JP2023509138A - Low dielectric glass compositions, fibers and articles - Google Patents

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 comprise 48.0 weight percent to 58.0 weight percent SiO2, 15.0 weight percent to 26.0 weight percent B2O3, 12.0 weight percent to 18.0 weight percent Al2O3, greater than 0.25 weight percent to 3.0 weight percent P2O5, greater than 0.25 weight percent to 7.00 weight percent CaO, up to 5.0 weight percent MgO, greater than 0 weight percent to 1.5 weight percent percent SnO2 and up to 6.0 weight percent TiO2. Further, the glass composition has a glass viscosity of 1000 poise at temperatures above 1350°C and has a liquidus temperature above 1000°C.

Description

[Related Application]
This application is subject to PCT Section 8 of U.S. Application No. 16/732,825 filed January 2, 2020 and U.S. Application No. 16/792,658 filed February 17, 2020. claiming the benefit of priority under These applications are International Application No. PCT/US17/67785 filed December 21, 2017 claiming priority from U.S. Patent Application No. 62/439,755 filed December 28, 2016 No. 16/474,287, filed Jun. 27, 2019 as a National Stage application of . The contents of the above application are hereby incorporated by reference as if fully set forth herein.

The present invention relates to glass compositions and fibers. More particularly, the present invention relates to glass compositions and fibers having low dielectric constants and low loss factors. Additionally, the glass fibers of the present invention are preferably suitable for use in connection with electronic related devices such as reinforcement of printed circuit laminates and the like.

Modern electronic devices generally comprise printed circuit boards that are reinforced with fiberglass. Many modern electronic devices such as mobile or landline wireless phones, computers, smart phones, tablets, etc. have electronic systems that operate at high processing speeds and high or very high frequencies. When the glass is exposed to such high or very 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 "permittivity" and "dielectric loss tangent" of the glass composition as shown by the following equations:
W=k・f・v ²・ε・(tan δ)

In the above equation, "W" is the dielectric loss energy in the glass, "k" is a constant, "f" is the frequency, " ^v2 " is the potential slope, and "ε" is the dielectric constant. and “tan δ” is the dielectric loss tangent. The dissipation factor (tan δ) is dimensionless and is often referred to in the art by the following synonyms: "loss factor" or more commonly "loss factor" (Df). As the above equation indicates, the dielectric loss energy "W" increases with increasing dielectric constant and dielectric loss tangent (loss factor, Df) of the glass and/or increasing frequency.

Two types of glass fibers commonly used in reinforcing 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, E-glass is a poor reinforcement material for printed circuit boards with higher density electronic components and higher processing speeds because E-glass can result in relatively high dielectric losses. D-glass, on the other hand, has a relatively low dielectric constant and loss factor. However, D-glass has a relatively high melting temperature, relatively low processability, relatively low mechanical performance and relatively low water resistance. In addition, D-glass can have poor adhesion with epoxy resins and generally has defects in the form of striae and bubbles. Therefore, neither E-glass nor D-glass are ideally suited for use as reinforcing fibers in high-speed printed circuit boards, and neither is well suited for circuit boards operating at high or very high frequencies from about 100 MHz to about 18 GHz. do not have.

Prior attempts to provide glass formulations suitable for electronics include Mori, US Pat. No. 6, Sawanoi US Pat. No. 7, and Zhang US Pat.

U.S. Pat. No. 5,958,808 U.S. Patent Application Publication No. 2004/01755557 U.S. Pat. No. 6,309,990 U.S. Pat. No. 6,846,761 WO2010/011701 U.S. Patent Application Publication No. 2011/0281484 U.S. Pat. No. 8,679,993 Chinese Patent Application Publication No. 103351102

In one aspect of the invention, the glass composition comprises from 48.0 weight percent to 58.0 weight percent SiO ₂ and from 15.0 weight percent B ₂ O ₃ to 26.0 weight percent B _{2 O3} , comprising 12.0 weight percent Al ₂ O ₃ to 18.0 weight percent Al ₂ O ₃ , and more than 0.25 weight percent to 3.0 weight percent P ₂ O ₅ , 6. more than 0.25 weight percent to 7.0 weight percent CaO, less than or equal to 5.0 weight percent MgO, consisting essentially of more than 0 weight percent to 1.5 weight percent SnO ₂ ; A glass composition is provided comprising no more than 0 weight percent TiO ₂ , having a glass viscosity of 1000 poise at a temperature of greater than 1350° C., and having a liquidus temperature of greater than 1000° C., wherein "substantially from Consists, as used elsewhere herein, applies only to the _SnO2 component of the formulation.

In one embodiment of the invention, the glass composition further comprises 49.0 weight percent to 57.5 weight percent SiO ₂ and 15.5 weight percent to 25.5 weight percent B ₂ O ₃ . further comprising from 12.5 weight percent to 17.50 weight percent Al ₂ O ₃ , further comprising from greater than 0.25 weight percent to 3.0 weight percent P ₂ O ₅ , greater than 0.25 weight percent further comprising ~6.5 weight percent CaO, further comprising no more than 4.5 weight percent MgO, consisting essentially of greater than 0 weight percent to 1.25 weight percent _SnO2 , and no more than 5.5 weight percent of _TiO2 .

In one embodiment of the invention, the glass composition further comprises 50.0 weight percent to 57.0 weight percent SiO ₂ and 16.0 weight percent to 25.0 weight percent B ₂ O ₃ . further comprising from 13.0 weight percent to 17.0 weight percent Al ₂ O ₃ , further comprising from greater than 0.25 weight percent to 3.0 weight percent P ₂ O ₅ , greater than 0.25 weight percent further comprising ~6.0 weight percent CaO, further comprising no more than 4.0 weight percent MgO, consisting essentially of greater than 0 to 1.0 weight percent _SnO2 , and no more than 5.0 weight percent of _TiO2 .

In one embodiment of the invention, the composition comprises 49.0 weight percent or more _SiO2 , 57.5 weight percent or less _SiO2 , 15.5 weight percent or more _B2O3 , _25.5 weight percent 12.5 weight percent or more _Al2O3 , 17.50 weight percent or less _{Al2O3 , 0.25} weight percent _or more _P2O5 , _3.0 weight percent or _{less > 0.25} weight percent CaO, <6.5 weight percent CaO, <4.5 weight percent MgO, >0 weight percent _SnO2 , <1.25 weight percent _SnO2 , and/or up to 5.5 weight percent TiO ₂ .

