Glass yarn, glass cloth, and method for manufacturing glass yarn

Abstract

The present invention provides a glass yarn in which multiple glass filaments are bundled together, wherein the glass material constituting the glass filaments contains 40-60% by mass of SiO2 and 15-35% by mass of B2O3, and the average fiber diameter of the glass filaments is 3-6 μm, and which can suppress the generation of fluff when made into glass cloth. [Solution] A glass yarn comprising a bundle of multiple glass filaments, wherein the glass material constituting the glass filaments contains 40-60% by mass of SiO2 and 15-35% by mass of B2O3, the number of glass filaments is 30-120, the average fiber diameter of the glass filaments is 3-6 μm, the count of the glass yarn is 0.3-6 tex, and the Worcester spot of the glass yarn is 0.5-2.0%.

Description

[Technical Field]

[0001] The present invention relates to glass yarn, glass cloth woven using the glass yarn as warp and / or weft, and a method for manufacturing the glass yarn. [Background technology]

[0002] Glass yarn is made by bundling together numerous glass filaments to form a thread. Due to its excellent properties such as electrical insulation, dimensional stability, heat resistance, chemical resistance, and tensile strength, glass yarn is used as a raw material for glass cloth, glass tape, glass sleeves, and rubber reinforcement cords.

[0003] One application of glass cloth is in printed circuit boards (PCBs), where the quality of the PCB significantly impacts its performance. As the glass cloth used in PCBs becomes thinner, the raw material, glass yarn, is also being made lower in count (e.g., around 0.3-6 tex). Furthermore, due to the rapidly increasing demand for high-speed transmission of large amounts of data, glass yarn used in PCBs requires a lower dielectric constant. Examples of glass fibers composed of low-dielectric-constant glass materials are disclosed in Patent Documents 1-5. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 62-226839 [Patent Document 2] Special Publication No. 2010-508226 [Patent Document 3] Japanese Patent Publication No. 2009-286686 [Patent Document 4] International Publication No. 2017 / 187471 Pamphlet [Patent Document 5] International Publication No. 2018 / 216637 brochure [Overview of the Initiative]

Problems to be Solved by the Invention

[0005] Generally, as methods for manufacturing glass filaments, there are two types: the direct method and the indirect method. The direct method (direct melt method) is a method in which a bushing is attached to the bottom of a working tank provided at the tip of a glass melting furnace, and molten glass is directly introduced and spun. On the other hand, the indirect method (marble melt method) is a method in which glass melted in a glass melting furnace is first formed into a glass raw material having a predetermined shape such as a glass ball, rod, flake, or scale shape with a diameter of about 10 to 30 mm called a marble, and this glass raw material is put into a bushing and remelted and spun.

[0006] Here, when using a low dielectric constant glass material containing 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3 to obtain a glass filament with a fine fiber diameter of about 3 to 6 μm, it is necessary to set the melting temperature of the molten glass at a higher temperature compared to E glass or the like. And the present inventors have found that when increasing the melting temperature of the glass material with a high content of B2O3 as described above, bubbles are likely to generate in the molten glass. Furthermore, the present inventors have found that when spinning with the molten glass containing bubbles, a part inside the spun glass filament called a hollow fiber becomes hollow. Hollow fibers not only affect the strength of the glass filament but also cause a decrease in the insulation reliability of the printed wiring board.

[0007] And the present inventors have found that when using a low dielectric constant glass material containing 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3 to obtain a glass filament with a fine fiber diameter of about 3 to 6 μm, it is effective to perform the process by the indirect method rather than the direct method in order to reduce hollow fibers. Specifically, in the direct method, since the molten glass melted in the glass melting furnace is directly spun, it is difficult to sufficiently clarify the molten glass, whereas in the indirect method, it has been found that the generation of bubbles can be suppressed by performing clarification in two stages: when manufacturing the glass raw material and when spinning using this glass raw material.

[0008] When the inventors studied, in the indirect method, when manufacturing glass filaments with a fine fiber diameter of about 3 to 6 μm composed of a low dielectric constant glass material containing 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3, the generation of hollow fibers was reduced. However, there is still room for improvement in the generation of flyers of the glass cloth containing the glass filaments.

[0009] Therefore, the main object of the present invention is to solve the above problems and provide a glass yarn in which a plurality of glass filaments are bundled, and the glass material constituting the glass filaments contains 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3, and the average fiber diameter of the glass filaments is 3 to 6 μm, and to suppress the generation of flyers when making a glass cloth.

