JP2002088175A - Prepreg and laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prepreg which has excellent flame retardancy without a halogen compound, has good perforatability with laser beams, and can suitably be used for producing small, lightweight and highly integrated printed circuit boards, and to provide a laminate produced from the prepreg. SOLUTION: This prepreg characterized by impregnating an organic fiber substrate with an epoxy resin composition containing a phosphorus-modified epoxy resin. Although not containing a halogen, the prepreg has improved flame retardancy. In spite of the employment of the organic fiber substrate, excellent flame retardancy can be imparted. The punchability using laser beams can also be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepreg and a laminate used for manufacturing a printed wiring board used for electric / electronic equipment and the like.

[0002]

2. Description of the Related Art Conventionally, a prepreg is prepared by impregnating a base material such as a glass cloth with a thermosetting resin varnish obtained by dispersing an epoxy resin composition containing an epoxy resin or the like in a solvent and then heating and drying the varnish. It is made by semi-curing. Then, the required number of the prepregs are stacked, and if necessary, a metal foil such as a copper foil is stacked on one or both sides of the prepreg, and then heated and pressed to form a laminate, thereby forming a copper-clad laminate used for manufacturing a printed wiring board. Such a metal-clad laminate can be obtained.

[0003] Such prepregs and laminates use an epoxy resin composition containing a bromine-containing aromatic compound such as tetrabromobisphenol A or a halogen compound such as antimony trioxide in order to impart flame retardancy. Thus, prepregs and laminates having self-extinguishing properties, good mechanical strength, electrical characteristics, and the like have been produced.

However, since such conventional flame-retardant prepregs and laminates contain a halogen compound, when they are burned in a fire or the like, depending on the burning conditions, human bodies such as polybrominated dibenzodioxin and furan may be used. In addition, if bromine is contained in the prepreg or the laminate as described above, bromine is easily decomposed when heated, and the long-term heat resistance is poor. Was.

[0005] Therefore, prepregs and laminates that can achieve the required flame retardancy without adding a halogen compound such as bromine have been demanded. In recent years, phosphorus-modified resins and phosphorus compounds have been added. As a result, prepregs and laminates achieving flame retardancy have been provided.

On the other hand, in response to recent demands for miniaturization and weight reduction of electric and electronic devices, multilayered and highly integrated printed wiring boards have been developed, and thus printed wiring boards formed in multiple layers have been developed. In making electrical connection between the conductor layers by using through holes and via holes, it is required to reduce the diameter of these through holes and via holes. For this reason, in recent years, the insulating layer of a printed wiring board formed by prepreg is drilled by irradiating a laser beam, and the inner surface is plated or filled with a conductive paste. Through holes and via holes are increasingly being formed.

[0007]

However, since the prepreg or the laminated board made flame-retardant as described above uses a glass base material as the base material, the base material is difficult to be removed by laser light. Therefore, workability in forming through holes and via holes is poor. It is also conceivable to improve the laser workability by using organic fibers for the base material, but the organic fiber base material used conventionally has high flammability, and thus ensures the flame retardancy of prepregs and laminates It was difficult to do.

The present invention has been made in view of the above points, and has excellent flame retardancy even without containing halogen, and has good drilling workability by laser light, and is small and lightweight. It is an object of the present invention to provide a prepreg that can be suitably used for manufacturing a highly integrated printed wiring board, and a laminate manufactured using the prepreg.

[0009]

A prepreg according to the present invention is characterized in that an organic fiber base material is impregnated with an epoxy resin composition containing a phosphorus-modified epoxy resin.

The epoxy resin composition preferably contains at least one of an organic phosphorus compound and an inorganic phosphorus compound, and the content of the total amount of the organic phosphorus compound and the inorganic phosphorus compound in the epoxy resin composition Is preferably in the range of 1 to 20% by mass based on the total amount of the epoxy resin composition.

It is preferable that an inorganic filler is contained in the epoxy resin composition, and that the content is 10 to 60% by mass based on the total amount of the epoxy resin composition.

Further, it is preferable to use an aromatic polyamide nonwoven fabric as the organic fiber base material.

