JP2014065778A - Epoxy resin composition for electric wiring board, prepreg and laminated plate for electric wiring board using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition of which resin is softened at low temperature, having low viscosity, where edge face melting processing of a prepreg is easy, having good appearance without any voids, irregularities or the like, excellent handleability and high reactivity, and further given high thermostability, and to provide a prepreg and a laminated plate for an electric wiring boad using the same.SOLUTION: An epoxy resin composition contains (A) an epoxy resin having a softening point of 60°C or higher, (B) a curing agent having the softening point of 90°C or higher and containing phosphorus in the molecular structure, and (C) an epoxy resin having the softening point of 30°C or lower. Further it is preferable to contain (D) a curing agent having an aminotriazine structure in the molecular structure, (E) a phosphorus atom-containing compound of any one or more of DOPO (9,10-dihydro-9-oxa-10-phosphenanthrene-10-oxide), phosphazene, phosphate ester, and (F) a filler.

Description

  The present invention relates to an epoxy resin composition suitable for an insulating material for an electric wiring board, particularly an insulating material for a glass-based epoxy resin electric wiring board, a prepreg using the same, and a laminate for an electric wiring board.

  With the widespread use of information equipment terminals, printed wiring boards mounted on them have been reduced in size and density. In order to increase the number of layers when manufacturing them, conventionally, multiple metal foil-clad laminates were bonded using a prepreg, but drilling with a drill was necessary to achieve electrical connection in each layer. There was a limit.

  In recent years, by laminating insulating layers or insulating layers with metal layers one layer at a time on both sides of the laminated board, and repeating laser processing and wiring processing, it is possible to carry out more wiring than in the case of stacking together. Further, the mounting form has progressed from a pin insertion type to a surface mounting type, and further to an area array type represented by BGA (Ball Grit Array).

In the case of multilayering, a cyclic thermal shock resistance at a high temperature is also required, and the conventional insulating resin may cause peeling between the fiber base material and the resin. For this reason, high heat resistance is required for the substrate material.
In addition to heat resistance, the substrate material may be required to have flame retardancy for the purpose of preventing an electric fire or the like.
Conventional flame retardant resins impart flame retardancy by containing a compound containing a halogen element such as bromine, and give the molded product self-extinguishing properties. However, once such a molded article is burned in a fire or the like, toxic gases such as carbon monoxide, hydrogen cyanide, and hydrogen halide are generated, causing a great adverse effect on the human body. In addition, a compound containing a halogen compound such as bromine decomposes bromine during heating, causing a decrease in heat resistance and a decrease in reliability.
Therefore, it has been desired to develop a molded product that can exhibit flame retardancy without adding a halogen compound containing a halogen element such as bromine to the epoxy resin.

Flame retardant methods that do not use halogen compounds include flame retardants by adding organic fillers with organic compounds containing phosphorus elements, etc., and inorganic fillers such as nitrogen, silicon, and aluminum hydroxide. Flame retardants are most often used. For example, there are triphenyl phosphate (TPP) and tricresyl phosphate (TCP) which are phosphoric ester compounds. However, these are additive-type phosphorus flame retardants added to the epoxy resin and do not react with the epoxy resin, so the resulting molded product has reduced heat resistance and chemical resistance after moisture absorption. The problem of doing.
Then, the method of providing a flame retardance to a molded object was proposed, without adding a halogen compound, by reacting an epoxy resin and a phosphorus containing compound, and synthesize | combining a phosphorus containing epoxy resin. However, since DICY (dicyandiamide) is used as a curing agent, there is a problem that an amide solvent having a high boiling point such as DMF (dimethylformamide) or DMAc (dimethylacetamide) must be used. When a low boiling point solvent is used, since DICY does not dissolve, a highly hygroscopic DICY crystal is precipitated in the prepreg and contains moisture, thereby deteriorating the function of the laminate. In the case of a high-boiling solvent, when prepreg is prepared by impregnating a substrate with an epoxy resin composition varnish using DICY as a curing agent and using a high-boiling solvent such as DMF as a solvent, the prepreg is prepared. In such a case, a solvent having a high boiling point such as DMF is likely to remain, and the solvent is likely to remain in a laminated board formed using the prepreg. When the residual solvent is exposed to a high temperature such as solder reflow. The laminate has a problem that it is inferior in heat resistance because it volatilizes and breaks, and the function of the laminate is reduced.

