Composition for glass fibers

Abstract

To provide, at low cost, a glass composition that has a high elastic modulus and features good productivity.SOLUTION: A composition for glass fibers contains, by mass%, SiO2 of 40-60%, Al2O3 of 10-30%, B2O3 of 0-10%, MgO of 5-20%, CaO of 5-20%, SrO of 0-10%, and BaO of 0-10%.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Glass fibers (also called glass fibers or glass filaments) are manufactured by continuously forming (spinning) molten glass into fibers using a forming device called a bushing device, which generally has a roughly rectangular planar shape. The bushing device is disposed at the bottom of a pot-shaped container that has a temporary retention function for molten glass. The bushing device is made of a heat-resistant metal material such as platinum, and is equipped with a number of nozzles (or orifices) at its bottom. In this bushing device, the molten glass at the nozzle tip is heated to an optimum temperature for forming, specifically, when the high-temperature viscosity of the molten glass is 10 3 The temperature is controlled so that the temperature corresponds to the viscosity of the glass in dPa·s. The molten glass is then continuously drawn out from the nozzle, rapidly cooled, and formed into glass fibers.

[0003] When forming glass fibers, the liquidus temperature Ty of the molten glass is 10°C, and the forming temperature Tx of the glass is 10°C. 3 If the temperature exceeds the melting point (the temperature corresponding to dPa·s), crystals that cause devitrification are likely to precipitate in the molten glass near the nozzle. This results in clogging of the nozzle and thread breakage, also known as breakage. For this reason, the liquidus temperature Ty of the molten glass must be below the forming temperature Tx (i.e., the temperature difference ΔTxy = Tx - Ty ≧ 0). Furthermore, a larger temperature difference ΔTxy is preferable. 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 higher manufacturing costs and shorter lifespans of auxiliary equipment such as bushings. Therefore, it is preferable to lower the forming temperature Tx.

[0004] Thus, in the production of glass fibers, it is extremely important to control the forming temperature Tx and the temperature difference ΔTxy. At the same time, there is a demand for glass fibers with superior elastic modulus and specific modulus (specifically, Young's modulus and specific Young's modulus) due to the need for higher performance glass fiber-containing composite materials. S-glass, which is made of a glass composition containing SiO2, Al2O3, and MgO, is known as a glass for glass fibers with such properties. However, S-glass has a high forming temperature Tx and a high liquidus temperature Ty, resulting in a small temperature difference ΔTxy, which has led to productivity problems.

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

[0006] [Patent Document 1] Patent No. 7263507 Summary of the Invention [Problem to be solved by the invention]

[0007] The glass composition disclosed in Patent Document 1 has a high Young's modulus, a low fiberization temperature (i.e., forming temperature Tx), and a large ΔT (temperature difference ΔTxy). However, since it contains a large amount of rare earth oxides, exceeding 8 mass%, the production cost increases and there is a risk of instability in the supply of raw materials.

[0008] An object of the present invention is to provide a glass fiber composition that has a high elastic modulus and good productivity at low cost. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the above problems can be solved by a glass composition having a predetermined composition, and propose this as the present invention. That is, the composition for glass fiber of the present invention is characterized by containing, by mass%, 40-60% of SiO2, 10-30% of Al2O3, 0-10% of BO3, 5-20% of MgO, 5-20% of CaO, 0-10% of SrO, and 0-10% of BaO.

[0010] The composition for glass fibers of the present invention preferably contains, in mass %, 0.01 to 10% of B2O3.

[0011] The composition for glass fibers of the present invention preferably contains 40 to 55% by mass of SiO2.

[0012] The composition for glass fibers of the present invention preferably contains, in mass %, 40 to 55% of SiO2, 20 to 30% of Al2O3, and 0.01 to 10% of B2O3.

[0013] The composition for glass fibers of the present invention preferably has a SiO2 / Al2O3 mass ratio of 1.35 to 4.

[0014] In the composition for glass fibers of the present invention, the mass ratio of MgO / CaO is preferably 0.5 to 3.

[0015] The composition for glass fibers of the present invention preferably contains, by mass %, 0.001% or more of ZrO2.

[0016] The composition for glass fibers of the present invention preferably has a rare earth element oxide content of 8% by mass or less.

[0017] The composition for glass fibers of the present invention preferably contains, in mass %, 50 to 55% of SiO2, 20 to 24% of Al2O3, 0.01 to 2.5% of B2O3, 8 to 20% of MgO, and 5 to 10% of CaO.

[0018] The composition for glass fibers of the present invention preferably contains, in mass %, 1% or less of Li2O+Na2O+K2O.

[0019] The composition for glass fiber of the present invention preferably has a Young's modulus of 90 GPa or more, which makes it possible to obtain a glass fiber-containing composite material with small distortion to stress and high physical strength.

[0020] The composition for glass fiber of the present invention is preferably formed at a temperature of 1,400°C or less. This allows fiberization at a low temperature, which can extend the life of forming equipment such as bushings and reduce production costs. The forming temperature is set at a temperature at which the high-temperature viscosity of the molten glass is 10 3 This is the temperature equivalent to dPa·s.

