Low-Dielectric Glass Composition, Fiber, and Article

Abstract

Disclosed are glass compositions and glass fibers having low dielectric constants and low loss factors that may be suitable for use in electronic applications and articles. The glass fibers and compositions of the present invention may contain 48.0 to 57.0 weight percent SiO2, 15.0 to 26.0 weight percent BO, 12.0 to 18.0 weight percent AlO, greater than 3.0 to 8.0 weight percent PO, greater than 0.25 to 7.00 weight percent CaO, 5.0 weight percent or less MgO, and 6.0 weight percent or less TiO. Furthermore, the glass compositions have a glass viscosity of 1000 poise at temperatures greater than 1350°C and a liquidus temperature greater than 1100°C.

Description

Technical Field

[0001] [Related Applications] This application claims the benefit of priority under PCT Article 8 of U.S. Patent Application No. 16 / 732,825, filed on January 2, 2020, and U.S. Patent Application No. 16 / 792,658, filed on February 17, 2020. These applications are divisional applications of U.S. Patent Application No. 16 / 474,287, filed on June 27, 2019, as a national stage application of International Application No. PCT / US17 / 67785, filed on December 21, 2017, which claims the priority of U.S. Patent Application No. 62 / 439,755, filed on December 28, 2016. The content of the above applications is hereby incorporated by reference in its entirety as if fully set forth herein.

[0002] The present invention relates to glass compositions and fibers. More particularly, the present invention relates to glass compositions and fibers having a low dielectric constant and a low loss factor. Further, the glass fibers of the present invention are preferably suitable for use related to electronic devices such as reinforcement of printed circuit laminates.

Background Art

[0003] Modern electronic devices generally include printed circuit boards reinforced with glass fibers. Many modern electronic devices such as mobile or fixed wireless telephones, computers, smartphones, tablets, etc. have high processing speeds and electronic systems operating at high frequencies or ultra-high frequencies. When glass is exposed to such high-frequency or ultra-high-frequency electromagnetic fields, the glass absorbs at least some of the energy and converts the absorbed energy into heat. The energy converted into heat by the glass is called dielectric loss energy. This dielectric loss energy is proportional to the "dielectric constant" and "dielectric tangent" of the glass composition as shown by the following equation: W = k·f·v 2 ·ε·(tan δ)

[0004] In the above formula, "W" is the dielectric loss energy in the glass, "k" is a constant, "f" is the frequency, and "v 2 " is the electric field gradient, "ε" is the dielectric constant, and "tan δ" is the dielectric tangent. The dielectric tangent (tan δ) is dimensionless and is often referred to in the art by the following synonyms: "loss rate" or more generally "loss factor" (Df). As shown in the above formula, the dielectric loss energy "W" increases with an increase in the dielectric constant and dielectric tangent (loss factor, Df) of the glass and / or an increase in the frequency.

[0005] Two types of glass fibers commonly used for strengthening printed circuit boards are E-glass and D-glass. However, E-glass has a relatively high dielectric constant in the range of about 6.1 and a relatively high loss factor in the range of about 38×10 -4 at a frequency of about 10 GHz at room temperature. Therefore, since E-glass can cause relatively high dielectric losses, E-glass is an insufficient reinforcing material for printed circuit boards with higher density electronic components and higher processing speeds. On the other hand, D-glass has a relatively low dielectric constant and loss factor. However, D-glass has a relatively high melting temperature, relatively low processability, relatively low mechanical properties, and relatively low water resistance. In addition, D-glass may have insufficient adhesion to epoxy resins and generally has defects in the form of veins and air bubbles. Therefore, neither E-glass nor D-glass is ideally suitable for use as a reinforcing fiber in high-speed printed circuit boards, and neither is very suitable for circuit boards operating at high frequencies or ultra-high frequencies from about 100 MHz to about 18 GHz.

[0006] Conventional attempts to provide glass formulations suitable for electronic devices include Patent Document 1 of Mori, Patent Document 2 of Creux, Patent Document 3 of Tamura, Patent Document 4 of Tamura, Patent Document 5 of Kuhn, Patent Document 6 of Yoshida, Patent Document 7 of Sawanoi, and Patent Document 8 of Zhang.

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] U.S. Patent No. 5,958,808 [Patent Document 2] U.S. Patent Application Publication No. 2004 / 0175557 [Patent Document 3] U.S. Patent No. 6,309,990 [Patent Document 4] U.S. Patent No. 6,846,761 [Patent Document 5] International Publication No. 2010 / 011701 [Patent Document 6] U.S. Patent Application Publication No. 2011 / 0281484 [Patent Document 7] U.S. Patent No. 8,679,993 [Patent Document 8] Chinese Patent Application Publication No. 103351102 [Summary of the Invention]

[0008] In one aspect of the present invention, there is provided a glass composition comprising 48.0 wt% to 57.0 wt% of SiO 2 and 15.0 wt% of B 2 O 3 to 26.0 wt% of B 2 O 3 and 12.0 wt% of Al 2 O 3 to 18.0 wt% of Al 2 O 3 and more than 3.0 wt% to 8.0 wt% of P 2 O 5 and more than 0.25 wt% to 7.0 wt% of CaO, 5.0 wt% or less of MgO, and 6.0 wt% or less of TiO 2 and having a glass viscosity of 1000 poises at a temperature above 1350 °C and a liquidus temperature above 1100 °C.

[0009] In one embodiment of the present invention, the glass composition comprises 49.0 wt% to 56.5 wt% of SiO 2and B of 15.5 wt% to 25.5 wt% 2 O 3 and Al 2 O 3 of 12.5 wt% to 17.50 wt% and P 2 O 5 of more than 3.0 wt% to 7.5 wt%, CaO of more than 0.25 wt% to 6.5 wt%, MgO of 4.5 wt% or less, and TiO 2 of 5.5 wt% or less, and further includes them.

[0010] In one embodiment of the present invention, the glass composition contains SiO 2 of 50.0 wt% to 56.0 wt%, and B 2 O 3 of 16.0 wt% to 25.0 wt%, and Al 2 O 3 of 13.0 wt% to 17.0 wt%, and P 2 O 5 of more than 3.0 wt% to 7.0 wt%, CaO of more than 0.25 wt% to 6.0 wt%, MgO of 4.0 wt% or less, and TiO 2 of 5.0 wt% or less, and further includes them.

[0011] In one embodiment of the present invention, the composition contains SiO 2 of 49.0 wt% or more, SiO 2 of 56.5 wt% or less, B 2 O 3 of 15.5 wt% or more, B 2 O 3 of 25.5 wt% or less, Al 2 O 3 of 17.50 wt% or less, P 2 O 5 of 7.0 wt% or less, CaO of 6.5 wt% or less, MgO of 4.5 wt% or less, and / or TiO 2 of 5.5 wt% or less, and further includes one or more of them.

