Glass fiber

Abstract

The present disclosure provides new glass fibers that are suitable for reinforcing an inorganic hardened body such as cement, mortar, concrete, calcium silicate plates, and gypsum. Glass fibers according to the present disclosure are to be used for an inorganic hardened body, and each contain a glass composition including components satisfying 50≤SiO2≤65, 0≤B2O3<2, 5≤Al2O3≤14, 10≤CaO≤30, 0≤(Li2O+Na2O+K2O)≤4, and 0≤ZrO2≤7, all expressed in mass%.

Description

Glass fiber

[0001] The present invention relates to glass fibers for inorganic hardened products, specifically glass fibers suitable for incorporation into cement, mortar, concrete, calcium silicate board, gypsum, and the like.

[0002] Glass fiber reinforced cement is a composite material of cement and glass fibers that aims to control the tensile strength and ductility of cement. Mortar (cement mortar) is a building material made by solidifying fine aggregates such as sand with a cement paste made by adding water to cement, while concrete (cement concrete) is made by solidifying coarse and fine aggregates such as gravel with a cement paste. Cement mixed with water produces calcium hydroxide (Ca(OH)2) and other alkaline compounds, making it alkaline. For this reason, alkali-resistant glass fibers are used for cement reinforcement. AR glass is known as a composition of alkali-resistant glass fiber. AR glass contains, by mass, 16.8% zirconium oxide (ZrO2) and 14.5% alkali metal oxides. Patent Document 1 discloses an improved composition of AR glass.

[0003] Japanese Unexamined Patent Publication No. 56-134534

[0004] Glass fibers are widely used as fibers for reinforcing not only cement-based hardened bodies such as cement and mortar, but also various inorganic hardened bodies including calcium silicate boards. Demand for inorganic hardened bodies reinforced with glass fibers is expanding, and their use is also tending to diversify. Accordingly, there is a growing need for new glass fibers suitable for reinforcing inorganic hardened bodies. Therefore, an object of the present invention is to provide a new glass fiber suitable for reinforcing inorganic hardened bodies.

[0005] The present invention provides a glass fiber for an inorganic hardened body, comprising a glass composition containing, expressed in mass%, the following components: 50≦SiO2≦65, 0≦B2O3<2, 5≦Al2O3≦14, 10≦CaO≦30, 0≦(Li2O+Na2O+K2O)≦4, 0≦ZrO2≦7.

[0006] According to the present invention, a new glass fiber suitable for reinforcing inorganic cured materials is provided.

[0007] The following describes embodiments of the present invention, but the following description is not intended to limit the present invention to any particular embodiment. In this specification, "substantially free" and "substantially free" mean a content of less than 0.1 mass%, less than 0.05 mass%, less than 0.01 mass%, even less than 0.005 mass%, particularly less than 0.003 mass%, and in some cases less than 0.001 mass%. "Substantially" allows for the inclusion of trace amounts of impurities derived from glass raw materials, manufacturing equipment, molding equipment, etc. "Major component" refers to the component with the highest content by mass. "T-Fe2O3" refers to total iron oxide converted to diiron trioxide (Fe2O3). "Alkali metal oxide" refers to lithium oxide (Li2O), sodium oxide (Na2O), and potassium oxide (KO). The upper and lower limits of the content described below can be combined arbitrarily.

[0008] According to this embodiment, the balance of the components constituting the glass composition has been considered, and as a result, a glass fiber suitable for reinforcing an inorganic hardened body is provided. Hereinafter, each component constituting the glass composition in this embodiment will be described.

[0009] <Components of Glass Composition> (SiO2) Silicon dioxide (SiO2) is a component that forms the glass skeleton and is the main component of the glass composition. SiO2 also adjusts the devitrification temperature and viscosity during glass formation and improves acid resistance. When the SiO2 content is 50% by mass or more and 65% by mass or less, the increase in the devitrification temperature of the glass that would make glass production difficult is suppressed, and the acid resistance and alkali resistance of the glass are enhanced. Furthermore, within this range, the melting point of the glass does not become excessively high, improving uniformity during melting of raw materials. The lower limit of the SiO2 content can be 51% by mass or more, 52% by mass or more, 53% by mass or more, 54% by mass or more, 55% by mass or more, 56% by mass or more, 57% by mass or more, 58% by mass or more, or more than 59% by mass, or even more than 60% by mass. The upper limit of the SiO2 content may be 64% by mass or less, or may be 63% by mass or less.

[0010] (B2O3, Al2O3) Diboron trioxide (B2O3) is a component that forms the framework of glass. B2O3 is also a component that adjusts the devitrification temperature and viscosity during glass formation. On the other hand, excessive B2O3 content reduces the acid resistance and alkali resistance of the glass. The lower limit of the B2O3 content may be 0.1 mass% or more. The upper limit of the B2O3 content may be less than 2 mass%, or may be 1.5 mass% or less, 1 mass% or less, or 0.5 mass% or less. The upper limit of the B2O3 content may be 0.1 mass% or less. The glass composition may be substantially free of B2O3.