In one embodiment of the invention, the composition comprises 50.0 weight percent or more _SiO2 , 57.0 weight percent or less _SiO2 , 16.0 weight percent or more _B2O3 , _25.0 weight percent _13.0 weight percent or more _Al2O3 , 17.0 weight percent or less _{Al2O3 ,} 0.25 weight percent _or more _P2O5 , _3.0 weight percent _or less > _0.25 weight percent CaO, <6.0 weight percent CaO, _< 4.0 weight percent MgO, >0 weight percent _SnO2 , <1.0 weight percent _SnO2 , and/or up to 5.0 weight percent TiO ₂ .

In one embodiment of the invention, the composition has a liquidus temperature above 1000°C.

In one embodiment of the invention, the composition has a liquidus temperature above 1050°C.

In one embodiment of the invention, the composition has a liquidus temperature above 1100°C.

In one embodiment of the invention, the composition has a glass viscosity of 1000 poise at temperatures above 1355°C.

In one embodiment of the invention, the composition has a glass viscosity of 1000 poise at temperatures above 1360°C.

In one embodiment of the invention, glass fibers are formed from the glass composition described above.

In one embodiment of the 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.

In one embodiment of the invention, the glass fiber has a dielectric constant of 4.80 or less and/or a loss factor of 30×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature.

In one embodiment of the invention, the glass fiber has a dielectric constant of 4.70 or less and/or a loss factor of 28×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature.

In one embodiment of the present invention, the glass composition has a unique network structure that facilitates the formation of and crystallizes into aluminoborate mullite crystals as the primary devitrification phase.

In one embodiment of the invention, the steps of feeding any of the glass compositions described herein into a melting zone of a glass melting furnace and heating the composition to a forming temperature above the liquidus temperature. and continuously spinning said molten glass to produce low dielectric constant and low loss factor glass fibers.

In one aspect of the invention, 48.0 weight percent to 58.0 weight percent SiO ₂ , 15.0 weight percent to 26.0 weight percent B ₂ O ₃ , 12.0 weight percent to 18.0 weight percent Al ₂ O ₃ , more than 0.25 weight percent to 3.0 weight percent P ₂ O ₅ , more than 0.25 weight percent to 7.00 weight percent CaO, 5.0 _{wt .} Further provided are low dielectric glass fibers formed from a glass composition having a glass viscosity of Poise and having a liquidus temperature greater than 1000°C.

In one embodiment of the invention, the glass composition further comprises 49.0 weight percent to 57.5 weight percent SiO ₂ and 15.5 weight percent to 25.5 weight percent B ₂ O ₃ . further comprising from 12.5 weight percent to 17.50 weight percent Al ₂ O ₃ , further comprising from greater than 0.25 weight percent to 3.0 weight percent P ₂ O ₅ , greater than 0.25 weight percent further comprising ~6.5 weight percent CaO, further comprising no more than 4.5 weight percent MgO, consisting essentially of greater than 0 weight percent to 1.25 weight percent _SnO2 , and no more than 5.5 weight percent of _TiO2 .

In one embodiment of the invention, the glass composition further comprises 50.0 weight percent to 57.0 weight percent SiO ₂ and 16.0 weight percent to 25.0 weight percent B ₂ O ₃ . further comprising from 13.0 weight percent to 17.0 weight percent Al ₂ O ₃ , further comprising from greater than 0.25 weight percent to 3.0 weight percent P ₂ O ₅ , greater than 0.25 weight percent further comprising ~6.0 weight percent CaO, further comprising no more than 4.0 weight percent MgO, consisting essentially of greater than 0 to 1.0 weight percent _SnO2 , and no more than 5.0 weight percent of _TiO2 .

In one embodiment of the invention, the composition comprises 49.0 weight percent or more _SiO2 , 57.5 weight percent or less _SiO2 , 15.5 weight percent or more _B2O3 , _25.5 weight percent 12.5 weight percent or more _Al2O3 , 17.50 weight percent or less _{Al2O3 , 0.25} weight percent _or more _P2O5 , _3.0 weight percent or _{less > 0.25} weight percent CaO, <6.5 weight percent CaO, <4.5 weight percent MgO, >0 weight percent _SnO2 , <1.25 weight percent _SnO2 , and/or up to 5.5 weight percent TiO ₂ .

In one embodiment of the invention, the composition comprises 50.0 weight percent or more _SiO2 , 57.0 weight percent or less _SiO2 , 16.0 weight percent or more _B2O3 , _25.0 weight percent _13.0 weight percent or more _Al2O3 , 17.0 weight percent or less _{Al2O3 ,} 0.25 weight percent _or more _P2O5 , _3.0 weight percent _or less _{> 0.25} weight percent CaO; <6.0 weight percent CaO; <4.0 weight percent MgO; >0 weight percent _SnO2 ; <1.25 weight percent _SnO2 , and/or up to 5.0 weight percent TiO ₂ .

In one embodiment of the invention, the glass composition has a liquidus temperature above 1000°C.

In one embodiment of the invention, the glass composition has a liquidus temperature above 1050°C.

In one embodiment of the invention, the glass composition has a liquidus temperature above 1100°C.

In one embodiment of the invention, the glass composition has a glass viscosity of 1000 poise at temperatures above 1355°C.

In one embodiment of the invention, the glass composition has a glass viscosity of 1000 poise at temperatures above 1360°C.

In one embodiment of the 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.

In one embodiment of the invention, the glass fiber has a dielectric constant of 4.80 or less and/or a loss factor of 30×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature.

In one embodiment of the invention, the glass fiber has a dielectric constant of 4.70 or less and/or a loss factor of 28×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature.

In one embodiment of the invention, the glass fibers are formed from a glass composition that has an inherent network structure that favors the formation of aluminoborate mullite crystals that crystallize as the first devitrified phase.

The present invention also includes glass fiber reinforced articles, such as printed circuit boards, incorporating the glass fibers of the present invention. Further, the present invention includes products incorporating glass fibers as disclosed above, which products include printed circuit boards, woven fabrics, nonwoven fabrics, unidirectional fabrics, chopped strands, chopped strand mats, composites and telecommunication signal transport. medium.

The present invention includes a method of providing continuous manufacturable low dielectric glass fibers. The method comprises the steps of feeding a glass composition as disclosed herein into 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 a low dielectric constant and low loss factor glass fiber.

