JPH04122734A - Fiber-reinforced resin composite material - Google Patents

Abstract

PURPOSE:To obtain the title material improved in moisture absorption resistance and desirable as a printed wiring board for electronic devices, etc., by impregnating an inorganic fiber base surface-treated with a phenylsilane coupling agent with a fluorocarbon resin. CONSTITUTION:An inorganic fiber base, e.g. a glass cloth is surface-treated with a phenylsilane coupling agent of the formula: XnSiR4-n (wherein X is phenyl, and R is 1-5C alkoxy or chloro) and impregnated with a fluorocarbon resin dispersion, and the resin is molten by heating to obtain a fiber-reinforced resin composite material. The amount of the coupling agent adhered is 0.2-5.0wt.% based on the inorganic fiber base.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in fiber-reinforced resin composite materials used in printed wiring boards for electronic devices and the like.

[Prior Art] Conventionally, an electrical laminate is produced by laminating and molding a predetermined number of resin-impregnated base materials in a heat press by impregnating a glass cloth with a fluororesin and then heating and melting the resin-impregnated base material. A laminated board using laminates with
-240743 and Japanese Unexamined Patent Publication No. 161538/1983.

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

The above-mentioned sizing agent is originally used for the purpose of adhering the monofilaments to each other when aligning the monofilaments to form a yarn or strand in the production of glass fibers, and generally includes polyvinyl alcohol,
Starch, oil, etc. are used.

However, it has since become clear that the above-mentioned sizing agent has an adverse effect mainly on insulation resistance, such as a decrease in moisture absorption resistance and carbonization during firing of the fluororesin, which has become a problem. In order to improve this drawback, there is 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.

In particular, for composite materials combining an inorganic fiber base material and a fluororesin, coupling treatment with aminosilane is considered preferable, and in fact has reached a practical level to some extent.

[Problem M to be solved by the invention] However, the composite material combining the inorganic fiber base material and the fluororesin having the above structure still has insufficient moisture absorption properties, and the insulation resistance decreases due to moisture absorption. Therefore, improvement thereof is strongly desired. [Object of the Invention] The main object of the present invention is to further 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 printed wiring boards.

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

(1) Glass cloth has a filament diameter of 3 to 13 μm.
Because it is made using yarns made by bundling 50 to 1,600 fibers together and twisting them, fluororesin does not impregnate much of the monofilament bundled into the yarns. That is, the fluororesin that is impregnated into 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 on the outside of the yarn, and the monofilament inside. (2) The adhesion between the yarn and the fluororesin and between the partially impregnated fluororesin and the monofilament is insufficient.

In order to solve the above problem, the present inventors conducted various research experiments and found that after applying a heat cleaning treatment etc. to the glass cloth to remove the sizing agent attached to the glass cloth, the glass cloth was vs. 0.2~5.0w
It was discovered that by surface-treating the glass cloth with a phenylsilane coupling agent so that the amount of adhesion is 1.5t%, the moisture absorption effect can be suppressed even if the fluororesin permeates into the yarn insufficiently. The present invention was completed based on this knowledge.

That is, the present invention provides a fiber-reinforced resin composite material formed by impregnating an inorganic fiber base material with a fluororesin, in which the surface of the Moeki inorganic fiber base material is 0.2 to 5.0 wt% relative to the glass cloth.
It is characterized in that the surface is treated with a phenylsilane coupling agent so that the amount of adhesion is as follows.

[Function] In the above structure of the fiber-reinforced resin composite material, the surface of the inorganic fiber base material is surface-treated with a sufficient amount of the phenylsilane coupling agent, so that impregnation of the fluororesin into the glass yarn is prevented. Even if sufficient, the phenylsilane coupling agent suppresses the hygroscopic effect.

Furthermore, since the phenylsilane coupling agent has good compatibility with the fluororesin to be impregnated, the adhesion between the fluororesin and the inorganic fiber base material is also strengthened by the phenylsilane coupling agent. However, if the amount of treatment is too large, it is thought that the adhesion between the fluororesin and the inorganic fiber base material deteriorates, resulting in moisture absorption.

[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 cloth made by plain-weaving yarn with a composition called E-glass for boat fishing, but it is not limited to this. For example, the fiber material may be any inorganic fiber that is commonly known as an insulating material, such as quartz glass, D-glass, or alumina fiber, or it may be used not only alone but also as a blend or twisted yarn. do not have. Further, its shape is not particularly limited, and there is no problem in using not only woven fabrics but also knitted fabrics, unidirectionally aligned threads, mats, and alternate laminates thereof.

