JP2001234494A - Nonwoven fabric for laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the solvent-resistant strength of a sheet obtained by curing nonwoven fabric for a laminate and the soldering heat resistance of a printed circuit board or insulated board produced from the nonwoven fabric sheet, and simultaneously improve the initial strength expression of the nonwoven fabric sheet. SOLUTION: This nonwoven fabric for the laminate, comprising 80 to 97 wt.% of fibers and 20 to 3 wt.% of a binder resin for binding the fibers to each other, characterized by having the following characteristics (1) to (4): (1) the binder resin contains a main agent and a curing agent as main components; (2) the main agent of the binder resin comprises 90 to 30 wt.% of an orthocresol novolak type epoxy resin and 10 to 70 wt.% of a high mol.wt. epoxy resin having a mol.wt. of 3,000 to 100,000; (3) the curing agent is an active hydrogen-containing compound; and (4) the ratio of the total amount of the mole number of glycidyl groups in the binder resin to the total amount of the mole number of the active hydrogen atoms in the curing agent is 100:200 to 100:100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-woven fabric for a laminated board requiring solder heat resistance, and more particularly to a non-woven fabric for a laminated board used for a printed wiring board, an insulating board and the like.

[0002]

2. Description of the Related Art Nonwoven fabrics usually used for printed wiring boards and insulating boards are made of inorganic fibers such as glass and ceramics or organic fibers such as tetron, aramid and fluorine by a wet method or a dry method, and a binder is added to the sheets. Add, dry and cure to a non-woven fabric. As the binder, self-crosslinkable acrylic resin, epoxy resin,
Phenolic resins, water-soluble silicone resins, etc. are conceivable, but epoxy resins have good properties in evaluation of heat resistance, mechanical strength, electrical insulation, etc. after lamination, and are widely used for this reason. It is used for

Among these epoxy binders that can be used for nonwoven fabrics, carboxy-modified epoxy resins, bisphenol A epoxy resins, and ortho-cresol novolak epoxy resins are highly useful because they are relatively easily available and inexpensive. Resins.

[0004] The carboxy-modified epoxy resin refers to a resin in which an acrylic vinyl copolymer is introduced into a main chain epoxy resin, and a carboxyl group is bonded to the vinyl copolymer. It is a general term that includes notations such as resin and carboxy-modified acrylate resin. The first feature of the carboxy-modified epoxy resin is that it has a self-emulsifying property, and since it does not use an emulsifier, it is advantageous in electrical insulation.
The second characteristic is that the curing reaction is very fast, so that it is suitable for use as a nonwoven fabric binder which requires immediate curing.

[0005] Bisphenol A type epoxy resin and ortho-cresol novolak type epoxy resin are resins which are often used as matrix resin for electric insulation. Although inferior in comparison, the chemical structure is closer to the matrix resin than the carboxy-modified epoxy resin, so it has similarity in compatibility (adhesion of the interface between the binder resin and the matrix resin) and thermal expansion coefficient,
Cracks due to the difference in the coefficient of thermal expansion between the fiber and the matrix resin during heating are unlikely to occur.

Orthocresol novolak type epoxy resins have a polyfunctional structure characteristic of novolak type compared to bisphenol A type epoxy resins, so that the crosslink density can be made relatively high. As a result, ortho-cresol novolak type epoxy resins have high heat resistance of cured products and excellent adhesiveness, and are therefore used in applications requiring heat resistance such as matrix resins and sealing materials. Also, compared with phenol novolak type epoxy resin, it has a higher softening temperature and excellent moisture resistance.

On the other hand, as a curing agent used for these epoxy resins for nonwoven fabrics, amine type, phenol type, epoxy type, isocyanate type, inorganic / organic / acid anhydride type, mercaptan type, etc. can be used. Specifically, melamine-based resins, dicyandiamide, polyhydric phenols, aliphatic and aromatic amines, and the like are widely used.

However, when these epoxy resins and curing agents are used as binders, the stability of the papermaking process of the nonwoven fabric (immediate curability is required) and the stability of the matrix resin varnish impregnation process (resistance after curing). However, none satisfy the requirements of the solvent strength (which is required for solvent strength) and the solder heat resistance of the laminated board (for which low water absorption, interfacial adhesive strength and balanced thermal expansion are required).