The present invention relates to glass compositions and fibers that preferably have low dielectric constant values and low loss factors (also referred to herein as tan δ). The glass fibers of the present invention are preferably suitable for applications in connection with electronic devices and systems operating at high processing speeds and/or high frequencies, such as mobile or fixed wireless telephones, computers, smart phones, tablets and the like. The glass fibers of the present invention preferably produce a lower dielectric constant and loss factor than E-glass, but have better processing properties than D-glass. Although described primarily in terms of their use in connection with electronic devices and reinforcement of printed circuit boards, other uses and advantages of the glass compositions and glass fibers of the present invention depart from the spirit and scope of the present invention. can be contemplated without The present invention relates to glass fiber reinforced articles, products incorporating glass fibers such as printed circuit boards, woven fabrics, nonwoven fabrics, unidirectional fabrics, chopped strands, chopped strand mats, composites and communication signal carrying media, and continuously manufacturable media. A method of providing a low dielectric glass fiber is also disclosed.

The compositions of _the present invention generally comprise silicon oxide ( _SiO2 ), _boron oxide ( _B2O3 ), aluminum oxide ( _Al2O3 ), calcium oxide ( _CaO ), phosphorus oxide ( _P2O5 ), It is composed of one or more oxides including magnesium oxide (MgO), tin oxide ( _SnO2 ) and titanium oxide ( _TiO2 ). Additional oxides may be present as discussed below without departing from the spirit and scope of the invention. The compositions of the present invention, in some embodiments, have a liquidus temperature of greater than 1000°C and a glass viscosity of 1000 poise at a temperature (T log3) of greater than 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 glass preferably has the ability to be continuously spun due to its positive difference (ΔT ₃ ) between the T log3 viscosity temperature and the liquidus temperature.

Unless otherwise stated, the following terms used in the specification and claims have the meanings indicated below.

As used herein, the term “liquidus” generally includes the temperature (T _liq ) at which equilibrium exists between the liquid glass and its primary crystalline phase. Given its usual and customary meaning, at all temperatures above the liquidus the glass melt has no crystals in its primary region, and at temperatures below the liquidus the crystals are molten. It can be formed in liquid. The liquidus temperature thus provides a useful lower temperature limit above which continuous spinning of the glass is possible.

The terms "spinning temperature" or "T log3 viscosity temperature" are understood to mean the temperature at which the glass has a viscosity equal to 1000 poise (denoted by T log3).

As used herein, the term “delta T,” also referred to as “ΔT ₃ ,” has its usual and customary meaning in the art, which generally includes the difference between the spinning temperature and the liquidus. is given and thus the spinning properties of the glass composition. The higher the delta T, the more process flexibility there is in forming the glass fibers and the less likely devitrification (crystallization) of the glass melt will occur during melting and spinning. Generally, the higher the delta T, the lower the production cost of the glass fiber, in part by providing longer bushing life and a wider fiber forming process window.

The term "fiber" refers to an elongated body whose length dimension is greater than the transverse dimensions of width and thickness. Thus, the term fiber includes monofilaments, multifilaments, ribbons, strips, staples, and other forms of regular or irregular cross-section, chopped, chopped or discontinuous fibers, etc. is included. Fiber and filament are used interchangeably herein.

The term "E-glass" is used according to its meaning as set forth in ASTM D-578.

The term "D-Glass" refers to a glass composition having the properties defined herein.

By "low dielectric constant" is meant glass fibers having a dielectric constant lower than that of E-glass. As an example, E-glass has a dielectric constant of about 6.1 at room temperature and a frequency of 10 GHz.

By "low loss factor" is meant a glass fiber that has a lower loss factor than E-glass. As an example, E-glass has a loss factor of about 38×10 ⁻⁴ at a frequency of about 10 GHz at room temperature.

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

In general, a glass that has been melted at a sufficiently high temperature for a sufficiently long time tends to be chemically and structurally homogeneous, ie, devoid of regions of different chemical composition or atomic arrangement. Furthermore, the minimum homogeneity required for continuous spinning is a melt state that allows stable and continuous formation of fibers as the inhomogeneity is too small to interfere with the spinning process. Efficient spinning requires consistent glass melt quality with respect to liquid viscosity. Fluctuations in viscosity impede flow and cause fiber breakage during formation. Glass melt defects due to either unmelted batch material (stones), poorly melted or homogenized glass (striae/cords) and devitrification products (crystals formed at temperatures below _Tliq ) is a typical cause. In the course of our research, we have found that the glasses of this family of glasses are prone to liquid-liquid immiscibility (glass phase separation) on cooling from high temperatures. Phase separation is the tendency of a homogeneous liquid at high temperature to thermodynamically separate upon cooling into two different glasses, often with very different compositions, liquid structures and related properties. In addition, phase separated glasses can exhibit discontinuous rather than continuous viscosity behavior as a function of temperature, thus phase separated regions of the melt can interfere with stable fiber formation.

In an attempt to understand and control this phase separation tendency, the inventors have utilized the following method to characterize the stability of each composition of the glass melt after melting and during cooling. After each melting cycle, the crucible was removed from the furnace and allowed to cool naturally until it was below the glass transition temperature _Tg . The less stable glasses exhibited varying degrees of opalescence (light scattering) in the cooled state. Each melt was graded on a scale of 1-6 from no opalescence (1, very stable) to 6 (least stable, opaque) (“melt instability index”). These ratings were sufficient to help distinguish between regions of good glass-forming stability and regions of poor 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 the specification, including with respect to the test results table below.

A glass composition is provided for the formation of glass fibers that are preferably suitable for use in electronic applications and articles and can be economically formed into glass fibers, preferably by continuous spinning.

In some embodiments of the invention, the glass fiber comprises a composition having from 45 weight percent to 58 weight percent silicon dioxide (SiO ₂ ) (also referred to herein as silica). Alternatively, the silicon dioxide content may be from 45.5 weight percent to 57.5 weight percent. Still alternatively, the silicon dioxide content may be between 46 weight percent and 57 weight percent. In further embodiments, the silicon dioxide content may be less than 56.75 weight percent. In still further embodiments, the silicon dioxide content may be less than 56.50 weight percent. If the percentage of silicon dioxide is outside this range, the viscosity and spinning of the glass are typically affected. For example, if silicon dioxide is less than 45 weight percent of the total composition of the glass fiber, the viscosity of the glass can be reduced to the extent that devitrification (crystallization) occurs during spinning. In contrast, if silicon dioxide is greater than 58 weight percent of the total glass fiber composition, the glass may become too viscous and more difficult to melt, homogenize and refine. For this reason, the silica content is preferably between 45% and 58% by weight of the total composition of the glass. Furthermore, when combined with other components defined herein, a silica content of 45.00 weight percent to 58.00 weight percent typically provides glass fibers with a desirable low dielectric constant as well as a low loss factor. bring. In one embodiment of the glass fiber and/or glass composition of the present invention, the silica content is at least 45.50 weight percent. Alternatively, the silica content is at least 46.00 weight percent. In another embodiment of the glass fiber and/or glass composition of the present invention, the silica content is 57.50 weight percent or less. Alternatively, the silica content is 57.00 weight percent or less. Still alternatively, the silica content is 56.75 weight percent or less. In another embodiment, the silica content is 56.50 weight percent or less.

