Composition for glass fibers

Abstract

Provided is a composition for a glass fiber having high elastic modulus and good productivity.　The composition for a glass fiber is characterized by containing 0-1 mass% of Li2O+Na2O+K2O and having a SiO2 / Al2O3 mass ratio of 1-4 and a MgO / CaO mass ratio of 0.2-3.9.

Description

[Technical Field]

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

[0002] Glass fibers (also called glass filaments or glass filaments) are generally manufactured by continuously forming (spinning) molten glass into fibers using a forming device called a bushing device (also called a platinum heating vessel), which has a roughly rectangular appearance. The bushing device is placed at the bottom of a pot-shaped container that has a function of temporarily holding molten glass. The bushing device is made of a heat-resistant metal material such as platinum and has a number of nozzle parts (or orifice parts) at its bottom. This bushing device brings the molten glass to the optimal temperature at the tip of the bushing nozzle, i.e., when its high-temperature viscosity is 10 3 The temperature is controlled to reach a temperature equivalent to dPa·s. Then, the molten glass is continuously drawn out from the bushing nozzle and rapidly cooled to form (spin) glass fibers.

[0003] When forming glass fibers, the liquidus temperature Ty of the molten glass is equal to the glass forming temperature Tx (the high-temperature viscosity of the glass is 10 3 When the temperature exceeds dPa·s, crystals that cause devitrification tend to precipitate in the molten glass near the bushing nozzle. As a result, the bushing nozzle can become clogged, leading to thread breakage, also known as a break. For this reason, the liquidus temperature Ty of the molten glass must be lower than the molding temperature Tx (i.e., the temperature difference ΔTxy = Tx - Ty > 0), and a larger temperature difference ΔTxy is preferable. However, increasing the molding temperature Tx increases the temperature difference (ΔTxy) between the liquidus temperature Ty and the molten glass. In this case, the increased energy required for melting leads to higher manufacturing costs and shortens the lifespan of ancillary equipment such as bushing devices. Therefore, it is preferable to keep the molding temperature Tx low.

[0004] Thus, controlling the molding temperature Tx and temperature difference ΔTxy is extremely important in the manufacture of glass fibers. At the same time, there is a demand for higher functionality in glass fiber-containing composite materials, and the demand for glass fibers with superior elastic modulus is increasing. As glass for glass fibers with such properties, S glass, which consists of a glass composition of SiO2, Al2O3, and MgO, and R glass, which consists of a glass composition of SiO2, Al2O3, MgO, and CaO are known, but these have high molding temperatures Tx and high liquidus temperatures Ty, resulting in small temperature differences ΔTxy, which has caused problems with 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). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Special Publication No. 2009-514773 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0007] However, Patent Document 1 does not disclose a glass fiber composition with a low fiberization temperature (i.e., molding temperature Tx) and a large ΔT (temperature difference ΔTxy). Furthermore, the elastic modulus of the glass fiber obtained in Patent Document 1 is not necessarily sufficiently high.

[0008] The object of this invention is to provide a glass fiber composition that has a high modulus of elasticity and good productivity. [Means for solving the problem]

[0009] The glass fiber composition of the present invention is characterized by containing 0-1% by mass of Li2O+Na2O+K2O, with a mass ratio of SiO2 / Al2O3 of 1-4 and MgO / CaO of 0.2-3.9. In this way, a glass fiber composition with a high modulus of elasticity and good productivity can be obtained. Here, "Li2O+Na2O+K2O" is the total amount of Li2O, Na2O, and K2O, "SiO2 / Al2O3" is the value obtained by dividing the SiO2 content by the Al2O3 content, and "MgO / CaO" is the value obtained by dividing the MgO content by the CaO content.

[0010] The glass fiber composition of the present invention preferably contains TiO2 0.01% to less than 3% by mass.

[0011] The glass fiber composition of the present invention preferably contains, by mass%, SiO2 25-70%, Al2O3 15-25%, MgO 0.6-15%, CaO 3-15%, and B2O 30-3%.

[0012] The glass fiber composition of the present invention contains, by mass%, SiO2 50-70%, Al2O3 15-25%, MgO 1.2-15%, CaO 3-15%, TiO2 0.01-3%, B2O3 0-3%, and Li2O+Na2O+K2O 0-1%, characterized in that the mass ratio of SiO2 / Al2O3 is 2-3.2 and MgO / CaO is 0.4-2.5.

[0013] The glass fiber composition of the present invention preferably has a molding temperature Tx of 1400°C or lower. This allows for fiberization at a lower temperature, thereby extending the lifespan of fiberization equipment such as bushings and reducing production costs. The molding temperature Tx is determined when the high-temperature viscosity of the molten glass is 10 3 This temperature corresponds to dPa·s.