[0011] Aluminum oxide (Al2O3) is a component that forms the skeleton of glass. Al2O3 also adjusts the devitrification temperature and viscosity during glass formation, improving the water resistance of glass. However, excessive Al2O3 content reduces the acid and alkali resistance of glass. An Al2O3 content of 5% by mass or more and 14% by mass or less suppresses the increase in the devitrification temperature of glass that would make glass production difficult, while enhancing the acid and alkali resistance of glass. Furthermore, the melting point of glass is not excessively elevated, improving uniformity during melting of raw materials. The lower limit of the Al2O3 content can be 6% by mass or more, 7% by mass or more, 8% by mass or more, 8.5% by mass or more, 9% by mass or more, 9.5% by mass or more, 10% by mass or more, 10.5% by mass or more, 11% by mass or more, or even 11.1% by mass or more. The upper limit of the Al2O3 content may be 13 mass% or less, 12.5 mass% or less, less than 12 mass%, or even 11.9 mass% or less.

[0012] When the sum of the contents of B2O3 and Al2O3 (B2O3 + Al2O3) is 5% by mass or more and less than 16% by mass, the devitrification temperature and viscosity of the glass melt can be kept within ranges suitable for glass production while preventing an excessive increase in the devitrification temperature. This range also makes it possible to improve the alkali resistance of the glass. The lower limit of (B2O3 + Al2O3) can be 6% by mass or more, 7% by mass or more, 8% by mass or more, 9% by mass or more, or even 10% by mass or more. The upper limit of (B2O3 + Al2O3) can be 15% by mass or less, 14% by mass or less, or even 13% by mass or less.

[0013] (CaO) Calcium oxide (CaO) is a component that adjusts the devitrification temperature and viscosity during glass formation. CaO also improves Young's modulus. When the CaO content is 10% by mass or more and 30% by mass or less, the Young's modulus is improved, and the devitrification temperature and viscosity during melting of the glass can be within a range suitable for glass production while suppressing an excessive increase in the devitrification temperature. The lower limit of the CaO content can be 12% by mass or more, 13% by mass or more, 14% by mass or more, 15% by mass or more, 16% by mass or more, 17% by mass or more, or even 18% by mass or more. The upper limit of the CaO content can be 28% by mass or less, 27% by mass or less, 26% by mass or less, or even 25% by mass or less, particularly 24% by mass or less.

[0014] (Li2O, Na2O, KO) Alkali metal oxides (Li2O, Na2O, KO) are components that adjust the devitrification temperature and viscosity during glass formation. When the total content of alkali metal oxides (Li2O + Na2O + KO) is 0% by mass or more and 4% by mass or less, the devitrification temperature and viscosity of the glass melt can be kept within ranges suitable for glass production while suppressing an excessive increase in the devitrification temperature. Furthermore, the increase in the melting point of the glass can be suppressed, enabling more uniform melting of the glass raw materials, while ensuring high heat resistance of the glass without an excessive decrease in the glass transition temperature. Furthermore, the acid resistance and alkali resistance of the glass are improved. On the other hand, excessive alkali metal oxide content reduces the Young's modulus of the glass and the elastic modulus of the glass fiber. The lower limit of (Li2O + Na2O + KO) may be greater than 0% by mass or may be 0.1% by mass or more. The upper limit of (Li2O + Na2O + KO) may be 3 mass% or less, 2 mass% or less, or less than 2 mass%. When alkali resistance of the glass composition is particularly important, the value of (Li2O + Na2O + KO) may be 0.1 mass% or less. The glass composition may be substantially free of alkali metal oxides. Li2O, Na2O, and KO are each optional components. In other words, the lower limit of the content of each of these components may be 0.

[0015] The lower limit of the lithium oxide (LiO) content may be 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or even 0.4% by mass or more. The upper limit of the LiO content may be 4% by mass or less, 3% by mass or less, 2% by mass or less, 1.5% by mass or less, or even 1% by mass or less.

[0016] The lower limit of the sodium oxide (NaO) content may be 0.1% by mass or more, or 0.2% by mass or more. The upper limit of the LiO content may be 4% by mass or less, or 3% by mass or less, 2% by mass or less, 1.5% by mass or less, or even 1% by mass or less.

[0017] The lower limit of the potassium oxide (K2O) content may be 0.1 mass% or more, or 0.2 mass% or more, and the upper limit of the K2O content may be 4 mass% or less, or 3 mass% or less, 2 mass% or less, 1.5 mass% or less, or even 1 mass% or less.

[0018] (SiO2-Al2O3) From the viewpoint of improving the acid resistance of glass, the lower limit of the value (SiO2-Al2O3) obtained by subtracting the Al2O3 content from the SiO2 content may be 40 mass% or more, 41 mass% or more, 42 mass% or more, 43 mass% or more, 44 mass% or more, 45 mass% or more, 46 mass% or more, 47 mass% or more, more than 48 mass%, 48.5 mass% or more, more than 49 mass%, or even 49.5% or more. Furthermore, the upper limit of (SiO2-Al2O3) may be 57 mass% or less, 56 mass% or less, 55 mass% or less, 54 mass% or less, 53 mass% or less, or even 52 mass% or less.

