JP2002225056A - Method for producing composite laminated plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composite laminated plate good in warpage in a processing process while a solvent consumption and heat energy are reduced as compared with a method for producing a conventional laminated plate. SOLUTION: A method for producing the composite laminated plate includes a process in which an epoxy resin varnish (a) is applied from one side of a glass fabric; a process in which an intermediate layer epoxy resin varnish (b) is applied on the surface coated with the varnish (a) of the fabric; a process in which a glass nonwoven fabric is laid on the surface coated with the varnish (b) to overlap each other, and a prepreg is manufactured by heating and drying; and a process in which the two prepregs are laid to overlap each other with the nonwoven fabrics arranged inside, and subjected to heating pressure molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a composite laminate suitable for use in a printed circuit board particularly used in electric equipment, electronic equipment, communication equipment and the like.

[0002]

2. Description of the Related Art Composite printed circuit boards made of glass non-woven fabric as an intermediate layer base material, glass woven fabric as a surface layer base material, and impregnated with epoxy resin varnish and heated and pressed as a printed circuit board have conventionally been used as intermediate layers of glass non-woven fabrics. A prepreg which is impregnated with a layer resin varnish and dried, and a prepreg which is impregnated with a glass woven fabric and impregnated with an epoxy resin varnish are separately produced, and are laminated and superimposed at the time of heat and pressure molding.

Recently, in the production of composite laminates, in order to reduce the burden on the environment, a glass woven fabric is impregnated with a resin varnish in order to reduce the amount of solvent used and thermal energy. After applying the paste-like intermediate layer resin with less content, the glass non-woven fabric is overlapped and dried again by heating to produce a prepreg, and the two prepregs are laminated with the glass non-woven fabric inside and heated and pressed to form a composite. The manufacture of laminates is being considered. However, in such a production method, there is a problem that the adhesion between the resin impregnated glass woven fabric of the surface layer and the intermediate layer resin becomes insufficient because the viscosity of the intermediate layer resin varnish is high at the time of preparing the prepreg. . In order to solve this problem, a method was considered in which the intermediate layer resin was applied and then heated and the glass nonwoven fabric was superimposed.However, due to the evaporation of the solvent, the viscosity of the intermediate layer resin surface became higher and the glass nonwoven fabric became an intermediate layer. It does not disperse uniformly in the resin, and as a result, there arises a problem that the warpage in the processing step of the obtained laminated board deteriorates.

As a method of reducing the uneven distribution of the glass nonwoven fabric, a method of reducing the amount of glass fibers has been studied. However, although the uneven distribution in the interlayer resin can be solved by reducing the amount of glass fibers, there is a problem that the warpage in the processing step of the laminated plate after the heat molding is deteriorated.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been completed as a result of various studies to solve the problem of adhesion between layers and the uneven distribution of glass nonwoven fabric in a method of manufacturing a composite laminate. It is an object of the present invention to obtain a composite laminate having excellent characteristics free from problems of adhesion between layers and warping while maintaining a reduction in the amount of solvent used and a reduction in heat energy.

[0006]

According to the present invention, there is provided (1) a step of applying an epoxy resin varnish (a) from one side of a glass woven fabric, and an intermediate layer on the surface of the glass woven fabric to which the epoxy resin varnish (a) is applied. A step of applying an epoxy resin varnish (b),
A step of laminating a glass nonwoven fabric on the surface coated with the intermediate layer epoxy resin varnish, heating and drying to prepare a prepreg, and then laminating and heat-pressing the two prepregs with the glass nonwoven fabric inside. A method of manufacturing a composite laminate, (2) a step of applying an epoxy resin varnish (a) from one side of a glass woven fabric, and an intermediate layer epoxy resin varnish on a surface of the glass woven fabric to which an epoxy resin varnish (a) is applied. (B) application step, after laminating a glass non-woven fabric on the surface of the intermediate layer epoxy resin varnish application, impregnating the epoxy resin varnish (c) from the glass woven cloth side, and heating and drying to prepare a prepreg Then, the two prepregs are laminated with the glass non-woven fabric on the inside, and heated and pressed to form a composite. (3) The method for producing a laminate, (3) the intermediate layer epoxy resin varnish (b) contains 80 to 150 parts by weight of a filler based on 100 parts by weight of an epoxy resin (including a curing agent) or (2). )).