For this reason, there is a problem that it cannot meet the required characteristics such as moisture resistance and high heat resistance which are being demanded recently, and DOPO (HCA, 9,10-dihydro-9-oxa-10-phosphaphenanthrene- When 10-oxide) or a derivative thereof is used as a curing agent, there is a problem that a pre-reaction is required from the viewpoint of improving dispersibility (see Patent Document 1).
On the other hand, by making it react with an epoxy resin using the hardening | curing agent containing phosphorus, reaction became possible, without using DICY for a hardening | curing agent. Further, since the curing agent dissolves in a solvent such as MEK (methyl ethyl ketone), it is no longer necessary to use DMAc or the like with a large environmental load (see Patent Document 2).
By this method, it became possible to impart high glass point transfer temperature and heat resistance characteristics to the thermoset (see Patent Document 3). However, since the resin is softened only at a high temperature and the viscosity is high, the laminated plate When preparing a prepreg as a material, the appearance of the prepreg is likely to deteriorate, and a high temperature is required in the surface treatment to partially melt the resin surface of the prepreg cut surface by heat in order to prevent powder falling off from the prepreg. There was a problem that could not be implemented. In addition, when processing to a prepreg is necessary at the time of use (lamination processing or the like), a high temperature is required to melt and bond the surface, which has been a problem.

JP 2001-131393 A JP 2002-265562 A JP 2012-012589 A

  The present invention has been made to solve the above problems, the resin is softened at a low temperature, the viscosity is low and the end face melting process of the prepreg is easy, and there is no void, unevenness, etc., and the appearance is good. The present invention provides an epoxy resin composition excellent in handleability, high reactivity, and imparted with high heat resistance, a prepreg using the epoxy resin composition, and a laminate for an electric wiring board.

The present invention provides [1] (A) an epoxy resin having a softening point of 60 ° C. or higher, (B) a curing agent having a softening point of 90 ° C. or higher and containing a phosphorus atom in the molecular structure, and (C) a softening point of 30 ° C. The present invention relates to an epoxy resin composition containing the following epoxy resin.
Moreover, this invention relates to the epoxy resin composition as described in said [1] whose [2] (A) epoxy group equivalent of the epoxy resin whose softening point is 60 degreeC or more is 300 g / eq or less.
The present invention also relates to [3] the epoxy resin composition according to [1] or [2], further including (D) a curing agent having an aminotriazine structure in the molecular structure.
[4] The present invention further includes [4] the above-mentioned [E] further including any one or more of DOPO (9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide), phosphazene, and phosphate ester. It relates to the epoxy resin composition according to any one of [1] to [3].
Moreover, this invention relates to the epoxy resin composition in any one of said [1]-[4] containing [5] filler (F) further.
Moreover, this invention is any one of said [1]-[5] which contains 0.5-35 mass% of (C) with respect to the total mass of (A)-(E) except [6] (F). It relates to the epoxy resin composition described in 1.
Moreover, this invention is described in any one of said [1]-[6] which contains 35-60 mass% of (A) with respect to the total mass of (A)-(E) except [7] (F). It relates to an epoxy resin composition.
Moreover, this invention is described in any one of said [1]-[7] which contains 20-55 mass% of (B) with respect to the total mass of (A)-(E) except [8] (F). It relates to an epoxy resin composition.
Moreover, this invention is described in any one of said [1]-[8] whose content of the phosphorus atom in the epoxy resin composition except [9] (F) is 0.2-5 mass%. The present invention relates to an epoxy resin composition.

