JPH05170483A - Glass fiber for fiber reinforced plastics and fiber reinforced plastic product - Google Patents

Abstract

PURPOSE:To provide glass fibers for fiber reinforced plastics having a low dielectric loss and high strength and a fiber reinforced plastic product. CONSTITUTION:The objective glass fibers for fiber reinforced plastics are silica glass fibers having <=1,000wt.ppm OH content and >=50kg/mm<2> tensile strength and contg. >=95wt.% SiO2. The objective fiber reinforced plastic product contains the glass fibers.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to silica glass fibers for fiber reinforced plastics and reinforced plastic products using such fibers.

[0002]

2. Description of the Related Art Fiber reinforced plastics in which glass fibers are impregnated with an organic polymer have hitherto been used in a wide variety of application fields. As one of its applications, fiber reinforced plastics are being used in recent years as printed circuit boards for high frequency circuits and as materials for radar domes (radomes). However, when used for such applications, conventional fiber reinforced plastics have dielectric properties in the high frequency band. There is a problem that the loss is large because the loss is large.

The causes are roughly classified into two. Ie
(1) Dielectric loss of organic polymer, (2) Dielectric loss of reinforcing glass fiber. The dielectric loss of conventional glass fibers basically depends on the glass composition, and it is known that silica glass generally exhibits good characteristics. As a method for producing silica glass, a reach-out method, a melting method, and a sol-gel method are known in addition to the method of producing from glass as disclosed in JP-A-3-119240. But,
These silica glasses are not always sufficiently satisfactory for low dielectric loss, and their improvement has been strongly desired.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and silica glass fiber for fiber reinforced plastics, high frequency circuit printed circuit board and radar dome (radome) having low dielectric loss using the same as the reinforcing fiber.
It is to provide materials for use.

[0005]

The present invention has been made to solve the above-mentioned problems, and has an OH content of 10 by weight.
The tensile strength is 50 ppm or less and the tensile strength is 50 kg / mm ²
It is intended to provide a silica glass fiber for a fiber reinforced plastic, which is characterized by comprising the above silica glass fiber.

The present invention also has an OH content of 1000 p.
pm or less, tensile strength is 50 kg / mm ² or more,
At least one of Al ₂ O ₃ , B ₂ O ₃ and TiO ₂ is contained in a total amount of 0.05 to 5.0% by weight, and SiO ₂ is 95% by weight or more, preferably 99% by weight. The present invention provides a glass fiber for a fiber reinforced plastic, which is characterized by comprising the silica glass fiber contained above (the content is hereinafter referred to as a weight ratio).

Further, the present invention is manufactured by the sol-gel method and has an OH content of 1000 ppm or less and a tensile strength of 50.
kg / mm ² or more, carbon content of 10 ppm or less, total amount of alkali metal and alkaline earth metal is 10 pp
m or less, a halogen element content of 100 ppm or less, and SiO ₂ of 95% or more, preferably 99% or more, and comprising a silica glass fiber having a tensile strength in the range of 60 to 150 kg / mm ^2. A glass fiber for plastics is provided.

Further, the present invention is manufactured by the sol-gel method and has an OH content of 1000 ppm or less and a tensile strength of 50.
kg / mm ² or more, and the total amount of at least one of Al ₂ O ₃ , B ₂ O ₃ and TiO ₂ is 0.05.
Up to 5.0 wt%, with a carbon content of 10 ppm
Below, the total amount of alkali metal and alkaline earth metal is 10p
pm or less, a halogen element content of 100 ppm or less, and SiO ₂ of 95% or more, preferably 99% or more,
The present invention provides a glass fiber for a fiber reinforced plastic, which is made of silica glass fiber having a tensile strength of 60 to 150 kg / mm ² .

