QUARTZ GLASS YARN AND QUARTZ GLASS FABRIC

Abstract

Quartz glass yarn having a yarn bending density of 0.10 pieces / cm or less, determined by the number of yarn bends of the quartz glass yarn per unit length of the quartz glass yarn, wherein the yarn bends each have a bending point with a radius of curvature of 5 mm or less and a bending angle of 120° or less, wherein quartz glass filaments form the quartz glass yarn and are obtained by spinning a quartz glass block with a diameter of 100 to 200 mm and a roundness of 50 µm or less, wherein the roundness is defined by a difference between the radii of two concentric geometric circles, when a circular cross-section of the quartz glass block lies between the two concentric geometric circles and the distance between the two concentric geometric circles is minimal, wherein the quartz glass filaments each have a filament diameter of 3.0 µm to 10.0 µm, wherein the number of quartz glass filaments is from 20 to 300, and where the number of twists of the quartz glass yarn ranges from 4 twists / m to 24 twists / m.

Description

Technical field

[0001] The present invention relates to a quartz glass yarn and a quartz glass fabric which can be used in a suitable manner in a high-frequency printed circuit board. State of the art

[0002] The 5th generation mobile communications standard, scheduled to go live in 2020, will use a high frequency in the 28 GHz band in addition to the currently used 6 GHz band or below. Furthermore, the 6th generation mobile communications standard, the next generation of mobile communications, will also utilize a portion of a high frequency in the millimeter wave band.

[0003] In addition to mobile communication and the widespread use of IoT / M2M, the frequency of the electronic circuits that make up all network devices is increasing in response to the rapidly growing volume of data in the field of data communication. For example, IEEE 802ad, one of the WiFi communication standards currently under development, uses the 60 GHz band.

[0004] In a high-frequency printed circuit board (PCB) for use in communication and networking devices that can be adapted to such high frequencies, low-loss and low-latency signal processing is required. Furthermore, a glass fabric with a low dielectric constant and low loss is necessary for the high-frequency PCB.

[0005] For example, patent document 1 proposed a quartz glass fabric with excellent surface smoothness, less variation in mass and thickness, and excellent dimensional stability, obtained by controlling the feed rate of an ingot serving as raw material for a thick quartz glass fiber into an oven and controlling the drawing rate of the thick quartz glass fiber serving as raw material for a quartz glass filament.

[0006] Meanwhile, in addition to increasing the data transmission rate, the data transmission system between network devices has also changed from a conventional parallel transmission system to a fast differential serial transmission system, and, in addition to a low dielectric constant and low loss, signal transmission speed through stabilization of a characteristic impedance has become an important factor in the high-frequency printed circuit board.

[0007] For example, patent document 2 proposed the design of a multi-layer printed wiring system that ensures signal quality and enables satisfactory high-speed signal transmission by designing the wiring using diagonal wiring to reduce impedance changes and propagation delay differences caused by differences in the specific dielectric constant between a glass fabric and a resin, thereby addressing and finding a solution to the problem of a secondary resonant frequency. State of the art document (patent document) Patent document 1: JP 2016 - 11 484 A Patent document 2: JP 2016 - 207 776 A Disclosure of the invention Problems to be solved by the invention

[0008] In the case of patent document 1, a quartz glass fabric with a low dielectric constant and low loss is achieved, but with regard to its use in the high-frequency printed circuit board, in addition to the above considerations, a signal transmission speed is required by stabilizing a characteristic impedance.

[0009] Furthermore, in the case of patent document 2, a difference in dielectric properties caused by a change in the specific dielectric constant depending on location due to the distribution state of the glass fibers and a resin present in a cross-sectional direction is avoided not by a change in the physical properties of the glass fabric itself, but by a circuit arrangement. Therefore, the difference in the specific dielectric constant between the glass fabric and the resin present in the printed circuit board itself is not reduced.

[0010] The present invention was conceived with regard to the aforementioned circumstances, and it is an object of the present invention to provide a quartz glass yarn and a quartz glass fabric which, in addition to a low dielectric constant and low loss, have a signal transmission speed that is stabilized by stabilizing a wave impedance. Means to solve the problem

[0011] The inventors of the present invention have conducted extensive investigations to solve the aforementioned problems and have determined that, with regard to the quartz glass fabric forming the high-frequency printed circuit board, the flatness and defects of the quartz glass fabric are significantly contributing to these problems. Furthermore, the inventors of the present invention have determined, in light of these considerations, that it is important for the quartz glass yarn used as raw material to have a low number of bending points attributable to yarn bending (or its bending behavior during unwinding) in order to achieve the present invention.

[0012] That is, according to one embodiment of the present invention, a quartz glass yarn is provided which has a yarn bending density of 0.10 pieces / cm or less of yarn bends, each having a bending point with a radius of curvature of 5 mm or less and a bending angle of 120° or less.

[0013] Preferably, the quartz glass yarn has a tensile strength of 2.0 GPa or more, and the quartz glass filaments forming the quartz glass yarn each have an initial breaking strength of 80.0% or more of the tensile strength of the quartz glass yarn.

[0014] Suitablely, the quartz glass filaments forming the quartz glass yarn each have a filament diameter of 3.0 µm to 10.0 µm, a number of quartz glass filaments of 20 to 300, and a number of twists of the quartz glass yarn of 4 twists / m to 24 twists / m.

[0015] According to a further embodiment of the present invention, a quartz glass fabric is provided which is produced by weaving and opening using the quartz glass yarn according to one embodiment of the present invention.

[0016] Preferably, the quartz glass fabric has a mean fabric thickness measured with an electronic micrometer under a measuring pressure of 63.2 kPa of 100% to 110% of a mean fabric thickness measured with the electronic micrometer under a measuring pressure of 157.9 kPa.

[0017] Suitablely, the quartz glass fabric exhibits a coefficient of variation of fabric thickness, measured with an electronic micrometer under a pressure of 63.2 kPa, within 10%. Advantageous effects of the invention

[0018] According to the present invention, by using the quartz glass yarn in which the number of bending points attributed to the yarn structure is low, a quartz glass fabric with excellent flatness and a signal transmission speed stabilized by stabilizing a wave impedance, as well as a low dielectric constant and low loss, can be provided. Brief description of the drawings Fig. Figure 1 shows an explanatory view illustrating yarn bends of a quartz glass yarn. Fig. Figure 1 shows (a) an enlarged schematic view to illustrate a method for measuring yarn bending, and (b) to (d) each show an enlarged view of a main part of (a). Fig.Figure 2 shows a schematic representation of an electric resistance heating oven configured to produce a thick quartz glass fiber used in Example 1. Fig. Figure 3 shows an explanatory view of the schematic representation of a process used in Example 1 for the production of quartz glass filaments. Fig. Figure 4 shows a cross-sectional view of gas supply sections of a modified electric resistance heating oven used in Example 1. Fig. Figure 5 shows a cross-sectional view of a gas supply section of a conventional furnace. Fig. Figure 6 shows an explanatory diagram that schematically depicts a stress-strain curve of a quartz glass yarn. Fig.Figure 6 is (A) an explanatory diagram showing a case where all the quartz glass filaments have the same tensile strength, and (B) is an explanatory diagram showing a case where there are differences in the tensile strength of the quartz glass filaments. Fig. Figure 7 shows an explanatory view for the schematic representation of the flatness of a quartz glass fabric in the case where it is assumed that the quartz glass fabric is eventually opened. Fig. Figure 8 shows a cross-sectional view of a wave impedance measuring plate made of the quartz glass fabric of the present invention. Description of the embodiments

[0019] The present invention is described in detail below. (1) Quartz glass yarn

[0020] As used herein, a thin thread-like single fiber obtained by drawing quartz glass is defined as a “quartz glass filament”, the bundled quartz glass filaments as a “quartz glass strand”, and the bundled and twisted quartz glass strands as a “quartz glass yarn”.