[0014] The glass fiber composition of the present invention preferably has a temperature difference ΔTxy between the forming temperature Tx and the liquidus temperature Ty of 30°C or more. By doing so, it becomes possible to improve productivity. The liquidus temperature Ty is a value obtained by putting glass powder that passes through a standard sieve of 30 mesh (mesh opening 500 μm) and remains on a 50 mesh (mesh opening 300 μm) into a platinum boat, holding it in a temperature gradient furnace for 24 hours, and measuring the temperature at which crystals (primary phase) precipitate. The temperature difference ΔTxy is the difference between the forming temperature Tx and the liquidus temperature Ty.

[0015] The glass fiber composition 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 with a small strain with respect to stress and high physical strength.

[0016] The glass fiber of the present invention is characterized by containing 95% by mass or more of glass composed of the above glass fiber composition in terms of solid content. By doing so, it becomes possible to obtain glass fibers having a high elastic modulus. The solid content conversion is calculated by measuring the mass in a dried state such that the moisture on the glass surface is less than 0.1%, further performing a heat treatment, heating and removing the organic matter applied to the glass fiber surface, and then measuring the mass.

[0017] The glass fiber-containing composite material of the present invention is characterized by containing the above glass fiber and an organic medium, concrete or mortar. By doing so, it becomes possible to be used in a wide range of applications.

Advantages of the Invention

[0018] According to the present invention, it is possible to provide a glass fiber composition having a high elastic modulus and good productivity.

Embodiments for Carrying Out the Invention

[0019] The glass fiber composition of the present invention contains 0 to 1% of Li2O + Na2O + K2O in mass percentage, and the mass ratio of SiO2 / Al2O3 is 1 to 4, and the mass ratio of MgO / CaO is 0.2 to 3.9. The reasons for limiting the glass composition as described above are shown below. In the following explanations regarding the contents of each component, unless otherwise specified, "% " means "mass percentage".

[0020] Li2O, Na2O, and K2O have the effect of reducing the viscosity of the glass and promoting defoaming. However, if the content is too high, it becomes difficult to maintain the strength over time when made into a glass fiber-containing composite material, and it is preferably reduced as much as possible. Therefore, the content of Li2O + Na2O + K2O is preferably 0 to 1%, 0 to 0.8%, particularly 0 to 0.5%. In addition, the contents of Li2O, Na2O, and K2O are preferably 0 to 1%, 0 to 0.9%, 0 to 0.8%, 0 to 0.7%, 0 to 0.6%, particularly 0 to 0.5% respectively.

[0021] SiO2 is a major component that forms the glass skeletal structure. It is also a component that improves the mechanical strength and acid resistance of glass. If the SiO2 content is too low, the mechanical strength decreases and the elastic modulus becomes low, making it difficult to obtain sufficient strength. Therefore, the lower limit of the SiO2 content 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, and especially 55% or more. On the other hand, if the SiO2 content 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, it may become difficult to adjust the glass fiber diameter. In addition, high viscosity increases the energy required to melt the glass, and the molding temperature Tx also increases, leading to more severe damage to precious metal bushings, increasing the frequency of replacement and raising production costs. Therefore, the upper limit of the SiO2 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, 63% or less, 62.5% or less, 62% or less, 61.5% or less, 61% or less, 60.5% or less, 60% or less, 59.5% or less, 59% or less, 58.5% or less, 58% or less, 57.5% or less, 57% or less, less than 57%, 56.5% or less, less than 56.5%, and especially preferably 56% or less.

[0022] Al2O3 is a component that enhances the chemical durability and mechanical strength of glass. It suppresses crystal formation and phase separation in molten glass, thereby improving the elastic modulus of the glass. If the Al2O3 content is too low, the mechanical strength decreases and the elastic modulus becomes low, making it difficult to obtain sufficient strength. Therefore, the lower limit of the Al2O3 content is preferably 15% or more, 15.5% or more, 16% or more, 16.5% or more, 17% or more, 17.1% or more, 17.2% or more, 17.3% or more, 17.4% or more, 17.5% or more, 17.6% or more, 17.7% or more, 17.8% or more, 17.9% or more, and especially preferably 18% or more. On the other hand, if the Al2O3 content is too high, devitrified mullite crystals (3Al2O3·2SiO2) with Al2O3 as the main component are more likely to form in the molten glass. Furthermore, the viscosity of the molten glass becomes too high, making it difficult to achieve a homogeneous molten state, and as a result, the dimensional accuracy of the glass fiber diameter tends to decrease. In addition, the energy required to melt the glass increases, and the molding temperature Tx becomes higher, leading to more severe damage to the precious metal bushings, increasing the frequency of replacement and raising production costs. Therefore, the upper limit of the Al2O3 content is preferably 25% or less, and especially less than 25%.

