Fiberglass composition for higher modulus of elasticity

Abstract

To provide: a glass composition with a moderately high elastic modulus and a low fiberizing temperature, while having a lower manufacturing cost than high-modulus glass compositions; a glass fiber; and a method of forming a continuous glass fiber.SOLUTION: A glass composition is provided which includes about 57.0 to 62.0 mass% of SiO2, about 20.0 to 25.0 mass% of Al2O3, about 8.0 to 12.5 mass% of MgO, about 7 to 9.0 mass% of CaO, about 0.4 to 1.0 mass% of Li2O, 0.0 to about 1.0 mass% of Na2O, about 0 to 0.5 mass% of K2O; and 0.2 to about 1.5 mass% of TiO2. The glass composition has a fiberizing temperature of about 1,300°C or less. Such applications include nonwoven fabrics for use in forming wind blades and aerospace structures.SELECTED DRAWING: None

Description

[Technical Field]

[0001] Cross-references to related applications This application claims priority and all interests to U.S. Provisional Patent Application No. 62 / 956,422, filed 2 January 2020, the full disclosure of which is incorporated herein by reference. [Background technology]

[0002] Glass fibers are generally produced from various raw materials combined in specific proportions to obtain a desired composition, commonly referred to as a "glass batch." This glass batch can be melted in a melting apparatus, and the molten glass is stretched into filaments via bushings or orifice plates (the resulting filaments are also referred to as continuous glass fibers). Next, a sizing composition containing a lubricant, a coupling agent, and a film-forming binder resin can be applied to the filaments. After sizing, the fibers may be gathered into one or more strands and wound into a package, or the fibers may be chopped and collected while wet. These collected chopped strands can then be dried and cured to form dry chopped fibers, or they can be packaged in their wet state as wet chopped fibers.

[0003] Glass batches and the fiberglass compositions produced therefrom are often described in terms of the oxides they contain, which are generally SiO2. 2、 These include Al2O3, CaO, MgO, B2O3, Na2O, K2O, Fe2O3, TiO2, Li2O, etc. By changing the amount of these oxides or removing some of the oxides from a glass batch, numerous types of glass can be produced. Such glasses that can be produced include R-glass, E-glass, S-glass, A-glass, C-glass, and ECR-glass. The glass composition controls the formation of the glass and the properties of the product. Other characteristics of the glass composition include the cost of raw materials and environmental impact. For example, E-glass is an aluminoborsilicate glass, generally alkali-free, and commonly used in electrical applications. One advantage of E-glass is that its liquidus temperature allows for an operating temperature of approximately 1900°F to 2400°F (1038°C to 1316°C) for producing glass fibers. According to the ASTM classification for E-glass fiber yarns used in printed circuit boards and aerospace applications, its composition is defined as 52-56 mass% SiO2, 16-25 mass% CaO, 12-16 mass% Al2O3, 5-10 mass% B2O3, 0-5 mass% MgO, 0-2 mass% Na2O and K2O, 0-0.8 mass% TiO2, 0.05-0.4 mass% Fe2O3, and 0-1.0 mass% fluorine.

[0004] Boron-free fibers are marketed under the trademark ADVANTEX® (Owens Coming, Toledo, Ohio, USA). Boron-free fibers, such as those disclosed in U.S. Patent No. 5,789,329, which is incorporated herein by reference in its entirety, offer a significant improvement in operating temperature compared to boron-containing E-glass. Boron-free glass fibers meet the ASTM definition for E-glass fibers for general use. R-glass is a family of glasses primarily composed of silicon, aluminum, magnesium, and calcium oxides, with a chemical composition that produces glass fibers with higher mechanical strength than E-glass fibers. R-glass has a composition containing approximately 58–60 mass% SiO2, approximately 23.5–25.5 mass% Al2O3, approximately 14–17 mass% CaO and MgO, and less than approximately 2 mass% of various other components. R-glass contains more alumina and silica than E-glass, requiring higher melting and processing temperatures during fiber formation. Typically, the melting and processing temperatures for R-glass are higher than those for E-glass. Such high processing temperatures necessitate the use of platinum-wire-lined melting equipment, which is more expensive. Furthermore, in R-glass, for the liquidus temperature to approach the forming temperature, the glass needs to be fiberized at a lower viscosity than E-glass, which is conventionally fiberized at approximately 1000 poise or close to it. Fiberizing R-glass at a conventional viscosity of 1000 poise is likely to result in glass devitrification, which causes process interruptions and reduced productivity.

[0005] High-performance glass fibers possess greater strength and stiffness compared to conventional E-glass fibers. Stiffness is particularly important for modeling and performance in some products. For example, in power wind stations, composites prepared from glass fibers with good stiffness properties, such as wind turbine blades, allow for the use of longer blades while maintaining the blade deflection within acceptable limits. Elastic modulus (interchangeable with "Young's modulus") is a measure of fiber stiffness, defining the relationship between a stress applied to a material and the resulting strain. Stiff materials have a high elastic modulus and change their shape only slightly under elastic load. Soft materials have a low elastic modulus and change their shape considerably.

[0006] While various types of high-performance glass compositions have been developed, attempts are often made to maximize the elastic modulus and tensile strength of these compositions. However, if the elastic modulus of glass fibers increases beyond a certain point (i.e., above 92 GPa), the molds for composite wind blades may become longer, requiring the creation of new molds. Achieving a moderate elastic modulus that is compatible with current composite molds while maintaining a low fiberization temperature appears to be beneficial and cost-effective. A fiberization temperature of less than approximately 1,300°C allows for the use of most of the current state-of-the-art materials and technologies in the production of glass fibers, thus enabling compatibility with already established manufacturing facilities. Furthermore, having a similar fiberization temperature to other glass compositions already produced allows for a rapid operation of switching furnaces from producing one type of glass to another without needing to change the molding technology. From the perspective of energy use, and also from the perspective of platinum volatilization, lower fiberization temperatures are preferable. Platinum volatilizes more rapidly at higher temperatures, reducing the lifespan of the molding technology.