Means for Solving the Problems

[0010] When the inventors studied the cause of the above problems, it was found that the generation of flyers is greatly related to the mass variation in the length direction of the glass yarn. Specifically, it was found that in a glass yarn with a large mass variation in the length direction, there are portions where the filament diameter is thin and thick in the length direction of the glass filaments. And, due to the friction with members in the warping process during the production of glass cloth and weaving using an air jet loom, the thin portion of the filament diameter is likely to break, and combined with the fact that glass filaments composed of a glass material containing 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3 are inferior in mechanical strength compared to E glass etc., it was found that flyers are likely to occur.

[0011] And, when the inventors studied intensively, during the spinning of glass filaments by the indirect method, the temperature (T of the region where the glass raw material in the bushing is not completely melted and exists in a solid state (hereinafter, may be referred to as the "region where solid glass raw material exists" in this specification). in) and the temperature (T) near the nozzle plate where the glass filament is spun. out ) difference ((T out )-(T in By spinning the yarn at a specific temperature range, it was possible to create a glass yarn with a fine fiber diameter of approximately 3-6 μm, composed of a low dielectric constant glass material containing 40-60% by mass of SiO2 and 15-35% by mass of B2O3. This glass yarn, which is an indicator of longitudinal mass variation, can be made to a specific range. It was discovered that glass yarn with this specific range of Worcester spots can suppress the generation of fluff when made into glass cloth.

[0012] In other words, the present invention provides inventions in the following embodiments. Item 1. A glass yarn comprising a bundle of multiple glass filaments, wherein the glass material constituting the glass filaments contains 40-60% by mass of SiO2 and 15-35% by mass of B2O3, the number of glass filaments is 30-120, the average fiber diameter of the glass filaments is 3-6 μm, the count of the glass yarn is 0.3-6 tex, and the Worcester spot of the glass yarn is 0.5-2.0%. Item 2. The glass yarn described in Item 1, wherein the number of twists of the glass yarn is 0.3 to 1.2 times / 25 mm. Item 3. A glass cloth woven using the glass yarn described in Item 1 or 2 as warp and / or weft. Item 4. A method for manufacturing a glass yarn according to item 1 or 2, comprising the step of manufacturing a glass filament using a bushing comprising a melting section for melting introduced glass raw materials to produce molten glass, a nozzle plate provided below the melting section, and a heating means for heating the melting section and the nozzle plate, wherein the melting section includes a region in which the glass raw materials are not completely melted and remain solid, and a region in which the glass raw materials are completely melted and no solid glass raw materials exist, and the temperature T of the region in which the glass raw materials are not completely melted and remain solid in and the temperature T near the nozzle plate out The difference (T out -Tin A method for manufacturing glass yarn according to item 1 or 2, wherein the glass filament is manufactured at a temperature of 10 to 200°C. [Effects of the Invention]

[0013] According to the present invention, a glass yarn is formed by bundling together a plurality of glass filaments, wherein the glass material constituting the glass filaments contains 40-60% by mass of SiO2 and 15-35% by mass of B2O3, the number of glass filaments is 30-120, the average fiber diameter of the glass filaments is 3-6 μm, the count of the glass yarn is 0.3-6 tex, and the Worcester spot of the glass yarn is 0.5-2.0%, thereby suppressing the generation of fluff when the glass yarn is made into a glass cloth. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic side view showing an example of a glass filament bundle manufacturing apparatus for producing glass strands (glass filament bundles) that will be used as glass yarn according to the present invention. [Figure 2] Figure 1 is a top view of the glass filament bundle manufacturing apparatus. [Figure 3] This is a schematic plan view of the partition member from above. [Figure 4] This is a plan view of the nozzle plate. [Figure 5] This is a cross-sectional view of the nozzle. [Figure 6] This is a side view of the bushing. [Modes for carrying out the invention]

[0015] The glass yarn of the present invention is a glass yarn formed by bundling together a plurality of glass filaments, wherein the glass material constituting the glass filaments contains 40-60% by mass of SiO2 and 15-35% by mass of B2O3, the number of glass filaments is 30-120, the average fiber diameter of the glass filaments is 3-6 μm, the count of the glass yarn is 0.3-6 tex, and the Worcester spot of the glass yarn is 0.5-2.0%. The glass yarn of the present invention will be described in detail below.

