JP3327366B2 - Manufacturing method of laminated board - Google Patents

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 laminated board suitable for a printed circuit used in electric equipment, electronic equipment, communication equipment and the like.

[Prior art]

2. Description of the Related Art Consumer electronic devices have become smaller and more sophisticated, and a printed circuit board used for the same has a structure in which a glass non-woven fabric is used as an intermediate layer base material, a glass woven fabric is used as a surface layer base material, and an epoxy resin is used. A laminated board impregnated with heat and pressure (hereinafter, referred to as a composite laminated board) is used. In recent years, such composite laminates have been required to have the same punching workability and cost reduction as paper-based phenolic laminates conventionally used in this field.

In the field of industrial electronic equipment, composite laminates which do not use glass woven fabric or reduce the amount of glass woven fabric have been used due to the need for cost reduction. It is inferior in various points to a woven fabric laminate, and it has been required to have the same dimensional change and small warpage.

In the case of composite laminates, glass non-woven fabrics are used. However, due to restrictions on non-woven fabric production, the length of the glass fibers is relatively long, and therefore the punching workability, warpage, and dimensional change are large, and this improvement is desired. I was Further, the cost of the glass nonwoven fabric is high, so that it is difficult to reduce the cost.

[0005]

SUMMARY OF THE INVENTION The present invention has been made as a result of various studies to solve the above-mentioned problems, and its object is to reduce the electrical characteristics and other various characteristics. It is an object of the present invention to provide a printed circuit board which is improved in punching workability, dimensional change, and warpage, and is low in cost.

[0006]

According to the present invention, a prepreg is prepared by coating and impregnating a thermosetting resin varnish containing glass fiber or glass fiber and an inorganic filler from one side of a long fiber base material and drying. The present invention also relates to a method for producing a laminated board, comprising laminating two sheets with the coated side inward, further arranging a metal foil on at least one side as required, and subjecting the metal foil to heat and pressure molding.

FIG. 1 is a schematic view showing an example of a method for producing a prepreg by applying a varnish containing glass fiber or glass fiber and an inorganic filler. Thermosetting resin varnish 4 in which glass fiber or glass fiber and an inorganic filler are blended on the upper surface of long substrate 2 unwound from unwinding device 1
Is dried to a predetermined thickness through a coater 5 and then cut to prepare a prepreg 7.

As the coater 2, there are a comma roll coater, a knife coater, a die coater, a reverse coater and the like. However, since the coating thickness is as thick as 0.2 to 1.0 mm, it is necessary to increase the varnish viscosity. . In consideration of impregnating the glass fiber with the resin varnish on the glass woven fabric after coating, it is better to take a certain time from coating to drying. This time is about 30 seconds to 5 minutes.

The two prepregs thus obtained are superimposed on each other with the coating side inward, and are heated and pressed. Molding conditions depend on the fluidity of the impregnated resin, but usually, as in the case of a conventional composite laminate, a temperature of 150-150.
180 ° C., pressure 30-70 kg / cm ² , time 60-1
20 minutes is appropriate.

In the present invention, the glass fiber used for the intermediate layer is a chopped strand having a length of usually 0.1 to 20 mm, preferably 1 to 7 mm. 0.1
If it is less than mm, the fiber is less entangled and the strength is reduced.
Further, if it exceeds 20 mm, the orientation of the fiber becomes remarkable,
It adversely affects dimensional changes and warpage. Fiber diameter is usually 6
-20 μm, preferably 9-13 μm. 6 μm
If the amount is less than the above, it is difficult in the production method of the glass fiber, and the cost increases. On the other hand, if it exceeds 20 μm, the fiber diameter becomes large and the punching workability deteriorates. The mixing ratio of the glass fiber to the thermosetting resin in the intermediate layer is preferably 5 to 100% by weight, more preferably 9 to 20% by weight. If the content is less than 5% by weight, the entanglement of the glass fiber is small, and the strength of the laminate is reduced.
If the content exceeds 0% by weight, the punching workability of the laminated board will be reduced. When the glass fiber used is treated with a sizing agent such as starch or urethane, or a coupling agent such as epoxysilane, the dispersibility in a resin varnish and the adhesion to a resin are improved.

Further, when an inorganic filler other than glass fiber is added to the thermosetting resin of the intermediate layer, punching workability and dimensional stability are maintained and improved, and the coefficient of thermal expansion in the Z direction is reduced. It is also possible to improve the performance. Examples of such an inorganic filler include aluminum hydroxide, calcium carbonate, clay, talc, silica, and the like, and the mixing ratio to the resin is preferably from 10 to 200% by weight. If it is less than 10% by weight, the effect of improving the reliability of the through hole is small, and if it exceeds 200% by weight, it becomes difficult to mix the inorganic filler.

The thermosetting resin used in the present invention is preferably an epoxy resin. In addition, a polyimide resin, a polyester resin, a phenol resin and the like can be used. Further, the fiber base material used for the surface layer is not particularly limited, such as glass fiber woven fabric, glass fiber nonwoven fabric, synthetic fiber woven or nonwoven fabric, kraft paper, linter paper, heat resistance,
A glass fiber woven fabric is preferred in terms of strength.

