JP2007184558A - Curing resin composition, and prepreg and multilayer printed wiring board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curing resin composition that exhibits excellent flame resistance, heat resistance and moldability without including a halogen group flame retardant, has a longer pot life than conventional one, and is applicable to a relatively wide range of uses; and to provide a prepreg and a multilayer printed wiring board using the same. <P>SOLUTION: The curing resin composition comprises 35 to 75 pts.mass of (a) a compound having a dihydrobenzoxazine ring in a molecule, 10 to 25 pts.mass of (b) condensation polymer of a compound having phenol and triazine ring and aldehyde, 10 to 45 part mass of (c) an epoxy resin, and 5 to 35 pts.mass of (d) condensed phosphate per a total of 100 pts.mass of the above components (a), (b) and (c). Furthermore, it comprises 30 to 100 pts.mass of (e) inorganic filler per a total of 100 pts.mass of above (a), (b), (c) and (d), and the epoxy resin comprises 20 to 40 mass percent of bisphenol A type epoxy resin having an epoxy equivalent of 600 to 1500. The prepreg and multilayer printed wiring board using the same are also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a curable resin composition, and a prepreg and a multilayer printed wiring board using the same.

  Rigid flex printed wiring boards used for wiring of electrical and electronic equipment are generally molded and outer layer processed integrally with a flexible part of a flexible printed wiring board covered with a protective layer and a rigid part made of a rigid printed wiring board. A no-flow prepreg in which no resin oozes into the flexible part is used when the flexible part and the rigid part are integrally formed. This no-flow prepreg usually uses a flame retardant containing a halogen element such as brominated epoxy resin from the viewpoint of preventing fire and ignition and maintaining safety.

  However, in recent years, from the viewpoint of protecting and deteriorating the global environment and safety for the human body, technology to make prepreg flame retardant without using halogen-containing flame retardants that can generate highly toxic dioxins, benzofuran, etc. Is required. That is, electrical / electronic devices are not only difficult to burn, but are also required to generate less harmful gases and fumes.

As a technique for making a prepreg flame-retardant without containing a halogen element, for example, as disclosed in Patent Documents 1 to 4 and the like, a compound having a dihydrobenzoxazine ring obtained from phenols, amines and formaldehyde As a main material, inorganic flame retardants, nitrogen flame retardants, and phosphorus flame retardants can be used in combination. The flame retardant substrate has low dielectric loss tangent, low water absorption, high heat resistance, It exhibits high Tg and relatively good characteristics, and has been applied to general FR-4 applications.
JP 2002-55662 A Japanese Unexamined Patent Publication No. 7-3121 Japanese Patent Laid-Open No. 5-114784 JP-A-2-69567

  However, when the resin composition disclosed in Patent Document 1 or the like is simply applied to a prepreg, the reaction between the epoxy resin used, a polycondensate of a phenol and a compound having a triazine ring and an aldehyde However, since the change with time of the resin flow of the prepreg is increased, there is a problem that the pot life is shortened, and the application range is limited.

  In recent years, it has been required to develop a prepreg having excellent moldability and heat resistance in addition to flame retardancy.

  In view of the above, the present invention exhibits good flame retardancy, heat resistance and moldability without containing a halogen-based flame retardant, and has a longer pot life than conventional ones and can be applied to a relatively wide range of applications. An object of the present invention is to provide a curable resin composition, and a prepreg and multilayer printed wiring board using the same.

  As a result of various studies to achieve the above object, the present inventors have found that a compound having a dihydrobenzoxazine ring in the molecule, a polycondensate of a compound having a phenols and triazine ring and an aldehyde, and an epoxy resin The above-mentioned problem has been solved by a resin composition containing a specific amount of a bisphenol A type epoxy resin having a condensed phosphate ester and an inorganic filler and having an epoxy equivalent of 600 to 1500 as the epoxy resin.

  That is, the present invention is characterized by the following items (1) to (3).

  (1) 35 to 75 parts by mass of a compound having a dihydrobenzoxazine ring in the molecule, (b) phenols and (a) a total amount of 100 parts by mass of the following components (a), (b) and (c) 10 to 25 parts by mass of a polycondensate of a compound having a triazine ring and aldehydes, (c) 10 to 45 parts by mass of an epoxy resin, (d) 5 to 35 parts by mass of a condensed phosphate ester, e) The inorganic filler is contained in an amount of 30 to 100 parts by mass with respect to 100 parts by mass of the total amount of the components (a), (b), (c) and (d), and the (c) epoxy resin has an epoxy equivalent A curable resin composition characterized by containing 20 to 40% by mass of a bisphenol A-type epoxy resin having a viscosity of 600 to 1500.