The present invention also uses SiO as the reinforcing fiber.
₂ Content of 95% or more, OH content is 1000 ppm or less, and the tensile loss at a frequency of 10 GHz using glass fibers for fiber reinforced plastics made of silica glass fibers having a tensile strength of 50 kg / mm ² or more. 5 x 1
The present invention provides a printed circuit board made of fiber reinforced plastic, which is characterized in that it is 0 ^-4 or less.

The present invention also uses SiO as the reinforcing fiber.
₂ Content of 95% or more, OH content is 1000 ppm or less, and the tensile loss at a frequency of 10 GHz using glass fibers for fiber reinforced plastics made of silica glass fibers having a tensile strength of 50 kg / mm ² or more. 5 x 1
The present invention provides a structural material for a radome made of fiber reinforced plastic, which is characterized in that it is 0 ^-4 or less.

In order to obtain the desired low dielectric loss characteristics in the present invention, the content of SiO ₂ is 95% by weight or more,
It is preferably 99% or more. Further, the silica glass fiber in the present invention can be produced by, for example, the sol-gel method.

The inventors of the present invention have conducted extensive research into reducing the dielectric loss of silica glass fiber in order to reduce the electrical characteristics of the printed circuit board, particularly the dielectric loss. As a result, as shown in FIG. 1, it was found that the amount of water contained in silica glass has a great influence on the dielectric loss.
The silica glass fiber for plastic reinforcement such as printed circuit boards and radome substrates has a water content of 1000 pp.
I found that it should be kept below m. The water content referred to here is the infrared spectroscopic analyzer (Nicolet 20
Using the DXC) compared with the values of the height of the ratio of the water content known samples of the silanol peak in the measurement chart (3660cm ^-1) and siloxane bonds peak (1860 cm ^-1) which diffuse reflection IR method It is calculated by

In the present invention, the amount of water contained in the silica glass fiber is preferably 1000 ppm or less, and when the amount of water is higher than this, the electrical characteristics at high frequencies are deteriorated, which is not preferable. The fiber strength is 50
It is preferably not less than kg / mm ² , and if the strength is lower than this, the properties as a reinforcing material are inferior, which is not preferable.
Particularly preferably, it is 60 to 150 kg / mm ² . If the strength is higher than this, the workability at the time of producing the printed circuit board is deteriorated, which is not preferable.

Further, in the present invention, it is advantageous that the silica glass fiber contains at least one of Al ₂ O ₃ , B ₂ O ₃ and TiO _{2 in} a total amount of 0.05 to 5.0%. It is preferable for improving the characteristics. Further, particularly, when the total amount is 0.05 to 5.0%, Al ₂ O ₃ , B ₂ O ₃ ,
TiO ₂ contains at least one kind, and when the content is Al ₂ O ₃ , it is 0.05 to 0.5%, when it is B ₂ O ₃ , it is 0.5 to 5.0%, and TiO ₂ In the case of 0.0
It is preferably in the range of 5 to 0.5%. If the content is less than the lower limit of these ranges, the contribution to the improvement of strength properties is poor, and if the content exceeds the upper limits of these ranges, other properties are adversely affected, which is not preferable.

Further, in the present invention, the carbon content in the silica glass fiber is preferably 10 ppm or less, and when more carbon is contained, the electrical characteristics are deteriorated, which is preferable. Absent. The total amount of alkali metal and alkaline earth metal is preferably 10 ppm or less, and when more alkali and alkaline earth metal are contained, the electrical characteristics deteriorate, which is not preferable. Further, the halogen content is preferably 100 ppm or less, and when the halogen content is more than 100 ppm, the electrical characteristics are deteriorated like carbon, alkali metal and alkaline earth metal, which is not preferable.

The method for producing the silica glass fiber is not particularly limited as long as the above items are satisfied. For example, a gel fiber spun from a gel solution obtained by hydrolyzing and polycondensing a silicon alkoxide solution is used. It can be prepared by a method of heating to a transparent vitrification temperature to form vitrified silica glass fibers. The silicon alkoxide solution is a solution of alkoxide dissolved in an organic solvent. The type of this alkoxide is not particularly limited.

