JP2012228884A - Prepreg, and laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prepreg that can improve adhesion between prepregs without need of a low-molecular-weight component to be newly added for enhancing the fluidity of the resin and in a wide controllable range of the fluidity and also can improve the solder heat resistance in the case of a kind of resin highly filled with an inorganic filler, to provide a laminate including the prepreg, and to provide a process for producing the laminate.SOLUTION: The prepreg is produced by impregnating a reinforcing material with a resin and has through-holes. The laminate is formed by superposing two or more prepregs comprising the reinforcing material and the resin, on each other, and by disposing a metal foil on one side or both sides of the superposed prepregs to apply heat and pressure. The prepreg has through-holes in the thickness direction of the reinforcing material and the through-holes are filled with the resin.

Description

  The present invention relates to a prepreg and a laminate.

  In recent years, electronic devices have become increasingly smaller, lighter, and multifunctional, and as a result, electronic components such as LSIs and chip components have been highly integrated, and their forms are rapidly becoming more pins and smaller. It has changed. For this reason, the wiring board on which the electronic components are mounted needs to have a higher density and a thinner thickness, and the wiring board is rich in insulation reliability and heat resistance under high density wiring, and is a thin and rigid laminated board and A prepreg for a laminate is desired.

  Furthermore, from the standpoint of environmental preservation in recent years, a laminate containing no halogen and a prepreg for the laminate are required. For example, Patent Document 1 proposes a method of treating aluminum hydroxide with a resin containing an aromatic ring as a method for ensuring flame retardancy without containing halogen or phosphorus. Further, Patent Document 2 proposes a method in which a novolac cyanate and an epoxy resin are highly filled with silica to maintain the rigidity and flexibility of the prepreg.

Japanese Patent Application No. 2004-295821 Japanese Patent Application No. 2004-133900

Such a conventional technique achieves flame retardancy and high rigidity of a laminate without containing halogen or phosphorus by highly filling an inorganic filler in a resin.
On the other hand, when the inorganic filler is highly filled in the resin, the fluidity component is reduced, so that it is difficult to ensure adhesion between the prepregs. For this reason, a phenomenon in which the solder heat resistance is lowered tends to occur in conjunction with the recent increase in the temperature of the lead-free solder bath and the narrowing of the interlayer connection holes.

This decrease in solder heat resistance is more likely to decrease due to moisture absorption of the laminate. In Patent Document 1, the surface of aluminum hydroxide is treated with an aromatic-containing silicone polymer in order to increase the temperature at which the hydrated water of the metal hydrate, which is an inorganic filler, is released and to improve solder heat resistance. This suggests that additional processing steps are required.
In addition, Patent Document 2 proposes adding a low molecular weight component imparting fluidity to the resin in order to increase the fluidity of the resin and improve the flexibility of the prepreg. If a low molecular weight component to be added is added to the resin, it causes a decrease in Tg and a deterioration in flame retardancy, and it is not easy to adjust these characteristics. Further, it is necessary to strictly manage the fluidity of the resin in the prepreg, which is not preferable in terms of production yield.

  The present invention is a resin system in which an inorganic filler is highly filled, and does not require a newly added low molecular weight component that enhances the fluidity of the resin, and between the prepregs in a wide range of fluidity management. It is an object of the present invention to provide a prepreg capable of improving adhesiveness and solder heat resistance, a laminate including the prepreg, and a method for producing the same.

  As a result of intensive studies to achieve the above object, the inventors of the present invention do not need a newly added low molecular weight component that increases the fluidity of the resin in the resin system with a high filler content, and the fluidity It has been found that the adhesiveness between prepregs is improved in a wide range of management width and the hole penetrating through the reinforcing material contained in the laminate and prepreg has a deep relationship, and the present invention is completed. It came to do.

That is, the present invention relates to a prepreg obtained by impregnating a reinforcing material with a resin and having a through-hole.
The present invention is also a laminate obtained by stacking two or more prepregs containing a reinforcing material and a resin, placing metal foil on one side or both sides thereof, and heating and pressing the prepreg, wherein the prepreg comprises the reinforcement. The present invention relates to a laminated board having a hole penetrating in the thickness direction of the material, and the penetrating hole is filled with the resin.