[0021] The glass fiber composition of the present invention preferably has a temperature difference ΔTxy between the molding temperature and the liquidus temperature of 0°C or more. This makes it possible to improve productivity. 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 50 mesh sieve (sieve opening 300 μm) in a platinum boat and holding it in a temperature gradient furnace for 24 hours, and then measuring the temperature at which crystals (primary phase) precipitate.

[0022] The glass fiber composition of the present invention has a density of 2.75 g / cm 3 It is preferable that the glass fiber-containing composite material is lighter in weight.

[0023] The glass fiber of the present invention is characterized by containing the above-mentioned composition for glass fiber.

[0024] The glass fiber-containing composite material of the present invention is characterized by being a composite of the above-mentioned glass fiber and a resin.

[0025] The glass composition of the present invention is characterized by containing, in mass %, 40-60% of SiO2, 10-30% of Al2O3, 0-10% of B2O3, 5-20% of MgO, 5-20% of CaO, 0-10% of SrO, and 0-10% of BaO. [Effects of the Invention]

[0026] According to the present invention, a composition for glass fibers having a high elastic modulus and good productivity can be provided at low cost. DETAILED DESCRIPTION OF THE INVENTION

[0027] The glass fiber composition of the present invention is characterized by containing, by mass%, 40-60% SiO2, 10-30% Al2O3, 0-10% BO3, 5-20% MgO, 5-20% CaO, 0-10% SrO, and 0-10% BaO. The reasons for limiting the glass composition as above are as follows. In the following explanation of the content of each component, "%" means "% by mass" unless otherwise specified.

[0028] SiO2 is a major component that forms the glass skeleton structure. It also improves the mechanical strength and acid resistance of glass. If the SiO2 content is too low, the elastic modulus will be low, making it difficult to obtain sufficient mechanical strength. Furthermore, acid resistance will be easily reduced. Therefore, the lower limit of the SiO2 content is preferably 40% or more, 45% or more, 47% or more, 48% or more, 49% 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, and particularly 53.5% or more. On the other hand, if the SiO2 content is too high, the viscosity of the molten glass will be too high, making it difficult to achieve a homogeneous molten state, which may result in difficulty in adjusting the glass fiber diameter. Furthermore, high viscosity increases the energy required to melt the glass, raises the molding temperature, and severely damages the bushing, requiring more frequent replacement, resulting in higher production costs. Therefore, the upper limit of the SiO2 content is preferably 60% or less, 59.5% or less, 59% or less, 58.5% or less, 58% or less, 57.5% or less, 57% or less, 56.5% or less, 56% or less, 55.5% or less, 55% or less, 54.5% or less, and particularly preferably 54% or less.

[0029] Al2O3 is a component that enhances the chemical durability and mechanical strength of glass, suppresses the occurrence of devitrification crystallization and phase separation in molten glass, and improves the elastic modulus of glass. If the Al2O3 content is too low, the elastic modulus will be low, making it difficult to obtain sufficient mechanical strength. Therefore, the lower limit of the Al2O3 content is preferably 10% or more, 13% or more, 15% or more, 16% or more, 17% or more, 17.5% or more, 18% or more, 18.5% or more, 19% or more, 19.5% or more, 20% or more, 20.5% or more, 21% or more, 21.5% or more, 22% or more, and particularly preferably 22.5% or more. On the other hand, if the Al2O3 content is too high, devitrification crystals such as mullite (3Al2O3·2SiO2), which is primarily composed of Al2O3, or cordierite (2MgO·2Al2O3·5SiO2), which is primarily composed of Al2O3 and MgO, are likely to occur in the molten glass. Furthermore, 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. Furthermore, the energy required to melt the glass increases, the molding temperature rises, and bushing damage becomes severe, requiring more frequent replacement, resulting in higher production costs. Therefore, the upper limit of the Al2O3 content is preferably 30% or less, 29% or less, 28% or less, 27% or less, 26% or less, 25% or less, 24.5% or less, 24% or less, 23.5% or less, and particularly preferably less than 23%.

[0030] Furthermore, if the SiO2 / Al2O3 mass ratio is too small, devitrification crystals are more likely to occur, reducing productivity. Furthermore, the molding temperature 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. On the other hand, if the SiO2 / Al2O3 ratio is too large, the elastic modulus decreases, making it difficult to obtain sufficient mechanical strength. Furthermore, the viscosity of the molten glass becomes too high, making it difficult to achieve a homogeneous molten state, resulting in reduced dimensional accuracy of the glass fiber diameter. Therefore, the lower limit of the SiO2 / Al2O3 ratio is preferably 1.35 or more, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, 2 or more, 2.1 or more, 2.2 or more, and particularly preferably 2.3 or more, and the upper limit of the SiO2 / Al2O3 ratio is preferably 4 or less, 3.9 or less, 3.8 or less, 3.7 or less, 3.6 or less, 3.5 or less, 3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, 3 or less, 2.9 or less, 2.8 or less, 2.7 or less, 2.6 or less, and particularly preferably 2.5 or less. Note that "SiO2 / Al2O3" means the value obtained by dividing the SiO2 content by the Al2O3 content.

