Glass fiber composition

Abstract

Provided is a glass fiber composition having a high elastic modulus and good productivity.　This glass fiber composition is characterized by containing, in mass%, 10 ppm or more of Cr2O3, and is characterized in that Al2O3 / Cr2O3 is more than 150 in mass ratio.

Description

Glass fiber composition

[0001] The present invention relates to a composition for glass fibers.

[0002] Glass fibers (also called glass fibers or glass filaments) are produced by continuously forming (spinning) molten glass into fibers using a forming device called a bushing device (also called a platinum heating vessel) which generally has a roughly rectangular appearance. The bushing device is disposed at the bottom of a pot-shaped vessel which has a function of temporarily retaining molten glass. The bushing device is made of a heat-resistant metal material such as platinum, and is provided with a number of nozzle portions (or orifices) at its bottom. This bushing device allows the molten glass to reach an optimum temperature at the tip of the bushing nozzle, i.e., when its high-temperature viscosity reaches 10 ３ The temperature is controlled so that the temperature (forming temperature Tx) corresponds to dPa·s. The molten glass is then continuously drawn out from a bushing nozzle, rapidly cooled, and formed (spun) into glass fibers.

[0003] When forming glass fibers, if the liquidus temperature Ty of the molten glass exceeds the forming temperature Tx of the glass, crystals that cause devitrification are likely to precipitate in the molten glass near the bushing nozzle. As a result, the bushing nozzle becomes clogged, causing fiber breakage, also known as breakage. For this reason, it is preferable that the liquidus temperature Ty of the molten glass be lower than the forming temperature Tx (i.e., the temperature difference ΔTxy = Tx - Ty > 0), and it is more preferable that the temperature difference ΔTxy be larger. However, increasing the forming temperature Tx increases the temperature difference (ΔTxy) from the liquidus temperature Ty of the molten glass. In this case, the energy required for melting increases, which leads to problems such as increased manufacturing costs and a shortened lifespan of auxiliary equipment such as bushing devices. Therefore, it is preferable to lower the forming temperature Tx.

[0004] As described above, in the production of glass fibers, it is very important to control the molding temperature Tx and the temperature difference ΔTxy. On the other hand, there is a demand for glass fibers with a higher elastic modulus due to the demand for high performance glass fiber-containing composite materials. ２, Al ２ O ３ and MgO glass composition, and SiO ２ , Al ２ O ３ However, since the forming temperature Tx is high and the liquidus temperature Ty is also high, the temperature difference ΔTxy is small, which has caused a problem in productivity.

[0005] Therefore, Patent Document 1 discloses a glass fiber composition aimed at improving the fiberization temperature (i.e., molding temperature Tx) and ΔT (i.e., temperature difference ΔTxy).

[0006] Special Publication No. 2009-514773

[0007] However, the glass fiber composition described in Patent Document 1 cannot be said to achieve a sufficiently high elastic modulus while ensuring a sufficiently low fiberization temperature and a sufficiently large ΔT.

[0008] In view of the above, an object of the present invention is to provide a composition for glass fibers that has a high elastic modulus and good productivity.

[0009] The composition for glass fiber of the present invention contains, in mass %, Cr ２ O ３ Contains 10 ppm or more and, in mass ratio, Al ２ O ３ / Cr ２ O ３ is more than 150. ２ O ３ is an effective component for improving the elastic modulus, but if its content increases, the liquidus temperature Ty increases, resulting in a decrease in the temperature difference ΔTxy and a decrease in productivity. ２ O ３ Although Cr is also an effective component for improving the elastic modulus, it is also a component that suppresses the crystallization and phase separation in the molten glass. ２ O ３ and Al content ２ O ３ and Cr ２ O ３By restricting the ratio of x to y within the above range, it is possible to obtain a glass composition that has a high elastic modulus and good productivity. In the present invention, "x / y" means the value obtained by dividing the content of the x component by the content of the y component.

[0010] The composition for glass fiber of the present invention contains, in mass %, Cr ２ O ３ It is preferable that the content is 10 to 6000 ppm.

[0011] The glass fiber composition of the present invention is a composition containing, in mass ratio, MgO / Cr ２ O ３ As described above, Cr is preferably 20 or more. ２ O ３ is a component effective in improving the elastic modulus. On the other hand, MgO is also a component effective in improving the elastic modulus, but it also functions as a flux that makes it easier to melt glass raw materials. Therefore, by including MgO, it has the effect of reducing the viscosity during glass melting, accelerating bubble removal, and lowering the forming temperature Tx. Therefore, the combination of MgO and Cr ２ O ３ By restricting the ratio to the above range, it is possible to obtain a glass composition that has a high elastic modulus while lowering the forming temperature Tx and that has good productivity.

[0012] The composition for glass fiber of the present invention contains, in mass %, P ２ O ５ Contains 10 to 1000 ppm and has a mass ratio of R ２ O / P ２ O ５ (R ２ O is Li ２ O, Na ２ O and K ２ It is preferable that the total amount of α, β ...

[0013] The composition for glass fiber of the present invention contains, in mass %, Na ２ It is preferable that the composition contains less than 0.8% of O. By doing so, it is possible to obtain a composition for glass fibers that has good productivity while maintaining the elastic modulus.

[0014] The composition for glass fiber of the present invention contains, in mass %, SiO ２ 25-70%, Al ２ O ３ 13-25%, MgO 0.6-25%, CaO 3-15%, B ２ O ３ It is preferable that the content is 0 to less than 3%.

[0015] The composition for glass fiber of the present invention contains, in mass %, Cr ２ O ３ 10~6000ppm, SiO ２ 50-70%, Al ２ O ３ More than 15 to 20%, MgO 1.2 to 15%, CaO 3 to 15%, B ２ O ３ 0 to less than 3%, TiO ２ 0.01 to less than 3%, Na ２ It is preferable that the O content is less than 0.8%.

[0016] The composition for glass fiber of the present invention comprises, in mass ratio, Al ２ O ３ / Cr ２ O ３ It is preferable that the σ is more than 150.

[0017] The glass fiber composition of the present invention is a composition containing, in mass ratio, MgO / Cr ２ O ３ is preferably 20 or more.

[0018] The composition for glass fiber of the present invention comprises, in mass ratio, R ２ O / P ２ O ５ is preferably 0.01 or more.

[0019] The composition for glass fiber of the present invention preferably has a molding temperature Tx of 1,400° C. or less. This allows fiberization at a low temperature, thereby extending the life of fiberization equipment such as bushings and reducing production costs.

[0020] The glass fiber composition of the present invention preferably has a temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty of 30° C. or more. This makes it possible to improve the productivity of the glass fiber composition. The liquidus temperature Ty is a value measured by placing glass powder that passes through a standard 30 mesh sieve (sieve opening 500 μm) and remains on a standard 50 mesh sieve (sieve opening 300 μm) in a platinum boat, holding the boat in a temperature gradient furnace for 16 hours, and then measuring the temperature at which crystals (primary phase) precipitate.

