JP2752159B2 - Method for producing inorganic fiber woven fabric for laminate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an inorganic fiber fabric used as a reinforcing material for a resin laminate used for a printed wiring board and the like. More specifically, the present invention relates to a method for producing an inorganic fiber woven fabric suitable for obtaining a laminate having low hygroscopicity and extremely good heat resistance after moisture absorption.

[Conventional technology]

Resin laminates reinforced with inorganic fiber fabrics are becoming increasingly important as various structural materials and printed wiring boards. Conventionally, a laminated board using glass cloth has been used for industrial printed wiring boards that require high performance, and in fields where cost and workability are important, kraft paper and glass paper have been used. A so-called composite type laminated plate made of a sandwich is used. The insulation properties of printed wiring boards and the heat resistance after moisture absorption are closely related to the moisture absorption behavior of the boards, but in recent years, as the densification, multilayering, and thinning have progressed, laminates with even less hygroscopicity Boards have come to be desired.

Many attempts have been made to reduce the moisture absorption of laminated boards, but all of these have focused on improving the matrix resin used in the laminated board, or modifying the interface between the fiber and the resin, or improving the molding method. Met. For example, glass cloth generally used as a base material of a laminated board is generally used after being treated with a silane coupling agent or the like.By optimizing the type of the silane coupling agent and the application conditions to the fiber surface, Attempts have been made to reduce the moisture absorption of laminates by modifying the interface (Robert J. Boudreau
“Glass Fabric Finishes: Effects on the kinetics of
water absorption and laminate physical and electr
ical propeties "THE 3RD PRINT CIRCUIT WORLD CONVENT
ION, 1981, pp. 230-238). This is because the silane coupling agent is considered to react with the glass surface and the matrix resin to form a bridge between the two, thereby preventing intrusion of moisture into the interface. However, it has been difficult to significantly improve the conventional processing agents and methods for improving the processing conditions.

Attempts have also been made to obtain a laminate having low hygroscopicity by making the prepreg as free of bubbles as possible (Japanese Patent Application Laid-Open No. 64-6653). 194252), a method of exposing a liquid-containing inorganic fiber woven fabric to reduced pressure
175165) or a method of directly contacting the ultrasonic vibrator with the woven fabric (Japanese Patent Laid-Open No. 62-257461) is a study of this method from the woven fabric side.

Furthermore, a method of reducing the pressure during varnish impregnation (Japanese Patent Publication No. 64-66)
53) Attempts have also been made to reduce voids in the laminate by vacuum defoaming during lamination, thereby improving moisture absorption and heat resistance. However, it has been difficult to significantly improve the hygroscopicity of the laminate even by such a method.

[Problems to be solved by the invention]

The present invention reduces the moisture absorption of the conventional resin laminate, thereby improving heat resistance, insulation, and delamination after moisture absorption, and has excellent electrical properties and heat resistance. It is an object of the present invention to provide a method for producing the same.

[Means for solving the problem]

The present inventors have conducted intensive studies to solve the above-described problems, and as a result, in a laminate using an inorganic fiber woven fabric as a reinforcing material, a woven fabric having a specific structure has a very low moisture absorption rate. The inventors have found that the present invention can be performed, and have reached the present invention.

The present invention relates to an inorganic fiber fabric woven using an inorganic fiber yarn having a fabric thickness of 0.25 mm or less and a filament diameter of 3 μm to 11 μm, and its specific air permeability in a heat cleaning state. X is 1.5 × 10 ^-2 (cm ³ / cm ² · s
ec) It is intended to provide a method for producing an inorganic fiber woven fabric for a laminate characterized by the following.

[Here, the specific air permeability X is represented by the following equation.

X = A · M A: Permeability per cm ² (unit: cm ³ / cm ² · sec) determined by JIS-L1096 “Permeability test A method” M: Volume in glass bulk conversion per 1 cm ^{2 of} woven fabric ( Unit: c
m) M = w / ρ ρ: Specific gravity of the inorganic material (unit: g / cm ³ ) w: weight per 1 cm ^{2 of the} woven fabric (unit: g / cm ² )] An inorganic fiber woven fabric having a thickness of 0.25 mm or less composed of inorganic fibers having a filament diameter of 3 to 11 μm is treated with a fluid pressure wave or a high-pressure columnar flow after greige or heat cleaning to defibrate the yarn constituting the fabric. After that, the defibrated woven fabric is subjected to pressure melting treatment to 1.5 × 1
It can be obtained by preparing a heat-cleaning treated fabric having a specific air permeability X of 0 ^-2 cm ³ / cm ² · sec or less.