[0031] Like SiO2, B2O3 is a component that forms the framework of the glass network structure. It also reduces the viscosity of glass, promoting bubble removal, lowering the melting and forming temperatures of glass, and improving the meltability of glass. The upper limit of B2O3 is preferably 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3.5% or less, 3% or less, or 2.5% or less, and particularly preferably 2% or less. Too high a B2O3 content can reduce the elastic modulus and increase the amount of boron vaporized during melting, potentially corroding equipment and polluting the surrounding environment. The lower limit of B2O3 is preferably 0% or more, 0.01% or more, 0.05% or more, 0.07% or more, 0.08% or more, or 0.09% or more, and particularly preferably 0.1% or more.

[0032] MgO is a component that functions as a flux to facilitate the melting of glass raw materials, reduces the viscosity during glass melting, promotes bubble removal, and lowers the molding temperature. It also improves the mechanical strength of glass and improves the elastic modulus and specific modulus. 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, resulting in a decrease in the dimensional accuracy of the glass fiber diameter. Furthermore, the molding temperature increases, increasing the energy required to melt the glass, severely damaging the bushing and requiring more frequent replacement, which increases production costs. Furthermore, the elastic modulus and specific modulus decrease, making it difficult to obtain sufficient mechanical strength. Therefore, the lower limit of the MgO content is preferably 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 10% or more, 10.5% or more, 11% or more, 11.5% or more, and particularly preferably 12% or more. On the other hand, if the MgO content is too high, particularly in a glass composition with a high Al2O3 content, devitrification crystals of cordierite (2MgO 2Al2O3 5SiO2) are likely to occur in the molten glass, which may cause clogging of the bushing nozzle during glass fiber molding. Therefore, the upper limit of the MgO content is preferably 20% or less, 19% or less, 18% or less, 17% or less, 16% or less, 15% or less, 14.5% or less, and particularly preferably 14% or less.

[0033] Like MgO, CaO functions as a flux, facilitating the melting of glass raw materials. It reduces the viscosity of the glass during melting, promoting bubble removal, and lowering the molding temperature 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, resulting in a decrease in the dimensional accuracy of the glass fiber diameter. Furthermore, the molding temperature increases, increasing the energy required to melt the glass, causing severe damage to the bushing, increasing the frequency of replacement, and increasing production costs. Therefore, the lower limit of the CaO content is preferably 5% or more, 6% or more, 6.5% or more, 7% or more, 7.5% or more, or 8% or more, and particularly preferably 8.5% or more. On the other hand, if the CaO content is too high, devitrification crystals of wollastonite (CaO·SiO2) are likely to form in the molten glass, which may cause clogging of the bushing nozzle during glass fiber molding. Furthermore, the elastic modulus and specific modulus decrease, making it difficult to obtain sufficient mechanical strength. Therefore, the upper limit of the CaO content is preferably 20% or less, 17% or less, 16% or less, 15% or less, 14% or less, 13% or less, 12.5% ​​or less, 12% or less, 11.5% or less, 11% or less, 10.5% or less, particularly preferably 10% or less.

[0034] Furthermore, if the MgO / CaO mass ratio is too low, devitrification crystals of wollastonite (CaO·SiO2) are likely to form in the molten glass, which may cause clogging of the bushing nozzle during glass fiber molding. Furthermore, the molding temperature increases, increasing the energy required to melt the glass, which causes severe damage to the bushing, requiring more frequent replacement and increasing production costs. Therefore, the MgO / CaO ratio is preferably 0.5 or more, 0.7 or more, 0.8 or more, 0.9 or more, 1 or more, 1.1 or more, 1.15 or more, 1.2 or more, 1.25 or more, and particularly 1.3 or more. On the other hand, if the MgO / CaO ratio is too high, especially in glass compositions with a high Al2O3 content, devitrification crystals of cordierite (2MgO·2Al2O3·5SiO2) are likely to form in the molten glass, which may cause clogging of the bushing nozzle during glass fiber molding. Furthermore, the molding temperature increases, the energy required to melt the glass increases, and the bushing is severely damaged, requiring more frequent replacement, which increases production costs. Therefore, the MgO / CaO ratio is preferably 3 or less, 2.5 or less, 2.3 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, 1.55 or less, and particularly preferably 1.5 or less. "MgO / CaO" means the value obtained by dividing the MgO content by the CaO content.

