JPH066629B2 - Fiber-reinforced resin composite material - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a fiber-reinforced resin composite material used for a printed wiring board for electronic devices and the like.

[Prior Art] Conventionally, as a laminated plate for electric use, a predetermined number of resin-impregnated base materials obtained by impregnating a glass cloth with a fluororesin and then heating and melting the same are laminated and molded into the glass cloth as a sizing agent. A laminated board using a material having adhered is disclosed in
No. 240743 and JP-A No. 62-161538.

As described above, when the glass cloth to which the sizing agent is attached is used as the glass cloth forming the laminate, a laminate having a low water absorption rate and a high insulation resistance after the moisture absorption treatment can be obtained.

The sizing agent is originally used for the purpose of adhering the monofilaments to each other in the production of glass fibers, when the monofilaments are aligned and formed into yarns or strands, generally, polyvinyl alcohol,
Starch, fats and oils are used.

However, after that, it became clear that the sizing agent mainly affects the insulation resistance, such as a decrease in hygroscopicity and carbonization during baking of the fluororesin, which is a problem. In order to improve this drawback, a method of using a cloth from which the above-mentioned sizing agent has been removed by heat cleaning or wet cleaning, or a method of treating this cloth with various coupling agents such as silane-based, chromium-based or titanium-based Is being considered. Particularly in the case of a composite material in which an inorganic fiber base material and a fluororesin are combined, it is said that the coupling treatment with aminosilane is preferable, and in fact, it has reached a practical level in a considerable range.

[Problems to be Solved by the Invention] However, in the composite material obtained by combining the inorganic fiber base material and the fluororesin having the above-mentioned constitution, the moisture absorption resistance is still insufficient, and the insulation resistance is lowered by the moisture absorption. Therefore, the improvement is strongly desired.

[Object of the Invention] The main object of the present invention is to further improve and improve the moisture absorption resistance of the composite material having the above structure.

Still another object of the present invention is to provide a fiber reinforced resin composite material suitable for use in a printed wiring board.

[Means for Solving the Problem] The reason why the fiber-reinforced resin composite material having the above-described configuration has poor moisture absorption resistance is due to the following points.

(1) The glass cloth has a filament diameter of 3 to 13 μm.
Since 50 to 1600 fibers of (1) are bundled and twisted to form the yarn, the fluororesin does not impregnate the monofilaments bundled in the yarn so much. That is, the fluororesin impregnated in the glass cloth is supplied in the form of an aqueous dispersion, but since the fluororesin has an average particle size of 0.2 to 0.3 μm, it is filtered outside the yarn and the monofilament inside This is because the impregnation into the resin becomes insufficient.

(2) Adhesion between the yarn and the fluororesin and the partially impregnated fluororesin and the monofilament is insufficient.

In order to solve the above problems, the inventors of the present invention conducted various research and experiments. The glass cloth was subjected to heat cleaning treatment, etc., to remove the sizing agent attached to the glass cloth, and then the fluorinated silane cup. By surface-treating the glass cloth with a ring agent, it was found that even if the impregnation of the fluororesin into the yarn was insufficient, the hygroscopic effect was suppressed, and the present invention was completed based on that finding. .

That is, the present invention is a fiber-reinforced resin composite material obtained by impregnating an inorganic fiber base material with a fluororesin, wherein a sizing agent is removed as the inorganic fiber base material, and the inorganic fiber base material is It is characterized in that the surface is surface-treated with a fluorine-based silane coupling agent.

[Operation] In the configuration of the fiber-reinforced resin composite material, since the inorganic fiber substrate is surface-treated with the fluorine-based silane coupling agent, even if the glass yarn is not sufficiently impregnated with the fluorine resin, The moisture absorption effect is suppressed by the fluorine-based silane coupling agent.

Further, the fluorine atom of the fluorine-based silane coupling agent is
As it has a good affinity (affinity) with the impregnated fluororesin,
Adhesion between the fluororesin and the inorganic fiber base material is also strengthened by the fluorosilane coupling agent.

