JP2009144052A - Resin composition for printed circuit board, insulating layer with supporting substrate, laminate, and printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for a printed circuit board which is used for a flexible printed circuit board with both high flexibility and folding resistance (flexible property), and to provide an insulating material with a supporting substrate and a metal-clad laminate. <P>SOLUTION: This resin composition for the printed circuit board which is used for the flexible printed circuit board comprises a flexible epoxy resin with a flexible structure (a), an epoxy resin with ≥2 epoxy groups (b), an amine curing agent (c), and a curing agent with an ester group (d), wherein the curing agent with the ester group is an aromatic ester compound produced by a condensation reaction of a polyvalent aromatic carboxylic acid with polyhydric phenol. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin composition for printed circuit boards, an insulating layer with a supporting substrate, a laminated board, and a printed circuit board.

  Because flexible printed circuit boards are thin, light, and have excellent flexibility, they are used mainly in mobile devices such as mobile phones, PDAs, and liquid crystal driver modules. Recently, these electronic devices have become more sophisticated and smaller in size. With the trend toward miniaturization, miniaturization of wiring on flexible printed circuit boards, high-density mounting, bending resistance, and the like are increasingly required.

For example, a flexible printed circuit board used in a foldable mobile phone has a hinge portion that is always bent, and high flexibility is required.
On the other hand, there is a demand for folding the flexible printed circuit board into the housing for the housing portion other than the hinge portion, and the folding property (folding resistance) is required.
Also, a flexible printed circuit board for optical pickup is bent and arranged in a narrow space. If the warpage is large, the base materials may rub against each other during sliding to cause poor conduction, so low warpage is required.

  In addition, as the functionality of small digital devices increases, the flexible printed circuit boards used for them will change from single-sided or double-sided boards to multi-layer boards, or adhere to electromagnetic shielding materials or reinforcing boards, increasing the number of mounting parts. Therefore, in order to repeatedly mount a heat history and receive a heat history, adhesion after a plurality of heat histories is required.

Also, due to environmental concerns, there is a demand for mounting using lead-free solder, and solder reflow temperature (260 ° C)
Therefore, high adhesion, high heat resistance, and high dimensional stability that can withstand the environment are required.

  Furthermore, it is required that the flame retardant does not contain halogen. Until now, brominated epoxy resins have generally been used as flame retardants (for example, Patent Document 1). However, since there is concern about the generation of dioxins during combustion, halogen-free materials are required.

In this way, both conflicting properties of flexibility (resin hardness) and folding resistance (resin softness, flexibility), heat resistance (solder heat resistance after moisture absorption), low warpage, heat resistance history Although there is a demand for a flexible printed circuit board having all of various characteristics such as stability, dimensional stability, and halogen-free, there is actually no flexible printed circuit board having all the characteristics.
As described above, the flexible printed circuit board has been described. However, the invention is not limited to the flexible printed circuit board. For example, a laminated board obtained by laminating an ultrathin prepreg obtained by impregnating an ultrathin glass woven fabric with resin is folded and stored. There has been the same problem that a circuit board using a laminated board having various properties such as properties, heat resistance, heat history resistance, and dimensional stability is required.
JP-A-4-197746

  The present invention has been made in view of the above circumstances, and has a resin composition for a printed circuit board that has both high flexibility and folding resistance (flexibility), an insulating layer with a supporting substrate, a laminated board, and a printed circuit. To provide a board.

  According to the present invention, a resin composition for a printed circuit board used for a flexible printed circuit board, which is a flexible epoxy resin having a flexible structure, and an epoxy resin having two or more epoxy groups in one molecule; A printed circuit board resin composition comprising an amine-based curing agent and a curing agent having an (active) ester group is provided.

  Furthermore, the insulating layer with a supporting base material in which the insulating layer made of the resin composition is formed on at least one surface side of the supporting base material made of metal foil or resin film can be provided.

  Moreover, it is good also as a laminated board by which the metal foil was laminated | stacked through the insulating layer which consists of a resin composition for printed circuit boards on the at least one surface side of the support base material which consists of the said resin film, and also the said lamination | stacking A conductive circuit is formed by etching the metal foil of the board, and is laminated so as to cover the conductive circuit via an insulating layer made of a resin composition for printed circuit boards on one surface side of the support base made of the resin film. A printed circuit board may be used.

  ADVANTAGE OF THE INVENTION According to this invention, the resin composition for printed circuit boards which has both high flexibility and folding resistance (flexibility), the insulating layer with a support base material, a laminated board, and a printed circuit board can be provided.

  Hereinafter, the resin composition for a printed circuit board, the insulating layer with a supporting substrate, the laminate and the printed circuit board of the present invention will be described in detail.

  The resin composition for circuit boards of the present invention can be used as a coverlay film in which an insulating layer is formed on one side of a resin film such as a polyimide film as a supporting substrate, or a resin composition for circuit boards on one or both sides of the resin film. It can be used as a laminated board for flexible printed circuit boards by forming an insulating layer and laminating and bonding to a metal foil. Moreover, it can be set as a printed circuit board by giving a circuit process.