[0016] <Glass materials> The glass yarn of the present invention is made up of multiple glass filaments bundled together, and the glass filaments are composed of a glass material containing 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3.

[0017] (SiO2) In the glass material constituting glass filaments, SiO2 is an essential component for forming the glass network structure. SiO2 has the effect of lowering the dielectric constant, and by setting the SiO2 content to 40% or more, a glass yarn with a low dielectric constant can be made. On the other hand, by setting the content to 60% or less, the viscosity of the molten glass can be made appropriate, making it easier to create a homogeneous glass composition when spinning glass filaments. From these viewpoints, the SiO2 content is preferably 45 to 55% by mass, more preferably 45 to 53% by mass, and even more preferably 45 to 49% by mass.

[0018] (B2O3) B2O3 is an essential component for forming the network structure of glass. B2O3 has the effect of lowering the dielectric constant, reducing the viscosity of molten glass, improving degassing (bubble removal), and suppressing the incorporation of air bubbles into the formed glass filament. By setting the B2O3 content to 15% or more, it is possible to produce glass yarn with a low dielectric constant, and by lowering the viscosity of the molten glass during glass melting, it is possible to obtain glass filaments with an average fiber diameter of 3 to 6 μm. On the other hand, by setting the content to 35% by mass or less, it becomes easier to obtain a homogeneous glass composition when spinning glass filaments. From these viewpoints, the B2O3 content is preferably 15 to 30% by mass, more preferably 20 to 30% by mass, and even more preferably 25 to 30% by mass.

[0019] (SiO2 / B2O3) From the viewpoint of lowering the dielectric constant of the glass yarn, preventing the inclusion of air bubbles in the glass filament, and improving the homogeneity of the glass composition in the glass filament, the ratio of SiO2 to B2O3 (SiO2 / B2O3) is preferably 1.5 to 1.9, and more preferably 1.7 to 1.8.

[0020] The amount of glass composition other than SiO2 and B2O3 can be 5 to 40% by mass, preferably 10 to 32% by mass, and more preferably 16 to 30% by mass.

[0021] (Al2O3) Al2O3 is a component that forms the network structure of glass. Al2O3 has the effect of increasing the chemical durability of the glass composition. On the other hand, Al2O3 makes the glass composition more susceptible to devitrification during spinning. The Al2O3 content is preferably 5 to 18% by mass, more preferably 8 to 18% by mass, and even more preferably 12 to 16% by mass.

[0022] Examples of glass composition other than SiO2, B2O3, and Al2O3 include 0 to 32% by mass, preferably 0 to 10% by mass, and more preferably 5 to 10% by mass.

[0023] (MgO) MgO is an optional component that reduces the viscosity of the glass composition during melting, suppresses the incorporation of bubbles into the glass fibers, and improves the homogeneity of the glass composition. The MgO content is 0 to 10% by mass, preferably 1 to 8% by mass, and more preferably 1 to 6% by mass.

[0024] (CaO) CaO is an optional component that improves the solubility of glass raw materials and reduces the viscosity of the glass composition during melting, but it has a significant effect of increasing the dielectric constant of the glass composition. Therefore, the CaO content is preferably 0 to 10% by mass, more preferably 3 to 8% by mass, and more preferably 4 to 7% by mass.

[0025] (Li2O) Li2O is an optional component that, even in small amounts, reduces the viscosity of the glass composition during melting, suppressing the incorporation of bubbles into the glass fibers, and also suppresses devitrification. Although its effect is relatively weaker than that of other alkali metal oxides, Li2O increases the dielectric constant of the glass composition. The Li2O content is preferably 1.5% by mass or less, 1% by mass or less, or 0.5% by mass or less.

[0026] (Fe2O3) Fe2O3 is an optional component that improves the solubility of glass raw materials through its heat-absorbing properties, as well as improving the homogeneity of the glass composition during melting. Due to the homogeneity-improving effect of Fe2O3, even when the fiber diameter of the formed glass fibers is small, the occurrence of fiber breakage during spinning is suppressed, improving spinning operability. The Fe2O3 content is 0.01 to 0.50% by mass, particularly preferably 0.05 to 0.30% by mass.