[0021] The quartz glass yarn of the present invention has a yarn bending density of 0.10 pieces / cm or less, preferably 0.08 pieces / cm or less, more preferably 0.05 pieces / cm or less.

[0022] Fig. Figure 1 shows an explanatory view illustrating the bending of the quartz glass yarn. Fig. Figure 1 is (a) an enlarged schematic view illustrating a method for measuring yarn bending, and (b) to (d) are each an enlarged view of a main part of (a). Fig. Figure 1 shows a quartz glass yarn 10. A bending point 12 of the quartz glass yarn is shown. Fig.Figure 1 is the bending point 12 of the quartz glass yarn, which is attributed to a yarn bend, and is marked by the outlined circle. A curved section 13 is shown, which is not the bending point of the present application. The yarn bend of the quartz glass yarn 10 of the present invention is a large arc, which is observed when the yarn is slightly loosened. The yarn bend is measured as follows. A radius of a curve formed in the quartz glass yarn is defined as the radius of curvature, and a bending section with a curve having a radius of curvature of 5 mm or less and a bend with a bend angle of 120° or less is defined as the bending point. The number of bending points is measured as the number of yarn bends in order to calculate a yarn bend density.

[0023] Specifically, the quartz glass yarn wound in the outermost layer of a spool (10) is used as the test yarn. When testing the yarn bend of the quartz glass yarn wound around the spool, the quartz glass yarn in the outermost layer is tested for the following reason: If the test yarn is taken from the quartz glass yarn wound in a middle layer, the quartz glass yarn wound in a layer on the outside of the middle layer must be removed, which is wasteful. Furthermore, there is a risk of measurement error due to the influence of winding pressure on the quartz glass yarn wound in the layer on the outside of a sample section.

[0024] After an upper end section of the quartz glass yarn 10 has been fixed with fasteners, the quartz glass yarn 10 is pulled with such a force that it is not stretched, but straightened at an initial force of 2.94 mN, as described in a) of “5.1 Initial Load” of “5. test method” of JIS L 1013: 2010 “Testing Methods for Man-made Fiber Filament Yarns”. In this state, a lower end section of the quartz glass yarn 10 is fixed with fasteners so that a fastening distance L of 400 mm is achieved. Subsequently, while the upper and lower ends of the quartz glass yarn 10 are being fastened, the distance between the upper and lower ends is reduced by 1 mm (0.25%) to adjust the fastening distance L to 399 mm. As the fastening distance is reduced, the pulled quartz glass yarn 10 is loosened. Images of the quartz glass filament in this state are taken in all directions.Using image analysis software, the radius of curvature r and the bending angle θ of each bend formed in the quartz glass yarn 10 are measured. Bend segment 12 with a radius of curvature r of 5 mm or less and a bending angle θ of 120° or less is defined as a bend point, and the number of bend points is counted. Small bends with a radius of curvature r greater than 5 mm or a bending angle θ greater than 120° are not counted as yarn bends. From the measured images in all directions, the results from the image with the highest number of bend points are used. The number of bend points is defined as the number of yarn bends in the quartz glass yarn, and thus the yarn bend density can be calculated.

[0025] Fig. 1(b) to Fig.Figure 1(d) each shows an explanatory view illustrating the schematic representation of the radius of curvature r or the bending angle θ of the curved section formed in the quartz glass yarn 10. As in Fig. As shown in Figure 1(d), the bending point 12 attributed to the yarn bend, as used here, refers to the bending section that has a bend with a radius of curvature r of 5 mm or less and a bending angle θ of 120° or less. The bending point 12 is represented by the bending point 12, which is attributed to the yarn bending, as used here. Fig. The curved section 13 shown in 1(b) has a radius of curvature r of more than 5 mm and is therefore not the bending point in the present application. Similarly, the section shown in Fig. 1(c) The curved section 13 shown has a bending angle θ of more than 120° and is therefore not the bending point in the present application.

[0026] If the yarn bending density exceeds 0.1 pieces / cm², there is a risk of the quartz glass yarns becoming intertwined, reducing the flatness of the resulting quartz glass fabric. Furthermore, the interlacing of the quartz glass yarns impairs slippage, making it difficult to achieve the desired effect of the post-weaving openwork treatment and further reducing the flatness of the quartz glass fabric after the treatment. The lower limit for yarn bending density is 0.00 pieces / cm², as it is preferable for the quartz glass yarn to have no bending point attributable to yarn bending.

[0027] Quartz glass yarn has a softening point of 1,600°C to 1,710°C, which is significantly higher than that of other types of glass (e.g., E-glass has a softening point of 840°C). Therefore, quartz glass yarn has the following properties. When the glass is processed into a filament form, all filaments are cooled immediately, resulting in brittle filaments with insufficient flexibility and the potential for yarn bending.

[0028] When quartz glass yarn is woven, a high tension is applied to the yarn during the weaving process, but this tension is released after weaving. In this case, if a quartz glass yarn with a high yarn bend density (with a large number of bend points attributed to the yarn bends) is used, the yarn bends remain as tiny surface irregularities even after the quartz glass yarn is transformed into a quartz glass fabric and persist even after subsequent opening treatment, without improvement. Therefore, to obtain a quartz glass fabric with high flatness, it is preferable to have a low yarn bend density (a small number of bend points attributed to the yarn bends).

[0029] In the present invention, a quartz glass fabric is produced by weaving using quartz glass yarns, each of which has a small number of flex points resulting from the yarn bends. This reduces the interweaving between the quartz glass yarns in the fabric, thereby achieving a smoother surface. Furthermore, the slippage between the quartz glass yarns is improved due to the reduced interweaving. This allows for efficient opening treatment, and as a synergistic effect, a flat and stable quartz glass fabric can be produced.

[0030] From the perspective of avoiding defects such as lint when weaving the quartz glass yarns, or from the perspective of being able to achieve sufficient opening performance when opening the woven quartz glass fabric at a suitable water pressure, the tensile strength of the quartz glass yarn is preferably 2.0 GPa or more, more preferably 2.4 GPa or more, and even more preferably 2.7 GPa or more.