[0035] SrO and BaO are components that reduce high-temperature viscosity. The SrO content is preferably 0 to 10%, 0 to 9%, 0 to 8%, 0 to 7%, 0 to 6%, 0 to 5%, 0 to 4%, 0 to 3%, 0 to 2%, 0 to 1%, 0 to 1%, 0 to 1%, 0 to 0.9%, 0 to 0.8%, 0 to 0.7%, 0 to 0.6%, 0 to 0.5%, 0.001 to 0.5%, 0.002 to 0.5%, 0.003 to 0.5%, 0.004 to 0.5%, 0.005 to 0.5%, 0.006 to 0.5%, 0.007 to 0.5%, 0.008 to 0.5%, 0.009 to 0.5%, 0.01 to 0.5%, and particularly preferably 0.05 to 0.5%. The BaO content is preferably 0 to 10%, 0 to 9%, 0 to 8%, 0 to 7%, 0 to 6%, 0 to 5%, 0 to 4%, 0 to 3%, 0 to 2%, 0 to 1%, 0 to 1%, 0 to 1%, 0 to 0.9%, 0 to 0.8%, 0 to 0.7%, 0 to 0.6%, 0 to 0.5%, 0.001 to 0.5%, 0.002 to 0.5%, 0.003 to 0.5%, 0.004 to 0.5%, 0.005 to 0.5%, 0.006 to 0.5%, 0.007 to 0.5%, 0.008 to 0.5%, 0.009 to 0.5%, 0.01 to 0.5%, and particularly preferably 0.05 to 0.5%. If the SrO and / or BaO content is too high, the phase separation of the molten glass tends to increase.

[0036] The ratio of MgO+CaO+SrO+BaO is preferably 10-40%, 10-38%, 12-35%, 15-30%, 18-28%, 19-25%, and particularly preferably 20-24%. If the ratio of MgO+CaO+SrO+BaO is too low, the viscosity of the molten glass becomes too high, making it difficult to achieve a homogeneous molten state, resulting in a decrease in the dimensional accuracy of the glass fiber diameter. Furthermore, the molding temperature increases, increasing the energy required to melt the glass, causing severe damage to the bushing, requiring more frequent replacement, and increasing production costs. Furthermore, the elastic modulus decreases, making it difficult to obtain sufficient mechanical strength. On the other hand, if the ratio of MgO+CaO+SrO+BaO is too high, devitrified crystals such as cordierite (2MgO·2Al2O3·5SiO2) and wollastonite (CaO·SiO2) are likely to form in the molten glass, which may cause clogging of the bushing nozzle during glass fiber molding. Here, "MgO+CaO+SrO+BaO" means the total amount of MgO, CaO, SrO and BaO.

[0037] In addition to the above components, the composition for glass fibers of the present invention may contain the following components in the glass composition.

[0038] TiO2 is a component that improves the elastic modulus of glass, and in the SiO2-Al2O3-MgO composition system, it works to lower the quenching temperature of mullite (3Al2O3·2SiO2) or cordierite (2MgO·2Al2O3·5SiO2). Furthermore, it reduces the viscosity of glass, allowing for lower melting and molding temperatures, thereby maintaining the elastic modulus of the resulting glass while maintaining good productivity. The lower limit of the TiO2 content 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, and particularly preferably 0.7% or more. Note that a relatively low SiO2 content (e.g., less than 57%) and a relatively high TiO2 content (e.g., 0.5% or more) are preferred, as this facilitates achieving both a low liquidus temperature and a high elastic modulus. On the other hand, if the TiO2 content is too high, TiO2-based devitrification crystals are likely to form in the molten glass, which may cause clogging of the bushing nozzle during glass fiber molding. Therefore, the upper limit of the TiO2 content is preferably 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, 1.9% or less, 1.8% or less, or 1.7% or less, and particularly preferably less than 1.7% or 1% or less.

[0039] ZrO2, like TiO2, is a component that improves the elastic modulus of glass. The lower limit of the ZrO2 content is preferably 0% or more, 0.001% or more, 0.002% or more, 0.003% or more, or 0.004% or more, and particularly preferably 0.005% or more. On the other hand, if the ZrO2 content is too high, it may increase the quenching temperature of mullite (3Al2O3·2SiO2) or cordierite (2MgO·2Al2O3·5SiO2) in glasses with a SiO2-Al2O3-MgO composition. Therefore, the upper limit of the ZrO2 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, and particularly preferably 1% or less.

[0040] Like ZrO2 and TiO2, Fe2O3 is a component that improves the elastic modulus of glass, but if the Fe2O3 content is too high, Fe2O3-based devitrification crystals are more likely to form in the molten glass, which may cause clogging of the bushing nozzle during glass fiber molding. For this reason, the Fe2O3 content is preferably 0 to 3%, 0 to 2.9%, 0 to 2.8%, 0 to 2.7%, 0 to 2.6%, 0 to 2.5%, 0 to 2.4%, 0 to 2.3%, 0 to 2.2%, 0 to 2.1%, 0 to 2%, 0.01 to 2%, 0.01 to 1%, and particularly 0.01 to 0.5%.

[0041] P2O5 is a component that suppresses crystallization of devitrification and lowers the liquidus temperature. The P2O5 content is preferably 0 to less than 2.0%, 0 to 1.5%, 0 to 1%, 0 to 0.7%, and particularly preferably 0 to 0.4%. If the P2O5 content is too high, the elastic modulus decreases, making it difficult to obtain sufficient mechanical strength.