[0027] Furthermore, the glass filament may contain glass compositions other than those listed above, as a glass composition other than SiO2 and B2O3. For example, other components that the glass composition may contain include Na2O, P2O5, K2O, SrO, BaO, PbO, TiO2, ZrO2, La2O3, Y2O3, MoO3, WO3, Nb2O5, Cr2O3, SnO2, CeO2, As2O3, Sb2O3, and SO3. Other components that the glass composition may contain include, for example, noble metal elements such as Pt, Rh, Os, and Ir, and halogen elements such as F and Cl.

[0028] (Glass yarn) The glass yarn of the present invention is formed by bundling together glass filaments made of the aforementioned glass material.

[0029] The glass yarn of the present invention has 30 to 120 glass filaments. By setting the number of filaments within this range, it is possible to create a thin glass cloth while suppressing the generation of fluff. From the viewpoint of making it easier to obtain an even thinner glass cloth, 30 to 60 filaments is preferred.

[0030] The glass yarn of the present invention has an average fiber diameter of 3 to 6 μm. By keeping it within this range, it is possible to create a thin glass cloth while suppressing the generation of fluff. The above average fiber diameter is determined by embedding the glass yarn in epoxy resin (product name 3091, manufactured by Marumoto Storuas Co., Ltd.) so that its cross-section can be observed, curing it, polishing it so that it can be observed, observing it with a SEM (product name JSM-6390A, manufactured by JEOL Ltd.) at a magnification of 1000x, measuring the diameter of all glass filaments constituting the glass yarn (the largest part), calculating the average value, and taking this average value as the average fiber diameter of the glass filaments.

[0031] The glass yarn of the present invention has a count of 0.3 to 6 tex. By setting the range in this way, while making a thin glass cloth, it becomes easier to suppress the generation of fly. The count of the glass yarn is measured in accordance with the method specified in "7.1 Count" of "General Test Methods for Glass Fibers" of JIS R 3420 2013.

[0032] The glass yarn of the present invention has a Uster unevenness of 0.5 to 2.0%. As described above, according to the studies by the present inventors, it has been found that the generation of fly is closely related to the mass variation in the length direction of the glass yarn. Specifically, it has been found that in a glass yarn with a large mass variation in the length direction, there are thin and thick portions in the filament diameter in the length direction of the glass filament. And, due to the friction with members in the warping process during the production of glass cloth and the weaving using an air jet loom, the thin portion of the filament diameter is likely to break, and also, combined with the fact that a glass filament composed of a glass material containing 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3 is inferior in mechanical strength compared to a glass filament made of E glass, etc., it has been found that fly is likely to occur.

[0033] And, as a result of intensive studies by the present inventors, during the indirect method of glass filament spinning, the temperature (T in ) of the solid glass raw material existing region of the bushing and the temperature (T out ) near the nozzle plate from which the glass filament is spun out, the difference ((T out ) - (T in )) is controlled to be within a specific temperature range for spinning, so that when using a glass yarn with a fine fiber diameter of about 3 to 6 μm composed of a low dielectric constant glass material containing 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3, the Uster unevenness, which is an index of the longitudinal mass variation, can be within a specific range, and it has been found that a glass yarn with the Uster unevenness within the specific range can suppress the generation of fly when made into a glass cloth.

[0034] From the viewpoint of achieving a better balance between improving spinning performance and further suppressing the generation of fluff, the Worcester flecks in the glass yarn of the present invention are preferably 0.5 to 1.4%, and more preferably 0.8 to 1.2%.

[0035] In this invention, the Worcester flecks of glass yarn are measured using a Worcester tester model 4-CX-R1.7 manufactured by Zerbeger Worcester GmbH under the following measurement conditions (U%). (Measurement conditions) Measurement mode: Normal Yarn feeding speed: 200m / min Measured thread length: 500m Twister: Z-twist, 12,000 turns / min Disc tension strength: 10%

[0036] In the glass yarn of the present invention, the number of hollow fibers in the multiple glass filaments constituting the glass yarn is preferably one or less per 10,000 glass filaments, and more preferably zero. The number of hollow fibers is measured by measuring the length of the glass filament at 1 cm per location, and this is measured at any 10,000 locations. For example, when measuring the number of hollow fibers in a glass yarn with 50 filaments, a measurement sample is cut from the glass yarn at any 200 locations, each measuring 1 cm. By observing the number of hollow fibers per 1 cm of glass filament at these 200 locations, the number of hollow fibers per 1 cm at 50 × 200 = 10,000 locations can be observed. Hollow fibers can be observed by cutting a piece of glass yarn to be observed to about 1 cm, immersing it in a liquid with a refractive index similar to that of glass filaments (e.g., benzyl alcohol), loosening the glass filaments in the yarn so that each one can be observed side by side, shining a light source such as an LED from above, and observing them with an optical microscope at a magnification of 5 to 10 times. In other words, observation can be made by utilizing the difference between the refractive index of the part where hollow fibers are generated (the hollow part) and the refractive index of the glass and the above-mentioned liquid.