[0031] As used here, the tensile strength of the fused silica yarn is measured according to a method specified in "7.4 Tensile Strength", in particular "7.4.3 Glass Yarn and Roving" in JIS R 3420: 2013 "Testing Methods for Textile Glass Products". In the present application, of the three tensile test methods described in 7.4.1 of the same JIS R 3420, "a) Constant-rate-of-extension Type Tensile Testing Method (CRE)" is adopted. An arithmetic mean of the breaking forces in Newtons (N) is calculated from the breaking forces of ten test specimens. Furthermore, the stress is divided by the cross-sectional area of ​​the fused silica yarn (sum of the cross-sectional areas of the fused silica filaments that make up the fused silica yarn), and the result is converted into a compressive strength. The compressive strength is defined as the tensile strength.

[0032] A specific strength distribution of the quartz glass filaments in the quartz glass yarn of the present invention is an important factor in preventing partial breakage of the quartz glass yarn. Partial breakage of the quartz glass yarn manifests as yarn fuzz, which becomes a quality problem. During weaving, the quartz glass fuzz leads to thread breaks, hindering the weaving process. Even if the fuzz does not cause thread breakage, it remains as fabric fuzz and causes an insulation defect in a printed circuit board that uses the fabric.

[0033] However, a quartz glass yarn in which fuzz formation is observed at one yarn stage can be sorted out in an inspection step, so that there is less of a direct impact on the flatness and fuzz formation of the quartz glass fabric. Rather, the problem arises that the quartz glass yarn partially tears in a weaving step and an opening step, and thus causes fuzz due to the strength distribution of the quartz glass filaments present in the quartz glass yarn.

[0034] Particularly during the opening process, where the fibers slide against each other using a high-pressure water jet, intense pressure is exerted on the quartz glass yarn itself. Therefore, if a weak filament is partially present within the quartz glass yarn, it can lead to partial breakage of the yarn.

[0035] If a low-strength filament is present in the quartz glass yarn, the originally required pressure conditions cannot be set to prevent partial breakage, thus reducing the flatness of the resulting quartz glass fabric.

[0036] In view of this, according to the present invention, such a partial fracture of the quartz glass yarn is predicted in advance by examining a stress-strain curve in a fracture test of the quartz glass yarn, thus obtaining a quartz glass yarn with fewer surface defects.

[0037] Fig. Figure 6 is an explanatory diagram that schematically shows the stress-strain curve of the quartz glass yarn. Fig. Figure 6 is (A) an explanatory diagram showing a case where all the quartz glass filaments have the same tensile strength, and (B) an explanatory diagram showing a case where there are differences in the tensile strength of the quartz glass filaments.

[0038] As used here, the stress-strain curve is a curve obtained by applying a strain to the quartz glass yarn (strain: a value obtained by dividing a distance between the handles by a handle spacing of 250 mm, expressed as a percentage) on the horizontal axis and applying a stress (stress applied between the ends of the quartz glass yarn) on the vertical axis, as shown in FIG. 6, according to the “a) Constant-rate-of-extension Type Tensile Testing Method (CRE)”, specified in a) of “7.4 Tensile Strength” of JIS R 3420: 2013 “Testing Methods for Textile Glass Products”.

[0039] If all the quartz glass filaments that make up the quartz glass yarn have the same tensile strength, the quartz glass yarn will break all at once at a certain stress, as in Fig.6(A) shown. A value obtained by converting the stress at which the quartz glass yarn breaks into a pressure is the tensile strength in the present application.

[0040] However, the quartz glass filaments that form the quartz glass yarn actually exhibit different strengths. In this case, the quartz glass filaments with lower strength break one after the other as the tension increases. As in Fig.As shown in Figure 6(B), the fracture of a portion of the quartz glass filaments reduces the essential cross-sectional area of ​​the quartz glass yarn and increases the stress (combined with pressure) applied to the quartz glass yarn. Therefore, the rate of slope of the stress (slope of the curve) to strain on the stress-strain curve changes. Consequently, an inflection point is created in the stress-strain curve. This inflection point was defined as the predetermined breaking point. A value obtained by dividing the stress at the breaking point by the cross-sectional area of ​​the quartz glass yarn at the beginning of the tensile test and converting the result into a compressive force was termed the "break point strength." Of the break points, an initial break point was defined as the initial break point, and the strength at the break point was defined as the initial break strength.Partial fracture of the quartz glass filaments occurred at any point between the initial fracture strength and the tensile strength, and therefore the strength at the initial fracture point was determined based on the tensile strength of the quartz glass yarn.

[0041] From the perspective of preventing partial breakage of the quartz glass yarn, the initial breakage point of the quartz glass yarn is important.

[0042] From the perspective of decreasing strength variations in the quartz glass filaments, the initial breaking strength of the quartz glass filament is preferably 80.0% or more, more preferably 85.0% or more, and even more preferably 90.0% or more of the tensile strength of the quartz glass yarn. The upper limit of the initial breaking strength of the quartz glass filament is 100.0%.

[0043] From the point of view of the thickness of the quartz glass fabric, the filament diameter of the quartz glass filament used in the quartz glass yarn of the present invention is preferably from 3.0 µm to 10.0 µm, more preferably from 3.5 µm to 7 µm.

[0044] The filament diameter of the quartz glass filament was measured as described below. The quartz glass yarn was cut, and a cut surface was photographed with an electron microscope. The diameter of the cut surface in the photograph was then measured with calipers and converted based on the magnification to calculate the filament diameter.

[0045] Furthermore, the number of filaments of the quartz glass filaments is preferably 20 to 300, more preferably 25 to 200, and even more preferably 30 to 150, depending on the thickness of the quartz glass fabric or the strength of the quartz glass yarn.

[0046] The SiO2 composition in the quartz glass filament is preferably from 98.0 wt% to 100.0 wt%, more preferably from 99.0 wt% to 100.0 wt%, and even more preferably from 99.5 wt% to 100.0 wt%.

[0047] A method for producing the quartz glass filament used in the quartz glass yarn according to the invention comprises spinning a quartz glass block to the desired roundness using a known spinning process. To obtain a quartz glass yarn with a low yarn bending density, it is not sufficient to merely control the feed rate of the quartz glass blank, which serves as raw material for thick quartz glass fibers, into an oven and to control the winding rate of the quartz glass filaments, as described in patent document 1. It is also necessary to ensure sufficient roundness of a cross-section of the quartz glass blank serving as raw material. In the case of a quartz glass block of 100 to 200 mm according to the invention, the quartz glass block is precisely polished so that the roundness reaches 50 µm or less. The roundness is preferably 30 µm or less, more preferably 20 µm or less.

[0048] A quartz glass blank with the desired roundness is obtained, for example, by cylindrical grinding on a cylindrical grinding machine. Specifically, the surface of the quartz glass blank is ground while the blank is held at both ends of a chuck on the cylindrical grinding machine and slowly moved by means of a rotating grinding wheel. In this case, the cylindrical grinding is performed several times, for example, in a roughing step and a finishing step, whereby the roughness and the cutting depth of the grinding wheel are varied and adjusted. In particular, the quartz glass block is processed in the roughing step using a rotary grinding wheel that has a roughness of preferably #100 / 120 to #140 / 170, more preferably #120 / 140, when expressed by the JIS grit size, such that the cutting depth preferably reaches 0.010 mm to 0.030 mm, more preferably 0.015 mm to 0.025 mm.In the subsequent finishing step, the result is machined using a rotary grinding wheel with a roughness of preferably #230 / 270 to #325 / 400, more preferably #270 / 325, expressed by the JIS grit size, so that the cut surface preferably reaches 0.005 mm to 0.010 mm, more preferably 0.006 mm to 0.009 mm. After the initial cylindrical grinding, a 10 mm thick sample is cut from the quartz glass ingot and its roundness is measured. This process of returning the sample to the next cylindrical grinding is repeated several times to obtain a quartz glass block with the desired roundness.