As the inorganic fiber fabric of the present invention, E glass, C glass,
Glass fibers such as S glass, D glass, and quartz, and ceramic fibers such as alumina can be used. The filaments constituting these fibers preferably have a diameter of 3 μm to 11 μm. Inorganic fibers having a diameter of less than 3 μm are generally rarely used for laminates. Also 11μm
Larger ones are not preferred, especially as a laminate for a printed circuit board, because the drillability and surface smoothness are reduced.

The inorganic fiber woven fabric used in the present invention basically comprises a warp and a weft, and is obtained by pasting a yarn obtained by bundling a plurality of the above filaments and then weaving,
For example, plain weave, twill weave, satin weave and the like.
Organic materials such as starch are attached to these woven fabrics to protect the fibers, but after being woven, they are removed by heat treatment or the like, and then surface-treated with a treating agent such as a silane coupling agent before use. On the other hand, using resin and cupping agent for glue,
The woven cloth can be used as it is as a base cloth for a laminated board.

In the present invention, the thickness of the inorganic fiber fabric is preferably in the range of 0.25 mm. As a result, a laminate using a thick inorganic fiber woven fabric has a specific air permeability of 1.5 × 10 ^-2 (cm ³
/ Cm ² · sec) or less, the resin is not easily impregnated into the woven fabric, and the residual air bubbles are likely to remain inside the fiber bundle. As a result, it becomes difficult to obtain a laminate having a low moisture absorption rate, which is not preferable. The specific air permeability is the air permeability of a fabric per unit volume. For example, the air permeability of a style 7628 (manufactured by Asahi Schwebel) having a weight of 205 g per square meter in an E glass fiber fabric is 10 (cm ³ / cm ^2. In the case of (sec), the specific gravity of E glass is 2.54, so the specific air permeability is 8 × 10 ^-2 (cm ³
/ Cm ² · sec). Specific air permeability is the type of yarn, the form of yarn,
The number varies depending on the number of drivings, the fabric structure, and the like. In general, the larger the number of drivings is, the thinner the yarn is, the smaller the number becomes.

A good observation of the moisture absorption behavior of the laminate shows that a large percentage of moisture penetrates from the surface of the laminate. When the laminated board is rapidly heated with solder or the like after absorbing moisture, moisture evaporates and expands between the layers, causing delamination. However, surprisingly, when the specific air permeability of the inorganic fiber fabric is 1.5 × 10 ^-2 (cm ³ / cm ² · sec) or less, it is thought that the penetration of water into the interior of the laminate is suppressed by the fabric. Then, the rate of moisture absorption into the laminate decreases sharply. The relationship between moisture absorption and specific air permeability is not primary,
Above 1.5 × 10 ^-2 (cm ³ / cm ² · sec), the rate of moisture absorption increases sharply at locations larger than this.

The inorganic fiber woven fabric of the present invention is, for example, a thermosetting resin such as an epoxy resin, a polyimide resin, an unsaturated polyester resin, and a phenolic resin, or a laminated board having a matrix of a thermoplastic resin such as a polyphenylene sulfide resin and a forryphenylene ether resin. It is also suitably used especially for copper-clad laminates used for printed circuit boards.

Such an inorganic fiber woven fabric is difficult to achieve simply by weaving the inorganic fibers, and can be prepared by applying the above-described method to the woven fabric. Examples of the method include a method in which a pressure wave of a fluid or a high-pressure columnar flow is applied to a woven fabric, the constituent yarns are sufficiently defibrated, and then compressed by a press roll or the like. As the fluid, for example, water, hot water, a liquid such as alcohol or acetone, or a gas such as air, nitrogen, or helium is used. From the viewpoint of safety and equipment, water and air are preferable. The pressure wave is preferably a dynamic one that periodically repeats compression and expansion,
The cycle of compression and expansion is not particularly limited, but is preferably 50 cycles / second or more. The defibration by the columnar flow can also be performed by a generally well-known method. However, only the defibration process has a specific air permeability.
It is difficult to achieve 1.5 × 10 ^-2 (cm ³ / cm ² · sec) or less, and it is necessary to prepare a woven fabric having the above specific air permeability by applying a combination with press working with a compression roll or the like. Can be. To make it easier to achieve, it is also possible to use a woven fabric using a low twist number yarn.
Of course, whatever the method, the specific air permeability is 1.5 × 10 ^-2
(Cm ³ / cm ² · sec) or less is an inorganic fiber woven fabric which meets the purpose of the present invention.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to examples.