[0042] Li2O, Na2O, and K2O are components that reduce the viscosity of glass during melting, promote bubble removal, and lower the molding temperature of glass fibers. However, if the content of these components is too high, the elastic modulus decreases, making it difficult to obtain sufficient mechanical strength. The lower limit of the content of Li2O + Na2O + K2O 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, and particularly preferably greater than 0.01%. On the other hand, the upper limit of the content of Li2O + Na2O + K2O is preferably 1% or less, 0.8% or less, 0.6% or less, 0.4% or less, 0.2% or less, or 0.1% or less, and particularly preferably less than 0.1%. The lower limit of the content of each of the components Li2O, Na2O, and K2O 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, and particularly preferably more than 0.01%. The upper limit is preferably 1% or less, 0.8% or less, 0.6% or less, 0.4% or less, 0.2% or less, or 0.1% or less, and particularly preferably less than 0.1%.

[0043] Furthermore, for the purpose of improving clarity, any one or more elements selected from SnO2, As2O3, Sb2O3, CeO2, SO3, F, and Cl may be added. The respective contents are preferably 0 to 2%, 0 to 1%, 0 to 0.5%, 0 to 0.4%, or 0 to 0.3%, and particularly preferably 0.01 to 0.3%.

[0044] In order to improve meltability, elastic modulus, alkali resistance, acid resistance, water resistance, molding temperature, or liquidus temperature, other components besides those mentioned above, such as ZnO, Cr2O3, MnO, MoO, La2O3, WO3, and Nb2O5, may be added in appropriate amounts as needed, up to 2% each. However, in the glass composition of the present invention, a high Cr2O3 content tends to cause the precipitation of devitrification crystals. Therefore, from the viewpoint of improving the liquidus temperature, the Cr2O3 content is preferably 0.1% or less, less than 0.1%, 0.05% or less, and particularly 0.01% or less.

[0045] Y2O3 is a component that improves the elastic modulus of glass, but if the Y2O3 content is too high, the density increases and the manufacturing costs become higher. Therefore, the Y2O3 content is preferably 2% or less, 1.5% or less, 1% or less, less than 1%, 0.5% or less, less than 0.5%, or 0.1% or less, particularly less than 0.1%, and most preferably zero.

[0046] Inclusion of rare earth element oxides (Y2O3, La2O3, CeO2, etc.) increases the density and manufacturing costs. Therefore, from the viewpoint of reducing the density of the glass and reducing manufacturing costs, the content (total amount) of rare earth element oxides contained in the glass is preferably 8% or less, 5% or less, 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, and particularly less than 0.1%, and it is most preferable that no rare earth element oxides are contained.

[0047] The glass may contain up to 0.5% of each of H2, O2, CO2, CO, H2O, He, Ne, Ar, N2, etc. Furthermore, the glass may contain up to 500 ppm of precious metal elements such as Pt, Rh, and Au.

[0048] The properties of the composition for glass fiber of the present invention will be described below.

[0049] The glass fiber composition of the present invention preferably has a molding temperature Tx of 1400°C or less, 1390°C or less, 1380°C or less, 1370°C or less, 1360°C or less, 1350°C or less, 1340°C or less, 1330°C or less, 1320°C or less, 1310°C or less, 1300°C or less, and particularly preferably 1290°C or less. If the molding temperature Tx is too high, the energy required to melt the glass increases, causing severe damage to the 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.

[0050] The glass fiber composition of the present invention preferably has a liquidus temperature Ty of 1340°C or less, 1320°C or less, 1300°C or less, 1290°C or less, 1280°C or less, 1275°C or less, 1270°C or less, and particularly preferably 1265°C or less. If the liquidus temperature Ty is too high, the temperature difference ΔTxy (=Tx-Ty) from the molding temperature Tx tends to become small, which tends to reduce productivity. There is no particular restriction on the lower limit of the liquidus temperature Ty, but in reality it is 1000°C or more.

[0051] 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 0°C or more, 10°C or more, 20°C or more, 30°C or more, 40°C or more, 45°C or more, and particularly 50°C or more. If the temperature difference ΔTxy is too small, devitrification crystals that cause clogging of the bushing nozzle during glass fiber molding are more likely to occur, resulting in reduced productivity. Note that the upper limit of the temperature difference ΔTxy is not particularly limited, but in practice it is 180°C or less.

[0052] The glass fiber composition of the present invention preferably has a liquidus viscosity log η (logarithm of viscosity at liquidus temperature Ty) of 2.5 or more, 2.6 or more, 2.7 or more, 2.8 or more, 2.9 or more, particularly 3 or more. If the liquidus viscosity log η is too small, productivity tends to deteriorate. There is no particular upper limit for the liquidus viscosity log η, but if it is too large, there is a risk that it will limit the improvement of other properties, particularly Young's modulus. Therefore, it is preferably 4.5 or less, 4.2 or less, 4 or less, 3.8 or less, particularly 3.6 or less.

[0053] The glass fiber composition of the present invention preferably has a Young's modulus, which is one type of elastic modulus, of 90 GPa or more, 91 GPa or more, 92 GPa or more, 93 GPa or more, 94 GPa or more, 94.5 GPa or more, 95 GPa or more, 95.5 GPa or more, and particularly 96 GPa or more. If the Young's modulus is too low, it becomes difficult to achieve high functionality in the glass fiber-containing composite material. The upper limit of the Young's modulus is not particularly limited, but in practice it is 150 GPa or less.