The carboxy-modified epoxy resin is quick-curing, so that it has the effect of quickly developing strength during papermaking and having excellent papermaking stability, and has a strong solvent resistance when impregnating a matrix resin. Due to the hydrophilicity, the water absorption after molding the laminate is increased as compared with the case where another resin is used. As a result, in the solder heat resistance test of the laminate, there is a problem that swelling occurs in the solder bath even in a short period of water absorption treatment.

On the other hand, the bisphenol A type epoxy resin is better in terms of water absorption than the carboxy-modified resin, but the curing speed of the resin is very slow, so that the continuous operation in the nonwoven fabric making process is slow and the productivity is inferior. In addition, the nonwoven fabric after papermaking has insufficient solvent resistance at the time of impregnation with the matrix resin varnish, so that additional curing may be required, which increases the number of steps. Further, even in a solder heat resistance test of the laminate, a resin having a low heat resistance has not been obtained sufficiently.

On the other hand, those using orthocresol novolak type epoxy resin as a binder are excellent in solvent resistance of a nonwoven fabric sheet, solder heat resistance of a laminate, and low water absorption. Therefore, good properties can be expected by using an ortho-cresol novolak type epoxy resin as a binder resin for a nonwoven fabric for electrical insulation.

However, when an orthocresol novolac type epoxy resin binder non-woven fabric is actually formed, the reaction speed of the binder resin is slow, so that the process strength in the first half of the paper machine drying zone is weak, and sheet breakage is very likely to occur. Failure occurs. This is because the curing rate in the papermaking process of the nonwoven fabric is low. To solve this, it is important to increase the reaction rate of the binder resin, but at the same time, the solvent resistance after curing must not decrease (maintaining the operation stability of the matrix resin varnish impregnation step). The interfacial adhesive strength between the binder resin and the matrix resin must not decrease (maintaining solder heat resistance),
Additional conditions are required, such as that the water absorption must not be high (maintaining solder heat resistance, electrical insulation, and long-term reliability).

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a binder resin used for a non-woven fabric for a laminated board, which relates to a solvent-resistant sheet of a non-woven fabric sheet containing an ortho-cresol novolak type epoxy resin as a main component after curing. An object of the present invention is to improve the initial strength of a nonwoven fabric sheet while maintaining the solder heat resistance of a printed wiring board or an insulating board using the same.

[0014]

The inventor of the present invention uses an ortho-cresol novolak type epoxy resin as an epoxy resin in combination with a high molecular weight epoxy resin having a molecular weight of 3,000 to 100,000, and uses a compound having active hydrogen as a curing agent. Solved this problem.

According to a first aspect of the present invention, there is provided a fiber having a content of 80 to 97% by weight.
And a binder resin for bonding fibers to each other, and 20 to 3% by weight of the laminate, wherein (1) the binder resin has a main component and a curing agent as main components, and (2) the binder resin has an orthocresol novolak as a main component. Type epoxy resin 90 ~
High molecular weight epoxy resin with 30% by weight and molecular weight of 3,000 to 100,000
(3) the curing agent is a compound having active hydrogen, and (4) the total number of moles of glycidyl groups in the binder resin and the total number of moles of active hydrogen in the curing agent. The present invention relates to a nonwoven fabric for a laminate, wherein the ratio is in the range of 100: 20 to 100: 100.

According to a second aspect of the present invention, in the first aspect, the curing agent in the binder resin is one or more selected from an amine compound, a phenol compound, a mercaptan compound, and an organic acid compound. The present invention relates to a nonwoven fabric for a laminate, which is two or more compounds. A third invention of the present invention relates to a printed wiring board or an insulating board made from the nonwoven fabric for a laminate described in the first or second invention.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the present specification, the term "binder resin" means a resin containing a main agent and a curing agent as main components, and if necessary, a combined curing agent, a coupling agent, a curing accelerator and the like. In the present specification, "the number of moles of glycidyl group"
It refers to the total number of moles of glycidyl groups of the orthocresol novolak type epoxy resin and other epoxy resins having glycidyl groups in the “binder resin”. In the present specification, “all epoxy resins” refers to a total of orthocresol novolak type epoxy resins and other epoxy resins having a glycidyl group.

In the present invention, an ortho-cresol novolak type epoxy resin and a high molecular weight epoxy resin having a molecular weight of 3,000 to 100,000 are used as main components of a binder resin for binding fibers.