  (2) A prepreg obtained by impregnating a substrate with the curable resin composition described in (1) above.

  (3) A multilayer printed wiring board comprising the prepreg as described in (2) above.

  According to the present invention, it exhibits good flame retardancy, heat resistance and moldability without containing a halogen-based flame retardant, has a longer pot life than conventional ones, and can be applied to a relatively wide range of uses. It becomes possible to provide a curable resin composition suitable as a resin composition by impregnating a no-flow prepreg, and a prepreg and multilayer printed wiring board using the same.

  The curable resin composition of the present invention comprises (a) a compound having a dihydrobenzoxazine ring in the molecule, (b) a polycondensate of a compound having phenols and triazine rings and an aldehyde, (c) an epoxy resin, and ( d) The condensed phosphate ester is 35 to 75 parts by mass, 10 to 25 parts by mass, 10 to 45 parts by mass, 5 to 5 parts by mass with respect to 100 parts by mass in total of the components (a), (b) and (c). 35 parts by mass, and (e) the inorganic filler is contained in an amount of 30 to 100 parts by mass with respect to 100 parts by mass of the total amount of the components (a), (b), (c) and (d), and (C) The epoxy resin contains 20 to 40% by mass of a bisphenol A type epoxy resin having an epoxy equivalent of 600 to 1500.

（式中、Ｒ^１はアルキル基、シクロヘキシル基、フェニル基またはアルキル基もしくはアルコキシル基で置換されたフェニル基である） The compound (a) having a dihydrobenzoxazine ring used in the present invention is not particularly limited as long as the resin has a dihydrobenzoxazine ring and is cured by a ring-opening reaction of the dihydrobenzoxazine ring. For example, as shown in the following reaction formula (1), it can be synthesized from a compound having a phenolic hydroxyl group, formalin, and a primary amine.

(Wherein R ¹ is an alkyl group, a cyclohexyl group, a phenyl group, or a phenyl group substituted with an alkyl group or an alkoxyl group)

  More specifically, with respect to the reaction formula (1), for example, a mixture of the compound having a phenolic hydroxyl group and the primary amine is added to an aldehyde such as formalin heated to 70 ° C. or higher. It can synthesize | combine by making it react at -110 degreeC, Preferably 90-100 degreeC for 20-120 minutes, and drying under reduced pressure at the temperature below 120 degreeC after that.

  Examples of the compound having a phenolic hydroxyl group include polyfunctional phenols, biphenol compounds, bisphenol compounds, trisphenol compounds, tetraphenol compounds, and phenol resins. More specifically, examples of the polyfunctional phenol include catechol, hydroquinone, resorquinol, and the like, and examples of the bisphenol compound include bisphenol A, bisphenol F and its positional isomer, bisphenol S, and the like, and a phenol resin. Examples thereof include resole resin, phenol novolac resin, phenol-modified xylene resin, alkylphenol resin, melamine phenol resin, benzoguanamine phenol resin, and phenol-modified polybutadiene. Specific examples of the primary amine include methylamine, cyclohexylamine, aniline, and substituted aniline.

  In addition, the component (a) is an organic solid content of the component (a), the component (b), and the component (c) in the composition of the present invention in consideration of the ratio in reaction of each component and the curing reactivity. Preferably it is 35-75 mass parts with respect to 100 mass parts of total amounts, More preferably, 30-70 mass parts is contained.

  The polycondensation product of the component (b) used in the present invention is not particularly limited. For example, a compound having a phenols, a triazine ring, or an aldehyde having a predetermined nitrogen content and a hydroxyl group equivalent, The reaction can be carried out under a catalyst, neutralization, washing with water, heat treatment, distillation and the like are carried out according to conventional methods, and unreacted phenols, aldehydes and solvents can be removed.

  Examples of the phenols include phenols or polyphenols such as bisphenol A and bisphenol F, alkylphenols, aminophenols, phenylphenols, and the like, which can be used alone or in combination of two or more. Further, the compound having a triazine ring is not particularly limited. And isocyanuric acid derivatives such as nurate and ethyl isocyanurate. Among these, melamine is preferable because of its good flame resistance and low cost. The amount of the compound having a triazine ring can be appropriately determined in consideration of the nitrogen content, flame retardancy, reactivity, and the like. The aldehydes are not particularly limited, but formaldehyde is generally used.

