Glass composition for glass fibers, glass fibers, glass fiber fabric, and glass fiber-reinforced resin composition

Abstract

The invention provides a glass composition for glass fibers. A molten glass having both a high elastic modulus and a low linear expansion coefficient and having excellent composition uniformity and clarity can be obtained. This glass composition for glass fibers contains, relative to the total amount, 42.00 to 70.00 mass% of S i O2, 10.00 to 30.00 mass% of Al 2O3, 0.00 to 8.00 mass% of MgO, 0.00 to 5.00 mass% of CaO, 2.00 to 25.00 mass% of ZnO, 0.00 to 5.00 mass% of T iO2, 2.00 to 17.30 mass% of P2O5, and 0.01 to 2.00 mass% of MxOy (at least one oxide selected from the group consisting of Fe2O3, SnO2, CeO2, MnO2, Sb2O3, and As2O3) in total. The content Z of the ZnO, the content P of the P2O5, and the content M of the MxOy satisfy the following formula (1). (1) 0.088 < = (Z / P) * M1 / 2 < = 3.554.

Description

Technical Field

[0001] The present invention relates to a glass composition for glass fibers, glass fibers, glass fiber fabrics, and glass fiber reinforced resin compositions. Background Art

[0002] Conventionally, glass fibers have been widely used to improve the strength of resin compositions.

[0003] In recent years, with the miniaturization and light weight of electronic devices, resin compositions such as printed wiring boards used in these electronic devices are required to have high rigidity and excellent dimensional stability. Therefore, glass fibers used to reinforce the above resin compositions are also required to have both a high elastic modulus and a low coefficient of linear expansion.

[0004] In order to achieve both a high elastic modulus and a low coefficient of linear expansion of glass fibers, the present applicant has applied for a patent for a glass composition for glass fibers containing ZnO and P2O5 (Japanese Patent Application 2023-029848, PCT / JP2023 / 014110). Summary of the Invention

[0005] Problems to be Solved by the Invention

[0006] However, the glass fibers obtained from the glass composition for glass fibers described in Japanese Patent Application 2023-029848, PCT / JP2023 / 014110 have problems in that the elastic modulus and the coefficient of linear expansion deviate.

[0007] The inventors of the present invention have conducted an in-depth study on the cause of the above problems and found the following: When melting the glass composition for glass fibers to obtain molten glass, ZnO and P2O5 are not easily dissolved in the initial stage of melting. Therefore, due to insufficient stirring during melting, the composition of the molten glass deviates, and in the glass composition for glass fibers containing both ZnO and P2O5, the deviation of the composition of the molten glass is significantly generated. As a result, the elastic modulus and the coefficient of linear expansion of the glass fibers obtained from the molten glass deviate.

[0008] It should be noted that the deviation in the composition of the molten glass in this application is a kind of deviation that gradually generates a composition difference throughout the whole within the molten glass, which is different from problems such as striae and phase separation where heterogeneous glass regions or heterogeneous glass phases with different compositions from the surrounding glass are locally generated. It should be noted that striae refer to rib-shaped regions with a glass composition different from that of the surrounding glass and with a size of several millimeters or less, and phase separation refers to a phase separation phenomenon in which a single-phase molten glass forms glass phases with different compositions of several micrometers or less due to reasons such as heating. The composition difference between such heterogeneous glass regions or different glass phases and the surrounding glass is relatively large, resulting in a refractive index difference, so it can be observed with the naked eye or by optical methods. However, the glass composition for glass fibers described in Japanese Patent Application 2023-029848, PCT / JP2023 / 014110 does not have problems such as striae and phase separation that can be detected with the naked eye or the like.

[0009] That is, the deviation in the composition of the molten glass in this application is the result of in-depth research by the inventors of the present invention to eliminate the above problems, and is also the result first discovered by observing using the method described below.

[0010] Among them, as a method of stirring the molten glass during the melting of the molten glass, it is considered to add components that generate gas during melting, such as Fe2O3, SnO2, CeO2, MnO2, Sb2O3, and As2O3, to the glass composition for glass fibers. When the above components are added to the above glass composition for glass fibers, the components will generate gas during the melting of the above molten glass, and the generated gas will move upward, thereby expecting to obtain the effect of stirring the molten glass.

[0011] On the other hand, when the above components generate gas during the melting of the molten glass, the clarification of the molten glass decreases, and the glass filaments constituting the glass fibers will contain bubbles (hollow parts). When a glass fiber-reinforced resin composition using the glass fibers is made into a printed wiring board, there may be problems that cause a decrease in the insulation reliability of the printed wiring board.

[0012] Therefore, an object of the present invention is to eliminate the above problems and provide a glass composition for glass fibers that can obtain glass fibers with both high elastic modulus and low linear expansion coefficient and can obtain molten glass with excellent compositional uniformity and clarification.

[0013] Means for Solving the Problem

[0014] The inventors of the present invention repeatedly conducted research to achieve the above object, and as a result, it was found that by adjusting the content ratios of ZnO, P2O5, and MxOy (at least one or more oxides selected from the group consisting of Fe2O3, SnO2, CeO2, MnO2, Sb2O3, and As2O3) in a glass composition for glass fibers having a specific composition, glass fibers having both a high elastic modulus and a low coefficient of linear expansion can be obtained. Moreover, the compositional uniformity of the molten glass can be achieved, and the amount of bubbles contained in the molten glass can be reduced, improving the clarification of the molten glass, and thus the present invention was completed.

[0015] Therefore, the glass composition for glass fibers of the present invention is characterized in that it contains SiO2 in the range of 42.00 to 70.00% by mass, Al2O3 in the range of 10.00 to 30.00% by mass, MgO in the range of 0.00 to 8.00% by mass, CaO in the range of 0.00 to 5.00% by mass, ZnO in the range of 2.00 to 25.00% by mass, TiO2 in the range of 0.00 to 5.00% by mass, P2O5 in the range of 2.00 to 17.30% by mass, and MxOy (at least one or more oxides selected from the group consisting of Fe2O3, SnO2, CeO2, MnO2, Sb2O3, and As2O3) in the range of 0.01 to 2.00% by mass in total, and the content ratio Z of ZnO, the content ratio P of P2O5, and the content ratio M of MxOy satisfy the following formula (1):

[0016] 0.088 ≤ (Z / P) × M 1 / 2 ≤ 3.554…(1).

[0017] The glass composition for glass fibers of the present invention can obtain glass fibers having a high elastic modulus and a low coefficient of linear expansion by containing SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy in the above ranges with respect to the total amount.

[0018] Among them, that the glass fiber has a high elastic modulus means that the elastic modulus of the glass fiber measured by the following elastic modulus measurement method is 70.0 GPa or more; that the glass fiber has a low coefficient of linear expansion means that the coefficient of linear expansion of the glass fiber calculated by the following coefficient of linear expansion measurement method is 3.0 ppm / K or less.

[0019] 〔Elastic modulus measurement method〕

[0020] First, put the glass batch adjusted to the composition of the glass composition for glass fibers into a platinum crucible with a diameter of 80 mm, heat it at a temperature of 1650 °C for 6 hours to melt it, and then take it out from the platinum crucible to obtain a homogeneous glass block or glass chips. Next, anneal the obtained glass block or glass chips at a temperature of 750 °C for 8 hours to obtain a test piece. Then, use a cutting machine, such as a diamond tool and a grinding machine, to process the above test piece into a test piece for measuring the elastic modulus with dimensions of 50 mm × 50 mm × 5 mm, and use this test piece for measuring the elastic modulus to measure the elastic modulus by the ultrasonic pulse method in accordance with JIS R 1602∶1995.

[0021] 〔Method for measuring coefficient of linear expansion〕

[0022] First, use a cutting machine, such as a diamond cutter and a grinding machine, to process the test piece prepared in the same manner as in the measurement of the above elastic modulus into a test piece for measuring the coefficient of linear expansion with dimensions of 4 mm × 4 mm × 20 mm. Next, heat the obtained test piece for measuring the coefficient of linear expansion at a heating rate of 10 °C / minute, and in the temperature range of 50 °C to 200 °C, use a thermal expansion rate measuring device (manufactured by NETZSCH Corporation, product name: DIL402) to measure the elongation amount, and calculate the coefficient of linear expansion based on this elongation amount.

[0023] In addition, the glass composition for glass fibers according to the present invention contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy in the above content ranges relative to the total amount, and the content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy formula (1). Thus, when MxOy generates gas in the molten glass, the generated gas will entrain the minute bubbles present in the molten glass to form large bubbles, and these large bubbles will float upward in the molten glass and easily separate from the molten glass. As a result, the clarity of the molten glass can be improved, and the bubbles (hollow parts) contained in the glass fibers obtained from the glass composition for glass fibers can be reduced.

[0024] Among them, a high clarity of the molten glass means that the number of bubbles per g of the glass block measured by the following clarity evaluation method is 150 or more and less than 1000.

[0025] 〔Clarity evaluation method〕

[0026] First, put the glass batch adjusted to the composition of the glass composition for glass fiber into a platinum crucible with a diameter of 80 mm, melt it at a temperature of 1600 °C for 3 hours, and then take it out from the platinum crucible to obtain a glass block. Next, heat the obtained glass block at a temperature of 750 °C for 2 hours, and then cool it to room temperature over 8 hours for annealing to obtain a test piece. Next, use a cutting machine, such as a diamond tool, to cut out a 10 mm × 15 mm size from the center of the obtained test piece, and grind its surface with #2000 abrasive paper. Next, use an optical microscope to measure the number of air bubbles contained in the test piece whose surface has been ground.