The ortho-cresol novolak type epoxy resin is excellent in chemical resistance and heat resistance, and has good reactivity at high temperatures, and is therefore a resin used for epoxy powder coatings, molded articles, laminates and the like. In the present invention, an ortho-cresol novolak type epoxy resin having a high Tg is used. However, since the use of this resin has many functional groups in the main skeleton of the binder resin, physical properties excellent in reactivity and adhesiveness can be realized.

The orthocresol novolak type epoxy resin in the present invention is 100% by weight of the total of the orthocresol novolak type epoxy resin and the high molecular weight epoxy resin having a molecular weight of 3,000 to 100,000 in order to maintain the adhesiveness with the matrix resin. , It is desirable to contain 90 to 30% by weight. If the amount of the ortho-cresol novolac epoxy resin is less than the lower limit, a sufficient cross-linking density after curing cannot be obtained, and strength (solvent resistance), solder heat resistance and water absorption deteriorate, which is not preferable. When the amount of the orthocresol novolak type epoxy resin exceeds the upper limit, the amount of the high molecular weight epoxy resin is relatively reduced, so that the film forming property of the binder resin in the first half of the paper machine drying zone cannot be increased, and the process strength is reduced. (Initial expression intensity) is not preferred because it decreases. Alternatively, it is conceivable to take a long time for the curing reaction because the development of the strength of the binder resin becomes slow. However, in a continuous operation for obtaining a sufficient strength, the speed becomes low and the productivity is reduced.

In the present invention, a molecular weight of 3,000 to 1 used by mixing with an orthocresol novolak type epoxy resin is used.
Since the high molecular weight epoxy resin of 100,000 has a film forming property as a high molecular weight component in the drying curing process of the binder resin from the beginning, it has an effect of increasing the process strength (initial development strength) in the first half of the paper machine drying zone. .

The high molecular weight epoxy resin used in the present invention is:
In order to obtain sufficient initial strength, the total of orthocresol novolak type epoxy resin and high molecular weight epoxy resin is 100
It is desirable to contain 70 to 10% by weight in terms of% by weight.
If the amount of the high molecular weight epoxy resin is less than the lower limit, the film forming property of the binder resin in the first half of the paper machine drying zone cannot be increased, and the process strength (initial development strength) is undesirably reduced. Alternatively, it is conceivable to take a long time for the curing reaction because the strength development of the binder resin becomes slow, but in a continuous operation for obtaining sufficient strength, the speed becomes low,
Productivity decreases. If the amount of the high molecular weight epoxy resin exceeds the upper limit, the amount of the ortho-cresol novolak type epoxy resin relatively decreases, so that a sufficient crosslink density after curing cannot be obtained, and the strength (solvent resistance) and solder heat resistance And the water absorption is deteriorated, which is not preferable.

The high molecular weight epoxy resin has a molecular weight of 3,000 to
It needs to be 100,000, preferably 5,000 to 20,000. If the molecular weight is less than the lower limit, the film forming property of the binder resin in the first half of the paper machine drying zone becomes insufficient, and the process strength (initial development strength) is undesirably reduced. When the molecular weight exceeds the upper limit, the Tg and the melting point are increased, so that the binder resin is not easily melted in the first half of the paper machine drying zone, so that the film forming property is reduced and the process strength (initial development strength) is reduced. Not preferred. Further, when the molecular weight exceeds the upper limit and is extremely large, it becomes difficult to make the epoxy resin water-soluble, and it is also difficult to form an emulsion.

As the high molecular weight epoxy resin, an epoxy resin having a structure such as glycidyl ether, glycidylamine and glycidyl ester can be used. As specific examples, bisphenol A type, bisphenol F type,
Brized bisphenol A type, phenol novolak type,
Epoxy resins such as cresol novolak type, alcohol type, aromatic amine type, aminophenol type, hydrophthalic acid type, and dimer acid type are exemplified. Among these,
Bisphenol A type is preferred. The reason for this is that bisphenol A type epoxy resin has a film forming property when it has a high molecular weight to some extent, it is easy to chemically modify not only a solvent system but also an aqueous system, and it is relatively inexpensive and easy to use a high molecular weight one. Depending on what you can get.