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One of the features of the present invention is that an epoxy resin varnish (a) is applied from one side of a glass woven fabric. By applying the varnish from one side, the air inside the woven fabric can be easily replaced with the varnish, a prepreg with few voids can be obtained, and the resin on the side where the varnish is applied can be increased, and Adhesion with the layer can be improved. The glass woven fabric used in the present invention is not particularly limited, and an ordinary epoxy resin glass laminate is used.

[0008] The epoxy resin used in the epoxy resin varnish (a) used in the present invention is not particularly limited as long as it is an epoxy resin used for an ordinary laminated board. Bisphenol A type epoxy resin, novolak type epoxy resin Epoxy resin and the like. Epoxy resin varnish (a)
The solid content is usually 35 to 85% by weight, and preferably 55 to 75% by weight in consideration of solvent reduction and impregnation. In order to impart thixotropy and sufficiently retain the resin on the glass woven fabric, it is preferable to mix 1 to 10 parts by weight of a fine particle inorganic filler having an average particle diameter of 1 μm or less based on 100 parts by weight of the epoxy resin varnish. When the amount is less than 1 part by weight, the effect of blending the fine particle filler is small, and when the amount is more than 10 parts by weight, the impregnating property to the glass woven fabric is reduced. Preferably, the amount is 1 to 5 parts by weight from the balance between the retentivity to the glass woven fabric and the impregnation.
Examples of the fine particle filler include fine particle silica and aluminum hydroxide.

The epoxy resin varnish applied here (a)
Is preferably 50 to 150 parts by weight based on 100 parts by weight of the glass woven fabric in the solid content including the filler. If the amount is less than 50 parts by weight, the adhesion to the interlayer resin or the glass non-woven fabric is reduced, and various characteristics are reduced. If the amount is more than 150 parts by weight, the resin content will be excessive, and the thermal properties of the laminate will deteriorate. In the present invention, after the epoxy resin varnish (a) is applied to one side of the glass woven fabric, it is preferable to heat and dry at 120 to 180 ° C. for 1 to 10 minutes in order to effectively evaporate the solvent.

Another feature of the present invention is that an intermediate layer epoxy resin varnish (b) for impregnating a glass nonwoven fabric is applied to an epoxy resin varnish (a) application surface of a glass woven fabric. Such a method is a preferable method for obtaining good adhesion between the intermediate layer resin and the epoxy resin impregnated glass woven fabric of the surface layer, and is further compared with a method in which a glass nonwoven fabric is immersed in a varnish for impregnation. Thus, the process is simple, and the cutting and elongation of the glass nonwoven fabric can be prevented. Therefore, the glass nonwoven fabric can be uniformly dispersed in the prepreg. In order to effectively carry out this step and to reduce the amount of the solvent used for the varnish, it is preferable that the intermediate layer epoxy resin varnish (b) is a paste having a high concentration and a high viscosity.

The epoxy resin used for the intermediate layer epoxy resin varnish (b) used in the present invention is not particularly limited as long as it is an epoxy resin used for an ordinary laminated board. Bisphenol A type epoxy resin, novolak Epoxy resin.

In the present invention, the intermediate layer epoxy resin varnish (b) contains an inorganic filler in an amount of 80 to 150 parts by weight with respect to 100 parts by weight of the epoxy resin in order to reduce the coefficient of thermal expansion and improve the dimensional stability. Of the components are preferred. If the amount is less than 80 parts by weight, the dimensional shrinkage and the like in the processing step tend to be insufficiently improved. Examples of the inorganic filler include aluminum hydroxide, calcium carbonate, clay, talc, and silica, and are not particularly limited. The solid content of the intermediate layer epoxy resin varnish (b) is usually 65 to 95% by weight (the inorganic filler is also calculated as a solid content), and preferably 80 to 95% by weight. The coating amount of the intermediate layer epoxy resin varnish (b) is preferably 500 to 1500 parts by weight based on 100 parts by weight of the glass nonwoven fabric. If the amount is less than 500 parts by weight, the properties at the time of heating and the adhesion between the prepregs tend to decrease.