Moreover, this invention relates to the said prepreg and laminated board whose maximum diameter of the hole to penetrate exists in the range of 0.05-10 mm.
Moreover, this invention relates to the said prepreg and laminated board whose number of the through-holes is 1-100 in 1 square cm square of reinforcing materials.

The present invention also relates to the above laminate, wherein the resin impregnated in the prepreg is a resin exhibiting a property of melting in a step of pressing and heating the metal foil and the prepreg.
Further, the present invention is a laminated board including a prepreg having a through-hole and a prepreg containing a reinforcing material and a resin, which does not have a hole penetrating in the thickness direction of the reinforcing material, and does not have a through-hole The prepreg relates to a laminated plate that is disposed so as to be in contact with a prepreg having a through-hole.

  According to the present invention, if the resin has a minimum melt viscosity of 500 to 10,000 Pa · s at a temperature of 80 to 130 ° C., a new additive component that imparts the fluidity of the resin is not required. Thus, the adhesiveness between the prepregs can be improved within a wide range of the property management range, and the prepreg and the laminated plate can be obtained that can obtain the laminated plate that can improve the solder heat resistance.

  The present invention provides a laminate that does not require a new additive component that imparts fluidity, improves adhesion between prepregs in a wide range of fluidity management, and can improve solder heat resistance. For this purpose, the prepreg must have a hole penetrating in the thickness direction. Here, the through-hole may be formed after the prepreg is manufactured, or a through-hole is formed in the reinforcing material before impregnating the resin, and the reinforcing material in which the through-hole is formed is impregnated with the resin. A prepreg may be produced. Furthermore, after manufacturing a prepreg by impregnating a reinforcing material having a through-hole with a resin, the hole may be formed again.

  First, the reinforcing material to be used is not particularly limited as long as it is used when producing a prepreg or a laminate. Examples of the reinforcing material used include inorganic fibers such as glass, alumina, boron, and silica glass, and organic fibers such as aramid, polyetherketone, carbon, and cellulose. As the reinforcing material, reinforcing materials having different thicknesses can be used in order to obtain a predetermined thickness of the laminated plate. The thickness of the reinforcing material is determined by a commercially available product group provided by the manufacturer, but a glass cloth of 0.015 to 0.18 mm is preferable from the viewpoint of handleability. It is not particularly limited to the density, the number of vertical and the number of horizontal of the glass cloth fiber. Further, the shape of the hole penetrating the reinforcing material is not particularly limited.

  Further, the present invention provides a laminate in which a resin eluted from a prepreg flows into a through-hole formed in a reinforcing material, the through-hole is filled with resin, and the upper and lower portions of the through-hole through the filled resin. The resin present in the sphere is integrated, and the anchoring effect improves the adhesion between the prepregs.

  The diameter of the through hole is preferably 0.05 to 10 mm. When the maximum diameter of the through-hole is less than 0.05 mm, the resin does not easily flow into the hole, so that the anchoring effect is hardly exhibited, and the solder heat resistance tends to be reduced. On the other hand, if the maximum diameter of the through-hole exceeds 10 mm, the amount of resin flowing into the hole increases, so that a dent is generated locally and the wiring formability tends to deteriorate. Here, the maximum diameter indicates the major axis when the hole is an ellipse.

  The number of through-holes formed in the prepreg and the reinforcing material varies depending on the maximum diameter of the hole, but the number of through-holes that can ensure solder heat resistance is 1 to 1 square cm square of the reinforcing material. 100. If the number of through-holes is less than one, the number of holes is not sufficient, so that the adhesion between the prepregs cannot be increased and the solder heat resistance tends not to improve. On the other hand, even if the number of through holes exceeds 100, a sufficient effect cannot be expected because holes necessary for improving solder heat resistance are sufficiently secured. The number of holes is preferably 5 to 80, and more preferably 10 to 50.

  The hole formed in the prepreg and the reinforcing material requires a through hole, and the anchoring effect is not sufficient in a non-through hole, and solder heat resistance is reduced. The method for forming these holes is not particularly limited. For example, any method may be used as long as productivity is taken into consideration, such as hammering and punching with a sewing needle, needle piercing with a needle punch, and hammering with a sword. A method of hitting a needle punch needle in which the inner surface of the hole is fuzzy and the shape is complicated is preferable.