[0023] Furthermore, if the mass ratio of SiO2 / Al2O3 is too small, devitrified crystals are more likely to form, reducing productivity. Also, the molding temperature Tx increases, the energy required to melt the glass increases, damage to the precious metal bushings becomes more severe, the replacement frequency increases, and production costs rise. On the other hand, if the SiO2 / Al2O3 ratio is too large, the elastic modulus decreases, making it difficult to obtain sufficient strength. Also, 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. Therefore, the lower limit of SiO2 / Al2O3 is preferably 1 or more, 1.1 or more, 1.2 or more, 1.3 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, 2.3 or more, 2.4 or more, and especially preferably 2.5 or more. The upper limit of SiO2 / Al2O3 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, and especially preferably 3.2 or less.

[0024] MgO is a component that acts as a flux, making it easier to melt glass raw materials. It reduces viscosity during glass melting, promotes bubble removal, and lowers the molding temperature (Tx). It also improves the mechanical strength of glass and enhances its 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 melt state, which in turn tends to reduce the dimensional accuracy of the glass fiber diameter. Furthermore, the molding temperature (Tx) increases, increasing the energy required to melt the glass, leading to more severe damage to precious metal bushings, increasing the frequency of replacement, and raising production costs. In addition, the mechanical strength decreases, and the elastic modulus and specific modulus become lower, making it difficult to obtain sufficient strength. 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, and especially 7% or more. On the other hand, if the MgO content is too high, in glass compositions with a high Al2O3 content, devitrified cordierite (2MgO·2Al2O3·5SiO2) crystals are more likely to form in the molten glass, which can cause clogging of the bushing nozzle during glass fiber molding. Therefore, the upper limit of the MgO content is preferably 15% or less, 14.5% or less, 14% or less, 13.5% or less, 13% or less, 12.5% ​​or less, 12.4% or less, 12.3% or less, 12.2% or less, 12.1% or less, and especially preferably 12% or less.

[0025] CaO, like MgO, acts as a flux that facilitates the melting of glass raw materials. It reduces viscosity during glass melting, promotes bubble removal, and lowers the molding 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 melt state, which in turn tends to reduce the dimensional accuracy of the glass fiber diameter. Furthermore, the molding temperature Tx increases, increasing the energy required to melt the glass, leading to more severe damage to the precious metal bushings, increasing the frequency of replacement, and raising production costs. Therefore, the lower limit of the CaO content is preferably 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.1%, 7.2%, 7.3%, 7.4%, and especially preferably 7.5% or higher. On the other hand, if the CaO content is too high, devitrified wollastonite (CaO·SiO2) crystals are more likely to form in the molten glass, which can cause clogging of the bushing nozzle during glass fiber molding. Furthermore, the mechanical strength decreases, and the elastic modulus and specific modulus become lower, making it difficult to obtain sufficient strength. 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 especially preferably 12% or less.

[0026] Furthermore, the mass ratio of MgO / CaO is preferably 0.2 to 3.9, with more preferably 0.3 to 3.5, 0.35 to 3, 0.35 to 2.5, 0.36 to 2.5, 0.37 to 2.5, 0.38 to 2.5, 0.4 to 2.5, 0.4 to 2.2, 0.4 to 2, 0.4 to 1.8, 0.4 to 1.7, and particularly preferably 0.4 to 1.65. If the MgO / CaO ratio is too low, devitrified wollastonite (CaO·SiO2) crystals are more likely to form in the molten glass, which can cause nozzle clogging of the bushing during glass fiber molding. In addition, the molding temperature Tx becomes higher, increasing the energy required to melt the glass, leading to more severe damage to the precious metal bushing, increased replacement frequency, and higher production costs. On the other hand, if the MgO / CaO ratio is too high, in glass compositions with a high Al2O3 content, devitrified cordierite (2MgO·2Al2O3·5SiO2) crystals are more likely to form in the molten glass, which can cause nozzle clogging of the bushing during glass fiber molding. In addition, the molding temperature Tx increases, the energy required to melt the glass increases, leading to more severe damage to the precious metal bushings, increased replacement frequency, and higher production costs.

[0027] In addition to the components mentioned above, the glass fiber composition of the present invention may also contain the following components in its glass composition.