In the present invention, the intermediate layer epoxy resin varnish (b) is preferably in the form of a paste having a high viscosity as described above. The viscosity ranges from 1 to 10 at the time of coating impregnation.
A poise range is particularly preferred. If it is less than 1 poise, it is difficult to apply the varnish to a predetermined thickness, and if it exceeds 10 poise, it becomes difficult to apply the varnish, and it is difficult to impregnate the varnish into the glass nonwoven fabric in a later step. Therefore, the amount of the solvent used is reduced, and the energy required for subsequent heating and drying can be reduced.

A third feature of the present invention is that, in order to quickly and satisfactorily impregnate the glass nonwoven fabric with the epoxy resin varnish (b), following the application of the epoxy resin varnish (b),
This is to prepare a prepreg by laminating a glass nonwoven fabric on the applied surface and drying by heating. The glass nonwoven fabric used in the present invention is not particularly limited, and those used for ordinary composite laminates are preferably used. Glass nonwovens usually have a weight per unit area of 40-
Those having 150 g / m ² are preferably used. afterwards,
The prepreg is obtained by heating and drying. The heating and drying conditions are
120 to 180 ° C for 1 to 10 minutes is preferred.

In the present invention, preferably, after the above-mentioned glass nonwoven fabric is overlaid, an epoxy resin varnish (c) is impregnated from the surface of the glass woven fabric and dried by heating to prepare a prepreg. By adding the step of impregnating the epoxy resin varnish (c), the resin is sufficiently present in the surface layer of the composite laminate, and therefore, the adhesion to the copper foil and the heat resistance are improved. The epoxy resin used for the epoxy resin varnish (c) used in the present invention is not particularly limited, and examples thereof include a bisphenol A type epoxy resin and a novolak type epoxy resin. As the epoxy resin varnish (c), the same or similar epoxy resin varnish (a) can be used. The amount of the epoxy resin varnish (c) is 20 per 100 parts by weight of the glass woven fabric.
-100 parts by weight are preferred. When the amount is less than 20 parts by weight, the above effect is small, and when the amount is more than 100 parts by weight, the amount of the resin is too large, so that the moldability and the dimensional stability are reduced.

In the present invention, a composite laminate is obtained by laminating two glass nonwoven fabrics on the inner side of the obtained prepreg and subjecting them to heat and pressure molding. The forming is the same as the forming of a normal composite laminate. In the present invention, since the glass nonwoven fabric can be uniformly dispersed in the intermediate layer resin of the prepreg, the obtained composite laminate has good warpage in a process of processing into a circuit board.

FIG. 1 shows an example (schematic) of a process for obtaining a prepreg in the present invention. A predetermined amount of epoxy resin varnish (a) 2 is applied by a coater 3 on the upper surface of the glass woven fabric 1 unwound from the unwinding device, and the drying device 4
The intermediate layer epoxy resin varnish (b) is applied thereon by a coater 6 to a predetermined thickness. Subsequently, the glass nonwoven fabric 7 is overlaid on the upper surface without heating and drying. As coaters 3 and 6,
There are a comma roll coater, a knife coater, a die coater, a reverse coater and the like. Next, an epoxy resin varnish (c) 8 is applied from the back surface. This coating is usually performed by a roll coater 9. Thereafter, by heating and drying through a drying device 10, an epoxy resin varnish impregnated prepreg 12 in which a glass nonwoven fabric is laminated on a glass woven fabric is obtained. After that, the prepreg is
To a predetermined length. Alternatively, it is also possible to perform continuous molding without cutting.