[0027] In addition, for the glass composition for glass fiber according to the present invention, when the large air bubbles float to the upper part of the molten glass, by stirring the molten glass, ZnO and P2O5 are easily dissolved, and the compositional uniformity of the molten glass can be achieved.

[0028] Among them, the compositional uniformity of the molten glass means that the compositional uniformity calculated by the following evaluation method of compositional uniformity is 10.0% or less.

[0029] 〔Evaluation method of compositional uniformity〕

[0030] First, use a cutting machine, such as a diamond tool, to cut out a test piece with an upper surface and a bottom surface of 10 mm × 15 mm in size from the center of the test piece obtained in the same manner as in the above evaluation method of clarity. Grind the side surface with #2000 abrasive paper. Next, perform compositional analysis on the side surface of the above test piece whose surface has been ground by using EDS (energy dispersive spectroscopy) to evaluate the compositional difference between the upper surface region and the bottom surface region. Specifically, use a field emission scanning electron microscope (FE-SEM, manufactured by JEOL Ltd., model: JSM-IT800) and an energy dispersive spectroscopy device (manufactured by JEOL Ltd., model: EDS30mm 2 detector), and for an arbitrary 100 μm in the region at a height of 1 mm from each of the upper surface and the bottom surface 2Under the above-mentioned vision, regional measurement is carried out, and the content (%) in terms of oxides of each element contained in the glass composition for glass fibers is measured. It should be noted that the content in terms of oxides of the above-mentioned elements is measured for three different regions of the upper surface region and the bottom surface region respectively, and the average value of the measurement results of the three regions is used as the content in terms of oxides of each element. For each element, the absolute value of the difference between the content in terms of oxides of the upper surface region and the content in terms of oxides of the bottom surface region is calculated, and the calculation is carried out for all the detected elements. The value obtained by adding up the absolute values of the differences in the above-mentioned contents of all elements is used as the compositional uniformity. It should be noted that the smaller the value of the above-mentioned compositional uniformity, the smaller the deviation in the composition of the molten glass (the more excellent the uniformity).

[0031] In addition, preferably, the glass composition for glass fibers of the present invention contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy in the above ranges respectively with respect to the total amount, and the content Z of ZnO, the content P of P2O5, and the content M of MxOy satisfy the following formula (2).

[0032] 0.183 ≤ (Z / P) × M 1 / 2 ≤ 1.775…(2)

[0033] The glass composition for glass fibers of the present invention contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy in the above ranges respectively with respect to the total amount, and the content Z of ZnO, the content P of P2O5, and the content M of MxOy satisfy formula (2). Thereby, glass fibers having a high elastic modulus and a low linear expansion coefficient can be obtained, the composition of the above-mentioned molten glass can be made more uniform, and the clarification of the molten glass can be further improved.

[0034] Among them, further improving the clarification of the molten glass means that the number of bubbles per g of the glass block measured by the above-mentioned evaluation method of clarification is less than 150. In addition, the more uniform composition of the molten glass means that the compositional uniformity calculated by the above-mentioned evaluation method of compositional uniformity is 8.0% or less.

[0035] Further, preferably, the glass composition for glass fibers of the present invention contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy within the above ranges respectively with respect to the total amount. When the content rate Z of the above ZnO, the content rate P of the above P2O5, and the content rate M of the above MxOy satisfy formula (2), it further contains Fe2O3 in the range of 0.01 to 2.00% by mass and SnO2 in the range of 0.01 to 2.00% by mass. The content rate F of the above Fe2O3 and the content rate S of the above SnO2 satisfy the following formula (3).

[0036] 0.06 ≤ S / F ≤ 40.75 ··· (3)

[0037] The glass composition for glass fibers of the present invention contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy within the above ranges respectively with respect to the total amount. When the content rate Z of the above ZnO, the content rate P of the above P2O5, and the content rate M of the above MxOy satisfy formula (2), it also contains Fe2O3 in the range of 0.01 to 2.00% by mass and SnO2 in the range of 0.01 to 2.00% by mass. The content rate F of the above Fe2O3 and the content rate S of the above SnO2 satisfy formula (3). Thereby, glass fibers having a high elastic modulus and a low linear expansion coefficient can be obtained, the clarification of the above molten glass can be further improved, and further uniformity of the composition of the molten glass can be achieved.

[0038] Among them, the composition of the molten glass being more uniform means that the composition uniformity calculated by the aforementioned evaluation method of composition uniformity is 5.0% or less.

[0039] Further, preferably, the glass composition for glass fibers of the present invention contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy within the above ranges respectively with respect to the total amount. The content rate Z of the above ZnO, the content rate P of the above P2O5, and the content rate M of the above MxOy satisfy the following formula (4).

[0040] 0.183 ≤ (Z / P) × M 1 / 2 ≤ 0.582 … (4)

[0041] The glass composition for glass fibers of the present invention contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy within the above ranges respectively with respect to the total amount. The content rate Z of the above ZnO, the content rate P of the above P2O5, and the content rate M of the above MxOy satisfy formula (4). Thereby, glass fibers having a high elastic modulus and a low linear expansion coefficient can be obtained, the clarification of the above molten glass can be further improved, and moreover, further uniformity of the composition of the molten glass can be achieved.

[0042] Among them, the more uniform composition of the molten glass means that the composition uniformity calculated by the aforementioned evaluation method of composition uniformity is 3.0% or less.

[0043] The glass fiber of the present invention is characterized by including glass filaments formed from any one of the above glass compositions for glass fibers. In addition, the glass fiber fabric or the glass fiber reinforced resin composition of the present invention is characterized by including the glass fiber of the present invention. Detailed Description of Embodiments

[0044] Next, the embodiments of the present invention will be further described in detail.

[0045] The glass composition for glass fibers of the first embodiment in the present embodiment contains SiO2 in the range of 42.00 to 70.00% by mass, Al2O3 in the range of 10.00 to 30.00% by mass, MgO in the range of 0.00 to 8.00% by mass, CaO in the range of 0.00 to 5.00% by mass, ZnO in the range of 2.00 to 25.00% by mass, TiO2 in the range of 0.00 to 5.00% by mass, P2O5 in the range of 2.00 to 17.30% by mass, and MxOy (at least one or more oxides selected from the group consisting of Fe2O3, SnO2, CeO2, MnO2, Sb2O3, and As2O3) in the range of 0.01 to 2.00% by mass in total. The content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy the following formula (1), and preferably satisfy the following formula (2).

[0046] 0.088 ≤ (Z / P) × M 1 / 2 ≤ 3.554…(1)

[0047] 0.183 ≤ (Z / P) × M 1 / 2 ≤ 1.775…(2)

[0048] According to the glass composition for glass fibers of the first embodiment of the present embodiment, by making the glass composition for glass fibers contain SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy in the above ranges respectively in total, glass fibers having a high elastic modulus and a low linear expansion coefficient can be obtained.

[0049] In addition, the glass composition for glass fibers according to the first embodiment of the present embodiment contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy within the above ranges with respect to the total amount. The content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy formula (1). Thus, when MxOy generates gas in the molten glass, the generated gas entrains the minute bubbles present in the molten glass to form large bubbles, and these large bubbles easily float to the upper part of the molten glass and separate from the molten glass. As a result, the clarification of the molten glass can be improved, and the bubbles (hollow parts) contained in the glass fibers obtained using the glass composition for glass fibers can be reduced. In addition, by stirring the molten glass when the large bubbles float to the upper part of the molten glass, ZnO and P2O5 are easily dissolved, and the compositional uniformity of the molten glass can be achieved.

[0050] It should be noted that in the above molten glass, Fe2O3 mainly generates gas in the temperature range of 1400 to 1500 °C, SnO2 mainly generates gas in the temperature range of 1500 to 1630 °C, CeO2 generates gas in the temperature range of 1100 to 1400 °C, MnO2 generates gas in the temperature range of 1100 to 1400 °C, Sb2O3 generates gas in the temperature range of 1000 to 1300 °C, and As2O3 generates gas in the temperature range of 1300 to 1600 °C.

[0051] Moreover, for the glass composition for glass fibers according to the first embodiment of the present embodiment, by making the content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy formula (2), glass fibers having a high elastic modulus and a low linear expansion coefficient can be obtained, the composition of the molten glass can be made more uniform, and the clarification of the molten glass can be further improved.

[0052] In addition, the glass composition for glass fibers according to the second embodiment of the present embodiment contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy within the above ranges with respect to the total amount. When the content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy formula (2), it contains Fe2O3 in the range of 0.01 to 2.00 mass% and SnO2 in the range of 0.01 to 2.00 mass%. The content rate F of Fe2O3 and the content rate S of SnO2 satisfy the following formula (3).

[0053] 0.06 ≤ S / F ≤ 40.75…(3)

[0054] The glass composition for glass fibers according to the second embodiment of the present embodiment contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, and MxOy within the above ranges respectively with respect to the total amount. When the content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy formula (2), it further contains Fe2O3 in the range of 0.01 to 2.00% by mass and SnO2 in the range of 0.01 to 2.00% by mass. The content rate F of Fe2O3 and the content rate S of SnO2 satisfy formula (3). Thus, glass fibers having a high elastic modulus and a low linear expansion coefficient can be obtained, the clarification of the molten glass can be further improved, and further uniformity of the composition of the molten glass can be achieved.