[0049] As used here, the roundness of the quartz glass ingot refers to the degree of deviation of a circular shape from a geometrically correct circle, as defined in "4.3 Roundness" in JIS B 0621: 1984 "Definitions and Designations of geometrical Deviations". Specifically, as defined in "5.3 Roundness", the roundness of the quartz glass ingot refers to the difference between the radii of two concentric geometric circles when a circular shape lies between the two circles and the distance between the two circles is minimal. In the JIS, the unit of roundness is expressed in mm or µm. However, in the present application, the roundness is a very small value, and therefore the unit of roundness is expressed in µm.

[0050] The roundness can be measured with a roundness measuring instrument (e.g. ROUND TEST RA-2200 AS, manufactured by Mitutoyo Corporation) that complies with JIS B 7451: 1997 “Instruments for the Assessment of Departure from Roundness”, by cutting the quartz glass ingot used as raw material into a thickness of 10 mm.

[0051] As a method for producing quartz glass yarn, for example, as in Fig.As shown in Figure 2, a quartz glass block 20 with the desired roundness and a diameter of 50 mm to 200 mm is heated and drawn in an electric resistance heating oven 42 to produce a thick quartz glass fiber 43 with a diameter of 100 µm to 300 µm. In this case, it is suitable that the outer diameter of the thick quartz glass fiber is measured with a laser outer diameter measuring device 44 and that the insertion speed V1 of the quartz glass block 20 into the electric resistance heating oven and the winding speed V2 of the thick quartz glass fiber are subjected to feedback control. Fig.Figure 2 shows a high-precision winding machine M configured to wind the thick quartz glass fiber 43. Also shown are a core tube 46, a gas inlet tube 48, a winding speed control unit 61 configured to control the winding speed of the thick quartz glass fiber 43, and a block feed speed control unit 62 configured to control the feed speed of the quartz glass block 20.

[0052] Furthermore, when drawing thick quartz glass fibers, local variations in the outer diameter of the fibers result in a strength distribution within the final quartz glass filament. Therefore, to suppress these local variations, it is preferable to implement measures to minimize temperature variations within the electrical resistance heating furnace. Specifically, it is advisable to ensure that the temperature uniformity within the furnace is not disrupted by the inert gas, taking into account the type of inert gas to be introduced to protect the heating element, the introduction path, the gas flow rate, and other relevant factors.

[0053] For example, it is preferable that the number of introduction paths for a protective gas, such as nitrogen gas, into the electric resistance heating oven be reduced from one path according to the state of the art ( Fig. 5) via several routes (four gas inlet pipes in Fig. 4) is increased and the gas flows through the four gas inlet pipes 48, which are equipped with independent pressure regulators and independent flow meters, so that the gas flow rate from each part from a lower section to an upper section of the electric resistance heating oven becomes uniform.

[0054] A quartz glass strand is produced from the manufactured thick quartz glass fiber 43, as described below. As in Fig.As shown in Figure 3, a multitude of thick quartz glass fibers 43, each with a diameter of 100 µm to 300 µm, are fed into the burner flame F1, which is supplied by a burner B1 with a wide hydrogen-oxygen flame. The feed rate is controlled by adjusting the rotational speed of a feed roller 53. Simultaneously, the thick quartz glass fibers 43 are wound onto a winder 49, while, from the opposite direction of the burner, they are bundled by a coating applicator 50 and a condenser 47. In this way, the thick quartz glass fibers 43 are heated and drawn into 30 to 100 quartz glass filaments 14. A coating agent is applied to the quartz glass filaments 14 by the coating applicator 50, and the quartz glass filaments 14 are then condensed by the condenser 47 to produce a quartz glass strand 18. The produced quartz glass strand 18 is then wound up with the winder 49.This process yields quartz glass filaments 14 with a diameter of 3.0 µm to 10.0 µm each.

[0055] The quartz glass yarn of the present invention can be produced by twisting the quartz glass strand with a predetermined number of turns using a twisting machine.

[0056] From the point of view of the ease of opening the quartz glass fabric (opening is easier because the number of twists is lower) and the strength of the quartz glass yarn (strength is higher because the number of twists is greater), the number of twists is preferably from 4 twists / m to 24 twists / m, more preferably from 4 twists / m to 16 twists / m, and even more preferably from 4 twists / m to 12 twists / m.

[0057] To reduce the strength distribution of the quartz glass filaments that make up the quartz glass yarn across all production stages, it is also preferable to consider deformations and defects in the capacitor (spinning step), the spiral wire (spinning step), the yarn guide (twisting step), and the feed unit (twisting step) that occur during spinning or twisting in a yarn path. In particular, the quartz glass yarn is very hard and brittle and therefore prone to damage to the parts with which it comes into contact. The quartz glass yarn itself can also be damaged. Therefore, it is desirable that parts that come into contact with the quartz glass filaments and the quartz glass yarn are always thoroughly inspected, and if defects are found, they should be immediately replaced with non-defective components. (2) Quartz glass fabric

[0058] The quartz glass fabric of the present invention is produced using the quartz glass yarn of the present invention. There is no particular restriction on a method for producing the quartz glass fabric, and the quartz glass fabric can be produced by a known method. Specifically, the quartz glass fabric of this invention is a fabric produced by weaving the quartz glass yarn of this invention in a plain weave or the like according to an ordinary method, followed by opening, and containing warp and weft threads arranged to periodically overlap. Subsequently, a surface treatment with a silane coupling agent, such as aminosilane, vinylsilane, or acrylsilane, is carried out as required.In a printed circuit board formed by impregnating a fused silica fabric with resin, microscopic examination reveals that the amount of resin at each intersection of the fabric threads is small, while the amount of resin in each mesh section (the gap between warp and weft) is large. The difference in the specific dielectric constant between the fused silica fabric and the resin is significant. Therefore, due to the relative change in the amount of resin, a microscopic dielectric constant distribution is created within the board, and this distribution causes a difference in the propagation speed of a high-frequency signal traveling through an electronic circuit formed in the upper part of the board.

[0059] To reduce the difference in the specific dielectric constant in the printed circuit board (PCB) caused by the thread stitches on the board, a so-called opening process (sometimes also referred to as a "sealing process") is carried out after the fused quartz yarns forming the quartz fabric have been woven. In this process, the quartz fibers of the warp and weft are spread out using a water jet or similar device. With sufficient opening, the filament bundles that make up each quartz yarn are adequately loosened. Viewed from above, the quartz yarn appears to expand, while the mesh size is reduced. The thickness of the quartz fabric is thus reduced.