  Further, as the catalyst, a basic catalyst is preferable because the compound having a triazine ring is excellent in solubility, and amines are preferable because metals are not preferable as an electrically insulating material if a metal remains as a catalyst residue. Moreover, as a reaction solvent, since stability control becomes possible by making it react in presence in various solvents, such as acetone and methyl ethyl ketone, it is preferable. The order of the reaction is not limited, and the two main raw materials can be selectively reacted first even when all the main raw materials are simultaneously used.

  The molar ratio of the aldehydes to the phenols (aldehydes / phenols) is not particularly limited, but is preferably 0.2 to 1.5, more preferably 0.4 to 0.8. . In addition, the mass ratio of the phenols and the compound having a triazine ring is (phenols) :( compound having a triazine ring) = 10 to 98: 90-2 in consideration of both resinification and flame retardant effect. It is preferable that it is 50-95: 50-5.

  The above component (b) is a total of 100 organic solids of the components (a), (b), and (c) in the composition of the present invention, taking into account the reaction ratio and curing reactivity of each component. Preferably it is 10-25 mass parts with respect to a mass part, More preferably, 15-20 mass parts is contained.

  The component (c) epoxy resin used in the present invention includes, as a main component, phenol novolac type epoxy resin, bisphenol A novolac type epoxy resin, cresol novolac type epoxy resin, etc., in order to ensure heat resistance and flame resistance. It is preferable to use a novolac type epoxy resin.

  By the way, the polycondensate of the component (b) used as a curing agent has an amino group and has a relatively high reactivity with the epoxy resin. Therefore, when only a novolac type epoxy resin is simply used, the pot life of the prepreg is short due to the high reactivity, and the application range is greatly limited.

  Therefore, in the present invention, as the component (c), a bisphenol A type epoxy resin having low reactivity among epoxy resins is used in combination. In order to suppress the reactivity, it is preferable to use a long-chain bisphenol A type epoxy resin having a low reactive group density, but as the molecular weight of the bisphenol A type epoxy resin increases, impregnation into the prepreg during coating In order to develop the effect of suppressing the reactivity with a small amount of addition, the above-mentioned bisphenol A is liable to cause problems such as deterioration of the appearance of the prepreg and deterioration of moldability during press molding. The epoxy equivalent of the type epoxy resin is preferably 600 or more and 1500 or less.

  The addition amount of the bisphenol A type epoxy resin having an epoxy equivalent of 600 or more and 1500 or less is 20 to 40% by mass in the total amount of the (c) epoxy resin. If it is less than 20% by mass, there is not much effect in suppressing the reactivity, and if it exceeds 40% by mass, the impregnation property to the prepreg at the time of coating is lowered and the press formability is significantly reduced.

  In addition, in consideration of the reactivity and cured product characteristics of each component, the component (c) is an organic solid content of the components (a), (b) and (c) in the composition of the present invention. Preferably it is 10-45 mass parts with respect to 100 mass parts of total amounts.

（式中Ｒ_１、Ｒ_２、Ｒ_３は、各々独立にアルキル基、シクロヘキシル基等のシクロアルキル基、フェニル基等であり、ｍは１、２又は３であり、ｎは０、１又は２である。）
で表される構造を有する。このようにリン酸エステルを縮合させて高融点化したものを成分（ｄ）として組成物に配合することにより、高融点化していないものを配合した場合に生じる基板の高温耐薬品性、耐湿耐熱性、ガラス転移温度（Ｔｇ）等の低下を防ぐことができる。 The component (d) condensed phosphate used in the present invention is, for example, the following general formula (2):

(Wherein R ₁ , R ₂ and R ₃ are each independently a cycloalkyl group such as an alkyl group or a cyclohexyl group, a phenyl group, etc., m is 1, 2 or 3, and n is 0, 1 or 2) .)
It has the structure represented by these. In this way, the high melting point by condensing the phosphate ester is added to the composition as the component (d), so that the high temperature chemical resistance and moisture resistance heat resistance of the substrate generated when the non-high melting point is added. Property, glass transition temperature (Tg), and the like can be prevented from decreasing.

  In consideration of all of flame retardancy, moisture and heat resistance, and Tg, the component (d) is a total of 100 organic solids of the components (a), (b), and (c) in the composition of the present invention. Preferably it is 5-35 mass parts with respect to a mass part, More preferably, 5-20 mass parts is contained.