[0021] The composition for glass fiber of the present invention preferably has an elastic modulus E of 80 GPa or more. By doing so, it is possible to obtain a glass fiber-containing composite material that has small distortion with respect to stress and high physical strength.

[0022] The glass fiber composition of the present invention is characterized by containing any one of the above-mentioned compositions for glass fiber.

[0023] The glass fiber-containing composite material of the present invention is characterized by being a composite of the above-mentioned glass fiber and a matrix material.

[0024] According to the present invention, it is possible to provide a composition for glass fibers that has a high elastic modulus and good productivity.

[0025] The composition for glass fiber of the present invention contains, in mass %, Cr ２ O ３ Contains 10 ppm or more and, in mass ratio, Al ２ O ３ / Cr ２ O ３ The glass composition is characterized in that the value of the glass melting point is greater than 150. The reasons for limiting the glass composition as described above are as follows. In the following description of the content of each component, "%" means "mass %" unless otherwise specified.

[0026] Cr ２ O ３ is a component that does not affect the viscosity of molten glass and improves the elastic modulus of glass, and can efficiently improve the elastic modulus of glass without changing the melting conditions. By improving the elastic modulus (or specific elastic modulus) of glass, it is possible to increase the mechanical strength of glass fiber-containing composite materials. Therefore, Cr２ O ３ The lower limit of the content is preferably 10 ppm or more, 20 ppm or more, 30 ppm or more, 31 ppm or more, 32 ppm or more, 33 ppm or more, 34 ppm or more, 35 ppm or more, more than 35 ppm, particularly preferably 36 ppm or more. On the other hand, if the content is too high, Cr in the glass may be increased. ２ O ３ -Al ２ O ３ -MgO-based devitrification occurs, reducing productivity. ２ O ３ The upper limit of the content is 10,000 ppm or less, 8,000 ppm or less, 6,000 ppm or less, 5,000 ppm or less, 4,000 ppm or less, 3,000 ppm or less, 2,000 ppm or less, 1,000 ppm or less, less than 1,000 ppm, 990 ppm or less, 980 ppm or less, 970 ppm or less, 960 ppm or less, 950 ppm or less, 940 ppm or less, 930 ppm or less, 920 ppm or less, 910 ppm or less, 900 ppm or less, less than 900 ppm, 850 ppm or less, 800 ppm or less, 750 ppm or less, particularly 700 ppm or less.

[0027] Cr ２ O ３ -Al ２ O ３ - Cr to suppress the precipitation of MgO-based devitrification ２ O ３ Al to ２ O ３ The ratio of Cr to Cr is an important parameter. If this ratio is too low, ２ O ３ -Al ２ O ３ -MgO-based devitrification occurs, the liquidus temperature Ty increases, and the temperature difference ΔTxy tends to decrease. As a result, the productivity of glass fiber decreases. ２ O ３ / Cr ２ O ３ The lower limit of Al is preferably more than 150, 155 or more, 160 or more, 165 or more, 170 or more, 175 or more, 180 or more, 185 or more, 190 or more, 195 or more, 196 or more, 197 or more, 198 or more, 199 or more, or 200 or more, and particularly preferably more than 200.２ O ３ / Cr ２ O ３ If it is too large, Cr ２ O ３ -Al ２ O ３ Since devitrification of the -MgO system is likely to occur, the upper limit is preferably 10,000 or less, 8,000 or less, 6,000 or less, and particularly preferably 5,000 or less.

[0028] Cr ２ O ３ -Al ２ O ３ - Cr to suppress the precipitation of MgO-based devitrification ２ O ３ The ratio of MgO to Al ２ O ３ / Cr ２ O ３ It is equally important. ２ O ３ If the ratio of MgO to Cr is too low, ２ O ３ -Al ２ O ３ -MgO-based devitrification occurs, and the liquidus temperature Ty increases, tending to reduce the temperature difference ΔTxy. As a result, the productivity of glass fiber decreases. Therefore, MgO / Cr ２ O ３ The lower limit of is preferably 20 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, more than 80, 81 or more, 82 or more, 85 or more, 90 or more, 95 or more, 100 or more, more than 100, 105 or more, 110 or more, 115 or more, 116 or more, 117 or more, 118 or more, 119 or more, 120 or more, and particularly preferably more than 120. ２ O ３ If it is too large, Cr ２ O ３ -Al ２ O ３ Since MgO-based devitrification is likely to occur, the upper limit is 10,000 or less, 8,000 or less, 6,000 or less, 5,000 or less, 4,000 or less, 3,900 or less, 3,800 or less, 3,700 or less, 3,600 or less, 3,500 or less, 3,400 or less, 3,300 or less, 3,200 or less, 3,100 or less, particularly 3,000 or less.

[0029] Components that may be contained in the composition for glass fibers of the present invention will be described below.

[0030] Na ２ O is Cr ２ O ３ -Al ２ O ３ - A component that suppresses the precipitation of MgO-based devitrification, and further, a component that reduces the viscosity during glass melting, promotes bubble removal, and lowers the molding temperature Tx during glass fiber molding. ２ The lower limit of the O content is preferably 0% or more, 0.001% or more, 0.002% or more, 0.003% or more, 0.004% or more, 0.005% or more, 0.006% or more, 0.007% or more, 0.008% or more, 0.009% or more, or 0.01% or more, particularly preferably more than 0.01%. ２ If the O content is too high, the elastic modulus tends to decrease. ２ The upper limit of the O content is preferably 2% or less, less than 2%, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1% or less, less than 1%, 0.9% or less, 0.8% or less, less than 0.8%, 0.7% or less, less than 0.7%, 0.65% or less, 0.6% or less, 0.55% or less, and particularly preferably 0.5% or less.

[0031] Li ２ O is Cr ２ O ３ -Al ２ O ３ - It is a component that suppresses the precipitation of MgO-based devitrification, and further reduces the viscosity during glass melting, promotes bubble removal, and lowers the molding temperature Tx during glass fiber molding. ２ Since O is expensive, Li ２ If the O content is too high, the production cost will increase. ２ The upper limit of the O content is preferably 2% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, and particularly preferably 0.5% or less. ２The lower limit of the O content is preferably 0% or more, and particularly preferably 0.0001% or more.