  The resin composition for a printed circuit board of the present invention comprises a flexible epoxy resin (a) having a flexible structure, an epoxy resin (b) having two or more epoxy groups in one molecule, and an amine curing agent. (C) and the curing agent (d) having an ester group are included.

  Hereinafter, each component which comprises the resin composition for printed circuit boards of this invention is demonstrated.

  The resin composition for printed circuit boards of this invention contains the flexible epoxy resin which has a flexible structure. By introducing a flexible skeleton into an epoxy resin, the effect of flexibility and low warpage is superior to that of a general epoxy resin known so far. By introducing a flexible structure, it is possible to overcome the drawbacks of a hard and brittle epoxy resin, reduce a large internal stress during curing, and suppress warping of the cured product. In order to cause a crosslinking reaction, it is preferable that the molecule has two or more epoxy groups and the epoxy equivalent is 400 or more and 1200 or less. Although content of the flexible epoxy resin which has a softness | flexibility is not specifically limited, 5 to 40 weight% of the whole resin composition is preferable, and 10 to 30 weight% is more preferable. When the content is 5% by weight or more and 40% by weight or less, sufficient flexibility and low warpage are obtained. When the content is 10% by weight or more and 20% by weight or less, heat resistance and adhesion are provided while providing flexibility. Excellent sex effect.

本発明に係るプリント回路板用樹脂組成物は、１分子中に２個以上のエポキシ基を有するエポキシ樹脂を含む。架橋反応をおこすために分子中に少なくとも２個以上のエポキシ基を有するものであれば、どの様なエポキシ樹脂でもよく、例えば、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、ビスフェノールＳ型エポキシ樹脂、ビフェニル型エポキシ樹脂、脂環式エポキシ樹脂、ノボラック型エポキシ樹脂、クレゾール型エポキシ樹脂等が挙げられる。これらの樹脂は、各々単独で使用し得られるほか、必要により数種類の任意の組合せで併用しても構わない。
特に、ビスフェノールＡ型エポキシ樹脂は分子構造の水酸基による分子間結合で密着性に優れている。ビスフェノールＡ型エポキシ樹脂の含有量は、特に限定されないが、樹脂組成物全体の１０重量％以上、３０重量％以下が好ましく、１５重量％以上、２５重量％以下がより好ましい。１０重量％以上では得られた硬化物の密着性が良好である。３０重量％以下ではエポキシ樹脂の反応性が高まるので、成形時の接着剤の染み出しが少なくすることができる。また、硬化剤との相溶性に優れる。
ビスフェノールＡ型エポキシ樹脂としては、特に限定はされないが、低粘度であるものが好ましく、さらに耐熱性を有していればより好ましい。 As the flexible epoxy resin (a) having a flexible structure, a flexible epoxy resin represented by the following general formula (1) is preferable.

The resin composition for printed circuit boards according to the present invention contains an epoxy resin having two or more epoxy groups in one molecule. Any epoxy resin may be used as long as it has at least two epoxy groups in the molecule for causing a crosslinking reaction. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin , Biphenyl type epoxy resin, alicyclic epoxy resin, novolac type epoxy resin, cresol type epoxy resin and the like. These resins can be used alone or in combination of several kinds as required.
In particular, the bisphenol A type epoxy resin is excellent in adhesion due to intermolecular bonding due to hydroxyl groups in the molecular structure. The content of the bisphenol A type epoxy resin is not particularly limited, but is preferably 10% by weight or more and 30% by weight or less, and more preferably 15% by weight or more and 25% by weight or less of the entire resin composition. If it is 10% by weight or more, the obtained cured product has good adhesion. When the content is 30% by weight or less, the reactivity of the epoxy resin is increased, so that bleeding of the adhesive during molding can be reduced. Moreover, it is excellent in compatibility with the curing agent.
The bisphenol A type epoxy resin is not particularly limited, but preferably has a low viscosity, and more preferably has heat resistance.

  The curing agent includes an amine compound that cures the epoxy resin and a curing agent having an ester group. Examples of the amine curing agent include diaminodiphenylmethane, metaphenylenediamine, diaminodiphenylsulfone, isophoronediamine, norbornenediamine, and the like. Of these, diaminodiphenyl sulfone is preferably used. Although not particularly limited, 5% by weight or more and 20% by weight or less of the total resin composition is preferable, and 8% by weight or more and 17% by weight or less is more preferable. If it is less than the said lower limit, wettability with a to-be-adhered body may worsen, and adhesiveness may fall. If the above upper limit is exceeded, the curing agent that does not contribute to the reaction remains, so that bleeding may increase.