The resin impregnated in the reinforcing material can be stored in a prepreg state, and it is necessary to use a resin that exhibits a property of being melted in a pressurizing and heating process for laminating the prepreg. As described above, the improvement in adhesion between the prepregs is achieved by the resin flowing into the holes formed in the prepreg and exhibiting an anchoring effect. Therefore, the resin to be used must exhibit the property of melting in the pressurizing and heating steps for laminating the prepreg, and preferably has a property of being cured by heat after melting.
For example, the minimum melt viscosity at 80 to 130 ° C. is 500 to 10,000 Pa · s, preferably 1000 to 8000 Pa · s, and more preferably 3000 to 5000 Pa · s.

  Here, in the present invention, the melt viscosity was measured by the following method. First, the semi-cured state (B stage) prepreg was loosened even in a plastic bag, and only the resin was collected. Next, this resin was pulverized in a mortar, and about 0.5 g was weighed and formed into a disk shape with a tablet having a diameter of 20 mm using a tablet molding machine. Subsequently, using a rheometer ARES-2K STD-FCO-STD (manufactured by Rheometric), a resin sample molded into a disk shape was heated at a rate of 5 ° C./min, a strain of 5%, a load of 10 g, and a measurement temperature range of 50 to It measured on 200 degreeC conditions.

Examples of the resin exhibiting the property of melting in the heating step described above include epoxy resins, phenol resins, resins modified with epoxy groups and phenol hydroxyl groups, and mixtures thereof.
In addition, although it does not show the property of melting in the heating step, a thermoplastic resin such as polyimide (PI), polyamideimide (PAI), polyethersulfone (PES), polyetherimide (PEI) is necessary for the above-described resin. You may mix according to it.

Furthermore, the resin includes silica, fused silica, talc, alumina, aluminum hydroxide, barium sulfate, calcium hydroxide, erosyl, calcium carbonate and other inorganic fillers, NBR particles and acrylic rubber particles, and a core shell having these shell structures You may mix organic fillers, such as particle | grains. As the filler, aluminum hydroxide is preferable.
Moreover, a filler can be 20 Vol% or more.

  The resin must be dissolved in a solvent such as methyl ethyl ketone, methyl ethyl isobutyl ketone, N-methyl pyrrolidone, dimethyl formamide, dimethyl sulfoxide, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate. These resins can be appropriately selected depending on the dissolved state and the method of impregnating the resin with the reinforcing material. For example, an epoxy resin can be selected when the solvent is methyl ethyl ketone, and a phenol resin can be selected when the solvent is propylene glycol monomethyl ether.

  The method for impregnating the reinforcing material with the resin is not particularly limited, and a known method can be used. For example, the cut bar coating can be performed by squeezing the impregnated resin with a roll, the kiss coating can be performed while the resin is rotated while being rotated by the roll, the lip coating by which the resin is adhered to the reinforcing material by pressure, and the spray coating.

  The prepreg is laminated with a metal foil, formed into a laminate by pressurization, and heating. However, the prepreg must be stored in a prepreg state until it is processed into a laminate. For this reason, the resin solvent impregnated in the reinforcing material is volatilized so that it can be handled in a semi-cured state (B-stage state).

  The conditions for volatilizing the solvent are those at 100 to 200 ° C. for 1 to 20 minutes. Moreover, although it is not necessary to volatilize and remove a solvent completely, it is preferable that the amount of residual solvents is 0 to 5 weight% for handling property.

The produced prepreg is stacked together with the metal foil and cured by pressing and heating. After the preparation of the prepreg, a through hole may be formed before the pressurization and heating step, or a through hole may be further formed in the prepreg impregnated with a resin in a reinforcing material in which the through hole is formed in advance. However, the above-mentioned hole shape and density conditions must be satisfied. This is because, in order to exert the anchoring effect, the hole may be formed at any time as long as the conditions of the shape and density of the hole are satisfied.
In addition, all or some of the prepregs having through holes may be used. This is because a prepreg having a through hole can be bonded to the prepreg having no through hole by an anchoring effect.