[0012] In one embodiment of the present invention, the composition contains 50.0 wt% or more of SiO 2 and 56.0 wt% or less of SiO 2 16.0 wt% or more of B 2 O 3 and 25.0 wt% or less of B 2 O 3 17.0 wt% or less of Al 2 O 3 7.0 wt% or less of P 2 O 5 and / or one or more of 6.0 wt% or less of CaO, 4.0 wt% or less of MgO, and 5.0 wt% or less of TiO 2 further included.

[0013] In one embodiment of the present invention, the composition has a liquid phase temperature above 1100 °C.

[0014] In one embodiment of the present invention, the composition has a liquid phase temperature above 1150 °C.

[0015] In one embodiment of the present invention, the composition has a liquid phase temperature above 1200 °C.

[0016] In one embodiment of the present invention, the composition has a glass viscosity of 1000 poises at a temperature above 1355 °C.

[0017] In one embodiment of the present invention, the composition has a glass viscosity of 1000 poises at a temperature above 1360 °C.

[0018] In one embodiment of the present invention, the glass fiber is formed from the above glass composition.

[0019] In one embodiment of the present invention, the glass fiber has a dielectric constant of 6 or less and / or a loss factor of 38×10 -4 or less at a frequency of 10 GHz at room temperature.

[0020] In one embodiment of the present invention, the glass fiber has a dielectric constant of 4.60 or less and / or a loss factor of 30×10 -4 or less at a frequency of 10 GHz at room temperature.

[0021] In one embodiment of the present invention, the glass fiber has a dielectric constant of 4.55 or less and / or a loss factor of 25×10 -4 or less at a frequency of 10 GHz at room temperature.

[0022] In one embodiment of the present invention, the glass composition crystallizes into aluminoborate mullite crystals and has a unique network structure that is easy to form.

[0023] In one embodiment of the present invention, there is provided a method for providing continuously manufacturable low-dielectric glass fibers, including the steps of supplying any of the glass compositions described herein to a melting zone of a glass melting furnace, heating the composition to a forming temperature above the liquidus temperature, and continuously spinning the molten glass to produce glass fibers with a low dielectric constant and a low loss factor.

[0024] In one aspect of the present invention, 48.0 wt% to 57.0 wt% of SiO 2 and 15.0 wt% to 26.0 wt% of B 2 O 3 and 12.0 wt% to 18.0 wt% of Al 2 O 3 and more than 3.0 wt% to 8.0 wt% of P 2 O 5 and more than 0.25 wt% to 7.00 wt% of CaO and 5.0 wt% or less of MgO and 6.0 wt% or less of TiO 2 and further provided are low-dielectric glass fibers formed from a glass composition having a glass viscosity of 1000 poises at a temperature above 1350 °C and a liquidus temperature above 1100 °C.

[0025] In one embodiment of the present invention, the glass composition contains 49.0 wt% to 56.5 wt% of SiO 2 and 15.5 wt% to 25.5 wt% of B 2 O 3 and 12.5 wt% to 17.50 wt% of Al 2 O 3 and more than 3.0 wt% to 7.5 wt% of P 2 O 5 and more than 0.25 wt% to 6.5 wt% of CaO, 4.5 wt% or less of MgO, and 5.5 wt% or less of TiO 2 and further contains the same.

[0026] In one embodiment of the present invention, the glass composition contains 50.0 wt% to 56.0 wt% of SiO 2 and 16.0 wt% to 25.0 wt% of B 2 O 3 and 13.0 wt% to 17.0 wt% of Al 2 O 3 and more than 3.0 wt% to 7.0 wt% of P 2 O 5 and more than 0.25 wt% to 6.0 wt% of CaO, 4.0 wt% or less of MgO, and 5.0 wt% or less of TiO 2 and further contains the same.

[0027] In one embodiment of the present invention, the glass composition contains 49.0 wt% or more of SiO 2 , 56.5 wt% or less of SiO 2 , 15.5 wt% or more of B 2 O 3 , 25.5 wt% or less of B 2 O 3 , 17.50 wt% or less of Al 2 O 3 , 7.0 wt% or less of P 2 O 5, CaO of 6.5 weight percent or less, MgO of 4.5 weight percent or less, and / or TiO of 5.5 weight percent or less 2 further includes one or more of them.

[0028] In one embodiment of the present invention, the glass composition contains SiO of 50.0 weight percent or more 2 , SiO of 56.0 weight percent or less 2 , B of 16.0 weight percent or more 2 O 3 , B of 25.0 weight percent or less 2 O 3 , Al of 17.0 weight percent or less 2 O 3 , P of 7.0 weight percent or less 2 O 5 , CaO of 6.0 weight percent or less, MgO of 4.0 weight percent or less, and / or TiO of 5.0 weight percent or less 2 further includes one or more of them.

[0029] In one embodiment of the present invention, the glass composition has a liquid phase temperature exceeding 1100 °C.

[0030] In one embodiment of the present invention, the glass composition has a liquid phase temperature exceeding 1150 °C.

[0031] In one embodiment of the present invention, the glass composition has a liquid phase temperature exceeding 1200 °C.

[0032] In one embodiment of the present invention, the glass composition has a glass viscosity of 1000 poises at a temperature exceeding 1355 °C.

[0033] In one embodiment of the present invention, the glass composition has a glass viscosity of 1000 poises at a temperature exceeding 1360 °C.

[0034] In one embodiment of the present invention, the glass fiber has a dielectric constant of 6 or less and / or a loss coefficient of 38×10 -4 or less at a frequency of 10 GHz at room temperature.

[0035] In one embodiment of the present invention, the glass fiber has a dielectric constant of 4.60 or less and / or a loss factor of 30×10 -4 or less at a frequency of 10 GHz at room temperature.

[0036] In one embodiment of the present invention, the glass fiber has a dielectric constant of 4.55 or less and / or a loss factor of 25×10 -4 or less at a frequency of 10 GHz at room temperature.

[0037] In one embodiment of the present invention, the glass fiber is crystallized into aluminoborate mullite crystals and is formed from a glass composition having a unique network structure that is easy to form it.

[0038] The present invention also includes glass fiber-reinforced articles such as printed circuit boards incorporating the glass fiber of the present invention. Further, the present invention includes products incorporating glass fibers as disclosed above, and the products can be printed circuit boards, woven fabrics, non-woven fabrics, unidirectional fabrics, chopped strands, chopped strand mats, composite materials, and communication signal transport media.

[0039] The present invention includes a method for providing continuously manufacturable low-dielectric glass fibers. The method may include supplying a glass composition as disclosed herein to a melting zone of a glass melting furnace, heating the composition to a forming temperature above the liquidus temperature, and continuously spinning the molten glass to produce glass fibers with a low dielectric constant and a low loss factor.