[0054] The composition for glass fibers of the present invention preferably has a modulus of rigidity of 36 GPa or more, 37 GPa or more, 38 GPa or more, particularly 38.5 GPa or more. If the modulus of rigidity is too low, it becomes difficult to achieve high performance in the glass fiber-containing composite material. The upper limit of the modulus of rigidity is not particularly limited, but in practice it is 50 GPa or less.

[0055] The glass fiber composition of the present invention preferably has a Poisson's ratio of 0.20 to 0.30, 0.21 to 0.29, 0.22 to 0.28, or 0.23 to 0.27, particularly preferably 0.23 to 0.26. When the Poisson's ratio is within this range, the composition is as easy to handle as existing high-elasticity glass fibers, and the desired strength of the glass fiber-containing composite material is easily obtained.

[0056] The composition for glass fiber of the present invention has a thermal expansion coefficient of 40×10 in the temperature range of 30 to 380°C. -7 / ℃~60×10 -7 / ℃, 43×10 -7 / ℃~55×10 -7 / ℃, 44×10 -7 / ℃~52×10 -7 / ℃, especially 45×10 -7 / ℃~50×10 -7 / °C. If the thermal expansion coefficient in the temperature range of 30 to 380°C is within this range, the glass fiber can be handled as easily as existing high-elastic modulus glass fibers in processes that cause temperature changes, and the desired strength of the glass fiber-containing composite material can be easily obtained.

[0057] The composition for glass fiber of the present invention has a density ρ of 2 g / cm 3 More than 2.1g / cm 3 More than 2.2g / cm 3 More than 2.3g / cm 3 More than 2.4g / cm 3 More than 2.5g / cm 3 More than 2.55g / cm 3 More than 2.6g / cm 3 Above, especially 2.65g / cm 3It is preferable that the density ρ is equal to or greater than 3 g / cm. If the density ρ is too low, the elastic modulus will be low, making it difficult to obtain sufficient mechanical strength. On the other hand, if the density ρ is too high, the specific elastic modulus (specific Young's modulus) will tend to be small, making it difficult to achieve high functionality in the glass fiber-containing composite material. For this reason, the upper limit of the density ρ is 3 g / cm. 3 Below, 2.9g / cm 3 Below, 2.8g / cm 3 Below 2.75g / cm 3 Below, especially 2.7g / cm 3 It is preferable that:

[0058] The composition for glass fiber of the present invention has a specific Young's modulus (unit: GPa / (g / cm)) calculated by dividing the Young's modulus by the density. 3 )) is preferably 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. If the specific Young's modulus is too low, it becomes difficult to achieve high performance in the glass fiber-containing composite material. The upper limit of the specific Young's modulus is not particularly limited, but in reality it is 45 or less.

[0059] Next, the method for producing the glass fiber composition of the present invention, and the glass fiber and glass fiber-containing composite material of the present invention will be described.

[0060] First, a raw material batch prepared to obtain glass of the above composition is placed in a glass melting furnace and melted at 1400 to 1700°C to homogenize it. Cullet may be used as part or all of the glass raw material. 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 multiple 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.

[0061] The melting method is preferably a method in which any one of the following melting methods is used, or a combination of two or more of them: a flame melting method using a burner or the like, an electric melting method using electric heating, a melting method using laser irradiation, a melting method using plasma, a liquid phase synthesis method, and a vapor phase synthesis method.

[0062] The cross-sectional shape of the glass fiber of the present invention may be a circular shape, or may be an irregular cross-sectional shape such as an ellipse, a track shape, a flat shape, a rectangle, a cocoon shape, or a polygon.

[0063] 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.

[0064] 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.

[0065] The chopped strands are not limited in fiber length or fiber diameter, and can be selected according to the application. Any method for producing chopped strands can be used. They can be made into short fibers directly from the melting process, or they can be wound into long fibers and then cut using a cutting device depending on the application. Any cutting method can be used. For example, an outer-blade cutting device, an inner-blade cutting device, a hammer mill, or the like can be used. The assembly form of the chopped strands is also not particularly limited. Chopped strands of an appropriate length can be randomly layered on a plane and bonded with a specific binder to form a mat, or they can be accumulated randomly in three dimensions to form a bulk. Glass masterbatch (GMB) pellets (also called resin columns, LFTP, etc.) containing a high content of glass fibers can also be used.

[0066] 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.

[0067] 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.

[0068] 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 resin-impregnated prepreg. 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.

[0069] 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, antifungal agents, 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 coatings 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.

[0070] The glass fiber of the present invention contains 95% or more glass composed of the glass fiber composition described above, calculated as solid content. 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 solid content, and is preferably 95.5 to less than 100% by mass, 96 to 99.99% by mass, and particularly preferably 96.5 to less than 99.99% by mass. Here, the solid content value is calculated by measuring the mass of the glass fiber in a dried state so that the moisture content on the surface is less than 0.1% by mass, further heat-treating the glass fiber at a high temperature to remove any organic matter applied to the surface, and then measuring the mass, and calculating the ratio to the measured value before heat treatment.