And this invention makes viscoelasticity the epoxy resin composition powder obtained from the prepreg obtained by making the epoxy resin composition in any one of said [1]-[9] combined with a [10] base material. The present invention relates to a prepreg having a melting start temperature of 100 ° C. or lower, a minimum melting temperature of 115 to 140 ° C., and a minimum melt viscosity of 1000 to 3000 Pa · s when measured with a measuring device.
The present invention also provides [11] an electricity obtained by laminating one or more prepregs according to the above [10], or laminating one or more prepregs, and further laminating a metal foil on at least one surface and heating and pressing. The present invention relates to a laminated board for wiring boards.

  (A) an epoxy resin having a softening point of 60 ° C. or higher, (B) a curing agent having a softening point of 90 ° C. or higher and containing phosphorus in the molecular structure, and (C) an epoxy resin having a softening point of 30 ° C. or lower. By using the resin composition, the melting start temperature of the prepreg using the resin composition is 100 ° C. or lower, the minimum melting temperature is 115 to 140 ° C., and the minimum melt viscosity at that time is as low as 1000 to 3000 Pa · s. . A prepreg using this is easy to melt at the end of the prepreg because the resin is softened at a low temperature, and a prepreg having a good appearance without voids, irregularities, etc. is obtained, and flame retardancy, solder heat resistance, etc. A laminate material having excellent heat resistance can be obtained.

[Epoxy resin composition]
The epoxy resin composition according to the present invention comprises (A) an epoxy resin having a softening point of 60 ° C. or higher, (C) an epoxy resin having a softening point of 30 ° C. or lower, and (B) a molecular structure having a softening point of 90 ° C. or higher. Contains a phosphorus-containing curing agent containing a phosphorus atom.
Further, (D) a curing agent having an aminotriazine structure in the molecular structure, and (E) DOPO (9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide), phosphazene, phosphate ester as a flame retardant component It relates to a wiring board material containing a flame retardant containing any one or more of (F) filler.

  The prepreg obtained from this epoxy resin composition has no defects (pinholes, irregularities, etc.), is suitable for processing that involves melting of the resin (end melting treatment), and a metal foil-clad laminate using the prepreg. The laminate is excellent in heat resistance and flame retardancy.

“(A) Epoxy resin with softening point of 60 ° C. or higher”
(A) An epoxy resin having a softening point of 60 ° C. or higher is an epoxy resin having a phenol novolac type epoxy structure or a cresol novolac type epoxy structure as a repeating unit in the molecular structure and having two or more repeating units. The softening point is JIS The measurement was performed according to standard K-7234 (epoxy resin softening point test method, ring and ball method).
The commercially available products are not limited to the following examples. For example, N-690-75M (epoxy group equivalent 215 g / eq, softening point 90 ° C.) which is a cresol novolac type epoxy resin manufactured by DIC Corporation. N-673-80M (epoxy group equivalent 212 g / eq, softening point 73 ° C.), YDCN-704 (epoxy group equivalent 210 g / eq, softening point), an o-cresol novolac type epoxy resin manufactured by Nippon Steel Chemical Co., Ltd. 90 ° C.), YDCN-700-7 (epoxy group equivalent 200 g / eq, softening point 73 ° C.) and the like.
In the present invention, (A) the number of parts of the epoxy resin having a softening point of 60 ° C. or higher is 100% by mass of the total resin solid mass of (A) to (E) excluding (F) filler and diluent solvent. In this case, 35 to 60% by mass is preferable, 38 to 55% by mass is more preferable, and 40 to 53% by mass is particularly preferable.

[(B) Curing agent having a softening point of 90 ° C. or higher and containing a phosphorus atom in the molecular structure]
(B) As the phosphorus-containing curing agent, DOPO (HCA, 9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide) or a phenolic hydroxyl group such as phenol novolak or cresol novolak in an organic group thereof Is a curing agent obtained by polymerizing (reacting) a resin having a repeating unit as a repeating unit.
Regarding the binding site, DOPO (HCA) is a phosphorus atom in the molecular structure, and the resin to be polymerized is a covalent bond (C═C bond) in the molecular structure.
In the present invention, the hydroxyl equivalent of the (B) phosphorus-containing curing agent is preferably 80 to 800 g / eq, more preferably 100 to 400 g / eq, and particularly preferably 140 to 250 g / eq. The phosphorus atom content is preferably 1 to 15% by mass, more preferably 2 to 9% by mass, and particularly preferably 3 to 5% by mass.
(B) The number of parts of the curing agent having a softening point of 90 ° C. or higher and containing a phosphorus atom in the molecular structure is the sum of the resin solid masses of (A) to (E) excluding (F) filler and diluent solvent. When it is 100 mass%, 20-55 mass% is preferable, 30-50 mass% is more preferable, and 35-45 mass% is especially preferable.