[0007] Manufacturers of wind turbine blades make significant investments in creating the molds used to form the blades. Furthermore, because wind blades become very large, entire plants are constructed around the manufacturing section for blades of a specific size. The goal is generally to maintain the increasing modulus of elasticity of the glass fibers to enable the production of longer blades, but it is also desirable to make the best possible use of existing molds and facilities. To achieve this, the glass fibers must exhibit properties within a performance range. If the modulus of elasticity of the glass is too good, ethically, a new mold must be created to utilize the higher performance. These fibers allow for a higher tolerance for manufacturing defects in these same molds. Therefore, it is desirable to optimize performance without necessarily increasing the size of the wind blades. In this field, there is a need for high-performance glass compositions that have acceptable formation characteristics, such as achieving a moderate but not excessively high modulus of elasticity, such as between 90 and 92 GPa, while also possessing a sufficiently low fiber formation temperature. [Overview of the project]

[0008] Various exemplary embodiments of the concept of the present invention relate to a glass composition comprising, expressed as a mass percentage of the total mass of the composition, 57.0 to 62.0% by mass of SiO2; 20.0 to 25.0% by mass of Al2O3; 7.0 to 9.0% by mass of CaO; 8.0 to 12.5% ​​by mass of MgO; 0 to 1.0% by mass of Na2O; 0 to 0.5% by mass of K2O; 0.4 to 1.0% by mass of Li2O; and 0.2 to 1.5% by mass of TiO2. The mass percentage (R1)(MgO+Al2O3) / (SiO2+CaO) is at least 0.47, and the mass percentage ratio (R3)(MgO / SiO2) is at least 0.19. This glass composition has a fiberization temperature of 1,300°C or less.

[0009] In any of the various embodiments, the total amount of SiO2, Al2O3, MgO, and CaO can be at least 98% by mass and less than 99.5% by mass. In any of the various embodiments, the composition contains 57.1% to less than 59% by mass of SiO2. In any of the various embodiments, the composition contains 7.9% by mass to less than 9.0% by mass of CaO. In any of the various embodiments, the composition contains more than 20% by mass to 21% by mass of Al2O3. In any of the various embodiments, the composition contains 0.45% to 0.8% by mass of Li2O. In any of the various embodiments, the glass composition does not contain rare earth element oxides. In any of the various embodiments, the composition is essentially free of B2O3. In any of the various embodiments, the composition contains 0.1 to 0.8% by mass of Na2O. In any of the various embodiments, the composition contains a mass percentage ratio (R2)(MgO+Al2O3+Li2O) / (CaO+SiO2+Na2O+K2O) greater than 0.46.

[0010] Further exemplary embodiments of the concept of the present invention relate to a glass composition comprising 58.0 to 6.20 mass% of SiO2; 20.0 to 25.0 mass% of Al2O3; 7.9 to 12.0 mass% of CaO; 8.0 to 12.5 mass% of MgO; 0 to 1.0 mass% of Na2O; 0 to 0.5 mass% of K2O; 0.4 to 1.0 mass% of Li2O; and 0.2 to 1.5 mass% of TiO2. In various exemplary embodiments, the composition comprises a mass percentage ratio (R2) greater than 0.46 (MgO + Al2O3 + Li2O) / (CaO + SiO2 + Na2O + K2O), and a mass percentage ratio (R3) (MgO / SiO2) of at least 0.19. In some embodiments, the glass composition has a fiberization temperature of 1,300°C or less.

[0011] In any of the various embodiments, the total amount of SiO2, Al2O3, MgO, and CaO can be at least 98% by mass and less than 99.5% by mass. In any of the various embodiments, the composition contains 57.1% to less than 59% by mass of SiO2. In any of the various embodiments, the composition contains 7.9% by mass to less than 9.0% by mass of CaO. In any of the various embodiments, the composition contains more than 20% by mass to 21% by mass of Al2O3. In any of the various embodiments, the composition contains 0.45% to 0.8% by mass of Li2O. In any of the various embodiments, the glass composition does not contain rare earth element oxides. In any of the various embodiments, the composition is essentially free of B2O3. In any of the various embodiments, the composition contains 0.1 to 0.8% by mass of Na2O. In any of the various embodiments, the composition contains a mass percentage ratio of (R1)(MgO+Al2O3) / (SiO2+CaO) of at least 0.47.

[0012] A further exemplary embodiment of the concept of the present invention relates to glass fibers formed from a glass composition comprising 57.0 to 62.0 mass% of SiO2; 20.0 to 25.0 mass% of Al2O3; 7 to 9.0 mass% of CaO; 8.0 to 12.5 mass% of MgO; 0 to 1.0 mass% of Na2O; 0 to 0.5 mass% of K2O; 0.4 to 1.0 mass% of Li2O; and 0.2 to 1.5 mass% of TiO2. The glass composition has a mass percentage ratio of at least 0.47 (R1)(MgO+Al2O3) / (SiO2+CaO) and at least 0.19 (R3)(MgO / SiO2). The glass composition has a fiberization temperature of 1,300°C or less, and the glass fibers have an elastic modulus between 90 GPa and 92 GPa. In any of the various embodiments, the glass fiber is at least 2.6 g / cm³ 3 It has a density such that...

[0013] Further exemplary embodiments of the concept of the present invention relate to a method for forming continuous glass fibers, comprising the steps of preparing a molten composition according to any of the exemplary embodiments disclosed herein, and stretching the molten composition from an orifice to form continuous glass fibers. Further exemplary embodiments of the concept of the present invention relate to a reinforced composite product comprising a polymer matrix and a plurality of glass fibers formed from a glass composition comprising 57.0–62.0 mass% of SiO2; 20.0–25.0 mass% of Al2O3; 7–9.0 mass% of CaO; 8.0–12.5 mass% of MgO; 0–1.0 mass% of Na2O; 0–0.5 mass% of K2O; 0.4–1.0 mass% of Li2O; and 0.2–1.5 mass% of TiO2. In some exemplary embodiments, the glass composition has a mass percentage ratio of at least 0.47 (R1)(MgO+Al2O3) / (SiO2+CaO) and at least 0.19 (R3)(MgO / SiO2). This glass composition has a fiberization temperature of 1,300°C or less, and the glass fibers have an elastic modulus between 90 GPa and 92 GPa. The above and other objects, features, and advantages of the present invention will become fully apparent from the discussion in the detailed description that follows, and from the subsequent part of this specification. [Modes for carrying out the invention]

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which these exemplary embodiments belong. The technical terms used in the descriptions herein are solely for the purpose of illustrating the exemplary embodiments and are not intended to limit them. Therefore, the general concepts of the invention are not intended to be limited to the specific embodiments illustrated herein. Other methods and materials similar to or equivalent to those described herein may be used in carrying out or testing the invention, but preferred methods and materials are described herein. As used herein and in the appended claims, the singular forms "a," "an," and "the" are also intended to include the plural forms unless the context explicitly indicates otherwise.