[0071] Even if the composition for glass fibers is less than 95% by mass in terms of solid content, the organic substance applied to the surface does not significantly improve the performance of protecting the glass fibers, and the amount of organic substance required for application increases, which increases production costs and is not economical. Also, if the composition for glass fibers exceeds 99.99% by mass in terms of solid content, the protective performance of the glass fiber surface may not be fully achieved.

[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] Examples of organic matrix materials include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins 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. Examples of thermosetting resins include epoxy resins, thermosetting modified polyphenylene ether resins, thermosetting polyimide resins, urea resins, allyl resins, silicon resins, benzoxazine resins, phenolic resins, unsaturated polyester resins, bismaleimide triazine resins, alkyd resins, furan resins, melamine resins, polyurethane resins, and aniline resins. These resins can be used alone or in combination depending on the application. Other structural reinforcing materials, such as carbon fiber, ceramic fiber, and glass beads, can also be used in combination.

[0074] 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.

[0075] The glass fiber of the present invention can be used alone. Because the fiber diameter of the glass fiber has stable dimensional accuracy, it is also suitable for use as a spacer for maintaining the gap between two glass substrates in liquid crystal display devices used as display devices for liquid crystal televisions and personal computers.

[0076] Furthermore, the glass fiber of the present invention can be recycled. That is, the glass fiber can be extracted from an article containing the glass fiber of the present invention, remelted, and molded into a fiber shape or various shapes other than fiber, such as spheres or granules, and used for other purposes. For example, it can be used as a soil additive, a concrete additive or aggregate, an asphalt additive, etc.

[0077] The glass fiber composition has been described above, but the above-described glass composition can also be used for applications other than glass fiber. Specifically, the glass composition of the present invention can be used, for example, for liquid crystal displays, or for applications other than liquid crystal displays, specifically for building materials and electronic components. The glass composition of the present invention contains, in mass %, 40-60% SiO, 10-30% AlO, 0-10% BO, 5-20% MgO, 5-20% CaO, 0-10% SrO, and 0-10% BaO. The reasons for limiting the glass composition in this way, preferred ranges, and other components that can be added are the same as those described for the glass fiber composition. [Example]

[0078] 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.

[0079] Tables 1 to 5 show examples of the present invention (samples Nos. 1 to 23).

[0080] [Table 1]

[0081] [Table 2]

[0082] [Table 3]

[0083] [Table 4]

[0084] [Table 5] Each sample was prepared as follows.

[0085] First, a raw material 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 raw material batch was placed in a platinum-rhodium crucible and heated and melted in an air atmosphere at 1500°C for 24 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.

[0086] Thereafter, the molten glass in a homogeneous state was poured into a carbon mold, cast into a predetermined shape, and slowly cooled to obtain a glass sample.

[0087] The properties of the obtained glass samples were measured according to the following procedures.

[0088] The forming temperature Tx was measured as follows. First, a lump glass sample was crushed to an appropriate size to prepare glass powder. The obtained glass powder was placed in an alumina crucible, taking care to avoid trapping air bubbles as much as possible. Next, the alumina crucible was heated to turn the glass sample into a molten liquid. The viscosity of the glass at multiple temperatures was measured using the platinum sphere pulling method, and the constants of the Vogel-Fulcher equation were calculated to create a viscosity curve. 3 The molding temperature Tx corresponding to dPa·s was calculated.

[0089] The liquidus temperature Ty was measured as follows. Glass powder that passed through a standard sieve (300 μm) and remained on a 50 mesh (300 μm) sieve was packed into a platinum container to an appropriate bulk density, placed in an indirect heating gradient furnace with a maximum temperature set to 1350°C, and heat-treated in the air for 24 hours. The platinum container containing the glass sample was then removed, and the glass sample was allowed to cool to room temperature. The location where crystals began to precipitate was confirmed using a polarizing microscope, and the crystal precipitation temperature was calculated from the temperature gradient in the indirect heating furnace.

[0090] The temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty was calculated by (molding temperature Tx) - (liquidus temperature Ty).

[0091] The liquidus viscosity log η was determined by measuring the viscosity of the glass at the liquidus temperature Ty by the platinum sphere pull-up method.

[0092] The thermal expansion coefficient was evaluated by measuring the average linear thermal expansion coefficient of a sample processed into a cylindrical shape of 20 mm x 3.8 mmφ in a temperature range of 30 to 380° C. A NETZSCH dilatometer was used for the measurement.

[0093] The Young's modulus, rigidity modulus, and Poisson's ratio were measured at room temperature using a free resonance type elastic modulus measuring device (JE-RT3 manufactured by Nippon Technoplus) for plate-shaped samples (40 mm × 20 mm × 20 mm) whose surfaces had been polished with a polishing solution containing dispersed No. 1200 alumina powder.

[0094] The density ρ was measured by the well-known Archimedes method.

[0095] The specific Young's modulus was calculated by (Young's modulus E) / (density ρ).

[0096] As is clear from the table, all of Samples Nos. 1 to 23, which are examples, had a molding temperature Tx of 1400° C. or less and a ΔTxy of 0° C. or more. In addition, the Young's modulus E was as high as 90 GPa or more.

[0097] Next, examples of producing glass fibers and glass fiber-containing composite materials will be described.