[0018]

The present invention will be specifically described below with reference to examples and comparative examples. Glass woven fabric (180g / m
² ) Epoxy resin varnishes (a) and (c) applied to
Epicron 85 as a bisphenol A type epoxy resin
0 (epoxy equivalent 190, manufactured by Dainippon Ink Co., Ltd.), GX153 as a brominated bisphenol A type epoxy resin
(Epoxy equivalent: 400, manufactured by Dainippon Ink Co., Ltd.), tetrabromobisphenol A, PR as novolak resin
-51470 (manufactured by Sumitomo Durez Co., Ltd.), 2-ethyl-4-methylimidazole is used as a curing accelerator, and fine-particle silica is used as an inorganic filler (Shionogi Pharmaceutical Co., Ltd.)
Manufactured by Carplex # 67, average particle diameter 6 μm).
It was blended in the ratio shown in Table 1. Acetone was used as a solvent to obtain a solid content of 70% by weight.

The intermediate layer epoxy resin varnish (b) impregnated in the glass non-woven fabric (100 g / m ² ) is a bisphenol A type epoxy resin such as Epicron 850 (epoxy equivalent 190, manufactured by Dainippon Ink Co., Ltd.), GX153 (epoxy equivalent: 400, manufactured by Dainippon Ink and Chemicals, Inc.) as a brominated bisphenol A type epoxy resin, Crezo-
Epicoat 180 as Lunovolak type epoxy resin
S75 (epoxy equivalent 210, manufactured by Yuka Shell Epoxy Co., Ltd.), PR-51470 as a novolak resin
(Manufactured by Sumitomo Durez Co., Ltd.), 2-ethyl-4-methylimidazole was used as a curing accelerator, and aluminum hydroxide was used as an inorganic filler (manufactured by Sumitomo Chemical Co., Ltd., CL-3).
10) and blended at the ratios shown in Table 1. Acetone was used as a solvent to obtain a solid content of 80% by weight.

In the first embodiment, 100 parts by weight of the epoxy resin varnish (a) is applied to 100 parts by weight of the glass woven cloth on a glass woven cloth, and further, an intermediate layer epoxy resin varnish (b) is applied thereon. 500 parts by weight were applied to 100 parts by weight of the glass woven fabric, and 10 parts by weight of the glass nonwoven fabric was overlaid on the intermediate layer epoxy resin varnish (b) and dried. Then, 50 parts by weight of an epoxy resin varnish (c) was applied to 100 parts by weight of the glass woven fabric from the side of the glass woven fabric, and dried by heating to obtain a prepreg. The two prepregs were laminated with the glass nonwoven fabric side inside, and copper foil was further laminated on both surfaces, and heated and pressed to obtain a composite laminate. In Example 2, 130 parts by weight of the epoxy resin varnish (a) was applied to 100 parts by weight of the glass woven cloth on a glass woven cloth. 500 parts by weight was applied to 100 parts by weight, and 10 parts by weight of a glass nonwoven fabric was overlaid on the intermediate layer epoxy resin varnish (b) from above, and heated and dried to obtain a prepreg. The two prepregs were laminated with the glass nonwoven fabric side inside, and copper foil was further laminated on both surfaces, and heated and pressed to obtain a composite laminate.

In Comparative Example 1, the epoxy resin varnish (a) was impregnated with a glass woven fabric by impregnation, heated and dried, and then an intermediate layer epoxy resin varnish (b) was applied thereon, and the intermediate layer epoxy resin varnish was applied thereon. A glass nonwoven fabric of 10 parts by weight was overlaid on the epoxy resin varnish (b). Next, an epoxy resin varnish (c) was applied from the side of the glass woven fabric, and dried by heating to obtain a prepreg. The two prepregs were laminated with the glass nonwoven fabric side inside, and copper foil was further laminated on both surfaces, and heated and pressed to obtain a composite laminate.
In Comparative Example 2, a glass woven fabric was immersed in the epoxy resin varnish (a) for impregnation, heated and dried, and then an intermediate layer epoxy resin varnish (b) was applied thereon.
For 3 minutes, and 10 parts by weight of a glass nonwoven fabric was overlaid on the intermediate epoxy resin varnish (b) from above. Next, an epoxy resin varnish (c) was applied from the side of the glass woven fabric, and dried by heating to obtain a prepreg. The two prepregs were laminated with the glass nonwoven fabric side inside, and copper foil was further laminated on both surfaces, and heated and pressed to obtain a composite laminate. In the examples and comparative examples, the coating amounts of the resin are all in terms of solid content, and unless otherwise specified, the amounts of the examples and comparative examples are the same. Also,
Heat drying is performed under the same conditions in the same step.