[0037] The glass yarn of the present invention preferably has a twist count of 0.3 to 1.2 turns / 25 mm. In particular, when the number of glass filaments in the glass yarn is relatively small, at 30 to 60 strands, a twist count of 0.5 to 1.1 turns / 25 mm is more preferable, 0.7 to 1.1 turns / 25 mm is even more preferable, and 0.9 to 1.1 turns / 25 mm is particularly preferable, from the viewpoint of further suppressing the generation of fluff. In the present invention, the twist count is measured in accordance with JIS R 3420:2013 7.5.

[0038] <glass cloth> The glass cloth of the present invention is preferably woven using the glass yarn of the present invention as warp and / or weft threads, and more preferably woven using the glass yarn of the present invention as both warp and weft threads.

[0039] The thickness of the glass cloth of the present invention is not particularly limited, but for example, it can be 8 to 30 μm. The mass of the glass cloth of the present invention is also not particularly limited, but for example, it can be 6 to 30 g / m². 2 These are some examples.

[0040] The hollow fibers in the glass cloth of the present invention preferably amount to one or less per 10,000 glass filaments constituting the glass cloth, and more preferably zero. The number of hollow fibers is determined by cutting a 10cm x 10cm square sample from the glass cloth and measuring the glass filament length of 1cm at each location, and this measurement is taken at any 10,000 locations in the sample.

[0041] <Method for manufacturing glass yarn> The present invention provides a method for manufacturing glass yarn, which includes a step of manufacturing a glass filament using a bushing comprising: a melting section that melts the introduced glass raw material to produce molten glass; a nozzle plate provided below the melting section; and a heating means for heating the melting section and the nozzle plate, wherein the melting section includes a region in which the glass raw material is not completely melted and remains solid, and a region in which the glass raw material is completely melted and no solid glass raw material remains, and the temperature T of the region in which the glass raw material is not completely melted and remains solid in and the temperature T near the nozzle plate out The difference (T out -T in The main feature of this invention is that it manufactures glass filaments at a temperature of 10 to 200°C. The manufacturing method of the glass yarn of the present invention will be described in detail below. First, an overview of the glass filament bundle manufacturing apparatus for manufacturing glass strands (glass filament bundles) to be used as the glass yarn of the present invention will be described, and then the main features of the manufacturing method of the glass yarn of the present invention will be described.

[0042] (I) Outline of an example of a glass filament manufacturing apparatus Figure 1 is a schematic side view showing an example of a glass filament bundle manufacturing apparatus for producing glass strands (glass filament bundles) that will become the glass yarn of the present invention, and Figure 2 is a top view of the glass filament bundle manufacturing apparatus of Figure 1.

[0043] As shown in Figure 1, the glass filament bundle manufacturing apparatus 300 comprises a bushing 100 for melting glass raw materials and a spinning apparatus 200 for spinning the molten glass to produce glass filaments. Note that in Figure 1, a portion of the side wall of the bushing 100 has been omitted to allow visibility of the inside.

[0044] In Figure 1, the bushing 100 is located at the top of the glass filament bundle manufacturing apparatus 300 and melts the glass raw material that is fed in. The spinning apparatus 200 is located at the bottom of the bushing 100 and spins glass filaments by extruding the molten glass, which has been melted in the bushing 100, from the nozzle 40 of the nozzle plate 30, which will be described later. In this embodiment, the spinning apparatus 200 also manufactures glass filament bundles by aligning multiple glass filaments into a single bundle.

[0045] The configuration of each part of the bushing 100 and the spinning apparatus 200 will be described below. The following description will follow the directions shown in Figure 1, namely up, down, front, back, right, and left. The description will follow these directions, however, the present invention is not limited by these directions.