[0028] SrO and BaO are components that reduce high-temperature viscosity. The SrO content is preferably 0-2%, 0-1.9%, 0-1.8%, 0-1.7%, 0-1.6%, 0-1.5%, 0-1.4%, 0-1.3%, 0-1.2%, 0-1.1%, 0-1%, 0-0.9%, 0-0.8%, 0-0.7%, 0-0.6%, 0-0.5%, 0.001-0.5%, 0.002-0.5%, 0.003-0.5%, 0.004-0.5%, 0.005-0.5%, 0.006-0.5%, 0.007-0.5%, 0.008-0.5%, 0.009-0.5%, 0.01-0.5%, and particularly preferably 0.05-0.5%, B The aO content is preferably 0-2%, 0-1.9%, 0-1.8%, 0-1.7%, 0-1.6%, 0-1.5%, 0-1.4%, 0-1.3%, 0-1.2%, 0-1.1%, 0-1.0%, 0-0.9%, 0-0.8%, 0-0.7%, 0-0.6%, 0-0.5%, 0.001-0.5%, 0.002-0.5%, 0.003-0.5%, 0.004-0.5%, 0.005-0.5%, 0.006-0.5%, 0.007-0.5%, 0.008-0.5%, 0.009-0.5%, 0.01-0.5%, and particularly preferably 0.05-0.5%. If the SrO and / or BaO content is too high, the phase separation of the molten glass tends to increase.

[0029] The amount of MgO+CaO+SrO+BaO is preferably 8-40%, 10-38%, 12-35%, and especially 15-30%. If the amount 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, and as a result, the dimensional accuracy of the glass fiber diameter tends to decrease. In addition, the molding temperature Tx increases, the energy required to melt the glass increases, damage to the precious metal bushing becomes more severe, the replacement frequency increases, and production costs increase. Furthermore, the mechanical strength decreases and the elastic modulus becomes low, making it difficult to obtain sufficient strength. On the other hand, if the amount of MgO+CaO+SrO+BaO is too high, devitrified crystals such as cordierite (2MgO·2Al2O3·5SiO2) and wollastonite (CaO·SiO2) tend to form in the molten glass, which may cause clogging of the bushing nozzle during glass fiber molding. Here, "MgO + CaO + SrO + BaO" represents the total amount of MgO, CaO, SrO, and BaO.

[0030] TiO2 is a component that improves the elastic modulus of glass, and in the SiO2-Al2O3-MgO composition system, it lowers the dedialysis temperature of mullite (3Al2O3·2SiO2) or cordierite (2MgO·2Al2O3·5SiO2). Furthermore, it can lower the melting temperature, viscosity, and molding temperature (Tx) of the glass, thus maintaining good productivity while preserving the elastic modulus of the resulting glass. If the TiO2 content is too low, the above effects become difficult to obtain. Therefore, the lower limit of the TiO2 content is 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% It is preferable that the content be 0% or more, 0.6% or more, 0.65% or more, 0.7% or more, 0.75% or more, 0.8% or more, 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, 1.25% or more, 1.3% or more, 1.35% or more, 1.4% or more, 1.45% or more, 1.5% or more, and especially more than 1.5%. It is preferable that the SiO2 content be relatively low (e.g., less than 57%) and the TiO2 content be relatively high (e.g., 1.0% or more), as this makes it easier to achieve both a low liquidus temperature and a high Young's modulus. On the other hand, if the TiO2 content is too high, TiO2-based devitrified 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 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%, 1.7%, and especially less than 1.7% and 1% or less.

[0031] ZrO2, like TiO2, is a component that improves the elastic modulus of glass. If the ZrO2 content is too low, the above effect becomes difficult to obtain. Therefore, the lower limit of the ZrO2 content is preferably 0% or more, 0.001% or more, 0.002% or more, 0.003% or more, 0.004% or more, and especially 0.005% or more. On the other hand, if the ZrO2 content is too high, it may raise the dedialysis outlet temperature of mullite (3Al2O3·2SiO2) or cordierite (2MgO·2Al2O3·5SiO2) in glass melts with an 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, and especially 1.65% or less.

[0032] Fe2O3, like ZrO2 and TiO2, is a component that improves the elastic modulus of glass. However, if the Fe2O3 content is too high, Fe2O3-based devitrified crystals are likely to form in the molten glass, which can cause clogging of the bushing nozzle during glass fiber molding. For this reason, the Fe2O3 content is preferably 0-3%, 0-2.9%, 0-2.8%, 0-2.7%, 0-2.6%, 0-2.5%, 0-2.4%, 0-2.3%, 0-2.2%, 0-2.1%, 0-2%, and especially 0.01-2%.

[0033] B2O3, like SiO2, is a component that forms the backbone of the glass network structure. It also has the function of reducing the viscosity of glass, promoting bubble removal, lowering the melting temperature and molding temperature (Tx) of glass, and improving the solubility of glass. The B2O3 content is preferably less than 0-3%, 0-2.9%, 0-2.8%, 0-2.7%, 0-2.6%, 0-2.5%, 0-2.4%, 0-2.3%, 0-2.2%, 0-2.1%, 0-2%, 0-1.9%, 0-1.8%, 0-1.7%, 0-1.6%, 0-1.5%, 0-1.4%, 0-1.3%, 0-1.2%, 0-1.1%, less than 0-1%, 0-0.9%, 0-0.8%, 0-0.75%, and especially preferably 0-0.7%. If the B2O3 content is too high, it can reduce the elastic modulus and increase the evaporation of boron components during melting, which can not only corrode the equipment but also contaminate the surrounding environment.