[0015] "Substantially free" means that the composition contains less than 1.0% by mass of the listed constituents, including 0.8% by mass or less, 0.6% by mass or less, 0.4% by mass or less, 0.2% by mass or less, 0.1% by mass or less, and 0.05% by mass or less. In any of the exemplary embodiments, "substantially free" means containing less than 0.01% by mass of the listed constituents.

[0016] Unless otherwise indicated, all numbers expressing amounts of ingredients, chemical and molecular properties, reaction conditions, etc. used in this specification and the claims are to be understood as being modified in all instances by the term "about". Accordingly, unless otherwise indicated, the numerical parameters set forth in this specification and the appended claims are approximations that can vary depending upon the desired properties sought to be obtained by the exemplary embodiments of the present invention. At the very least, each numerical parameter should be construed in light of the number of significant figures and in accordance with ordinary rounding techniques. Unless otherwise indicated, any element, property, feature, or combination of elements, properties, and features can be used in any of the embodiments disclosed herein, regardless of whether the element, property, feature, or combination of elements, properties, and features is explicitly disclosed in the embodiment. It will be readily understood that any feature described with respect to any particular aspect described herein can be applicable to other aspects described herein, provided that the feature is compatible with that aspect. In particular: Features described herein with respect to the method can be applicable to glass fiber products, and vice versa. Features described herein with respect to the method can be applicable to glass compositions, and vice versa. And features described herein with respect to the glass fiber can be applicable to glass compositions, and vice versa.

[0017] Numerical ranges and parameters setting forth broad ranges of exemplary embodiments are approximations, and unless otherwise indicated, the numerical values set forth in the specific examples are reported as accurately as possible. However, any numerical value inherently contains a certain degree of error necessarily resulting from the standard deviation found in individual test measurements. Any numerical range recited throughout this specification and claims also subsumes any narrower numerical ranges that fall within such broader numerical ranges as if such narrower numerical ranges were all expressly recited herein. Further, any of the numerical values reported in the present examples can be used to define either the upper or lower endpoint of a broader composition range disclosed herein.

[0018] The present disclosure relates to a glass composition having a moderately high modulus of elasticity and a low fiberization temperature while having a cost less than that of conventional high modulus of elasticity glass compositions. The glass composition disclosed herein is suitable for melting in a glass furnace lined with a conventional commercially available refractory that is widely used in the production of glass reinforcing fibers. The glass composition may be in a molten form obtainable by melting the constituents of the glass composition in a melting apparatus. The glass composition exhibits a low fiberization temperature, which is defined as the temperature corresponding to a melt viscosity of about 1000 poises as determined by ASTM C965-96(2007). The reduction of the fiberization temperature enables a longer bushing life and a reduction in the amount of energy used to melt the constituents of the glass composition, so that the production cost of glass fibers can be reduced by the reduction of the fiberization temperature. Thus, the energy released is generally less than the energy required to melt a number of commercially available glass formulations. Such a lower energy requirement can also reduce the overall production cost associated with the glass composition.

[0019] For example, at lower fiberization temperatures, the bushing may be operated at cooler temperatures and therefore will not "deflate" as quickly as is usually observed. Deflection is a phenomenon that occurs when a bushing held at high temperatures for a long period of time loses its predetermined stability. Therefore, by lowering the fiberization temperature, the deflection rate of the bushing can be reduced, and the bushing life can be maximized. Furthermore, lower fiberization temperatures are better from an energy usage standpoint and also delay the volatilization of platinum.

[0020] In any of the exemplary embodiments, the glass composition may only have a fiberization temperature of less than 2,372°F (1,300°C), including fiberization temperatures of 2,363°F (1,295°C) or less, 2,354°F (1,290°C) or less, 2,345°F (1,285°C) or less, and 2,336°F (1,280°C) or less. In any of the exemplary embodiments, the glass composition may have a fiberization temperature between 2,330°F (1,276.76°C) and 2,366.6°F (1,297°C), or between 2,345°F (1,285°C) and 2,357.6°F (1,292°C). Another fibrous property of a glass composition is its liquidus temperature. The liquidus temperature is defined as the highest temperature at which equilibrium exists between the liquid glass and its primary crystalline phase. In some cases, the liquidus temperature can be measured by exposing the glass composition to a temperature gradient in a platinum alloy boat for 16 hours (ASTM C829-81(2005)). At all temperatures above the liquidus temperature, the glass is completely melted, i.e., crystal-free. At temperatures below the liquidus temperature, crystals may form. In any of the exemplary embodiments, the glass composition may have only liquidus temperatures below 2,350°F, including liquidus temperatures of 2,300°F (1,221.11°C) or less, 2,250°F (1,232.22°C) or less, 2,232°F (1,222.22°C) or less, 2,225°F (1,218.33°C) or less, and 2,220°F (1,215.56°C) or less. In any of the exemplary embodiments, the glass composition may have liquidus temperatures between 2,200°F (1,204.44°C) and 2,300°F (1,221.11°C), or between 2,210°F (1,210°C) and 2,235°F (1,223.89°C).

[0021] The third fiberization characteristic is "ΔT," also known as delta T, which is defined as the difference between the fiberization temperature and the liquidus temperature. If ΔT is too small, the molten glass may crystallize within the fiberization apparatus, potentially disrupting the manufacturing process. ΔT is desirable to be as large as possible for a given formation viscosity, as it provides greater plasticity during fiberization and helps avoid devitrification in both the glass distribution system and the fiberization apparatus. A larger ΔT further reduces the production cost of glass fibers by enabling a longer bushing life and a less susceptible formation process. In any of the exemplary embodiments, the glass composition may have a ΔT of at least 40°C, including at least 55°C, at least 60°C, at least 70°C, at least 75°C, at least 80°C, and at least 90°C. In various exemplary embodiments, the glass composition has a ΔT between 40°C and 90°C, including between 50°C and 85°C, and between 70°C and 80°C.

