JP2005105182A - Resin composition, prepreg and laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition that is halogen-free and excellent in adhesion and that has reduced resin flow, and to provide a prepreg and a laminate. <P>SOLUTION: The resin composition is used for manufacturing a sheet-like prepreg by impregnating a substrate with the resin composition and comprises 20-60 pts. wt. bisphenol-type epoxy resin having an epoxy equivalent of 150-250, 20-120 pts. wt. bisphenol-type epoxy resin having an epoxy equivalent of 1,000-2,000, 15-60 pts. wt. curing agent comprising a novolac-type phenol resin represented by formula (1), 20-100 pts. wt. synthetic rubber and 30-100 pts. wt. phosphorus compound. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resin composition, a prepreg, and a laminate.

  The multilayer flexible circuit board has a multilayer part and a flexible part, and a prepreg is used for stacking the printed circuit boards in the multilayer part. The flexible part has one or two conductor layers, and a single-sided or double-sided flexible printed circuit board is used.

  Conventionally, prepregs that have been used as insulating base materials for rigid circuit boards require superiority in sheet thickness accuracy and voidlessness, and therefore the resin flow during molding is relatively large. When this is applied as it is to a multilayer flexible printed circuit board, a resin flow of prepreg occurs from the multilayer portion to the flexible portion, and there are disadvantages such as loss of the flexible properties after molding. Therefore, a non-flow prepreg with less resin flow is required for the multilayer flexible circuit board.

  Moreover, it is requested | required not to contain a halogen as a flame retardant from the environmental response problem. As a conventional flame retardant adhesive, it is common to use a brominated epoxy resin (for example, Patent Documents 1 and 2). However, there is a concern about generation of dioxin during combustion, and a halogen-free material is required. .

In the case of a non-flow prepreg, an epoxy resin is often used. In order to adjust the resin flow degree, the reaction of the epoxy resin is advanced to adjust the degree of cure of the prepreg, thereby increasing the melt viscosity of the resin. With a resin system having a fast curing reaction, it is difficult to control the degree of curing, and there is a possibility that the adhesion to a substrate such as a polyimide film or metal foil which is a counterpart during adhesive molding may be reduced.
JP 7-162113 A JP-A-10-212737

  An object of the present invention is to provide a resin composition, a prepreg, and a laminate that are halogen-free and excellent in adhesion and have a small resin flow.

（２）前記硬化剤のうち化（１）で表されるノボラック型フェノール樹脂が３０〜６０重量％である上記（１）に記載の樹脂組成物。
（３）前記リン化合物が化（２）または化（３）である上記（１）または（２）に記載の樹脂組成物。

（４）上記（１）ないし（３）のいずれかに記載の樹脂組成物を基材に含浸させてなることを特徴とするプリプレグ。
（５）上記（４）に記載のプリプレグを一枚以上積層してなることを特徴とする積層板。 Such an object is achieved by the present invention described in the following (1) to (5).
(1) A resin composition used for impregnating a base material to form a sheet-like prepreg, wherein an epoxy equivalent is 20 to 60 parts by weight of a bisphenol type epoxy resin having an epoxy equivalent of 150 to 250, and an epoxy equivalent is 1000 to 2000. 20 to 120 parts by weight of a bisphenol type epoxy resin, 15 to 60 parts by weight of a curing agent containing a novolac type phenol resin represented by the following chemical formula (1), 20 to 100 parts by weight of a synthetic rubber, and 30 to 100 parts by weight of a phosphorus compound The resin composition characterized by the above-mentioned.

(2) The resin composition as described in said (1) whose novolak-type phenol resin represented by Chemical formula (1) is 30-60 weight% among the said hardening | curing agents.
(3) The resin composition according to the above (1) or (2), wherein the phosphorus compound is Chemical Formula (2) or Chemical Formula (3).

(4) A prepreg obtained by impregnating a base material with the resin composition according to any one of (1) to (3).
(5) A laminate comprising one or more of the prepregs described in (4) above.

  According to the present invention, it is possible to provide a resin composition, a prepreg, and a laminate that are halogen-free, have excellent adhesion, and have a small resin flow.

Hereinafter, the resin composition, prepreg, and laminate of the present invention will be described in detail.
The resin composition of the present invention is a resin composition used for impregnating a base material to form a sheet-like prepreg, and includes a bisphenol-type epoxy resin, a novolac-type phenol resin, a synthetic rubber, and a phosphorus compound. It is a feature.
Moreover, the prepreg of the present invention is characterized in that a base material is impregnated with the above-mentioned resin composition.
The laminate of the present invention is characterized in that one or more of the prepregs described above are laminated.