[0019] (SiO2-BO3-Al2O3) From the viewpoint of improving the acid resistance of glass, the lower limit of the value (SiO2-BO3-Al2O3) obtained by subtracting the BO3 content from the SiO2 content and then further subtracting the Al2O3 content may be 38 mass% or more, 40 mass% or more, 41 mass% or more, 42 mass% or more, 43 mass% or more, 44 mass% or more, 45 mass% or more, 46 mass% or more, 47 mass% or more, more than 48 mass%, 48.5 mass% or more, more than 49 mass%, or even 49.5% or more. Furthermore, the upper limit of (SiO2-BO3-Al2O3) may be 56 mass% or less, 55 mass% or less, 54 mass% or less, 53 mass% or less, 52 mass% or less, or even 51 mass% or less.

[0020] (SiO2 + Al2O3) With regard to the alkali resistance of glass, the value of the sum of the contents of SiO2 and Al2O3 (SiO2 + Al2O3) is important. From the viewpoint of improving the alkali resistance of glass, the lower limit of (SiO2 + Al2O3) is preferably 55 mass% or more, and may be 58 mass% or more, 60 mass% or more, 62 mass% or more, 64 mass% or more, 65 mass% or more, or 66 mass% or more. Furthermore, the upper limit of (SiO2 + Al2O3) is preferably 80 mass% or less, and may be 78 mass% or less, 76 mass% or less, 75 mass% or less, 74 mass% or less, or 73 mass% or less.

[0021] (SiO2 + BO3 + Al2O3) With regard to the alkali resistance of glass, the value of the total content of SiO2, BO3, and Al2O3 (SiO2 + BO3 + Al2O3) is important. From the viewpoint of improving the alkali resistance of glass, the lower limit of (SiO2 + BO3 + Al2O3) is preferably 55 mass% or more, and may be 58 mass% or more, 60 mass% or more, 62 mass% or more, 64 mass% or more, 65 mass% or more, or 66 mass% or more. Furthermore, the upper limit of (SiO2 + BO3 + Al2O3) is preferably 80 mass% or less, and may be 78 mass% or less, 76 mass% or less, 75 mass% or less, 74 mass% or less, or 73 mass% or less.

[0022] (MgO) The glass composition may further contain magnesium oxide (MgO). MgO is a component that adjusts the devitrification temperature and viscosity during glass formation. MgO is also a component that improves Young's modulus. On the other hand, excessive MgO content reduces the alkali resistance of the glass. The lower limit of the MgO content may be 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 1.5% by mass or more, or even 2% by mass or more. The upper limit of the MgO content may be 10% by mass or less, 8% by mass or less, 6% by mass or less, 5% by mass or less, 4.5% by mass or less, or 4% by mass or less.

[0023] (MgO + CaO) The value of the sum of the contents of MgO and CaO (MgO + CaO) is important for the meltability and formability of glass. From the viewpoint of obtaining meltability and formability suitable for glass production, the lower limit of (MgO + CaO) is preferably 15 mass% or more, and more preferably 16 mass% or more, 17 mass% or more, 18 mass% or more, 19 mass% or more, 20 mass% or more, 21 mass% or more, and 22 mass% or more in that order. Furthermore, the upper limit of (MgO + CaO) is preferably 40 mass% or less, and more preferably 35 mass% or less, 32 mass% or less, 30 mass% or less, 29 mass% or less, and 28 mass% or less in that order.

[0024] (SrO) The glass composition may further contain strontium oxide (SrO). SrO is a component that adjusts the devitrification temperature and viscosity during glass formation. On the other hand, excessive SrO content reduces the acid resistance of the glass. The lower limit of the SrO content may be 0.1 mass% or more, 0.5 mass% or more, 1 mass% or more, 2 mass% or more, 3 mass% or more, 4 mass% or more, 5 mass% or more, 6 mass% or more, 7 mass% or more, or even 8 mass% or more. The upper limit of the SrO content may be 25 mass% or less, 20 mass% or less, 15 mass% or less, 12 mass% or less, 10 mass% or less, 8 mass% or less, 6 mass% or less, or 5 mass% or less. The upper limit of the SrO content may be 2 mass% or less, 1.5 mass% or less, 1 mass% or less, 0.5 mass% or less, or even 0.1 mass% or less. The glass composition may be substantially free of SrO.

[0025] (MgO + CaO + SrO) With regard to the meltability and formability of glass, the value of the total content of MgO, CaO, and SrO (MgO + CaO + SrO) is important. From the viewpoint of obtaining meltability and formability suitable for glass production, the lower limit of (MgO + CaO + SrO) is preferably 15 mass% or more, and more preferably 18 mass% or more, 20 mass% or more, 21 mass% or more, 22 mass% or more, 23 mass% or more, 24 mass% or more, 25 mass% or more, 26 mass% or more, 27 mass% or more, and 28 mass% or more in that order. Furthermore, the upper limit of (MgO + CaO + SrO) is preferably 40 mass% or less, and more preferably 38 mass% or less, 36 mass% or less, 35 mass% or less, and 34 mass% or less in that order.

[0026] (BaO) The glass composition may further contain barium oxide (BaO). BaO is a component that adjusts the devitrification temperature and viscosity during glass formation. On the other hand, excessive BaO content reduces the acid resistance of the glass. The upper limit of the BaO content may be 10% by mass or less, 5% by mass or less, 2% by mass or less, 1.5% by mass or less, 1% by mass or less, 0.5% by mass or less, or even 0.1% by mass or less. The glass composition may be substantially free of BaO.