[0040] Some embodiments of the present invention are described herein by way of example with reference to the accompanying drawings. Referring particularly to the drawings in detail, it is emphasized that the details shown are by way of example and not necessarily to scale, and are for the purpose of illustrative discussion of embodiments of the present invention. In this regard, the description using the drawings will clarify to those skilled in the art how embodiments of the present invention can be implemented.

Brief Description of the Drawings

[0041]

Figure 1

DETAILED DESCRIPTION OF THE INVENTION

[0042] The present invention relates to glass compositions and fibers preferably having a low dielectric constant value and a low loss factor (also referred to herein as tan δ). The glass fibers of the present invention are preferably suitable for applications related to electronic devices and systems operating at high processing speeds and / or high frequencies, such as mobile or fixed wireless telephones, computers, smartphones, tablets, etc. The glass fibers of the present invention preferably exhibit a lower dielectric constant and loss factor than E-glass, but have better processing characteristics than D-glass. Although mainly described from the perspective of its applications related to electronic devices and the reinforcement of printed circuit boards, other applications and advantages of the glass compositions and glass fibers of the present invention can be contemplated without departing from the spirit and scope of the present invention. The present invention also discloses glass fiber-reinforced articles, products incorporating glass fibers, such as printed circuit boards, woven fabrics, non-woven fabrics, unidirectional fabrics, chopped strands, chopped strand mats, composite materials and communication signal transmission media, and methods for providing continuously manufacturable low-dielectric glass fibers.

[0043] The compositions of the present invention generally include the following silicon oxide (SiO 2 )), boron oxide (B 2 O 3 ), aluminum oxide (Al 2 O 3 ), calcium oxide (CaO), phosphorus oxide (P 2 O 5 ), magnesium oxide (MgO) and titanium oxide (TiO 2) and is composed of one or more oxides. Additional oxides may be present without departing from the spirit and scope of the present invention, as discussed below. The compositions of the present invention, in some embodiments, have a liquidus temperature above 1100 °C and a glass viscosity of 1000 poises at a temperature (T log3) above 1350 °C. Further, the glass fibers of the present invention preferably have a dielectric constant of 6 or less and / or a loss factor of 38×10 -4 or less at a frequency of 10 GHz at room temperature. Advantageously, the composition of the present glass preferably has the ability to continuously spin because of its positive difference (ΔT 3 ) between the T log3 viscosity temperature and the liquidus temperature.

[0044] Unless otherwise specified, the following terms used in this specification and the claims have the meanings indicated below.

[0045] As used herein, the term "liquidus" is given its normal and conventional meaning, including the temperature (T liq ) at which equilibrium exists between the liquid glass and its primary crystalline phase. At all temperatures above the liquidus, the glass melt has no crystals of its primary crystalline phase, and at temperatures below the liquidus, crystals can form in the melt. Thus, the liquidus temperature gives a useful lower limit temperature above which it is possible to continuously spin the glass.

[0046] The term "spinning temperature" or "T log3 viscosity temperature" is understood to mean the temperature (denoted as T log3) at which the glass has a viscosity equal to 1000 poises.

[0047] As used herein, "ΔT 3The term "Delta T", also referred to as such, is given its ordinary and customary meaning in the art, generally including the difference between the spinning temperature and the liquidus, and thus is a spinning characteristic of the glass composition. The greater the Delta T, the greater the process flexibility during the formation of glass fibers, and the lower the likelihood of devitrification (crystallization) of the glass melt during melting and spinning. Generally, the greater the Delta T, among other things, the longer the bushing life, resulting in a wider fiber-forming process window and thus lower production costs of glass fibers.

[0048] The term "fiber" refers to an elongated object whose length dimension is greater than the lateral dimensions of its width and thickness. Thus, the term "fiber" includes monofilaments, multifilaments, ribbons, strips, staples, and other forms of fibers having regular or irregular cross-sections, chopped, cut, or discontinuous fibers, etc. Fibers and filaments are used interchangeably herein.

[0049] The term "E glass" is used according to its meaning described in ASTM D-578.

[0050] The term "D glass" refers to a glass composition having the properties defined herein.

[0051] "Low dielectric constant" means a glass fiber having a dielectric constant lower than that of E glass. By way of example, E glass has a dielectric constant of about 6.1 at a frequency of 10 GHz at room temperature.

[0052] "Low loss factor" means a glass fiber having a loss factor lower than that of E glass. By way of example, E glass has a loss factor of about 38×10 -4 at a frequency of about 10 GHz at room temperature.

[0053] "Low dielectric glass fiber" means a glass fiber having a low dielectric constant and a low loss factor as defined herein.

[0054] Generally, glass that has been melted at a sufficiently high temperature for a sufficiently long time tends to be chemically and structurally homogeneous, i.e., there tend to be no regions of different chemical composition or atomic arrangement. Further, the minimum homogeneity required for continuous spinning is a molten state in which the inhomogeneities are too small to interfere with the spinning process, so that fibers can be formed stably and continuously. Efficient spinning requires a consistent quality of glass melt with respect to the viscosity of the liquid. Variations in viscosity impede flow and cause fiber breakage during formation. Defects in the glass melt are typically caused by either unmelted batch material (stones), glass that has been insufficiently melted or homogenized (veins / cords), and devitrification products (crystals formed at temperatures below liq liq the crystallization temperature). In the course of their research, the inventors have found that glasses of this glass family tend to undergo liquid-liquid immiscibility (glass phase separation) when cooled from high temperatures. Phase separation is the tendency for a homogeneous liquid at high temperature to thermodynamically separate into two different glasses upon cooling, and the composition, liquid structure, and related properties often differ significantly. Further, phase-separated glasses can exhibit discontinuous viscosity behavior rather than being continuous as a function of temperature, and thus, the phase-separated regions of the melt can interfere with stable fiber formation.

[0055] In an attempt to understand and control this phase separation tendency, the inventors utilized the following method to characterize the stability of the glass melt of each composition during and after melting. After the end of each melting cycle, the crucible was removed from the furnace and allowed to cool naturally until it reached a temperature below the glass transition temperature T g g Glass that was not considered stable exhibited varying degrees of opalescence (light scattering) in the cooled state. Each melt was ranked on a scale of 1 to 6 (the "melt instability index") from no opalescence (1, very stable) to 6 (least stable, opaque). These rankings were sufficient to help distinguish between regions of good glass-forming stability and regions of insufficient or unstable glass-forming behavior. Glasses with high melt instability index values (greater than 4) are expected to be difficult to spin in a continuous / stable manufacturing process. References to these melt instability index values are made throughout this specification, including in the tables of test results below.

[0056] There is provided a glass composition for forming glass fibers which is preferably suitable for electronic applications and use in articles and which can preferably be economically formed into glass fibers by continuous spinning.