Hereinafter, the resin composition of the present invention will be described in detail.
In the resin composition of the present invention, a linear bisphenol type epoxy resin having two different epoxy equivalents is used. Thereby, the resin flow at the time of press molding can be reduced. As the epoxy resin, two kinds of linear bisphenol type epoxy resins having an epoxy equivalent of 150 to 250 and 1000 to 2000 are used. The first epoxy resin uses an epoxy equivalent of 150 to 250. The first resin is a liquid having a viscosity at 25 ° C., and has a viscosity as low as 3000 to 4500 mPa · s, but can provide an effect of high adhesion. When the epoxy equivalent is less than 150, the compatibility is lowered, and when the epoxy equivalent exceeds 250, the adhesiveness is lowered.
The content of the first resin is preferably 20 to 60 parts by weight. If it is less than 20 parts by weight, the wettability with the adhesion target is poor, and if it exceeds 60 parts by weight, it becomes difficult to control the resin flow.

As the second epoxy resin, an epoxy equivalent of 1000 to 2000 is used. The second resin is solid at room temperature (around 25 ° C.) and is effective for resin flow control. If the epoxy equivalent is less than 1000, powder falling occurs and the resin flow increases. If the epoxy equivalent exceeds 2000, the compatibility and the impregnation property to the substrate are lowered.
The content of the second resin is preferably 20 to 120 parts by weight. If it is less than 20 parts by weight, it is difficult to control the resin flow, and if it exceeds 120 parts by weight, there is an influence such as a decrease in adhesion. Due to the balance between the equivalent amount and the blending amount of these two kinds of bisphenol type epoxy resins, it is possible to achieve good adhesion performance and compatibility, impregnation into glass cloth, resin flow and powder fall.

前記ノボラック型フェノール樹脂は、トリアジン環を有するノボラックフェノール型樹脂を用いる。トリアジン環は窒素を含んでおり難燃効果に寄与する。また第一級アミンを有しており、これがエポキシ樹脂の硬化反応に寄与する。
これにより多段的な硬化反応が期待され、硬化度合いのコントロールを容易にし、密着性を損なうことなく樹脂フローを抑制することを可能とした。
前記ノボラック型フェノール樹脂の含有量は、前記硬化剤全体量の３０〜６０重量％含む事が好ましい。配合量が３０重量％未満では、トリアジン環の難燃効果が得られ難く、６０重量％を超えると反応に寄与していない硬化剤が残るため、樹脂フローが多くなる原因となる。
他の硬化剤としては、特に限定はされないが、ノボラック型フェノール樹脂、ノボラック型クレゾール樹脂、等が挙げられる。これらの中でもノボラック型フェノール樹脂が好ましい。 In the resin composition of the present invention, a curing agent is used.
The content of the curing agent is preferably 15 to 60 parts by weight. If the amount is less than 15 parts by weight, the obtained cured product does not have chemical resistance or solvent resistance. When it exceeds 60 parts by weight, the resin flow increases because a curing agent that does not contribute to the reaction remains.
A part of the curing agent uses a novolac type phenol resin represented by the following chemical formula (1).

As the novolac type phenol resin, a novolac phenol type resin having a triazine ring is used. The triazine ring contains nitrogen and contributes to the flame retardant effect. It also has a primary amine, which contributes to the curing reaction of the epoxy resin.
As a result, a multistage curing reaction is expected, the degree of curing can be easily controlled, and the resin flow can be suppressed without impairing the adhesion.
The content of the novolac type phenol resin is preferably 30 to 60% by weight of the total amount of the curing agent. If the blending amount is less than 30% by weight, the flame retardant effect of the triazine ring is difficult to obtain, and if it exceeds 60% by weight, a curing agent that does not contribute to the reaction remains, which causes an increase in the resin flow.
Although it does not specifically limit as another hardening | curing agent, A novolak-type phenol resin, a novolak-type cresol resin, etc. are mentioned. Among these, novolac type phenol resins are preferable.

