsui Metal Mining Co., Ltd., 3EC-3, 18 μm) is bonded to the resin composition surface with a laminator to obtain a single-sided plate.
b Further, each resin composition is applied to the polyimide film surface of the single-sided plate by a bar coater so as to have a thickness of 10 μm (the same resin composition is applied to both surfaces of the polyimide film), and 5 at 150 ° C. After heat-drying for a minute, the roughened surface of electrolytic copper foil (Mitsui Metal Mining Co., Ltd. 3EC-3 18 micrometers) is bonded to the resin composition surface with a laminator to obtain a double-sided plate.
c This double-sided plate was cured by heating at 160 ° C. for 5 hours, and then a comb-shaped pattern of L / S (line / space) = 100/100 was formed on one side, and a coverlay (polyimide film (bell) was formed thereon. Each resin composition (adhesive) is coated on Sakai Chemical Industry Co., Ltd. (Apical 25 NPI) and dried to a thickness of 25 μm) and dried at 180 ° C. × 2.94 MPa × 30 minutes. The test piece is hot-pressed and bonded under the conditions described above.
d DC100V is applied to the test piece in an atmosphere of 85 ° C. and 85% (Rh) and held for 1000 hours. Thereafter, the resistance value is confirmed.

  Migration (also referred to as copper migration) means that when a voltage is applied between copper foil circuits, copper ions are eluted from the anode using ionic impurities in the adhesive as a medium, and copper is deposited on the cathode side. As a matter of fact, when this copper deposition becomes severe, the copper deposited between the circuits grows like a tree branch. This is called a tree, and when a tree is generated, the resistance value between the circuits is lowered and insulation cannot be maintained.

  From the experimental results of each of the above examples, the flame-retardant resin composition of the present invention is excellent in compatibility before curing and molding processability, for example, adhesiveness after curing and molding as an adhesive for printed wiring boards, printed wiring It was confirmed that the electrical characteristics of the plate were also excellent.

FIG. 1 is a schematic sectional view showing an embodiment of a cover lay according to the present invention. FIG. 2 is a schematic sectional view showing an embodiment (single-sided metal-clad laminate) of a metal-clad laminate according to the present invention. FIG. 3 is a schematic cross-sectional view showing another embodiment (double-sided metal-clad laminate) of the metal-clad laminate according to the present invention. FIG. 4 is a schematic cross-sectional view showing an embodiment (double-sided board) of a flexible printed wiring board according to the present invention. FIG. 5: is a schematic sectional drawing which shows another embodiment (single-sided board) of the flexible printed wiring board based on this invention. FIG. 6 is a schematic cross-sectional view showing an example of a flex-rigid printed wiring board to which the flame retardant resin composition according to the present invention can be applied. FIG. 7 is an explanatory view (plan view) showing a circuit pattern used in a characteristic evaluation test of a printed wiring board using the flame retardant resin composition according to the present invention. FIG. 8 is a schematic cross-sectional view showing a laminated board provided with a copper foil before the circuit pattern shown in FIG. 7 is formed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1a, 1b ... Flame retardant resin composition, 2 ... Film, 3 ... Metal foil, 10 ... Coverlay, 20, 21 ... Metal-clad laminate, 30, 31 ... Flexible printed wiring board, 40 ... Flex-rigid print Wiring board, 41 ... Copper-clad laminate, 42, 47 ... Circuit, 43 ... Coverlay, 44 ... FPC, 45 ... Adhesive sheet, 46 ... Rigid substrate, 48 ... Through hole

Claims (7)

A flame retardant resin composition to be bonded to a composite made of glass fibers in the field of electronic materials, a film, and a metal foil,
Thermosetting resin, curing agent, phosphorus-containing polyol, polyisocyanate, and metal-containing flame retardant are blended,
The phosphorus in the phosphorus-containing polyol is contained in a ratio of 0.93% by weight or more with respect to the total amount of the thermosetting resin and the curing agent ,
The amount of the phosphorus-containing polyol is 4 to 50 parts by weight with respect to 100 parts by weight of the thermosetting resin,
The blending amount of the polyisocyanate is 10 to 80 parts by weight with respect to 100 parts by weight of the thermosetting resin,
The amount of the metal-containing flame retardant is 10 to 200 parts by weight with respect to 100 parts by weight of the thermosetting resin,
A flame-retardant resin composition in which the phosphorous-containing polyol and the polyisocyanate are reacted by being applied to a composite made of glass fibers, a film, and a metal foil in the electronic material field, and heated .   The flame retardant resin composition according to claim 1, wherein the thermosetting resin is an epoxy resin.   The flame retardant resin composition of Claim 1 or 2 whose glass transition temperature is 100 degreeC or more. A metal-clad laminate for a flexible printed wiring board, wherein the flame-retardant resin composition according to any one of claims 1 to 3 is used as an adhesive for adhering a film and a metal foil. A coverlay, wherein the flame retardant resin composition according to any one of claims 1 to 3 is provided on a synthetic resin film having electrical insulation. It consists of a flame-retardant resin composition in any one of Claims 1-3 , The adhesive sheet for flexible printed wiring boards characterized by the above-mentioned. The flexible printed wiring board characterized by forming a coverlay with the flame-retardant resin composition in any one of Claims 1-3 , and this coverlay is provided on metal foil.

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