[0032] K ２ O is Cr ２ O ３ -Al ２ O ３ - A component that suppresses the precipitation of MgO-based devitrification, and further reduces the viscosity during glass melting, promotes bubble removal, and lowers the molding temperature Tx during glass fiber molding. ２ The lower limit of the O content is preferably 0% or more, 0.001% or more, 0.002% or more, 0.003% or more, 0.004% or more, 0.005% or more, 0.006% or more, 0.007% or more, 0.008% or more, 0.009% or more, or 0.01% or more, particularly preferably more than 0.01%. ２ If the O content is too high, the elastic modulus is likely to decrease. ２ The upper limit of the O content is preferably 5% or less, less than 5%, 4.5% or less, 4% or less, 3.5% or less, 3% or less, less than 3%, 2.9% or less, 2.8% or less, 2.7% or less, 2.6% or less, 2.5% or less, 2.4% or less, 2.3% or less, 2.2% or less, 2.1% or less, 2% or less, less than 2%, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, and particularly preferably less than 1.5%.

[0033] In addition, R ２ The lower limit of the O content is 0% or more, but ２ O ３ -Al ２ O ３ In order to suppress the precipitation of -MgO-based devitrification, reduce the viscosity during glass melting, promote bubble removal, and obtain the effect of lowering the molding temperature Tx during glass fiber molding, the content of R is preferably 0.001% or more, 0.005% or more, 0.01% or more, 0.02% or more, 0.03% or more, 0.04% or more, 0.05% or more, and particularly preferably more than 0.05%. On the other hand, from the viewpoint of suppressing a decrease in the elastic modulus of the glass, R ２The upper limit of the O content is preferably 2% or less, less than 2%, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, less than 1.5%, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1% or less, less than 1%, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, less than 0.5%, 0.4% or less, 0.3% or less, and particularly preferably 0.2% or less. ２ O is Li ２ O, Na ２ O and K ２ It means the total amount of O.

[0034] P ２ O ５ While maintaining Tx, Cr ２ O ３ -Al ２ O ３ -It is a component that can suppress the precipitation of MgO-based devitrification, and therefore efficiently increases the temperature difference ΔTxy. ２ O ５ Since P is a component that does not easily volatilize, it is easy to adjust the content during melting, which in turn makes it easy to adjust the temperature. ２ O ５ The lower limit of the content is 1 ppm or more, 5 ppm or more, 10 ppm or more, 20 ppm or more, 30 ppm or more, 40 ppm or more, 50 ppm or more, 60 ppm or more, 70 ppm or more, 80 ppm or more, 90 ppm or more, 100 ppm or more, 110 ppm or more, 120 ppm or more, 130 ppm or more, 140 ppm or more, 150 ppm or more, 200 ppm or more, 250 ppm or more, 300 ppm or more, 350 ppm or more, 360 ppm or more, 370 ppm or more, 380 ppm or more, 390 ppm or more, 400 ppm or more, preferably more than 400 ppm. ２ O ５ If the content of P is too high, the elastic modulus is likely to decrease. ２ O ５ The upper limit of the content is preferably 2000 ppm or less, 1500 ppm or less, 1400 ppm or less, 1300 ppm or less, 1200 ppm or less, 1100 ppm or less, 1050 ppm or less, and particularly preferably 1000 ppm or less.

[0035] P ２O ５ R against ２ O ratio (R ２ O / P ２ O ５ If R is too low, the molding temperature Tx will be high, which will cause severe damage to the precious metal bushing, increasing the frequency of replacement and increasing production costs. ２ O / P ２ O ５ The lower limit of R is preferably 0.01 or more, 0.05 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, more than 1, 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, more than 1.5, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, and particularly preferably 2 or more. ２ O / P ２ O ５ If is too large, the elastic modulus tends to decrease and ΔTxy tends to become small, so it is preferably 2000 or less, 1000 or less, 200 or less, 100 or less, 50 or less, 20 or less, particularly preferably 10 or less.

[0036] SiO ２ is a main component that forms the glass skeleton structure. It is also a component that improves the mechanical strength and acid resistance of glass. ２ If the content of SiO is too small, the elastic modulus is likely to decrease. ２ The lower limit of the content of SiO is preferably 25% or more, 30% or more, 40% or more, 45% or more, 50% or more, 50.5% or more, 51% or more, 51.5% or more, 52% or more, 52.5% or more, 53% or more, 53.5% or more, 54% or more, 54.5% or more, 55% or more, 55.5% or more, 56% or more, 56.5% or more, 57% or more, 57.5% or more, 58% or more, and particularly preferably more than 58%. ２ If the content of SiO is too high, the viscosity of the molten glass becomes too high, making it difficult to achieve a homogeneous molten state, and as a result, there is a possibility that it becomes difficult to adjust the diameter of the glass fiber. In addition, if the viscosity is high, the energy required to melt the glass increases, and the forming temperature Tx also increases, which causes severe damage to the precious metal bushing, increasing the frequency of replacement and raising the production cost. Therefore, SiO ２The upper limit of the content is preferably 70% or less, 69% or less, 68% or less, 67% or less, 66% or less, 65.5% or less, 65% or less, 64.5% or less, 64% or less, 63.5% or less, or 63% or less, particularly preferably less than 63%.

[0037] Al ２ O ３ Al is a component that enhances the chemical durability and mechanical strength of glass, suppresses the precipitation of crystals and the formation of phase separation in molten glass, and improves the elastic modulus of glass. ２ O ３ If the content of Al is too small, the elastic modulus is likely to decrease. ２ O ３ The lower limit of the Al content is preferably 13% or more, 13.5% or more, 14% or more, 14.5% or more, 15% or more, more than 15%, 15.5% or more, 15.6% or more, 15.7% or more, 15.8% or more, 15.9% or more, 16% or more, 16.5% or more, 16.6% or more, 16.7% or more, 16.8% or more, 16.9% or more, 17% or more, more than 17%, 17.1% or more, 17.2% or more, 17.3% or more, 17.4% or more, 17.5% or more, 17.6% or more, and particularly preferably 17.7% or more. ２ O ３ If the content is too high, Al will be contained in the molten glass. ２ O ３ Mullite (3Al) ２ O ３ 2SiO ２ ) devitrification crystals are likely to occur, and furthermore, the viscosity of the molten glass becomes too high, making it difficult to achieve a homogeneous molten state, which results in a decrease in the dimensional accuracy of the glass fiber diameter. In addition, the energy required to melt the glass increases, and the forming temperature Tx rises, which causes severe damage to the precious metal bushings, increasing the frequency of replacement and increasing production costs. Therefore, Al ２ O ３ The upper limit of the content is preferably 25% or less, less than 25%, 24.5% or less, 23% or less, 22.5% or less, 22% or less, 21.5% or less, 21% or less, 20.5% or less, or 20% or less, particularly preferably less than 20%.