Notwithstanding the above, the inventors have discovered certain surprisingly useful and/or effective formulations comprising compositions in which the glass fibers have from 48 weight percent to 58 weight percent silicon dioxide (SiO ₂ ). identified. Alternatively, the silicon dioxide content may be from 49 weight percent to 57.5 weight percent. Further alternatively, the silicon dioxide content may be from 50 weight percent to 57 weight percent. In further embodiments, the silicon dioxide content may be less than 57.0 weight percent. If the silicon dioxide percentage is outside these ranges, the viscosity and spinning of the glass are typically affected. For example, if silicon dioxide is less than 48 weight percent of the total composition of the glass fiber, the viscosity of the glass can be reduced to the extent that devitrification (crystallization) occurs during spinning. In contrast, if silicon dioxide is greater than 58 weight percent of the total glass fiber composition, the glass may become too viscous and more difficult to melt, homogenize and refine. For this reason, the silica content is preferably between 48% and 58% by weight of the total composition of the glass. It is also understood that _SiO2 is useful in controlling the stability of the formulation, and the weight percent of _SiO2 is also arbitrarily selected for such considerations in combination with other factors described herein. There is a need to.

The glass fibers in some embodiments _of the present invention comprise compositions having more than 18 weight percent boron oxide ( _B2O3 ) and no more than 26 weight percent boron oxide. Alternatively, the boron oxide content may be from 18.5 weight percent to 25 weight percent. Further alternatively, the boron oxide content may be between 19 weight percent and 22 weight percent. A high percentage of boron oxide, such as greater than 26 weight percent, can cause excessive loss of _B2O3 upon melting, poor homogeneity, _low strength and poor mechanical properties. A glass with a boron oxide content greater than 18.00 weight percent and less than or equal to 26.00 weight percent typically has a desirable low dielectric constant as well as a low loss factor when combined with other components defined herein yields fibre. In one embodiment of the glass fiber and/or glass composition 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 fiber and/or glass composition of the present invention, the boron oxide content is 25.00 weight percent or less. Alternatively, the boron oxide content is 24.00 weight percent or less.

Notwithstanding the above, the inventors have _discovered certain surprisingly _useful and/or An effective formulation was identified. Although B ₂ O ₃ is beneficial in lowering 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 between 15.5 weight percent and 25.5 weight percent. Further alternatively, the boron oxide content may be between 16 weight percent and 25 weight percent. High percentages of boron oxide, such as above 26 weight percent, lead to excessive loss of _B2O3 during melting, poor homogeneity, poor mechanical properties, and instability of the glass in the form of _phase separation. may cause Additionally, low percentages of boron oxide, such as less than 15 weight percent, can cause poor dielectric properties. Therefore, the boron oxide content is preferably between 15% and 26% by weight of the total composition of the glass. Furthermore, when combined with other components defined herein, a glass with a boron oxide content of 15.00 weight percent to 26.00 weight percent typically has a desirable low dielectric constant as well as a low loss factor. yields fibre. 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. Further 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.

Glass fibers in some embodiments of the present invention comprise compositions having more than 16 weight percent and no more than 23 weight percent aluminum oxide. Alternatively, the aluminum oxide content may be greater than 16 weight percent and less than or equal to 22.5 weight percent. Still alternatively, the aluminum oxide content may be greater than 16 weight percent and less than or equal to 22 weight percent. The percentage of aluminum oxide relative to the total glass fiber composition can also affect the viscosity and spinning process. High percentages of aluminum oxide, such as, for example, greater than 23 weight percent, reduce melt viscosity and can lead to devitrification during spinning. Low percentages of aluminum oxide, such as 18 weight percent or less, can cause phase separation and poor fiber formation. For this reason, the alumina content is preferably greater than 16 weight percent and less than or equal 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 provides glass fibers with a desirable low dielectric constant as well as a low loss factor. bring. In one embodiment of the glass fiber and/or glass composition of the present invention, the alumina content is 22.50 weight percent or less. Alternatively, the alumina content is 22.00 weight percent or less.

Aluminum oxide is known to stabilize glasses that are prone to phase separation/melt instability. However, high levels are also known to increase the tendency to devitrify/crystallize and thus may adversely affect fiber formation stability with respect to delta T. Considering these tendencies of _{e.g. Al2O3} , which is in some respects diametrically opposed to _B2O3 , and other components of the formulations described, finding the right balance between all of _them . is important. In view of the above, notwithstanding the ranges previously disclosed herein, the inventors have found that in some embodiments of the present invention Al ₂ O ₃ is present in the range of 12 weight percent to 18 weight percent. Certain surprisingly useful and/or effective formulations have been identified in which a balance of Df and _Tliq behavior is achieved when In some embodiments of the invention, Al ₂ O ₃ is present in the range of 12.5 weight percent to 17.5 weight percent. In some embodiments of the invention, Al ₂ O ₃ is present in the range of 13 weight percent to 17 weight percent. It should be understood that these ranges are given to aid the reader in envisioning the working formulation of our compositions, and that any of the Al ₂ O ₃ described herein It should also be understood that formulations using any weight percent, including those within the range, can be used to achieve an acceptable formulation for the proposed purposes of the present invention.

The glass fibers of the present invention also typically include compositions having from greater than 0.25 weight percent to 3 weight percent phosphorus oxide (P ₂ O ₅ , also referred to as phosphorus pentoxide). The inventors have surprisingly found that this range is useful in balancing Df behavior with T _liq and melt instability index. More specifically, P ₂ O ₅ is synergistically related to the Al ₂ O ₃ content of the glass, decreasing the melt stability (increasing the instability index value), and at the same time significantly increasing Df and T _liq . Numerical indices were also found to improve. We found that phosphorus selectively associates with a portion of Al ₂ O ₃ and forms AlPO ₄ network linkages so that a portion of Al ₂ O ₃ cannot devitrify to aluminoborate mullite. We assume that This range of greater than 0.25 weight percent to 3 weight percent of P ₂ O ₅ is manufacturable low dielectric loss glass when combined with specified ranges of other compositional components as described herein. It should also be noted that the present inventors have confirmed that the effect on That is, in many of the compositions described herein, phosphorus is known to those skilled in the art to adversely affect some desirable properties of the resulting glass, such as increasing glass viscosity. deliberately chosen for use However, with careful balancing of the other elements in the composition and combined with our discovery of the surprising behavior of certain combinations of these elements, good glass compositions can be achieved.