Specific Examples of the Invention As the inorganic fiber base material used in the fiber-reinforced resin composite material of the present invention, it is desirable to use a cloth woven with plain weave of a composition generally called E glass, but the invention is not limited to this. Instead, for example, the fiber material may be an inorganic fiber generally known as an insulating material such as quartz glass, D glass, or alumina fiber, and may be not only a single use but also a blended yarn or a twisted yarn. . Further, the shape thereof is not particularly limited, and there is no problem even if it is a woven fabric, a knitted fabric, a unidirectionally aligned yarn, a mat, an alternate laminated body of these, or the like.

In order to form the fiber-reinforced resin composite material of the present invention, first, the inorganic fiber substrate is subjected to heat cleaning, washing with warm water or the like to remove the sizing agent and binder attached thereto, and then treated with a fluorine-based silane coupling agent. . The treatment method is not particularly limited, such as a method of directly applying or spraying a coupling agent, a method of treating after dissolving in water or a solvent, and a method of removing excess water or solvent by heating or depressurizing, but it is usually a base. The most commonly used method is to immerse the material in an aqueous solution of a coupling agent that has been hydrolyzed with a weakly acidic aqueous solution and dry it at 70 to 200 ° C.

Typical examples of the fluorine-based silane coupling agent include trifluorosilane represented by the following formula (1) and perfluorosilane represented by the following formula (2), but at least one or more of them may be contained in one molecule. Any silane coupling agent containing fluorine molecules may be used.

However, R ₁ , R ₂ and R ₃ are CnH _{2n + 1} and OCnH _{2n + 1} (n
= 1-5) or Cl m = 0-9, p = 1-9 The amount of the fluorine-based silane coupling agent attached is 0.2.
The optimum value is ˜2.0 wt%. Incidentally, it is of course possible to add a surfactant or another additive to the stock solution or aqueous solution of the fluorine-based silane coupling agent.

The surface-treated inorganic fiber substrate thus obtained was impregnated with a fluororesin dispersion, and then the resin was added to 270 to 40.
Heat and melt at 0 ° C. By repeating this impregnation-heating and melting as necessary, a resin-impregnated base material containing a predetermined amount of resin is obtained.

Further, in the case of forming an electrical laminate using the resin-impregnated base material, a predetermined number of the resin-impregnated base material obtained in the above step is laminated together with a fluororesin film, and copper foil is provided on one side or both sides thereof. Etc. Metal foils such as the above are laminated to form a laminated body, and the laminated body is subjected to a molding pressure of 3 to 130 kg /
cm ^2, molding temperature 270 to 400 ° C. at 3 to 200 minutes, to obtain a heat and pressure molded into laminates.

As the fluororesin dispersion, a tetrafluoroethylene resin (PTFE) dispersion, a tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) dispersion, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin ( PFA) dispersion or the like is used.

As the fluororesin film to be laminated with the resin-impregnated base material, PTFE film, FEP film, PF
A film or the like is used.

When the inorganic fiber substrate is impregnated with a fluororesin dispersion, the solid content concentration of the fluororesin dispersion varies depending on the lot, or the viscosity changes due to temperature or aging, so the amount impregnated into the inorganic fiber substrate is It is difficult to obtain a resin-impregnated base material that varies and has a uniform thickness, but as described above, by changing the number of laminated fluororesin films according to the thickness of the resin-impregnated base material, an electrical laminate having a uniform thickness can be obtained. Easily obtained.

In particular, in the case of electrical laminates, the uniformity of the thickness as well as the uniformity of the dielectric constant are strongly demanded, and therefore, those satisfying both of them are required. In the use of the resin-impregnated base material, if there is a variation in the thickness of the base material, the resin content of the laminate will vary, and the dielectric constant will also vary, but according to the use of the fluororesin film, , The above problem does not occur.