[0038] MgO is a component that acts as a flux to facilitate melting of glass raw materials, reduces the viscosity during glass melting, promotes bubble removal, and lowers the forming temperature Tx. It also improves the elastic modulus and specific elastic modulus of glass. If the MgO content is too low, the viscosity of the molten glass becomes too high, making it difficult to achieve a homogeneous molten state, which tends to reduce the dimensional accuracy of the glass fiber diameter. Furthermore, the forming temperature Tx increases, increasing the energy required to melt the glass, severely damaging the precious metal bushings and requiring more frequent replacement, resulting in higher production costs. Furthermore, the elastic modulus and specific elastic modulus tend to decrease. Therefore, the lower limit of the MgO content is preferably 0.6% or more, 1% or more, 1.2% or more, 1.5% or more, 2% or more, 2.5% or more, 3% or more, 3.5% or more, 4% or more, 4.5% or more, 5% or more, 5.5% or more, 6% or more, 6.5% or more, 7% or more, 7.5% or more, 8% or more, 8.5% or more, 9% or more, 9.5% or more, 10% or more, more than 10%, 10.1% or more, 10.2% or more, 10.3% or more, 10.4% or more, 10.5% or more, 10.6% or more, 10.7% or more, 10.8% or more, 10.9% or more, 11% or more, and particularly more than 11%. On the other hand, if the MgO content is too high, Al ２ O ３ In glass compositions with a high content of ２ O ３ 5SiO ２ ) devitrification crystallization is likely to occur, which may cause clogging of the bushing nozzle during glass fiber molding. Therefore, the upper limit of the MgO content is preferably 25% or less, 24% or less, 23% or less, 22% or less, 21% or less, 20% or less, 19.5% or less, 19% or less, 18.5% or less, 18% or less, 17.5% or less, 17% or less, 16.5% or less, 16% or less, 15.5% or less, 15% or less, 14.5% or less, 14% or less, 13.5% or less, 13.4% or less, 13.3% or less, 13.2% or less, 13.1% or less, 13% or less, less than 13%, 12.9% or less, 12.8% or less, 12.7% or less, 12.6% or less, 12.5% ​​or less, 12.4% or less, 12.3% or less, 12.2% or less, 12.1% or less, and particularly preferably 12% or less.

[0039] Like MgO, CaO acts as a flux that facilitates the melting of glass raw materials. It reduces the viscosity of the glass during melting, promotes bubble removal, and lowers the forming temperature Tx during glass fiber molding. If the CaO content is too low, the viscosity of the molten glass becomes too high, making it difficult to achieve a homogeneous molten state. As a result, the dimensional accuracy of the glass fiber diameter tends to decrease. In addition, the forming temperature Tx increases, increasing the energy required to melt the glass, causing severe damage to the precious metal bushings, increasing their replacement frequency, and increasing production costs. Therefore, the lower limit of the CaO content is preferably 3% or more, 3.5% or more, 4% or more, 4.5% or more, 5% or more, 5.5% or more, 6% or more, 6.5% or more, 7% or more, 7.1% or more, 7.2% or more, 7.3% or more, 7.4% or more, and particularly preferably 7.5% or more. On the other hand, if the CaO content is too high, the molten glass may contain wollastonite (CaO.SiO ２ ) or diopsite (2CaO 2Al ２ O ３ 5SiO ２ ) devitrification crystals are likely to occur, which may cause clogging of the bushing nozzle during glass fiber molding. Furthermore, the elastic modulus and specific elastic modulus tend to be low. Therefore, the upper limit of the CaO content is preferably 15% or less, 14.5% or less, 14% or less, 13.5% or less, 13% or less, 12.9% or less, 12.8% or less, 12.7% or less, 12.6% or less, 12.5% ​​or less, 12.4% or less, 12.3% or less, 12.2% or less, 12.1% or less, and particularly preferably 12% or less.

[0040] If the mass ratio of MgO / CaO is too low, wollastonite (CaO.SiO ２ ) devitrification crystals are likely to occur, which may cause clogging of the bushing nozzle during glass fiber molding. In addition, the molding temperature Tx increases, the energy required for melting the glass increases, and the precious metal bushing is severely damaged, requiring more frequent replacement, which tends to increase production costs. Therefore, the lower limit of MgO / CaO is preferably 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1.0 or more, 1.05 or more, and particularly preferably 1.1 or more. On the other hand, if the MgO / CaO ratio is too large, Al２ O ３ In glass compositions with a high content of ２ O ３ 5SiO ２ ) devitrification crystals are likely to occur, which may cause clogging of the bushing nozzle during glass fiber molding. Furthermore, the molding temperature Tx increases, the energy required to melt the glass increases, and the precious metal bushing is severely damaged, requiring more frequent replacement, which increases production costs. Therefore, the upper limit of MgO / CaO is preferably 4 or less, 3.5 or less, 3 or less, 2.5 or less, 2.4 or less, 2.3 or less, 2.2 or less, 2.1 or less, 2 or less, 1.9 or less, 1.8 or less, 1.7 or less, or 1.65 or less, and particularly preferably less than 1.65.

[0041] B ２ O ３ is SiO ２ Similarly to B, B is a component that forms the framework of the glass network structure, but it also has the function of lowering the viscosity of the glass, accelerating bubble removal, lowering the melting temperature and forming temperature Tx of the glass, and improving the meltability of the glass. ２ O ３ If the content of B is too high, the elastic modulus will decrease and the amount of boron component that evaporates during melting will increase, which may not only corrode the equipment but also pollute the surrounding environment. ２ O ３ The upper limit of the content of is preferably less than 3%, 2.9% or less, 2.8% or less, 2.7% or less, 2.6% or less, 2.5% or less, 2.4% or less, 2.3% or less, 2.2% or less, 2.1% or less, 2%, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, less than 1%, 0.9% or less, 0.8% or less, 0.75% or less, 0.7% or less, 0.65% or less, 0.6% or less, 0.55% or less, 0.5% or less, less than 0.5%, 0.45% or less, 0.45% or less, particularly preferably less than 0.45%. ２ O ３ The lower limit of the content is preferably 0% or more, particularly preferably 0.01% or more.

[0042] TiO ２is a component that improves the elastic modulus of glass. ２ is SiO ２ -Al ２ O ３ In the -MgO composition system, mullite (3Al ２ O ３ 2SiO ２ ) or cordierite (2MgO 2Al ２ O ３ 5SiO ２ Furthermore, since the melting temperature, forming temperature Tx, and viscosity of the glass can be lowered, the elastic modulus of the resulting glass can be maintained while maintaining good productivity. ２ The lower limit of the content of TiO is preferably 0% or more, 0.01% or more, 0.02% or more, 0.03% or more, 0.04% or more, 0.05% or more, 0.06% or more, 0.07% or more, 0.08% or more, 0.09% or more, 0.1% or more, 0.15% or more, 0.2% or more, 0.25% or more, 0.3% or more, 0.35% or more, 0.4% or more, 0.45% or more, 0.5% or more, 0.55% or more, 0.6% or more, 0.65% or more, 0.7% or more, 0.75% or more, 0.8% or more, more than 0.8%, 0.85% or more, 0.9% or more, 0.95% or more, 1% or more, 1.05% or more, 1.10% or more, 1.15% or more, 1.2% or more, and particularly preferably more than 1.2%. ２ Since the raw material is expensive, TiO ２ If the content is too high, the production cost will be high. ２ The upper limit of the content is preferably less than 3%, less than 2.9%, less than 2.8%, less than 2.7%, less than 2.6%, less than 2.5%, less than 2.4%, less than 2.3%, less than 2.2%, less than 2.1%, less than 2%, less than 1.9%, less than 1.8%, or 1.7% or less, particularly preferably less than 1.7%.