[0027] (MgO + CaO + SrO + BaO) With regard to the meltability and formability of glass, the value of the total content of MgO, CaO, SrO, and BaO (MgO + CaO + SrO + BaO) is important. From the viewpoint of obtaining meltability and formability suitable for glass production, the lower limit of (MgO + CaO + SrO + BaO) is preferably 15 mass% or more, and more preferably 18 mass% or more, 20 mass% or more, 21 mass% or more, 22 mass% or more, 23 mass% or more, 24 mass% or more, 25 mass% or more, 26 mass% or more, 27 mass% or more, and 28 mass% or more in that order. Furthermore, the upper limit of (MgO + CaO + SrO + BaO) is preferably 40 mass% or less, and more preferably 38 mass% or less, 36 mass% or less, 35 mass% or less, and 34 mass% or less in that order.

[0028] (ZnO) The glass composition may further contain zinc oxide (ZnO). ZnO is a component that adjusts the devitrification temperature and viscosity during glass formation. However, since the raw material for ZnO is relatively expensive, adding a large amount of ZnO will increase the raw material cost. The upper limit of the ZnO content may be 10% by mass or less, 5% by mass or less, 2% by mass or less, 1.5% by mass or less, 1% by mass or less, 0.5% by mass or less, or even 0.1% by mass or less. The glass composition may be substantially free of ZnO.

[0029] (TiO2) The glass composition may further contain titanium dioxide (TiO2). TiO2 is a component that improves the meltability and chemical durability of glass and improves its UV absorption characteristics. An appropriate amount of TiO2 also improves the acid resistance and water resistance of glass. However, since the raw material for TiO2 is relatively expensive, adding a large amount of TiO2 increases raw material costs. The lower limit of the TiO2 content may be 0.1% by mass or more. The upper limit of the TiO2 content may be 10% by mass or less, or may be 8% by mass or less, 7% by mass or less, 6% by mass or less, 5% by mass or less, less than 2% by mass, 1% by mass or less, 0.5% by mass or less, 0.3% by mass or less, or even 0.2% by mass or less. The glass composition may be substantially free of TiO2. The lower limit of the TiO2 content may be 0.5% by mass or more, 1% by mass or more, 1.5% by mass or more, 1.6% by mass or more, 2% by mass or more, 3% by mass or more, 4% by mass or more, 5% by mass or more, more than 5% by mass, or even 5.1% by mass or more.

[0030] (ZrO2) Zirconium oxide (ZrO2) is a component that adjusts the devitrification temperature and viscosity during glass formation. ZrO2 also improves the acid and alkali resistance of glass. However, since the raw materials for ZrO2 are relatively expensive, adding a large amount of ZrO2 increases raw material costs. A high ZrO2 content also increases the working temperature. The lower limit of the ZrO2 content may be 0.1 mass% or more. The upper limit of the ZrO2 content may be less than 6 mass%, or may be 5 mass% or less, 4 mass% or less, 3 mass% or less, 2 mass% or less, 1 mass% or less, 0.5 mass% or less, or even 0.1 mass% or less. The glass composition may be substantially free of ZrO2. The lower limit of the ZrO2 content may be 0.5 mass% or more, 1 mass% or more, 2 mass% or more, or even 3 mass% or more.

[0031] (Fe) The glass composition may further contain iron oxide. Iron (Fe) is usually Fe 2+ or Fe 3+ It exists in the state of Fe 3+ is a component that enhances the ultraviolet absorption properties of glass, and Fe 2+is a component that enhances the heat absorption properties of glass. Even if not intentionally included, Fe may be inevitably mixed in as a result of industrial raw materials. A low Fe content can prevent glass coloration. The upper limit of the Fe content, expressed in T-Fe2O3, can be 5% by mass or less, or 4% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.4% by mass or less, 0.3% by mass or less, 0.2% by mass or less, or even 0.1% by mass or less, less than 0.1% by mass, 0.08% by mass or less, 0.05% by mass or less, 0.04% by mass or less, or even 0.03% by mass or less. The lower limit of the Fe content, expressed in T-Fe2O3, can be 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, or even 0.2% by mass or more. Particularly in glass compositions with low alkali metal oxide contents, trace amounts of iron oxide can contribute to promoting fining of the glass.

[0032] (F2, Cl2) The glass composition may further contain fluorine (F2) and chlorine (Cl2). F2 is easily volatile, which may cause scattering during melting, and also makes it difficult to control the content in the glass. The upper limit of the F2 content may be 5% by mass or less, or may be 2% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.2% by mass or less, or even 0.1% by mass or less. The glass composition may be substantially free of F2.

[0033] Since Cl2 is easily volatile, it may scatter during melting, and there is also the problem that its content in glass is difficult to control. The upper limit of the Cl2 content may be 5 mass% or less, or may be 2 mass% or less, 1 mass% or less, 0.5 mass% or less, 0.2 mass% or less, or even less than 0.1 mass%. The glass composition may be substantially free of Cl2.