[0055] Moreover, the glass composition for glass fibers according to the third embodiment of the present embodiment contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy within the above ranges respectively with respect to the total amount. The content rate Z of the above ZnO, the content rate P of the above P2O5, and the content rate M of the above MxOy satisfy the following formula (4).

[0056] 0.183 ≤ (Z / P) × M 1 / 2 ≤ 0.582…(4)

[0057] The glass composition for glass fibers according to the third embodiment of the present embodiment contains SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5, and MxOy within the above ranges respectively with respect to the total amount. The content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy formula (4). Thus, glass fibers having a high elastic modulus and a low linear expansion coefficient can be obtained, the clarification of the molten glass can be further improved, and further uniformity of the composition of the molten glass can be achieved.

[0058] It should be noted that in the glass compositions for glass fibers in each form of the present embodiment, if the value of Z / P becomes larger, there is a tendency for the linear expansion coefficient of the produced glass fibers to become larger; if the value of Z / P becomes smaller, there is a tendency for the elastic modulus of the produced glass fibers to become smaller. On the other hand, if the value of M becomes larger, the amount of gas generated in the molten glass becomes excessive, so there is a tendency for the clarification of the molten glass to deteriorate; if the value of M becomes smaller, an insufficient amount of gas for stirring the molten glass is generated in the molten glass, and there is a tendency for the uniformity and clarification of the molten glass to deteriorate.

[0059] Therefore, it can be considered that (Z / P) × M 1 / 2 represents the balance between the linear expansion coefficient and elastic modulus of the produced glass fibers and the clarification and compositional uniformity of the molten glass.

[0060] In addition, in the glass composition for glass fibers of the second embodiment of the present embodiment, if the value of S / F increases, the effect of stirring the molten glass in the temperature range of 1400 to 1500 °C becomes insufficient, so there is a tendency for the uniformity of the composition of the molten glass to deteriorate. If the value of S / F decreases, the effect of stirring the molten glass in the temperature range of 1500 to 1630 °C and the effect of entraining minute bubbles become insufficient, so there is a tendency for the uniformity and clarification of the composition of the molten glass to deteriorate. Therefore, it can be considered that the value of S / F represents the balance between the stirring effect of the molten glass in the temperature range of 1400 to 1500 °C and the stirring effect of the molten glass in the temperature range of 1500 to 1630 °C.

[0061] The above value of S / F is preferably in the range of 0.20 to 14.00, more preferably in the range of 0.30 to 1.40.

[0062] In the glass composition for glass fibers of each of the above forms in the present embodiment, when the content rate of SiO2 relative to the total amount of the glass composition for glass fibers is less than 42.00% by mass, the operating temperature range becomes narrow, crystallization may precipitate during spinning, and nozzle clogging may occur. In addition, when the content rate of SiO2 exceeds 70.00% by mass, the temperature at 1000 poises becomes high, the meltability deteriorates, and uncompletely melted SiO2 flows into the nozzle as foreign matter, causing breakage during spinning, and thus the productivity deteriorates.

[0063] In the glass composition for glass fibers of each of the above forms in the present embodiment, the content rate of SiO2 relative to the total amount of the glass composition for glass fibers is preferably in the range of 44.00 to 65.00% by mass, more preferably in the range of 45.00 to 62.60% by mass, further preferably in the range of 46.30 to 58.50% by mass, particularly preferably in the range of 47.90 to 55.90% by mass, and especially preferably in the range of 48.90 to 54.90% by mass.

[0064] In the glass composition for glass fibers of each of the above forms in the present embodiment, when the content rate of Al2O3 relative to the total amount of the glass composition for glass fibers is less than 10.00% by mass, the temperature at 1000 poises becomes high, the meltability deteriorates, and the elastic modulus decreases. In addition, when the content rate of Al2O3 exceeds 30.00% by mass, crystallization easily precipitates, and thus the operating temperature range becomes narrow and the spinnability deteriorates.

[0065] In the glass composition for glass fibers in each of the above-described forms of the present embodiment, the content rate of Al2O3 relative to the total amount of the glass composition for glass fibers is preferably in the range of 19.50 to 28.40% by mass, more preferably in the range of 20.50 to 27.80% by mass, further preferably in the range of 22.10 to 27.20% by mass, particularly preferably in the range of 22.60 to 26.40% by mass, and especially preferably in the range of 23.20 to 25.80% by mass.

[0066] In the glass composition for glass fibers in each of the above-described forms of the present embodiment, when the content rate of MgO relative to the total amount of the glass composition for glass fibers exceeds 8.00% by mass, glass fibers having a small coefficient of linear expansion cannot be obtained.

[0067] In the glass composition for glass fibers in each of the above-described forms of the present embodiment, the content rate of MgO relative to the total amount of the glass composition for glass fibers is preferably in the range of 0.00 to 5.90% by mass, more preferably in the range of 0.50 to 5.40% by mass, further preferably in the range of 1.10 to 4.90% by mass, particularly preferably in the range of 1.50 to 4.40% by mass, especially preferably in the range of 1.90 to 2.70% by mass, and extremely preferably in the range of 2.60 to 3.60% by mass.

[0068] In the glass composition for glass fibers in each of the above-described forms of the present embodiment, when the content rate of CaO relative to the total amount of the glass composition for glass fibers exceeds 5.00% by mass, the liquidus temperature becomes high and the spinnability deteriorates.

[0069] In the glass composition for glass fibers in each of the above-described forms of the present embodiment, the content rate of CaO relative to the total amount of the glass composition for glass fibers is preferably in the range of 0.00 to 5.00% by mass, more preferably in the range of 0.00 to 2.50% by mass, further preferably in the range of 0.00 to 0.90% by mass, particularly preferably in the range of 0.00 to 0.40% by mass, especially preferably in the range of not less than 0.00% by mass and less than 0.10% by mass, and extremely preferably in the range of not less than 0.00% by mass and less than 0.05% by mass.

[0070] In the glass composition for glass fibers in each of the above-described forms of the present embodiment, when the content rate of ZnO relative to the total amount of the glass composition for glass fibers is 2.00% by mass or less, the temperature at 1000 poises becomes high and the meltability deteriorates. In addition, when the content rate of ZnO exceeds 25.00% by mass, glass fibers having a small coefficient of linear expansion cannot be obtained.

[0071] In the glass composition for glass fiber of each of the above forms of the present embodiment, the content rate of ZnO relative to the total amount of the glass composition for glass fiber is preferably in the range of 2.50 to 22.00% by mass, more preferably in the range of 3.0 to 18.00% by mass, further preferably in the range of 4.10 to 14.10% by mass, particularly preferably in the range of 5.20 to 11.00% by mass, especially preferably in the range of 6.00 to 10.10% by mass, and most preferably in the range of 6.50 to 9.50% by mass.

[0072] In the glass composition for glass fiber of each of the above forms of the present embodiment, when the content rate of TiO2 relative to the total amount of the glass composition for glass fiber exceeds 5.00% by mass, it is impossible to reduce the melt viscosity while maintaining a low linear expansion coefficient. In addition, the liquidus temperature will rise excessively, and the operating temperature range will become narrow.

[0073] In the glass composition for glass fiber of each of the above forms of the present embodiment, the content rate of TiO2 relative to the total amount of the glass composition for glass fiber is preferably in the range of 0.00 to 2.50% by mass, more preferably in the range of 0.00 to 1.80% by mass, further preferably in the range of 0.00 to 1.20% by mass, and particularly preferably in the range of 0.00 to 0.90% by mass.

[0074] In the glass composition for glass fiber of each of the above forms of the present embodiment, when the content rate of P2O5 relative to the total amount of the glass composition for glass fiber is less than 2.00% by mass, the operating temperature range will become narrow, crystals will precipitate during spinning, and nozzle clogging may occur. In addition, when the content rate of P2O5 exceeds 17.30% by mass, the temperature at 1000 poises becomes high, the meltability deteriorates, and the liquidus temperature becomes high, making it difficult to perform spinning.

[0075] In the glass composition for glass fiber of each of the above forms of the present embodiment, the content rate of P2O5 relative to the total amount of the glass composition for glass fiber is preferably in the range of 3.80 to 17.00% by mass, more preferably in the range of 5.50 to 15.50% by mass, further preferably in the range of 6.50 to 14.90% by mass, particularly preferably in the range of 8.30 to 13.50% by mass, especially preferably in the range of 10.10 to 13.60% by mass, and most preferably in the range of 11.00 to 13.30% by mass.

[0076] The glass composition for glass fiber of each form of the present embodiment contains MxOy in the range of 0.01 to 2.00% by mass relative to the total amount of the glass composition for glass fiber.

[0077] MxOy is one or more oxides selected from the group consisting of Fe2O3, SnO2, CeO2, MnO2, Sb2O3, and As2O3. In order to avoid contamination of equipment due to volatilization during melting, which may lead to inability to use for a long time, MxOy is preferably one or more oxides selected from the group consisting of Fe2O3, SnO2, CeO2, and MnO2, which are oxides of metal elements. From the perspective of production cost, it is more preferably one or more oxides selected from the group consisting of Fe2O3, SnO2, and MnO2, which are not rare earth element oxides. From the perspective of low toxicity of raw materials, it is further preferably one or more oxides selected from the group consisting of Fe2O3 and SnO2.