  As said component (e) inorganic filler used by this invention, a well-known material can be used, It does not specifically limit, It can select according to the objective to be used. Specifically, inorganic hydrates such as aluminum hydroxide, magnesium hydroxide, zeolite and hydrotalcite, clay, talc, wollastonite, mica, calcium carbonate, magnesium carbonate, alumina, silica, glass powder, etc. Inorganic fillers, zinc borate, zinc stannate, zinc hydroxystannate and other B- or Sn-based fillers, and metal oxides such as zinc oxide and tin oxide are used.

  In addition, the component (e) is preferably coated or surface-treated with a silane coupling agent, a titanate coupling agent, zinc molybdate or the like to improve adhesion with the organic component.

  The component (e) is preferably 30 to 100 masses per 100 mass parts of the total organic solid content of the components (a), (b), (c) and (d) in the composition of the present invention. Part, more preferably 40 to 80 parts by weight.

  Moreover, you may add a well-known hardening accelerator, a coupling agent, a coloring agent, antioxidant, a reducing agent, an ultraviolet opaque agent etc. to the curable resin composition of this invention as needed.

  The prepreg of the present invention is characterized in that the substrate is impregnated with the curable resin composition of the present invention, and its production method is not particularly limited. For example, the curable resin of the present invention The composition can be produced by impregnating a varnish into a substrate and heating and drying at 60 to 200 ° C. for 1 to 30 minutes.

  As the base material, known base materials used for prepregs can be used, and are not particularly limited, but are preferably woven fabric (glass cloth) using E glass, C glass, D glass, S glass and the like. More preferably, it is a glass cloth whose surface is surface-treated with a known silane coupling agent. Moreover, it is preferable that the resin content in the prepreg of this invention is 40-70 mass%.

  The multilayer printed wiring board of the present invention is, for example, a stack of a predetermined number of the prepregs of the present invention, and after arranging copper foil on both sides or one side thereof, for example, 100 to 250 ° C., 0.5 to 20 MPa at 0.2 to A copper-clad laminate is produced by heating and pressing for 5 hours, and then a printed wiring board is produced by subjecting the copper foil layer of the copper-clad laminate to circuit processing by etching or the like. It can be manufactured by laminating a prepreg or a copper clad laminate and repeating the above steps. Needless to say, a commercially available general printed wiring board can be manufactured by multilayering in the same manner as described above via the prepreg of the present invention. Moreover, you may give other well-known processes, such as a through-hole process and plating process, in manufacturing a printed wiring board.

  Hereinafter, although the present invention is explained in detail using an example, the present invention is not limited to this.

<(A) Synthesis of compound having dihydrobenzoxazine ring in molecule>
Bisphenol F (1000 g) and methanol (920 g) were added and dissolved by stirring. To this, 652 g of paraformaldehyde was added. While stirring, 930 g of aniline was added dropwise over 1 hour so that the temperature became 78 to 80 ° C. after 1 hour. After reacting for 7 hours under reflux, vacuum concentration was started at 360 mmHg. Concentration was continued while maintaining the reduced pressure, and when the pressure reached 110 ° C., the reduced pressure was set to 90 mmHg. After confirming that the effluent was gone, the resin was taken out into the vat. Thus, a thermosetting resin having a dihydrobenzoxazine ring having a softening point of 78 ° C. was obtained.

<(B) Synthesis of a polycondensation product (melamine-modified phenol resin) of a phenol and a compound having a triazine ring and an aldehyde>
29 parts by mass of 41.5% formalin and 0.47 parts by mass of triethylamine were added to 94 parts by mass of phenol, and reacted at 80 ° C. for 3 hours. After adding 19 parts by mass of melamine and further reacting for 1 hour, the temperature was raised to 120 ° C. while removing water under normal pressure, and the reaction was continued for 2 hours while maintaining the temperature. Next, the temperature was raised to 180 ° C. while removing water under normal pressure, and unreacted phenol was removed under reduced pressure to obtain a melamine-modified phenol resin having a softening point of 136 ° C.