Alkaline earth oxides (magnesium oxide (MgO) and/or calcium oxide (CaO)) help these glasses melt and homogenize at reasonable temperatures achievable by melting furnaces known in the art. . However, these oxides directly impact and compromise the low dielectric behavior desired by the industry (MgO does not increase Df more than CaO). CaO is generally the preferred alkaline earth additive as it offers the best compromise of viscosity, T _liq and Df compared to alternatives. Also, if the amount of alkaline earth oxides is too low, the glass melt becomes unstable (the index becomes high). For at least this reason, the glass fiber compositions of the present invention may also include CaO (also referred to herein as calcia) and/or MgO, as described below.

The glass fibers of the present invention, in some embodiments of the present invention, comprise compositions having from greater than 0.25 weight percent calcium oxide 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. Still alternatively, the calcium oxide content may be from greater than 0.25 weight percent to 6 weight percent. Still 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 glass fibers. High percentages of calcium oxide, such as greater than 7.0 weight percent, can cause poor dielectric properties. Additionally, low percentages of calcium oxide, such as 0.25 weight percent or less, can cause poor fiber formation. For example, below 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 1.0 weight percent to 6.0 weight percent is typically desirable, as well as a low dielectric constant, It results in glass fibers with 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. Still alternatively, the calcia content is 4.00 weight percent or less.

The glass fiber compositions of the present invention may also contain MgO (also referred to herein as magnesia). The glass fibers of the present invention may include compositions having no more than 5.0 weight percent magnesium oxide. Alternatively, the magnesium oxide content may be 4.5 weight percent or less. Still alternatively, the magnesium oxide content may be 4.0 weight percent or less. In further alternative embodiments, the magnesium oxide content may be 2.0 weight percent or less. In further alternative embodiments, the magnesium oxide content may be 1.5 weight percent or less. Similar to calcium oxide, the weight percentage of magnesium oxide also affects the viscosity and devitrification process of the glass fiber. Additionally, high percentages of magnesium oxide, such as greater than 5.0 weight percent, can cause poor dielectric properties.

The inventors have determined that in preferred embodiments of the present invention certain glass compositions can be rationally, commercially and/or effectively manufactured while still providing desirable performance characteristics for this type of glass. We have found that it requires the presence of tin oxide (SnO ₂ ) for this purpose. Since it is known in the art that large cationic species adversely affect high-frequency dielectric loss behavior in glasses (which is exactly the type of glass we are making here), the use of this element It should be noted that addition goes against the conventional wisdom of those skilled in the art. One example of a large cationic species that adversely affects high-frequency dielectric loss behavior in glasses is calcium oxide, whose desirable positive effects on glass compositions outweigh the negative effects, and thus limited quantities in these types of glasses. Included to the limit. Tin oxide is intentionally added to the glass formulations described herein and is three times the atomic weight of calcium oxide. Although it is generally understood by those skilled in the art that the addition of tin oxide gives worse results in this type of glass (i.e. significantly worse than calcium oxide due to the size difference), the inventors are surprised Interestingly, we have found that SnO ₂ up to an amount of 1.5 weight percent does not adversely affect the Df behavior of these glasses. Therefore, in one embodiment of the present invention, tin oxide is used in the present glass compositions as a fining agent to remove seeds and hollow filaments to improve their quality and performance, but not the desired low dielectric loss glass. It did not significantly affect the properties, which is contrary to the general opinion that tin oxide impairs this particular property.

Titanium oxide (TiO ₂ ) is optionally present or intentionally incorporated into the glass compositions 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. Still alternatively, the weight percent of titanium oxide is 5.0 or less. Titanium oxide above 6 weight percent appears to increase the propensity for phase separation in glass compositions and fibers, especially when combined with phosphorus pentoxide. Titanium oxide typically acts as a viscosity reducing agent and may be intentionally added or present as an impurity from conventional raw materials. As such, titanium oxide may be present in the glass composition at a weight percent of 0.01 or greater. Alternatively, titanium oxide may be present in the glass composition at a weight percent of 0.05 or greater. Still alternatively, titanium oxide may be present in the glass composition at a weight percent of 0.1 or greater. In some embodiments, titanium dioxide is present in the glass composition at less than 0.5 weight percent.

Since the proposed objective of the present invention is to produce the most stable glass reasonably possible for the melting and spinning process, _TiO2 below that, including 6 weight percent in this family, does not adversely affect _Tliq . It would not have been expected by those skilled in the art that this could be tolerated without producing delta T behavior (delta T<40° C.) that renders these glasses unspinnable. See page 37 of Wolfram Holland, et al., Glass Ceramic Technology, 2nd Edition, Wiley and Sons, July 2012.

_TiO2 is known in the art as an acceptable additive to other low _Dk glasses to reduce viscosity. In view of this, we would expect that any amount of nucleating agent (TiO ₂ , crystallization rate and possibly T _liq would be increased, but we also know that it would reduce the viscosity (T log3). ) was able to achieve an acceptable delta T range (T log3 to T _liq ) in the parent glass composition.

Interestingly, none of the relevant prior art presents any examples of combining _P2O5 with significant amounts of _SnO2 and _TiO2 , predicting any synergistic or desirable behavior _. It is difficult.

Additional oxides may be present in the glass fibers and compositions of the invention without departing from the scope of the 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 ), zirconium oxide (ZrO ₂ ), chromium oxide (Cr ₂ O ₃ ), iron oxide (Fe ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), manganese oxide (Mn ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ) and/or oxides such as vanadium oxide (V ₂ O ₃ ) may be present. Further, the sum of these additional oxides is no more than 3 weight percent of the total composition, provided they do not change the functionality of the glass. Alternatively, the sum of these additional oxides may be 2 weight percent or less of the total composition. Still alternatively, the sum of these additional oxides may be 1.5 weight percent or less of the total composition. Further alternatively, the sum of these additional oxides, in some embodiments of the invention, is 3.0 weight percent, 2.0 weight percent and/or 1.0 weight percent of the total composition. It may be below.

Since even a small amount of alkali metal oxides can have a great effect on the glass composition, the sum of alkali metal oxides such as Na ₂ O, K ₂ O and Li ₂ O should account for 1 part of the total composition. 0 weight percent or less is preferred. More preferably, the total is 0.5 weight percent or less of the total composition. More preferably, the total is no more than 0.25 weight percent of the total composition.