To form the fiber-reinforced resin composite material of the present invention, the inorganic fiber base material is first removed by heat cleaning or hot water washing to remove the sizing agent and binder, and then treated with a phenylsilane coupling agent. . The treatment method is not particularly limited, such as directly applying or spraying the coupling agent, or dissolving it in water or a solvent and then removing excess water and solvent by heating or reducing pressure. The most commonly used method is to impregnate the material with an aqueous solution of a coupling agent hydrolyzed in a weakly acidic aqueous solution and dry it at 70 to 200°C.

The phenylsilane coupling agent has the general formula (%), where x is C6H5, R is OCmHzm+t (m=
1 to 5) or CQ, are used.

For example, phenyltrimethoxysilane C6H55i (
OCH3)3, phenyltriethoxysilane C6t(
55i(OC2Hs)3, diphenyldimethoxysilane (C6H5)2Si(OCH3)3, phenyltrichlorosilane C6H5SlcQ3, and the like.

The amount of the phenylsilane coupling agent deposited must be 0.2 to 5.0 wt% in order to obtain sufficient moisture absorption resistance. Outside this range, the moisture absorption resistance is insufficient and the insulation resistance decreases significantly due to moisture absorption.

Note that it is of course possible to add surfactants and other additives to the stock solution or aqueous solution of the phenylsilane coupling agent.

After impregnating the surface-treated inorganic fiber base material thus obtained with fluororesin dispersion, the resin was
Heat and melt at 0°C. By repeating this impregnation-heat-melting process as necessary, a resin-impregnated base material containing a predetermined amount of resin is obtained.

Furthermore, when constructing an electrical laminate using the resin-impregnated base material, a predetermined number of resin-impregnated base materials obtained in the above process are laminated together with a fluororesin film, and a copper foil is coated on one or both sides of the resin-impregnated base material. etc. are overlapped to form a laminate, and this laminate is heat pressed at a molding pressure of 3 to 130 kg.
/CIII, heat and pressure molding is performed at a molding temperature of 270 to 40° C. for 3 to 200 minutes to obtain a laminate.

The fluororesin dispersions include tetrafluoroethylene resin (PTFE) dispersion, tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) dispersion, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA). ) disversion etc. are used.

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

When impregnating the inorganic fiber base material with fluororesin dispersion, the solid content concentration of the fluororesin dispersion varies depending on the lot, and the viscosity changes depending on temperature and changes over time, so the amount of impregnation into the inorganic fiber base material may vary. Although it is difficult to obtain a resin-impregnated base material with a uniform thickness, it is possible to obtain an electrical laminate with a uniform thickness by changing the number of laminated fluororesin films depending on the thickness of the resin-impregnated base material, as described above. easily obtained.

Particularly in the case of electrical laminates, uniformity in thickness and uniformity in dielectric constant are strongly required, so a material that can satisfy both is required. When using the above-mentioned resin-impregnated base material, if there is variation in the thickness of the base material, the resin content of the laminate will vary and the dielectric constant will also vary. Otherwise, the above problem will not occur.

[Example and Comparative Examples Example (1) After heat cleaning a glass cloth with a thickness of 0.05 mm to remove the sizing agent, etc., a phenylsilane coupling agent [C6Hs 5i ( O.C.
H3) 3 ] After immersed in an aqueous solution and passed through a squeezing roll 1
It was dried at 10°C. By performing this immersion-drying process twice, the amount of phenylsilane coupling agent deposited is reduced to 0.
A 62 wt % surface treated glass cloth was obtained.

The glass cloth obtained as described above was impregnated with tetrafluoroethylene resin dispersion, and then
It was melted by heating at ℃. This impregnation-heat-melting process was repeated five times to obtain a resin-impregnated base material with a resin content of 68%.

Ten sheets of this resin-impregnated base material, four sheets of polytetrafluoroethylene resin film with a thickness of 25 μm, and two sheets of copper foil with a thickness of 18 μm were stacked together as shown in Figure 1, and a molding pressure of 70 kg was applied.
Z: Heat and pressure mold at a molding temperature of 380℃ for 90 minutes,
An electrical laminate having a thickness of 0.8M was obtained. In addition, in one drawing, l
2 is a resin-impregnated base material, 2 is a tetrafluoroethylene resin film,
3 is copper foil.