※表中の数値は各成分の配合量（質量部）を示す。但し、かっこ内の数値は、成分（ｃ）エポキシ樹脂の総量に対する（ｃ２）の割合（質量％）を示す。また、成分（ａ）〜（ｄ）の配合量は、成分（ａ）、（ｂ）及び（ｃ）の総量１００質量部に対する量であり、成分（ｅ）の配合量は、上記成分（ａ）、（ｂ）、（ｃ）及び（ｄ）の総量１００質量部に対する量である。
※表中、成分（ａ）：上記で合成したジヒドロベンゾオキサジン環を有する熱硬化性樹脂、（ｂ）：上記で合成したメラミン変性フェノール樹脂、（ｃ１）：フェノールノボラック型エポキシ樹脂ＹＤＰＮ−６３８Ｐ（東都化成株式会社製）、（ｃ２）：ビスフェノールＡ型エポキシ樹脂ＤＥＲ−６６４（ダウケミカル製、エポキシ当量９２５ｇ／ｅｑ、常温で固体）、（ｃ３）：ビスフェノールＡ型エポキシ樹脂ＤＥＲ−６６０（ダウケミカル製、エポキシ当量４５０ｇ／ｅｑ、常温で固体）、（ｃ４）：ビスフェノールＡ型エポキシ樹脂ＤＥＲ−６６７（ダウケミカル製、エポキシ当量１８００ｇ／ｅｑ、常温で固体）、（ｃ５）：ビスフェノールＦ型エポキシ樹脂ＹＤＦ−２００４（東都化成株式会社製、エポキシ当量１０００ｇ／ｅｑ、常温で固体）、（ｄ）：縮合リン酸エステルＰＸ−２００（大八化学株式会社製）、（ｅ）：水酸化アルミニウム（電子材料用に一般的に用いられている残留イオン等の少ないもので、粒子径が３μｍ〜５μｍのもの）を表す。 <Preparation of curable resin composition varnish>
(Examples 1-3, Comparative Examples 1-4)
A resin composition with a solid content shown in Table 1 below was dissolved in methyl ethyl ketone, and adjusted with methyl ethyl ketone so that the nonvolatile content was 75%, to prepare a varnish.

* Numerical values in the table indicate the amount of each component (parts by mass). However, the numerical value in parenthesis shows the ratio (mass%) of (c2) to the total amount of component (c) epoxy resin. Moreover, the compounding quantity of component (a)-(d) is the quantity with respect to 100 mass parts of total amounts of component (a), (b) and (c), and the compounding quantity of component (e) is the said component (a ), (B), (c) and (d) with respect to a total amount of 100 parts by mass.
* In the table, component (a): thermosetting resin having a dihydrobenzoxazine ring synthesized above, (b): melamine-modified phenol resin synthesized above, (c1): phenol novolac type epoxy resin YDPN-638P ( (Toto Kasei Co., Ltd.), (c2): Bisphenol A type epoxy resin DER-664 (Dow Chemical, epoxy equivalent 925 g / eq, solid at room temperature), (c3): Bisphenol A type epoxy resin DER-660 (Dow Chemical) Manufactured, epoxy equivalent 450 g / eq, solid at normal temperature), (c4): bisphenol A type epoxy resin DER-667 (Dow Chemical, epoxy equivalent 1800 g / eq, solid at normal temperature), (c5): bisphenol F type epoxy resin YDF-2004 (manufactured by Tohto Kasei Co., Ltd., epoxy equivalent 1000 g / e , Solid at normal temperature), (d): condensed phosphate ester PX-200 (manufactured by Daihachi Chemical Co., Ltd.), (e): aluminum hydroxide (residual ions generally used for electronic materials, etc. are low With a particle diameter of 3 μm to 5 μm).

<Preparation of rigid flex printed circuit board>
The resin composition varnishes of Examples 1 to 3 and Comparative Examples 1 to 6 were respectively impregnated into the base material of IPC product number # 1080, dried and semi-cured, and the resin content was 65% and the resin flow was 3.0 ± 0. A 1% prepreg was made. In addition, the said resin part was measured based on IPC-TM-650 2.3.3.11, and the said resin flow was measured based on IPC-TM-650 2.3.17.

  On the other hand, circuit processing a copper foil layer of double-sided copper clad laminate (made by DuPont, trade name: Pilatex (registered trademark) AP8525, insulation layer thickness: 50 μm) with 18 μm copper foil laminated on both sides of a polyimide base film After that, a cover film formed by forming a layer of a polyimide-based adhesive disclosed in Japanese Patent Laid-Open No. 5-114784 is laminated on Kapton 100V (a polyimide film manufactured by DuPont, a trade name), thereby flexing the rigid-flex printed circuit board. Part was produced. In addition, a copper foil layer of a double-sided copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., trade name MCL-BE-67G (H)) having an insulating layer thickness of 0.2 mm and a copper foil thickness of 35 μm is processed into a circuit, and rigid. The rigid part of the flex printed circuit board was produced.