“(C) Epoxy resin with a softening point of 30 ° C. or lower”
(C) The epoxy resin having a softening point of 30 ° C. or lower is an epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, or epoxidized polybutadiene, and preferably exhibits a liquid property at room temperature (25 ° C.). It is a thing.
Examples of commercially available products include, but are not limited to, 830S (epoxy group equivalent 168 g / eq), a bisphenol F type liquid epoxy resin manufactured by DIC Corporation, manufactured by Nippon Steel Chemical Co., Ltd. YDF-170 (epoxy group equivalent 170 g / eq) which is a bisphenol F type liquid epoxy resin, PB3600 (epoxy group equivalent 200 g / eq) which is an epoxidized polybutadiene manufactured by Daicel Chemical Industries, Ltd., and the like.
(C) The number of parts of the epoxy resin having a softening point of 30 ° C. or less is (F) When the total resin solid mass of (A) to (E) excluding the filler and the dilution solvent is 100% by mass, 0.5 to 35% by mass is preferable, 4.5 to 30% by mass is more preferable, and 8 to 22% by mass is particularly preferable.

“(D) Curing agent having aminotriazine structure in molecular structure”
(D) The curing agent containing an aminotriazine structure in the molecular structure is a phenol novolac resin or cresol novolac resin having an aminotriazine structure in the molecular structure, preferably containing 7 to 25% by mass of nitrogen atoms. The thing that is. Although not limited to the following examples, for example, melamine-modified phenol novolac resin, melamine-modified cresol novolak resin, and the like can be mentioned.
Examples of commercially available products include, but are not limited to, for example, LA-7052 (hydroxyl equivalent: 120 g / eq, nitrogen content: 8% by mass) which is an aminotriazine-modified novolak resin manufactured by DIC Corporation. LA-7054 (hydroxyl equivalent: 125 g / eq, nitrogen content: 12% by mass). In the present invention, the nitrogen content derived from the aminotriazine structure in the resin mixture excluding (F) filler (filler) is 0.1 to 0.1 by blending (D) a curing agent having an aminotriazine structure in the molecular structure. It is preferably 3% by mass, more preferably 0.2-2% by mass, and particularly preferably 0.3-1% by mass.

“(E) Flame retardant components”
The flame retardant imparting agent used in the present invention is one or more phosphorus compounds of DOPO (9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide), phosphazene, and phosphate ester, (E) It is preferable that the phosphorus atom content rate as a flame-retardant component is 8 mass% or more and 25 mass% or less.
As such a phosphorus compound, a commercially available compound can be used, and is not limited to the following examples. For example, PX-200 (1,3-phenylenebis (di-2,6-xylenyl) phosphate, Daihachi Chemical Industry Co., Ltd., phosphorus atom content 9.1 mass%), HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, Sanko Chemical Co., Ltd., phosphorus Atom content 14.3 mass%) and SPB-100 (polydiphenoxyphosphazene, Otsuka Chemical Co., Ltd. phosphorus atom content 13 mass%). In addition, phosphorus compounds having a phosphorus atom content of 20 to 25% by mass or more such as phosphinates and diphosphinates can be used in combination.
In the present invention, it is preferable that the phosphorus atom content (content) in the resin mixture excluding (F) filler (filler) is 0.2 to 5% by mass by addition or blending of the flame retardant component, and further 0 0.8 to 4% by mass is preferable, and 1.5 to 2.6% by mass is particularly preferable.