[0060] In the present invention, the thickness of the quartz glass fabric is preferably from 8 µm to 35 µm, more preferably from 10 µm to 30 µm.

[0061] In the case of using a quartz glass yarn with a low yarn bending density, i.e., with fewer bending points resulting from yarn bending, a quartz glass fabric with fewer surface irregularities is obtained. Specifically, the mean fabric thickness measured with an electronic micrometer at a pressure of 63.2 kPa is preferably 100% to 110%, more preferably 100% to 108%, and still more preferably 100% to 105% of the mean fabric thickness measured with the electronic micrometer at a pressure of 157.9 kPa.

[0062] The thickness of the quartz glass fabric is typically measured under pressure. Therefore, irregularities on the surface of the quartz glass fabric cannot be measured. To determine the degree of irregularity, it is necessary to measure the thickness of the quartz glass fabric in its essentially unweighted state.

[0063] However, the measurement of the thickness of the quartz glass fabric varies considerably in the unweighted state, depending on whether a measurement result depends on the distal end of a measuring device being in contact with the surface of the quartz glass fabric or not, and therefore the reliability of the obtained numerical value is poor. In light of the above, in the present invention, the degree of irregularity on the surface of the quartz glass fabric was determined by performing the measurement not in the unweighted state, but at a pressure of 63.2 kPa, thus ensuring high reliability and the lowest possible pressure that can be set with the measuring device, and by comparing the result of the measurement with the result obtained when measuring at 157.9 kPa, which is normal atmospheric pressure.

[0064] The thickness of the quartz glass fabric is measured using “2) Electronic Micrometer” from “a) Deadweight Micrometer” of “7.10.1.1 Test Machine Equipment” of JIS R 3420:2013 “Testing Methods for Textile Glass Products”. Specifically, the measurement is performed with a micrometer (e.g., a Digimatic variable force micrometer of the type “Soft Touch Micro CLM2-10QBM”, manufactured by Mitutoyo Corporation) with a measuring pressure range of 63.2 kPa to 157.9 kPa. The procedure was carried out in accordance with “b) Method B” of “7.10.1.4 Operation” of JIS R 3420:2013 “Testing Methods for Textile Glass Products”, but under measuring pressures of 63.2 kPa and 157.9 kPa.

[0065] The measuring force can be varied using the variable force micrometer. Therefore, it is necessary to convert the measuring force into a measuring pressure by dividing the measuring force by the area of ​​a measuring anvil. In the case of the example Digimatic micrometer type "Soft Touch Micro CLM2-10QBM" from Mitutoyo Corporation with variable measuring force, the measuring anvil has a diameter of 6.35 mm. Therefore, the measuring pressures at a measuring force of 2 N and 5 N are 63.2 kPa and 157.9 kPa, respectively.

[0066] Additionally, as shown in “c)” of the aforementioned “7.10.1.4 Operation”, tissue thickness was measured at five points 75 mm or more apart, and an average of these measurements was defined as the thickness of the quartz glass fabric. Furthermore, the variations in these measurements were determined as standard deviations, and these variations were divided by the mean thickness to obtain a coefficient of variation. The measurement was performed at pressures of 63.2 kPa and 157.9 kPa at each measurement point.

[0067] Furthermore, the coefficient of variation of the thickness of the quartz glass fabric, measured with an electronic micrometer under a measuring pressure of 63.2 kPa, is preferably within 10%, more preferably within 7%, and even more preferably within 5%. In particular, the flatness can be made uniform over the entire quartz glass fabric by suppressing the coefficient of variation of the thickness of the quartz glass fabric.

[0068] The flatness of the quartz glass fabric is determined by the following expression (1) as an indicator of the degree of openness. [Formula 1] Flatness=TCTABS

[0069] In expression (1) T C for the thickness of the quartz glass fabric, and T ABS represents the average thickness of the quartz glass fabric, assuming that the quartz glass fabric will eventually be opened.

[0070] Fig. Figure 7 is an explanatory view illustrating the schematic representation of the flatness of the quartz glass fabric in the case where it is assumed that the quartz glass fabric will eventually be opened. Fig. Figure 7 shows quartz glass filaments 14 forming a warp quartz glass yarn, a warp quartz glass yarn 15 in a finally opened state, and a reference surface 16. The width of the reference surface is set to 1.

[0071] As used here, the state in which the quartz glass fabric is finally opened refers to a state in which the quartz glass yarns and filaments forming the fabric are completely distributed on a single plane without any constraints, and a state in which the thickness of the quartz glass fabric is extremely thin (flat). In reality, the quartz glass yarn is twisted and therefore cannot be fully opened to become flattened. Therefore, the opened state is considered merely as an indicator for quantifying flatness.

[0072] Here are, as in Fig. 7(A) shows the filaments 14 forming the warp quartz glass yarn in a finally opened state, all arranged in one plane, and therefore a width (L) can be y ) of the warp quartz glass yarn can be represented by the following expression (2). Ly=Df×Nf (In expression (2) D f for a filament diameter and N f (for the number of filaments in the quartz glass yarn).

[0073] In its finally opened state, as in Fig. As shown in Figure 7(B), the warp quartz glass threads themselves are all arranged on the reference surface, and therefore a total width L of the filaments with respect to the width of the reference surface can be represented by the following expression (3). L=Ly×Ny (In expression (3) L y for a yarn width and N y (for the number of yarns in the width of the reference area).

[0074] Therefore, as in Fig. 7(C) shows an average thickness T ave of the quartz glass fabric per width of the reference area an average value of a quartz glass filament fraction (width: L, thickness: D) f), which forms the warp quartz glass yarn, and a portion without the quartz glass filaments (width: 1-L, thickness: 0), and can therefore be represented by the following expression (4). Tave=Df×L

[0075] When expressions (2) to (4) are combined, the following expression (5) is obtained. Tave=Df×Ny×Df×Nf×Nf=Df2×Ny×Nf

[0076] Fig. 7(A) to Fig. Figure 7(C) shows a view illustrating only the warp quartz yarn, but an actual quartz fabric also contains a weft quartz yarn. The quartz yarn in the weft and the quartz yarn in the warp overlap. If an increase in fabric thickness caused by the overlap is ignored, a final quartz fabric thickness T can be calculated. ABS as the sum of a warp and a weft thread ave are considered. Therefore, the following expression (6) is used for the T ABS derived. [Formula 2] TABS=(DWf2×NWy×NWf)+(DFf2×NFy×NFf) (In expression (6) D Wf for a diameter (mm) of the quartz glass filament that forms the warp quartz glass yarn; N Wy represents the number (pieces) of warp quartz glass yarns per width of the reference surface; N Wf stands for the number (pieces) of quartz glass filaments that form the warp quartz glass yarn; DFf represents a diameter (mm) of the quartz glass filament that forms the quartz glass yarn in the weft; N Fy represents the number (pieces) of quartz glass yarns in the weft per width of the reference surface; and N Ff represents the number (pieces) of quartz glass filaments that form the quartz glass yarn in the weft.