[0057] In some embodiments of the present invention, the glass fibers comprise 45 wt% to 58 wt% silicon dioxide (SiO 2(Also referred to herein as silica) is included in the composition. Alternatively, the silicon dioxide content may be from 45.5 wt% to 57.5 wt%. Further alternatively, the silicon dioxide content may be from 46 wt% to 57 wt%. In a further embodiment, the silicon dioxide content may be less than 56.75 wt%. In yet a further embodiment, the silicon dioxide content may be less than 56.50 wt%. When the percentage of silicon dioxide is outside this range, the viscosity of the glass and spinning are typically affected. For example, when the silicon dioxide is less than 45 wt% of the total composition of the glass fiber, the viscosity of the glass may decrease to the extent that devitrification (crystallization) occurs during spinning. In contrast, when the silicon dioxide is more than 58 wt% of the total composition of the glass fiber, the viscosity of the glass may become too high, making melting, homogenization and refining more difficult. Therefore, the silica content is preferably from 45 wt% to 58 wt% of the total composition of the glass. Further, when combined with other components defined herein, a silica content of from 45.00 wt% to 58.00 wt% typically results in glass fibers having not only a desirable low dielectric constant but also a low loss factor. In one embodiment of the glass fiber and / or glass composition of the present invention, the silica content is at least 45.50 wt%. Alternatively, the silica content is at least 46.00 wt%. In another embodiment of the glass fiber and / or glass composition of the present invention, the silica content is 57.50 wt% or less. Alternatively, the silica content is 57.00 wt% or less. Further alternatively, the silica content is 56.75 wt% or less. In another embodiment, the silica content is 56.50 wt% or less.

[0058] Notwithstanding the above, the inventors have found that the glass fiber has a silicon dioxide (SiO 2) having a composition, a certain surprisingly useful and / or effective formulation was identified. Alternatively, the silicon dioxide content may be from 49 wt% to 56.5 wt%. Further alternatively, the silicon dioxide content may be from 50 wt% to 56 wt%. In a further embodiment, the silicon dioxide content may be less than 56.0 wt%. When the percentage of silicon dioxide is outside these ranges, the viscosity and spinning of the glass are typically affected. For example, if the silicon dioxide is less than 48 wt% of the total composition of the glass fiber, the viscosity of the glass may decrease to the extent that devitrification (crystallization) occurs during spinning. In contrast, if the silicon dioxide is more than 57 wt% of the total composition of the glass fiber, the viscosity of the glass may become too high, making melting, homogenization, and refining more difficult. Therefore, the silica content is preferably from 48 wt% to 57 wt% of the total composition of the glass. Also, SiO 2 is useful for controlling the stability of the formulation, and the weight percentage of SiO 2 is also to be understood as being optionally selected for such considerations in combination with the other factors described herein.

[0059] The glass fibers in some embodiments of the present invention include a composition having more than 18 wt% boron oxide (B 2 O 3 ) and up to 26 wt% boron oxide. Alternatively, the boron oxide content may be from 18.5 wt% to 25 wt%. Further alternatively, the boron oxide content may be from 19 wt% to 22 wt%. A high percentage of boron oxide above 26 wt% causes B 2 O 3There is a risk of causing excessive loss, insufficient homogeneity, low strength, and insufficient mechanical properties. When combined with other components defined herein, a boron oxide content of more than 18.00 weight percent and not more than 26.00 weight percent typically results in glass fibers having not only a desirable low dielectric constant but also a low loss factor. In one embodiment of the glass fibers and / or glass compositions of the present invention, the boron oxide content is at least 18.50 weight percent. Alternatively, the boron oxide content is at least 19.00 weight percent. In another embodiment of the glass fibers and / or glass compositions of the present invention, the boron oxide content is not more than 25.00 weight percent. Alternatively, the boron oxide content is not more than 24.00 weight percent.

[0060] Notwithstanding the above, the inventors have identified certain surprisingly useful and / or effective formulations that include compositions in which the glass fibers have from 15 weight percent boron oxide (B 2 O 3 ) to 26 weight percent boron oxide. While B 2 O 3 is advantageous for reducing Df, it is generally understood that too much can cause glass instability in the form of phase separation. Alternatively, the boron oxide content may be from 15.5 weight percent to 25.5 weight percent. Further alternatively, the boron oxide content may be from 16 weight percent to 25 weight percent. A high percentage of boron oxide in excess of 26 weight percent results in B 2 O 3It may cause excessive loss, insufficient homogeneity, insufficient mechanical properties, and instability of the glass in the form of phase separation. Furthermore, a low percentage of boron oxide, such as less than 15 weight percent, may cause insufficient dielectric properties. For this reason, the boron oxide content is preferably 15 weight percent to 26 weight percent of the total composition of the glass. Furthermore, when combined with other components defined herein, a boron oxide content of 15.00 weight percent to 26.00 weight percent generally results in glass fibers having not only a desirable low dielectric constant but also a low loss factor. In one embodiment of the glass fiber and / or glass composition of the present invention, the boron oxide content is at least 16.0 weight percent. Furthermore, alternatively and / or optionally, the boron oxide content is 20.00 weight percent or less. In another embodiment of the glass fiber and / or glass composition of the present invention, the boron oxide content is 25.00 weight percent or less.

[0061] In some embodiments of the present invention, the glass fiber comprises a composition having more than 16 weight percent and up to 23 weight percent of aluminum oxide. Alternatively, the aluminum oxide content may be more than 16 weight percent and up to 22.5 weight percent. Further alternatively, the aluminum oxide content may be more than 16 weight percent and up to 22 weight percent. The percentage of aluminum oxide relative to the total composition of the glass fiber can also affect the viscosity and the spinning process. For example, a high percentage of aluminum oxide, such as more than 23 weight percent, can reduce the melt viscosity and there is a risk of devitrification during spinning. A low percentage of aluminum oxide, such as up to 18 weight percent, can cause phase separation and poor fiber formation. Therefore, the alumina content is preferably more than 16 weight percent and up to 23 weight percent of the total composition of the glass. Further, when combined with other components defined herein, an alumina content of 16.00 weight percent to 23.00 weight percent typically results in glass fibers having not only a desirable low dielectric constant but also a low loss factor. In one embodiment of the glass fiber and / or glass composition of the present invention, the alumina content is up to 22.50 weight percent. Alternatively, the alumina content is up to 22.00 weight percent.