[0034] P2O5 is a component that suppresses devitrification crystallization and lowers the liquidus temperature Ty. The P2O5 content is preferably 0-2.0%, 0-1.5%, 0-1%, 0-0.7%, and especially 0-0.4%. If the P2O5 content is too high, the mechanical strength decreases and the elastic modulus becomes low, making it difficult to obtain sufficient strength.

[0035] Y2O3 is a component that improves the elastic modulus of glass, but if the Y2O3 content is too high, the density increases. Therefore, it is preferable that the Y2O3 content be 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 especially less than 0.1%.

[0036] Furthermore, for the purpose of improving clarity, one or more of the following may be included: SnO2, As2O3, Sb2O3, F2, CeO2, SO3, and Cl2. The content of each is preferably 0-2%, 0-1%, and particularly 0.01-0.8%.

[0037] To improve melting properties, elastic modulus, alkali resistance, acid resistance, water resistance, molding temperature, and liquidus temperature, other components such as ZnO, Cr2O3, MnO, La2O3, WO3, and Nb2O5 may be included in appropriate amounts as needed, up to 2% each.

[0038] Furthermore, the glass may contain up to 0.5% each of H2, O2, CO2, CO, H2O, He, Ne, Ar, N2, etc. It may also contain up to 500 ppm of noble metal elements such as Pt, Rh, and Au.

[0039] The properties of the glass fiber composition, glass fibers, and glass fiber-containing composite materials of the present invention will be described below.

[0040] The glass fiber composition of the present invention preferably has a molding temperature Tx of 1400°C or less, 1380°C or less, and particularly 1365°C or less. If the molding temperature Tx is too high, the energy required to melt the glass increases, leading to more severe damage to the precious metal bushings, 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 higher.

[0041] The glass fiber composition of the present invention preferably has a liquidus temperature Ty of 1300°C or less, 1280°C or less, and particularly 1265°C or less. If the liquidus temperature Ty is too high, the temperature difference ΔTxy tends to become small, which tends to worsen productivity. The lower limit of the liquidus temperature Ty is not particularly limited, but in reality it is 1000°C or higher.

[0042] 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 higher, 40°C or higher, 45°C or higher, 50°C or higher, 55°C or higher, 60°C or higher, 65°C or higher, 70°C or higher, 75°C or higher, 80°C or higher, 85°C or higher, and particularly 90°C or higher. If the temperature difference ΔTxy is too small, devitrified material that causes nozzle clogging of the bushing is more likely to occur during glass fiber molding, thus reducing productivity. The upper limit of the temperature difference ΔTxy is not particularly limited, but in reality it is 180°C or lower.

[0043] The glass fiber composition of the present invention preferably has an elastic modulus E of 80 GPa or more, 85 GPa or more, particularly 90 GPa or more. If the elastic modulus E is too low, it becomes difficult to achieve high functionality of the glass fiber-containing composite material. The upper limit value of the elastic modulus E is not particularly limited, but in reality it is 150 GPa or less.

[0044] The glass fiber composition of the present invention has a lower limit of density ρ of 2 g / cm 3 or more, 2.1 g / cm 3 or more, 2.2 g / cm 3 or more, 2.3 g / cm 3 or more, 2.4 g / cm 3 or more, 2.5 g / cm 3 or more, 2.55 g / cm 3 or more, particularly 2.6 g / cm 3 or more, and it is preferably so. If the density ρ is too low, the mechanical strength decreases, the elastic modulus E becomes low, and it becomes difficult to obtain sufficient strength. On the other hand, if the density ρ is too high, it becomes difficult to achieve high functionality of the glass fiber-containing composite material. Therefore, the upper limit of the density ρ is 3 g / cm 3 or less, 2.9 g / cm 3 or less, 2.8 g / cm 3 or less, particularly 2.7 g / cm 3 or less, and it is preferably so.

[0045] The glass fiber composition of the present invention preferably has a specific elastic modulus calculated by the elastic modulus 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. If the specific elastic modulus is too low, it becomes difficult to achieve high functionality of the glass fiber-containing composite material. The upper limit value of the specific elastic modulus is not particularly limited, but in reality it is 45 or less. <00​​The glass fibers of the present invention contain 95% or more of glass made from the glass fiber composition described above, on a solid content basis. If 95% or more of the glass fibers of the present invention are glass made from the glass fiber composition described above, and the remainder is an organic substance such as a coating agent, then scratches are less likely to occur on the surface of the glass fibers during various processing processes such as the glass fiber weaving process, and stable strength performance can be maintained. Furthermore, the glass fibers will be able to fully exhibit various physicochemical properties. The content of glass made from the glass fiber composition in the glass fibers of the present invention is 95 to 100% by mass on a solid content basis, 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 basis is calculated by measuring the mass in a dry state where the moisture content of the glass surface is less than 0.1% by mass, and then measuring the mass after heat treatment at a high temperature to remove the organic substance applied to the surface of the glass fibers by heating.