[0034] (Other Components) The glass composition may contain at least one other component selected from P2O5, Sc2O3, Y2O3, La2O3, CeO2, Pr2O3, Nd2O3, Pm2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, Lu2O3, WO3, Nb2O5, Y2O3, MoO3, Ta2O5, MnO2, and Cr2O3 in a content of 0% to 5% by mass. The allowable content of each of these components may be less than 2% by mass, less than 1% by mass, less than 0.5% by mass, or even less than 0.1% by mass. The total allowable content of these components may be 5% by mass or less, or may be less than 2%, less than 1%, less than 0.5%, or even less than 0.1% by mass. However, the above other components may not be substantially contained. Furthermore, oxides of light-bearing elements (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) may not be substantially contained.

[0035] The glass composition may also contain, as an additive, at least one selected from SO3, Br2, I2, SnO2, As2O3, and Sb2O3, each in a content of 0 mass% or more and 1 mass% or less. The allowable content of each of these components may be less than 0.5 mass%, less than 0.2 mass%, or even less than 0.1 mass%. The allowable total content of these components may be 1 mass% or less, less than 0.5 mass%, less than 0.2 mass%, or even less than 0.1 mass%. However, the above other components may not be substantially present.

[0036] The glass composition may contain HO, OH, H, CO, CO, He, Ne, Ar, and N, each at a content of 0% by mass or more and 0.1% by mass or less. The allowable content of each of these components may be less than 0.05% by mass, less than 0.03% by mass, or even less than 0.01% by mass. The allowable total content of these components may be 0.1% by mass or less, less than 0.05% by mass, less than 0.03% by mass, or even less than 0.01% by mass. However, the above other components may not be substantially present.

[0037] The glass composition may contain trace amounts of precious metal elements. For example, precious metal elements such as Pt, Rh, Au, and Os may be contained in a content of 0 mass % or more and 0.1 mass % or less, respectively. The allowable content of each of these components may be less than 0.1 mass %, less than 0.05 mass %, less than 0.03 mass %, or even less than 0.01 mass %. The allowable total content of these components may be 0.1 mass % or less, less than 0.05 mass %, less than 0.03 mass %, or even less than 0.01 mass %. However, the above other components may not be substantially present.

[0038] The glass composition may be a composition that is substantially free of CuO. The glass composition may be a composition that is substantially free of CoO. The glass composition may be a composition that is substantially free of PbO. The glass composition may be a composition that is substantially free of NiO.

[0039] The glass composition of this embodiment contains the following components expressed in mass %, and may further have the preferred compositions similarly expressed in mass % in the following paragraphs: 50≦SiO2≦65, 0≦B2O3<2, 5≦Al2O3≦14, 10≦CaO≦30, 0≦(Li2O+Na2O+K2O)≦4, 0≦ZrO2≦7

[0040] A composition containing the following components: 50≦SiO2≦65, 0≦B2O3<2, 5≦Al2O3≦14, 1≦MgO≦10, 15≦CaO≦30, 0≦ZrO2≦7, 0≦T-Fe2O3≦5, and substantially no alkali metal oxides, where the alkali metal oxide content is determined by the sum of the contents of Li2O, Na2O, and KO.

[0041] A composition containing the following components: 50≦SiO2≦65, 0≦B2O3<2, 5≦Al2O3≦14, 1≦MgO≦10, 15≦CaO≦30, 0≦(Li2O+Na2O+K2O)≦4, 0≦ZrO2≦7, 0≦T-Fe2O3≦5.

[0042] A composition containing the following components: 50≦SiO2≦65, 0≦B2O3<2, 5≦Al2O3≦14, 10≦CaO≦30, 1≦SrO≦20, 0≦(Li2O+Na2O+K2O)≦4, 0≦ZrO2≦7, 0≦T-Fe2O3≦5.

[0043] A composition containing the following components: 50≦SiO2≦65, 0≦B2O3<2, 5≦Al2O3≦14, 10≦CaO≦30, 0≦(Li2O+Na2O+K2O)≦4, 0.1≦TiO2≦10, 0≦ZrO2≦7, 0≦T-Fe2O3≦5.

[0044] A composition containing the components 50≦SiO2≦65, 0≦B2O3<2, 5≦Al2O3≦14, 10≦CaO≦30, 0≦(Li2O+Na2O+K2O)≦4, 0.1≦ZrO2≦7, 0≦T-Fe2O3≦5, and substantially not containing TiO2.

[0045] A composition containing the components 50≦SiO2≦65, 0≦B2O3<2, 5≦Al2O3≦14, 10≦CaO≦30, 0≦(Li2O+Na2O+K2O)≦4, 0.1≦TiO2≦10, 0≦T-Fe2O3≦5, and substantially not containing ZrO2.

[0046] In each of the above compositions, B2O3 is not substantially contained.

[0047] A composition containing the following components: 50≦SiO2≦65, 0.1≦B2O3<2, 5≦Al2O3≦14, 0.1≦MgO≦10, 15≦CaO≦30, 0≦(Li2O+Na2O+K2O)≦4, 0≦ZrO2≦7, 0≦T-Fe2O3≦5.

[0048] In each of the above compositions, the relationship 0≦ZnO≦2 is further satisfied.

[0049] In each of the above compositions, the relationship 48≦(SiO2−Al2O3)≦57 holds. Glass compositions that satisfy this relationship are suitable for improving acid resistance. (SiO2−Al2O3) is the value obtained by subtracting the Al2O3 content from the SiO2 content on a mass basis. The lower limit of (SiO2−Al2O3) may be 49, and the upper limit may be 55.