[0046] (1) Bushing 100 As shown in Figure 1, the bushing 100 comprises a melting section 20, which is a region for melting the glass raw material that is introduced, and a nozzle plate 30 on which a plurality of nozzles 40 are formed for discharging the molten glass.

[0047] (a) Molten part 20 The melting section 20 comprises a first region 21 and a second region 23. The input port 10 is included in the first region 21 and is formed by a cylindrical body that penetrates vertically, and is provided at the upper end of the first region 21. Furthermore, the input port 10 is formed to be smaller than, for example, the second region 23 when viewed from above, thereby reducing the opening of the melting section 20 by the input port 10 and suppressing an excessive drop in temperature inside the melting section 20. The first region 21 and the second region 23 are equipped with a housing for melting the glass raw material introduced from the input port 10. As shown in Figure 2, this housing is formed in a roughly rectangular parallelepiped shape with an internal space by combining a pair of side walls 101a and 101b facing each other in the left-right direction, 101c and 101d facing each other in the front-rear direction, and an upper wall 102, with a nozzle plate 30 positioned at the bottom. The melting section 20 is made of a refractory material, which will be described later. Furthermore, as shown in Figure 1, the internal space of the melting section 20 is arranged from top to bottom by partition members 50, which are described later. The internal space is divided into a first region 21 and a second region 23 from top to bottom by the partition members 50. The first region includes, in the vertical direction, a region 27 in which the glass raw material is not completely melted and remains solid (solid glass raw material region) and a region 29 in which the glass raw material is completely melted and no solid glass raw material exists. The melting section 20 is also provided with a heating means 70 for melting the glass raw material. In Figure 1, molten glass is shown as GL, and glass raw material in which at least a portion remains solid is shown as GS. The components constituting the melting section 20 will be described in detail below.

[0048] As shown in Figures 1 and 2, heating means 70a and 70b are provided on the right and left side walls 101a and 101b of the melting section 20, respectively. Each of the heating means 70a and 70b includes electrode terminals, and a voltage is applied from a power source (not shown). As a result, a current flows through the bushing 100 in the direction between the heating means 70a and 70b, i.e., in the left-right direction, and the melting section 20 is heated. The heating means 70 applies a voltage to the melting section 20 to adjust the melting temperature of the molten glass in the melting section 20, for example, heating it so that the viscosity of the molten glass is 400 poise or less. In addition, the heating means 70 is configured to adjust the nozzle temperature of the nozzle 40 by heating the nozzle plate 30 in addition to the inside of the housing, thereby adjusting the spinning speed and diameter of the glass filament extruded from the nozzle 40.

[0049] Furthermore, the heating means 70 can individually control the nozzle temperature of the nozzle 40 and the melting temperature of the melting section 20. This allows for diverse control of the extrusion state of molten glass from the nozzle 40. However, since the molten glass melted in the melting section 20 is ultimately extruded from the nozzle 40 to produce glass filaments, it is important to adjust the nozzle temperature during extrusion. Therefore, it is preferable to use the heating means 70 to adjust the melting temperature based on the nozzle temperature and extrude the molten glass from the nozzle 40 to produce the desired glass filaments.

[0050] (b) Partition member 50 As shown in Figure 1, the partition member 50 is positioned between the first region 21 and the second region 23. As shown in Figure 3, the partition member 50 is formed in a rectangular plate shape corresponding to the rectangular parallelepiped shape of the molten section 20. The partition member 50 is attached to the side walls 101a to 101d of the molten section 20 by welding or the like, for example, so that the plate-shaped surface is aligned in the left-right direction. As shown in Figures 1 and 3, the partition member 50 may be installed so as to be parallel to the nozzle plate 30 in a side view, but in some cases it may be installed in a V-shape, W-shape, U-shape, inverted V-shape, inverted W-shape, etc. in the vertical direction. In addition, one or more partition members may be installed, preferably one to two. If three or more are installed, the pressure loss in the molten furnace will become too large, so it is preferable to install fewer than three. In addition, multiple partition plates with the same opening shape may be installed, or multiple partition plates with different opening shapes may be installed.

[0051] Furthermore, the partition member 50 has multiple rectangular, circular, elliptical, polygonal, or arbitrary shape openings 51 that penetrate its plane vertically. The openings 51 may be arranged alternately or in a grid pattern.