Examples of glass compositions and glass fibers of the invention are described herein. In one embodiment, the glass composition and/or glass fibers comprise 48.0 weight percent to 58.0 weight percent SiO ₂ , 15.0 weight percent to 26.0 weight percent B ₂ O ₃ , 12 . 0 to 18.0 weight percent Al ₂ O ₃ , greater than 0.25 to 3.0 weight percent P ₂ O ₅ , greater than 0.25 to 7.0 weight percent CaO,5. 0 weight percent or less MgO, greater than 0 weight percent to 1.5 weight percent SnO ₂ and 6.0 weight percent or less TiO ₂ . An alternative glass composition and/or glass fiber of the present invention is 49 weight percent to 57.5 weight percent SiO ₂ , 15.5 weight percent to 25.5 weight percent B ₂ O ₃ , 12.5 weight percent -17.5 weight percent Al ₂ O ₃ , >0.25 weight percent to 3.0 weight percent P ₂ O ₅ , >0.25 weight percent to 6.5 weight percent CaO, 4.50 weight percent % MgO, greater than 0 to 1.25 weight percent SnO ₂ and up to 5.5 weight percent TiO ₂ . Further alternative glass compositions and/or glass fibers of the present invention may include the following components: 50 weight percent to 57.0 weight percent SiO ₂ , 16.0 weight percent to 25.0 weight percent. weight percent B ₂ O ₃ , 13.0 weight percent to 17.0 weight percent Al ₂ O ₃ , greater than 0.25 weight percent to 3.0 weight percent P ₂ O ₅ , greater than 0.25 weight percent to 6.0 weight percent CaO, 4.0 weight percent or less MgO, greater than 0 weight percent to 1.00 weight percent SnO ₂ and 5.0 weight percent or less TiO ₂ .

The glass composition of the present invention has a liquidus temperature above 1000°C. In alternative embodiments, the glass composition may have a liquidus temperature above 1050°C. In further alternative embodiments, the glass composition may have a liquidus temperature above 1100°C. A liquidus temperature above 1000° C. or more preferably above 1050° C. is advantageous for spinning the glass composition according to the invention.

Additionally, the glass compositions of the present invention may have a T log3 viscosity temperature of greater than 1350°C. Alternatively, the glass composition may have a T log3 viscosity temperature greater than 1355°C. In a further alternative embodiment, the glass composition can have a T log3 viscosity temperature greater than 1360°C. A T log3 viscosity temperature of greater than 1350° C. is advantageous for spinning the glass composition according to the invention.

The glass fibers of the present invention may have a dielectric constant of 6 or less. Alternatively, the glass fiber may have a dielectric constant of 4.80 or less. In further alternative embodiments, the glass fiber may have a dielectric constant of 4.70 or less.

Additionally, the glass fibers of the present invention may have a loss factor of 38×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature. Alternatively, the glass fiber may have a loss factor of 30×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature. In a further alternative embodiment, the glass fibers of the present invention may have a loss factor of 28×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature.

The glass fibers of the present invention can be incorporated into glass fiber reinforced articles such as printed circuit boards. Additionally, the glass fibers of the present invention can be used in conjunction with products such as woven fabrics, nonwoven fabrics, unidirectional fabrics, chopped strands, chopped strand mats, composites and communication signal carrying media.

The present invention also includes a method of providing continuous manufacturable low dielectric glass fibers. The method comprises the steps of feeding a glass composition as disclosed herein into 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 a low dielectric constant and low loss factor glass fiber.

As discussed above, the composition of the glass to provide the low dielectric constant glass fibers is at least in part the weight percentages of the oxides discussed above, as well as silicon dioxide, aluminum oxide, boron oxide, calcium oxide, Based on the ratio and total weight of magnesium oxide, phosphorus oxide, tin oxide and/or titanium oxide. In one aspect, the combination of these parameters, in addition to other parameters discussed herein, such as T log3 viscosity temperature, results in a glass fiber having a low dielectric constant and a low loss factor as defined herein. It is possible to obtain

Compared to previous attempts in the field, Creux's formulation exemplifies glasses with completely inferior Df behavior (Df ~0.0090 at 10 GHz), as shown in two examples in US Pat. It is something to do. In contrast, the present invention achieves Df<0.0028. In addition, Creux has a T log3 of less than 1350°C and a T _liq of less than 1000°C.

Zhang, on the other hand, does not describe the Df behavior of the glass at all. The T log3 of Zhang's glass is less than 1350°C and the T _liq are all less than 1000°C. Interestingly, Zhang states that the glasses have excellent devitrification behavior because the primary crystals (wollastonite/diopside/calcium feldspar) are all in competition with each other. See paragraph [0014] of Patent Document 8.

Given that the state-of-the-art glass family has a T _liq of less than 1000° C. and a T log3 viscosity temperature of less than 1350° C., in order to achieve the presently described glass invention, if not all of the above prior art It is clear that it did not go as far as to combine most of them.

It is known in the art that the chemical composition primarily determines the primary crystals that devitrify from the glass melt. See Holland, page 4.

It is known in the art that _TiO2 is used by glass manufacturers as a nucleating agent to aid in glass crystallization and devitrification. See Holland at page 37. However, none of the prior art, including Mori, US Pat. We have not proven or demonstrated the effective use of _TiO2 with substantial and/or enormous amounts of _P2O5 and _SnO2 , which _we believe will produce unexpected effects.

Furthermore, the inventors have unexpectedly discovered that the measured dielectric loss of the present invention appears to be closely related to the crystallization behavior of the present glasses. That is, glasses with higher T _liq values tend to have better or lower Df properties.

To achieve the desired Df behavior (Df<0.0028 or <0.0027 or <0.0026, or even lower), the glasses defined by the recipes disclosed herein by the inventors are , tend to devitrify more easily, i.e. at higher T _liq values, eg above 1000°C. Furthermore, the most desirable Df values are at T _liq significantly higher than 1000°C.

The inventors have further surprisingly found that the most desirable glasses for obtaining low Df behavior crystallize in aluminoborate mullite (needle-like) crystals as the first devitrified phase, and have a unique tendency to form them. It was found that the network structure of

Zhang, on the other hand, states that his glasses form wollastonite, diopside and Ca-feldspar crystals, but not aluminoborate mullite.

We speculate that glasses that tend to be contained in this aluminoborate mullite primary region have inherently favorable network structures for both good glass formation and excellent (i.e. low) Df behavior. do.