[0062] Aluminum oxide is known to stabilize glasses that tend to phase separate / melt instability. However, at high levels it is also known to increase the tendency towards devitrification / crystallization and thus can negatively affect fiber forming stability with respect to delta T. For example in several respects B 2 O 3 is the exact opposite of Al 2 O 3 in these tendencies, and considering the other components of the described formulations, it is important to find the exact balance between all of them. In view of the above, notwithstanding the ranges previously disclosed herein, the inventors have found that in some embodiments of the present invention, when Al 2 O 3 is present in the range of 12 weight percent to 18 weight percent, Df behavior and Tliq A certain particularly useful and / or effective formulation has been identified that achieves a balance with behavior. In some embodiments of the present invention, Al 2 O 3 is present in the range of 12.5% to 17.5% by weight. In some embodiments of the present invention, Al 2 O 3 is present in the range of 13% to 17% by weight. It should be understood that these ranges are provided to assist the reader in envisioning the working formulation of the inventors' compositions, and it should also be understood that formulations using any weight percentage within any of the ranges of Al 2 O 3 described herein can be used to achieve an acceptable formulation for the purposes presented by the present invention.

[0063] The glass fibers of the present invention typically also include compositions having more than 3% to 8% by weight of phosphorus pentoxide (P 2 O 5 , also referred to as phosphorus pentoxide). Alternatively, the phosphorus pentoxide content may be more than 3% to 7.5% by weight. Further alternatively, the phosphorus pentoxide content may be more than 3% to 7% by weight. The inventors have surprisingly found that this range is optimal for balancing Df behavior with T liq and the melt instability index. More specifically, it has been found that P 2 O 5 is synergistically related to the Al 2 O 3 content of the glass, reducing melt stability (increasing the instability index value), while at the same time improving important numerical indicators of Df and T liq . The inventors have found that phosphorus selectively associates with a portion of Al 2 O 3 to form an AlPO 4 network connection, forming an Al 2 O 3It is presumed that a part of it cannot devitrify into aluminoborate mullite. Although the inventors consider that it may adversely affect the viscosity in view of matters known to those skilled in the art, it is necessary to note that the weight percentage range of this more than 3% to 7% of P 2 O 5 has been specified.

[0064] Alkaline earth oxides (magnesium oxide (MgO), calcium oxide (CaO) and optionally strontium oxide (SrO)) all help these glasses to melt and homogenize at reasonable temperatures achievable by melting furnaces known in the art. However, these oxides directly affect and impair the low dielectric behavior desired in the industry (MgO does not increase Df more than CaO, and SrO increases Df more than CaO). CaO is generally a preferred alkaline earth additive because it gives the best compromise of viscosity, T liq and Df. Also, if the alkaline earth oxide is excessively low, the glass melt becomes unstable (the index increases). For at least this reason, the glass fiber composition of the present invention may also contain CaO (also referred to as calcia herein) and / or MgO as follows.

[0065] In some embodiments of the present invention, the glass fiber of the present invention comprises a composition having calcium oxide in excess of 0.25 weight percent to 7.0 weight percent calcium oxide. Alternatively, the calcium oxide content may be greater than 0.25 weight percent to 6.5 weight percent. Further alternatively, the calcium oxide content may be greater than 0.25 weight percent to 6 weight percent. Still further alternatively, the calcium oxide content may be greater than 2.5 weight percent to 5.0 weight percent. The weight percent of calcium oxide can affect the viscosity and devitrification process of the glass fiber. A high percentage of calcium oxide above 7.0 weight percent can cause insufficient dielectric properties. Further, a low percentage of calcium oxide below 0.25 weight percent can cause poor fiber formation. For example, with less than 0.25 weight percent calcia, the viscosity is too high and the resulting glass homogeneity is insufficient for acceptable continuous fiber formation. When combined with other components defined herein, in some embodiments, a calcium oxide content of 1.25 weight percent to 5.85 weight percent typically results in glass fibers having not only a desirable low dielectric constant but also a low loss factor. In one embodiment of the glass fiber and / or glass composition of the present invention, the calcia content is 4.5 weight percent or less. Alternatively, the calcia content is 4.25 weight percent or less. Further alternatively, the calcia content is 4.00 weight percent or less.

[0066] The glass fiber composition of the present invention may also include MgO (also referred to as magnesia in this specification). The glass fibers of the present invention may include a composition having magnesium oxide of 5.0 weight percent or less. Alternatively, the magnesium oxide content may be 4.5 weight percent or less. Further alternatively, the magnesium oxide content may be 4.0 weight percent or less. In a further alternative embodiment, the magnesium oxide content may be 2.0 weight percent or less. In a further alternative embodiment, the magnesium oxide content may be 1.5 weight percent or less. Similar to calcium oxide, the weight percent of magnesium oxide can also have an adverse effect on the viscosity and devitrification process of the glass fiber. Furthermore, a high percentage of magnesium oxide exceeding 5.0 weight percent may cause insufficient dielectric properties.

[0067] Titanium oxide (TiO 2 ) is optionally present in or intentionally introduced into the glass composition and fibers of the present invention. In one embodiment, the weight percent of titanium oxide is 6.0 or less. Alternatively, the weight percent of titanium oxide is 5.5 or less. Further alternatively, the weight percent of titanium oxide is 5.0 or less. When titanium oxide is 6 weight percent or more, particularly when combined with phosphorus pentoxide, the tendency of phase separation in the glass composition and fibers seems to increase. Titanium oxide typically acts as a viscosity reducer and may be intentionally added or present as an impurity from conventional raw materials. For this reason, titanium oxide can be present in the glass composition at a weight percent of 0.01 or more. Alternatively, titanium oxide may be present in the glass composition at a weight percent of 0.05 or more. Further alternatively, titanium oxide may be present in the glass composition at a weight percent of 0.1 or more.

[0068] The presented objective of the present invention is to produce the most stable glass reasonably possible for the melting and spinning processes, so in this family, TiO containing 6 weight percent or less 2 is T liqIt would not have been expected by those skilled in the art that it could be tolerated without adversely affecting these glasses and without causing a delta T behavior (delta T < 40 °C) that would render them non-spinnable. See page 37 of Wolfram Holand, et al., Glass Ceramic Technology, 2nd Edition, Wiley and Sons, July 2012.

[0069] TiO 2 is known in the art as an additive acceptable for other low D glasses to reduce viscosity. In view of this, it was contrary to common sense that the inventors were able to achieve an acceptable delta T range (T log3 - T k ) in the parent glass composition by incorporating any amount of a nucleating agent (TiO 2 , which is expected to increase the crystallization rate and possibly T liq but is also known to reduce the viscosity (T log3)). liq )

[0070] Interestingly, none of the related prior art discloses any example of combining P 2 O 5 with a significant amount of TiO 2 , and it is difficult to predict any synergistic or desirable behavior.