[0078] In the glass composition for glass fibers of each form of the present embodiment, from the perspective of increasing the stirring effect of molten glass during the long-time temperature rise of molten glass from low temperature to high temperature by increasing the temperature region where gas is generated, the glass composition for glass fibers of each form of the present embodiment preferably contains any two or more oxides selected from the above group, and more preferably contains Fe2O3 and SnO2.

[0079] It should be noted that when the glass composition for glass fibers contains any two or more oxides selected from the above group as MxOy, the content rate M of MxOy represents the total content rate of all oxides contained in MxOy.

[0080] In the glass composition for glass fibers of each form of the present embodiment, when the content rate of MxOy relative to the total amount of the glass composition for glass fibers is less than 0.01% by mass, an amount of gas sufficient to stir the molten glass cannot be generated in the molten glass. In addition, when the content rate of MxOy exceeds 2.00% by mass, the amount of gas generated in the molten glass is excessive, and the clarity of the molten glass deteriorates.

[0081] In the glass composition for glass fibers of each form of the present embodiment, the content rate of MxOy relative to the total amount of the glass composition for glass fibers is preferably in the range of 0.10 to 1.40% by mass, more preferably in the range of 0.15 to 1.20% by mass, further preferably in the range of 0.30 to 0.90% by mass, and particularly preferably in the range of 0.40 to 0.60% by mass.

[0082] When the glass composition for glass fibers in each of the forms of the present embodiment contains Fe2O3, SnO2, CeO2, MnO2, Sb2O3, and As2O3, the content rates relative to the total amount of the glass composition for glass fibers are each independently in the range of 0.01 to 2.00% by mass, preferably in the range of 0.01 to 1.50% by mass, more preferably in the range of 0.10 to 0.90% by mass, further preferably in the range of 0.30 to 0.70% by mass, and particularly preferably in the range of 0.40 to 0.44% by mass.

[0083] When the glass composition for glass fibers in each of the forms of the present embodiment contains Fe2O3 and SnO2, the ratio (S / F) of the content rate S of the above SnO2 to the content rate F of the above Fe2O3 is preferably in the range of 0.06 to 40.75, more preferably in the range of 0.20 to 14.00, further preferably in the range of 0.25 to 4.90, and particularly preferably in the range of 0.30 to 1.40.

[0084] In addition, from the viewpoint of reducing the melting viscosity of the molten glass and thus facilitating long fiberization, the glass composition for glass fibers of the present embodiment may contain ZrO2. When ZrO2 is contained, the content rate of ZrO2 relative to the total amount of the glass composition for glass fibers is, for example, in the range of 3.00% by mass or less, preferably in the range of 1.00% by mass or less, more preferably in the range of 0.60% by mass or less, further preferably in the range of 0.40% by mass or less, particularly preferably in the range of 0.20% by mass or less, especially preferably in the range of 0.10% by mass or less, and extremely preferably in the range of 0.001% by mass or less.

[0085] From the viewpoint of improving spinnability and obtaining glass fibers with a small linear expansion coefficient, the glass composition for glass fibers of the present embodiment may contain B2O3. When B2O3 is contained, the content rate of B2O3 relative to the total amount of the glass composition for glass fibers is, for example, in the range of 10.00% by mass or less, preferably in the range of 7.90% by mass or less, more preferably in the range of 0.50 to 5.90% by mass, further preferably in the range of 1.00 to 4.80% by mass, and particularly preferably in the range of 1.50 to 3.50% by mass.

[0086] In addition, the glass composition for glass fibers of the present embodiment may contain F2 and Cl2. When the glass composition for glass fibers contains F2 and Cl2, the total content ratio of F2 and Cl2 relative to the total amount of the glass composition for glass fibers is, for example, in the range of 3.00% by mass or less, preferably in the range of 1.00% by mass or less, more preferably in the range of 0.40% by mass or less, further preferably in the range of 0.20% by mass or less, particularly preferably in the range of 0.10% by mass or less, and especially preferably in the range of 0.001% by mass or less.

[0087] In addition, the glass composition for glass fibers of the present embodiment may contain Li2O, Na2O, and K2O. When the glass composition for glass fibers contains Li2O, Na2O, and K2O, from the perspective that when the glass composition for glass fibers contains a large amount of Li2O, Na2O, and K2O, the water resistance and linear expansion coefficient of the glass fibers may deteriorate, the total content ratio of Li2O, Na2O, and K2O relative to the total amount of the glass composition for glass fibers is, for example, in the range of 1.00% by mass or less, preferably in the range of 0.50% by mass or less, more preferably in the range of less than 0.10% by mass, further preferably in the range of 0.05% by mass or less, particularly preferably in the range of 0.02% by mass or less, particularly preferably in the range of 0.03% by mass or less, and most preferably in the range of 0.01% by mass or less.

[0088] In addition, in the glass composition for glass fibers of the present embodiment, the ratio (P2O5 / ZnO) of the content rate of P2O5 to the content rate of ZnO is preferably in the range of 0.40 to 5.60. When the ratio (P2O5 / ZnO) of the content rate of P2O5 to the content rate of ZnO is less than 0.40, there is a tendency for the operating temperature range to become smaller or the linear expansion coefficient of the glass fibers formed from the glass composition for glass fibers to become larger. When the ratio of the content rates exceeds 5.60, there is a tendency for the temperature at 1000 poise to become too high. The ratio (P2O5 / ZnO) of the content rate of P2O5 to the content rate of ZnO is more preferably in the range of 0.70 to 4.50, further preferably in the range of 0.80 to 3.70, particularly preferably in the range of 0.90 to 2.80, and extremely preferably in the range of 0.95 to 2.00.

[0089] In the glass composition for glass fibers of the present embodiment, the total content of SiO2, Al2O3, MgO, CaO, ZnO, TiO2, P2O5 and MxOy is, for example, 91.0% by mass or more, preferably 95.0% by mass or more, more preferably 98.0% by mass or more, further preferably 99.0% by mass or more, particularly preferably 99.3% by mass, especially preferably 99.5% by mass or more, extremely preferably 99.7% by mass or more, and most preferably 99.9% by mass or more with respect to the total amount.

[0090] Moreover, the glass composition for glass fibers of the present embodiment may contain oxides of Sr, Ba, Co, Ni, Cu, Cr, Mo, W, Y, La, Bi, Gd, Pr, Sc, Pb, Cd or Yb as impurities derived from raw materials in a range of less than 3.00% by mass in total with respect to the total amount of the glass composition for glass fibers. The glass composition for glass fibers may preferably contain the above oxides in a range of less than 2.00% by mass, and more preferably contain the above oxides in a range of less than 1.00% by mass.

[0091] In particular, when the glass composition for glass fibers of the present embodiment contains SrO, BaO, Y2O3, La2O3, Bi2O3, Gd2O3, Pr2O3, Sc2O3 or Yb2O3 as impurities, their contents are each independently in a range of less than 0.40% by mass, more preferably in a range of less than 0.20% by mass, further preferably in a range of less than 0.10% by mass, particularly preferably in a range of less than 0.05% by mass, especially preferably in a range of less than 0.01% by mass, and most preferably in a range of less than 0.001% by mass with respect to the total amount of the glass composition for glass fibers.

[0092] Regarding the measurement of the content ratio of each component of the above glass composition for glass fibers, the content ratio of Li as a light element can be measured using an ICP emission spectroscopic analyzer. In addition, the content ratios of other elements can be measured using a wavelength-dispersive X-ray fluorescence analyzer.

[0093] As a measurement method, the following method can be cited. First, put the glass batch into a platinum crucible and keep it at a temperature of 1650 °C in an electric furnace for 6 hours, and melt it while stirring to obtain a homogeneous molten glass. Alternatively, put the glass fibers into a platinum crucible and keep it at a temperature of 1650 °C in an electric furnace for 6 hours, and melt it while stirring to obtain a homogeneous molten glass.

[0094] The above glass batch is prepared by mixing glass raw materials. Additionally, when there are organic substances attached to the surface of the above glass fibers or when the glass fibers are mainly included as reinforcing materials in organic substances (resins), for example, heating in a muffle furnace at 300 to 650 °C for about 0.5 to 24 hours, etc., the organic substances are removed before use.

[0095] Next, the obtained molten glass is poured onto a carbon plate to form glass chips, and then the glass chips are crushed and pulverized to obtain glass powder.

[0096] Next, for the determination of Li as a light element, the above glass powder is heated and decomposed with an acid, and then quantitative analysis is performed using an ICP emission spectroscopic analysis device. For the determination of other elements, after the above glass powder is formed into a disk shape using a press, quantitative analysis is performed using a wavelength dispersive X-ray fluorescence analysis device. The quantitative analysis using a wavelength dispersive X-ray fluorescence analysis device can be specifically implemented as follows: Standard curve specimens are prepared based on the results measured by the fundamental parameter method, and analysis is performed by the standard curve method. It should be noted that the content of each component in the calibration curve specimen can be quantitatively analyzed using an ICP emission spectroscopic analysis device. The content and total amount of each component can be calculated by converting these quantitative analysis results into oxides, and the content ratio (mass %) of each of the above components can be obtained based on these values.