[0052] (c) Nozzle plate 30 As shown in Figure 1, a nozzle plate 30 is provided at the bottom of the second region 23 of the molten section 20. As shown in Figures 4 and 5, the nozzle plate 30 is formed in a rectangular plate shape corresponding to the rectangular parallelepiped shape of the molten section 20 and has a plate-like portion 31 having a predetermined thickness, and a plurality of nozzles 40 protruding downward from the plate-like portion 31. The plate-like portion 31 is attached to the side walls 101a to 101d of the molten section 20 by, for example, welding, so that the plate-like surface is aligned in the left-right direction, and constitutes the bottom wall of the molten section 20.

[0053] As shown in Figure 5, the nozzle 40 has a cylindrical projection 42 that protrudes downward from the lower surface of the plate-shaped portion 31. The nozzle 40 has a cylindrical through-hole 41 that penetrates from the upper surface of the plate-shaped portion 31 to the lower end of the projection 42. The molten glass in the second region 23 is received by the plate-shaped portion 31 and discharged from the through-hole 41 of the nozzle 40.

[0054] The number of nozzles 40 formed on such a nozzle plate 30 is approximately 30 to 500 if the nozzle plate 30 is approximately 50 mm x 500 mm.

[0055] In this embodiment, the expressions "molten glass is extruded from the nozzle 40" and "glass filament is extruded from the nozzle 40" are used, and both expressions have the same meaning. At least one of the following is extruded from the nozzle 40: molten glass that is being cooled and molten glass filament that has been cooled. In other words, the nozzle 40 extrudes in one of the following states: molten glass that is being cooled is extruded from the nozzle 40, molten glass filament that has been cooled is extruded, or a mixture of molten glass and glass filament.

[0056] The inner diameter d1 of the nozzle 40 should be approximately 0.8 mm to 1.2 mm. The thickness of the nozzle 40 should be (outer diameter d2 / inner diameter d1) approximately 1.85 to 2.20, and in some cases, it may be approximately 2.20 to 2.50.

[0057] (2) Spinning machine 200 Next, a spinning apparatus 200 that extrudes molten glass from a nozzle 40 to spin glass filaments will be described. The spinning apparatus 200 includes a sizing agent tray 201 for applying a sizing agent to the glass filaments extruded from the nozzle 40, a bundling mechanism 202 for bundling the glass filaments into a predetermined number of glass filament bundles, a crisscrossing mechanism 206 for crisscrossing the glass filament bundles, and a winding roller 211 for winding up the glass filament bundles.

[0058] The sizing agent tray 201 is equipped with a sizing agent supplied to the tray 201, and an applicator (not shown) that picks up the sizing agent and applies it to the glass filament by bringing the picked-up sizing agent into contact with the glass filament. Alternatively, the sizing agent can be applied to the glass filament by spraying or other means instead of using the sizing agent tray 201.

[0059] The focusing mechanism 202 includes a horizontal focusing shaft 203 that is rotationally driven by a motor or the like, and a plurality of focusing rollers 205 fixed to the focusing shaft 203. In this embodiment, for example, two focusing rollers 205 are fixed to the focusing shaft 203. Therefore, the plurality of glass filaments extruded from the through hole 41 of the nozzle 40 are separated into two fiber bundles by each of the two focusing rollers 205 as the focusing shaft 203 rotates. Before being separated into two fiber bundles by the focusing rollers 205, each glass filament is introduced into a focusing agent tray 201 containing a focusing agent, and the focusing agent is applied.

[0060] The traverse mechanism 206 includes a horizontal traverse shaft 207 that is rotationally driven by a motor or the like, and traverse members 209 corresponding to each of the three converging rollers 205. Each fiber bundle, which has been gathered by the three converging rollers 205, is traversed by the traverse members 209 due to the rotational drive of the traverse shaft 207, and is evenly wound onto the winding roller 211. The winding roller 211 rotates around a predetermined axis of rotation, and the rotational speed and rotational driving force are adjusted. This adjusts the spinning tension (tensile tension) and spinning speed of the molten glass discharged from the nozzle 40, and the fiber bundles are wound up. Examples of spinning speeds include 1300 m / min to 4000 m / min. The resulting glass filament bundles are then twisted using a ring twisting machine or the like to produce glass yarn.