このように、下記式（２）で表される構造では、エステル基が芳香族環に挟まれたかたちとなり、剛直であるとともに、耐熱性に優れ、かつ、繰り返し熱履歴を受けるため複数回の耐熱履歴性が向上する。Ａｒ_１、Ａｒ_２はそれぞれ独立に芳香族環を示す。芳香族環としては、例えば、ベンゼン、ナフタレン環等のＣ６−２０芳香族環が挙げられる。なお、芳香族環は、置換基として、例えば、ヒドロキシル、メチル、エチル、プロピル、イソプロピル、ブチル、イソブチル、ｓ−ブチル、ｔ−ブチル基等のアルキル基；メトキシル、エトキシル、プロポキシル基等のアルコキシル基等を有していてもよい。 The ester group is obtained by a condensation reaction between a carboxylic acid compound and phenol, but the reactive ester group used in the present invention is an aromatic composed of a condensation reaction between a polyvalent aromatic carboxylic acid and a polyhydric phenol so that it can be crosslinked upon curing. An ester compound is preferred. For example, polyaromatic carboxylic acids such as isophthalic acid, terephthalic acid, 1,4-, 2,3- or 2,6-naphthalenedicarboxylic acid, a mixture of isophthalic acid and terephthalic acid, and dicyclopentadienyl diphenol Aromatic ester compounds composed of polyhydric phenols. For example, an aromatic ester compound including a structure represented by the following formula (2) is preferable.

In this way, in the structure represented by the following formula (2), the ester group is in the form of being sandwiched between aromatic rings, is rigid, has excellent heat resistance, and is repeatedly subjected to thermal history, so that it can be repeated multiple times. Improved heat resistance history. Ar ₁ and Ar ₂ each independently represent an aromatic ring. Examples of the aromatic ring include C6-20 aromatic rings such as benzene and naphthalene rings. The aromatic ring is substituted with, for example, an alkyl group such as hydroxyl, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, or t-butyl group; an alkoxyl such as methoxyl, ethoxyl, or propoxyl group. It may have a group or the like.

The ester equivalent of the curing agent having an ester group to be used is preferably 100 or more and 500 or less. If the equivalent weight is within this range, heat resistance and flexibility will be obtained, and adhesion will be good. Although content of the hardening | curing agent which has ester group is not specifically limited, 3 weight% or more and 16 weight% or less of the whole resin composition are preferable, and 5 weight% or more and 14 weight% or less are more preferable. Since the curing agent that does not contribute to the reaction does not remain above the lower limit value, the resin oozes out during molding, and the cured product obtained is excellent in flexibility below the upper limit value.
The curing agent having an ester group exhibits a high reaction activity with respect to the epoxy group, and does not produce a highly polar hydroxyl group in the cured product by the curing reaction with the epoxy resin as represented by the following formula (3). It is preferable that low water absorption, moisture resistance, and moisture absorption solder heat resistance are achieved. Moreover, since the cured product is a curing system that does not produce a highly polar hydroxyl group, a cured product having a low dielectric loss tangent can be obtained.

Since the curing agent having an ester group has a large number of ester groups in one molecule, the cured product has a high crosslinking density and excellent heat resistance. The general formula (3) may have a plurality of bulky alicyclic structures in the molecular skeleton, thereby suppressing aggregation of molecular chains, and is excellent in compatibility with the epoxy resin. It is excellent in solubility with an organic solvent when adjusting the varnish, and has good workability.
The ester group is obtained by a condensation reaction between a carboxylic acid compound and phenol, but in particular, the reactive ester group used in the present invention is an aromatic composed of a condensation reaction of a polyvalent aromatic carboxylic acid and a polyhydric phenol so that it can be crosslinked upon curing. Preferred are ester compounds such as isophthalic acid, terephthalic acid, 1,4-, 2,3-, or 2,6-naphthalenedicarboxylic acid, a mixture of isophthalic acid and terephthalic acid, and dicyclohexane. Aromatic ester compounds composed of polyhydric phenols such as pentadienyl diphenol can be mentioned.

  The amount of the curing agent is preferably in the range of 0.8 to 1.2 in terms of the equivalent ratio of the curing agent to the epoxy equivalent 1 of the epoxy resin. More preferably, the equivalent ratio of the curing agent to the epoxy equivalent 1 of the epoxy resin is 0.9 or more and 1.1 or less. When the equivalent ratio of the curing agent is in the range of 0.8 to 1.2, the wettability and adhesion to the adherend are excellent. Further, the bleeding of the adhesive can be reduced.

  It is preferable that the equivalent ratio of the flexible epoxy resin having the flexible structure and the epoxy resin having two or more epoxy groups in one molecule is in a range of 0.1 or more and 1.0 or less. Within this range, low warpage, flexibility, adhesion, and heat resistance can be obtained without lowering the glass transition temperature. Moreover, it is more preferable that the equivalent ratio of the flexible epoxy resin having a flexible structure and the epoxy resin having two or more epoxy groups in one molecule is 0.4 or more and 0.8 or less.