[0071] Additional oxides may be present in the glass fibers and compositions of the present invention without departing from the scope of the present invention. For example, lithium oxide (Li 2 O), sodium oxide (Na 2 O), potassium oxide (K 2 O), barium oxide (BaO), strontium oxide (SrO), zinc oxide (ZnO), fluorine (F or F 2 ), tin oxide (SnO 2 ), zirconium oxide (ZrO 2 ), chromium oxide (Cr 2 O 3 ), iron oxide (Fe 2 O 3 ), lanthanum oxide (La2 O 3 )), manganese oxide (Mn 2 O 3 ), yttrium oxide (Y 2 O 3 ), and / or vanadium oxide (V 2 O 3 )), etc., may be present. Further, the total of these additional oxides is 3 weight percent or less of the total composition, as long as the function of the glass is not changed. Alternatively, the total of these additional oxides may be 2 weight percent or less of the total composition. Further alternatively, the total of these additional oxides may be 1.5 weight percent or less of the total composition. Further alternatively, the total of these additional oxides may be 3.0 weight percent, 2.0 weight percent, and / or 1.0 weight percent or less of the total composition in some embodiments of the present invention.

[0072] Since even trace amounts of alkali metal oxides can have a significant impact on the glass composition, the total of alkali metal oxides such as Na 2 O, K 2 O, and Li 2 O is preferably 1.0 weight percent or less of the total composition. More preferably, the total is 0.5 weight percent or less of the total composition. Even more preferably, the total is 0.25 weight percent or less of the total composition.

[0073] Examples of the glass composition and glass fiber of the present invention are described herein. In one embodiment, the glass composition and / or glass fiber is 48.0 weight percent to 57.0 weight percent of SiO 2 , 15.0 weight percent to 26.0 weight percent of B 2 O 3 , 12.0 weight percent to 18.0 weight percent of Al 2 O 3 , more than 3.0 weight percent to 8.0 weight percent of P 2 O 5 , more than 0.25 weight percent to 7.0 weight percent of CaO, 5.0 weight percent or less of MgO, and 6.0 weight percent or less of TiO2 It includes. The alternative glass composition and / or glass fiber of the present invention contains 49 wt% to 56.5 wt% of SiO 2 , 15.5 wt% to 25.5 wt% of B 2 O 3 , 12.5 wt% to 17.5 wt% of Al 2 O 3 , more than 3.0 wt% to 7.5 wt% of P 2 O 5 , more than 0.25 wt% to 6.5 wt% of CaO, 4.50 wt% or less of MgO and 5.5 wt% or less of TiO 2 . The further alternative glass composition and / or glass fiber of the present invention may include the following components: 50 wt% to 56.0 wt% of SiO 2 , 16.0 wt% to 25.0 wt% of B 2 O 3 , 13.0 wt% to 17.0 wt% of Al 2 O 3 , more than 3.0 wt% to 7.0 wt% of P 2 O 5 , more than 0.25 wt% to 6.0 wt% of CaO, 4.0 wt% or less of MgO and 5.0 wt% or less of TiO 2 .

[0074] The glass composition of the present invention has a liquidus temperature above 1100 °C. In an alternative embodiment, the glass composition may have a liquidus temperature above 1150 °C. In a further alternative embodiment, the glass composition may have a liquidus temperature above 1200 °C. Setting the liquidus temperature above 1100 °C or more preferably above 1150 °C is advantageous for the spinning of the glass composition according to the present invention.

[0075] Furthermore, the glass composition of the present invention may have a T log3 viscosity temperature above 1350 °C. Alternatively, the glass composition may have a T log3 viscosity temperature above 1355 °C. In a further alternative embodiment, the glass composition may have a T log3 viscosity temperature above 1360 °C. Having a T log3 viscosity temperature above 1350 °C is advantageous for spinning the glass composition according to the present invention.

[0076] The glass fiber of the present invention may have a dielectric constant of 6 or less. Alternatively, the glass fiber may have a dielectric constant of 4.60 or less. In a further alternative embodiment, the glass fiber may have a dielectric constant of 4.55 or less.

[0077] Furthermore, the glass fiber of the present invention may have a loss coefficient of 38×10 -4 or less at a frequency of 10 GHz at room temperature. Alternatively, the glass fiber may have a loss coefficient of 30×10 -4 or less at a frequency of 10 GHz at room temperature. In a further alternative embodiment, the glass fiber of the present invention may have a loss coefficient of 25×10 -4 or less at a frequency of 10 GHz at room temperature.

[0078] The glass fiber of the present invention can be incorporated into glass fiber-reinforced articles such as printed circuit boards. Furthermore, the glass fiber of the present invention can be used in relation to products such as woven fabrics, non-woven fabrics, unidirectional fabrics, chopped strands, chopped strand mats, composite materials, and communication signal transmission media.

[0079] The present invention also includes a method for providing continuously manufacturable low-dielectric glass fibers. The method may include supplying a glass composition as disclosed herein to a melting zone of a glass melting furnace, heating the composition to a forming temperature above the liquidus temperature, and continuously spinning the molten glass to produce glass fibers with a low dielectric constant and a low loss coefficient.

[0080] As discussed above, the glass composition for providing low dielectric constant glass fibers is, at least in part, based on the weight percentages of the oxides discussed above, as well as the ratios and total weights of silicon dioxide, aluminum oxide, boron oxide, calcium oxide, magnesium oxide, phosphorus oxide and / or titanium oxide. In one aspect, in addition to other parameters discussed herein such as the T log3 viscosity temperature, a combination of these parameters makes it possible to obtain glass fibers having the low dielectric constant and low loss factor defined herein.

[0081] Compared with previous attempts in this field, the Creux formulation exemplifies a glass having completely inferior Df behavior (Df of about 0.0090 at 10 GHz) as shown in two examples of Patent Document 2. In contrast, the present invention achieves Df < 0.0028. Furthermore, the T log3 of Creux is less than 1350 °C and the T liq is less than 1000 °C.

[0082] On the other hand, Zhang does not describe the Df behavior of his glass at all. The T log3 of Zhang's glass is less than 1350 °C and all of the T liq are less than 1000 °C. Interestingly, Zhang states that his glass has excellent devitrification behavior because the primary crystals (wollastonite / diopside / anorthite) all compete with each other. See paragraph

[0014] of Patent Document 8.

[0083] Since the current state-of-the-art glass families have a T liq below 1000 °C and a T log3 viscosity temperature below 1350 °C, it is clear that it was not necessary to combine most, if not all, of the above prior arts to achieve the glass invention described herein.

[0084] It is known in the art that the chemical composition mainly determines the primary crystals that devitrify from the glass melt. See page 4 of Holland.

[0085] TiO2 It is known in the art that it is used by glass manufacturers as a nucleating agent that promotes the crystallization of glass and helps devitrify. See page 37 of Holland. However, none of the prior arts including Patent Document 1 of Mori, Patent Document 3 of Tamura, Patent Document 4 of Tamura, and Patent Document 6 of Yoshida are believed to produce a synergistic effect when combined in the amounts described herein by the inventors, a significant and / or substantial amount of P 2 O 5 along with TiO 2 has been proven or demonstrated to be effectively used.