  Although it does not specifically limit as metal foil, Copper foil is preferable. The copper foil is not particularly limited. For example, general electrolytic foil, low profile foil, rolled foil, and the like can be suitably used. Moreover, as for the thickness of metal foil, 12-18 micrometers is preferable. As for the lamination condition, it is sufficient if an appropriate condition is selected according to the resin to be used. For example, when using copper foil, the temperature is raised from 35 to 200 ° C. for 50 minutes at a rate of temperature rise of 3 ° C./min, held at 185 ° C. and a pressure of 2.0 to 3.0 MPa for 60 to 90 minutes, and then to room temperature. Cool in 30 minutes to make a laminate.

  It is also possible to use a prepreg having a through-hole and a prepreg not having a through-hole. In this case, two or more prepregs having no through-hole do not overlap so that a prepreg having a through-hole is provided. Need to be inserted. The reason for this is that the resin flows into the holes of the prepreg having the through holes so that the prepreg having no through holes can be bonded by the anchoring effect.

  In the produced metal-clad laminate, electrical connection holes are formed using a known technique such as a drill or a laser. This electrical connection hole may be after the metal is removed by etching. Next, the metal foil is removed by etching.

  This etching is not particularly limited as long as it chemically dissolves the metal. When the metal is copper, copper is dissolved and removed using a known technique such as ferric chloride / hydrochloric acid aqueous solution, ammonium persulfate aqueous solution, sulfuric acid / hydrogen peroxide aqueous solution. And it transfers to a desmear process and an electroless-plating process.

  The desmear treatment essentially includes a contact step with a swelling aqueous solution and a contact step with a permanganate strong alkaline aqueous solution. The contact step of the swelling aqueous solution is a step of treating the laminate from which the metal has been removed with a mixed aqueous solution of alcohol and alkali.

  This mixed aqueous solution of alcohol and alkali is an aqueous solution in which diethylene glycol monobutyl ether and sodium hydroxide are mixed, and is also called a sweller liquid. The ratio is 100-400 ml / l for diethylene glycol monobutyl ether and 1-10 g / l for sodium hydroxide.

  Examples of commercially available sweller liquids include Securigant P (trade name, manufactured by Atotech Japan Co., Ltd.), Circoposit MLB Conditioner 211 (trade name, manufactured by Rohm & Haas Japan Co., Ltd.), and the like.

As a method for contacting the laminate with the swelling aqueous solution, a spray method, a dip method, a jet method, or the like can be used. In the case of a dip method, conditions are implemented at 60-90 degreeC for 2 to 20 minutes.
Then, after passing through a water washing process, it is attached | subjected to the contact process of the permanganic-acid type strong alkali aqueous solution.

  This strong permanganate aqueous solution is obtained by dissolving an oxidizing agent such as sodium permanganate and potassium permanganate and sodium hydroxide as an alkali source in water, and is also called a manganese etching solution. The ratio is 30 to 80 g / l for sodium permanganate or potassium permanganate and 20 to 60 g / l for sodium hydroxide.

  Examples of commercially available manganese etching solutions include Concentrate Compact CP (trade name, manufactured by Atotech Japan Co., Ltd.), Circoposit MLB Promoter 213 (trade name, manufactured by Rohm & Haas Japan Co., Ltd.), and the like.

  As a method for contacting the laminate with the permanganic acid strong alkaline aqueous solution, a spray method, a dip method, a jet method, or the like can be used. In the case of a dip method, conditions are carried out at 60 to 90 ° C. for 4 to 30 minutes.

  Subsequently, using an aqueous hydroxylamine sulfate solution and an aqueous sulfuric acid / hydrogen peroxide solution, the mixture is treated at 40 to 45 ° C. for 3 to 10 minutes to neutralize the alkali. Such aqueous solutions include, for example, Reduction Solution Securigant P-500 (trade name, manufactured by Atotech Japan Co., Ltd.), MLB New Trizer 216 (trade name, manufactured by Rohm & Haas Japan Co., Ltd.) and the like as commercial products.