  The equivalent ratio of the amine-based curing agent and the curing agent having an (active) ester group is preferably in the range of 1 or more and 9 or less. Within this range, flexibility, adhesion, and heat resistance can be obtained without lowering the glass transition temperature. A more preferable equivalent ratio is that the equivalent ratio of the polyamine compound and the curing agent having an (active) ester group is 1.5 or more and 4 or less.

The resin composition for printed circuit boards according to the present invention may further contain a phosphorus compound. Examples of phosphorus compounds include monomeric phosphate esters, condensed phosphate esters, polymerized phosphate esters, and phosphate ester amides. Of these, phosphoric ester amides are preferably used. Phosphoric ester amide is effective as a flame retardant containing no halogen. Since it is less hydrolysable than a general phosphoric acid ester, it is preferable because the heat resistance of the hygroscopic solder is improved and the migration resistance (insulation reliability) is not lowered.
The phosphorus content of the phosphoric ester amide is preferably 2% or more and 6% or less. The content of phosphoric ester amide is preferably 15% by weight or more and 33% by weight or less based on the entire resin composition. 18% by weight or more and 30% by weight or less is more preferable. Above the above lower limit, a flame retardant effect is obtained, and below the above upper limit, the compatibility with the epoxy resin is good, and when the varnish is formed, the varnish is uniformly dispersed.

The resin composition for printed circuit boards according to the present invention may further include a carboxyl group-containing rubber. The carboxyl group-containing rubber is preferably an acrylonitrile-butadiene rubber or an acrylonitrile-ethylene rubber. The content of the carboxyl group-containing rubber is preferably 6% by weight or more and 17% by weight or less. It is more preferably 8% by weight or more and 15% by weight or less. Above the lower limit, heat resistance is excellent, and below the upper limit, adhesion and flexibility are excellent.
The Mooney viscosity of the carboxyl group-containing rubber is preferably 20 or less, more preferably 10 or more and 20 or less. Above the lower limit, the compatibility with the epoxy resin is good, and below the upper limit, the resin does not leak out during press molding.

  The resin composition for printed circuit boards of the present invention may further contain an inorganic filler. Thereby, heat resistance improvement, an elastic modulus improvement, and a flame retardance can be improved. As the inorganic filler, aluminum hydroxide, fused silica, calcium carbonate, alumina, mica, talc, white carbon and the like are preferable. Among these, aluminum hydroxide is more preferable. The average particle diameter of the inorganic filler is not particularly limited, but is preferably 0.1 μm or more and 10 μm or less. When the average particle size is within this range, a good varnish viscosity can be obtained. Although content of the inorganic filler in a resin composition is not specifically limited, 10 weight% or more and 40 weight% or less are preferable with respect to the whole resin composition, and 20 weight% or more and 30 weight% or less are more preferable. If it is less than the said lower limit, hinge resistance and a flame retardance may fall. If the above upper limit is exceeded, adhesion and folding resistance may be reduced.

  The resin composition for printed circuit boards of the present invention may contain components other than those described above. For example, addition of silane coupling agents such as aminosilane or titanate coupling agents, epoxysilane coupling agents, defoaming agents, etc. to improve adhesion to copper foil and printed circuit boards and moisture resistance An agent may be included.

Hereinafter, the example of the preferable compounding quantity of this invention is shown.
Compounding amount (1)
(I) Flexible epoxy resin having a flexible structure 5 wt% to 40 wt%
(Ii) Bisphenol A type epoxy resin 10% by weight to 30% by weight
(Iii) Diaminodiphenylsulfone 5 wt% to 20 wt%
(Iv) Curing agent having an ester group 3% to 16% by weight

Compounding amount (2)
(I) Flexible epoxy resin having a flexible structure 5 wt% to 40 wt%
(Ii) Bisphenol A type epoxy resin 10% by weight to 30% by weight
(Iii) Diaminodiphenylsulfone 5 wt% to 20 wt%
(Iv) Curing agent having an ester group 3% to 16% by weight
Phosphoric ester amide 20 parts by weight to 70 parts by weight with respect to 100 parts by weight of the resins (i) to (iv) above

Compounding amount (3)
(I) Flexible epoxy resin having a flexible structure 5 wt% to 40 wt%
(Ii) Bisphenol A type epoxy resin 10% by weight to 30% by weight
(Iii) Diaminodiphenylsulfone 5 wt% to 20 wt%
(Iv) Curing agent having an ester group 3% to 16% by weight
Carboxyl group-containing rubber 10 parts by weight to 40 parts by weight with respect to 100 parts by weight of the resins (i) to (iv)

Blending amount (4)
(I) 5 to 40% by weight of a flexible epoxy resin having a flexible structure
(Ii) Bisphenol A type epoxy resin 10% by weight to 30% by weight
(Iii) Diaminodiphenylsulfone 5 wt% to 20 wt%
(Iv) Curing agent having an ester group 3% to 16% by weight
10 parts by weight to 40 parts by weight of an inorganic filler with respect to 100 parts by weight of the resins (i) to (iv) above

  Next, the insulating layer with a supporting substrate of the present invention will be described.