[0013]

The laminate obtained according to the present invention does not use the glass nonwoven fabric used for the conventional composite laminate in the intermediate layer, but uses glass fiber or glass fiber and an inorganic filler in a thermosetting resin. The compounded resin composition is used. Therefore, since the glass fiber having a shorter fiber length than the fiber length of the glass nonwoven fabric is used, the compounding of the resin and the glass fiber is easy, and the formed laminate has good punching workability and excellent warpage and dimensional stability. .

In the manufacturing process, the prepreg is manufactured by
A long substrate such as a glass fiber woven fabric is coated and impregnated with a thermosetting resin varnish containing glass fiber or glass fiber and an inorganic filler, and is only dried, so that it may be a relatively simple process, Therefore, it is possible to contribute to cost reduction of the laminated board. Further, although the cost of manufacturing the glass nonwoven fabric increases, the cost of the laminate according to the present invention can be further reduced because the glass nonwoven fabric is not used.

[0015]

Examples of the present invention and comparative examples (conventional examples) are described below.
Is shown. Here, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

Example 1 An epoxy resin varnish for FR-4 was prepared to have a viscosity of 30 poise (25 ° C.), and a glass fiber chopped strand (silane treatment) having a fiber length of 3 mm and a fiber diameter of 10 μm was solidified with resin. 10 per minute
%. This glass fiber-containing varnish was coated on one side of a glass woven fabric (WE-18K RB-84, manufactured by Nitto Boseki) using a comma knife roll so as to have a thickness of 0.8 mm (after drying). After air-drying for 1 minute,
It dried at 0 degreeC for 10 minutes, and produced the prepreg. The two prepregs were laminated with the coating side inside, and copper foil with a thickness of 18 μm was laminated on the upper and lower surfaces of the two prepregs.
It was heated and pressed at 65 ° C. under a pressure of 60 kg / cm ² for 90 minutes to produce a 1.6 mm-thick copper-clad laminate.

Example 2 An epoxy resin varnish for FR-4 was prepared to have a viscosity of 30 poise (25 ° C.), and a glass fiber chopped strand (silane treatment) having a fiber length of 3 mm and a fiber diameter of 10 μm was solidified with a resin solid. 10 per minute
% Of aluminum hydroxide and 70% of the resin solid content. Thereafter, a copper-clad laminate having a thickness of 1.6 mm was produced in the same manner as in Example 1.

Comparative Example 1 The epoxy resin varnish for FR-4 used in Examples was diluted to 0.3 poise with a solvent. The varnish was applied and impregnated by a dipping method on a glass woven fabric (WE-18KRB-84 manufactured by Nitto Boseki) used in the examples, and dried to prepare a prepreg for a surface layer. Then, the diluted epoxy resin varnish for FR-4 was applied to a glass nonwoven fabric (EP-4075 manufactured by Japan Vilene Co., Ltd.) by a dipping method and dried to prepare a prepreg for an intermediate layer. Next, a predetermined number of intermediate layer prepregs are stacked,
A prepreg for a surface layer was laminated on the upper and lower sides, and a copper foil having a thickness of 18 μm was laminated on both the upper and lower surfaces thereof, and heated and pressed to form a copper-clad laminate having a thickness of 1.6 mm.

<< Comparative Example 2 >> The epoxy resin varnish for FR-4 used in Examples was diluted to 0.3 poise with a solvent.
Aluminum hydroxide was blended at 70% with respect to the resin solid content. The varnish was applied to and impregnated with the glass woven fabric (WE-18K RB-84 manufactured by Nitto Boseki Co., Ltd.) by a dipping method and dried to prepare a prepreg for a surface layer. Hereinafter, a copper-clad laminate having a thickness of 1.6 mm was produced in the same manner as in Comparative Example 1.

The copper-clad laminates obtained in the above Examples and Comparative Examples were measured for punching workability, dimensional change, warpage, bending strength, and thermal expansion coefficient in the Z direction. Table 1 shows the results.
Shown in

[0021]

[Table 1]

Regarding the manufacturing cost, the method of the embodiment is simple in steps and does not use a costly glass fiber nonwoven fabric, so that the laminate obtained in the embodiment is the same as that obtained in the comparative example. The cost was reduced by about 10 to 20% as compared with the case of FIG.

[0023]

According to the method of the present invention, there is no reduction in bending strength, excellent punching workability, warpage, dimensional change, low cost, and a simple manufacturing process. It is suitable as a method.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a process up to manufacturing a prepreg in a manufacturing process of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unwinder 2 Long base material 3 Transport roller 4 Varnish 5 Coater 6 Drying device 7 Cutter 8 Prepreg

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI B29L 9:00 B29L 9:00 31:34 31:34

Claims (2)

(57) [Claims] 1. A glass fiber or a thermosetting resin varnish containing a glass fiber and an inorganic filler is applied and impregnated from one side of a long fiber base material and dried to obtain a prepreg. A method for producing a laminated board, comprising laminating two sheets and forming them under heat and pressure. 2. A prepreg is obtained by coating and impregnating a thermosetting resin varnish containing glass fiber or a glass fiber and an inorganic filler from one side of a long fiber base material and drying the prepreg. A method for producing a laminate, comprising laminating two sheets, further arranging a metal foil on at least one side thereof, and subjecting the sheet to heat and pressure molding.