[0043] The composition for glass fibers of the present invention may contain the following components in addition to the above components.

[0044] SrO and BaO are components that reduce high-temperature viscosity. However, if the content of SrO and / or BaO is too high, the phase separation of the molten glass tends to increase. The upper limit of the SrO content is preferably 2% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, particularly preferably 0.5% or less. On the other hand, the lower limit of the SrO content is preferably 0% or more, 0.001% or more, 0.002% or more, 0.003% or more, 0.004% or more, 0.005% or more, 0.006% or more, 0.007% or more, 0.008% or more, 0.009% or more, 0.01% or more, and particularly preferably 0.05% or more. The upper limit of the BaO content is preferably 2% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, and particularly preferably 0.5% or less. On the other hand, the lower limit of the BaO content is preferably 0% or more, 0.001% or more, 0.002% or more, 0.003% or more, 0.004% or more, particularly preferably 0.005% or more.

[0045] If the R'O content is too low, the viscosity of the molten glass increases, the forming temperature Tx rises, the energy required to melt the glass increases, and the precious metal bushings are severely damaged, requiring more frequent replacement, and production costs increase. Furthermore, the elastic modulus of the glass is likely to decrease. Therefore, the lower limit of R'O is preferably 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 10% or more, 11% or more, 12% or more, 13% or more, 14% or more, and particularly preferably 15% or more. On the other hand, if the R'O content is too high, cordierite (2MgO.2Al ２ O ３ 5SiO ２ ), wollastonite (CaO.SiO ２), which may cause clogging of the bushing nozzle during glass fiber molding. Therefore, the upper limit of R'O is 40% or less, 39% or less, 38% or less, 37% or less, 36% or less, 35% or less, 34% or less, 33% or less, 32% or less, 31% or less, and preferably 30% or less. Here, R'O is the total amount of MgO, CaO, SrO, and BaO.

[0046] ZrO ２ is TiO ２ It is a component that improves the elastic modulus of glass, similar to the ZrO component. ２ The lower limit of the content of ZrO is preferably 0% or more, 0.001% or more, 0.002% or more, 0.003% or more, 0.004% or more, particularly preferably 0.005% or more. ２ If the content is too high, SiO ２ -Al ２ O ３ In the glass melt of the -MgO composition, mullite (3Al ２ O ３ 2SiO ２ ) or cordierite (2MgO 2Al ２ O ３ 5SiO ２ ) may increase the dehydration temperature. ２ The upper limit of the content is preferably 10% or less, 9.5% or less, 9% or less, 8.5% or less, 8% or less, 7.5% or less, 7% or less, 6.5% or less, 6% or less, 5.9% or less, 5.8% or less, 5.7% or less, 5.6% or less, 5.5% or less, 5.4% or less, 5.3% or less, 5.2% or less, 5.1% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, 0.5% or less, and particularly preferably 0.1% or less.

[0047] Fe ２ O ３ is ZrO ２ , TiO ２ It is a component that improves the elastic modulus of glass, similar to the component Fe. ２ O ３The lower limit of the content of Fe is 0% or more, 0.01% or more, 0.02% or more, 0.03% or more, 0.04% or more, 0.05% or more, 0.06% or more, 0.07% or more, 0.08% or more, 0.09% or more, 0.1% or more, 0.15% or more, 0.2% or more, preferably 0.25% or more. ２ O ３ If the content is too high, Fe in the molten glass ２ O ３ This may cause devitrification crystallization in the system, which may lead to clogging of the bushing nozzle during glass fiber molding. ２ O ３ The upper limit of the content is preferably 3% or less, 2.9% or less, 2.8% or less, 2.7% or less, 2.6% or less, 2.5% or less, 2.4% or less, 2.3% or less, 2.2% or less, 2.1% or less, 2% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, particularly preferably 1.5% or less.

[0048] Y ２ O ３ is a component that improves the elastic modulus of glass, ２ O ３ If the content is too high, the density increases, ２ O ３ The content is preferably 2% or less, 1.5% or less, 1% or less, less than 1%, 0.5% or less, less than 0.5%, 0.1% or less, particularly preferably less than 0.1%.

[0049] In addition, for the purpose of improving clarity, SnO ２ , As ２ O ３ , Sb ２ O ３ , F ２ , CeO ２ , S.O. ３ , Cl ２ The content of each of these elements is preferably 0 to 2%, 0 to 1%, and particularly preferably 0 to 0.8%.

[0050] In order to improve the melting property, elastic modulus, alkali resistance, acid resistance, water resistance, molding temperature, and liquidus temperature, ZnO, MnO, La, etc. are added as components other than those mentioned above. ２ O ３, W.O. ３ , Nb ２ O ５ etc. may be contained up to 2% each as required.

[0051] Furthermore, H ２ , O ２ , CO ２ , CO, H ２ O, He, Ne, Ar, N ２ The glass may contain up to 0.5% of each of these elements. The glass may also contain up to 500 ppm of noble metal elements such as Pt, Rh, and Au.

[0052] A preferred composition example of the glass fiber composition is, in mass %, Cr ２ O ３ 10~6000ppm, SiO ２ 50-70%, Al ２ O ３ 15-20%, MgO 1.2-15%, CaO 3-15%, B ２ O ３ 0 to less than 3%, TiO ２ 0.01 to less than 3%, Na ２ In the composition, the mass ratio is: Al ２ O ３ / Cr ２ O ３ In the composition, the mass ratio of MgO / Cr is preferably more than 150. ２ O ３ In the composition, it is preferable that R ２ O / P ２ O ５ is preferably 0.01 or more.

[0053] Next, the characteristics of the composition for glass fiber of the present invention will be described.

[0054] The glass fiber composition of the present invention preferably has a molding temperature Tx of 1400°C or less, 1390°C or less, 1385°C or less, 1380°C or less, 1375°C or less, 1370°C or less, 1369°C or less, 1368°C or less, 1367°C or less, 1366°C or less, particularly preferably 1365°C or less. If the molding temperature Tx is too high, the energy required to melt the glass increases, causing severe damage to the precious metal bushing, increasing the frequency of replacement and raising production costs. The lower limit of the molding temperature Tx is not particularly limited, but in reality it is 1100°C or more.