  The insulating layer with a supporting substrate is obtained by forming an insulating layer made of a resin composition for printed circuit boards on at least one surface side of a supporting substrate made of a metal foil or a resin film.

  An insulating layer with a supporting substrate using a resin film as a supporting substrate is used to cover and protect the surface of a conductor circuit provided on a printed circuit board, and particularly used as a coverlay film in a flexible printed circuit board. It has been. Moreover, the insulating layer with a supporting base material using the metal foil as the supporting base material may be used as RCF (Resin Coated Copper), which can also be used as a build-up material for a multilayer printed circuit board.

  A coverlay film provided with an insulating layer by applying it as a varnish on one side of the resin film is applied to the resin film with the above resin composition for printed circuit boards dissolved in a predetermined solvent at a predetermined concentration. After the process, it is produced by drying at 80 ° C. or more and 200 ° C. or less. About the thickness of the resin composition for printed circuit boards after drying, it coats so that it may become the range of 10 micrometers or more and 100 micrometers or less by a use. In the case of a coverlay film, a film such as polyethylene terephthalate, polyethylene, or polypropylene may be used as a release film on the surface of the resin composition after drying for the purpose of preventing foreign matter from entering.

  As the solvent used for the varnish, it is preferable to select a solvent having good solubility in the resin composition. For example, one or two of acetone, methyl ethyl ketone, toluene, xylene, n-hexane, methanol, ethanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methoxypropanol, cyclohexanone, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, etc. It is possible to use the above mixed system.

  Examples of the resin film include polyimide resin films such as polyimide resin films, polyetherimide resin films and polyamideimide resin films, polyamide resin films such as polyamide resin films, and polyester resin films such as polyester resin films. Among these, a polyimide resin film is particularly preferably used from the viewpoint of improving the elastic modulus and heat resistance.

  Although the thickness of a resin film is not specifically limited, 5 micrometers or more and 50 micrometers or less are preferable, More preferably, they are 5 micrometers or more and 25 micrometers or less. When the thickness is within this range, the flexibility is particularly excellent.

Insulating layer (RCF) with a supporting substrate using a metal foil is applied to the metal foil with a resin composition for a printed circuit board in a predetermined solvent and a varnish dissolved at a predetermined concentration in the same manner as the coverlay film described above. After the process, it is produced by drying at 80 ° C. or more and 200 ° C. or less. About the thickness of the resin composition for printed circuit boards after drying, it coats so that it may become the range of 8 micrometers or more and 50 micrometers or less by a use. Also in the case of RCF, after drying, a film such as polyethylene terephthalate, polyethylene, or polypropylene may be used as a release film on the surface of the resin composition for a printed circuit board for the purpose of preventing contamination.
Examples of the metal constituting the metal foil include copper and a copper-based alloy, aluminum and an aluminum-based alloy, iron and an iron-based alloy, and copper is more preferable.
Although the thickness of metal foil is not specifically limited, 6 micrometers or more and 70 micrometers or less are preferable, and 9 micrometers or more and 18 micrometers or less are especially preferable. When the thickness is within this range, the flexibility and folding resistance are particularly excellent. What is necessary is just to select suitably the solvent similar to the solvent used for the coverlay film mentioned above as a solvent used for a varnish.

  Next, the laminated board of this invention is demonstrated.

  In the laminated board, metal foil is laminated and formed on at least one surface side of the support base made of the resin film via an insulating layer made of a resin composition for printed circuit boards.

The laminate is prepared by applying a varnish on one or both sides of a base material and drying it, and then laminating a metal foil on the resin composition surface by a thermocompression roll or the like.
Examples of the metal constituting the metal foil include copper and a copper-based alloy, aluminum and an aluminum-based alloy, iron and an iron-based alloy, and copper is more preferable.
Examples of the base material include an insulating film. Examples of the resin film include a polyimide resin film such as a polyimide resin film, a polyetherimide resin film, and a polyamideimide resin film, and a polyamide resin such as a polyamide resin film. Examples thereof include polyester resin films such as films and polyester resin films. Among these, a polyimide resin film is particularly preferably used from the viewpoint of improving the elastic modulus and heat resistance. Further, as a base material, a metal foil may be laminated and bonded to a prepreg in which a base material such as a glass woven fabric, a glass nonwoven fabric, or a polyester nonwoven fabric is impregnated with a resin composition for a printed circuit board.

  What is necessary is just to select suitably the solvent similar to the solvent used for the coverlay film mentioned above as a solvent used for a varnish.

  Next, the printed circuit board of the present invention will be described.