Example-1 Style 7628 made by Asahi Schwebel (ECG75 1/0 yarn composed of 400 filaments having a diameter of 9 μm and made of E glass was used as a warp weft;
This, glass cloth) with an average thickness of 0.185mm in m ² per weight 205g, 700 revolutions / vibro washer running in minutes (long wave universal washing machine, when desizing part through Daiwa Kikai Co., Ltd.) Simultaneously, the fiber was defibrated and squeezed and dried at high pressure with a rubber roll. Next, the paste was completely heat cleaned at 400 ° C. for 60 hours by batch opening. Then 1%
The glass cloth was immersed in epoxy silane (SZ-6040 made by Toray Silicon), and dried to obtain a surface-treated glass cloth. The air permeability A of this cloth is 1.5 (cm ³ / cm ² · se
In c), since the specific gravity of E glass is 2.54, the specific air permeability is 1.2 × 10
⁻² (cm ³ / cm ² · sec). Further, the cloth from which the silane coupling agent was removed again by heat cleaning also had an air permeability of A1.5 (cm ³ / cm ² · sec) and a specific air permeability of 1.2 × 10 2.
^-2 (cm ³ / cm ² · sec).

Next, a hardener containing Br of 65% resin amount is added to the treated glass cloth.
After impregnated with a fluorinated epoxy resin varnish, heat devolatilize to create a prepreg, stack four prepregs, lay copper foil on both sides, press-mold and etch out the copper foil, 0.8mm
A laminate having a thickness was obtained.

Example 2 A glass cloth 7628 was heat-cleaned by an ordinary method, and the glass cloth was subjected to a surface treatment in the same manner as in Example 1. The cloth was exposed to a water jet having a water pressure of 30 kg / cm ² and then exposed to a squeeze roll. High pressure press dewatering and drying, air permeability A is 1.7 (cm ³ / cm ² · sec), therefore specific air permeability 1.4 × 10
A glass cloth of ⁻² (cm ³ / cm ² · sec) was obtained. The cloth was heat-cleaned again and the air permeability was measured. The air permeability A of the cloth was 1.7 (cm ³ / cm ² · sec), and the specific air permeability was 1.4 × 10 ^-2 (cm ³ / cm ² · sec). Was equivalent to the treated cloth. Using this treated cloth, a laminate was obtained in the same manner as in Example 1.

Comparative Example 1 A surface-treated glass cloth was obtained in the same manner as in Example 1, except that the rotation speed of the vibro-wafer was operated at 300 rpm. Air permeability A of treated cloth and cloth from which the silane coupling agent has been removed by heat cleaning
Is 2.2 (cm ³ / cm ² · sec) and the specific permeability is 1.8 × 10 ^-2 (cm ³ /
cm ² · sec). Using this treated cloth, a laminate was obtained in the same manner as in Example 1.

Comparative Example 2 A glass cloth 7628 was heat-cleaned by an ordinary method to obtain a surface-treated glass cloth in the same manner as in Example 1. The air permeability A of the treated cloth and the cloth from which the silane coupling agent has been removed by heat cleaning is 10
(Cm ³ / cm ² · sec), specific air permeability is 8.1 × 10 ^-2 (cm ³ / cm ² ·
sec). Using this treated cloth, a laminate was obtained in the same manner as in Example 1.

Example-3 Style 216 manufactured by Asahi Schwebel Co., Ltd. (ECE225 1/0 yarn consisting of 200 filaments of 7 μm in diameter of E glass was used for the warp weft, the number of 25 mm drive was 60 warp and 58 wefts)
This, glass cloth) with an average thickness of 0.100mm in m ² per weight 100 g, 700 rev / vibro washer running in minutes (long wave universal washing machine, when desizing part through Daiwa Kikai Co., Ltd.) Simultaneously, the fiber was defibrated and squeezed and dried at high pressure with a rubber roll. Next, a glass cloth surface-treated in the same manner as in Example 1 was obtained. The air permeability A of this cloth is 2.8
(Cm ³ / cm ² · sec) and the specific gravity of E glass was 2.54, so the specific air permeability was 1.1 × 10 ^-2 (cm ³ / cm ² · sec). The cloth from which the silane coupling agent was removed by heat cleaning again had the same air permeability of 2.8 (cm ³ / cm ² · sec) and a specific air permeability of 1.1 × 10 ^-2 (cm ³ / cm ² · sec).