When the final fiber is composed of a plurality of metal oxides, the main component silicon is alkoxide,
Compounds other than alkoxides such as chlorides, nitrates, chelates, and complex salts can be used as the trace metals. Further, to the alkoxide solution, water, an acid such as nitric acid which serves as a catalyst for hydrolysis, an alkali such as ammonia, and a viscosity modifier for forming a fibrous gel can be added. As this regulator, polyethylene glycol, cellulose acetate,
Examples are ethylene oxide, polyvinyl alcohol, hydroxypropyl cellulose, ethylene glycol, propylene glycol, and hexylene glycol.

On the other hand, examples of the organic solvent for the alkoxide solution include methyl alcohol, ethyl alcohol, butyl alcohol, xylene, toluene, ethyl acetate, acetone, methylene chloride, and 1,1,1-trichloroethane. In the present invention, the alkoxide solution in the course of the hydrolysis reaction is extruded with a constant viscosity by the hydrolysis reaction and the viscosity modifier to form gel fibers. If the viscosity is too low, it is difficult for the gel extruded from the nozzle to maintain the fibrous state, while if it is too high, a high pressure is required to extrude from the nozzle, which lowers the workability, which is not preferable. Such viscosity is 1-100
The range of 0 poise is desirable, and the range of 5 to 700 poise is more preferable. The pressure at which the solution is pushed out from the nozzle may be determined so that the fibrous gel is stably formed, and is usually in the range of 0.5 to 100 kg / cm ² .

In the present invention, the gel fiber formed may be fired immediately after the formation, but it is preferable that the gel fiber is fired after the hydrolysis and condensation reactions are promoted in order to increase the strength. However, if the reaction proceeds excessively, it becomes difficult to burn the organic components in the gel fiber, and carbon easily remains in the silica glass fiber formed by firing, so firing is performed within 10 days after the gel fiber is formed. It is preferable to carry out.

In the present invention, it is necessary to remove the organic component present in the gel fiber by burning, but it is preferable to burn the organic component at 700 ° C. or lower.
More preferably, the temperature is up to 600 ° C. If the temperature is 400 ° C. or lower, the burning of the organic component is insufficient, and if the temperature is 700 ° C. or higher, the silica glass fiber after firing is colored due to carbonization of the organic component, which is not preferable. The gas introduced to assist the combustion of such organic components is not particularly limited as long as it contains oxygen and does not adversely affect the gel fiber.

The gel fiber is vitrified at a temperature of 800 ° C. or higher after burning an organic component at 600 ° C. or lower. During such vitrification, silanol is effectively dehydrated at a temperature of 900 ° C. or more, so that the residence time at 900 ° C. or more is preferably 1 minute or more. Further, the higher the maximum firing temperature is, the more the water content can be reduced, but when the temperature is 1200 ° C. or higher, the yarn strength is rapidly reduced. Therefore, the maximum firing temperature is preferably 1000 to 1200 ° C.

Further, in the present invention, it is preferable to apply a tension when firing the gel fiber in order to obtain a fiber having a high tensile strength, and the applied tension is preferably 10 to 120 kg / mm ² . If the applied tension is made higher than this, yarn breakage will occur, which is not preferable. The glass fiber obtained through the above steps has a water content in the silica glass fiber of 1000 ppm or less and a carbon content of 10
It will be below ppm.

Further, since the silica glass fiber produced by the present invention can use a high-purity synthetic material as a glass forming material, it is possible to use alkali metal elements such as sodium and potassium and alkaline earth metals such as calcium and magnesium. The total purity is 10 ppm or less, and halogen elements such as chlorine are 10 ppm or less, which is extremely high purity. Therefore, the printed circuit board and the radome board using the silica glass fiber have a dielectric loss of 5 × at a frequency of 10 GHz.
It has excellent electrical characteristics of 10 −4 or less. In addition, the tensile strength of the fiber is excellent at 60 to 150 kg / mm ² .