[0098] A glass fiber composition having the glass composition of Example Sample No. 1 was melted, and then a bushing device with a platinum nozzle was used to continuously mold a plurality of glass monofilaments having a diameter of 3 μm. No thread breakage occurred during molding, and glass fibers with a stable fiber diameter were obtained.

[0099] The bushing device used was designed to operate a system that could constantly monitor the temperature of the molten glass inside the bushing device, which corresponds to the forming temperature Tx, using thermocouple measurement, with the monitored temperature range being ±20°C around the target forming temperature. If the temperature of the molten glass drops, heating is carried out to correct this, allowing for stable production.

[0100] Next, an appropriate amount of a silane coupling agent or the like was applied to the surface of the multiple glass monofilaments formed using the bushing device by dipping, and the resulting monofilaments were air-dried to obtain glass monofilaments coated with a sizing agent. Multiple glass monofilaments were bundled together to form glass strands, which were then dipped in molten polypropylene resin, dried, and cut to the desired length. This resulted in LFTPs (also called pellet molded bodies) in which the glass strands were oriented in the same direction.

[0101] The LFTP thus obtained was used as a raw material to produce a molded body (glass fiber-containing composite material), for example, by injection molding. The glass fibers contained in the molded body thus produced have long fiber lengths, which makes it possible to increase the mechanical strength of the molded body. For example, a plate-shaped product obtained using the LFTP as a raw material has excellent properties such as excellent bending strength.

[0102] As described above, the glass fiber and glass fiber-containing composite material using the glass fiber composition of the present invention exhibit excellent performance and can be applied to all fields of industry. [Industrial Applicability]

[0103] 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 aircraft-related applications, they can be used for aircraft substrates, interior materials, and vibration-proofing materials. In automotive-related applications, they can be used for vibration-damping reinforcement materials, bumpers, engine undercovers, fenders, roofing materials, bodies, spoilers, muffler filters, dash panels, radiators, timing belts, and the like. Furthermore, in marine-related applications, they can be used as substrates for motorboats, yachts, fishing boats, and the like. In construction, civil engineering, and building materials-related applications, they can be used for 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-related applications, they can be used for fishing rods, tennis rackets, golf clubs, skis, helmets, and the like. In addition, 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, outer covering materials for non-flammable heat insulating materials, reinforcing materials for resinoid grinding wheels, aluminum filtration filters, etc.; and in agricultural applications, it can be used for greenhouses, agricultural poles, silo tanks, etc.

Claims

1. In mass%, SiO ２ 40-60%, Al ２ O ３ 10-30%, B ２ O ３ 2. A composition for glass fibers comprising 0-10% of MgO, 5-20% of MgO, 5-20% of CaO, 0-10% of SrO, and 0-10% of BaO.

2. In mass%, B ２ O ３ 2. The composition for glass fibers according to claim 1, wherein the content is 0.01 to 10%.

3. In mass%, SiO ２ 2. The glass fiber composition according to claim 1, wherein the content is 40 to 55%.

4. In mass%, SiO ２ 40-55%, Al ２ O ３ 20-30%, B ２ O ３ 2. The composition for glass fibers according to claim 1, wherein the content is 0.01 to 10%.

5. In mass ratio, SiO ２ / Al ２ O ３ The composition for glass fibers according to claim 1, wherein the ratio of the viscosity of the glass fiber to the viscosity of the glass fiber is 1.35 to 4.

6. 2. The composition for glass fibers according to claim 1, wherein the mass ratio of MgO / CaO is 0.5 to 3.

7. In mass%, ZrO ２ 2. The composition for glass fibers according to claim 1, wherein the composition contains 0.001% or more of SiO.

8. 2. The glass fiber composition according to claim 1, wherein the content of the rare earth element oxide is 8% or less by mass.

9. In mass%, SiO ２ 50-55%, Al ２ O ３ 20-24%, B ２ O ３ 2. The glass fiber composition according to claim 1, comprising 0.01-2.5% of Mo, 8-20% of MgO, and 5-10% of CaO.

10. In mass%, Li ２ O+Na ２ O+K ２ 2. The glass fiber composition according to claim 1, wherein O is 1% or less.

11. 2. The glass fiber composition according to claim 1, characterized in that the Young's modulus is 90 GPa or more.

12. 2. The composition for glass fibers according to claim 1, characterized in that the molding temperature is 1400° C. or less.

13. 2. The composition for glass fibers according to claim 1, wherein a temperature difference ΔTxy between the molding temperature and the liquidus temperature is 0° C. or more.

14. Density is 2.75 g / cm ３ 2. The glass fiber composition according to claim 1, wherein:

15. A glass fiber comprising the glass fiber composition according to any one of claims 1 to 14.

16. A glass fiber-containing composite material, which is a composite material comprising the glass fiber according to claim 15 and a matrix material.

17. In mass%, SiO ２ 40-60%, Al ２ O ３ 10-30%, B ２ O ３ A glass composition comprising 0-10% of CaO, 5-20% of MgO, 5-20% of CaO, 0-10% of SrO, and 0-10% of BaO.

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