In the resin composition of the present invention, synthetic rubber is used. Thereby, resin flow control, adhesion improvement, and powder falling off during prepreg cutting can be prevented.
The synthetic rubber is not particularly limited, and examples thereof include NBR, acrylic rubber, polybutadiene, isoprene, carboxylic acid-modified NBR, hydrogen conversion polybutadiene, and epoxy-modified polybutadiene. Among these, the solid type is more preferable than the liquid type because the workability during temporary bonding is improved.
Further, it is preferable to use a carboxylic acid-modified, hydroxyl-modified or epoxy-modified product in order to improve compatibility with an epoxy resin or polyamideimide, or a hydrogen conversion type synthetic rubber to prevent thermal degradation.
The content of the synthetic rubber is preferably 20 to 100 parts by weight. If the amount is less than 20 parts by weight, it becomes difficult to control powder flow and resin flow control. If the amount exceeds 100 parts by weight, the heat resistance decreases, the linear expansion coefficient increases, and the interlayer connection through-hole used in the multilayer flexible circuit board. Cause disconnection.

化（２）のリン化合物はメチルエチルケトンやアセトンに比較的易溶であり、相溶性、作業性が良く高い難燃効果が得られる。また、化（３）のリン化合物は一般的な有機溶剤に難溶であり、無機フィラーのように固体として添加することが出来るので、樹脂フローの抑制、密着性の向上に効果がある。
前記リン化合物物の含有量は、３０〜１００重量部が望ましい。３０重量部未満だと難燃効果が得られず、１００重量部を超えると相溶性が悪くなり、樹脂フロ−や密着性低下の原因となる。 In the resin composition of the present invention, a phosphorus compound is used. Thereby, a flame retardance can be improved.
As the phosphorus compound, a phosphorus compound represented by the following chemical formula (2) or (3) is used.

The phosphorus compound of Chemical formula (2) is relatively readily soluble in methyl ethyl ketone and acetone, and has a good compatibility and workability and a high flame retardant effect. Moreover, since the phosphorus compound of Chemical formula (3) is hardly soluble in a general organic solvent and can be added as a solid like an inorganic filler, it is effective in suppressing resin flow and improving adhesion.
The phosphorus compound content is preferably 30 to 100 parts by weight. If the amount is less than 30 parts by weight, the flame retardant effect cannot be obtained.

Next, the prepreg will be described.
The prepreg of the present invention is obtained by impregnating a base material with the above resin composition. Thereby, it is possible to obtain a prepreg which is halogen-free and excellent in adhesion and has a small resin flow.
Examples of the base material used in the present invention include glass fiber base materials such as glass fiber cloth and glass non-woven cloth, or inorganic fiber base materials such as fiber cloth and non-fiber cloth containing inorganic compounds other than glass, aromatic polyamide resins, polyamides. Examples thereof include organic fiber base materials composed of organic fibers such as resins, aromatic polyester resins, polyester resins, polyimide resins, and fluororesins. Among these base materials, glass fiber base materials represented by glass woven fabric are preferable in terms of strength and water absorption.

  Examples of the method of impregnating the substrate with the resin composition obtained in the present invention include a method of immersing the substrate in a resin varnish, a method of applying with various coaters, and a method of spraying with a spray. Among these, the method of immersing the base material in the resin varnish is preferable. Thereby, the impregnation property of the resin composition with respect to a base material can be improved. In addition, when a base material is immersed in a resin varnish, a normal impregnation coating equipment can be used.

The solvent used for the resin varnish must be selected so that it does not remain in the adhesive when the substrate is impregnated with the resin composition and then dried. Examples include acetone, methyl ethyl ketone, toluene, xylene, n-hexane, methanol, ethanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methoxypropanol, and cyclohexanone.
The solid content of the resin varnish is not particularly limited, but the solid content of the resin composition is preferably 40 to 80% by weight, and particularly preferably 50 to 65% by weight. Thereby, the impregnation property to the base material of a resin varnish can further be improved. A prepreg can be obtained by impregnating the base material with the resin composition and drying at a predetermined temperature, for example, 80 to 200 ° C.

Next, a laminated board is demonstrated.
The laminate of the present invention is formed by molding at least one prepreg described above. In the case of a single prepreg, a metal foil or film is stacked on both upper and lower surfaces or one surface. Two or more prepregs can be laminated. When two or more prepregs are laminated, a metal foil or film is laminated on the outermost upper and lower surfaces or one surface of the laminated prepreg. Next, a laminate can be obtained by heating and pressurizing a laminate of a prepreg and a metal foil. Although the temperature to heat is not specifically limited, 120-220 degreeC is preferable and especially 150-200 degreeC is preferable. Moreover, the pressure to pressurize is not particularly limited, but is preferably 0.5 to 4 MPa, and particularly preferably 1.0 to 3.5 MPa. Thereby, the laminated board with high thickness accuracy and excellent moldability can be obtained. The resin composition in the present invention uses a higher polymer resin and has a high melt viscosity. Therefore, it is possible to reduce the resin flow-out due to the press or roll, and to increase the thickness accuracy.