  Further, it is subjected to a pretreatment process of electroless plating. These steps can be performed by a known method. For example, conditioner liquid, CLC-501 (trade name, manufactured by Hitachi Chemical Co., Ltd.) 100 ml / l aqueous solution, treated at 60 ° C. for 5 minutes, then washed with water, pre-dip liquid, PD-201 (trade name) aqueous solution Treated at room temperature for 3 minutes, treated in an aqueous solution containing a metal palladium solution, HS-202B (trade name) at room temperature for 10 minutes, then washed with water, activated treatment solution, ADP-501 (trade name) aqueous solution Process for 5 minutes at room temperature.

  By these pretreatment steps, an electroless plating layer is formed on the laminate. The electroless plating layer can be produced by bringing a substrate that has been pretreated with the electroless plating into contact with an electroless plating solution. Examples of the contact method include, but are not limited to, a horizontal conveyance type and a dip type.

  The thickness of the electroless plating layer is preferably in the range of 0.2 to 2 μm. When the thickness of the electroless plating layer is less than 0.2 μm, the solder heat resistance tends to decrease. On the other hand, if it exceeds 2 μm, blistering tends to occur between the deposited electroless plating layer and the laminate.

  Examples of the electroless plating solution include Rochelle salt and EDTA base electroless copper plating solutions, but are not particularly limited. These are, for example, Cust-201, Cust-1160, Cust-4600 (trade name, manufactured by Hitachi Chemical Co., Ltd.), Sulcup PEA (trade name, manufactured by Uemura Industrial Co., Ltd.), OPC Copper H (trade name). , Manufactured by Okuno Pharmaceutical Co., Ltd.).

  After washing with water, drying, and plating up to the required thickness using electrolytically plated copper, in the case of the semi-additive method, the plating resist is removed, and in the case of a subtractive method such as the tenting method, copper is added. A liquid such as ammonium sulfate is used for dissolution and removal (etching) to produce a wiring conductor to obtain a wiring board.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a table | surface, these description is an illustration and does not limit the scope of the present invention.

Example 1
(1) Preparation of resin for glass cloth impregnation A resin for glass cloth impregnation having the following composition and a composition of aluminum hydroxide of 32 vol% was prepared. The resin had a viscosity of 3900 Pa · s at 100 ° C.
・ Novolak phenol type epoxy resin, N-770 (trade name, manufactured by Dainippon Ink Co., Ltd.) 30 g
・ Novolak phenol resin, HP-850 (trade name, manufactured by Hitachi Chemical Co., Ltd.) 16g
・ Dicyandiamide (trade name, manufactured by Nippon Carbide Corporation) 0.04 g
Aluminum hydroxide (average particle size 1.0 μm), Heidilite H-42M (trade name, manufactured by Showa Denko) 40 g
・ Antioxidant, Yoshinox BB (trade name, manufactured by API Corporation) 6g
・ Solvent, methyl ethyl ketone (reagent) 80g

(2) Preparation of prepreg with a through-hole formed IPC name # 2116 Glass cloth (thickness: 96 μm) with needle punch and applique puncher thick needle type (needle tip diameter 0.65 mm, manufactured by Clover Co., Ltd.) Punched and formed a through hole. The maximum diameter of the through-hole was 1.0 mm, and the number of through-holes was 53 in 1 cm 2.

  Next, the resin described in Example 1 (1) was impregnated into a glass cloth in which a through-hole was formed using cut bar coating. In order to adjust the gel time, it was dried at 150 ° C. for 5 minutes. The gap and pulling speed were adjusted so that the amount of resin impregnated into the glass cloth was 50 ± 5 wt% with respect to the prepreg after drying. The gel time at 170 ° C. of the resin collected from the prepreg was 155 seconds.

(3) Production of copper-clad laminate Four prepregs produced in Example 1 (2) were overlaid, and 18 μm thick copper foil, YGP-18 (trade name) was overlaid on both sides of the prepreg, and 90 ° C. at 175 ° C. A double-sided copper-clad laminate was produced under a pressing condition of 2.5 MPa for 2.5 minutes.

(4) Characteristic evaluation of copper-clad laminate (a) Normal solder heat resistance The copper-clad laminate produced in Example 1 (3) was cut into 25 mm squares and dried at 105 ° C for 60 minutes. Subsequently, it was adjusted to 288 ° C. ± 1 ° C., and the time until it floated in the solder bath and blistering was examined.