In addition, after impregnating the inorganic fiber substrate with a fluororesin dispersion and heating and melting it, further tetrafluoroethylene-
A hexafluoropropylene copolymer resin (FEP) dispersion or a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA) dispersion impregnated and heated and melted can be used.

FEP dispersion on the resin-impregnated substrate as described above,
Alternatively, in the case where the PFA dispersion is further impregnated and heated and melted, the adhesion between the resin-impregnated base material and the resin-impregnated base material and the PTFE film can be improved, and the moisture absorption resistance can be improved. Further, since FEP and PFA are fluororesins showing melt fluidity, excellent adhesiveness can be obtained by heat and pressure molding.

[Examples and Comparative Examples] Example (1) A glass cloth having a thickness of 0.05 mm was subjected to a heat cleaning treatment to remove a sizing agent and the like, and then a fluorinated silane coupling agent [CF ₃ CH ₂ CH 2 with a concentration of 2 wt% was used. ₂ Si (OCH ₃ ) ₃ ] aqueous solution, passed through a squeeze roll, and dried at 110 ° C. to obtain a surface-treated glass cloth. At this time, the amount of the fluorine-based silane coupling agent attached after drying was adjusted to 0.8 wt% by adjusting the squeezing roll.

The glass cloth obtained as described above was impregnated with a tetrafluoroethylene resin dispersion, and then 370
It was heated and melted at ℃. After repeating this impregnation-heating and melting five times, it was further impregnated with FEP dispersion and then heated and melted at 340 ° C. to give a resin content of 68%.
To obtain a resin-impregnated base material.

As shown in FIG. 1, 10 pieces of this resin-impregnated base material, 4 pieces of tetrafluoroethylene resin film having a thickness of 25 μm, and 2 pieces of copper foil having a thickness of 18 μm were overlaid, and a molding pressure of 70 kg /
cm ^{2 at} a molding temperature of 380 ° C. for 90 minutes under heat and pressure,
An electrical laminate having a pressure of 0.8 mm was obtained. In the drawings, 1
Is a resin-impregnated base material, 2 is a tetrafluoroethylene resin film,
3 is a copper foil.

According to JIS C6481, the laminated plate obtained by the above process,
After soaking in boiling water at 100 ° C. for 2 hours (D-2 / 100 treatment), the insulation resistance was measured, and the water absorption rate (D-2 / 10
Table 1 shows the measurement results of (after 0 treatment).

Comparative Example (1) The procedure of Example (1) was repeated, except that the heat cleaning treatment and the fluorine-based silane coupling agent treatment were not performed, and the glass cloth with the sizing agent attached was used.
Table 1 shows the measurement results of the obtained laminated plate.

Comparative Example (2) A glass cloth that has been subjected to heat cleaning treatment to remove the sizing agent (without treatment with a fluorine-based silane coupling agent)
The same procedure as in Example (1) was performed except that was used. Table 1 shows the measurement results of the obtained laminated plate.

Comparative Example (3) After heat cleaning treatment, surface treatment with vinyltrimethoxysilane [CH ₂ = CHSi (OCH ₃ ) ₃ ] (deposition amount 0.3 wt%)
The same procedure as in Example (1) was performed except that the glass cloth was used. The first is the result of the measurement performed on the obtained laminated plate.
Shown in the table.

Comparative Example (4) Other than using a glass cloth surface-treated with γ-aminopropyltriethoxysilane [NH ₂ C ₃ H ₈ Si (OC ₂ H ₅ ) ₃ ] (deposition amount: 0.3 wt%) after heat cleaning. Was performed in the same manner as in Example (1). Table 1 shows the measurement results of the obtained laminated plate.