[0077] The flatness of the quartz glass fabric is preferably 1.90 or less, more preferably 1.88 or less, and even more preferably 1.85 or less. The lower limit of the flatness of the quartz glass fabric is preferably low and is therefore 1.00. Examples

[0078] The present invention will be described in detail below with reference to examples and comparative examples, but is not limited to the following examples. [Example 1]

[0079] The raw material was a synthetic quartz glass blank with a diameter of 121 mm and a length of 2,000 mm. This blank underwent repeated circular grinding, and its roundness was measured. Finally, a quartz glass blank with a roundness of 20 µm, a diameter of 120 mm, and a length of 1,900 mm was produced.

[0080] In a cylindrical grinding step, the quartz glass block was held against both chucks of a cylindrical grinding machine and pre-ground four times with a maximum cutting depth of 0.02 mm using a grinding wheel with a #120 / 140 diamond wheel. After the rough grinding, the quartz glass block was removed from the cylindrical grinder, and a 10 mm long sample was cut from one of the ground end sections. Its roundness was measured to 60 µm using the RUNDTEST RA-2200AS manufactured by Mitutoyo Corporation.

[0081] The quartz glass blank, having undergone rough grinding, was then placed back on the cylindrical grinder and finished twice with a maximum cutting depth of 0.007 mm using a grinding wheel with a #325 / 400 diamond disc. After finishing, a sample for roundness measurement was similarly cut out, and the roundness was measured to 10 µm.

[0082] In the Fig.In the electric resistance heating oven shown in Figure 2, the resulting quartz glass block was heated and drawn to produce thick quartz glass fibers, each with a diameter of 230 µm. In this case, the outer diameter of each of the thick quartz glass fibers was measured using the laser outer diameter measuring device 44, and the insertion velocity V1 of the quartz glass block 20 into the electric resistance heating oven, as well as the winding velocity V2 of each of the thick quartz glass fibers, were subjected to feedback control. A temperature distribution in the electric resistance heating oven was achieved by using the four [missing information - likely a specific measurement device]. Fig. The gas inlet tubes 48 shown as inlet openings for nitrogen, which was a protective gas for the electric resistance heating furnace, were minimized, and the local variation of the outer diameter of the thick quartz glass fiber was suppressed.

[0083] Next, as in Fig.Figure 3 shows 70 thick quartz glass fibers 43 being introduced simultaneously into the flame, which was generated by 70 wide, parallel burners B1 with a wide hydrogen-oxygen flame. The feed rate was controlled by adjusting the rotational speed of the feed roller 53. Simultaneously, the thick quartz glass fibers 43 were wound onto the winder 49, while, from the opposite direction of the burners, they were bundled by the sizing applicator 50 and the condenser 47. This resulted in a quartz glass strand comprising 70 filaments, each with a diameter of 3.7 µm.

[0084] The resulting quartz glass strand was twisted into quartz glass yarn on a twisting machine with 16 twists / m.

[0085] Furthermore, by using the quartz glass yarn, a smooth woven quartz glass fabric was produced with a weave density of 95 warp threads / inch (3.74 warp threads / mm) and 95 weft threads / inch (3.74 weft threads / mm), a width of 1 m and a length of 1,000 m.

[0086] The quartz glass fabric was then subjected to an opening process using a high-pressure water jet, in which a large number of small-diameter rotary nozzles, each with a diameter of 0.1 mm to 0.2 mm, were arranged at equal intervals in the width direction of the quartz glass fabric.

[0087] Afterwards, the quartz glass fabric, which had undergone the opening process, was subjected to a surface treatment with an aminosilane surface treatment agent using a vertical applicator.

[0088] In Example 1, two trials were carried out in twisting (spinning) and in the manufacture of the quartz glass fabric from the obtained quartz glass yarn, and the resulting quartz glass yarns were considered as quartz glass yarns of Examples 1-1 and 1-2, and the resulting quartz glass fabrics as quartz glass fabrics of Examples 1-1 and 1-2. 1. Evaluation of the quartz glass yarn

[0089] Regarding the obtained quartz glass yarn, the yarn bending density, tensile strength, and initial fracture strength were measured using the previously mentioned methods. The results for yarn bending are shown in Table 1, and the results for tensile strength and initial fracture strength are shown in Table 2. 2. Evaluation of the quartz glass fabric

[0090] Regarding the obtained quartz glass fabric, the fabric thickness was measured using the aforementioned method, and an average value was calculated. Specifically, the fabric thickness was measured at five points 75 mm or more apart using the Digimatic micrometer "Soft Touch Micro CLM2-10QBM" of the variable force type, manufactured by Mitutoyo Corporation, at pressures of 63.2 kPa and 157.9 kPa. A mean value at the five points, a coefficient of variation thereof, and a ratio of the mean fabric thickness measured at 63.2 kPa to the mean fabric thickness measured at 157.9 kPa were calculated. The results are presented in Table 3.

[0091] Furthermore, the surface smoothness of the resulting quartz glass fabric was evaluated using the following methods, specifically the flatness, gloss, and linting. The results are shown in Table 4.

[0092] The evaluation was carried out as described below. Each of the quartz glass fabrics from the examples and comparison samples was pulled out on a roll and placed on a flat table. The quartz glass fabric was then visually evaluated by shining a light source with a luminance of 10,000 lux obliquely from above. <flachheit>

[0093] The flatness was quantified using the following expression (1) as an indicator of the degree of openness. [Formula 3] Flatness=TCTABS

[0094] In expression (1) T C for the thickness of the quartz glass fabric, and T ABS represents the average thickness of the quartz glass fabric, assuming that the quartz glass fabric will eventually be opened.

[0095] T ABS was calculated by replacing each parameter of the quartz glass fabric with the following expression (6) described above. [Formula 4] TABS=(DWf2×NWy×NWf)+(DFf2×NFy×NFf)

[0096] For each of the examples and comparison examples, the final thickness of the quartz glass fabric T was determined. ABS calculated using expression (6) as described below. T ABS Example 1 and comparison example 1 = 0.0072 (mm) T ABS Example 2 and comparison example 2 = 0.0148 (mm)

[0097] The results of the calculated flatness of the quartz glass fabric using the previously mentioned values ​​are shown in Table 4. Additionally, the flatness was evaluated as follows: a flatness of 1.90 or less was represented by the symbol "o"; a flatness of 1.91 to 2.00 was represented by the symbol "Δ"; and a flatness of 2.01 or more was represented by the symbol "×". <glanzton>

[0098] The gloss tone was evaluated taking advantage of the fact that the gloss tone varies depending on the waviness and yarn bends on the surface of the quartz glass fabric as follows: A case in which no change in gloss tone was observed was represented by the symbol “o”; a case in which a slight change in gloss tone was observed was represented by the symbol “Δ”; and a case in which a significant change in gloss tone was observed was represented by the symbol “×”. <flussel>

[0099] The lint was assessed as follows: a case of 10 pieces / m2 or less was represented by the symbol “◯”; a case of 11 pieces / m2 or more and 20 pieces / m2 or less was represented by the symbol “Δ”; and a case of 21 pieces / m2 or more was represented by the symbol “×”. [Example 2]

[0100] A quartz glass strand was produced using the same procedure as in Example 1, except that the filament diameter was changed from 3.7 µm to 5.3 µm and the number of filaments from 70 to 100, and then a quartz glass yarn was produced by twisting the quartz glass strand with 12 twists / m.