[0086] Furthermore, the inventors unexpectedly discovered that the measured dielectric loss of the present invention seems to be closely related to the crystallization behavior of this glass. That is, glasses with higher T liq values tend to have better, i.e., lower Df characteristics. Figure 1 shows the relationship of this data obtained from the glass of the present invention.

[0087] To achieve the desired Df behavior (Df < 0.0028 or < 0.0027 or < 0.0026, or even lower), the glass defined by the formulation disclosed herein by the inventors tends to devitrify more easily, i.e., at higher T liq values, for example, values exceeding 1100 °C. Furthermore, the most desirable Df is at a T liq significantly higher than 1100 °C.

[0088] The inventors further surprisingly discovered that the most desirable glass for obtaining low Df behavior crystallizes into and forms aluminoborate mullite (acicular) crystals and has a unique network structure that is easy to form.

[0089] On the other hand, Zhang states explicitly that the glass produces wollastonite, diopside, and Ca feldspar crystals and does not produce aluminoborate mullite.

[0090] The inventors presume that the glass that tends to be included in the primary crystallization region of this aluminoborate mullite has an essentially suitable network structure for both good glass formation and excellent (i.e., low) Df behavior.

[0091] Similar to Creux, the glass invented by Kuhn (Patent Document 5) also has poor Df behavior (Df ≧ 0.0044), and only Example 1 among the six examples shows a positive delta T for acceptable fiber formation (see Table II of Kuhn).

[0092] Although unexpectedly effective formulations are generally described herein with the inventors' discoveries, further understanding can be obtained by referring to certain specific exemplary embodiments illustrated below. The embodiments are presented for illustrative purposes only and are not intended to be inclusive or limiting in any way other than as specified.

Examples

[0093] Examples of glass compositions prepared according to the present invention are described below. The specific components and their amounts, as well as other conditions and details listed in these examples, should not be construed as unduly limiting the present invention. In these examples, and throughout this specification, all percentages, ratios, and proportions are by weight (mass) unless otherwise indicated.

[0094] Exemplary glass compositions of the present invention are shown in Tables 1 to 12 below. The liquidus temperature of the glass compositions of the examples is represented as "T liq」 ", and the temperature at which the glass composition had a viscosity of 1000 poises is represented as "T 3 " (also referred to as the "T log3" viscosity temperature). The liquidus temperature and T 3 temperature of the glass compositions of the examples were measured for some glass compositions and calculated for others. Glass fibers were formed using the compositions of the examples, and the dielectric constant and loss factor were measured for some glass fibers and calculated for others. The dielectric constant is represented as the "Dk" value, and the loss factor is represented as the "Df" value.

[0095]

Table 1

[0096]

Table 2

[0097]

Table 3

[0098]

Table 4

[0099]

Table 5

[0100]

Table 6

[0101]

Table 7

[0102]

Table 8

[0103]

Table 9

[0104]

Table 10

[0105]

Table 11

[0106]

Table 12

[0107] Batches having the sample glass compositions shown in Tables 1 to 12 were prepared as follows. Glass synthesis included batch pretreatment (mechanical and thermal), first melting, frittering or grinding in water, second melting, and finally injection of the glass into a graphite mold.

[0108] In accordance with ASTM C 829-81, glass samples were tested for crystallization ability (liquidus temperature).

[0109] T log3 viscosity temperature was measured using ASTM C 965-81.

[0110] Measurement of dielectric properties at 10 GHz was performed using the Split Post Dielectric Resonator method, also known as the SPDR test in the art.

[0111] As shown in Tables 1 to 12, at 10 GHz, the glass compositions of the examples have a dielectric constant of less than 4.56 and a loss coefficient of 25×10 -4 as follows. Specifically, at 10 GHz, the dielectric constant is 4.22 to 4.56 and the loss coefficient is 18×10 -4 ~25×10 -4 That is. Therefore, the glass compositions of the examples exhibited a low dielectric constant and a low loss coefficient lower than those of E glass.

[0112] Furthermore, the glass composition of the example showed a T log3 viscosity temperature of 1374°C to 1447°C, similar to the typical T log3 viscosity temperature of D glass (about 1400°C). Having a T log3 viscosity temperature above 1350°C is advantageous for the spinning of the glass composition according to the present invention. For this reason, the glass composition according to the example and the embodiments of the present invention exceeds 1350°C.

[0113] Furthermore, the glass composition of the example showed a liquid phase temperature of 1136°C to 1374°C. Having a liquid phase temperature above 1100°C, or in some embodiments above 1150°C, is sufficient for the spinning of the glass composition according to the present invention. For this reason, the glass composition according to the example and the embodiments of the present invention exceeds 1100°C.

Industrial Applicability

[0114] The glass fiber of the present invention has a low dielectric constant and a low loss factor and is excellent as a glass fiber for printed wiring boards. This glass fiber is particularly suitable for strengthening printed wiring boards for high-density circuits used in high-speed routing systems. Furthermore, the glass composition used in the production of the fibers of the present invention has excellent processability. Therefore, stable low-dielectric glass fibers can be easily produced.

[0115] Various substrates including, but not limited to, woven fabrics, non-woven fabrics, unidirectional fabrics, knitted products, chopped strands, rovings, filament wound products, glass powders, and mats can be produced using the glass fiber of the present invention. Composite materials formed from at least one of these substrates and a plastic resin matrix (such as thermosetting plastics, composite thermoplastics, sheet molding compounds, bulk molding compounds, or prepregs, etc.) can also be used for strengthening peripheral communication devices and the like. For example, the composite material containing the glass fiber according to the present invention can be used for radar transmission applications at frequencies in the range of about 300 MHz to about 30 GHz.

[0116] The disclosed and described methods relate to glass fibers. The glass fibers can be obtained by mechanically attenuating the flow of molten glass flowing out of an opening located at the base of a spinning bushing powered by resistance heating or other means. These glass fibers can be particularly targeted for the manufacture of meshes and fabrics used in composite materials having organic and / or inorganic matrices.

[0117] If desired, detailed embodiments of the present invention are disclosed herein. However, it should be understood that the disclosed embodiments are merely examples of the invention, which may be embodied in various alternative forms. Accordingly, the specific structural and functional details disclosed herein should not be construed as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art how to use the invention in various ways. It will be apparent to those skilled in the art that many changes and substitutions can be made to the above description of the preferred embodiments and examples without departing from the spirit and scope of the invention as defined by the appended claims.

[0118] Although various embodiments and examples of the present invention have been described above, these descriptions are presented for purposes of illustration and explanation. Variations, changes, modifications, and departures from the disclosed embodiments, systems, and methods can be adopted without departing from the spirit and scope of the present invention.