The laminate obtained by the above process is JIS C6481
Soaked in boiling water at 100°C for 2 hours (D2/1.
00 treatment), the insulation resistance was measured and the water absorption rate (D-2
/100 after treatment) and the results are shown in Table 1.

Comparative Example (1) The same procedure as in Example (1) was carried out except that the heat cleaning treatment and the phenylsilane coupling agent treatment were not performed, and the glass cloth with the sizing agent still attached was used. The measurement results performed on the obtained laminate are
Shown in the table.

Comparative Example (2) The same procedure as in Example (1) was carried out except that a glass cloth (not treated with a phenylsilane coupling agent) which had been heat-cleaned to remove the sizing agent was used. Table 1 shows the results of measurements performed on the obtained laminate.

Comparative Example (3) After heat cleaning, N-phenyl-γ-aminopropyltrimethoxysilane [C6H5NHC3H65i(
The same procedure as in Example (1) was carried out except that a glass cloth surface-treated with OCH3) (adhesion amount: 0.32 t%) was used. Table 1 shows the results of measurements performed on the obtained laminate.

Example (2) [Including Comparative Example] After heat cleaning a glass cloth with a thickness of 0.05 mm to remove the sizing agent, etc., a phenylsilane coupling agent [C6H55L (OCH
3) 3] After immersed in an aqueous solution and passed through a squeezing roll 12
It was dried at 0°C. Adjustment of squeezing roll and soaking-drying 1
The amount of phenylsilane coupling agent deposited after drying was varied by repeating the drying process ~4 times.

Each of the glass cloths obtained as described above was impregnated with a tetrafluoroethylene resin dispersion, and then heated and melted at 360'C.

This impregnation and heating melting process was repeated 5 times until the amount of resin was 6.
A 7% resin impregnated substrate was obtained.

Ten sheets of this resin-impregnated base material, five sheets of polytetrafluoroethylene resin film with a thickness of 25 μm, and two sheets of copper foil with a thickness of 18 μm were stacked together as shown in Figure 2, and a molding pressure of 50 kg/
d. Heat and pressure molding was performed at a molding temperature of 390° C. for 60 minutes to obtain a laminate with a thickness of 0.8 mm. The reference numerals in the drawings are the same as in FIG.

According to JIS C6481, the laminate obtained in the above process was immersed in boiling water at 100°C for 2 hours (D-2/100 treatment), then the insulation resistance was measured and the water absorption rate (D-2/10
Table 2 shows the results of the measurements (after 0 treatment).

Table [Effects of the Invention] As described above, according to the present invention, in a fiber-reinforced resin composite material formed by impregnating an inorganic fiber base material with a fluororesin, the surface of the inorganic fiber base material is phenylsilane-based. Since the surface is treated with a coupling agent, the non-hygroscopic property of the phenylsilane coupling agent prevents moisture absorption even if the fluororesin is insufficiently impregnated into the yarn of the inorganic fiber base material. At the same time, since the adhesion between the fluororesin and the inorganic fiber base material is also strengthened by the phenylsilane coupling agent, moisture absorption resistance is significantly improved compared to conventional fluororesin dispersion-impregnated glass cloth laminates. A fiber-reinforced resin composite material can be obtained.

In particular, according to the present invention, it is possible to easily obtain an electrical laminate that requires uniformity in thickness and uniformity in dielectric constant.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are explanatory diagrams each schematically showing a configuration in which the present invention is applied to an electrical laminate. l...Resin-impregnated base material, 2...
...Tetrafluoroethylene resin film, 3...
··Copper foil. Patent applicant NICHIAS Co., Ltd.

Claims (2)

[Claims] (1) In a fiber-reinforced resin composite material formed by impregnating an inorganic fiber base material with a fluororesin, the surface of the inorganic fiber base material has the general formula OC_mH_2_m_
The surface has been treated with a phenylsilane coupling agent represented by Characteristic fiber-reinforced resin composite material. (2) Glass cloth is used as the inorganic fiber base material, and the general formula XnSiR_4_-_n (n=1 to 3) is used.
The surface of the glass cloth is treated with a phenylsilane coupling agent represented by +_1 (m=1 to 5) or Cl so that the adhesion amount is 0.2 to 5.0 wt%, and then fluororesin dispersion is applied. A fiber-reinforced material used in electrical laminates, which is obtained by laminating a predetermined number of resin-impregnated base materials impregnated and heated and melted with a fluororesin film, and then laminating metal foil on one or both sides and forming them under heat and pressure. Resin composite material.