[0047] Furthermore, if the glass fiber composition has a solid content of less than 95% by mass, the protective performance of the organic material applied to the surface of the glass fiber will not be significantly improved, and the amount of organic material required for application will increase, leading to higher manufacturing costs and making it uneconomical. Also, if the glass fiber composition exceeds 99.99% by mass in terms of solid content, the protective performance of the glass fiber surface may not be sufficient.

[0048] Furthermore, the glass fibers of the present invention may have a cross-sectional shape perpendicular to the drawing direction during spinning, in addition to a circular shape, such as an ellipse, track shape, flat shape, rectangular shape, cocoon shape, and polygonal shape.

[0049] Furthermore, the glass fiber of the present invention is preferably in the form of chopped strands, yarn, or roving. This allows it to be used in a variety of applications.

[0050] Here, chopped strands are fibers obtained by cutting glass fiber bundles to a predetermined length, yarn is continuous glass fiber that has been twisted, and roving is made by aligning multiple strands of glass fiber bundles.

[0051] Regarding chopped strands, there are no limitations on fiber length or diameter, and those suitable for the application can be selected. Furthermore, any manufacturing method for chopped strands can be adopted. They can be directly processed into short fibers during the melting process, or they can be wound as long fibers and then cut using a cutting device according to the application. In this case, any cutting method can be used. For example, an outer-circumferential cutting device, an inner-circumferential cutting device, or a hammer mill can be used. There are also no particular limitations on the aggregate form of the chopped strands. That is, glass fibers cut to appropriate lengths can be laminated non-directionally on a plane and molded with a specific binder, or they can be arranged in a non-directional three-dimensional state. Alternatively, glass masterbatch (GMB) pellets (also called resin columnar bodies, LFTP, etc.) containing a high percentage of glass fibers may be used.

[0052] Regarding yarn, as long as it has the specified twist, there are no particular limitations on the size or direction of the twist, including untwisted yarn.

[0053] Furthermore, regarding roving, any appearance is acceptable as long as it is made by aligning and bundling multiple strands of glass fiber and winding them into a cylindrical shape. There are no limitations on the diameter of the wound fibers or the number of strands aligned.

[0054] Furthermore, the glass fibers of the present invention can also be used in forms other than those described above, such as continuous strand mats, bonded mats, cloths, tapes, woven fabrics, or milled fibers. They can also be used as resin-impregnated prepregs. In addition, the glass fibers can be used in various applications and molding methods, including spray-up, hand lay-up, filament winding, injection molding, centrifugal molding, roller molding, or BMC and SMC methods using match dies.

[0055] Furthermore, the glass fibers of the present invention can be given desired properties by applying various surface treatment agents. For example, sizing agents, binding agents, coupling agents, lubricants, antistatic agents, emulsifiers, emulsification stabilizers, pH adjusters, defoaming agents, colorants, antioxidants, antifungal agents, or stabilizers can be applied to the surface of the glass fibers in appropriate amounts, either individually or in any combination of multiple types, to coat them. Such surface treatment agents or coating agents may be starch-based or plastic-based.

[0056] For example, for FRP (fiber-reinforced plastic) bonding agents, acrylic, epoxy, urethane, polyester, vinyl acetate, vinyl acetate-ethylene copolymer, etc., can be used as appropriate.

[0057] The glass fiber-containing composite material of the present invention is characterized by containing the glass fibers described above, an organic medium, concrete, or mortar.

[0058] Here, the organic media mentioned above are typified by organic resins such as thermoplastic resins and thermosetting resins. Also, concrete is a mixture of cement, sand, gravel, and water, while mortar is a mixture of cement, sand, and water.

[0059] Regarding the type of organic medium, it is possible to use a single or multiple types of resin as appropriate depending on the application, and other structural reinforcing materials, such as carbon fibers, ceramic fibers, and bead materials, can also be used in combination.

[0060] Examples of the thermoplastic resins mentioned above 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.

[0061] Examples of the thermosetting resins mentioned above include epoxy resins, thermosetting modified polyphenylene ether resins, thermosetting polyimide resins, urea resins, allyl resins, silicon resins, benzoxazine resins, phenolic resins, unsaturated polyester resins, bismaleimidotriazine resins, alkyd resins, furan resins, melamine resins, polyurethane resins, and aniline resins.