[0101] Furthermore, a smooth-woven quartz glass fabric with a weave density of 66 warp threads / inch (2.60 warp threads / mm) and 68 weft threads / inch (2.68 weft threads / mm) was produced using the quartz glass yarn mentioned above, following the same procedure as in Example 1. The single-sided woven quartz glass fabric was then subjected to the opening procedure under the same opening conditions as in Example 1.

[0102] In Example 2, two trials were carried out in spinning and in the manufacture of the quartz glass fabric from the obtained quartz glass yarn, and the resulting quartz glass yarns were considered as quartz glass yarns of Examples 2-1 and 2-2, and the resulting quartz glass fabrics as quartz glass fabrics of Examples 2-1 and 2-2.

[0103] The resulting quartz glass yarns and quartz glass cloths were evaluated using the same methods as in Example 1. The results are presented in Tables 1 to 4. 3. Evaluation of the printed circuit board

[0104] A microstrip circuit board was formed using the obtained quartz glass fabric, and the stability of a characteristic impedance was evaluated.

[0105] The printed circuit board thickness is preferably 100 µm or more to measure a characteristic impedance through a microstrip line. Therefore, a printed circuit board for measuring the characteristic impedance was fabricated and evaluated using two layers of the quartz glass fabrics from Example 2-1 and Comparative Example 2-1, each with a fabric thickness of approximately 30 µm.

[0106] A cross-sectional view of the wave impedance measuring plate is shown in Fig. 8 shown. Fig. Figure 8 shows a conductor 100, a mass 102, a quartz glass fabric 103 and a prepreg 104.

[0107] The resulting quartz glass fabric 103 was impregnated with an epoxy resin containing 50 wt% of a quartz glass filler to produce the prepreg 104 formed from the quartz glass fabric 103 and the epoxy resin. The ratio of the quartz glass fabric 103 to the epoxy resin in the resulting prepreg 104 was 40 wt% and 60 wt%, respectively.

[0108] Two layers of prepreg 104 were stacked and further heated and, together with copper foils stacked on their two outer surfaces, subjected to pressure to produce a double-sided copper-clad laminate (double-sided CCL) which was used as a measuring plate for the characteristic impedance.

[0109] The thickness of the measuring plate for the characteristic impedance was 100 µm, and the line 100 to be evaluated was a microstrip line formed on both surfaces of the measuring plate for the characteristic impedance, having a line width of 100 µm and a line length of 30 mm.

[0110] A characteristic impedance Z was measured using the TDR54754A manufactured by Agilent Technologies, Inc., and any difference between the maximum and minimum values ​​of this impedance was evaluated as fluctuation.

[0111] The start time of a TDR pulse was set to 20 ps, ​​and the measurement was performed three times. The values ​​at both ends of the data were discarded. Subsequently, the difference (maximum value - minimum value) of the mean values ​​of the characteristic impedances Z at the respective TDR times (53.4 ns to 54.4 ns) was defined as the fluctuation of the characteristic impedance Z.

[0112] The wave impedance was evaluated as follows: A case in which the wave impedance fluctuation Z was less than 2% of the wave impedance Z was represented by the symbol “◯”; and a case in which the wave impedance fluctuation Z was equal to or greater than 2% was represented by the symbol “×”. The evaluation results are shown in Table 5. [Comparison example 1]

[0113] A thick quartz glass fiber with a diameter of 230 µm was produced according to the same procedure as in Example 1, except that the quartz glass block used as raw material was not subjected to circular grinding, and then a quartz glass strand consisting of 70 quartz glass filaments, each with a quartz glass filament diameter of 3.7 µm, was produced according to the same procedure as in Example 1, and then a quartz glass yarn was produced by twisting the quartz glass strand with 16 twists / m.

[0114] Furthermore, a smooth woven quartz glass fabric with a weave density of 95 warp threads / inch (3.74 warp threads / mm) and 95 weft threads / inch (3.74 weft threads / mm), a width of 1 m and a length of 1,000 m was produced using the aforementioned quartz glass yarn according to the same procedure as in Example 1. The smooth woven quartz glass fabric was then subjected to the opening procedure under the same opening conditions as in Example 1.

[0115] In comparative example 1, two trials were carried out in spinning and in the production of the quartz glass fabric from the obtained quartz glass yarn, whereby the resulting quartz glass yarns were considered as quartz glass yarns of comparative examples 1-1 and 1-2 and the resulting quartz glass fabrics as quartz glass fabrics of comparative examples 1-1 and 1-2.

[0116] The resulting quartz glass yarns and quartz glass cloths were evaluated using the same methods as in Example 1. The results are presented in Tables 1 to 4. [Comparative example 2]

[0117] A thick quartz glass fiber with a diameter of 230 µm was produced according to the same procedure as in Example 1, except that the quartz glass block used as raw material was not subjected to circular grinding, and then a quartz glass strand of 100 quartz glass filaments, each with a quartz glass filament diameter of 5.3 µm, was produced according to the same procedure as in Example 2 for the other conditions, and then a quartz glass yarn with 12 twists / m was produced by twisting the quartz glass strand.

[0118] Furthermore, a smooth woven quartz glass fabric with a weave density of 66 warp threads / inch (2.60 warp threads / mm) and 68 weft threads / inch (2.68 weft threads / mm) was produced using the quartz glass yarn mentioned above, according to the same procedure as in Example 1. The single-sided woven quartz glass fabric was then subjected to the opening procedure under the same opening conditions as in Example 1.

[0119] In comparative example 2, two trials were carried out in spinning and in the production of the quartz glass fabric from the obtained quartz glass yarn, whereby the resulting quartz glass yarns were considered as quartz glass yarns of comparative examples 2-1 and 2-2 and the resulting quartz glass fabrics as quartz glass fabrics of comparative examples 2-1 and 2-2.

[0120] The resulting quartz glass yarns and quartz glass cloths were evaluated using the same methods as in Example 1. The results are presented in Tables 1 to 4.

[0121] Furthermore, the quartz glass fabric of Comparative Example 2-1 was impregnated with an epoxy resin containing 50 wt% of a quartz glass filler to produce a prepreg formed from the quartz glass fabric and the epoxy resin. The ratio of the quartz glass fabric to the epoxy resin in the resulting prepreg was 40 wt% and 60 wt%, respectively.