  The printed circuit board of the present invention comprises a conductive circuit formed by etching a metal foil of a laminate, and an insulating layer (cover lay film) made of a resin composition for printed circuit boards on one surface side of a support base made of a resin film. ) To cover the conductor circuit. In the above coverlay film, unnecessary portions are removed in advance. As a removing method, for example, it may be punched out using a mold or the like, or drilled with an NC drill, NC router or the like. From the viewpoint of workability and productivity, it is preferable to punch using a mold. And a method of laminating a coverlay film on a necessary part of a conductor circuit, and carrying out pressure bonding with a hot-pressure forming device can be used. In this case, the pressure bonding conditions can be, for example, a pressure bonding temperature of 80 ° C. or higher and 220 ° C. or lower and a pressure bonding pressure of 0.2 MPa or higher and 10 MPa or lower.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.

(Example 1)
As resin composition, 29 parts by weight of bisphenol A type epoxy resin (epoxy equivalent 185, manufactured by Dainippon Ink and Industries) and 8 parts by weight of flexible epoxy resin having flexible structure (YL-7175-500, manufactured by Japan Epoxy Resin), 9 parts by weight of diaminodiphenyl sulfone (3, 3-DAS manufactured by Mitsui Chemicals) as a curing agent, and 16 parts by weight of a resin having a reactive ester group with an ester equivalent of 223 (Epicron EXB-9451, manufactured by Dainippon Ink Industries, Ltd.) 24 parts by weight of phosphoric ester amide containing 10% phosphorus in one molecule, 12 parts by weight of acrylonitrile butadiene rubber (Nippon Zeon, Nipol 1072J) as carboxyl group-containing rubber, and 2 parts by weight of silane coupling agent The resin solid content is 50% in the mixed solvent of MEK and butyl cellosolve. It was dissolved.
This compound varnish is coated on one side of a 25 μm thick polyimide film with a comma roll coater so that the thickness of the resin composition is 10 μm, dried at 120 ° C. for 5 minutes + 150 ° C. for 5 minutes, and then rolled copper foil (Fukuda Metal Foil Industry Co., Ltd., 18 μm thick) is laminated at 150 ° C. with a heat roll, coated with varnish, dried, rolled copper foil is laminated, this is cured at 180 ° C. for 1 hour, and one side for a flexible printed circuit board A copper clad laminate was obtained. Similarly, varnish was coated on the opposite side, dried, and rolled copper foil was laminated, and this was cured at 180 ° C. for 1 hour to obtain a double-sided copper-clad laminate for flexible printed circuit boards.
Predetermined circuit creation was performed on this in a normal circuit creation process (drilling, plating, DFR lamination, exposure / development, etching, DFR peeling).
Furthermore, the same composition varnish is coated on a single side of a polyimide film having a thickness of 12.5 μm with a comma roll coater so that the thickness of the resin composition is 25 μm, and dried at 120 ° C. for 5 minutes + 150 ° C. for 5 minutes to cover A lay film was obtained. An opening was provided at a predetermined position of the cover lay film, and a flexible printed circuit board for evaluation was prepared by attaching the hole to a predetermined position on both surfaces of the previously prepared evaluation substrate with a vacuum press at 160 ° C. for 1 hour.

(Example 2)
The copper-clad laminate and coverlay film for flexible printed circuit boards were the same as in Example 1 except that the amount of bisphenol A type epoxy resin in Example 1 was 12 parts by weight. The flexible printed circuit board for evaluation was produced.

(Example 3)
Except for blending 27 parts by weight of the bisphenol A type epoxy resin of Example 1, the amounts shown in Table 1 were used, and in the same manner as in Example 1, a copper-clad laminate for a flexible printed circuit board and A cover lay film was obtained to produce a flexible printed circuit board for evaluation.

Example 4
Except for blending the bisphenol A type epoxy resin of Example 1 so as to be 15 parts by weight, the blending amounts shown in Table 1 were used, and in the same manner as in Example 1, a copper-clad laminate for a flexible printed circuit board and A cover lay film was obtained to produce a flexible printed circuit board for evaluation.

(Example 5)
Except for blending the bisphenol A type epoxy resin of Example 1 so as to be 18 parts by weight, the blending amounts shown in Table 1 were used, and in the same manner as in Example 1, a copper-clad laminate for a flexible printed circuit board and A cover lay film was obtained to produce a flexible printed circuit board for evaluation.

(Example 6)
Except for blending the bisphenol A type epoxy resin of Example 1 so as to be 11 parts by weight, the blending amounts shown in Table 1 were used, and in the same manner as in Example 1, a copper-clad laminate for a flexible printed circuit board and A cover lay film was obtained to produce a flexible printed circuit board for evaluation.

(Example 7)
Except for blending the bisphenol A type epoxy resin of Example 1 so as to be 25 parts by weight, the blending amounts shown in Table 1 were used, and in the same manner as in Example 1, a copper-clad laminate for a flexible printed circuit board and A cover lay film was obtained to produce a flexible printed circuit board for evaluation.

(Example 8)
Except for blending the bisphenol A type epoxy resin of Example 1 so as to be 14 parts by weight, the blending amounts shown in Table 1 were used, and in the same manner as in Example 1, a copper-clad laminate for flexible printed circuit boards and A cover lay film was obtained to produce a flexible printed circuit board for evaluation.