(B) Hygroscopic solder heat resistance The copper-clad laminate produced in Example 1 (3) was immersed in an aqueous solution of ammonium persulfate 100 g / L to dissolve and remove copper. Thereafter, it was cut into 40 mm square and dried at 105 ° C. for 60 minutes. Next, the moisture absorption treatment was performed by changing the time with a saturated pressure cooker apparatus at 121 ° C. and 100% RH. The treated laminate was adjusted to 288 ° C. ± 1 ° C. and immersed in a solder bath for 20 seconds, and the moisture absorption treatment time until blistering was examined.

(C) Copper foil peeling strength The test method was based on JIS-C-6481. The copper-clad laminate produced in Example 1 (3) was cut into 25 × 100 mm strips. And 10 mm width mylar tape was affixed on the copper foil part. Subsequently, it was immersed in an aqueous solution of ammonium persulfate 100 g / L to dissolve and remove the portion of copper where the Mylar tape was not attached.

  Next, the mylar tape was peeled off to form a line having a copper width of 10 × 100 mm. After drying the test piece at 105 ° C. for 30 minutes, the copper foil was peeled off at a pulling rate of 50 mm / min, and the peel strength of the copper foil was determined.

(D) Flame retardancy The test method followed the UL-94 method. The copper-clad laminate produced in Example 1 (3) was immersed in an aqueous solution of 100 g / L ammonium persulfate to dissolve and remove copper entirely. A flame retardant test piece was prepared using this sample.

Example 2
The same procedure as in Example 1 was performed except that the method of forming the hole penetrating the glass cloth was changed. In Example 2, a drill blade having a drill diameter of 0.5 mm (manufactured by Mitsubishi Materials Corporation) was used, and the drill blade was hit with a hammer to form a hole penetrating the glass cloth. The maximum diameter of the through hole was 1.0 mm. The number of through holes was 5/1 square cm square.

Example 3
The same operation as in Example 1 was performed except that a part of the glass cloth in which a through-hole was formed was used. A prepreg obtained by impregnating a resin into a glass cloth in which no through-hole was formed was produced. This prepreg and the prepreg impregnated with the resin in the glass cloth in which the through hole is formed are alternately overlapped, and the prepreg impregnated with the resin in the glass cloth in which the through hole is formed is arranged on the copper foil side. . The total number of prepregs used was five.

Example 4
It carried out similarly to Example 1 except having changed the thickness of the glass cloth to be used, and the conditions of the hole to penetrate. The glass cloth was changed to IPC name # 3313 glass cloth (thickness 80 μm).
Moreover, the maximum diameter of the hole when the hole penetrating the glass cloth with the same needle punch as in Example 1 was 5 mm. Further, the number of through holes was 7 in 1 cm 2.

Example 5
The same procedure as in Example 1 was performed except that the resin used was changed to the following composition in which aluminum hydroxide was 21 vol%. The viscosity of the resin was 1300 Pa · s at 100 ° C.
・ Novolak phenol type epoxy resin, N-770 (trade name, manufactured by Dainippon Ink Co., Ltd.) 30 g
・ Novolak phenol resin, HP-850 (trade name, manufactured by Hitachi Chemical Co., Ltd.) 16g
・ Dicyandiamide (trade name, manufactured by Nippon Carbide Corporation) 0.04g
・ Aluminum hydroxide (average particle size 1.0 μm), Heidilite H-42M (trade name, manufactured by Showa Denko KK) 22 g
・ Antioxidant, Yoshinox BB (trade name, manufactured by API Corporation) 6g
Solvent, methyl ethyl ketone (reagent) 80g

Example 6
The hole through which the reinforcing material passes was changed to a method of forming after the preparation of the prepreg. The through holes were formed in the same manner as in Example 1, and four prepregs in which the through holes were formed were overlapped to produce a double-sided copper-clad laminate under the same conditions as in Example 1.

Comparative Example 1
Only a prepreg impregnated with a resin in a glass cloth in which no through-hole was formed was used. Others were performed in the same manner as in Example 1.

Comparative Example 2
Except that a prepreg impregnated with resin in a glass cloth with a through-hole formed was placed on the copper foil side, and a laminated sheet was produced by stacking two prepregs impregnated with resin into a glass cloth without a through-hole formed. The same procedure as in Example 1 was performed.