Similar to Creux, the glass invented by Kuhn (US Pat. No. 5,730,900) also has poor Df behavior (Df≧0.0044), with only Example 1 out of the 6 examples being positive for acceptable fiber formation. (see Kuhn's Table II).

Having described generally herein the unexpectedly effective formulations along with our findings, further understanding can be obtained by reference to certain specific examples illustrated below. The examples are presented for illustrative purposes only and are not intended to be exhaustive or limiting unless otherwise specified.

Examples of glass compositions made in accordance with the present invention are described below. The specific ingredients and amounts thereof, and other conditions and details recited in these examples should not be construed to unduly limit this invention. In these examples, and throughout this specification, all percentages, parts and ratios are by weight (mass) unless otherwise indicated.

Exemplary glass compositions of the invention are shown in Tables 1-12 below. The liquidus temperature of the example glass composition is represented as "T _liq" and the temperature at which the glass composition had a viscosity of 1000 poise is represented as "T ₃ " (also referred to as "T log3" viscosity temperature ). The liquidus temperature and _T3 temperature of the example glass compositions were measured for some glass compositions and calculated for others. Example compositions were used to form glass fibers, and the dielectric constant and loss factor were measured for some glass fibers and calculated for others. Dielectric constants are expressed as "Dk" values and loss factors are expressed as "Df" values.

Batches having the sample glass compositions shown in Tables 1-12 are typically prepared as follows. Typically, glass synthesis involves batch pretreatment (mechanical and thermal), first melting, fritting or crushing in water, second melting, and finally pouring the glass into graphite molds.

Glass samples were typically tested for crystallization ability (liquidus temperature) according to ASTM C 829-81.

T log3 viscosity temperature was typically measured using ASTM C 965-81.

Dielectric property measurements at 10 GHz are typically performed using the Split Post Dielectric Resonator method, also referred to in the art as SPDR testing.

As shown in Tables 1-12, at 10 GHz, the example glass compositions have dielectric constants of 4.75 or less and loss factors of 28×10 ⁻⁴ or less. Specifically, at 10 GHz, the dielectric constant is between 4.34 and 4.75 and the loss factor is between 19×10 ⁻⁴ and 28×10 ⁻⁴ . Therefore, the glass compositions of the examples exhibited a low dielectric constant and a low loss factor that are lower than the dielectric properties of E-glass.

Additionally, the example glass compositions exhibited T log3 viscosity temperatures of 1352° C. to 1431° 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 spinning the glass composition according to the invention. Thus, the glass compositions according to the examples and according to embodiments of the invention exceed 1350°C.

Furthermore, the glass compositions of the examples exhibited liquidus temperatures of 1011°C to 1342°C. Having a liquidus temperature above 1000° C., or in some embodiments above 1050° C., is sufficient for spinning the glass composition according to the present invention. Thus, the glass compositions according to the examples and according to embodiments of the invention exceed 1000°C.

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. The glass fibers are particularly suitable for reinforcing printed wiring boards for high density circuits used in high speed routing systems. Additionally, the glass compositions used to make the fibers of the present invention have excellent processability. Therefore, stable low-dielectric glass fibers can be easily produced.

A variety of substrates comprising the glass fibers of the present invention can be produced including, but not limited to, wovens, nonwovens, unidirectional fabrics, knitted products, chopped strands, rovings, filament wound products, glass powders and mats. can. Composite materials formed from at least one of these substrates and a plastic resin matrix (thermosetting plastics, composite thermoplastics, sheet molding compounds, bulk molding compounds, prepregs, etc.) are also used to strengthen peripheral communication devices and the like. be able to. For example, composite materials containing glass fibers according to the present invention can be used in radar transmission applications at frequencies ranging from about 300 MHz to about 30 GHz.

The methods disclosed and described relate to glass fibers. Glass fibers can be obtained by mechanically dampening a stream of molten glass flowing out of an opening located at the base of a spinning bushing powered by resistive heating or other means. These glass fibers may be of particular interest for the production of meshes and fabrics used in composites with organic and/or inorganic matrices.

As required, detailed embodiments of the present invention are disclosed herein. However, it is to be understood that the disclosed embodiments, which may be embodied in various and alternative forms, are merely exemplary of the invention. Therefore, the specific structural and functional details disclosed herein are not to be construed as limiting, but merely as a basis for the claims and to teach those skilled in the art to various uses of the invention. It is interpreted as representative grounds for It will be appreciated by those skilled in the art that many changes and substitutions can be made to the above description of preferred embodiments and examples without departing from the spirit and scope of the invention as defined by the appended claims. it is obvious.

Various embodiments and examples of the invention have been described above, and these descriptions are presented for purposes of illustration and description. Variations, modifications, modifications and deviations from the above disclosed embodiments, systems and methods may be employed without departing from the spirit and scope of the present invention.

Claims (19)