Hereinafter, the details of the present invention will be further described with reference to examples, but it goes without saying that the content of the present invention is not limited to these examples.

[0025]

【Example】

[Example 1] A solution containing 640 g of ethyl silicate 40 (product of Nippon Corcoat), 250 g of ethanol, and 56 g of water was hydrolyzed using nitric acid as a catalyst. This solution is S
A spinning solution concentrated so that the content of iO ₂ was 46% by weight was prepared, and gel fibers were formed by a spinning device.
This is fired in an air atmosphere containing oxygen sufficient for combustion under a tension of 70 g / mm ² at an average heating rate of 700 ° C./min from room temperature to 1100 ° C. and a residence time of 2 minutes at 900 ° C. or more. Then, colorless and transparent glass fiber was obtained. The obtained glass fiber had a water content of 500 ppm and a monofilament strength of 90 kg / mm ² . When a fiber-reinforced PTFE resin printed circuit board was created using a treated cloth obtained by subjecting a woven cloth to a woven cloth through a required processing step such as a twisting step and polytetrafluoroethylene (PTFE) resin, in a 10 GHz band Dielectric loss (t
an δ) was 3 × 10 ^-4 .

Example 2 A solution containing 640 g of ethyl silicate 40 (product of Nippon Corcoat Co., Ltd.), 250 g of ethanol and 56 g of water was hydrolyzed using nitric acid as a catalyst, and the content of SiO ₂ was 46% by weight. So concentrated. A mixed solution of aluminum isopropoxide, titanium butoxide, acetylacetone, formic acid and methanol was added to this solution at an Al ₂ O ₃ concentration of 0.2% by weight and TiO 2.
A spinning solution added to have a ₂ concentration of 0.17% by weight was prepared and gel fibers were formed by a spinning device. This was fired under a tension of 100 g / mm ^{2 in} an air atmosphere containing sufficient oxygen for combustion at an average temperature rising rate of 750 ° C. from room temperature to 1100 ° C. and a residence time of 1.5 minutes at 900 ° C. or higher. A colorless and transparent glass fiber was obtained. The obtained glass fiber has a water content of 600 ppm and a monofilament strength of 120 k.
It was g / mm ² . In addition, the dielectric loss (tan) of the fiber-reinforced PTFE printed circuit board prepared by using the cloth made from this fiber and the PTFE resin in the same manner as in Example 1.
δ) was 3.5 × 10 ⁻⁴ in the 10 GHz band.

Example 3 A solution containing 640 g of ethyl silicate 40 (product of Nippon Corcoat Co., Ltd.), 250 g of ethanol and 56 g of water was hydrolyzed using nitric acid as a catalyst, and the content of SiO ₂ was 46% by weight. So concentrated. To this solution, triethoxyboron was added to the final fiber B ₂ O ₃
A spinning solution added to have a concentration of 3% was prepared, and gel fibers were formed by a spinning device. 80g /
Under an air atmosphere containing a sufficient amount of oxygen for combustion under a tension of mm ^2, an average temperature rising rate of 700 ° C. from room temperature to 1050 ° C.
It was fired at a residence time of 2 minutes at a temperature of 900 ° C. or higher for min to obtain colorless and transparent glass fibers. The obtained glass fiber has a water content of 5
00ppm, monofilament strength 100kg / mm ²
Met. Further, the dielectric loss (tan δ) of the fiber-reinforced PTFE printed circuit board produced by using the cloth made from this fiber and the PTFE resin in the same manner as in Example 1 is 10G.
It was 4 × 10 ⁻⁴ in the Hz band.