[0097] The glass fibers of the present embodiment can be formed from the glass compositions for glass fibers of the above various forms of the present embodiment in the following manner. First, based on the components contained in the ore as the glass raw material, the content ratio of each component, and the volatilization amount of each component during the melting process, the glass raw materials are formulated in such a way as to form the composition of the glass compositions for glass fibers of the above various forms of the present embodiment. Next, the formulated glass raw materials (glass batch) are supplied to a melting furnace and melted in a temperature region above 1000 poise, specifically in a temperature range of 1450 to 1650 °C. Next, the glass batch (molten glass) melted at the temperature in the above range is ejected from 100 to 8000 nozzle heads or holes of a sleeve controlled at a specified temperature, and while being stretched by high-speed winding, the molten glass is cooled and solidified, thereby forming glass single fibers (glass filaments).

[0098] When forming the glass fiber of the present embodiment, the glass filaments ejected from one nozzle head or orifice, cooled and solidified generally have a circular cross-sectional shape and have a diameter in the range of 2.0 to 35.0 μm. For applications that require a lower coefficient of linear expansion, the above-mentioned glass filaments preferably have a diameter in the range of 3.0 to 6.0 μm, and more preferably have a diameter in the range of 3.0 to 4.5 μm. On the other hand, when the nozzle head has a non-circular shape and has protrusions and notches for quenching molten glass, by controlling the temperature conditions, glass filaments having a non-circular (e.g., elliptical, oblong) cross-sectional shape can be obtained. When the above-mentioned glass filaments have an elliptical or oblong cross-sectional shape, the ratio of the major axis to the minor axis (major axis / minor axis) of the cross-sectional shape is, for example, in the range of 2.0 to 10.0, and the fiber diameter (converted fiber diameter) when the cross-sectional area is converted into a perfect circle is, for example, in the range of 2.0 to 35.0 μm.

[0099] The glass fiber of the present embodiment generally adopts the shape of a glass fiber bundle (glass roving) formed by bundling the above-mentioned glass filaments in the range of 10 to 8000 filaments, and has a weight in the range of 0.3 to 10000.0 tex (g / km).

[0100] The glass fiber of the present embodiment can adopt various forms such as yarns, fabrics, knitted fabrics, non-woven fabrics (including chopped strand mats, multi-axial non-woven fabrics), chopped strands, rovings, powders, etc. obtained by further processing the above-mentioned glass rovings.

[0101] For the glass composition for glass fibers in the above various forms according to the present embodiment, the elastic modulus of the obtained glass fiber is in the range of 70.0 GPa or more, preferably in the range of 75.0 GPa or more, more preferably in the range of 78.0 GPa or more, further preferably in the range of 79.0 GPa or more. Although the upper limit is not particularly limited, it is particularly preferably in the range of 80.0 to 90.0 GPa, and especially preferably in the range of 81.0 to 86.0 GPa.

[0102] In addition, for the glass composition for glass fibers in the above various forms according to the present embodiment, the coefficient of linear expansion of the obtained glass fiber is in the range of 3.0 ppm / K or less, preferably in the range of 2.9 ppm / K or less, more preferably in the range of less than 2.5 ppm / K. Although the lower limit is not particularly limited, it is further preferably in the range of 1.5 to 2.3 ppm / K, and particularly preferably in the range of 1.8 to 2.2 ppm / K.

[0103] In addition, for the glass composition for glass fibers in each form according to the present embodiment, the dielectric constant of the obtained glass fibers at a measurement frequency of 10 GHz is preferably in the range of 4.4 to 5.4, and the tangent of the dielectric loss angle of the obtained glass fibers at a measurement frequency of 10 GHz is preferably in the range of 0.0030 to 0.0060.

[0104] For the purposes of improving the bundling property of glass filaments, improving the adhesiveness between glass fibers and resins, improving the uniform dispersion of glass fibers in a mixture of glass fibers and resins or inorganic materials, etc., an organic substance can be coated on the surface of the glass fibers of the present embodiment. Examples of such organic substances include: starch, polyurethane resin, epoxy resin, vinyl acetate resin, acrylic resin, modified polypropylene (especially carboxylic acid-modified polypropylene), copolymers of (poly)carboxylic acids (especially maleic acid) and unsaturated monomers, etc.

[0105] In addition, the glass fibers of the present embodiment, in addition to being coated with these resins, can also be coated with a resin composition containing a silane coupling agent, a lubricant, a surfactant, etc. In addition, the glass fibers of the present embodiment may not contain the above resins, but be coated with a treatment agent composition containing a silane coupling agent, a surfactant, etc.

[0106] Based on the mass of the glass fibers of the present embodiment in a state not coated with a resin composition or a treatment agent composition, such a resin composition or a treatment agent composition coats the glass fibers in a proportion range of 0.1 to 2.0% by mass.

[0107] It should be noted that the process of coating an organic substance on the glass fibers can be carried out, for example, in the following manner: in the manufacturing process of the glass fibers, a resin solution or a resin composition solution is coated on the glass fibers by a known method such as a roll coater, and then the glass fibers coated with the resin solution or the resin composition solution are dried. In addition, the coating of the glass fibers of the present embodiment in the form of a fabric formed from the above organic substances can be carried out in the following manner: the glass fibers are immersed in a treatment agent composition solution, and then the glass fibers given the treatment agent composition are dried.

[0108] Examples of the above silane coupling agents include: amino silane, chloro silane, epoxy silane, mercapto silane, vinyl silane, acrylic silane, and cationic silane. The above silane coupling agents can be used alone, or two or more of the above silane coupling agents can be used in combination.

[0109] Examples of the aminosilane include: γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-N’-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, and the like.

[0110] Examples of the chlorosilane include γ-chloropropyltrimethoxysilane and the like.

[0111] Examples of the epoxysilane include γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and the like.

[0112] Examples of the mercaptosilane include γ-mercaptopropyltrimethoxysilane and the like.

[0113] Examples of the vinylsilane include vinyltrimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, and the like.

[0114] Examples of the acrylatesilane include γ-methacryloxypropyltrimethoxysilane and the like.

[0115] Examples of the cationicsilane include N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, N-phenyl-3-aminopropyltrimethoxysilane hydrochloride, and the like.

[0116] Examples of the above lubricants include: modified silicone oil, animal oil and its hydrogenated additive, vegetable oil and its hydrogenated additive, animal wax, vegetable wax, mineral wax, condensate of higher saturated fatty acid and higher saturated alcohol, polyethyleneimine, polyalkyl polyamine alkylene flax glycoside derivative, fatty acid amide, quaternary ammonium salt. The above lubricants can be used alone or two or more of the above lubricants can be used in combination.

[0117] Examples of the animal oil include beef tallow and the like.

[0118] Examples of the vegetable oil include: soybean oil, coconut oil, rapeseed oil, palm oil, castor oil, and the like.

[0119] Examples of the animal wax include beeswax, lanolin, and the like.

[0120] Examples of the vegetable wax include candelilla wax, carnauba wax, and the like.

[0121] Examples of the mineral wax include paraffin wax, montan wax, and the like.

[0122] Examples of the condensate of higher saturated fatty acid and higher saturated alcohol include stearic acid esters such as lauryl stearate and the like.

[0123] As fatty acid amides, examples include dehydration condensates of polyethylene polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, etc. with fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, etc.

[0124] As quaternary ammonium salts, examples include alkyltrimethylammonium salts such as lauryltrimethylammonium chloride, etc.

[0125] As surfactants, examples include nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants. These surfactants can be used alone, or two or more of them can be used in combination.

[0126] As nonionic surfactants, examples include: ethylene oxide-propylene oxide alkyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene-polyoxypropylene-block copolymer ethers, alkyl polyoxyethylene-polyoxypropylene-block copolymer ethers, polyoxyethylene fatty acid esters, polyoxyethylene fatty acid monoesters, polyoxyethylene fatty acid diesters, polyoxyethylene sorbitan fatty acid esters, ethylene oxide adducts of glycerol fatty acid esters, polyoxyethylene stearyl ethers, ethylene oxide adducts of hydrogenated castor oil, ethylene oxide adducts of alkylamines, ethylene oxide adducts of fatty acid amides, glycerol fatty acid esters, polyglycerol fatty acid esters, pentaerythritol fatty acid esters, sorbitan fatty acid esters, sorbitan anhydride fatty acid esters, sucrose fatty acid esters, polyol alkyl ethers, fatty acid alkanolamides, alkynediols, acetylene alcohols, ethylene oxide adducts of alkynediols, ethylene oxide adducts of alkynols, etc.

[0127] As cationic surfactants, examples include: alkyl dimethyl benzyl ammonium chloride, alkyl trimethyl ammonium chloride, alkyl dimethyl ethyl ammonium ethyl sulfate, higher alkylamine acetates, ethylene oxide adducts of higher alkylamine hydrochlorides such as higher alkylamine hydrochlorides, condensates of higher fatty acids with polyalkylene polyamines, salts of esters of higher fatty acids and alkanolamines, salts of higher fatty acid amides, imidazoline-type cationic surfactants, alkyl pyridinium salts, etc.

[0128] As anionic surfactants, examples include: higher alcohol sulfate esters, higher alkyl ether sulfate esters, α-olefin sulfate esters, alkylbenzene sulfonates, α-olefin sulfonates, reaction products of fatty acid halides and N-methyltaurine, dialkyl sulfosuccinate salts, higher alcohol phosphate esters, phosphate esters of ethylene oxide adducts of higher alcohols, etc. As amphoteric surfactants, examples include amino acid-type amphoteric surfactants such as alkali metal salts of alkylaminopropane, betaine-type such as alkyl dimethyl betaine, imidazoline-type amphoteric surfactants, etc.