[0022] This glass composition may contain approximately 56.0 to 62.0% by mass of SiO2, approximately 17.0 to 24.0% by mass of Al2O3, approximately 9.0 to 13.0% by mass of MgO, approximately 7.0 to 11.0% by mass of CaO, approximately 0.0 to 1.0% by mass of Na2O, 0 to 2.0% by mass of TiO2, 0 to 1.5% by mass of Fe2O3, and approximately 0.2% to 1.0% by mass of Li2O. Advantageously, the ratio (R1)(MgO+Al2O3) / (SiO2+CaO) of the total mass percentage of alumina oxide and magnesium oxide to the total mass percentage of silicon dioxide and calcium oxide is at least 0.47, such as at least 0.48 and at least 0.49. An R1 ratio of at least 0.47 ensures that the resulting fiberglass exhibits a sufficiently high modulus of elasticity. In some exemplary embodiments, the ratio of the total mass percentage of MgO, Al2O3, and Li2O to the total mass percentage of CaO, SiO2, Na2O, and K2O, (R2)(MgO+Al2O3+Li2O) / (CaO+SiO2+Na2O+K2O), is greater than 0.46, including at least 0.47, at least 0.48, at least 0.49, and at least 0.50. In any of the exemplary embodiments, the ratio of the mass percentage of MgO to the mass percentage of SiO2 (R3) is greater than 0.175, such as greater than 0.18, greater than 0.19, or greater than 0.20.

[0023] The glass composition of the invention may contain any combination of R1, R2, and R3, but glass compositions satisfying each of the presented ratios have sufficiently high modulus of elasticity, specific modulus, and ΔT without the fiberization temperature exceeding 1,300°C. These ratios also result in a significant increase in intrinsic tensile strength. This glass composition contains SiO2 in an amount of at least 57% by mass, but 62% by mass or less. In some exemplary embodiments, this glass composition contains 57.1% by mass or more of SiO2, including 57.25% by mass or more, 57.3% by mass or more, 57.5% by mass or more, 57.7% by mass or more, and 58.0% by mass or more. In some exemplary embodiments, this glass composition contains 60.5% by mass or less of SiO2, including 60.3% by mass or less, 60.2% by mass or less, 60% by mass or less, 59.8% by mass or less, and 59.5% by mass or less. In some exemplary embodiments, this glass composition contains SiO2 between 57.15% by mass and less than 59% by mass.

[0024] To achieve both desired mechanical and fibrous properties, one important aspect of the glass composition is having an Al2O3 concentration of at least 19.0% by mass and no more than 25.0% by mass. Including less than 19.0% by mass of Al2O3 contributes to the formation of glass fibers with an unfavorably low modulus of elasticity. In some exemplary embodiments, the glass composition contains at least 19.5% by mass of Al2O3, including at least 19.7% by mass, at least 20.0% by mass, at least 20.05% by mass, at least 20.1% and at least 20.3% by mass. In some exemplary embodiments, the glass composition contains 22.0% by mass or less of Al2O3, including 21.8% by mass or less, 21.6% by mass or less, 21.2% by mass or less, 21.1% by mass or less, and 21.0% by mass or less. In any of the exemplary embodiments, the glass composition may contain Al2O3 between 20.0% by mass and less than 21.0% by mass. Adding a higher level of Al2O3 increases the tendency to crystallize.

[0025] The glass composition favorably contains MgO in an amount of at least 8.0% by mass and no more than 15.0% by mass. Inclusion of more than 15.0% by mass of MgO induces an increase in liquidus temperature, which also increases the crystallization tendency of the glass. Inclusion of less than 8.0% by mass results in the formation of glass fibers with an unfavorably low modulus of elasticity when replaced by CaO, and glass fibers with an unfavorably increased viscosity when replaced by SiO2. In any of the exemplary embodiments, the glass composition may contain at least 9.5% by mass of MgO, including at least 10.0% by mass, at least 10.5% by mass, at least 11.0% by mass, at least 11.10% by mass, and at least 11.50% by mass of MgO. In any of the exemplary embodiments, the glass composition may contain 12.5% ​​by mass or less of MgO, such as 12.0% by mass or less, 11.9% by mass or less, or 11.8% by mass or less. In any of the exemplary embodiments, the glass composition may contain 10.5% to less than 12.0% by mass of MgO.

[0026] The glass composition favorably contains CaO in an amount of at least 7.0% by mass and no more than 12.0% by mass. Including more than 12.0% by mass of CaO results in the formation of a glass with a low modulus of elasticity. Including less than 7.0% by mass results in an unfavorable increase in either the liquidus temperature or viscosity, depending on which oxide the CaO substitutes with. In any of the exemplary embodiments, the glass composition may contain at least 7.15% by mass of CaO, including at least 7.4% by mass, at least 7.7% by mass, at least 8.0% by mass, and at least 8.2% by mass. In any of the exemplary embodiments, the glass composition may contain 11.5% by mass or less of CaO, such as 10.0% by mass or less, 9.8% by mass or less, 9.5% by mass or less, and 9.0% by mass or less. In any of the exemplary embodiments, the glass composition may contain CaO concentrations between 7.9% by mass and less than 9.0% by mass. In any of the exemplary embodiments, the total amount of SiO2, Al2O3, MgO, and CaO may be at least 98.0% by mass, or at least 99% by mass and 99.5% by mass or less. In any of the exemplary embodiments, the total amount of SiO2, Al2O3, MgO, and CaO may be between 97.5% by mass and less than 99.5% by mass, such as between 98.0% by mass and less than 99.0% by mass, and between 98.05% by mass and 98.8% by mass.

[0027] This glass composition contains Li2O in an amount ranging from about 0.1% by mass to a maximum of about 2.0% by mass. The presence of Li2O lowers the fiberization temperature of the glass composition and improves the elastic modulus of the glass fibers formed from this glass composition. In any of the exemplary embodiments, this glass composition may contain about 0.2% by mass to about 1.0% by mass of Li2O, including about 0.4% by mass to about 0.8% by mass and about 0.45% by mass to about 0.7% by mass. In any of the exemplary embodiments, this glass composition may contain more than 0.45% by mass but less than 0.8% by mass of Li2O. The glass composition may contain up to about 2.0% by mass of TiO2. In any of the exemplary embodiments, the glass composition may contain about 0.05% by mass to about 1.5% by mass of TiO2, including about 0.4% to about 1.0% by mass and about 0.5% to about 0.7% by mass. The glass composition may contain up to about 2.0% by mass of Fe2O3. In any of the exemplary embodiments, the glass composition may contain about 0.05% by mass to about 1.0% by mass of Fe2O3, including about 0.2% by mass to about 0.8% by mass and about 0.3% by about 0.6% by mass.

[0028] In any of the exemplary embodiments, the glass composition may contain less than 2.0% by mass of alkali metal oxides Na2O and K2O, including amounts between 0 and 1.5% by mass. The glass composition may contain both Na2O and K2O in an amount greater than 0.01% by mass of each oxide, which is advantageous. In any of the exemplary embodiments, the glass composition may contain about 0 to about 1.0% by mass of Na2O, including about 0.01 to about 0.5% by mass, about 0.03 to about 0.3% by mass, and 0.04 to about 0.1% by mass. In any of the exemplary embodiments, the glass composition may contain about 0 to about 1% by mass of K2O, including about 0.01 to about 0.5% by mass, about 0.03 to about 0.3% by mass, and 0.04 to about 0.2% by mass.