  “(B) phosphorus-containing curing agent”, “(A), (C) epoxy resin”, “(D) curing agent including aminotriazine structure in molecular structure”, “(E) flame retardant component” A curing accelerator, a colorant, an antioxidant, a reducing agent, an ultraviolet opaque agent, and the like can be added to the epoxy resin composition to be contained, if necessary, within the intended range. Further, the filler (F) may be added to such an extent that the punching workability, drilling workability and dielectric properties are not deteriorated. Examples of the filler (F) include talc, mica, silica, glass, aluminum hydroxide, and magnesium hydroxide.

  The epoxy resin composition varnish obtained by blending the above (A), (B), (C), (D), (E), and (F) in a solvent is applied to a substrate such as a glass woven fabric or a glass nonwoven fabric. A prepreg can be obtained by impregnation, drying, and B-stage.

  Examples of the solvent include, but are not limited to, the following examples: methyl ethyl ketone, acetone, ethylene glycol monomethyl ether, benzene, toluene, and the like.

  The prepreg of the present invention can be obtained by impregnating or applying the above-described epoxy resin composition varnish to a substrate and drying, and is manufactured by semi-curing (B-stage) by heating at the time of drying or the like. As a base material, as a woven fabric base material, a natural fiber base material such as paper and cotton linter, an organic synthetic fiber base material such as aramid, polyvinyl alcohol, polyester and acrylic, an inorganic fiber base material such as glass and asbestos Is mentioned. From the viewpoint of flame resistance, a glass fiber substrate (glass cloth or the like) is preferable. Glass fiber base materials (glass cloth, etc.) include woven fabrics using E glass, C glass, D glass, S glass, etc., glass woven fabrics obtained by bonding short fibers with an organic binder, and glass fibers and cellulose fibers. A glass woven fabric using E glass is more preferable.

The thickness of the substrate is not particularly limited, and for example, about 0.03 to 0.5 mm can be used. The amount of the resin composition attached to the substrate is the resin content of the prepreg after drying. After impregnating or coating the substrate so as to be 20 to 90% by mass, it is usually heat-dried at a temperature of 100 to 200 ° C. for 1 to 30 minutes and semi-cured (B-stage).
Through the above steps, the prepreg of the present invention can be obtained.
The prepreg obtained using the epoxy resin composition of the present invention is obtained by measuring the epoxy resin composition powder collected from the prepreg obtained by combining the epoxy resin composition with a base material with a viscoelasticity measuring device (eg, rheometer). When measured, the melting start temperature is 100 ° C. or less, the lowest melting temperature at which the viscosity is lowest is 115 to 140 ° C., and the lowest melting viscosity at that time is 1000 to 3000 Pa · s. To collect the epoxy resin composition powder from the prepreg, put the prepreg in a plastic bag, loosen it together with the bag, take out the epoxy resin composition powder from the base material, and pass it through a 100 mesh sieve. Was used as a sample.
Using a viscoelasticity measuring device (rheometer, manufactured by TA Instruments Japan Co., Ltd., AR2000ex), a heating rate of 2.0 ° C./min, a period of 1 Hz, a displacement of 5%, and a plate diameter of 20 mm is 20 to 20 mm. Measurement of the melting start temperature, the minimum melting temperature, and the minimum melt viscosity was performed between temperatures of 200 ° C. At this time, the sample was measured using 0.5 g.

  The laminated board of the present invention can be produced by laminating a predetermined number of sheets using the aforementioned prepreg. Moreover, a metal foil clad laminated board can be manufactured by carrying out the lamination | stacking shaping | molding of the prepreg of this invention in the structure which piled 1-20 sheets, for example, and arrange | positioned metal foil, such as copper and aluminum, on the single side | surface or both surfaces. The metal foil is not particularly limited as long as it is used for electrical insulating material applications. The molding conditions may be, for example, a laminated plate for an electrical insulating material and a multilayer plate. For example, a multistage press, a multistage vacuum press, continuous molding, an autoclave molding machine or the like is used, and the temperature is 100 to 250 ° C. and the pressure is 0. It can be molded in a range of 2 to 10 MPa and a heating time of 0.1 to 5 hours. Further, the prepreg of the present invention and the inner layer wiring board can be combined and laminated to produce a multilayer board.