Next, a prepreg was prepared in the same manner as in Example 1, six prepregs were laminated, copper foils were laminated on both surfaces of the prepregs, and the copper foil was etched out after press molding to obtain a laminate having a thickness of 0.6 mm.

Comparative Example-3 The glass cloth 216 was heat-cleaned by an ordinary method to obtain a surface-treated glass cloth in the same manner as in Example-3. The air permeability A of the treated cloth and the cloth from which the silane coupling agent has been removed by heat cleaning is 40.
(Cm ³ / cm ² · sec), specific air permeability is 15.7 × 10 ^-2 (cm ³ / cm ²
Sec). Using this cloth, a laminated board was obtained in the same manner as in Example 1.

Comparative Example-4 Style 2523 manufactured by Asahi Schwebel (diameter of E glass
ECH25 1/0 yarn consisting of 800 10.5μm filaments is used for the warp weft.
20 pieces, glass cloth with an average thickness of 0.350 mm with a weight of 380 g per m ² and a mean thickness of 0.350 mm are partially de-sized through a vibro washer (a long-wave universal washing machine, manufactured by Daiwa Machine Co., Ltd.) operating at 700 rpm. At the same time, the mixture was defibrated and squeezed and dried at high pressure with a rubber roll. Next, a glass cloth surface-treated in the same manner as in Example 1 was obtained. The air permeability A of this cloth is 0.
85 (cm ³ / cm ² · sec), specific air permeability is 1.3 × 10 ^-2 (cm ³ / cm ²
Sec). In addition, the cloth whose silane coupling agent has been removed by heat cleaning again has an air permeability of 0.85.
(Cm ³ / cm ² · sec), specific air permeability 1.3 × 10 ^-2 (cm ³ / cm ² · se
Same in c). Next, a prepreg was prepared in the same manner as in Example 1, four prepregs were laminated, copper foil was laminated on both surfaces thereof, and press-molded to obtain a 1.6 mm-thick laminate. Residual air bubbles were observed in the glass fibers in the laminate, and a good plate could not be obtained.

The laminates obtained in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, 4 were cut into 6 cm squares and allowed to absorb moisture for 1 hour to 4 hours in steam at 130 ° C. It was measured. Further, the moisture-absorbed laminate was immersed in molten solder at 260 ° C., and the laminate was observed for blistering and the like. Moisture absorption rate and solder heat resistance after moisture absorption [Effect of the Invention] The inorganic fiber woven fabric according to the present invention is an inorganic fiber woven fabric having a specific structure and a specific air permeability of 1.5 × 10 ^-2 (cm ³ / cm ² · sec) or less. Even when placed in a moisture-absorbing environment, a laminate made of is significantly less likely to absorb moisture than conventional products, and can improve heat resistance and electrical properties after moisture absorption.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI // H05K 1/03 610 H05K 1/03 610T

Claims (1)

(57) [Claims] An inorganic fiber woven fabric having a thickness of 0.25 mm or less composed of inorganic fibers having a filament diameter of 3 to 11 μm is treated with a pressure wave of a fluid or a high-pressure columnar flow after greige or heat cleaning to form a woven fabric. After the yarn is defibrated, the defibrated woven fabric is subjected to pressure melting treatment to prepare a heat-cleaning woven fabric having a specific air permeability X of 1.5 × 10 ^-2 cm ³ / cm ² · sec or less. Of producing an inorganic fiber fabric for a laminated board. However, the specific air permeability X is represented by the following equation. X = A · M A: Permeability per cm ² (unit: cm ³ / cm ² · sec) determined by JIS-L 1096 “Permeability test A method” M: Volume in glass bulk equivalent per 1 cm ^{2 of} woven fabric (Cm) M = w / ρ ρ: Specific gravity of the inorganic material (unit: g / cm ³ ) w: Weight per 1 cm ^{2 of the} woven fabric (unit: g / cm ² )