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EP-4393894-B1 - GLASS FIBER AND COMPOSITION FOR GLASS FIBER

EP4393894B1EP 4393894 B1EP4393894 B1EP 4393894B1EP-4393894-B1

Inventors

  • NAKAMURA, AYA

Dates

Publication Date
20260506
Application Date
20221228

Claims (7)

  1. A glass composition for glass fibers, comprising, in mass%: SiO 2 59.5 to 62.5%; Al 2 O 3 19 to 21.2%; B 2 O 3 0 to 0.5%; MgO 16 to 18%; CaO 0 to 1.5%; Li 2 O 0.1 to 0.8%; Na 2 O 0 to 0.2%; K 2 O 0 to 0.1%; TiO 2 0 to 5%; ZrO 2 0 to 5%; ZnO 0 to 1.5%; and F 2 0 to 0.1% characterized in that ΔT determined by subtracting a devitrification temperature TL from a temperature T3 at which a viscosity becomes 10 3 dPa•s is a positive value, and ΔW 1 = {(Wa - Wb)/Wa} × 100 is 0.1 mass% or less, Wa being a number of gram before and Wb being a number of gram after a monofilament having a diameter of 15 µm and a length of 20 mm, formed from the glass composition, is immersed for 60 minutes in 80 mL of sulfuric acid having a specific gravity of 1.2 and a temperature of 99°C, the numbers of grams being taken in accordance with the specific gravity of the glass of the monofilament.
  2. The glass composition according to claim 1, wherein a sum (SiO 2 + TiO 2 + ZrO 2 ) of a SiO 2 content, a TiO 2 content, and a ZrO 2 content is 60% or more in mass%.
  3. The glass composition according to claim 1, wherein a sum (TiO 2 + ZrO 2 ) of a TiO 2 content and a ZrO 2 content is 0.1% or more in mass%.
  4. The glass composition according to claim 1, comprising less than 0.1 mass% of impurities of Y 2 O 3 and La 2 O 3 .
  5. The glass composition according to claim 1, having a Young's modulus of 97 GPa or more.
  6. A glass fiber comprising the glass composition according to any one of claims 1 to 5.
  7. The glass fiber according to claim 6, being in a form of at least one selected from the group consisting of a strand, a roving, a yarn, a cloth, a chopped strand, glass wool, and a milled fiber.

Description

TECHNICAL FIELD The present invention relates to a glass fiber and a glass composition suitable for glass fibers. BACKGROUND ART Although many of glass fibers in practical use are formed of a glass composition having a Young's modulus of 90 GPa or less, glass compositions having a Young's modulus of more than 90 GPa are also known. For example, Patent Literature 1 discloses a glass composition including a large amount of rare-earth oxides. The total content of Y2O3 and La2O3 in the glass composition of Patent Literature 1 is in the range of 20 to 60 weight%. However, a high rare-earth oxide content increases the manufacturing cost. Taking this into account, Patent Literature 2 discloses a technique by which the Young's modulus of a glass composition is improved without a large amount of rare-earth oxides. The glass composition of Patent Literature 2 includes 15 to 30% MgO in mol% as a component for improving the Young's modulus. CITATION LIST Patent Literature Patent Literature 1: WO 2006/057405 A1Patent Literature 2: JP 6391875 B1 A basic composition comprising SiO2, Al2O3, and MgO, with 2.35 to 3.40 weight ratio of SiO2/Al2O3, 1.25 to 2.30 weight ratio of Al2O3/MgO, and the sum of SiO2, Al2O3, and MgO being ≥ 98 weight% on the basis of the whole weight is shown in JP 2004-115368 A. Chen Chunyu et al.: "Structural and dynamic properties of MgO-Al2O3-SiO2 glasses from molecular dynamics simulations and NMR", Ceramics International, vol. 48, no. 15, 1 August 2022, pages 22444-22450, DOI: 10.1016/j.ceramint.2022.04.259, and Schreyer W. et al.: Compositions and structural states of anhydrous MG-cordierites: A re-investigation of the central part of the system MgO-Al2O3-SiO2", Journal of Petrology, Clarendon Press, Oxford, GB, vol. 2, no. 3, 1 January 1961, pages 324-406, ISSN: 0022-3530, show a magnesium aluminosilicate glass. SUMMARY OF INVENTION Technical Problem Patent Literature 2 fails to specifically discuss the acid resistance of the glass composition. Additionally, it is desirable that mass production of a glass fiber and other shaped glass products can continue without devitrification. It is therefore an object of the present invention to provide a glass fiber having a high Young's modulus and a high acid resistance and suitable for mass production and a glass composition suitable for manufacturing such a glass fiber. Solution to Problem The present invention is defined in the claims and also provides a glass fiber including the glass composition for glass fibers according to the present invention. Advantageous Effects of Invention The present invention provides a glass fiber having a good balance between the acid resistance, the Young's modulus, and the mass productivity and a glass composition for glass fibers, the glass composition being suitable for such a glass fiber. DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described hereinafter. The following description is not intended to limit the present invention to particular embodiments. Herein, the content of each component in a glass composition below is in mass%, and mass% is basically represented by "%". Herein, being "substantially free of" a component means that the content of the component is less than 0.1 mass%, less than 0.05 mass%, less than 0.01 mass%, less than 0.005 mass%, even less than 0.003 mass%, or, in some cases, less than 0.001 mass%. The adverb "substantially" is intended to mean that a small amount impurities such as those derived from a glass raw material, a manufacturing apparatus, and the like may be contained. The term "alkali metal oxides" means Li2O, Na2O, and K2O, and is sometimes referred to as R2O. The upper and lower limits of each of the following contents can be arbitrarily combined in both cases where the upper and lower limits are individually specified and where the upper and lower limits are expressed as a range. [Glass composition] <Components> Components that can form the glass composition of the present embodiment will be each described hereinafter. (SiO2) SiO2 is a component that forms a glass network, and is also a component that adjusts the devitrification temperature and the viscosity during glass forming and that improves the acid resistance. A SiO2 content is 59.5 to 62.5%. The lower limit of the SiO2 content may be 59.6% or more, 59.8% or more, or even 60% or more. The upper limit of the SiO2 content may be 62.3% or less, 62% or less, 61.8%, or even 61.5% or less. The SiO2 content may be 59.6 to 61.5%. (Al2O3) Al2O3 is a component that adjusts the devitrification temperature and the viscosity during glass forming and that contributes to improvement of the water resistance of the resulting glass. An Al2O3 content is 19 to 21.2%. The lower limit of the Al2O3 content may be, for example, 19.3% or more, 19.5% or more, 19.7% or more, or even 20% or more. The upper limit of the Al2O3 content may be 21% or less, 20.8% or less, or even 20.6% or less. The Al2O3 content may be 19.7 to 20