Examples of the metal constituting the metal foil include copper and a copper alloy, aluminum and an aluminum alloy, iron and an iron alloy, and the like.
Examples of the film include polyethylene and polypropylene.

A multilayer flexible circuit board can be obtained by using the prepreg obtained as described above as an interlayer adhesive of the flexible circuit board.
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, 25 parts by weight of bisphenol A type epoxy resin (epoxy equivalent 185, EPICLON 840S manufactured by Dainippon Ink & Chemicals), 100 parts by weight of bisphenol A type epoxy resin (epoxy equivalent 1400, Epicoat E1016B50 manufactured by Japan Epoxy Resin Co., Ltd.), novolak type 11 parts by weight of phenolic resin (in-house developed product, PR-NMD-103), 9 parts by weight of novolac-type triazine phenolic resin (OH equivalent 125, Phenolite LA-7054 manufactured by Dainippon Ink Chemical Co., Ltd.), carboxyl group-containing acrylonitrile butadiene rubber ( Nippon Zeon (Nippol1072J) 50 parts by weight, phosphoric ester amide (phosphorus content 10%, Shikoku Kasei SP-703) as a flame retardant compounded so that the phosphorus content is 3% of the total resin solids And M The mixture was stirred in a mixed solvent of EK and butyl cellosolve so that the nonvolatile content was 20 to 25%. The resin varnish was impregnated into a 88 μm thick glass cloth and dried at 190 ° C. for 5 minutes to obtain a prepreg.
The obtained printed circuit board prepreg was thermocompression-molded at 190 ° C. for 2 hours on a polyimide surface of a single-sided copper-clad laminate by a vacuum press to obtain a substrate for evaluation.

(Example 2)
An evaluation board was obtained and evaluated in the same manner as in Example 1 except that the blending amount of the bisphenol A type epoxy resin having an epoxy equivalent of 185 was 20 parts by weight.

(Example 3)
An evaluation board was obtained and evaluated in the same manner as in Example 1 except that the amount of the bisphenol A type epoxy resin having an epoxy equivalent of 185 was changed to 60 parts by weight.

Example 4
An evaluation board was obtained and evaluated in the same manner as in Example 1 except that the blending amount of the bisphenol A type epoxy resin having an epoxy equivalent of 1400 was 20 parts by weight.

(Example 5)
An evaluation substrate was obtained and evaluated in the same manner as in Example 1 except that the blending amount of the bisphenol A type epoxy resin having an epoxy equivalent of 1400 was 120 parts by weight.

(Example 6)
An evaluation substrate was obtained and evaluated in the same manner as in Example 1 except that the amount of the carboxyl group-containing acrylonitrile butadiene rubber was 20 parts by weight.

(Example 7)
An evaluation substrate was obtained and evaluated in the same manner as in Example 1 except that the amount of the carboxyl group-containing acrylonitrile butadiene rubber was 100 parts by weight.

(Comparative Example 1)
Except for using a bisphenol A type epoxy resin having an epoxy equivalent of 185 and using a cresol novolac type epoxy resin (epoxy equivalent of 200, N-655-EXP-S manufactured by Dainippon Ink Co., Ltd.), the same as in Example 1. An evaluation board was obtained and evaluated in the same manner.

(Comparative Example 2)
An evaluation board was obtained in the same manner as in Example 1 except that a phenoxy resin (epoxy equivalent 7800, JER-1256B40 manufactured by Japan Epoxy Resin Co., Ltd.) was used without using a bisphenol A type epoxy resin having an epoxy equivalent of 1400. did.

(Comparative Example 3)
An evaluation substrate was obtained and evaluated in the same manner as in Example 1 except that dicyandiamide was used as a curing agent.

(Comparative Example 4)
An evaluation substrate was obtained and evaluated in the same manner as in Example 1 except that the carboxyl group-containing acrylonitrile butadiene rubber was not used.