[0050] In each of the above compositions (excluding compositions that do not substantially contain TiO2), the relationship 0.1≦TiO2≦2 is further satisfied.

[0051] <Characteristics> The characteristics that the glass composition of this embodiment can have are described below. (Melting Characteristics) The temperature at which the viscosity of molten glass reaches 1000 dPa·sec (1000 poise) is called the working temperature of the glass, and is the temperature most suitable for forming the glass. When producing glass fibers, if the working temperature of the glass is 1100°C or higher, the variation in glass fiber diameter can be reduced. If the working temperature is 1290°C or lower, the fuel cost for melting the glass can be reduced, glass manufacturing equipment is less susceptible to thermal corrosion, and the equipment life can be extended. The lower limit of the working temperature can be 1100°C or higher, and can also be 1120°C or higher, 1140°C or higher, 1150°C or higher, 1160°C or higher, 1170°C or higher, 1180°C or higher, or even 1200°C or higher. The upper limit of the working temperature may be 1290°C or less, 1270°C or less, 1260°C or less, or even 1250°C or less.

[0052] The larger the temperature difference ΔT obtained by subtracting the devitrification temperature from the working temperature, the less likely devitrification occurs during glass molding, and homogeneous glass can be produced with a high yield. ΔT can be 0°C or higher, or 10°C or higher, 20°C or higher, 30°C or higher, 40°C or higher, or even 50°C or higher. On the other hand, if ΔT is 200°C or lower, adjustment of the glass composition becomes easier. ΔT can be 200°C or lower, or 180°C or lower, or even 160°C or lower. The devitrification temperature is the temperature at which crystals form in the molten glass base and begin to grow.

[0053] Among glass fibers, long glass fibers are produced, for example, by drawing out a molten glass base from a nozzle in a bushing provided at the bottom of a kiln, continuously winding it up with a winder, and spinning it into a fibrous form. Short glass fibers are produced, for example, by pouring a molten glass base from the bottom of a kiln into a spinner rotating at high speed, and then the fibrous glass that is ejected from holes provided on the side of the spinner by centrifugal force is further drawn thinly by pressure such as a gas jet. Taking these production steps into consideration, it is desirable for the glass composition to have excellent melting properties and good formability, to have appropriate temperature-viscosity characteristics, and to have a devitrification temperature lower than the working temperature.

[0054] (Young's Modulus) The higher the Young's modulus of the glass composition forming the glass fiber, the better the elasticity of the glass fiber, and the improved mechanical properties of inorganic hardened materials reinforced with glass fiber, including glass fiber reinforced cement. Here, the Young's modulus (GPa) can be determined by measuring the longitudinal wave velocity and shear wave velocity of elastic waves propagating through the glass using a conventional ultrasonic method, and then separately determining the density of the glass using the Archimedes method. The lower limit of this Young's modulus can be 85 GPa or more, 86 GPa or more, 87 GPa or more, 88 GPa or more, or even 89 GPa or more. The upper limit of the Young's modulus can be preferably 100 GPa or less, 99 GPa or less, 98 GPa or less, 97 GPa or less, 96 GPa or less, or even 95 GPa or less. As can be seen from the examples and comparative examples described below, the glass composition of this embodiment can have a higher Young's modulus than E-glass and AR-glass.

[0055] (Chemical Durability) Acid resistance and alkali resistance are suitable indicators of chemical durability in reinforcement applications of inorganic cured bodies. The mass loss rate ΔW1, described below, is used as an indicator of acid resistance, with a smaller ΔW1 indicating higher acid resistance. When glass fibers are used as reinforcing materials for cement, calcium silicate boards, etc., the ΔW1 of the glass fibers is preferably 5.0 mass% or less. The ΔW1 of the glass composition of this embodiment can be 5.0 mass% or less, 4.5 mass% or less, 4.0 mass% or less, 3.5 mass% or less, or even 3.0 mass% or less. The ΔW1 that can be achieved by this embodiment is, for example, 0.01 to 5.0 mass%.

[0056] The mass loss rate ΔW2, which will be described later, is used as an indicator of alkali resistance, with a smaller ΔW2 indicating higher alkali resistance. When glass fibers are used as a reinforcing material for cement, calcium silicate boards, or the like, the ΔW2 of the glass fibers is preferably 10.0 mass% or less. The ΔW2 of the glass composition of this embodiment can be 10.0 mass% or less, 9.0 mass% or less, 8.0 mass% or less, 7.0 mass% or less, or even 6.0 mass% or less. The ΔW2 that can be achieved by this embodiment is, for example, 0.1 to 10.0 mass%.

[0057] Glass fibers made from such glass compositions having excellent chemical durability can be suitably used as reinforcing materials for cement, mortar, concrete, calcium silicate boards, etc. In these applications, emphasis has been placed on alkali resistance, but considering use in highly acidic environments such as chemical plants and sewerage facilities, and exposure to acid rain, it is desirable to also attach importance to acid resistance.

[0058] <Glass Fiber> The glass fiber of this embodiment is composed of the glass composition described above. The glass fiber of this embodiment may be either long glass fiber or short glass fiber. Long glass fiber is produced by causing a viscosity-controlled glass melt to flow out of a nozzle and winding it up with a winder. This continuous fiber is cut to an appropriate length when used. Short glass fiber is produced by blowing off the glass melt with high-pressure air, centrifugal force, or the like. Short glass fiber is sometimes called glass wool because it has a cotton-like form.