It is preferable that such a prepreg be subjected to a drilling process using a laser beam.

Further, a laminated plate according to the present invention is characterized by being formed by curing and molding the above prepreg.

[0015]

Embodiments of the present invention will be described below.

The epoxy resin composition used for preparing the prepreg is obtained by mixing a phosphorus-modified epoxy resin with a curing agent and a curing accelerator as required, and further includes a phosphorus compound and an inorganic filler. Is preferred. Then, a prepreg can be obtained by impregnating the organic fiber base material with such an epoxy resin and semi-curing, and a laminate can be obtained by molding the prepreg.

The phosphorus-modified epoxy resin is obtained, for example, by reacting 9,10-dihydro-9-oxa-1-phosphaphenanthrene-10-oxide with 1,4-naphthoquinone and further reacting with a cresol novolak resin. Can be used. By blending such a phosphorus-modified epoxy resin, it is possible to improve the flame retardancy of a prepreg or a laminated board without including a halogen compound in the epoxy resin composition, and furthermore, to prepare a prepreg. Excellent flame retardancy can be imparted even though an organic fiber base material is used as the base material.

In addition to the phosphorus-modified epoxy resin, another epoxy resin can be used in combination. As the epoxy resin, any epoxy resin having two or more epoxy groups in one molecule can be used without any particular limitation. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, Various types of phenol novolak type epoxy resin, bisphenol A novolak type epoxy resin, cresol novolak type epoxy resin, diaminodiphenylmethane type epoxy resin and the like can be used.

Here, the content of the phosphorus-modified epoxy resin is preferably in the range of 50 to 100% by mass based on the total amount of the epoxy resin components blended in the epoxy resin composition.

Further, in addition to the phosphorus-modified epoxy resin, an organic phosphorus compound other than the phosphorus-modified epoxy resin or an inorganic phosphorus compound can be blended. Here, as the organic phosphorus compound, a phosphate ester flame retardant (for example, ALBR)
Product name "Antiblaz" manufactured by IGHT WILSON
e1045 ") and the like. Further, as the inorganic phosphorus compound, a compound of zinc molybdate and magnesium silicate (for example, trade name “KEMGARD911C” manufactured by Sherwin Williams Japan) can be used.

These organic phosphorus compounds and inorganic phosphorus compounds can be used alone or in combination of two or more. Either the organic phosphorus compound or the inorganic phosphorus compound or both of them can be used.

When at least one of the organic phosphorus compound and the inorganic phosphorus compound is blended in the epoxy resin composition as described above, the prepreg and the laminate can have higher flame retardancy. The total amount of the organic phosphorus compound and the inorganic phosphorus compound in the epoxy resin composition is preferably in the range of 1 to 20% by mass with respect to the total amount of the epoxy resin composition excluding the solvent. When the amount is less than the range, the effect of improving the flame retardancy by blending the organic phosphorus compound or the inorganic phosphorus compound is not sufficiently exhibited, and when the blending amount exceeds this range, the glass transition temperature decreases, the adhesive property, etc. May be deteriorated.

As the curing agent for the epoxy resin,
4,4-diaminodimethylsulfone can be used, but is not particularly limited thereto. For example, amide-based curing agents such as dicyandiamide and aliphatic polyamide, and amine-based curing agents such as ammonia, triethylamine, and dimethylamine Alternatively, a phenol resin-based curing agent such as a phenol novolak resin, a cresol novolak resin, a p-xylene-novolak resin, or an acid anhydride can be used. These curing agents may be used alone or in combination of two or more. The amount of the curing agent is 0.9 to 1.1 in equivalent ratio to the epoxy resin.
It is preferable to be within the range.

The curing accelerator which can be contained in the epoxy resin varnish is not particularly limited, but tertiary amines such as triethyldiamine and benzyldimethylamine, 2-methylimidazole, 2-ethyl- Examples thereof include imidazoles such as 4-methylimidazole and 2-phenylimidazole, organic phosphines such as tributylphosphine and triphenylphosphine, and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate. Can be. These curing accelerators can be used alone or in combination of two or more. The compounding amount of this curing accelerator is preferably 0.01 to 0.5% by mass based on the total amount of the epoxy resin component.