The curing agent of the present invention contains a compound having active hydrogen as a main component. By using this curing agent for the epoxy resin, the curability is promoted, the solvent resistance of the nonwoven fabric sheet is greatly improved, and the solder heat resistance can be improved. The compound having active hydrogen of the present invention is addition-polymerized with an ortho-cresol novolak type epoxy resin or a high molecular weight epoxy resin having a molecular weight of 3,000 to 100,000 and cured. For example, when a compound having a primary amino group is used as a curing agent, active hydrogen of the primary amino group is subjected to an addition reaction to a glycidyl group to generate a secondary amino group and a hydroxyl group, and this secondary amino group and another glycidyl group are formed. A tertiary amino group and a hydroxyl group (the epoxy resin of the main agent is bonded via N) are formed by the reaction. Even in the case of other compounds having an active hydrogen group, the addition reaction of the curing agent is performed on the β-carbon with little steric hindrance in the form of SN2 to form a crosslinked structure.

Specific examples of the compound include amine compounds such as polyamide and polyamine resin, phenol compounds such as polyphenol resin, mercaptan compounds such as polythiol resin, and organic acid compounds such as carboxylic acid. Among them, dicyandiamide and phenol-based curing agents are preferable in view of compatibility with the matrix resin. In general G-10, G-11, FR-4 and FR-5 grade matrix resins for electrical materials, bisphenol A type epoxy resin (brominated type for flame retardant grade) is often used as the main component. However, since the curing agent used for this is a compound having a large amount of dicyandiamide or phenolic curing agent and having active hydrogen, the interfacial adhesive strength can be improved by unifying the curing system between the binder resin and the matrix resin.

In the present invention, the total epoxy resin and active hydrogen are mixed so that the total number of moles of glycidyl groups in the binder resin and the number of moles of active hydrogen of the compound having active hydrogen are 100: 20 to 100: 100. Are mixed. Even when a plurality of curing agents are used in combination, the above molar ratio is preferably used. If the ratio of the number of moles of active hydrogen of the compound having active hydrogen to the total number of moles of glycidyl groups is less than 100: 20, curing will be insufficient and strength will decrease, and water absorption will also increase. Not preferred. On the other hand, if the molar ratio of active hydrogen exceeds 100: 100, the excess active hydrogen-containing compound remains in the resin and increases the water absorption, which adversely affects solder heat resistance, which is not preferable.

It is effective to use a heat latent catalyst as a curing accelerator. A thermal latent catalyst is a substance that does not have catalytic activity at room temperature but becomes a catalyst when heated. If a catalyst is not used, the time required for the curing agent to crosslink and develop strength in the resin becomes very long, so that the time required for curing in the production line becomes long, resulting in poor operability. Therefore, it is preferable to use a heat latent catalyst. Thermal latent catalysts include benzylsulfonium salts, benzylammonium, pyridium salts, benzylphosphonium salts, hydrazinium salts, carboxylic esters, sulfonic esters,
Amine imide and the like. For example, when 2-ethyl-4methyl-imidazole is used as a catalyst, the reaction speed is increased, and curing is completed in a short time, which is convenient in production. When 2-ethyl-4methyl-imidazole is used, the amount of addition is determined arbitrarily based on the papermaking conditions (production equipment, etc.) and the solvent resistance of the nonwoven fabric sheet to be produced. The range is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the compound.

In the present invention, it is effective to add a suitable amount of a coupling agent, a curing accelerator and the like to a binder resin as required. The coupling agent used is
It is a silane-based, titanate-based, aluminum-based, or zirco-aluminate-based coupling agent, but as a special one, a carboxylic acid-based, phosphoric-acid-based, fatty acid / fats or the like can be used. Among them, particularly in the case of a nonwoven fabric using glass fiber, it is known that a silane coupling agent is very effective, and heat resistance and electric insulation are improved.

As the fibers used in the present invention, chopped strands, cut fibers, pulp, staples and the like selected from organic or inorganic fibers are used. The type of fiber may be one type or a blend of various types. The fiber component may be any of various glass fibers, various synthetic polymer fibers, inorganic fibers, etc., but has an insulating property used as an electrical insulating material, and its melting point is lower than the solder heat resistance temperature.
It needs to be 260 ° C or higher. Specifically, E glass for electrical insulation, NE glass for electrical insulation, ceramic,
Para-aramid, meta-aramid, PEEK (polyetheretherketone), PPO (polyphenylene oxide), PI (polyimide), PAI (polyamideimide), PPS (polyparaphenylene sulfide), P
BO (polyparaphenylene benzobisoxazole),
Fibers such as liquid crystal polyester correspond, but are not limited thereto.