[0059] The average fiber diameter of the glass fibers is, for example, 0.1 to 50 μm. The average fiber diameter of the glass fibers may be 0.1 μm or more, 0.2 μm or more, 0.3 μm or more, 0.4 μm or more, or even 0.5 μm or more, and may be 50 μm or less, 40 μm or less, 30 μm or less, or 25 μm or less. In the case of long glass fibers, the average fiber diameter may be 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, or even 5 μm or more. In the case of short glass fibers, the average fiber diameter may be 10 μm or less, 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or even 1 μm or less.

[0060] <Inorganic hardened product> The inorganic hardened product of this embodiment contains the glass fiber described above. That is, the inorganic hardened product of this embodiment is reinforced with glass fiber. Examples of inorganic hardened products include cement, mortar, concrete, calcium silicate board, and gypsum. However, the inorganic hardened product may be other than those described above as long as it can be produced by a manufacturing method involving hardening. Hardening is carried out, for example, by kneading a slurry prepared by adding water to the raw materials, or by using an autoclave. The inorganic hardened product may contain an organic substance as long as the remainder, excluding the glass fiber, is mainly composed of inorganic substances.

[0061] Hereinafter, the embodiments of the present invention will be described in more detail with reference to Examples and Comparative Examples. (Examples and Comparative Examples) Conventional glass raw materials such as silica sand were mixed to obtain the compositions shown in Tables 1 to 4, and batches of glass raw materials were prepared for each Example and Comparative Example. Each batch was heated to 1500 to 1600°C using an electric furnace to melt it, and maintained in this state for approximately 4 hours until the composition became uniform. Thereafter, a portion of the molten glass (glass melt) was poured onto an iron plate and slowly cooled to room temperature in the electric furnace to obtain a bulk glass composition (plate-shaped product, glass sample).

[0062] The evaluation method of the properties is explained below. (Working Temperature) The relationship between viscosity and temperature of the obtained glass composition was investigated by a conventional platinum sphere pulling method, and the working temperature was determined from the results. Here, the platinum sphere pulling method is a method of measuring viscosity by applying the relationship between the load (resistance) applied when immersing a platinum sphere in molten glass and pulling the platinum sphere up at a uniform speed, and the gravity and buoyancy acting on the platinum sphere, to Stokes' law, which shows the relationship between the viscosity and the falling speed of microparticles when they settle in a fluid.

[0063] (Devitrification Temperature) A glass composition pulverized to particle diameters of 1.0 to 2.8 mm was placed in a platinum boat and held for 2 hours in an electric furnace equipped with a temperature gradient (800 to 1400°C). The devitrification temperature was determined from the maximum temperature of the electric furnace corresponding to the position where crystals appeared. When the glass became cloudy and crystals could not be observed, the maximum temperature of the electric furnace corresponding to the position where cloudiness appeared was taken as the devitrification temperature. Here, the particle diameter is a value measured by a sieving method. Note that the temperature (temperature distribution within the electric furnace), which varies depending on the location within the electric furnace, was measured in advance, and the glass composition placed in a predetermined location within the electric furnace was heated at the temperature of the predetermined location measured in advance. The temperature difference ΔT is the temperature difference obtained by subtracting the devitrification temperature from the working temperature.

[0064] (Young's modulus) Young's modulus E is calculated by measuring the longitudinal wave velocity vl and the shear wave velocity vt of elastic waves propagating through glass using a conventional ultrasonic method, and then calculating E = 3ρ v from the density ρ of the glass measured separately using the Archimedes method. t 2 ・(v l2 -4 / 3・v t 2 ) / (v l 2 -v t 2 ) was calculated using the formula:

[0065] (Tensile Modulus) A glass fiber (filament) was produced using the obtained glass composition (bulk). That is, the glass composition (bulk) was remelted in an electric furnace and then formed into pellets while cooling. A glass fiber having a diameter of 15 μm was produced using these pellets. The tensile modulus of the obtained glass fiber was measured by a method in accordance with "Test method for tensile properties of carbon fiber single fiber R7606:2000" of the Japanese Industrial Standards (JIS).

[0066] (Chemical durability) Acid resistance: A 15 μm diameter glass fiber was cut into a length of 20 mm, and a weight equivalent to the specific gravity of the glass was taken. The glass fiber was immersed in 100 mL of a 10% by weight aqueous sulfuric acid solution at 80°C for 24 hours. The mass loss rate was determined, and this mass loss rate was designated ΔW1. Alkali resistance: A 15 μm diameter glass fiber was cut into a length of 20 mm, and a weight equivalent to the specific gravity of the glass was taken. The glass fiber was immersed in 100 mL of a 10% by weight aqueous sodium hydroxide solution at 80°C for 24 hours. The mass loss rate was designated ΔW2. The mass loss rate was calculated based on the following formula, where Wa is the mass before immersion and Wb is the mass after immersion. Mass loss rate (%) = {(Wa - Wb) / Wa} x 100

[0067] The results of these measurements are shown in Tables 1 to 4. Note that the glass compositions in the tables are all values ​​expressed in mass %.