When the inorganic filler is blended, there is no particular limitation, but inorganic powder fillers such as alumina, silica, calcium carbonate, talc, clay, barium sulfate and aluminum hydroxide, and glass fiber And fibrous fillers such as pulp fibers, aramid fibers, and ceramic fibers. These fillers may be used alone or in combination of two or more.

The amount of the inorganic filler is preferably in the range of 10 to 60% by mass based on the total amount of the epoxy resin composition excluding the solvent. In this case, the flame retardancy of the prepreg or the laminate is further improved. can do.

The epoxy resin composition having the composition as described above is preferably prepared as a resin varnish dispersed in a solvent, and then impregnated into a substrate. Examples of the solvent include amides such as N, N-dimethylformamide (DMF), ethers such as propylene glycol monobutyl ether (PC) and ethylene glycol monomethyl ether, ketones such as acetone and methyl ethyl ketone (MEK), methanol, Examples thereof include alcohols such as ethanol, aromatic hydrocarbons such as benzene and toluene, and mixtures of one or more of these solvents with 25% based on the total amount of the epoxy resin composition and the solvent. It can be blended in the range of ５０50% by mass.

On the other hand, an organic fiber substrate is used as the substrate, and an aromatic polyamide nonwoven fabric (aramid nonwoven fabric) is preferably used. As the aromatic polyamide non-woven fabric, specifically, for example, one provided as a product name “N718 # 100” manufactured by DuPont Teijin Advanced Paper Co., Ltd. can be used.

Such a base material is easily decomposed and removed when irradiated with a laser beam such as a carbon dioxide gas laser, so that it is possible to easily perform a drilling process by laser beam irradiation described later. In particular, when an aromatic polyamide nonwoven fabric is used, extremely excellent drilling workability can be obtained. Also, when an aromatic polyamide nonwoven fabric is used as the base material, since the difference in linear expansion coefficient between the aromatic polyamide and copper is small, when forming a laminate using a prepreg, lamination and integration with copper foil may be performed. In the case where a conductor circuit is formed by copper foil, copper plating, or the like, it is possible to prevent the occurrence of deformation due to heat.

The method for producing the prepreg from the epoxy resin composition and the base material is not particularly limited. For example, the above-mentioned base material may be used in a resin varnish prepared by dispersing the above epoxy resin composition in a solvent. And impregnated with the epoxy resin composition, and then heat-dried to obtain a semi-cured resin component (B-stage). When the resin component is semi-cured, for example, at 140 to 170 ° C. for 3 to
It can be dried by heating for 10 minutes. Here, the resin content in the prepreg is preferably in the range of 45 to 65% by mass.

The prepreg configured as described above may be a single prepreg, or a prepreg obtained by laminating a required number of prepregs, by arranging metal foils on one or both sides as necessary to form a laminate. The laminate is heated and pressed to integrate the laminate. Here, as the metal foil, for example, a single, alloy, or composite metal foil of copper, aluminum, brass, nickel, or the like can be used.

The heating and pressurizing conditions for laminating and integrating the laminates may be adjusted appropriately under the conditions where the epoxy resin composition is cured, and the heating and pressurizing may be performed.
~ 210 ° C, pressure 5-30MPa, heating and pressurizing time 6
Each can be set to 0 to 120 minutes.

The printed circuit board can be obtained by subjecting the thus obtained laminate to circuit formation processing by an additive method, a subtractive method or the like.

Further, a multilayer printed wiring board can be manufactured using this printed wiring board as an inner layer material. In this case, first, the circuit surface of the inner layer material on which the circuit has been formed by the additive method, the subtractive method, or the like is treated with an acid solution to perform blackening treatment.

An insulating layer is formed on one or both circuit forming surfaces of the inner layer material with a prepreg, a metal foil with resin, or an adhesive sheet, and a conductor layer is formed on the surface of the insulating layer to form a multilayer board. Is formed.