Comparative Example 3
A prepreg in which the resin of Example 5 was impregnated into a glass cloth in which no through-hole was formed was produced. A laminate was produced using only this prepreg. Others were performed in the same manner as in Example 1.

  The laminates prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were evaluated for normal solder heat resistance, hygroscopic solder heat resistance, copper foil peel strength, and flame retardancy. The results are shown in Tables 1 and 2.

When Examples 1 to 4 and 6 are compared with Comparative Examples 1 and 2, the effect of the present invention becomes clear in a resin system having a high content of aluminum hydroxide that does not contain halogen and can ensure flame retardancy. That is, when a glass cloth is impregnated with a resin having a high aluminum hydroxide content, normal solder heat resistance and hygroscopic solder heat resistance cannot be secured unless through holes are formed in the glass cloth as in the present invention. .
On the other hand, when Example 5 and Comparative Example 3 are compared, in the resin system having a low content of aluminum hydroxide that does not contain halogen and cannot ensure flame retardancy, characteristics other than flame retardancy can be secured, but penetration When a laminated board was produced using the prepreg produced using the glass cloth which formed the hole, the flame retardance improved. This is presumed that the oxygen entry path was blocked by the improved adhesion between the layers.

Claims (20)

A prepreg including a reinforcing material and a resin,
A prepreg having a hole penetrating in the thickness direction of the reinforcing material.   The prepreg according to claim 1, wherein the maximum diameter of the through-hole is 0.05 to 10 mm.   The prepreg according to claim 1, wherein the number of through holes is 1 to 100 per square centimeter of reinforcing material.   The prepreg according to claim 1, wherein the reinforcing material is glass cloth, polyamide or cellulose.   The prepreg according to claim 1, wherein the resin has a minimum melt viscosity of 500 to 10,000 Pa · s at a temperature of 80 to 130 ° C.   The resin according to claim 1, which is an epoxy resin, a phenol resin, a resin modified with an epoxy group or a phenol hydroxyl group, and a mixture thereof, which may contain polyimide, polyamideimide, polyethersulfone or polyetherimide. Prepreg.   The prepreg according to claim 1, wherein the resin contains a filler.   The prepreg according to claim 1, wherein the filler is aluminum hydroxide. A method for producing the prepreg according to claim 1,
a) impregnating a resin with a reinforcing material;
b) forming a hole in the reinforcing material;
Including methods. A laminate obtained by stacking two or more prepregs containing a reinforcing material and a resin, placing a metal foil on one side or both sides thereof, and heating and pressing,
A laminate in which the prepreg has a hole penetrating in the thickness direction of the reinforcing material, and the penetrating hole is filled with the resin. The laminate according to claim 10, further comprising one or more prepregs having no holes penetrating in the thickness direction of the reinforcing material,
The prepreg that does not have a through-hole is a laminated plate that is disposed so as to be in contact with the prepreg that has a through-hole.   The laminated board of Claim 10 or 11 whose maximum diameter of the hole which penetrates is 0.05-10 mm.   The laminated board of Claim 10 or 11 whose number of the through-holes is 1-100 in 1 square cm square of reinforcing materials.   The laminate according to claim 10 or 11, wherein the reinforcing material is glass cloth, polyamide or cellulose.   The laminate according to claim 10 or 11, wherein the resin has a minimum melt viscosity of 500 to 10,000 Pa · s at a temperature of 80 to 130 ° C.   The resin is an epoxy resin, a phenol resin, a resin modified with an epoxy group or a phenol hydroxyl group, and a mixture thereof, which may contain polyimide, polyamide imide, polyether sulfone or polyether imide. The laminated board of description.   The laminated board of Claim 10 or 11 in which resin contains a filler.   The laminate according to claim 10 or 11, wherein the filler is aluminum hydroxide.   The laminate according to claim 10 or 11, wherein the metal foil is a copper foil. A method for producing the laminate according to claim 10, comprising:
A step of stacking a plurality of prepregs according to claim 1 by a required thickness;
Arranging the metal foil on one or both sides thereof;
Heating and pressurizing steps;
Including methods.