[0068]

[0069]

[0070]

[0071]

[0072] From Examples 1 to 41, Young's modulus was 88 to 95 GPa, tensile modulus was 76 to 87 GPa, working temperature was 1210 to 1283 ° C, ΔT (working temperature - devitrification temperature) was 4 to 78 ° C, ΔW1 was 0.26 to 3.48 mass%, and ΔW2 was 1.66 to 5.35 mass%.

[0073] The glass composition of Comparative Example 1 has an E-glass composition. E-glass has poor acid resistance (ΔW1) and is also somewhat inferior in Young's modulus and tensile modulus. The glass composition of Comparative Example 2 has an AR-glass (alkali-resistant glass) composition. AR-glass requires a large amount of ZrO2, which results in high raw material costs and a high working temperature. However, the Young's modulus and tensile modulus did not exceed those of the Examples.

Claims

1. A glass fiber for an inorganic hardened body, Expressed in mass %, 50≦SiO 2 ≦65、 0≦B 2 O 3 20 5≦Al 2 O 3 ≦14、 10≦CaO≦30, 0≦(L) 2 O+1 2 O+K 2 O)≦4、 0≦ZrO 2 ≦7、 A glass fiber comprising a glass composition containing the components:

2. The glass composition has a content of 0≦T-Fe, expressed in mass %. 2 O 3 2. The glass fiber of claim 1, wherein the composition is: However, T-Fe 2 O 3 is Fe 2 O 3 is the total iron oxides converted to

3. The glass composition comprises, in mass %, 50≦SiO 2 ≦65、 0≦B 2 O 3 20 5≦Al 2 O 3 ≦14、 1≦MgO≦10, 15≦CaO≦30, 0≦ZrO 2 ≦7、 0≦T-Fe 2 O 3 ≦5、 The glass fiber according to claim 2, which contains the components of the formula (I) and is substantially free of alkali metal oxides.

4. The glass composition comprises, in mass %, 50≦SiO 2 ≦65、 0≦B 2 O 3 20 5≦Al 2 O 3 ≦14、 1≦MgO≦10, 15≦CaO≦30, 0≦(L) 2 O+1 2 O+K 2 O)≦4、 0≦ZrO 2 ≦7、 0≦T-Fe 2 O 3 ≦5、 The glass fiber according to claim 2, comprising the components:

5. The glass composition comprises, in mass %, 50≦SiO 2 ≦65、 0≦B 2 O 3 20 5≦Al 2 O 3 ≦14、 10≦CaO≦30, 1≦SrO≦20, 0≦(L) 2 O+1 2 O+K 2 O)≦4、 0≦ZrO 2 ≦7、 0≦T-Fe 2 O 3 ≦5、 The glass fiber according to claim 2, comprising the components:

6. The glass composition comprises, in mass %, 50≦SiO 2 ≦65、 0≦B 2 O 3 20 5≦Al 2 O 3 ≦14、 10≦CaO≦30, 0≦(L) 2 O+1 2 O+K 2 O)≦4、 0.1≦TiO 2 ≦10、 0≦ZrO 2 ≦7、 0≦T-Fe 2 O 3 ≦5、 The glass fiber according to claim 2, comprising the components:

7. The glass composition comprises, in mass %, 50≦SiO 2 ≦65、 0≦B 2 O 3 20 5≦Al 2 O 3 ≦14、 10≦CaO≦30, 0≦(L) 2 O+1 2 O+K 2 O)≦4、 0.1≦ZrO 2 ≦7、 0≦T-Fe 2 O 3 ≦5、 and TiO 2 The glass fiber according to claim 2, which is substantially free of

8. The glass composition comprises, in mass %, 50≦SiO 2 ≦65、 0≦B 2 O 3 20 5≦Al 2 O 3 ≦14、 10≦CaO≦30, 0≦(L) 2 O+1 2 O+K 2 O)≦4、 0.1≦TiO 2 ≦10、 0≦T-Fe 2 O 3 ≦5、 Contains the component ZrO 2 The glass fiber according to claim 2, which is substantially free of

9. The glass composition is B 2 O 3 The glass fiber according to claim 1 , which is substantially free of

10. The glass composition comprises, in mass %, 50≦SiO 2 ≦65、 0.1≦B 2 O 3 20 5≦Al 2 O 3 ≦14、 0.1≦MgO≦10, 15≦CaO≦30, 0≦(L) 2 O+1 2 O+K 2 O)≦4、 0≦ZrO 2 ≦7、 0≦T-Fe 2 O 3 ≦5、 The glass fiber according to claim 2, comprising the components:

11. 2. The glass fiber according to claim 1, wherein the working temperature is 1290°C or less, when the temperature at which the viscosity of the glass composition is 1000 dPa·sec is defined as the working temperature.

12. 2. The glass fiber according to claim 1, wherein, when the temperature at which the viscosity of the glass composition is 1000 dPa·sec is defined as a working temperature, a temperature difference ΔT obtained by subtracting the devitrification temperature from the working temperature is 0°C or more.

13. 2. The glass fiber according to claim 1, wherein the Young's modulus of the glass composition is 85 to 100 GPa.

14. An inorganic cured product comprising the glass fiber according to any one of claims 1 to 13.