[0022]

[Table 1]

The properties of the prepreg and the formed composite laminate were evaluated, and the properties shown in Table 2 were obtained.

[Table 2]

(Evaluation method) Warping in the processing step: The laminate is cut into 500 × 400 mm and all copper foil is removed. The laminate is placed on a horizontal net rack and heated in a 150 ° C. atmosphere for 30 minutes. It was placed flat on a flat surface plate, and the maximum amount floating from the surface plate was measured to obtain a warpage value. The warpage is measured after removing the copper foil and after heating. 2. Interlayer adhesion: 100 × 100 mm test piece 250
After the treatment in an atmosphere at a temperature of 30 ° C. for 30 minutes, the occurrence of interlayer swelling or peeling between the surface layer and the intermediate layer was visually observed. 3. Solder heat resistance: After performing a moisture absorption treatment for 2 hours by boiling according to JIS C6481, 30
After the immersion for 0 seconds, the presence or absence of abnormal appearance was examined. A sample without swelling was rated as ○, and a sample with swelling was rated as ×.

[0025]

According to the production method of the present invention, the interlayer adhesion between the surface layer and the intermediate layer and the uneven distribution of glass fibers in the resin of the intermediate layer of the prepreg can be solved. A composite laminate can be efficiently produced without deteriorating swelling or warpage, and without lowering the adhesion between a copper foil and a prepreg, while maintaining good electrical insulation and heat resistance. Furthermore, since the amount of solvent used and heat energy can be reduced, its industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a schematic view of a process (an example) up to manufacturing a prepreg in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass woven fabric 2 Epoxy resin varnish (a) 3 Coater 4 Dryer 5 Intermediate layer epoxy resin varnish (b) 6 Coater 7 Glass nonwoven fabric 8 Epoxy resin varnish (c) 9 Roll coater 10 Dryer 11 Cutter 12 Epoxy resin impregnated prepreg

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29K 105: 08 B29K 105: 08 B29L 9:00 B29L 9:00 31:34 31:34 F term (reference) 4F072 AA05 AA07 AB09 AB28 AC12 AE06 AF03 AF04 AF06 AG03 AG17 AH02 AH22 AJ04 AK14 AL13 4F100 AG00A AG00C AG00E AK53A AK53B AK53D AK53E BA05 BA07 BA10A BA10E CA23B CA23D DG12A DG12E DG15C EH46A EH46B EH46D EH46E EJ172 EJ422 EJ862 GB43 JL04 YY00B YY00D 4F204 AA39 AB11 AD03 AD04 AD16 AG03 AH33 AH36 FA01 FA11 FB01 FB11 FB22 FF01 FF46 FN11

Claims (3)

[Claims] 1. A step of applying an epoxy resin varnish (a) from one side of a glass woven fabric, a step of applying an intermediate layer epoxy resin varnish (b) to an epoxy resin varnish (a) application surface of the glass woven fabric, A step of laminating a glass nonwoven fabric on the surface coated with the intermediate layer epoxy resin varnish, heating and drying to prepare a prepreg, and then laminating and heat-pressing the two prepregs with the glass nonwoven fabric inside. A method for producing a composite laminate. 2. A step of applying an epoxy resin varnish (a) from one side of the glass woven fabric, a step of applying an intermediate layer epoxy resin varnish (b) to the surface of the glass woven fabric to which the epoxy resin varnish (a) is applied, After laminating a glass non-woven fabric on the surface of the intermediate layer epoxy resin varnish coating, impregnating the epoxy resin (c) from the side of the glass woven fabric, heating and drying to prepare a prepreg, A method for producing a composite laminate, comprising a step of superimposing heat and pressure molding with a nonwoven fabric inside. 3. The production of a composite laminate according to claim 1, wherein the intermediate layer epoxy resin varnish (b) contains 80 to 150 parts by weight of filler based on 100 parts by weight of epoxy resin (including a curing agent). Method.