Example 9
18 parts by weight of a bisphenol A type epoxy resin as a resin component, 21 parts by weight of a flexible epoxy resin having a flexible structure, 9 parts by weight of diaminodiphenylsulfone as a curing agent, and 16 parts by weight of a resin having a reactive ester group, Add 15 parts by weight of aluminum hydroxide (average particle size: 1 μm, Nippon Light Metal Co., Ltd. B1403) as an inorganic filler and disperse with a kneading machine, 23 parts by weight of phosphoric ester amide, 12 parts by weight of carboxyl group-containing rubber And 2 parts by weight of a silane coupling agent were dissolved in a mixed solvent of MEK and butyl cellosolve so that the resin solid content was 50%.
Hereinafter, this compound varnish was obtained in the same manner as in Example 1 to obtain a copper-clad laminate and a coverlay film for a flexible printed circuit board, and a flexible printed circuit board for evaluation was prepared.

(Example 10)
As resin composition, 14 parts by weight of bisphenol A type epoxy resin, 29 parts by weight of flexible epoxy resin having flexible structure, 4 parts by weight of biphenyl aralkyl epoxy resin (epoxy equivalent 291; NC-3000 manufactured by Nippon Kayaku), cured 7 parts by weight of diaminodiphenylsulfone as the agent, 13 parts by weight of a resin having a reactive ester group, 20 parts by weight of phosphoric ester amide, 10 parts by weight of carboxyl group-containing rubber (Nippon Zeon, Nipol 1072J), and silane 2 parts by weight of the coupling agent was dissolved in a mixed solvent of MEK and butyl cellosolve so that the resin solid content was 50%.
Hereinafter, this compound varnish was obtained in the same manner as in Example 1 to obtain a copper-clad laminate and a coverlay film for a flexible printed circuit board, and a flexible printed circuit board for evaluation was prepared.

(Example 11)
Except for blending the bisphenol A type epoxy resin of Example 10 so as to be 11 parts by weight, the blending amounts shown in Table 1 were used, and in the same manner as in Example 1, a copper-clad laminate for flexible printed circuit boards and A cover lay film was obtained to produce a flexible printed circuit board for evaluation.

(Comparative Example 1)
Examples of the resin composition are as shown in Table 1, except that two types of epoxy resins are compounded by 39 parts by weight of bisphenol A type epoxy resin alone and two parts of curing agent by 24 parts by weight of diaminodiphenylsulfone alone. In the same manner as in Example 1, a copper-clad laminate and a coverlay film for a flexible printed circuit board were obtained, and a flexible printed circuit board for evaluation was produced.

(Comparative Example 2)
The compounding amount shown in Table 1 except that 50 parts by weight of the flexible epoxy resin containing two types of epoxy resins as the resin composition and 12 parts by weight of diaminodiphenylsulfone alone are blended with the two types of curing agents. As in Example 1, a copper-clad laminate for a flexible printed circuit board and a coverlay film were obtained, and a flexible printed circuit board for evaluation was produced.

(Comparative Example 3)
The compounding amounts shown in Table 1 are as follows, except that two types of epoxy resins are blended in 33 parts by weight of the bisphenol A type epoxy resin alone and two types of curing agents are blended in 36 parts by weight of the reactive ester group-containing resin alone. In the same manner as in Example 1, a copper-clad laminate and a coverlay film for a flexible printed circuit board were obtained, and a flexible printed circuit board for evaluation was produced.

(Comparative Example 4)
Example 1 with the exception that 44 parts by weight of a flexible epoxy resin alone containing 2 types of epoxy resins as resin components and 18 parts by weight of a resin containing a reactive ester group alone were combined with 2 types of curing agents Similarly, a copper-clad laminate and a coverlay film for a flexible printed circuit board were obtained, and a flexible printed circuit board for evaluation was produced.

(Comparative Example 5)
In Comparative Example 1, 25 parts by weight of bisphenol A type epoxy resin, 7 parts by weight of flexible structure-containing flexible epoxy resin, and 25 parts by weight of a novolak phenol resin (PR-53647 made by Sumitomo Bakelite) alone were added. In the same manner as in Example 1, a copper-clad laminate and a coverlay film for a flexible printed circuit board were obtained, and a flexible printed circuit board for evaluation was produced.

  Table 1 shows the composition of each example and comparative example.

  The flexible circuit board thus obtained was evaluated for punchability, moldability, moisture-absorbing solder heat resistance, adhesion, electrical insulation, bendability, folding resistance, flexibility, flame resistance, and warpage. It shows in Table 2.

  From the above results, the resin compositions for printed circuit boards of Examples 1 to 11 all had good results in both high flexibility and folding resistance (flexibility).