Claims

1. A glass composition comprising: 48.0 weight percent to 57.0 weight percent of SiO ２ and 15.0 weight percent to 26.0 weight percent of B ２ O ３ and 12.0 wt% to 18.0 wt% of Al ２ O ３ and P of more than 3.0 weight percent to 8.0 weight percent ２ O ５ and More than 0.25 wt% to 7.0 wt% of CaO; 5.0 wt% or less of MgO; 0.57 wt% to 6.0 wt% of TiO ２ and And having a glass viscosity of 1000 poises at a temperature above 1350 °C and a liquidus temperature above 1100 °C.

2. 49.0 wt% to 56.5 wt% of SiO ２ and 15.5 wt% to 25.5 wt% of B ２ O ３ and 12.5 wt% to 17.50 wt% of Al ２ O ３ and P of more than 3.0 weight percent to 7.5 weight percent ２ O ５ and More than 0.25 wt% to 6.5 wt% of CaO; 4.5 wt% or less of MgO; 0.57 wt% to 5.5 wt% of TiO ２ and The glass composition according to claim 1, further comprising.

3. 50.0 weight percent to 56.0 weight percent of SiO ２ and 16.0 wt% to 25.0 wt% of B ２ O ３ and 13.0 wt% to 17.0 wt% of Al ２ O ３ and P of more than 3.0 weight percent to 7.0 weight percent ２ O ５ and More than 0.25 wt% to 6.0 wt% of CaO; 4.0 wt% or less of MgO; 0.57 to 5.0 weight percent of TiO ２ and The glass composition according to claim 1, further comprising.

4. SiO of 49.0 wt% or more ２ , SiO at 56.5 weight percent or less ２ , 15.5 weight percent or more of B ２ O ３ , B at 25.5 weight percent or less ２ O ３ , Al of 17.50 wt% or less ２ O ３ , P of 7.0 weight percent or less ２ O ５ , CaO of 6.5 wt% or less; 4.5 wt% or less of MgO, and / or; 0.57 wt% to 5.5 wt% of TiO ２ , The glass composition according to claim 1, further comprising one or more of.

5. 50.0 weight percent or more of SiO ２ , SiO at 56.0 wt% or less ２ , 16.0 weight percent or more of B ２ O ３ , B of 25.0 weight percent or less ２ O ３ , Al of 17.0 weight percent or less ２ O ３ , P of 7.0 weight percent or less ２ O ５ , CaO of 6.0 wt% or less; 4.0 wt% or less of MgO, and / or; 0.57 wt% to 5.0 wt% of TiO ２ , The glass composition according to claim 1, further comprising one or more of.

6. The glass composition according to claim 1, which crystallizes into aluminoborate mullite crystals and has a unique network structure that facilitates its formation.

7. A method for providing continuously manufacturable low-dielectric glass fibers, comprising: supplying the glass composition according to claim 1 to a melting zone of a glass melting furnace; Heating the composition to a forming temperature above the liquidus temperature to obtain molten glass; Continuously spinning the molten glass to produce glass fibers with a low dielectric constant and a low loss factor.

8. More than 0.25 wt% to 7.00 wt% of CaO; 48.0 wt% to 57.0 wt% of SiO ２ and 15.0 wt% to 26.0 wt% of B ２ O ３ and 12.0 wt% to 18.0 wt% of Al ２ O ３ and P of more than 3.0 weight percent to 8.0 weight percent ２ O ５ and 5.0 wt% or less of MgO; Low-dielectric glass fibers formed from a glass composition having a glass viscosity of 1000 poises at a temperature above 1350 °C and a liquidus temperature above 1100 °C. 0.57 to 6.0 weight percent of TiO ２ and

9. Wherein the glass composition; More than 0.25 wt% to 6.5 wt% of CaO; 49.0 wt% to 56.5 wt% of SiO ２ and 15.5 wt% to 25.5 wt% of B ２ O ３ and 12.5 wt% to 17.50 wt% of Al ２ O ３ and P of more than 3.0 wt% to 7.5 wt% ２ O ５ and 4.5 wt% or less of MgO; The low-dielectric glass fibers according to claim 8, further comprising. 0.57 to 5.5 weight percent of TiO ２ and

10. Wherein the glass composition; More than 0.25 wt% to 6.0 wt% of CaO; 50.0 weight percent to 56.0 weight percent of SiO ２ and 16.0 wt% to 25.0 wt% of B ２ O ３ and 13.0 wt% to 17.0 wt% of Al ２ O ３ and P of more than 3.0% by weight to 7.0% by weight ２ O ５ and 4.0 wt% or less of MgO; The low-dielectric glass fibers according to claim 8, further comprising. 0.57 wt% to 5.0 wt% of TiO ２ and

11. Wherein the glass composition; CaO of 6.5 wt% or less; SiO of 49.0 wt% or more ２ , SiO of 56.5 wt% or less ２ , B of 15.5 weight percent or more ２ O ３ , B of 25.5 weight percent or less ２ O ３ , Al of 17.50 wt% or less ２ O ３ , P of 7.0 wt% or less ２ O ５ , 4.5 wt% or less of MgO, and / or; ​ 0.57 weight percent to 5.5 weight percent of TiO ２ , The low-dielectric glass fiber according to claim 8, further comprising one or more of

12. wherein the glass composition 50.0 weight percent or more of SiO ２ , SiO at 56.0 wt% or less ２ , 16.0 weight percent or more of B ２ O ３ , B at 25.0 weight percent or less ２ O ３ , Al of 17.0 wt% or less ２ O ３ , P of 7.0 weight percent or less ２ O ５ , CaO of 6.0 wt% or less, MgO of 4.0 wt% or less, and / or 0.57 weight percent to 5.0 weight percent of TiO ２ , The low-dielectric glass fiber according to claim 8, further comprising one or more of

13. The glass fiber according to claim 8, having a dielectric constant of 6 or less and / or a loss factor of 38×10 －４ or less at a frequency of 10 GHz at room temperature.

14. The glass fiber according to claim 8, having a dielectric constant of 4.60 or less and / or a loss coefficient of 30×10 －４ or less at a frequency of 10 GHz at room temperature.

15. At room temperature, having a dielectric constant of 4.55 or less and / or a loss factor of 25×10 －４ or less at a frequency of 10 GHz, the glass fiber according to claim 8.

16. A glass fiber-reinforced article comprising the glass fiber according to claim 8.

17. The glass fiber-reinforced article according to claim 16, which is a printed circuit board.

18. The glass fiber according to claim 8, formed from a glass composition that crystallizes into aluminoborate mullite crystals and has a unique network structure that facilitates its formation.

19. A product comprising the glass fiber according to claim 8, selected from the group consisting of printed circuit boards, woven fabrics, non-woven fabrics, unidirectional fabrics, chopped strands, chopped strand mats, composite materials, and communication signal transmission media.

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