[0029] As used herein, the terms “weight percent,” “% by weight,” “wt.%,” and “percent by weight” may be used interchangeably and mean weight percent (or percentage by weight) relative to the entire composition.

[0030] The glass compositions of the present invention may not contain, or substantially contain, B2O3, SrO, and fluorine. However, small amounts of any of these may be added to adjust the fiber formation properties and final glass properties, and maintaining a percentage of less than a few percent will not adversely affect the properties. As used herein, substantially free of B2O3, SrO, and fluorine means that the total amount of B2O3, SrO, and fluorine present is 1.0% by mass of the composition. The total amount of B2O3, SrO, and fluorine present may be less than about 0.5% by mass of the composition, including less than about 0.2% by mass, less than about 0.1% by mass, and less than about 0.05% by mass.

[0031] The glass composition may further contain impurities and / or trace substances without adversely affecting the glass or fibers. These impurities may be incorporated into the glass as raw material impurities or may be products formed by chemical reactions between the molten glass and the furnace components. Non-limiting examples of trace substances include zinc, strontium, barium, and combinations thereof. Trace substances may exist in their oxide forms and may further contain fluorine and / or chlorine. In any of the exemplary embodiments, the glass composition of the present invention may contain less than 1.0 mass% of each of BaO, SrO, ZnO, ZrO2, P2O5, and SO3, including less than 0.5 mass%, less than 0.2 mass%, and less than 0.1 mass%, respectively. In particular, this glass composition may contain less than approximately 5.0% by mass of BaO, SrO, ZnO, ZrO2, P2O5, and / or SO3 in total. In this case, even if BaO, SrO, ZnO, ZrO2, P2O5, and SO3 are present, they will each be present in amounts of less than 1.0% by mass.

[0032] In any of the exemplary embodiments, the glass composition may contain less than 2.0% by mass of the following modified components (collectively): CeO2, Li2O, Fe2O3, TiO2, WO3, and Bi2O3. In any of the exemplary embodiments, the glass composition may contain less than 1.5% by mass of the modified components. In any of the exemplary embodiments, the glass composition may contain less than 1.0 mass% of rare earth element oxides Y2O3, Ga2O3, Sm2O3, Nd2O3, La2O3, Ce2O3, and Sc2O3 ("R2O3") and Ta2O5, Nb2O5, or V2O5 ("R2O5"), including between 0 and 0.9 mass% or between 0 and 0.5 mass%. In some exemplary embodiments, the glass composition does not contain rare earth element oxides. As shown above, the glass composition of the present invention unexpectedly demonstrates a balance between a low fiberization temperature and moderate modulus (Young's modulus) and tensile strength, resulting in high-performance glass fibers for use in current composite mold specifications without requiring such downstream mold reconstruction.

[0033] The tensile strength of a fiber is also referred to herein simply as “strength.” In any of the exemplary embodiments, the tensile strength is measured against the original fiber (i.e., an unsized and untouched laboratory-produced fiber) using an Instron tensile testing apparatus in accordance with ASTM D2343-09. Exemplary glass fibers formed from the glass compositions of the present invention described above may have a fiber tensile strength of at least 4,500 MPa, including at least 4,600 MPa, at least 4,700 MPa, at least 4,800 MPa, at least 4,825 MPa, and at least 4,850 MPa. In any of the exemplary embodiments, glass fibers formed from the compositions described herein may have a fiber tensile strength of about 4,000 to about 5,000 MPa, including about 4,350 MPa to about 4,950 MPa and about 4,400 to about 4,900 MPa. Advantageously, by combining the compositional parameters disclosed herein, it is possible to produce glass fibers having a tensile strength of at least 4,800 MPa, including at least 4,850 MPa, while maintaining the desired fibrous properties and a moderate modulus of elasticity.

[0034] The elastic modulus of glass fibers can be determined by adopting the average measurement value for five single glass fibers measured in accordance with the acoustic measurement procedure outlined in the report “Glass Fiber and Measuring Facilities at the US Naval Ordnance Laboratory”, Report Number NOLTR 65-87, June 23, 1965.

[0035] Exemplary glass fibers formed from the glass composition of the present invention can have a moderately high modulus of elasticity (Young's modulus) between approximately 90 GPa and approximately 92 GPa. It is important to maintain a moderate modulus of elasticity not exceeding 92 GPa so that these glass fibers can be used in existing composite molds, thereby ensuring cost reductions compared to current glass compositions. A modulus of elasticity exceeding 92 GPa would necessitate a new composite mold, as it would require increasing the size of the composite. However, if the target modulus of elasticity is between 90 and 92 GPa, improvements in composite performance can be achieved within the range of current mold specifications. In any of the exemplary embodiments, the glass fibers formed according to this application can have a modulus of elasticity of at least 90.5 GPa, such as at least 90.6 GPa, at least 90.8 GPa, at least 91.0 GPa, or at least 91.2 GPa. In any of the exemplary embodiments, exemplary glass fibers formed from the glass composition of the present invention may have an elastic modulus between about 90.2 GPa and about 92 GPa, including between about 90.5 GPa and about 91.9 GPa and between about 90.7 GPa and about 91.8 GPa.

[0036] Next, the modulus of elasticity can be used to determine the specific modulus. It is desirable to have the highest possible specific modulus to achieve a lightweight composite material that imparts rigidity to the final article. The specific modulus is important in applications where the rigidity of the product is a critical parameter, such as in wind energy and aerospace applications. As used herein, the specific modulus is given by the following formula: Specific modulus of elasticity (MJ / kg) = Modulus of elasticity (GPa) / Density (kg / cubic meter) It is calculated by [this method]. The exemplary glass fibers formed from the glass composition of the present invention can have a specific modulus of elasticity ranging from about 32.0 MJ / kg to about 37.0 MJ / kg, including about 33 MJ / kg to about 36 MJ / kg and about 34.0 MJ / kg to about 35.0 MJ / kg. The density of unannealed bulk glass can be measured by any known and generally accepted method in the art, such as the Archimedes method (ASTM C693-93 (2008)). The density of glass fibers is approximately 2.0 to 3.0 g / cm³. 3 It has a density of about 2.40 to about 2.75 g / cm³. In particular, in any of the exemplary embodiments, the glass fibers have a density of about 2.40 to about 2.75 g / cm³. 3 , about 2.50~2.70g / cm 3 and approximately 2.60 to 2.68 g / cm³ 3 Including that, approximately 2.45 to 2.8 g / cm³ 3 It can have a density of .