[0129] The glass fiber fabric of the present embodiment contains the glass fiber of the present embodiment described above. Specifically, the glass fiber fabric of the present embodiment can be obtained by the following method: using the above glass fiber of the present embodiment as at least a part of the warp or weft yarns and weaving them using a loom known per se. Examples of the above loom include: jet looms, water jet looms and other jet type looms, shuttle looms, rapier looms, etc. In addition, examples of the weaving method of the above loom include plain weave, satin weave, basket weave, twill weave, etc., and from the viewpoint of manufacturing efficiency, plain weave is preferably adopted.

[0130] In the glass fiber fabric of the present embodiment, preferably, the above glass fiber of the present embodiment is a mass of 0.9 - 600.0 tex (g / km) obtained by bundling 35 - 20000 glass filaments with a diameter in the range of 3.0 - 21.0 μm and applying 0 - 1.0 twists per 25 mm.

[0131] In the glass fiber fabric of the present embodiment, when the above glass fiber of the present embodiment is used as the warp or weft yarn, preferably, the warp yarn density is in the range of 10 - 120 ends per 25 mm, and the weft yarn density is in the range of 10 - 120 picks per 25 mm.

[0132] The glass fiber fabric of the present embodiment can also be subjected to degreasing treatment, surface treatment and fibrillating treatment after weaving.

[0133] Examples of the above degreasing treatment include the following treatment: placing the above glass fiber fabric in a heating furnace at an atmosphere temperature in the range of 350 °C - 400 °C for a time in the range of 40 - 80 hours, and heating and decomposing the organic substances attached to the glass fiber.

[0134] Examples of the above surface treatment include the following treatment: impregnating the above glass fiber fabric in a solution containing the above silane coupling agent or a solution containing the above silane coupling agent and the above surfactant, and after removing the excess water, heating and drying it in the temperature range of 80 - 180 °C for 1 - 30 minutes.

[0135] Examples of the above fibrillating treatment include, for example, the following treatment: while applying a tension in the range of 30 - 200 N to the warp yarns of the above glass fiber fabric, performing fibrillating using water pressure, fibrillating using high-frequency vibration with a liquid as the medium, fibrillating using fluid pressure with surface pressure, fibrillating using roller pressing, etc., to expand the yarn width of the warp and weft yarns.

[0136] The glass fiber fabric of the present embodiment preferably has a mass per unit area in the range of 7.0 - 750.0 g / m 2 and preferably has a thickness in the range of 8.0 - 500.0 μm.

[0137] The yarn width of the warp of the glass fiber fabric of this embodiment is preferably in the range of 110 to 600 μm, and the yarn width of the weft is preferably in the range of 110 to 600 μm.

[0138] The glass fiber fabric of this embodiment may have a surface treatment layer containing the above silane coupling agent or a surface treatment layer containing the above silane coupling agent and the above surfactant. When the glass fiber fabric of this embodiment contains the above surface treatment layer, the surface treatment layer has a mass in the range of, for example, 0.03 to 1.50% by mass based on the total amount of the glass fiber fabric containing the surface treatment layer.

[0139] The glass fiber reinforced resin composition of this embodiment contains the aforementioned glass fiber of this embodiment. Specifically, in a glass fiber reinforced resin composition containing a resin (thermoplastic resin or thermosetting resin), glass fiber, and other additives, the glass fiber reinforced resin composition of this embodiment contains, for example, 10 to 90% by mass of glass fiber based on the total amount of the glass fiber reinforced resin composition. In addition, the glass fiber reinforced resin composition of this embodiment contains, for example, 90 to 10% by mass of resin based on the total amount of the glass fiber reinforced resin composition, and contains other additives in the range of 0 to 40% by mass.

[0140] Examples of the thermoplastic resin used to form the glass fiber reinforced resin composition of the present embodiment include: polyethylene, polypropylene, polystyrene, styrene / maleic anhydride resin, styrene / maleimide resin, polyacrylonitrile, acrylonitrile / styrene (AS) resin, acrylonitrile / butadiene / styrene (ABS) resin, chlorinated polyethylene / acrylonitrile / styrene (ACS) resin, acrylonitrile / ethylene / styrene (AES) resin, acrylonitrile / styrene / methyl acrylate (ASA) resin, styrene / acrylonitrile (SAN) resin, methacrylic resin, polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyamide, polyacetal, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polycarbonate, polyarylene sulfide, polyethersulfone (PES), polyphenylsulfone (PPSU), polyphenylene ether (PPE), modified polyphenylene ether (m-PPE), polyaryl ether ketone, liquid crystal polymer (LCP), fluororesin, polyetherimide (PEI), polyarylate (PAR), polysulfone (PSF), polyamideimide (PAI), polyaminobismaleimide (PABM), thermoplastic polyimide (TPI), polyethylene naphthalate (PEN), ethylene / vinyl acetate (EVA) resin, ionomer (IO) resin, polybutadiene, styrene / butadiene resin, polybutene, polymethylpentene, olefin / vinyl alcohol resin, cyclic olefin resin, cellulose resin, polylactic acid, etc.

[0141] Examples of the above-mentioned polyethylene include: high-density polyethylene (HDPE), medium-density polyethylene, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ultra-high molecular weight polyethylene, etc.

[0142] Examples of the above-mentioned polypropylene include: isotactic polypropylene, atactic polypropylene, syndiotactic polypropylene, and mixtures of the above-mentioned polypropylenes.

[0143] Examples of the above-mentioned polystyrene include general polystyrene (GPPS) which is atactic polystyrene having an atactic structure, high-impact polystyrene (HIPS) obtained by adding a rubber component to GPPS, and atactic polystyrene having an atactic structure.

[0144] Examples of the above-mentioned methacrylic resin include: polymers obtained by polymerizing a single methacrylic resin selected from acrylic acid, methacrylic acid, styrene, methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, and vinyl fatty acid ester, or copolymers obtained by copolymerizing two or more of the above-mentioned methacrylic resins.

[0145] As the above-mentioned polyvinyl chloride, examples thereof include: vinyl chloride homopolymers polymerized by using known emulsion polymerization methods, suspension polymerization methods, minisuspension polymerization methods, bulk polymerization methods, etc., copolymers of monomers capable of copolymerizing with vinyl chloride monomers, graft copolymers obtained by graft-polymerizing vinyl chloride monomers to polymers, and the like.

[0146] As the polyamide, examples thereof include: polycaprolactam (polyamide 6), polyhexamethylene adipamide (polyamide 66), polybutylene adipamide (polyamide 46), polyhexamethylene sebacamide (polyamide 410), polypentamethylene adipamide (polyamide 56), polypentamethylene sebacamide (polyamide 510), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecanamide (polyamide 612), polydecamethylene adipamide (polyamide 106), sebacoyl sebacamide (polyamide 1010), polydecamethylene dodecanamide (polyamide 1012), undecanamide (polyamide 11), polyhexamethylene hexanediamide (polyamide 116), dodecanamide (polyamide 12), polyhexamethylene -xylylenediamine adipamide (polyamide XD6), sebacoyl sebacamide (polyamide XD10), polyhexamethylene isophthalamide (polyamide MXD6), poly-p-xylylene adipamide (polyamide PXD6), poly-p-phenylene terephthalamide (polyamide 4T), polypentamethylene terephthalamide (polyamide 5T), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), nonamethylene terephthalamide (polyamide 9T), poly-p-phenylene sebacamide (polyamide 10T), polyundecamethylene terephthalamide (polyamide 11T), polydodecamethylene terephthalamide (polyamide 12T), polytetramethylene isophthalamide (polyamide 4I), poly-bis(3-methyl-4-aminohexyl)methane terephthalamide (polyamide PACMT), poly-bis(3-methyl-4-aminohexyl)methane isophthalamide (polyamide PACMI), poly-bis(3-methyl-4-aminohexyl)methane dodecanamide (polyamide PACM12), poly-bis(3-methyl-4-aminohexyl)methane tetradecanediamide (polyamide PACM14), etc. Copolymers obtained by combining one or two or more of these components or mixtures thereof, and the like.

[0147] As the above-mentioned polyacetal, examples thereof include: homopolymers having oxy-methylene units as the main repeating units, copolymers mainly composed of oxy-methylene units and containing oxy-alkylene units having 2 to 8 adjacent carbon atoms in the main chain, and the like.

[0148] As the above-mentioned polyethylene terephthalate, examples thereof include polymers obtained by polycondensing ethylene glycol with terephthalic acid or its derivatives.

[0149] As the above-mentioned polybutylene terephthalate, polymers obtained by polycondensing 1,4-butanediol with terephthalic acid or its derivatives can be cited, etc.

[0150] As the above-mentioned polypropylene terephthalate, polymers obtained by polycondensing 1,3-propanediol with terephthalic acid or its derivatives can be cited, etc.

[0151] As the above-mentioned polycarbonate, polymers obtained by the transesterification method of reacting a dihydroxy diaryl compound with a carbonate such as diphenyl carbonate in a molten state, or polymers obtained by the phosgene method of reacting a dihydroxy aryl compound with phosgene can be cited.