[0062] Furthermore, there are no particular restrictions on the mixing ratios of the various components that make up concrete and mortar, or on the type of cement used. Fly ash and other materials can also be added.

[0063] The glass fibers of the present invention can be used on their own. For example, they are suitable for use as liquid crystal spacers in liquid crystal display devices used in liquid crystal televisions and personal computers, as the fiber diameter of the glass fibers has stable dimensional accuracy and is used to maintain the gap between two glass substrates.

[0064] Furthermore, the glass fiber composition and glass fibers of the present invention are recyclable. That is, articles containing the glass fiber composition and glass fibers of the present invention can be remelted and molded into fibrous shapes, or various shapes other than fibers such as spheres or granules, for use in other applications. For example, they can be used as soil additives, concrete additives, aggregates, or asphalt additives.

[0065] Next, the method for producing glass fibers according to the present invention will be described.

[0066] First, a batch of glass raw materials, prepared to have the above composition (and properties), is placed in a glass melting furnace, where it is vitrified, melted, and homogenized. The composition is as previously described, and will not be explained here.

[0067] Next, the molten glass is spun into glass fibers. More specifically, the molten glass is supplied to a bushing. The molten glass supplied to the bushing is continuously drawn out in a filamentous form from numerous bushing nozzles located on its bottom surface. Various treatment agents are applied to the monofilaments drawn out in this way, and glass fibers are obtained by bundling them together in predetermined quantities.

[0068] The glass fibers of the present invention, formed in this manner, can be processed into chopped strands, yarn, roving, etc., and used for various applications. [Examples]

[0069] The present invention will be described in detail below based on the following examples. Note that the following examples are merely illustrative. The present invention is not limited in any way to the following examples.

[0070] Tables 1-7 show examples of the present invention (samples No. 1-12, 14-102) and comparative examples (sample No. 13).

[0071] [Table 1]

[0072] [Table 2]

[0073] [Table 3]

[0074] [Table 4]

[0075] [Table 5]

[0076] [Table 6]

[0077] [Table 7]

[0078] Each sample was prepared as follows:

[0079] First, glass batches were prepared by weighing and mixing various glass raw materials using arbitrary natural and / or chemical raw materials to achieve the glass composition shown in the table. Next, these glass batches were placed in a platinum-rhodium crucible and heated and melted at 1550°C for 5 hours in an air atmosphere. In order to obtain homogeneous molten glass, the molten glass was stirred using a heat-resistant stirring rod during the heating and melting process.

[0080] Subsequently, the homogeneous molten glass was poured into a carbon mold and cast into the predetermined shape, and then slowly cooled to obtain the final glass molded body for measurement.

[0081] The physical properties of the obtained glass were measured using the following procedure.

[0082] The viscosity of the molten glass is 10 3 The molding temperature Tx, corresponding to dPa·s, was calculated by interpolating the viscosity curve obtained from multiple measurements of each viscosity, which were measured based on the platinum ball pulling method, after the molded glass was placed in an alumina crucible, reheated to a molten state, and then measured.

[0083] Furthermore, the liquidus temperature Ty was determined by filling a platinum container with glass powder that had passed through a standard 30-mesh (300 μm) sieve and remained in a 50-mesh (300 μm) sieve to an appropriate bulk density. The container was then placed in an indirect heating temperature gradient furnace set to a maximum temperature of 1320°C and left to stand for 16 hours in an atmospheric environment. After that, the platinum container containing the glass sample was removed, and the glass sample was taken out of the container. After the glass sample cooled to room temperature, the location where crystal precipitation began was confirmed using a polarizing microscope, and the crystal precipitation temperature was calculated from the temperature gradient in the indirect heating furnace.

[0084] The temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty was calculated using the formula (molding temperature Tx) - (liquidus temperature Ty).

[0085] The elastic modulus E was measured at room temperature using a free-resonance type elastic modulus measuring device (manufactured by Japan Techno Plus Co., Ltd.) on both surfaces of a plate-shaped sample measuring 40 mm x 20 mm x 2 mm, which was polished with an abrasive solution dispersed with 1200-grade alumina powder.

[0086] The density ρ was measured by the well-known Archimedes method.

[0087] The specific modulus of elasticity was calculated using the formula (modulus of elasticity E) / (density ρ).

[0088] As is clear from Table 1, all of the example samples No. 1-12 and 14-102 had a molding temperature Tx of 1400°C or less. Furthermore, their elastic modulus E was high, at 80 GPa or higher.

[0089] On the other hand, comparative example No. 13 had a high molding temperature Tx of 1430°C. [Examples]

[0090] Next, examples of the glass fibers and glass fiber-containing composite materials of the present invention will be given.