[0037] In any of the exemplary embodiments, the glass fibers formed from the glass composition of the present invention may have improved corrosion resistance. According to some exemplary embodiments, a method for preparing glass fibers from the above-described glass composition is provided. The glass fibers can be formed by any means known and traditionally used in the art. The glass fibers are formed by obtaining crude components and mixing these components in appropriate amounts to yield a desired mass percentage of the final composition. The method may further include the step of preparing the glass composition of the present invention in molten form and stretching the molten composition through an orifice in a bushing to form glass fibers. Next, the mixed batch can be melted in a furnace or melting apparatus, and the resulting molten glass is passed along a front furnace and stretched through an orifice in a bushing located at the bottom of the front furnace to form individual glass filaments. In some exemplary embodiments, the furnace or melting apparatus is a conventional refractory melting apparatus. By utilizing a refractory tank formed from a refractory block, the manufacturing costs associated with producing the glass fibers produced by the composition of the present invention can be reduced. In some exemplary embodiments, the bushing is a platinum alloy-based bushing. Next, the individual filaments can be brought together to form strands of glass fibers. The fiber strands may be wound up and further processed in conventional methods suitable for the intended application.

[0038] The operating temperatures of the glass in the melting apparatus, pre-furnace, and bushing may be selected to appropriately adjust the viscosity of the glass and can be maintained using a suitable method such as a control device. The temperature at the front end of the melting apparatus may be automatically controlled to reduce or eliminate devitrification. The molten glass can then be stretched through holes or orifices in the bottom or front plate of the bushing to form glass fibers. According to some exemplary embodiments, the flow of molten glass through the bushing orifice is weakened to form filaments by winding strands formed from multiple individual filaments onto a forming tube mounted on a rotatable collet of a winding machine, or by engraving at a suitable speed. The glass fibers of the present invention can be obtained by any of the methods described herein or by any known method for forming glass fibers.

[0039] The fibers may be further processed in conventional methods suitable for the intended application. For example, in some exemplary embodiments, the glass fibers are sizing using sizing compositions known to those skilled in the art. The sizing composition is by no means limited and may be any sizing composition suitable for the application to the glass fibers. The sized fibers can be used in reinforced substrates such as various plastics, in which case the final use of the product requires high strength and rigidity, as well as low mass. Such applications include, but are not limited to, nonwovens for use in forming wind blades, reinforced concrete, foundation structures such as bridges, and aerospace structures. In this regard, any exemplary embodiment of the present invention may include a composite material incorporating the glass fibers of the present invention in combination with a curable matrix material. This is also referred to herein as a reinforced composite product. The matrix material may be any suitable thermoplastic or thermosetting resin known to those skilled in the art, including, but not limited to, thermoplastic resins such as polyester, polypropylene, polyamide, polyethylene terephthalate, and polybutylene, and thermosetting resins such as epoxy resins, unsaturated polyesters, phenolic resins, vinyl esters, and elastomers. These resins may be used alone or in combination. Reinforced composite products can be used in the manufacture of composites such as wind blades, reinforcing bars, pipes, filament windings, muffler fillers, and sound absorbers. According to further exemplary embodiments, the present invention provides a method for preparing the above-described composite product. The method may include the step of combining at least one polymer matrix material with a plurality of glass fibers. Both the polymer matrix material and the glass fibers may be as described above. [Examples]

[0040] Exemplary glass compositions according to the present invention were prepared by mixing batch components in proportional amounts to achieve the final glass composition, in the mass percentages of the oxides described in Tables 1 and 2 below. The raw materials were melted for 3 hours in a platinum crucible in an electrically heated furnace at a temperature of 1,650°C. The fibrous temperature was measured using the rotating cylinder method described in ASTM C965-96 (2007), entitled "Standard Practice for Measuring Viscosity of Glass Above the Softening Point," the contents of which are incorporated herein by reference. The liquidus temperature was measured by exposing the glass to a temperature gradient in a platinum alloy boat for 16 hours, as specified in ASTM C829-81 (2005), entitled "Standard Practices for Measurement of Liquidus Temperature of Glass," the contents of which are incorporated herein by reference. The density was measured by the Archimedes method, as detailed in ASTM C693-93 (2008), entitled "Standard Test Method for Density of Glass Buoyancy," the contents of which are incorporated herein by reference.

[0041] The specific modulus is calculated by multiplying the measured modulus of elasticity (Young's modulus) (in units of GPa) by density (g / cm³). 3 The calculation was performed by dividing by the unit of ( ). Tensile strength was measured against the original fibers using an Instron tensile testing apparatus according to ASTM D2343-09, titled "Standard Test Method for Tensile Properties of Glass Fiber Strands, Yarns, and Rovings Used in Reinforced Plastics," the details of which are incorporated herein by reference.

[0042] [Table 1]

[0043] [Table 2]

[0044] Tables 1 and 2 illustrate a particular balance of moderate modulus (between 90 and 92 GPa) and good tensile strength, achieved by glass fibers formed according to the concept of the present invention, while maintaining a fiberization temperature of less than 1,300°C. In particular, each of the glass compositions in Tables 1 and 2 demonstrates that the ratio (R1)(MgO+Al2O3) / (CaO+SiO2) is at least 0.47, the ratio (R2)(MgO+Al2O3+Li2O) / (CaO+SiO2+Na2O+K2O) is greater than 0.46, and the ratio (R3)(MgO / SiO2) is at least 0.19.

[0045] In contrast, Table 3 below details a comparative example from European Application No. 10860973.6. As illustrated, the exemplary comparative compositions fail to satisfy R1, R2, and R3 respectively, resulting in fiberization temperatures above 1,300°C and modulus values ​​above 92 GPa. The glass compositions of the present invention strike a balance between a moderate modulus (between 90 and less than 92 GPa) and good tensile strength, accompanied by a lower fiberization temperature.