  Next, the flexible part and the rigid part are integrated by heating and pressurizing at a pressure of 2.9 MPa and a temperature of 190 ° C. for 90 minutes through each of the prepregs produced above, and a circuit is formed on the laminate. By processing, a rigid flex printed circuit board was obtained.

<Preparation of double-sided copper-clad laminate sample>
Two types of samples for flammability testing, one with one prepreg and another with three prepregs, are prepared, each layered with 18 μm copper foil, and heated and pressed for 100 minutes at a temperature of 185 ° C. and a pressure of 3 MPa. Thus, a double-sided copper-clad laminate sample was obtained.

<Evaluation>
The appearance, moldability, combustion resistance and resin flow of the prepreg produced above, the solder heat resistance of the double-sided copper-clad laminate, and the moldability of the rigid flex printed board were evaluated as follows. The results are shown in Table 2.
Appearance: The appearance of each prepreg was visually observed to see if there were any abnormalities.
Formability: The presence or absence of occurrence of circuit filling properties, voids and blurring was visually observed.
Combustion resistance: Two types of the double-sided copper-clad laminate samples prepared above were evaluated according to UL94.
Resin flow: The resin flow of each prepreg immediately after production and each prepreg stored in an environment of 25 ° C. and 50% RH for 1 to 3 months was measured according to the measurement method described above.
Solder heat resistance: 121 ° C., 2130 hPa pressure cooker processing apparatus after holding for 1 hour or 2 hours (double-sided copper-clad laminate sample etched product, 50 mm × 50 mm) heated to 288 ° C. The sample was immersed in a solder bath for 30 seconds, and the presence or absence of blistering and measling was observed with the naked eye. Each symbol in the table means ◯: no change, Δ: occurrence of measling or floating eyes, and x: occurrence of blistering.
-Substrate moldability: Evaluated by measuring the amount of resin oozing from the prepreg to the flexible part and the presence or absence of voids. In addition, regarding the presence or absence of a void, in addition to the substrate immediately after manufacture, the substrate stored for 1 to 3 months in an environment of 20 ° C. and 50% RH was confirmed.

  From the above results, Examples 1 to 3 in which, as (c) epoxy resin, bisphenol A type epoxy resin having an epoxy equivalent of 925, in addition to phenol novolak type epoxy resin, was used in the range of 20 to 40% by mass of the total amount of epoxy resin. The prepreg produced using the resin composition of Comparative Example 1 used in combination with a bisphenol A type epoxy resin having an epoxy equivalent of 450, Comparative Example 3 used in combination with a bisphenol F type epoxy resin, and does not use a bisphenol A type epoxy resin in combination. In comparison with the prepregs of Comparative Example 4 and Comparative Example 5 in which a bisphenol A type epoxy resin having an epoxy equivalent of 925 was used in combination of 10% by mass with respect to the total amount of the epoxy resin, the change in the resin flow with time was small. Life is significantly longer. Furthermore, it can be seen that the moldability of the rigid flex substrates of Examples 1 to 3 are superior to those of Comparative Examples 1 and 3 to 5, particularly the change with time of the presence or absence of voids.

  In addition, the prepreg of Comparative Example 2 in which a bisphenol A type epoxy resin having an epoxy equivalent of 1800 is used in combination, and the Comparative Example 6 in which a bisphenol A type epoxy resin having an epoxy equivalent of 925 is used in combination at 50% by mass with respect to the total amount of the epoxy resin are It was confirmed that the appearance and the formability were deteriorated.

Claims (3)

For a total amount of 100 parts by mass of the following components (a), (b) and (c),
(A) 35 to 75 parts by mass of a compound having a dihydrobenzoxazine ring in the molecule;
(B) 10 to 25 parts by mass of a polycondensate of a phenol and a compound having a triazine ring and an aldehyde.
(C) 10 to 45 parts by mass of an epoxy resin,
(D) 5 to 35 parts by mass of a condensed phosphate ester,
Including,
(E) 30-100 parts by mass of the inorganic filler with respect to 100 parts by mass of the total amount of the components (a), (b), (c) and (d),
Including
The curable resin composition, wherein the epoxy resin (c) contains 20 to 40% by mass of a bisphenol A type epoxy resin having an epoxy equivalent of 600 to 1500.   A prepreg comprising a substrate impregnated with the curable resin composition according to claim 1.   A multilayer printed wiring board comprising the prepreg according to claim 2.