Experimental Example [(B) Synthesis of Curing Agent (Phosphorus-Containing Curing Agent B) with a Softening Point of 90 ° C. or More and a Phosphorus Atom in the Molecular Structure]
In carrying out the present invention, a phosphorus-containing curing agent was synthesized as follows.
In a flask equipped with a thermometer, condenser, fractionator, nitrogen gas inlet, and stirrer, 192.4 g (1.85 mol) of phenol novolac resin, 68.0 g (0.50 mol) of p-anisaldehyde and 9 , 10-dihydro-9-oxa-10-phosphaphenatrene-10-oxide (DOPO (HCA)) 108.0 g (0.50 mol), heated to 180 ° C. and reacted at 180 ° C. for 8 hours. Then, water was removed under reduced pressure by heating to synthesize a phenol novolac resin (B) which is a curing agent having a softening point of 90 ° C. or higher and containing phosphorus in the molecular structure. This phenol novolac resin had a softening point of 125 ° C. (R & B method (ring & ball)), a hydroxyl group equivalent of 190 g / eq., And a phosphorus atom content of 4.2 mass%.

Examples 1 and 2 and Comparative Examples 1 to 3
Using the materials shown in Table 1, except silica and aluminum hydroxide were dissolved in methyl ethyl ketone, silica and aluminum hydroxide were added, and a varnish having a nonvolatile content of 69% by mass was produced. This varnish was impregnated into a glass woven fabric (thickness 70 μm, basis weight 83 g / m ² ) so as to have a resin content of 54% by mass, dried and a prepreg (phosphorus atom content relative to the solid content excluding the filler; 1: 1.9% by mass), (Example 2: 2.0% by mass), (Comparative Example 1: 2.0% by mass), (Comparative Example 2: 2.0% by mass), (Comparative Example 3: 1.43 mass%)) was obtained. Three prepregs were formed, 18 μm copper foil was disposed on both sides thereof, and press-molded at 180 ° C. for 60 minutes at 2.5 MPa to obtain a copper-clad laminate having a thickness of 0.29 mm.

  The materials used are summarized in Table 2.

[Appearance observation]
The copper foil of the copper-clad laminate obtained above is removed by etching, and observed using a stereomicroscope (Nikon Corporation). Voids with a diameter of 50 μm or more and 2500 μm or less in 2500 μm × 2500 μm per place. Those having 10 or less were evaluated as good appearance (◯), and those exceeding 15 were evaluated as defective (×). Observed spots were randomly observed at five places.

[Heat resistance]
(Solder heat resistance)
A solder heat resistance test was performed using a solder bath, a thermometer (HFT-60E manufactured by Anritsu Keiki Co., Ltd.), and a stopwatch in accordance with JIS standard 6481. A copper clad laminate cut to 50 mm × 50 mm was floated on the solder adjusted to 288 ° C. using a thermometer with the copper foil remaining on both sides, and the sample was measured immediately after floating on the solder. The test time was 30 minutes, and the sample was taken out after 30 minutes had passed immediately after the sample was floated on the solder. Thereafter, the sample was observed, and evaluation was made with (◯) indicating that no peeling occurred between the copper foil and the base material or between the base material and the base material, and (x) indicating the other.

(T-300 test)
Immediately after TMA (Thermo-mechanical analysis, TA Instruments Japan Co., Ltd.) was used to set the gas phase at 300 ° C, measure the time until delamination occurred, and the temperature in the tank reached 300 ° C Observe until 60 min. The case where no delamination occurred was evaluated as (◯), and the others were evaluated as (×).

(Flame retardance)
The test was conducted by a method that complies with UL94 standards and the Electrical Appliance and Material Control Law technical standards.
For the sample, remove all copper foil by etching the copper-clad laminate, cut it into a specified size (length 125mm, width 12.7mm) with a diamond cutter, immediately wash it with running water for 3min, and blow it at 80 ° C. The test was carried out within 30 min after completion of drying. The test results are shown in accordance with the notation method of UL94.