[0046] [Table 3]

[0047] The present invention of this application is described above, both in general and with respect to specific embodiments. While the invention has been described in what are considered preferred embodiments, a wide range of alternatives known to those skilled in the art can be selected within the scope of the comprehensive disclosure. The invention is not particularly limited to the claims listed below. Another aspect of the present invention may be as follows: [1] 57.0 to 62.0 mass% of SiO 2 、 20.0-25.0% by mass of Al 2 O 3 、 CaO in an amount of 7.0-9.0 mass% 8.0-12.5% ​​by mass of MgO, 0-1.0% by mass of Na 2 O、 K in an amount of 0-0.5 mass% 2 O、 Li in an amount of 0.4 to 1.0 mass% 2 O, and 0.2 to 1.5 mass% of TiO 2 A glass composition comprising (R1)(MgO+Al) in a mass percentage ratio. 2 O 3 ) / (SiO 2 The ratio of (+CaO) is at least 0.47, and the mass percentage ratio (R3) (MgO / SiO) is at least 0.47. 2 A glass composition having a coefficient of at least 0.19 and a fiberization temperature of 1,300°C or lower. [2] SiO2 between 57.1% by mass and less than 59% by mass 2 The glass composition according to [1] above, comprising: [3] The glass composition according to [1] above, comprising 7.9% by mass to less than 9.0% by mass of CaO. [4] SiO 2 、Al 2 O 3 The glass composition according to [1], wherein the total amount of MgO and CaO is at least 98% by mass and less than 99.5% by mass. [5] The glass composition according to [1], which does not contain rare earth element oxides. [6] More than 20% by mass to 21% by mass of Al 2 O 3 The glass composition according to [1] above, comprising: [7] 0.45% to 0.8% by mass of Li 2 The glass composition according to [1] above, comprising O. 〔8〕B 2 O 3 A glass composition according to any one of the above items [1] to [6], which does not essentially contain the above. [9] 0.1 to 0.8 mass% Na 2 The glass composition according to [1] above, comprising O.

[10] Mass percentage ratio greater than 0.46 (R2) (MgO + Al 2 O 3 +Li 2 O) / (CaO+SiO 2 +Na 2 O+K 2 The glass composition described in [1] above, comprising O).

[11] SiO2 in an amount greater than 58.0% by mass and up to 62.0% by mass 2 、 20.0-25.0% by mass of Al 2 O 3 、 CaO in an amount of 7.9-12.0 mass% 8.0-12.5% ​​by mass of MgO, 0-1.0% by mass of Na 2O、 K in an amount of 0-0.5 mass% 2 O、 Li in an amount of 0.4 to 1.0 mass% 2 O, and 0.2 to 1.5 mass% of TiO 2 A glass composition comprising (R2)(MgO+Al 2 O 3 +Li 2 O) / (CaO+SiO 2 +Na 2 O+K 2 O) is greater than 0.46, and the mass percentage ratio (R3) (MgO / SiO) 2 A glass composition having a coefficient of at least 0.19 and a fiberization temperature of 1,300°C or lower.

[12] SiO2 between 57.1% by mass and less than 59% by mass 2 The glass composition according to

[11] , comprising:

[13] The glass composition according to

[11] , comprising 7.9% by mass to less than 9.0% by mass of CaO.

[14] SiO 2 、Al 2 O 3 The glass composition according to

[11] , wherein the total amount of MgO and CaO is at least 98% by mass and less than 99.5% by mass.

[15] The glass composition according to

[11] , which does not contain rare earth element oxides.

[16] Al (more than 20% by mass to 21% by mass) 2 O 3 The glass composition according to

[11] , comprising:

[17] 0.45 mass% to 0.8 mass% Li 2 The glass composition according to

[11] above, comprising O.

[18] 0.1 to 0.8 mass% Na 2 The glass composition according to [1] above, comprising O.

[19] A mass percentage ratio (R1) (MgO + Al) of at least 0.47 2 O 3 ) / (SiO 2 The glass composition according to

[11] above, comprising +CaO).

[20] 57.0 to 62.0 mass% of SiO 2 、 20.0-25.0% by mass of Al 2 O 3 、 CaO in an amount of 7.0-9.0 mass% 8.0-12.5% ​​by mass of MgO, 0-1.0% by mass of Na 2 O、 K in an amount of 0-0.5 mass% 2 O、 Li in an amount of 0.4 to 1.0 mass% 2 O, and 0.2 to 1.5 mass% of TiO 2 Glass fibers formed from a glass composition containing (R1)(MgO+Al 2 O 3 ) / (SiO 2 The ratio of (+CaO) is at least 0.47, and the mass percentage ratio (R3) (MgO / SiO) is at least 0.47. 2 Glass fiber having a fiberization temperature of 1,300°C or less and an elastic modulus between 90 GPa and 92 GPa, wherein the ratio is at least 0.19, the glass composition has an elasticity temperature of 1,300°C or less, and the elastic modulus is between 90 GPa and 92 GPa.

[21] At least 2.6 g / cm³ 3 The glass fiber according to

[20] having the density.

[22] The composition contains 57.1% to less than 59% by mass of SiO 2 Glass fibers as described in

[20] above, including the glass fibers described in

[20] above.

[23] The glass fiber according to

[20] , wherein the composition contains 7.9% by mass to less than 9.0% by mass of CaO.

[24] SiO 2 、Al 2 O 3 The glass fiber according to

[20] , wherein the total amount of MgO and CaO is at least 98% by mass and less than 99.5% by mass.

[25] The step of preparing the molten composition described in [1] above, and Step 1: Stretch the molten composition from the orifice to form continuous glass fibers. A method for forming continuous glass fibers containing [a specific material].

[26] Polymer matrix, and 57.0-62.0% by mass of SiO 2 、 20.0-25.0% by mass of Al 2 O 3 、 CaO in an amount of 7.0-9.0 mass% 8.0-12.5% ​​by mass of MgO, 0-1.0% by mass of Na 2 O、 K in an amount of 0-0.5 mass% 2 O、 Li in an amount of 0.4 to 1.0 mass% 2 O, and 0.2 to 1.5 mass% of TiO 2 Multiple glass fibers formed from a glass composition containing (R1)(MgO+Al 2 O 3 ) / (SiO 2 The ratio of (+CaO) is at least 0.47, and the mass percentage ratio (R3) (MgO / SiO) is at least 0.47. 2 ) is at least 0.19, the glass composition has a fiberization temperature of 1,300°C or less, and the glass fibers have an elastic modulus between 90 GPa and 92 GPa, and a plurality of glass fibers Reinforced composite products, including those mentioned above.

[27] The reinforced composite product described in

[26] , in the form of a wind blade.