Example (2) A glass cloth having a thickness of 0.05 mm was heat-cleaned to remove a sizing agent and the like, and then a fluorine-based silane coupling agent [CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) _{3 having} a concentration of 4 wt% was used. ] It was immersed in an aqueous solution, passed through a squeeze roll, and then dried at 120 ° C. to obtain a surface-treated glass cloth. At this time, the squeeze roll was adjusted to change the amount of the fluorine-based silane coupling agent attached after drying.

Each glass cloth obtained as described above was impregnated with a tetrafluoroethylene resin dispersion and then heated and melted at 370 ° C. This impregnation-melting by heating was repeated 4 times, and then further impregnated with FEP dispersion. Then, it was heated and melted at 340 ° C. to obtain a resin-impregnated base material having a resin amount of 67%.

As shown in FIG. 2, 10 pieces of this resin-impregnated base material, 5 pieces of 25 μm thick tetrafluoroethylene resin film, and 2 pieces of 18 μm thick copper foil were overlaid, and the molding pressure was 50 kg / cm.
^2. Heat and pressure molding was performed at a molding temperature of 400 ° C. for 60 minutes to obtain a laminated plate having a thickness of 0.8 mm. The reference numerals in the drawing are the same as those in FIG.

The laminated board obtained in the above process is 100 according to JIS C6481.
After soaking in boiling water at ℃ for 2 hours (D-2 / 100 treatment),
Table 2 shows the results of measuring the insulation resistance and the water absorption rate (after the treatment of D-2 / 100).

[Advantages of the Invention] As described above, according to the present invention, a fiber-reinforced resin composite material obtained by impregnating an inorganic fiber base material with a fluororesin, wherein a sizing agent is removed as the inorganic fiber base material. Is used, and since the surface of the inorganic fiber substrate is surface-treated with a fluorine-based silane coupling agent, due to the water repellency of the fluorine-based silane coupling agent, the fluororesin is contained in the yarn of the inorganic fiber substrate. Even if the impregnation is insufficient, the moisture absorption is suppressed, and the adhesion between the fluororesin and the inorganic fiber base material is strengthened by the fluorosilane coupling material. Therefore, the conventional fluororesin dispersion-impregnated glass cloth is used. It is possible to obtain a fiber-reinforced resin composite material with significantly improved moisture absorption resistance as compared with a laminated plate or the like.

In particular, according to the present invention, it is possible to easily obtain an electrical laminated plate which is required to have a uniform thickness and a uniform dielectric constant.

[Brief description of drawings]

FIG. 1 and FIG. 2 are explanatory views schematically showing the constitution when the present invention is applied to an electric laminate. 1 ... Resin impregnated substrate, 2 Tetrafluoroethylene resin film, 3 Copper foil.

Claims (3)

[Claims] 1. A fiber-reinforced resin composite material obtained by impregnating an inorganic fiber base material with a fluororesin, wherein the sizing agent is removed as the inorganic fiber base material, and the surface of the inorganic fiber base material is used. Is a surface-treated with a fluorine-based silane coupling agent, which is a fiber-reinforced resin composite material. 2. A resin impregnation obtained by using a glass cloth from which a sizing agent has been removed on an inorganic fiber base material, surface-treating it with a fluorine-based silane coupling agent, further impregnating it with a fluororesin dispersion, and heating and melting it. A fiber-reinforced resin composite material used for an electrical laminate, which is obtained by stacking a predetermined number of base materials together with a fluororesin film, and further stacking a metal foil on one side or both sides of the base and heat-pressing. 3. A glass cloth from which a sizing agent has been removed is used as an inorganic fiber base material, which is surface-treated with a fluorinated silane coupling agent, then impregnated with a fluororesin dispersion and heated and melted. A predetermined number of resin-impregnated base materials, which are obtained by impregnating a fluoroethylene-hexafluoropropylene copolymer copolymer resin dispersion or a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin dispersion and heating and melting, are laminated with a fluororesin film. A fiber-reinforced resin composite material used for an electrical laminate, which is obtained by combining and further heating and pressing metal foil on one side or both sides.