At this time, when the insulating layer is formed by the prepreg, one or more prepregs are laminated on the circuit forming surface of the inner layer material, and a metal foil is further disposed outside the prepreg. Form a laminate. The laminate is heated and pressurized and integrally molded to form a cured product of the prepreg as an insulating layer, and the outer metal foil as a conductor layer, and further apply an additive method or a subtractive method to the conductor layer. A circuit is formed by the above method to form a multilayer printed wiring board. Here, as the metal foil,
The same material as that used for the inner layer material can be used. The heat and pressure molding can be performed under the same conditions as the formation of the inner layer material.

When the insulating layer is formed of a metal foil with a resin, the metal foil with a resin is formed on the circuit forming surface of the inner layer material so that the resin layer of the metal foil with the resin faces the circuit forming surface of the inner layer material. To form a laminate. Then, by heating and pressing this laminate to integrally mold, a cured product of the resin layer of the metal foil with resin is formed as an insulating layer, and the outer metal foil is formed as a conductor layer. Circuit formation is performed by an additive method, a subtractive method, or the like to form a multilayer printed wiring board. Here, the heat and pressure molding can be performed under the same conditions as the formation of the inner layer material.

Further, by repeating the above-mentioned method using the multilayer printed wiring board thus formed as an inner layer material, a multilayer printed wiring board can be formed.

Before forming a laminate or printed wiring board by lamination molding, the prepreg is irradiated with a laser beam such as a carbon dioxide gas laser at a predetermined position according to the design mode of the laminate or printed wiring board. Irradiation and drilling can be performed.

At the time of this drilling, the semi-cured product of the epoxy resin composition constituting the prepreg is easily decomposed and removed, and the substrate made of an organic fiber substrate is also easily decomposed and removed. The drilling process can be easily performed without being hindered by the substrate. In particular, when a substrate made of an aromatic polyamide fiber is used, the laser processability is further improved.

By using the prepreg thus perforated, the ALIVH (any layer) is used.
The laminated board can be manufactured using an inner via hole) method. In this case, first, a conductive paste such as a copper paste is filled into the holes processed into the prepreg, and then, as necessary, for one prepreg or a laminate of the required number of prepregs as described above. Then, a metal foil is disposed on one or both sides to form a laminate, and the laminate is heated and pressed to form a laminate to obtain a laminate.

The printed circuit board can be obtained by subjecting the thus obtained laminate to circuit formation processing by an additive method, a subtractive method, or the like.
At this time, in the insulating layer formed by curing the resin component of the prepreg, a via hole is formed by a hole previously processed into the prepreg and a conductive paste filled in the hole, and the via hole forms the insulating layer. Are connected.

As described above, a multilayer printed wiring board can be obtained by using the printed wiring board having the conductor circuits formed on both surfaces of the insulating layer as an inner layer material. In this case, a prepreg with perforated holes and conductive paste filled into the holes is placed on one or both sides of the inner layer material, and a metal foil is placed on the outside of the prepreg as necessary. By forming, a multilayer board is formed. The outer surface of the multilayer board is subjected to a circuit forming process such as an additive method or a subtractive method.

By repeating the above-mentioned method using the multilayer printed wiring board thus formed as an inner layer material, a multilayer printed wiring board can be formed.

Further, two or more prepregs in which a hole is filled with a conductive paste and a conductive circuit is formed on both surfaces of an insulating layer are formed by laminating one or more prepregs through a hole. A multi-layer printed wiring board on which four-layer conductor circuits are formed can also be formed by interposing the wiring board and performing heat and pressure molding. Also, three or four printed wiring boards with conductor circuits formed on both sides of the insulating layer,
Alternatively, prepare more than one, and interpose one or more laminated prepregs with perforation processing and filling of holes with conductive paste between each printed wiring board, and heat-press molding. Thereby, a multilayer printed wiring board having six, eight or more conductor circuits formed thereon can be formed.

In the printed wiring board formed in this manner, the holes formed in the prepreg and the via holes formed by the conductive paste filled in the holes have IVH.
(Interstitial via hole), and the via hole does not open to the outer surface of the printed wiring board, so that the entire outer surface of the printed wiring board can be used for component mounting.