Claims

1. 57.0–62.0 mass% of SiO 2 , 20.0 to 25.0 mass% of Al 2 O 3 , CaO in an amount of 7.0 to 9.0 mass% 8.0 to 12.5% ​​by mass of MgO, 0 to 1.0% by mass of Na 2 O, K in an amount of 0 to 0.5 mass% 2 O, Li in an amount of 0.2 to 1.0 mass% 2 O, and A glass composition containing TiO in an amount of 0.2 to 1.5% by mass 2 where the mass percentage ratio (R1) (MgO + Al 2 O 3 ) / (SiO 2 + CaO) is at least 0.47, and the mass percentage ratio (R3) (MgO / SiO 2 ) is at least 0.19, and having a fiberization temperature of 1,300 °C or lower, a glass composition.

2. The glass composition according to claim 1, comprising 7.9% by mass to less than 9.0% by mass of CaO.

3. SiO 2 Al 2 O 3 The glass composition according to claim 1 or 2, wherein the total amount of MgO and CaO is at least 98% by mass and less than 99.5% by mass.

4. A glass composition according to any one of claims 1 to 3, which does not contain rare earth element oxides.

5. More than 20% by mass to 21% by mass of Al 2 O 3 A glass composition according to any one of claims 1 to 4, comprising:

6. 0.4 mass% to 0.8 mass% Li 2 A glass composition according to any one of claims 1 to 5, comprising O.

7. B 2 O 3 A glass composition according to any one of claims 1 to 6, comprising less than 1.0% by mass of the following.

8. Mass percentage ratio greater than 0.46 (R2) (MgO + Al 2 O 3 +Li 2 O) / (CaO+SiO 2 +Na 2 O+K 2 A glass composition according to any one of claims 1 to 7, comprising O).

9. A glass fiber formed from the glass composition according to any one of claims 1 to 8, wherein the glass fiber has an elastic modulus between 90 GPa and 92 GPa.

10. A step of preparing a molten glass composition according to any one of claims 1 to 9, and Step 1: Stretch the molten glass composition from the orifice to form continuous glass fibers. A method for forming continuous glass fibers, including [a specific component].

11. Polymer matrix, and A plurality of glass fibers formed from the glass composition according to any one of claims 1 to 9. A reinforced composite product including, A reinforced composite product wherein the glass fibers have an elastic modulus between 90 GPa and 92 GPa.

12. SiO2 in an amount greater than 57.0% to 62.0% by mass 2 , 20.0 to 25.0 mass% of Al 2 O 3 , CaO in an amount of 7.0 to 11.5 mass% 8.0 to 12.5% ​​by mass of MgO, 0 to 1.0% by mass of Na 2 O, K in an amount of 0 to 0.5 mass% 2 O, Li in an amount of 0.2 to 0.8 mass% 2 O, and TiO in an amount of 0.2 to 1.5 mass% 2 A glass composition comprising (R2) (MgO + Al 2 O 3 +Li 2 O) / (CaO+SiO 2 +Na 2 O+K 2 O) is greater than 0.46, and the mass percentage ratio (R3) (MgO / SiO) 2 A glass composition having a ratio of at least 0.19 and a fiberization temperature of 1,300°C or lower.

13. The glass composition according to claim 12, comprising 7.9% by mass to less than 9.0% by mass of CaO.

14. SiO 2 Al 2 O 3 The glass composition according to claim 12 or 13, wherein the total amount of MgO and CaO is at least 98% by mass and less than 99.5% by mass.

15. More than 20% by mass to 21% by mass of Al 2 O 3 A glass composition according to any one of claims 12 to 14, comprising:

16. 0.4 mass% to 0.8 mass% Li 2 A glass composition according to any one of claims 12 to 15, comprising O

17. The mass percentage ratio (R1) (MgO + Al) is at least 0.

47. 2 O 3 ) / (SiO 2 A glass composition according to any one of claims 12 to 16, comprising (+ CaO).

18. A glass fiber formed from the glass composition according to any one of claims 12 to 17, wherein the glass fiber has an elastic modulus between 90 GPa and 92 GPa.

19. 57.0–62.0 mass% of SiO 2 , 20.0 to 25.0 mass% of Al 2 O 3 , CaO in an amount of 7.0 to 9.0 mass% 8.0 to 12.5% ​​by mass of MgO, 0 to 1.0% by mass of Na 2 O, K in an amount of 0 to 0.5 mass% 2 O, Li in an amount of 0.4 to 1.0 mass% 2 O, and TiO in an amount of 0.2 to 1.5 mass% 2 Glass fibers formed from a glass composition containing (R1) (MgO + Al 2 O 3 ) / (SiO 2 The ratio of (+CaO) is at least 0.47, and the mass percentage ratio (R3) (MgO / SiO) 2 A glass fiber having an elastic modulus between 90 GPa and 92 GPa, wherein the glass composition has a fiberization temperature of 1,300°C or lower, and the elastic modulus is between 90 GPa and 92 GPa.

20. At least 2.6 g / cm³ 3 The glass fiber according to claim 19, having the density.

21. The composition contains 57.1% to less than 59% by mass of SiO 2 The glass fiber according to claim 19, including the glass fiber described in claim 19.

22. The glass fiber according to claim 19, wherein the composition contains 7.9% by mass to less than 9.0% by mass of CaO.

23. SiO 2 Al 2 O 3 The glass fiber according to claim 19, wherein the total amount of MgO and CaO is at least 98% by mass and less than 99.5% by mass.

24. The steps of preparing the molten composition described in claim 1, and Step 1: Stretch the molten composition from the orifice to form continuous glass fibers. A method for forming continuous glass fibers containing [a specific material].

25. Polymer matrix, and 57.0–62.0 mass% of SiO 2 , 20.0 to 25.0 mass% of Al 2 O 3 , CaO in an amount of 7.0 to 9.0 mass% 8.0 to 12.5% ​​by mass of MgO, 0 to 1.0% by mass of Na 2 O, K in an amount of 0 to 0.5 mass% 2 O, Li in an amount of 0.4 to 1.0 mass% 2 O, and TiO in an amount of 0.2 to 1.5 mass% 2 A plurality of glass fibers formed from a glass composition containing (R1) (MgO + Al 2 O 3 ) / (SiO 2 The ratio of (+CaO) is at least 0.47, and the mass percentage ratio (R3) (MgO / SiO) 2 ) is at least 0.19, the glass composition has a fiberization temperature of 1,300°C or less, and the glass fibers have an elastic modulus between 90 GPa and 92 GPa, and there are multiple glass fibers Reinforced composite products, including those mentioned above.

26. The reinforced composite product according to claim 25, in the form of a wind blade.

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