(Viscoelasticity measurement)
Using a viscoelasticity measuring device (rheometer, manufactured by TA Instruments Japan Co., Ltd., AR2000ex), a heating rate of 2.0 ° C./min, a period of 1 Hz, a displacement of 5%, and a plate diameter of 20 mm is 20 to 20 mm. Measurement of the melting start temperature, the minimum melting temperature, and the minimum melt viscosity was performed between temperatures of 200 ° C. The curing time of the prepreg used as a sample at this time was about 140 sec, and the measured mass was 0.5 g using a powder obtained by passing the resin composition powder dropped through the prepreg with a 100-mesh sieve.
The above measurements and evaluation results of Examples 1 and 2 and Comparative Examples 1 to 3 are summarized in Table 3.

In Comparative Example 1 where the epoxy resin of (A) and the curing agent of (B) are used and (C) the epoxy resin having a softening point of 30 ° C. or lower is not used, the melting start temperature of the prepreg powder is as high as 110 ° C. Since the minimum melt viscosity is also high, there are many voids in the laminate and the appearance deteriorates. Further, in Comparative Example 2 in which the softening point of (A) is lower than that in Comparative Example 1, the minimum melt viscosity is high and the laminate has many voids, resulting in poor appearance. Further, even when the epoxy resins (A) and (C) are used, the comparative example 3 using the novolak resin as the curing agent without using the curing agent containing the phosphorus atom (B), the solder heat resistance and T- The heat resistance at 300 ° C. in the gas phase of the 300 laminate is inferior.
On the other hand, Example 1 using (A) epoxy resin (softening point 60 ° C. or higher), (B) a curing agent containing phosphorus atoms, and (C) epoxy resin (softening point 30 ° C. or lower), In No. 2, a laminated board having a good appearance with no voids or the like having a melting start temperature of the prepreg powder of 100 ° C. or lower and a low minimum melt viscosity is obtained. Moreover, the solder heat resistance and the gas phase heat resistance at 300 ° C. are good, and the flame retardancy is also excellent. Furthermore, since the melting start temperature of the prepreg powder is low, it is easy to melt the end surface of the prepreg, and a prepreg having a good appearance without voids and irregularities can be obtained. By using this, a laminate without voids can be obtained. Can do.

Claims (11)

  (A) An epoxy resin having a softening point of 60 ° C. or higher, (B) a curing agent having a softening point of 90 ° C. or higher and containing a phosphorus atom in the molecular structure, and (C) an epoxy resin having a softening point of 30 ° C. or lower. Epoxy resin composition.   2. The epoxy resin composition according to claim 1, wherein an epoxy group equivalent of the epoxy resin having a softening point of 60 ° C. or higher is 300 g / eq or less.   The epoxy resin composition according to claim 1 or 2, further comprising (D) a curing agent having an aminotriazine structure in the molecular structure.   Furthermore, (E) DOPO (9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide), a phosphazene, and any one or more of phosphate ester are included in any one of Claims 1-3. Epoxy resin composition.   Furthermore, the epoxy resin composition in any one of Claims 1-4 containing (F) filler.   The epoxy resin composition according to any one of claims 1 to 5, comprising 0.5 to 35% by mass of (C) based on the total mass of (A) to (E) excluding (F).   The epoxy resin composition according to any one of claims 1 to 6, comprising 35 to 60% by mass of (A) based on the total mass of (A) to (E) excluding (F).   The epoxy resin composition according to any one of claims 1 to 7, which contains 20 to 55 mass% of (B) with respect to the total mass of (A) to (E) excluding (F).   Content of the phosphorus atom in the epoxy resin composition except (F) is 0.2-5 mass%, The epoxy resin composition in any one of Claims 1-8.   When the epoxy resin composition powder obtained from the prepreg obtained by combining the epoxy resin composition according to any one of claims 1 to 9 on a substrate is measured with a viscoelasticity measuring device, the temperature at the start of melting is A prepreg that is 100 ° C. or lower, has a minimum melt temperature of 115 to 140 ° C., and a minimum melt viscosity of 1000 to 3000 Pa · s.   A laminate for an electrical wiring board obtained by laminating one or more prepregs according to claim 10 or laminating one or more prepregs, further laminating a metal foil on at least one surface thereof, and heating and pressing.