[0047]

The present invention will be described below in detail with reference to examples.

Examples 1 to 7 A four-necked glass separable flask equipped with a stirrer, a thermometer, a cooling pipe and a nitrogen gas introducing device was used as a reaction vessel. 153.5 g of -9-oxa-10-phosphaphenanthrene-10-oxide (manufactured by Sanko Chemical Co., Ltd .; product number "HCA") and toluene 400
g was heated and dissolved.

Then, 1,4-naphthoquinone 104.5
g was dividedly charged while paying attention to the reaction.

After completion of the reaction, a cresol novolak type epoxy resin (manufactured by Toto Kasei Co., Ltd .; product number "YDCN-70")
1)) Add 750 g, and inject nitrogen gas into 120
Stir at <RTIgt;

Further, triphenylphosphine was added,
The reaction was carried out at 150 ° C. for 4 hours to prepare a phosphorus-modified epoxy resin (resin A).

17.5 g of a curing agent (4,4-diaminodimethylsulfone; manufactured by Wakayama Kasei; product name "Seika Cure S") was added to this resin A, and a curing accelerator (2-ethyl-4-) was used.
0.5 g of methylimidazole).

Further, in Examples 2 to 4, 6, and 7, an organic phosphorus compound (manufactured by ALBRIGHT WILSON; product name: Antiblaze 1045) was used.
For the epoxy resin composition, an inorganic filler (aluminum hydroxide; manufactured by Sumitomo Chemical; product number "C302A") was blended so that the blending ratio with respect to the total amount of the epoxy resin composition excluding the solvent was as shown in Table 1. It was prepared in a state of being dispersed in a toluene solvent to obtain a resin varnish.

In Examples 1 to 6, this resin varnish was applied to a substrate (substrate D) made of an aramid nonwoven fabric (manufactured by Dupont Teijin Advanced Paper Co., Ltd .; product name "Surmount N-718 # 100"). About liquid crystal polyester non-woven fabric (Kuraray; product name "TRIMEX")
The base material (base material E) was impregnated and heated and dried at 160 ° C. for 5 minutes to prepare a prepreg having a resin content of 58% by mass.

Examples 8 to 10 Four-neck glass separable flasks equipped with a stirrer, a thermometer, a cooling pipe and a nitrogen gas introducing device were used as reaction vessels. 5-dihydroxyphenyl) -10H-
9-oxa-10-phosphaphenanthrene-10-
Oxide (manufactured by Sanko Chemical Co., Ltd .; product number "PHQ") 10
0g and methyl ethyl ketone 50g, biphenyl type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd .;
4000H "), and stirred at 120 ° C while filling with nitrogen gas to dissolve.

Further, triphenylphosphine was added,
The reaction was performed at 150 ° C. for 4 hours to prepare a phosphorus-modified epoxy resin (resin B).

To this resin B, 11 g of a curing agent (4,4-diaminodimethylsulfone; manufactured by Wakayama Kasei; product name "Seika Cure S") and 0.5 g of a curing accelerator (2-ethyl-4-methylimidazole) are mixed. did.

Further, in Example 9, an organic phosphorus compound (ALBRIGHT WILSON);
iblaze 1045 ") and an inorganic phosphorus compound (compound of zinc molybdate and magnesium silicate; manufactured by Sherwin Williams Japan; trade name" KEMGARD911C ") in Examples 10 and 10.
For the epoxy resin composition, an inorganic filler (aluminum hydroxide; manufactured by Sumitomo Chemical; product number "C302A") was blended so that the blending ratio with respect to the total amount of the epoxy resin composition excluding the solvent was as shown in Table 1. Was dispersed in a methyl ethyl ketone solvent to obtain a resin varnish.

This resin varnish was impregnated into a substrate (substrate F) made of aramid nonwoven fabric (manufactured by Teijin; product name: “Technola”) and dried by heating at 160 ° C. for 5 minutes to obtain a resin content of 58% by mass. A prepreg was prepared.