[0055] The glass fiber composition of the present invention preferably has a liquidus temperature Ty of 1300°C or less, 1290°C or less, 1285°C or less, 1280°C or less, 1279°C or less, 1278°C or less, 1277°C or less, 1276°C or less, 1275°C or less, 1274°C or less, 1273°C or less, 1272°C or less, 1271°C or less, 1270°C or less, 1269°C or less, 1268°C or less, 1267°C or less, 1266°C or less, and particularly preferably 1265°C or less. If the liquidus temperature Ty is too high, the temperature difference ΔTxy tends to be small, which tends to reduce productivity. The lower limit of the liquidus temperature Ty is not particularly limited, but in reality it is 1000°C or more.

[0056] The glass fiber composition of the present invention preferably has a temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty of 30°C or more, 40°C or more, 45°C or more, 50°C or more, 55°C or more, 60°C or more, 65°C or more, 70°C or more, 75°C or more, 80°C or more, 85°C or more, and particularly preferably more than 85°C. If the temperature difference ΔTxy is too small, devitrified matter that can cause clogging of the bushing nozzle during glass fiber molding is likely to occur, thereby reducing productivity. Note that the upper limit of the temperature difference ΔTxy is not particularly limited, but in reality it is 180°C or less.

[0057] The composition for glass fibers of the present invention preferably has an elastic modulus E of 80 GPa or more, 81 GPa or more, 82 GPa or more, 83 GPa or more, 84 GPa or more, 85 GPa or more, 86 GPa or more, 87 GPa or more, 88 GPa or more, 89 GPa or more, 90 GPa or more, 91 GPa or more, 92 GPa or more, and particularly preferably 93 GPa or more. If the elastic modulus E is too low, it becomes difficult to achieve high functionality (specifically, improved mechanical strength) of the glass fiber-containing composite material. The upper limit of the elastic modulus E is not particularly limited, but in reality it is 150 GPa or less.

[0058] The composition for glass fiber of the present invention has a density ρ of 2 g / cm ３ Above, 2.1g / cm ３ Above, 2.2g / cm ３ Above, 2.3g / cm ３ Above, 2.4g / cm ３ Above, 2.5g / cm ３ Above, 2.55g / cm ３ or more, especially 2.6 g / cm ３ If the density ρ is too low, the elastic modulus E is likely to decrease. On the other hand, if the density ρ is too high, it becomes difficult to achieve high functionality (specifically, weight reduction) of the glass fiber-containing composite material. Therefore, the upper limit of the density ρ is 3 g / cm ３ Below, 2.9g / cm ３ Below, 2.8g / cm ３ Below, especially 2.7 g / cm ３ It is preferable that:

[0059] The glass fiber composition of the present invention preferably has a specific modulus of elasticity calculated by modulus of elasticity E / density ρ of 33 or more, 33.5 or more, 34 or more, 34.5 or more, 35 or more, 35.5 or more, particularly 36 or more. On the other hand, if the specific modulus is too low, it becomes difficult to achieve high functionality of the glass fiber-containing composite material (specifically, achieving both weight reduction and improved mechanical strength). The upper limit of the specific modulus is not particularly limited, but in practice it is 45 or less.

[0060] In order to reduce the viscosity of the melt of the composition for glass fiber of the present invention and promote clarification, the water content β-OH contained in the composition for glass fiber is 0.001 mm －１ More than 0.005mm－１ More than 0.01 mm －１ More than 0.015 mm －１ More than 0.02 mm －１ More than 0.025 mm －１ Above 0.03 mm, especially －１ On the other hand, if the water content β-OH is too high, the generation of bubbles due to fining in the glass melt increases, glass fibers tend to be cut, and productivity tends to decrease. Therefore, the upper limit of the water content β-OH is set to 1 mm －１ Below, 0.95mm －１ Below, 0.90mm －１ Below, 0.85mm －１ Below, 0.8mm －１ Below, 0.75mm －１ Below, 0.7mm －１ Below, 0.65mm －１ Below, 0.6mm －１ Below, especially 0.55 mm －１ It is preferable that:

[0061] Next, the glass fiber and glass fiber-containing composite material of the present invention will be described.

[0062] The glass fiber of the present invention preferably contains 95% or more glass composed of the glass fiber composition described above, calculated as solids. If the glass fiber of the present invention is 95% by mass or more of glass composed of the glass fiber composition described above, with the remainder being an organic substance such as a coating agent, the glass fiber surface is less likely to be scratched during various processing steps, such as the weaving process, and stable strength performance can be maintained. Furthermore, the glass fiber can fully exhibit various physicochemical properties. The content of glass composed of the glass fiber composition in the glass fiber of the present invention is 95 to 100% by mass, calculated as solids, with 95.5 to less than 100% by mass, 96 to 99.99% by mass, and particularly 96.5 to less than 99.99% by mass being preferred. Here, the solids content is calculated by measuring the mass of the glass fiber in a dried state so that the moisture content on the glass surface is less than 0.1% by mass, and then heat-treating it at a high temperature to remove any organic matter applied to the glass fiber surface, and then measuring the mass of the glass alone.

[0063] If the composition for glass fiber is less than 95% by mass in terms of solid content, the organic substance applied to the surface will not significantly improve the performance of protecting the glass fiber, and the amount of organic substance required for application will increase, resulting in increased production costs and making it uneconomical.If the composition for glass fiber is more than 99.99% by mass in terms of solid content, the protective performance of the glass fiber surface may not be fully achieved.

[0064] Furthermore, the glass fiber of the present invention may have a cross-sectional shape perpendicular to the drawing direction during spinning, which may be, in addition to a circular shape, an elliptical, track-shaped, flat, rectangular, cocoon-shaped, polygonal, or other irregular cross-sectional shape.

[0065] The glass fiber of the present invention is preferably in the form of a chopped strand, a yarn, or a roving, which can be used in a variety of applications.

[0066] Here, chopped strands are fibers cut from glass fiber bundles to a predetermined length, yarns are continuous glass fibers that have been twisted, and rovings are multiple strands of glass fiber bundles that have been twisted together.

[0067] The fiber length and fiber diameter of the chopped strands are not limited, and can be selected according to the application. Any method for producing the chopped strands can be employed. The glass strands obtained by spinning molten glass can be directly cut into short fibers. Alternatively, the glass strands obtained by spinning molten glass can be wound into long fibers to form a cake, and then the glass strands can be pulled out from the cake and cut using a cutting device. Any cutting method can be employed. For example, an outer-blade cutting device, an inner-blade cutting device, a hammer mill, or the like can be used. The obtained chopped strands can be randomly layered on a plane and bonded with a binder to form a sheet, or can be randomly accumulated in three dimensions. The chopped strands can also be glass masterbatch (GMB) pellets containing a high content of glass fibers, or LFTP (long fiber reinforced thermoplastic resin) pellets in which the glass fibers are oriented in the same direction.