-Punching property The cover lay film was punched out of the film before lamination, and the end face was observed.
・ Moldability The maximum amount of protrusion from the edge of the coverlay film punched out to expose the measurement terminals was 0.1 mm or less, and the presence or absence of voids due to imbedding defects such as between circuits was not confirmed. ○.
・ Hygroscopic solder heat resistance Conforms to JIS standard C5016-10.3. The ones that did not come off or peeled off were marked with ◯.
-Adhesion strength Conforms to JIS standard C5016-8.1. Adhesive strength is 1.0 N / mm or more ◎, 0.6 N / mm or more and less than 1.0 N / mm ○, 0.4 N / mm or more and less than 0.6 N / mm △, less than 0.4 N / mm × It was.
-Electrical insulation L / S = 40 μm / 40 μm Using five comb patterns, the initial state and the insulation resistance value after treatment at 65 ° C. 90% 50 V 1000 hours were measured. A sample having an insulation resistance value of 10 ¹⁰ or more both after the initial value and after the treatment was evaluated as ◯.
-Flexibility Conforms to the IPC method. R = 2 mm, 1000 rpm, stroke 15 mm, the number of flexing times is 10 million times or more, ◎, 5 million times to less than 10 million times ○, 100,000 times to less than 5 million times △, 10 What was less than 10,000 times was set as x.
-Folding resistance A double-sided plate with a circuit width of 1 cm and a circuit width of 100 μm is folded by 180 ° in the direction orthogonal to the circuit and opened, and the same part is folded and opened again. By repeating this, the change rate of the conduction resistance value was less than 1% compared to the initial value, ◎, 1% to less than 5%, ％, 5% to less than 10%, ％, and 10% or more to ×.
・ Flexibility
A loop having a diameter of 20 mm is made from a sample obtained by punching a single-sided copper-clad laminate that has been etched on the entire surface into 10 mm × 100 mm so that the adhesive layer is on the outside. The repulsive force when the loop was crushed by 15 mm was measured.
A repulsive force of less than 0.5 g was evaluated as ◎, 0.5 g or more and less than 1.0 g as ◯, 1.0 g or more and less than 2.0 g as Δ, and 2.0 g or more as x.
・ Flame retardance An evaluation was performed in accordance with the UL law. V-0 or VTM-0 was marked with ◎, V-1 or VTM-1 was marked with ◯, and the others were marked with x.
-Warpage amount For single-sided copper-clad laminates in which component mounting parts (2 cm in length and 2 cm in width) are connected by a circuit width and an inter-circuit width of 75 μm, this single-sided board is placed on a surface plate, from the surface plate to the component mounting portion. The height of the warp was measured. The height of the warp was 0 mm, 未 満 if less than 1.0 mm, Δ if 1.0 mm or more and less than 2.0 mm, and x if 2.0 mm or more.

Claims (12)

  A flexible epoxy resin (a) having a flexible structure, an epoxy resin (b) having two or more epoxy groups in one molecule, an amine-based curing agent (c), and a curing agent having an ester group ( d), and a resin composition for printed circuit boards. The flexible epoxy resin (a) which has the said flexible structure is a resin composition for printed circuit boards of Claim 1 represented by following General formula (1).

  The resin composition for a printed circuit board according to claim 1, wherein the curing agent having an ester group is an aromatic ester compound obtained by a condensation reaction of a polyvalent aromatic carboxylic acid and a polyhydric phenol. object. The resin composition for a printed circuit board according to claim 3, wherein the curing agent having an ester group is an aromatic ester compound having a structural unit represented by the following chemical formula (1) in the main chain skeleton.

  The equivalent ratio ((a) / (b)) of the flexible epoxy resin (a) having a flexible structure to the epoxy resin (b) having two or more epoxy groups in one molecule is 0.1. The resin composition for a printed circuit board according to any one of claims 1 to 4, wherein the resin composition is 1.0 or less.   The print according to any one of claims 1 to 5, wherein an equivalent ratio ((c) / (d)) of the amine-based curing agent (c) and the curing agent (d) having an ester group is 1 or more and 9 or less. A resin composition for circuit boards.   The resin composition for printed circuit boards according to any one of claims 1 to 6, further comprising a phosphorus compound.   The resin composition for printed circuit boards according to any one of claims 1 to 7, further comprising a carboxyl group-containing rubber.   The resin composition for a printed circuit board according to any one of claims 1 to 8, further comprising an inorganic filler having an average particle size of 0.1 µm or more and 10 µm or less.   An insulating layer with a supporting substrate, wherein an insulating layer made of the resin composition for printed circuit boards according to any one of claims 1 to 9 is formed on at least one surface side of a supporting substrate made of a metal foil or a resin film. .   The laminated board by which metal foil was laminated | stacked and formed on the at least one surface side of the support base material consisting of the said resin film of Claim 10 via the insulating layer which consists of a resin composition for printed circuit boards.   The insulating layer which consists of a resin composition for printed circuit boards formed in the one surface side of the support base material which consists of the said resin film while forming a conductor circuit by etching the metal foil of the said laminated board of Claim 11 A printed circuit board laminated so as to cover the conductor circuit via a wire.