(Comparative Example 5)
An evaluation substrate was obtained and evaluated in the same manner as in Example 1 except that the blending amount of the carboxyl group-containing acrylonitrile butadiene rubber was 150 parts by weight.

(Comparative Example 6)
An evaluation substrate was obtained and evaluated in the same manner as in Example 1 except that triphenylphosphine was used as the flame retardant.

The evaluation substrate thus obtained was measured and evaluated for the resin flow amount, powder falling at the time of cutting, moisture-absorbing solder heat resistance, adhesion, electrical insulation and flame retardancy, and the results are shown in Tables 1 and 2.

＊樹脂フロー
熱圧着成形後、ガラスクロス端部より染み出ている樹脂部位を金属顕微鏡にて測長した。（n=20）
＊ガラスクロスへの含浸性
樹脂組成物の相溶性、樹脂組成物のガラスクロスへの含浸性、及び乾燥後の発泡等の異常が無いか、外観にて確認した。
＊切断時の粉落ち
プリプレグ成形前及び成形後のリングカッターまたはビク抜きによる切断時に粉落ちが発生するか否かを目視にて判断した。
＊吸湿はんだ耐熱性
ＪＩＳ規格Ｃ５０１６−１０．３に順ずる。フクレ、剥がれが無いか確認した。
＊密着力
ＪＩＳ規格Ｃ５０１６−８．１に順ずる。
＊電気絶縁性
ＪＩＳ規格Ｋ６９１１に順ずる。硬化品を測定。
＊難燃性
ＵＬ規格ＵＬ９４Ｖに順ずる。

* Resin Flow After thermocompression molding, the resin part that exudes from the edge of the glass cloth was measured with a metal microscope. (N = 20)
* Impregnation into glass cloth The compatibility of the resin composition, the impregnation property of the resin composition into the glass cloth, and whether there were any abnormalities such as foaming after drying were confirmed by appearance.
* Powder fall at the time of cutting It was visually judged whether or not powder fall occurred at the time of cutting by the ring cutter or the big punch before and after the prepreg molding.
* Hygroscopic solder heat resistance Conforms to JIS standard C5016-10.3. It was confirmed that there was no swelling or peeling.
* Adhesive strength Conforms to JIS standard C5016-8.1.
* Electrical insulation Conforms to JIS standard K6911. Measure the cured product.
* Incombustibility Complies with UL standard UL94V.

  In recent years, as electronic devices have become smaller, lighter, and higher in density, printed circuit boards having higher density and higher fine circuit patterns have been required. In order to solve this problem, multilayer flexible printed circuit boards in which flexible printed circuit boards are laminated have been manufactured. The multilayer flexible printed circuit board is a printed circuit board having a conductor pattern in three or more layers including the surface conductor layer. The surface conductor circuit is referred to as an outer layer circuit, and the conductor layer in the insulating layer is referred to as an inner layer circuit. The multilayer flexible printed circuit board is made from an inner layer circuit board obtained by processing a printed circuit board and a base material such as glass cloth or non-woven fabric, impregnated with a resin and made into a semi-cured state, from a metal foil or a printed circuit board used as an outer layer circuit It can be obtained by sandwiching this between metal plates and applying heat and pressure to cure and mold the prepreg. Through the prepreg, electrical connection between conductors of different layers is performed by through-hole plating. INDUSTRIAL APPLICABILITY The present invention is used for a prepreg for a multilayer flexible printed circuit board having a small resin flow and excellent moldability and heat resistance when laminated by heating and pressing.

Claims (5)

A resin composition used for impregnating a base material to form a sheet-like prepreg, comprising 20 to 60 parts by weight of an epoxy equivalent of 150 to 250 bisphenol type epoxy resin and an epoxy equivalent of 1000 to 2000 bisphenol type epoxy 20 to 120 parts by weight of a resin, 15 to 60 parts by weight of a curing agent containing a novolac type phenol resin represented by the following chemical formula (1), 20 to 100 parts by weight of a synthetic rubber, and 30 to 100 parts by weight of a phosphorus compound A resin composition.

2. The resin composition according to claim 1, wherein the novolak type phenol resin represented by chemical formula (1) is 30 to 60 wt% of the curing agent. The resin composition according to claim 1 or 2, wherein the phosphorus compound is Chemical Formula (2) or Chemical Formula (3).

A prepreg obtained by impregnating a base material with the resin composition according to any one of claims 1 to 3. A laminate obtained by laminating one or more prepregs according to claim 4.