[0068] The yarn may be any yarn including untwisted yarn, as long as it has a predetermined twist, and there are no particular restrictions on the magnitude or direction of the twist.

[0069] Furthermore, as for the roving, any appearance is acceptable as long as it is made by aligning a plurality of strands, which are glass fiber bundles, into a bundle and winding it into a cylindrical shape, and there are no limitations on the diameter of the wound fibers or the number of strands aligned.

[0070] The glass fiber of the present invention can also be used in the form of a continuous strand mat, bonded mat, cloth, tape, braided fabric, milled fiber, etc. It can also be made into a prepreg impregnated with a resin. Furthermore, the glass fiber can be used in a variety of applications and molding methods, including spray-up, hand lay-up, filament winding, injection molding, centrifugal molding, roller molding, and BMC and SMC methods using a match die.

[0071] The glass fibers of the present invention can be coated with various surface treatment agents to impart desired properties. For example, sizing agents, binders, coupling agents, lubricants, antistatic agents, emulsifiers, emulsion stabilizers, pH adjusters, antifoaming agents, colorants, antioxidants, fungicides, or stabilizers can be applied to the surface of the glass fibers in appropriate amounts, either singly or in any combination. These surface treatment agents or coating agents can be starch-based or plastic-based. For example, sizing agents for FRP can be appropriately selected from acrylic, epoxy, urethane, polyester, vinyl acetate, and vinyl acetate-ethylene copolymers.

[0072] The glass fiber-containing composite material of the present invention is a composite of the above-mentioned glass fiber and a matrix material. The matrix material may be either an organic matrix material or an inorganic matrix material.

[0073] The organic matrix material is typically an organic resin such as a thermoplastic resin or a thermosetting resin, and it is possible to use an appropriate resin alone or in combination depending on the application.

[0074] Examples of the thermoplastic resin include acrylic resins, polyacetal resins, polyamide resins, polyethylene resins, polyethylene terephthalate resins, polycarbonate resins, polystyrene resins, polyphenylene sulfide resins, polybutylene terephthalate resins, polypropylene resins, and polyvinyl chloride resins.

[0075] Examples of the thermosetting resin include epoxy resins, thermosetting modified polyphenylene ether resins, thermosetting polyimide resins, urea resins, allyl resins, silicon resins, benzoxazine resins, phenol resins, unsaturated polyester resins, bismaleimide triazine resins, alkyd resins, furan resins, melamine resins, polyurethane resins, and aniline resins.

[0076] Examples of inorganic matrix materials include concrete and mortar. Concrete is a mixture of cement, sand, gravel, and water, while mortar is a mixture of cement, sand, and water. There are no particular limitations on the mixing ratio of the various components that make up concrete or mortar, or the type of cement. Fly ash, etc., can also be added.

[0077] In addition to glass fibers, glass fiber-containing composite materials can also contain other structural reinforcing materials, such as carbon fibers, ceramic fibers, and bead materials.

[0078] The glass fiber of the present invention can be used alone. For example, in liquid crystal display devices used as display devices for liquid crystal televisions and personal computers, the glass fiber is also suitable for use as a liquid crystal spacer used to maintain the distance between two glass substrates, since the fiber diameter of the glass fiber has stable dimensional accuracy.

[0079] Furthermore, the glass fiber composition and glass fiber of the present invention can be recycled. That is, the glass fiber composition and glass fiber of the present invention can be remelted from an article containing the glass fiber composition and glass fiber, and then molded into a fiber shape or various shapes other than fiber, such as spheres or granules, for use in other applications. For example, they can be used as soil additives, concrete additives or aggregates, asphalt additives, etc.

[0080] Next, the method for producing the glass fiber of the present invention will be described.

[0081] First, a batch of glass raw materials prepared to have the above composition (and properties) is charged into a glass melting furnace, where it is vitrified, melted, and homogenized. The composition is as described above, and therefore will not be described here.

[0082] The molten glass is then spun into glass fibers. Specifically, the molten glass is supplied to a bushing. The molten glass supplied to the bushing is continuously drawn out in the form of filaments from a number of bushing nozzles attached to the bottom surface of the bushing. Various treatment agents are applied to the monofilaments drawn out in this manner, and the monofilaments are bundled together into a predetermined number to obtain glass fibers.

[0083] The glass fibers of the present invention thus formed can be processed into chopped strands, yarns, rovings, etc., and used for various purposes.

[0084] The present invention will be described in detail below based on examples. Note that the following examples are merely illustrative and the present invention is not limited to the following examples in any way.

[0085] (Glass Fiber Composition) Tables 1 to 9 show examples (samples Nos. 1 to 38, 40 to 60) and a comparative example (sample No. 39) of the glass fiber composition of the present invention.

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] Each sample was prepared as follows.

[0096] First, a glass batch was prepared by weighing and mixing predetermined amounts of various glass raw materials using any natural and / or chemical raw materials to obtain the glass composition shown in the table. Next, this glass batch was placed in a platinum-rhodium crucible and heated and melted in an air atmosphere at 1550°C for 5 hours. Note that, in order to obtain a homogeneous molten glass, the molten glass was stirred using a heat-resistant stirring rod during the heating and melting process.

[0097] Thereafter, the molten glass in a homogeneous state was poured into a carbon mold, cast into a predetermined shape, and then slowly cooled to obtain a final glass sample for measurement.

[0098] The physical properties of the obtained glass samples were measured by the following procedures.

[0099] Molding temperature Tx (when the viscosity of the molten glass is 10 ３ The viscosity of the molten glass (temperature corresponding to 10 dPa·s) was measured as follows. After the glass sample was placed in an alumina crucible and heated to a molten state, a viscosity curve was created from viscosity data at each temperature measured based on the platinum sphere pulling method. From the obtained viscosity curve, it was found that the viscosity of the molten glass was 10 ３ The temperature corresponding to dPa·s was calculated by interpolation and used as the molding temperature Tx.

[0100] The liquidus temperature Ty was measured as follows. Glass powder that passed through a 30-mesh (300 μm) standard sieve and remained on a 50-mesh (300 μm) standard sieve was filled into a platinum container to have an appropriate bulk density, placed in an indirectly heated temperature gradient furnace with a maximum temperature set to 1320°C, and heat-treated in an air atmosphere for 16 hours. After allowing the glass sample to cool to room temperature, the glass sample was observed with a polarizing microscope, and the temperature corresponding to the point where crystals (primary phase) began to precipitate was calculated from the temperature gradient in the indirectly heated furnace, and this temperature was taken as the liquidus temperature Ty.

[0101] The temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty was calculated by (molding temperature Tx) - (liquidus temperature Ty).