Comparative Example 1 A phosphorus-modified epoxy resin (resin A) was prepared in the same manner as in Examples 1 to 7, and a curing agent (4,4-diaminodimethylsulfone; manufactured by Wakayama Kasei; Seika Cure S ") 17.5 and curing accelerator (2-ethyl-4-methylimidazole) 0.5
g were mixed.

Further, an inorganic filler (aluminum hydroxide; manufactured by Sumitomo Chemical; product number "C302A") was blended so that the blending ratio with respect to the total amount of the epoxy resin composition excluding the solvent was as shown in Table 1. The composition was prepared in a state of being dispersed in a toluene solvent to obtain a resin varnish.

The resin varnish is impregnated into a substrate (substrate G) made of glass woven fabric (manufactured by Nitto Boseki; product number “116E / S136”), and dried by heating at 160 ° C. for 5 minutes to contain the resin varnish. A prepreg having a ratio of 45% by mass was prepared.

[Comparative Examples 2 and 3] A non-phosphorus-containing epoxy resin containing neither halogen nor phosphorus (manufactured by Dainippon Ink and Chemicals, Inc .; product name "EPICLON EXA-972")
3)) 100 g of a curing agent (non-phosphorus-containing phenol novolak type curing agent; manufactured by Dainippon Ink and Chemicals, Inc .; product name "EPICLON EXA-9724") 68
g and a curing accelerator (2-ethyl-4-methylimidazole) 0.1 g were mixed and dispersed in 50 g of methyl ethyl ketone as a solvent to prepare a resin varnish.

In Comparative Example 2, this resin varnish was used as a base material (base material G) made of glass woven fabric (manufactured by Nitto Boseki; product number "116E / S136"), and in Comparative Example 3, an aramid nonwoven fabric (Dupont Teijin Advanced) A prepreg having a resin content of 58% by mass was prepared by impregnating a base material (base material D) made of Paper Co .;

[Evaluation Test] Flame Retardancy Test Two prepregs obtained in each Example and Comparative Example, 8
, And 16 were laminated, copper foil with a thickness of 18 μm was placed on both sides, and heated and pressed at 200 ° C. and 30 MPa for 60 minutes.
mm, 0.8 mm and 1.6 mm double-sided copper-clad laminates were formed.

[0092] The Underwrrit is applied to this laminate.
“Test fo” by ers Laboratories
r Flammability of Plastic
A vertical burning test according to Materials-UL94 "was performed to evaluate the flame retardancy. In Table 1, the evaluation results are shown. Those that have burned are indicated by "x".

Glass transition temperature measurement DMA (dynamic viscoelasticity analysis) was carried out on a 0.8 mm-thick laminated plate molded in the same manner as in the flame retardancy test by measuring the glass transition temperature of the cured product of the epoxy resin composition. It was measured by the method.
Table 1 shows the measurement results.

Evaluation of Copper Foil Peel Strength The peel strength of the copper foil was measured in accordance with JIS C 6481 5.7 for a 0.8 mm thick laminated plate formed in the same manner as in the flame retardancy test. Table 1 shows the measurement results.

Evaluation of laser workability The prepregs obtained in each of the examples and comparative examples were subjected to a carbon dioxide gas laser in a semi-cured state, with a mask diameter of 2.1 m.
m, processing energy 24.2mJ / P, pulse width 15μ
Irradiation under the condition of s and 1 shot, diameter 100
Drilling of μm was performed. The surface roughness of the inner wall of the hole was measured with a surface roughness meter, and the difference in height of the surface irregularities was 10%.
If the particle size is less than 10 μm,
Those having a size of not more than 30 μm were evaluated as “、”, and those having a size exceeding 30 μm were evaluated as “×”. Table 1 shows the evaluation results.

[0070]

[Table 1]

The laser workability was poor in Comparative Examples 1 and 2 using glass cloth as the base material, and the flame retardancy was poor in Comparative Examples 2 and 3 using no phosphorus-modified epoxy resin. On the other hand, in Examples 1 to 10 using the organic fiber base material and the phosphorus-modified epoxy resin, both the laser workability and the flame retardancy were good.