In the present invention, the non-woven fabric for the laminate is made of fibers 80
~ 97% by weight and binder resin to bind fibers 20 ~ 3
% By weight. If the content of the binder resin is less than 3% by weight, the strength of the non-woven fabric is reduced, and in the process of impregnating the epoxy varnish into a prepreg, there is a problem such as paper breakage,
It is not preferable because fluff is generated on the surface of the nonwoven fabric. If the amount of the binder resin exceeds 20% by weight, problems such as an increase in water absorption of the entire nonwoven fabric and loss of the flexibility of the nonwoven fabric occur.

The method of forming the nonwoven fabric in the present invention is not particularly limited, and any of a wet method and a dry method may be used. However, in order to obtain a substrate having a higher density, the wet method is preferably used. Good.

The method of adding the binder resin to the prepared sheet includes a method of spraying and spraying, a method of impregnating the sheet with a binder solution, a method of coating the sheet with a binder solution, and the like. Good. After the addition of the binder resin, the nonwoven fabric of the present invention is obtained by drying and curing with hot air or a drum dryer.

The nonwoven fabric prepared as described above is impregnated into a matrix resin varnish. It is usual to use an epoxy resin as the resin, but a PPE (PPO) resin, a phenol resin, a polyimide resin, or the like can also be used. The varnish concentration is adjusted as appropriate, and the excess that has been impregnated is dropped between rollers or, if the varnish viscosity is low, the entire nonwoven fabric is suspended vertically and dropped by gravity, leaving the required amount in the nonwoven fabric.

The nonwoven fabric impregnated with the varnish is dried and cured at about 130 to 160 ° C., and is set to the B stage to prepare a prepreg. Several prepregs are laminated (in the case of a printed wiring board, copper foil is laminated on the surface), and thermoformed while being pressed at about 150 to 200 ° C. to obtain an insulating board or a printed wiring board.

[0036]

Next, the present invention will be specifically described with reference to the following examples.

Example 1 A glass fiber chopped strand made of E glass (manufactured by NEC Corporation, fiber diameter φ9 μm, fiber length 13 mm) was used for 95 pieces.
Sheets were formed by a wet weight method (with respect to non-woven fabric). On the other hand, ortho-cresol novolak type epoxy resin and bisphenol A type epoxy resin (molecular weight: 20,000, forced emulsification) were mixed in a ratio of 7: 3.
A mixture of the epoxy emulsion, dicyandiamide (aqueous solution), 2-ethyl-4methyl-imidazole and diaminosilane coupling agent in an active ingredient weight ratio of 100: 5:
A binder solution mixed at 1: 1 was prepared (glycidyl group:
(Active hydrogen = 100: 40), and sprayed on the sheet by a spray method so as to have an effective solid content of 5% by weight with respect to the nonwoven fabric, dried at 170 ° C. for 30 minutes and cured to obtain a nonwoven fabric having a basis weight of 80 g / m ² . Table 1 shows the structure, initial development strength, and ultimate strength of this nonwoven fabric. The nonwoven fabric was impregnated with an epoxy resin varnish to remove the excess, and dried and cured at 140 ° C. for 5 minutes to obtain a prepreg. Next, four prepregs were laminated and cured by hot pressing at 180 ° C. for 1 hour to obtain a laminate having a thickness of 0.6 mm. This laminate was evaluated for solder heat resistance. Table 2 shows the results.