[0102] The elastic modulus E was determined by annealing a plate-shaped sample having dimensions of 40 mm × 20 mm × 2 mm, which had been polished with a polishing solution containing dispersed No. 1200 alumina powder, in a general annealing furnace, and then measuring both surfaces at room temperature using a free resonance type elastic modulus measuring device (manufactured by Nippon Technoplus Co., Ltd.).

[0103] The density ρ was measured by the well-known Archimedes method using a sample that had been annealed in a general annealing furnace.

[0104] The specific elastic modulus was calculated by (elastic modulus E) / (density ρ).

[0105] As is clear from Tables 1 to 9, the elastic modulus E of Samples No. 1 to 38 and 40 to 60, which are examples, was 90.1 GPa or more, and the temperature difference ΔTxy was 27°C or more.２ O ３ and Al ２ O ３ The influence of Cr on the elastic modulus E and the temperature difference ΔTxy can be considered as follows. For example, when comparing Samples No. 34 and 36, ２ O ３ It can be seen that the elastic modulus E improves as the content of Al increases. ２ O ３ / Cr ２ O ３ As a result, the liquidus temperature Ty increased and the temperature difference ΔTxy decreased. ２ O ３ Content and Al ２ O ３ / Cr ２ O ３ It can be seen that by appropriately adjusting the ratio of the temperature difference ΔTxy, a high elastic modulus E can be achieved while maintaining the temperature difference ΔTxy.

[0106] On the other hand, No. 39, which is a comparative example, is Al ２ O ３ / Cr ２ O ３ is low at 150, and Cr ２ O ３ -Al ２ O ３ As a result, the temperature difference ΔTxy decreased to −11° C.

[0107] (Glass fiber and glass fiber-containing composite material) After melting the glass fiber composition having the composition of Sample No. 1 in Example 1, a bushing device having a platinum nozzle was used to continuously mold a glass monofilament having a diameter of 3 μm. Since fiber breakage was unlikely to occur even during continuous molding, it was possible to obtain a glass monofilament with a stable fiber diameter.

[0108] Next, a suitable amount of a sizing agent containing a silane coupling agent or the like was applied by immersion to the surfaces of the plurality of glass monofilaments obtained by molding using the above-mentioned bushing device, and the resulting mixture was air-dried to obtain glass fibers (glass strands). A plurality of glass fibers were bundled together, impregnated with an organic solvent made of polypropylene resin, and solidified, and then cut to the desired length to obtain LFTP pellets in which the glass fibers were oriented in the same direction.

[0109] By using the LFTP obtained in this way, the glass fiber length in the glass fiber-containing composite material can be increased, so that a high-strength glass fiber-containing composite material can be obtained, and for example, the bending strength of a plate-shaped product can be increased.

[0110] Glass fibers and glass fiber-containing composite materials prepared using the glass fiber composition of the present invention are expected to be used in a variety of applications. For example, in aviation applications, they can be used in aircraft substrates, interior materials, and vibration-proofing materials. In automotive applications, they can be used in vibration-damping reinforcement materials, bumpers, engine undercovers, fenders, roofing materials, bodies, spoilers, muffler filters, dash panels, radiators, timing belts, and the like. In marine applications, they can be used in the bodies of motorboats, yachts, fishing boats, and the like. In construction, civil engineering, and building materials applications, they can be used in decorative walls, illuminated ceilings and lighting covers, facade wallpaper, insect screens, roller blinds, tent membranes, backlit signs, light-transmitting corrugated, flat, and folded sheets, concrete corrosion prevention and reinforcement materials, exterior wall reinforcement materials, waterproof coatings, smoke-proof drapes, nonflammable transparent partitions, projection films, road reinforcement materials, bathtubs, and bathroom and toilet units. In leisure and sports applications, they can be used in fishing rods, tennis rackets, golf clubs, skis, helmets, and the like. In electronic equipment-related applications, it can be used for printed wiring boards, insulating boards, terminal boards, IC substrates, electronic equipment housing materials, electronic component packaging materials, optical equipment housing materials, optical component packaging materials, insulating supports, etc. In industrial facility-related applications, it can be used for wind turbine blades, glass filter bags, non-combustible heat insulating material outer covering materials, resinoid grinding wheel reinforcing materials, aluminum filtration filters, etc. In agricultural applications, it can be used for vinyl greenhouses, agricultural poles, silo tanks, etc.

Claims

1. Cr by mass% ２ O ３ Contains 10 ppm or more and, by mass ratio, Al ２ O ３ / Cr ２ O ３ A composition for glass fibers, characterized in that the molecular weight is greater than 150.

2. Cr by mass% ２ O ３ 2. The composition for glass fibers according to claim 1, wherein the composition contains 10 to 6,000 ppm.

3. Mass ratio: MgO / Cr ２ O ３ 3. The composition for glass fibers according to claim 1, wherein the molecular weight is 20 or more.

4. Mass % P ２ O ５ Contains 10 to 1000 ppm and has a mass ratio of R ２ O / P ２ O ５ (R ２ O is Li ２ O, Na ２ O and K ２ 3. The glass fiber composition according to claim 1, wherein the total amount of SiO and O is 0.01 or more.

5. Sodium by mass ２ 5. The glass fiber composition of claim 4 containing less than 0.8% O.

6. SiO ２ 25-70%, Al ２ O ３ 13-25%, MgO 0.6-25%, CaO 3-15%, B ２ O ３ 3. The glass fiber composition according to claim 1, wherein the content is 0 to less than 3%.

7. Cr, by mass% ２ O ３ 10~6000ppm, SiO ２ 50-70%, Al ２ O ３ More than 15 to 20%, MgO 1.2 to 15%, CaO 3 to 15%, B ２ O ３ 0 to less than 3%, TiO ２ 0.01 to less than 3%, Na ２ A composition for glass fibers comprising less than 0.8% O.

8. By mass ratio, Al ２ O ３ / Cr ２ O ３ The glass fiber composition according to claim 7, characterized in that the .lambda. is greater than 150.

9. Mass ratio: MgO / Cr ２ O ３ 9. The composition for glass fibers according to claim 7, wherein the molecular weight is 20 or more.

10. Mass ratio, R ２ O / P ２ O ５ The composition for glass fibers according to claim 7 or 8, wherein is 0.01 or more.

11. A composition for glass fibers according to claim 1 or 2, characterized in that the molding temperature Tx is 1,400° C. or lower.

12. The glass fiber composition according to claim 1 or 2, characterized in that the temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty is 30° C. or more.

13. A composition for glass fibers according to claim 1 or 2, characterized in that the elastic modulus E is 80 GPa or more.

14. A glass fiber comprising the glass fiber composition according to claim 1 or 2.

15. A glass fiber-containing composite material, characterized in that it is a composite of the glass fiber according to claim 14 and a matrix material.

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