[0152] As the above-mentioned polyarylene sulfide, linear polyphenylene sulfide, crosslinked polyphenylene sulfide polymerized to a high molecular weight by a curing reaction after polymerization, polyphenylene sulfide sulfone, polyphenylene sulfide ether, polyphenylene sulfide ketone, etc. can be cited.

[0153] As the above-mentioned modified polyphenylene ether, polymer alloys of poly(2,6-dimethyl-1,4-phenylene) ether and polystyrene, polymer alloys of poly(2,6-dimethyl-1,4-phenylene) ether and styrene / butadiene copolymer, polymer alloys of poly(2,6-dimethyl-1,4-phenylene) ether and styrene / maleic anhydride copolymer, polymer alloys of poly(2,6-dimethyl-1,4-phenylene) ether and polyamide, polymer alloys of poly(2,6-dimethyl-1,4-phenylene) ether and styrene / butadiene / acrylonitrile copolymer, etc. can be cited.

[0154] As the above-mentioned polyaryletherketone, polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), etc. can be cited.

[0155] As the above-mentioned liquid crystal polymer (LCP), (co)polymers composed of one or more structural units selected from the following components can be cited, etc., and the components are: aromatic hydroxycarbonyl units, aromatic dihydroxy units, aromatic dicarbonyl units, aliphatic dihydroxy units, aliphatic dicarbonyl units, etc. as thermotropic liquid crystal polyesters.

[0156] As the above-mentioned fluororesin, polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), fluorinated ethylene propylene resin (FEP), fluorinated ethylene tetrafluoroethylene resin (ETFE), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene / trifluorochloroethylene resin (ECTFE), etc. can be cited.

[0157] As the above-mentioned ionomer (IO) resin, examples include: polymers obtained by copolymerizing an olefin or styrene with an unsaturated carboxylic acid and neutralizing a part of the carboxyl groups with metal ions, etc.

[0158] As the above-mentioned olefin / vinyl alcohol resin, examples include: ethylene / vinyl alcohol copolymer, propylene / vinyl alcohol copolymer, saponified ethylene / vinyl acetate copolymer, saponified propylene / vinyl acetate copolymer, etc.

[0159] As the above-mentioned cyclic olefin resin, examples include: monocyclic compounds such as cyclohexene, polycyclic compounds such as tetracyclic cycloolefins, polymers of cyclic olefin monomers, etc.

[0160] As the above-mentioned polylactic acid, examples include: poly-L-lactic acid which is a homopolymer of the L-form, poly-D-lactic acid which is a homopolymer of the D-form, or stereocomplex polylactic acid which is a mixture thereof, etc.

[0161] As the cellulose resin, examples include: methyl cellulose, ethyl cellulose, hydroxy cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, cellulose acetate, cellulose propionate, and cellulose butyrate, etc. Further, as the above-mentioned thermosetting resin forming the glass fiber reinforced resin composition of the present embodiment, examples include: unsaturated polyester resin, vinyl ester resin, epoxy (EP) resin, melamine (MF) resin, phenolic resin (PF), polyurethane resin (PU), polyisocyanate, polyisocyanurate, polyimide (PI), urea formaldehyde (UF) resin, silicon (SI) resin, furan (FR) resin, benzoguanamine (BR) resin, alkyd resin, xylene resin, bismaleimide triazine (BT) resin, diallyl phthalate resin (PDAP), thermosetting polyphenylene ether resin, etc.

[0162] Specifically, as the unsaturated polyester resin, examples include resins obtained by subjecting an aliphatic unsaturated dicarboxylic acid and an aliphatic diol to an esterification reaction.

[0163] As the vinyl ester resin, examples include: divinyl ester resin, novolac type vinyl ester resin.

[0164] Examples of epoxy resins include: bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol E type epoxy resins, bisphenol S type epoxy resins, bisphenol M type epoxy resins (4,4'-(1,3-phenylene diisopropylidene) bisphenol type epoxy resins), bisphenol P type epoxy resins (4,4'-(1,4-phenylene diisopropylidene) bisphenol type epoxy resins), bisphenol Z type epoxy resins (4,4'-cyclohexene bisphenol type epoxy resins), phenol novolac type epoxy resins, cresol novolac type epoxy resins, tetraphenol ethane novolac type epoxy resins, novolac type epoxy resins having a condensed polycyclic aromatic hydrocarbon structure, biphenyl type epoxy resins, xylylene type epoxy resins or aralkyl type epoxy resins such as phenyl aralkyl type epoxy resins, naphthylene ether type epoxy resins, naphthol type epoxy resins, naphthalenediol type epoxy resins, bifunctional or tetrafunctional epoxy type naphthalene resins, binaphthyl type epoxy resins, naphthalene aralkyl type epoxy resins, anthracene type epoxy resins, phenoxy type epoxy resins, dicyclopentadiene type epoxy resins, norbornene type epoxy resins, adamantane type epoxy resins, fluorene type epoxy resins, etc.

[0165] Examples of melamine resins include polymers formed by the polycondensation of melamine (2,4,6-triamino-1,3,5-triazine) and formaldehyde.

[0166] Examples of phenolic resins include: phenolic resins such as phenol novolac resins, cresol novolac resins, bisphenol A type novolac resins, etc., resole type phenolic resins such as hydroxymethyl type resole resins, dimethylene ether type resole resins, etc., or resins such as aryl aralkyl type phenolic resins, or resins formed by combining one resin or two or more resins.

[0167] Examples of urea-formaldehyde resins include resins obtained by the condensation of urea and formaldehyde.

[0168] The above-mentioned thermoplastic resins or the above-mentioned thermosetting resins can be used alone or in combination of two or more.

[0169] Examples of the above-mentioned other additives include: reinforcing fibers other than glass fibers (e.g., carbon fibers, metal fibers), fillers other than glass fibers (e.g., glass powder, talc, mica), flame retardants, ultraviolet absorbers, heat stabilizers, antioxidants, antistatic agents, flow improvers, anti-blocking agents, lubricants, nucleating agents, antibacterial agents, pigments, etc.

[0170] The glass fiber reinforced resin composition of this embodiment can be obtained, for example, by the following method: in a twin-screw kneader, the above-mentioned chopped strands and the above-mentioned resin are kneaded to form resin pellets, and the obtained resin pellets are used for injection molding to obtain the glass fiber reinforced resin composition.

[0171] In addition, the above glass fiber reinforced resin composition can be obtained by the following well-known molding methods: injection compression molding method, two-color molding method, hollow molding method, foam molding method (including supercritical fluid foam molding method), insert molding method, in-mold coating molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, lamination molding method, compression molding method, blow molding method, stamping molding method, melting method, hand lay-up molding method, spraying method, resin transfer molding method, sheet molding compound molding method, bulk molding compound molding method, pultrusion molding method, filament winding method, etc.

[0172] In addition, the glass fiber reinforced resin composition of the present embodiment can be a prepreg obtained by impregnating the above resin into the above glass fiber fabric of the present embodiment by a method known per se and semi-curing it.

[0173] As uses of the molded article formed from the glass fiber reinforced resin composition of the present embodiment, for example, the following can be cited: electronic equipment casings, electronic parts, vehicle exterior parts, vehicle interior parts, vehicle engine peripheral parts, muffler-related parts, high-pressure tanks, composite materials for wind energy, etc.

[0174] As electronic components, printed wiring boards and the like can be cited.

[0175] As vehicle exterior parts, bumpers, fenders, engine hoods, air dams, wheel covers, etc. can be cited.

[0176] As vehicle interior parts, door trims, ceiling materials, etc. can be cited.

[0177] As vehicle engine peripheral parts, oil pans, engine hoods, intake manifolds, exhaust manifolds, etc. can be cited.

[0178] As muffler-related parts, muffling parts and the like can be cited.

[0179] As composite materials for wind energy, wind turbine blades and the like can be cited.

[0180] It should be noted that the glass fiber of the present embodiment can be used not only for the glass fiber reinforced resin composition of the present embodiment but also as a reinforcing material for inorganic materials such as gypsum and cement. For example, when used as a reinforcing material for gypsum, particularly for gypsum boards having a thickness range of 4 to 60 mm, the gypsum contains glass fibers having the above-described glass composition in a range of 0.1 to 4.0% by mass based on the total mass of the gypsum.

[0181] Next, examples and comparative examples of the present invention are shown.

[0182] Examples

[0183] 〔Examples 1 to 12, Comparative Examples 1 to 6〕

[0184] Prepare each glass batch to make it the composition of the glass compositions for each glass fiber of Examples 1 to 12 and Comparative Examples 1 to 6 shown in Tables 1 to 3. Measure the elastic modulus, coefficient of linear expansion, dielectric constant, and dielectric loss tangent of each of the prepared glass materials by the following measurement methods, and evaluate the clarity of the molten glass and the uniformity of the composition of the molten glass by the following evaluation methods. The results are shown in Tables 1 to 3.

[0185] It should be noted that Comparative Example 3 has the same composition as Example 1 in PCT / JP2023 / 014110, and Comparative Example 4 has the same composition as Example 2 in Japanese Patent Application 2023-029848.

[0186] In addition, the elastic modulus of the glass fiber obtained from the glass composition for glass fiber of Example 1 is 82.6 GPa, the coefficient of linear expansion is 2.2 ppm / K, the dielectric constant at 10 GHz is 4.7, the dielectric loss tangent at 10 GHz is 0.0043, the dielectric constant at 28 GHz is 4.6, the dielectric loss tangent at 28 GHz is 0.0057, the dielectric constant at 56 GHz is 4.6, the dielectric loss tangent at 56 GHz is 0.0071. The clarity of the molten glass obtained from this composition is "A", and the compositional uniformity is 0.6%.