Comparative Example 1 A glass fiber chopped strand made of E glass (manufactured by Nippon Electric Glass Co., Ltd., fiber diameter φ9 μm, fiber length 13 mm) was mixed with 95
Sheets were formed by a wet weight method (with respect to non-woven fabric). On the other hand, an orthocresol novolak type epoxy resin emulsion and dicyandiamide (aqueous solution) and 2-ethyl-4-methyl-
A binder solution is prepared by mixing imidazole and diaminosilane coupling agent at an active ingredient weight ratio of 100: 5: 1: 1 (glycidyl group: active hydrogen = 100: 60) so that the non-woven fabric has an effective solid content of 5% by weight. It was spread on this sheet by a spray method, dried at 170 ° C. for 30 minutes and cured to obtain a nonwoven fabric having a basis weight of 80 g / m ² . Table 1 shows the structure, initial development strength, and ultimate strength of this nonwoven fabric. The nonwoven fabric was impregnated with an epoxy resin varnish to remove the excess, and dried and cured at 140 ° C. for 5 minutes to obtain a prepreg. Next, four prepregs were laminated and cured by hot pressing at 180 ° C. for 1 hour to obtain a laminate having a thickness of 0.6 mm. This laminate was evaluated for solder heat resistance. Table 2 shows the results.

Comparative Example 2 A glass fiber chopped strand made of E glass (manufactured by Nippon Electric Glass Co., Ltd., fiber diameter φ9 μm, fiber length 13 mm) was 95
Sheets were formed by a wet weight method (with respect to non-woven fabric). On the other hand, a binder liquid is prepared by mixing a bisphenol A type epoxy resin emulsion, a melamine resin (aqueous solution) and a diaminosilane coupling agent at an active ingredient weight ratio of 100: 10: 1 so that the effective solid content with respect to the nonwoven fabric is 5% by weight. It was spread on this sheet by a spray method, dried at 170 ° C. for 30 minutes and cured to obtain a nonwoven fabric having a basis weight of 80 g / m ² . Table 1 shows the structure, initial development strength, and ultimate strength of this nonwoven fabric. This non-woven fabric is impregnated with epoxy resin varnish to remove excess,
It was dried and heat-cured at 5 ° C. for 5 minutes to obtain a prepreg. Next, four prepregs were laminated and cured by hot pressing at 180 ° C. for 1 hour to obtain a laminate having a thickness of 0.6 mm. This laminate was evaluated for solder heat resistance. Table 2 shows the results.

[0040]

[Measurement method and evaluation method] Functional group ratio: The ratio of the reactive functional group equivalent of the binder resin. Initial strength of nonwoven fabric (kgf / 15mm): Tensile strength measured after air drying of binder solution and treatment at 105 ° C for 10 seconds. The span is 100mm and the pulling speed is 10mm / min. Solvent strength of nonwoven fabric (kgf / 15mm): Tensile strength measured after immersion in acetone for 5 minutes. The span is 100mm,
Tensile speed is 10mm / min. Heat resistance test of laminated board: Blistering that occurs after soldering heat test (260 ° C, 20 seconds immersion) specified in JIS C-6481 by subjecting the laminated board to water absorption treatment by boiling treatment and pressure cooker (121 ° C, 2 atm) treatment. The situation was evaluated. Evaluation criteria n = 3, 3 points for zero defects, 2 points for few defects,
The number of defects is defined as one point, and the occurrence of defects is defined as zero on the entire surface.

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

The nonwoven fabric for a laminate according to the present invention is characterized in that the strength of the nonwoven fabric, the solder heat resistance after the absorption of water in the laminate state, and the water absorption rate can be sufficiently maintained, and sheet breakage in the production line can be significantly reduced. have. this is,
The incorporation of a high molecular weight epoxy resin in the binder resin improved the film forming properties in the initial stages of drying and curing, so that the initial strength development was much faster and higher than in the past. That's why.

Claims (3)

[Claims] 1. A nonwoven fabric for a laminate comprising 80 to 97% by weight of a fiber and 20 to 3% by weight of a binder resin for binding fibers, wherein (1) the binder resin contains a main agent and a curing agent as main components, (2) The main component of the binder resin is ortho-cresol novolak type epoxy resin of 90 to 30% by weight and molecular weight of 3,000 to
Consisting of 100,000 high molecular weight epoxy resin 10-70% by weight,
(3) The curing agent is a compound having active hydrogen, and (4)
The ratio of the total number of moles of glycidyl groups in the binder resin and the total number of moles of active hydrogen in the curing agent is 100: 20 to 100:
Nonwoven fabric for laminates in the range of 100. 2. The method according to claim 1, wherein the curing agent in the binder resin is at least one compound selected from an amine compound, a phenol compound, a mercaptan compound, and an organic acid compound. Nonwoven for laminated board. 3. A printed wiring board or an insulating board made from the nonwoven fabric for a laminate according to claim 1.