[0122] Two layers of the prepreg were stacked and further heated, and then pressurized together with copper foils stacked on both outer surfaces of the prepreg to produce a double-sided copper-clad laminate (CCL). The double-sided copper-clad laminate was evaluated in the same manner as in Example 2-1. The results are shown in Table 5. [Table 1] Results of silicon glass fiber Example 1-1 Example 1-2 Example 2-1 Example 2-2 Comparison example 1-1 Comparison example 1-2 Comparative example 2-1 Comparative example 2-2 Number of fiber bends (piece(s) / fiber) 3 4 1 0 10 9 6 7 Fiber bending density (piece(s) / cm) 0,075 0,100 0,025 0,000 0,250 0,225 0,150 0,175 [Table 2] Results of the quartz glass fiber Tensile strength (GPa) Initial breaking strength (GPa) Initial breaking strength / tensile strength (%) Example 1-1 3,37 3,37 100,0 Example 1-2 3,51 3,11 89,6 Example 2-1 2,41 2,28 94,6 Example 2-2 2,51 2,14 86,6 Comparison example 1-1 3,36 3,01 88,6 Comparison example 1-2 3,59 3,25 90,5 Comparative example 2-1 2,37 2,17 91,6 Comparative example 2-2 2,54 2,20 85,3 [Table 3] Results of the quartz glass fabric Average tissue thickness 63.2 kPa / 157.9 kPa (%) Thickness variation coefficient Below 63.2 kPa(mm) Below 157.9 kPa(mm) Below 63.2 kPa (%) Below 157.9 kPa (%) Example 1-1 0,0142 0,0136 104 4 3 Example 1-2 0,0147 0,0137 107 6 4 Example 2-1 0,0292 0,0278 105 4 2 Example 2-2 0,0282 0,0272 104 2 1 Comparison example 1-1 0,0169 0,0143 118 16 12 Comparison example 1-2 0,0178 0,0146 122 18 15 Comparative example 2-1 0,0345 0,0284 121 20 17 Comparative example 2-2 0,0342 0,0286 120 18 13 [Table 4] Results of the quartz glass fabric Flatness Gloss tone lint Comprehensive assessment Example 1-1 1,90 ◯ ◯ ◯ ◯ Example 1-2 1,90 ◯ ◯ ◯ ◯ Example 2-1 1,87 ◯ ◯ ◯ ◯ Example 2-2 1,83 ◯ ◯ ◯ ◯ Comparison example 1-1 1,98 △ ◯ △ × Comparison example 1-2 2,02 × ◯ △ × Comparative example 2-1 1,92 △ △ × × Comparative example 2-2 1,93 △ ◯ △ × [Table 5] Results of the quartz glass fabric Z FluctuationZ Range of variation (%) Evaluation Example 2-1 50 Ω 0.9 Ω 1,8 ◯ Comparative example 2-1 53 Ω 1.8 Ω 3,4 ×

[0123] As can be seen from Tables 1 to 5, the quartz glass fabrics of Examples 1 and 2, each produced from the quartz glass yarns with fewer bending points attributable to yarn bending, exhibited excellent flatness, no variation in luster and suppressed linting, and were also excellent in the stability of a characteristic impedance. Reference symbol list

[0124] 10: Quartz glass yarn, 12: Bending point of quartz glass yarn, 13: Curved section that is not a bending point, 14: Quartz glass filament, 15: Warp quartz glass yarn in the final open state, 16: Reference surface, 18: Quartz glass strand, 20: Quartz glass block, 42: Electric resistance heating oven, 43: Thick quartz glass fiber, 44: Laser outside diameter gauge, 46: Core tube, 47: Capacitor, 48: Gas inlet tube, 49: Winder, 50: Coating applicator, 53: Feed roller, 61: Winding speed controller, 62: Block feed speed controller, 100: Conduit, 102: Bottom, 103: Quartz glass fabric, 104: Prepreg, B1: Wide hydrogen-oxygen flame burner, F1: Burner flame, M: high-precision winding machine, r: radius of curvature, V1: insertion speed of the quartz glass block, V2: winding speed of the thick quartz glass fiber, θ: bending angle.< / flussel> < / glanzton> < / flachheit>

Claims

[1] Quartz glass yarn having a yarn bending density of 0.10 pieces / cm or less, determined by the number of yarn bends of the quartz glass yarn per unit length of the quartz glass yarn, wherein the yarn bends each have a bending point with a radius of curvature of 5 mm or less and a bending angle of 120° or less, wherein quartz glass filaments form the quartz glass yarn and are obtained by spinning a quartz glass block with a diameter of 100 to 200 mm and a roundness of 50 µm or less, wherein the roundness is defined by a difference between the radii of two concentric geometric circles, when a circular cross-section of the quartz glass block lies between the two concentric geometric circles and the distance between the two concentric geometric circles is minimal, wherein the quartz glass filaments each have a filament diameter of 3.0 µm to 10.0 µm, wherein the number of quartz glass filaments is from 20 to 300, and where the number of twists of the quartz glass yarn ranges from 4 twists / m to 24 twists / m. [2] Quartz glass yarn according to claim 1, wherein the quartz glass yarn has a tensile strength of 2.0 GPa or more, and wherein the quartz glass filaments forming the quartz glass yarn each have an initial breaking strength of 80.0% or more of the tensile strength of the quartz glass yarn. [3] Quartz glass fabric obtained by weaving and opening using the quartz glass yarn according to claim 1 or 2. [4] Quartz glass fabric according to claim 3, wherein the quartz glass fabric has a mean value of a fabric thickness measured with an electronic micrometer under a measuring pressure of 63.2 kPa, of 100% to 110% of a mean value of a fabric thickness measured with the electronic micrometer under a measuring pressure of 157.9 kPa. [5] Quartz glass fabric according to claim 3 or 4, wherein the quartz glass fabric has a coefficient of variation of a fabric thickness, measured with an electronic micrometer under a measuring pressure of 63.2 kPa, within 10%. [6] Quartz glass fabric obtained by weaving and opening using a quartz glass yarn formed from quartz glass filaments, having a bending density of 0.10 pieces / cm or less as determined by the number of yarn bends of the quartz glass yarn per unit length of the quartz glass yarn, wherein each yarn bend has a bend point having a radius of curvature of 5 mm or less and a bend angle of 120° or less, wherein the quartz glass filaments are obtained by spinning a quartz glass block with a diameter of 100 to 200 mm and a roundness of 50 µm or less, wherein the roundness is defined by a difference between the radii of two concentric geometric circles, when a circular cross-section of the quartz glass block lies between the two concentric geometric circles and the distance between the two concentric geometric circles is minimal, wherein the quartz glass fabric has a mean fabric thickness measured with an electronic micrometer under a measuring pressure of 63.2 kPa of 100% to 110% of a mean fabric thickness measured with the electronic micrometer under a measuring pressure of 157.9 kPa. [7] Quartz glass fabric obtained by weaving and opening using a quartz glass yarn formed from quartz glass filaments, having a bending density of 0.10 pieces / cm or less, determined by the number of yarn bends of the quartz glass yarn per unit length of the quartz glass yarn, each having a bend point with a radius of curvature of 5 mm or less and a bend angle of 120° or less, wherein the quartz glass filaments are obtained by spinning a quartz glass block with a diameter of 100 to 200 mm and a roundness of 50 µm or less, wherein the roundness is defined by a difference between the radii of two concentric geometric circles, when a circular cross-section of the quartz glass block lies between the two concentric geometric circles and the distance between the two concentric geometric circles is minimal, where the quartz glass fabric has a coefficient of variation of a fabric thickness, measured with an electronic micrometer under a measuring pressure of 63.2 kPa, within 10%.

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