[0091] For example, by melting a glass fiber composition having the glass composition of Sample No. 1 in Example 1 and then using a bushing device with a platinum nozzle, glass monofilaments with a diameter of 3 μm can be continuously formed. Since thread breakage is less likely to occur even with continuous forming, it is possible to obtain glass fibers with a stable fiber diameter.

[0092] Furthermore, this bushing device is designed with a system that continuously monitors the temperature of the molten glass inside the bushing device, corresponding to the molding temperature Tx, using thermocouple measurement. The monitoring temperature range is ±20°C from the target molding temperature. If the molding temperature falls too low, heating is performed to correct it, enabling stable production.

[0093] Next, an appropriate amount of silane coupling agent or the like is applied to the surface of the glass fibers formed using the bushing device described above by immersion, and then air-dried to obtain glass fibers coated with a sizing agent. Multiple glass fibers are bundled together, solidified using an organic solvent made of polypropylene resin, and then cut to the desired length to obtain LFTP (also called a pelletized body) in which the glass fibers are oriented in the same direction.

[0094] By using the LFTP obtained in this way, the length of the glass fibers can be increased, making it possible to obtain high-strength glass fiber-containing composite materials. For example, if the bending strength of a plate-shaped material is evaluated, it will have performance equal to or better than conventional products.

[0095] As described above, glass fibers and glass fiber-containing composite materials using the glass fiber composition of the present invention exhibit excellent performance and can be applied to all fields of industry. [Industrial applicability]

[0096] Glass fibers and glass fiber-containing composite materials produced using the glass fiber composition of the present invention are expected to be used in a variety of applications. For example, in aerospace applications, they can be used as aircraft base materials, interior materials, vibration damping materials, etc. In automotive applications, they can be used as vibration damping reinforcement materials, bumpers, engine undercovers, fenders, roofing materials, bodies, spoilers, muffler filters, dash panels, radiators, timing belts, etc. In marine applications, they can be used in motorboats, yachts, fishing boats, etc. In construction, civil engineering, and building materials applications, they can be used in decorative walls, luminous ceilings and lighting covers, facade wallpaper, insect screens, roller blinds, tent membrane materials, backlit signs, corrugated sheets, flat sheets, and folded sheets for lighting, concrete corrosion protection and reinforcement materials, exterior wall reinforcement materials, waterproof coating materials, smoke barriers, non-combustible transparent partitions, projection films, road reinforcement materials, bathtubs, bathroom units, etc. In leisure and sports applications, they can be used in fishing rods, tennis rackets, golf clubs, skis, helmets, etc. Furthermore, in electronic equipment applications, it can be used in printed circuit boards, insulating boards, terminal boards, IC boards, electronic equipment housing materials, electronic component packaging materials, optical equipment housing materials, optical component packaging materials, and insulating supports. In industrial facility applications, it can be used in wind turbine blades, glass filter bags, non-combustible insulation material sheathing, resinoid grinding wheel reinforcement, and aluminum filtration filters. In agricultural applications, it can be used in greenhouses, agricultural poles, and silo tanks. In addition, the glass fiber composite material described above can also be used as a reinforcing material for known fiber-reinforced composite materials.

Claims

1. In mass%, SiO ２ 25-58%, MgO 0.6-15%, TiO2 0.01-3%, B2O3 0-3%, Li ２ O + Na ２ O+K ２ It contains 0-0.5% O, and by mass ratio, SiO ２ / Al ２ O ３ A glass fiber composition characterized by having 1 to 4 and an MgO / CaO ratio of 1.14 to 3.

9.

2. In mass %, Al ２ O ３ 15 to 25%, and CaO 3 to 15%, and the glass fiber composition according to claim 1, characterized by containing the same.

3. In mass%, SiO ２ 50-58%, Al ２ O ３ 15-25%, MgO 1.2-15%, CaO 3-15%, TiO ２ 0.01% to less than 3%, B ２ O ３ 0-3% or less, Li ２ O + Na ２ O+K ２ It contains 0-0.5% O, and by mass ratio, SiO ２ / Al ２ O ３ A glass fiber composition characterized by having a ratio of 2 to 3.2 and an MgO / CaO ratio of 1.14 to 2.

5.

4. A glass fiber composition according to any one of claims 1 to 3, characterized in that the molding temperature Tx is 1400°C or less.

5. A glass fiber composition according to any one of claims 1 to 4, characterized in that the temperature difference ΔTxy between the molding temperature Tx and the liquidus temperature Ty is 30°C or more.

6. A glass fiber composition according to any one of claims 1 to 5, characterized in that its elastic modulus E is 80 GPa or more.

7. A glass fiber characterized by containing 95% by mass or more, on a solid content basis, of glass made from the glass fiber composition described in any one of claims 1 to 6.

8. A glass fiber-containing composite material characterized by containing the glass fiber described in claim 7 and an organic medium, concrete, or mortar.

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