[0028]

According to the present invention, the OH content is 1000
Silica glass fibers having a tensile strength of 50 kg / mm ² or more can be easily obtained. Further, according to the present invention, a glass fiber reinforced plastic product manufactured by using such silica glass fiber as a reinforcing fiber is used.
The dielectric loss (tan δ) in the GHz band is 5 × 10 ⁻⁴ or less, which is a good characteristic.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of water in silica glass and the dielectric loss at 10 GHz.

Front page continued (72) Inventor Naoki Taneda 1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa Asahi Glass Co., Ltd. Central Research Laboratory

Claims (14)

[Claims] 1. A glass fiber for fiber reinforced plastics, which comprises silica glass fiber having an OH content of 1000 ppm or less by weight and a tensile strength of 50 kg / mm ² or more. 2. Silica glass fibers containing 95% by weight of SiO _2.
The glass fiber for fiber-reinforced plastics according to claim 1, characterized by containing the above. 3. Silica glass fibers containing 99% by weight of SiO _2.
The glass fiber for fiber-reinforced plastics according to claim 1, characterized by containing the above. 4. A silica glass fiber comprising Al ₂ O ₃ and B ₂ O.
_The glass fiber for fiber-reinforced plastics according to claim 2 or 3, wherein the total amount of at least one of ₃ and TiO ₂ is contained in a range of 0.05 to 5.0% by weight. 5. Silica glass fibers are produced by a sol-gel method, have a carbon content of 10 ppm or less by weight, a total amount of alkali metals and alkaline earth metals of 10 ppm or less, a halogen element content of 100 ppm or less, and a tensile strength. Strength 6
The glass fiber for a fiber reinforced plastic according to claim 2 or 3, wherein the glass fiber is in a range of 0 to 150 kg / mm ² . 6. A silica glass fiber is produced by a sol-gel method and contains at least one of Al ₂ O ₃ , B ₂ O ₃ and TiO _{2 in} a total amount of 0.05 to 5.0% by weight. It is characterized in that the carbon content is 10 ppm or less by weight, the total amount of alkali metal and alkaline earth metal is 10 ppm or less, the halogen element content is 100 ppm or less, and the tensile strength is in the range of 60 to 150 kg / mm ^2. The glass fiber for a fiber reinforced plastic according to claim 2 or 3. 7. A fiber reinforced plastic made of silica glass fiber having a SiO ₂ content of 95% or more by weight, an OH content of 1000 ppm or less and a tensile strength of 50 kg / mm ² or more as a reinforcing fiber. A printed circuit board made of glass fiber, which has a dielectric loss at a frequency of 10 GHz of 5 × 10 ⁻⁴ or less. 8. A fiber reinforced plastic comprising silica glass fiber having a SiO ₂ content of 95% or more by weight, an OH content of 1000 ppm or less and a tensile strength of 50 kg / mm ² or more as a reinforcing fiber. A structural material for a radome made of fiber reinforced plastic, which uses glass fiber and has a dielectric loss of 5 × 10 ⁻⁴ or less at a frequency of 10 GHz. 9. The printed circuit board made of fiber reinforced plastic according to claim 7, wherein the glass fiber for fiber reinforced plastic according to claim 4 is used as the reinforcing fiber. 10. The fiber-reinforced plastic printed circuit board according to claim 7, wherein the glass fiber for fiber-reinforced plastic according to claim 5 is used as the reinforcing fiber. 11. The fiber-reinforced plastic printed circuit board according to claim 7, wherein the glass fiber for fiber-reinforced plastic according to claim 6 is used as the reinforcing fiber. 12. The fiber-reinforced plastic radome structural material according to claim 8, wherein the glass fiber for fiber-reinforced plastic according to claim 4 is used as the reinforcing fiber. 13. The fiber-reinforced plastic radome structural material according to claim 8, wherein the glass fiber for fiber-reinforced plastic according to claim 5 is used as the reinforcing fiber. 14. The fiber-reinforced plastic radome structural material according to claim 8, wherein the glass fiber for fiber-reinforced plastic according to claim 6 is used as the reinforcing fiber.