A glass composition,
48.0 weight percent to 58.0 weight percent _SiO2 ,
15.0 weight percent to _26.0 weight percent _B2O3 ;
12.0 weight percent to 18.0 weight percent Al ₂ O ₃ ;
more than 0.25 weight percent to _3.0 weight percent _P2O5 ;
more than 0.25 weight percent to 7.0 weight percent CaO;
5.0 weight percent or less of MgO,
consisting essentially of greater than 0 weight percent to 1.5 weight percent SnO ₂ , and
containing not more than 6.0 weight percent _TiO2 ,
A glass composition having a glass viscosity of 1000 poise at temperatures above 1350°C and a liquidus temperature above 1000°C. further comprising from 49.0 weight percent to 57.5 weight percent _SiO2 ;
further comprising 15.5 weight percent to _25.5 weight percent _B2O3 ;
further comprising 12.5 weight percent to 17.50 weight percent Al ₂ O ₃ ;
further comprising from greater than 0.25 weight percent to _3.0 weight percent _P2O5 ;
further comprising from greater than 0.25 weight percent to 6.5 weight percent CaO;
further comprising no more than 4.5 weight percent MgO;
consisting essentially of greater than 0 weight percent to 1.25 weight percent SnO ₂ , and
further comprising no more than 5.5 weight percent _TiO2 ;
A glass composition according to claim 1 . further comprising from 50.0 weight percent to 57.0 weight percent _SiO2 ;
further comprising 16.0 weight percent to _25.0 weight percent _B2O3 ;
further comprising 13.0 weight percent to 17.0 weight percent Al ₂ O ₃ ;
further comprising from greater than 0.25 weight percent to _3.0 weight percent _P2O5 ;
further comprising from greater than 0.25 weight percent to 6.0 weight percent CaO;
further comprising 4.0 weight percent or less of MgO;
consisting essentially of greater than 0 to 1.0 weight percent SnO ₂ , and
further comprising no more than 5.0 weight percent _TiO2 ;
A glass composition according to claim 1 . 49.0 weight percent or more of _SiO2 ,
57.5 weight percent or less of _SiO2 ;
15.5 weight percent or more _{B2O3 ,}
25.5 weight percent or less _{B2O3 ,}
12.50 weight percent _or more _Al2O3 ,
17.50 weight percent or less Al ₂ O ₃ ,
greater than 0.25 weight percent _{P2O5 ;}
3.0 weight percent or less _{P2O5 ;}
greater than 0.25 weight percent CaO;
6.5 weight percent or less CaO;
4.5 weight percent or less MgO;
more than 0 weight percent _SnO2 ,
1.25 weight percent or less of _SnO2 , and/or
5.5 weight percent or less _TiO2 ,
2. The glass composition of claim 1, further comprising one or more of: 50.0 weight percent or more of _SiO2 ,
57.0 weight percent or less of _SiO2 ;
16.0 weight percent or more _{B2O3 ,}
25.0 weight percent or less _{B2O3 ,}
13.0 weight percent or more Al ₂ O ₃ ,
Al ₂ O ₃ up to 17.0 weight percent;
greater than 0.25 weight percent _{P2O5 ;}
3.0 weight percent or less _{P2O5 ;}
greater than 0.25 weight percent CaO;
6.0 weight percent or less CaO;
4.0 weight percent or less MgO;
more than 0 weight percent _SnO2 ,
1.0 weight percent or less SnO ₂ , and/or
5.0 weight percent or less _TiO2 ,
2. The glass composition of claim 1, further comprising one or more of: 2. The glass composition of claim 1, wherein as the first devitrified phase, the glass composition has a unique network structure that is prone to crystallize and form aluminoborate mullite crystals. supplying the glass composition of claim 1 to a melting zone of a glass melting furnace;
heating the composition to a molding temperature above the liquidus temperature;
continuously spinning the molten glass to produce glass fibers with a low dielectric constant and a low loss factor;
A method of providing a continuous manufacturable low dielectric glass fiber comprising: 48.0 weight percent to 58.0 weight percent _SiO2 ,
15.0 weight percent to _26.0 weight percent _B2O3 ;
12.0 weight percent to 18.0 weight percent Al ₂ O ₃ ;
more than 0.25 weight percent to _3.0 weight percent _P2O5 ;
more than 0.25 weight percent to 7.00 weight percent CaO;
5.0 weight percent or less of MgO,
consisting essentially of greater than 0 weight percent to 1.5 weight percent SnO ₂ , and
containing not more than 6.0 weight percent _TiO2 ,
A low dielectric glass fiber having a glass viscosity of 1000 poise at temperatures greater than 1350°C and formed from a glass composition having a liquidus temperature greater than 1000°C. The glass composition is
further comprising from 49.0 weight percent to 57.5 weight percent _SiO2 ;
further comprising 15.5 weight percent to _25.5 weight percent _B2O3 ;
further comprising 12.5 weight percent to 17.50 weight percent Al ₂ O ₃ ;
further comprising from greater than 0.25 weight percent to _3.0 weight percent _P2O5 ;
further comprising from greater than 0.25 weight percent to 6.5 weight percent CaO;
further comprising no more than 4.5 weight percent MgO;
consisting essentially of greater than 0 weight percent to 1.25 weight percent SnO ₂ , and
further comprising no more than 5.5 weight percent _TiO2 ;
The low dielectric glass fiber according to claim 8. The glass composition is
further comprising from 50.0 weight percent to 57.0 weight percent _SiO2 ;
further comprising 16.0 weight percent to _25.0 weight percent _B2O3 ;
further comprising 13.0 weight percent to 17.0 weight percent Al ₂ O ₃ ;
further comprising from greater than 0.25 weight percent to _3.0 weight percent _P2O5 ;
further comprising from greater than 0.25 weight percent to 6.0 weight percent CaO;
4.0 weight percent or less of MgO,
consisting essentially of greater than 0 to 1.0 weight percent SnO ₂ , and
further comprising no more than 5.0 weight percent _TiO2 ;
The low dielectric glass fiber according to claim 8. The glass composition is
49.0 weight percent or more of _SiO2 ,
57.5 weight percent or less of _SiO2 ;
15.5 weight percent or more _{B2O3 ,}
25.5 weight percent or less _{B2O3 ,}
12.5 weight percent or more Al ₂ O ₃ ,
17.50 weight percent or less Al ₂ O ₃ ,
greater than 0.25 weight percent _{P2O5 ;}
3.0 weight percent or less _{P2O5 ;}
greater than 0.25 weight percent CaO;
6.5 weight percent or less CaO;
4.5 weight percent or less MgO;
more than 0 weight percent _SnO2 ,
1.25 weight percent or less of _SnO2 , and/or
5.5 weight percent or less _TiO2 ,
9. The low dielectric glass fiber of claim 8, further comprising one or more of: The glass composition is
50.0 weight percent or more of _SiO2 ,
57.0 weight percent or less of _SiO2 ;
16.0 weight percent or more _{B2O3 ,}
25.0 weight percent or less _{B2O3 ,}
13.0 weight percent or more Al ₂ O ₃ ,
Al ₂ O ₃ up to 17.0 weight percent;
greater than 0.25 weight percent _{P2O5 ;}
3.0 weight percent or less _{P2O5 ;}
greater than 0.25 weight percent CaO;
6.0 weight percent or less CaO;
4.0 weight percent or less MgO;
more than 0 weight percent _SnO2 ,
1.0 weight percent or less of _SnO2 and/or
5.0 weight percent or less _TiO2 ,
9. The low dielectric glass fiber of claim 8, further comprising one or more of: 9. 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. 9. The glass fiber according to claim 8, having a dielectric constant of 4.80 or less and/or a loss factor of 30×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature. 9. The glass fiber according to claim 8, having a dielectric constant of 4.70 or less and/or a loss factor of 28×10 ⁻⁴ or less at a frequency of 10 GHz at room temperature. A glass fiber reinforced article comprising the glass fiber of claim 8. 17. The glass fiber reinforced article of claim 16, which is a printed circuit board. 9. The glass fiber of claim 8, formed from a glass composition having a unique network structure that tends to crystallize and form aluminoborate mullite crystals. 9. A product comprising glass fibers 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 carrying media.