[0187] 〔Measurement method for elastic modulus〕

[0188] First, put the glass batch adjusted to the composition of the glass composition for the above glass fiber into a platinum crucible with a diameter of 80 mm, heat it at a temperature of 1650 °C for 6 hours to melt it, and then take it out of the platinum crucible to obtain a homogeneous glass block or glass chips. Then, anneal the obtained glass block or glass chips at a temperature of 750 °C for 8 hours to obtain a test piece. Then, use a cutting machine, such as a diamond tool and a grinding machine, to process the above test piece into a test piece for measuring the elastic modulus with dimensions of 50 mm × 50 mm × 5 mm. Use this test piece for measuring the elastic modulus and measure the elastic modulus by the ultrasonic pulse method in accordance with JIS R 1602∶1995.

[0189] 〔Measurement method for coefficient of linear expansion〕

[0190] First, a test piece obtained in the same manner as in the determination of the elastic modulus described above is processed into a test piece for linear expansion coefficient measurement with dimensions of 4 mm × 4 mm × 20 mm using a cutting machine, such as a diamond tool, and a grinding machine. Next, the obtained test piece for linear expansion coefficient measurement is heated at a heating rate of 10 °C / minute, and in the temperature range of 50 °C to 200 °C, the elongation is measured using a thermal expansion rate measuring device (manufactured by NETZSCH, product name: DIL402), and the linear expansion coefficient is calculated based on this elongation.

[0191] 〔Evaluation method for clarity〕

[0192] First, a glass batch adjusted to the composition of the glass composition for glass fibers is placed in a platinum crucible with a diameter of 80 mm and melted at a temperature of 1600 °C for 3 hours, and then taken out from the platinum crucible to obtain a glass block. Next, the obtained glass block is heated at a temperature of 750 °C for 2 hours and then cooled to room temperature over 8 hours to perform annealing to obtain a test piece. Next, using a cutting machine, such as a diamond tool, a 10 mm × 15 mm-sized portion is cut out from the center of the obtained test piece, and its surface is polished with #2000 abrasive paper. Next, the number of bubbles contained in the above test piece whose surface has been polished is measured using an optical microscope. A case where the number of bubbles per gram of the glass block is less than 150 is evaluated as "A", a case where the number of bubbles is 150 or more and less than 1000 is evaluated as "B", and a case where the number of bubbles is 1000 or more is evaluated as "C".

[0193] 〔Evaluation method for compositional uniformity〕

[0194] First, using a cutting machine, such as a diamond tool, a test piece with upper and lower surfaces of 10 mm × 15 mm in size is cut out from the center of a test piece obtained in the same manner as in the evaluation method for clarity described above, and its surface is polished with #2000 abrasive paper. Next, the composition of the side surface of the above test piece whose surface has been polished is analyzed by EDS (energy dispersive spectrometry) to evaluate the compositional difference between the upper surface region and the bottom surface region. Specifically, a field emission scanning electron microscope (FE-SEM, manufactured by JEOL Ltd., model: JSM-IT800) and an energy dispersive spectrometry device (manufactured by JEOL Ltd., model: EDS30mm 2Detector), in any field of view of 100 μm or more, perform area measurement on the area within a range of 1 mm from the upper surface and the bottom surface respectively, and measure the content rate (%) in terms of oxides of each element contained in the glass composition for glass fibers. It should be noted that the content rate in terms of oxides of the element is measured for three different areas of the upper surface area and the bottom surface area respectively, and the average value of the measurement results of the three areas is taken as the content rate in terms of oxides of each element. Calculate the absolute value of the difference between the content rate in terms of oxides in the upper surface area and the content rate in terms of oxides in the bottom surface area for each element, and calculate all detected elements. The value obtained by adding up the absolute values of the content rate differences of all elements is taken as the compositional uniformity. It should be noted that the smaller the value of the above compositional uniformity, the smaller the deviation of the composition of the molten glass (the better the uniformity).

[0195] [Measurement method of dielectric constant and dielectric loss tangent]

[0196] Regarding the measurement of the dielectric constant (dielectric constant Dk) and the dielectric loss tangent (dissipation factor Df) below 10 GHz, first, grind the test piece to make a ground test piece of 80 mm × 3 mm (thickness 1 mm). Then, after subjecting the obtained ground test piece to absolute drying, store it in a room at 23°C and a humidity of 60% for 24 hours. Then, according to JIS C 2565∶1992, use the cavity resonator method dielectric constant measuring device ADMS01Oc1 (product name) manufactured by AET, Inc. to measure the dielectric constant (dielectric constant Dk) and the dielectric loss tangent (dissipation factor Df) of the above obtained ground test piece at 10 GHz.

[0197] Regarding the dielectric constant (dielectric constant Dk) and the dielectric loss tangent (dissipation factor Df) above 10 GHz, first, grind the test piece to make a ground test piece of 37 mm × 37 mm (thickness 0.3 mm). Then, after subjecting the obtained ground test piece to absolute drying, store it in a room at 25°C and a humidity of 50% for 24 hours. Then, measure the dielectric constant (dielectric constant Dk) and the dielectric loss tangent (dissipation factor Df) of the above obtained ground test piece at 28 GHz and 56 GHz by the balanced circular plate resonator method.

[0198] (Table 1)

[0199]

[0200] (Table 2)

[0201]

[0202] (Table 3)

[0203]

[0204] As can be seen from Table 1 and Table 2, for the glass compositions for glass fibers according to Examples 1 to 10 below, it can be seen that high elastic modulus and low linear expansion coefficient can be taken into account, the clarification of molten glass can be improved, and the compositional uniformity of molten glass can be achieved. Among them, in Examples 1 to 10, SiO2 in the range of 42.00 to 70.00% by mass, Al2O3 in the range of 10.00 to 30.00% by mass, MgO in the range of 0.00 to 8.00% by mass, CaO in the range of 0.00 to 5.00% by mass, ZnO in the range of 2.00 to 25.00% by mass, TiO2 in the range of 0.00 to 5.00% by mass, P2O5 in the range of 2.00 to 17.30% by mass and MxOy in the range of 0.01 to 2.00% by mass in total are included relative to the total amount, and the content rate Z of the ZnO, the content rate P of the P2O5, and the content rate M of the MxOy satisfy the formula (1).

[0205] On the other hand, as can be seen from Table 3, for the glass composition for glass fiber of Comparative Example 1 where the value of (Z / P)×M 1 / 2 exceeds 3.554 and is outside the range of the above formula (1), the clarification is low and the compositional uniformity of molten glass cannot be achieved. In addition, it can be seen that for the glass composition for glass fiber of Comparative Example 2 where the value of (Z / P)×M 1 / 2 is less than 0.088 and is outside the range of the above formula (1), the clarification is low. It can also be seen that for the glass compositions for glass fibers of Comparative Example 3 and Comparative Example 4 where the content rate of MxOy is 0.00%, the clarification is low and the compositional uniformity of molten glass cannot be achieved. In addition, it can be seen that for the glass composition for glass fiber of Comparative Example 5 where the content rate of ZnO is 0.00%, glass fiber with high elastic modulus cannot be produced. And it can be seen that for the glass composition for glass fiber of Comparative Example 6 where the content rate of P2O5 is 0.01%, glass fiber with low linear expansion coefficient cannot be produced.

Claims

1. A glass composition for glass fibers, characterized in that, it contains SiO2 in the range of 42.00 to 70.00% by mass relative to the total amount, Al2O3 in the range of 10.00 to 30.00% by mass, MgO in the range of 0.00 to 8.00% by mass, CaO in the range of 0.00 to 5.00% by mass, ZnO in the range of 2.00 to 25.00% by mass, TiO2 in the range of 0.00 to 5.00% by mass, P2O5 in the range of 2.00 to 17.30% by mass, and MxOy in the range of 0.01 to 2.00% by mass in total, where MxOy is at least one or more oxides selected from the group consisting of Fe2O3, SnO2, CeO2, MnO2, Sb2O3, and As2O3, the content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy the following formula (1), 0.088 ≤ (Z / P) × M 1 / 2 ≤ 3.554 … (1).

2. The glass composition for glass fibers according to claim 1, characterized in that, the content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy the following formula (2), 0.183 ≤ (Z / P) × M 1 / 2 ≤ 1.775 … (2).

3. The glass composition for glass fibers according to claim 2, characterized in that, it contains Fe2O3 in the range of 0.01 to 2.00% by mass and SnO2 in the range of 0.01 to 2.00% by mass, the content rate F of Fe2O3 and the content rate S of SnO2 satisfy the following formula (3), 0.06 ≤ S / F ≤ 40.75 … (3).

4. The glass composition for glass fibers according to claim 1, characterized in that, the content rate Z of ZnO, the content rate P of P2O5, and the content rate M of MxOy satisfy the following formula (4), 0.183 ≤ (Z / P) × M 1 / 2 ≤ 0.582 … (4).

5. A glass fiber, characterized in that, It contains glass filaments formed from the glass composition for glass fibers according to claim 1.

6. A fiberglass fabric, characterized in that, It contains the glass fibers according to claim 5.

7. A glass fiber reinforced resin composition, characterized in that, It contains the glass fibers according to claim 5.

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