In Examples 3, 4, 6, 7, 9, and 10 containing 1% by mass or more of an organic phosphorus compound or an inorganic phosphorus compound, the flame retardancy was particularly improved. Examples 3, 6, 7, 9, 9 and 20% by mass or less
At 0, it had a sufficiently high glass transition temperature and high copper foil peel strength. In Examples 5, 6, 8, 9, and 10 containing an inorganic filler, flame retardancy was also improved, and Examples 6, 7, 9, and 10 in which an inorganic filler and an organic or inorganic phosphorus compound were used in combination were particularly excellent. Flame retardancy was obtained.

Further, Example 1 in which an aromatic polyamide fiber nonwoven fabric (aramid fiber nonwoven fabric) was used as the organic fiber base material.
-6, 8-10, particularly excellent laser workability was obtained.

[0074]

The prepreg according to the present invention is obtained by impregnating an organic fiber base material with an epoxy resin composition containing a phosphorus-modified epoxy resin, thereby improving the flame retardancy without containing halogen. And excellent flame retardancy is imparted even though an organic fiber base material is used. Further, the drilling workability by laser can be improved.

It is preferable that the epoxy resin composition contains at least one of an organic phosphorus compound and an inorganic phosphorus compound. In this case, it is possible to obtain even higher flame retardancy. It is.

The total content of the organic phosphorus compound and the inorganic phosphorus compound in the epoxy resin composition is preferably in the range of 1 to 20% by mass based on the total amount of the epoxy resin composition. In this case, a sufficient effect of improving the flame retardancy can be obtained, and excellent adhesiveness can be obtained when the prepreg and the metal foil are laminated and integrated.

It is preferable that the epoxy resin composition contains an inorganic filler and the content is 10 to 60% by mass based on the total amount of the epoxy resin composition. It can obtain flame retardancy.

It is preferable to use an aromatic polyamide non-woven fabric as the organic fiber base material. In this case, it is possible to obtain even higher laser workability. In addition, since the difference in linear expansion coefficient between the organic fiber base material and copper is reduced, a prepreg and a copper foil are laminated and integrated to produce a laminate, or a laminate formed from the prepreg is coated with copper foil or copper. In the case where a printed circuit board is produced by forming a conductive circuit by plating, deformation of these laminated boards or printed circuit boards due to heat can be prevented.

The prepreg as described above can be perforated by a laser beam.
By doing so, the conductive paste can be filled into the holes formed in the prepreg, and the laminate can be formed by laminating or forming a printed wiring board using the laminate. In addition, a hole formed in the prepreg and a via hole formed by the conductive paste filled in the hole are formed as an IVH (interstitial via hole), and the via hole is opened on the outer surface of the printed wiring board. Thus, the entire outer surface of the printed wiring board can be used for component mounting.

The laminate according to the present invention is obtained by curing and molding the prepreg as described above.
It can improve the flame retardancy even without containing halogen, and imparts excellent flame retardancy despite the use of an organic fiber base material. Further, the drilling workability by laser can be improved.

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Claims (7)

[Claims] 1. A prepreg comprising an organic fiber base material impregnated with an epoxy resin composition containing a phosphorus-modified epoxy resin. 2. The prepreg according to claim 1, wherein the epoxy resin composition contains at least one of an organic phosphorus compound and an inorganic phosphorus compound. 3. The epoxy resin composition according to claim 2, wherein the content of the total amount of the organic phosphorus compound and the inorganic phosphorus compound is in the range of 1 to 20% by mass based on the total amount of the epoxy resin composition. The prepreg according to the above. 4. The epoxy resin composition according to claim 1, wherein an inorganic filler is contained in the epoxy resin composition, and the content is 10 to 60% by mass based on the total amount of the epoxy resin composition. The prepreg described. 5. The prepreg according to claim 1, wherein an aromatic polyamide nonwoven fabric is used as the organic fiber base material. 6. The prepreg according to claim 1, wherein the prepreg is formed by drilling with a laser beam. 7. A laminate obtained by curing and molding the prepreg according to claim 1.