[0061] (3) Outline of the manufacturing method of glass filaments Next, we will explain the flow from when the glass raw material is fed into the bushing 100, when the glass filament is extruded from the nozzle 40, and when it is wound up in the spinning device 200. First, the glass raw material is fed into the first region 21 of the molten section 20 of the bushing 100 one after another from the input port 10, and the glass raw material is melted. Therefore, the first region 21 includes, in the vertical direction, a region 27 in which the glass raw material is not completely melted and remains in solid form (solid glass raw material region), and a region 29 in which the glass raw material is completely melted and no solid glass raw material exists. A voltage is applied to the molten section 20 by heating means 70 (70a, 70b). The first region 21 of the molten section 20, region 29 where the glass raw material is completely melted and no solid glass raw material exists, is heated to a temperature above the softening point of the glass material, preferably above the nozzle temperature, more preferably above the nozzle temperature, and at a temperature where the viscosity of the glass material is 400 poise or less, even more preferably above the nozzle temperature, and at a temperature where the viscosity of the molten glass is 100 poise or less. For example, it is heated to 1500°C to 1700°C, preferably 1500°C to 1650°C, more preferably 1550°C to 1630°C. In this invention, the melting temperature is the temperature at which the molten glass inside the bushing 100 reaches its highest temperature.

[0062] The molten glass melted in the first region 21 comes into contact with the partition member 50 shown in Figure 3 at the bottom of the first region 21 and flows towards the opening 51, mixing together as it flows out into the second region 23 through a plurality of openings 51 arranged at predetermined intervals. As a result, a generally homogeneous molten glass flows out into the second region 23 in a generally uniform manner, filling the second region 23.

[0063] Next, the molten glass is supplied to the nozzle plate 30 at the bottom of the second region 23. The temperature of the nozzle plate 30 is adjusted by the heating means 70 and varies depending on the glass material, but for example, it can be between 1300°C and 1470°C.

[0064] Furthermore, as mentioned above, the molten glass is supplied to the nozzle plate 30 after the solid components within the molten glass have been sufficiently reduced in the partition member 50. Therefore, molten glass with a low solid component content can be discharged from the nozzle 40, thereby suppressing a decrease in the tensile strength of the glass product.

[0065] (4) Fireproof material To melt the glass raw material, at least the molten portion 20 of the bushing 100 is formed of a refractory material. Examples of refractory materials include, for example, metals consisting of elemental platinum; metals consisting of elemental rhodium; metals consisting of elemental palladium; metals consisting of elemental gold; metal compounds containing platinum; metal compounds containing rhodium; metal compounds containing palladium; metal compounds containing gold; alloys consisting of two or more elements selected from the group consisting of platinum, rhodium, palladium, and gold; and at least one selected from the group consisting of refractory bricks. Other refractory materials include molybdenum, graphite, tin oxide, ceramics, alumina, chromium oxide, magnesia, zircon, zirconia, and oxides. It includes at least one selected from the group consisting of yttrium. Furthermore, the refractory material may also include combinations of the materials described above, for example, an alloy of multiple materials may be used as the refractory material. Alternatively, multiple refractory materials may be combined as layers, for example, in a furnace with a refractory brick exterior wall, a plate or coating of platinum or a platinum-rhodium alloy may be formed on the interior wall.

[0066] Furthermore, the refractory material is not limited to the molten portion 20. For example, at least one of the nozzle plate 30 or the partition member 50 may be formed from a refractory material.

[0067] (5) Glass raw materials The glass raw materials introduced into the bushing 100 include solid glass, etc. Solid glass is glass that has been melted from glass raw materials such as powder and molded into predetermined shapes such as rods, spheres (marbles), flakes, or scales.

[0068] The glass composition constituting the above-mentioned glass raw material can be the same glass composition as the glass material constituting the glass filament.

[0069] (II) Main features of the glass yarn manufacturing method of the present invention In the glass yarn manufacturing method of the present invention, during glass filament spinning by indirect method, the temperature of the solid glass raw material presence region 27 of the bushing 100 is (T in ) and the temperature (T) near the nozzle plate 30 where the glass filament is spun. out ) difference ((T out )-(T in It is important to control the spinning process to stay within a specific temperature range.

[0070] That is, T out -T in By setting the temperature to 10-200°C, preferably 50-150°C, more preferably 60-120°C, and especially preferably 60-90°C, glass filament spinning can be performed while maintaining the stability of the glass liquid surface, resulting in reduced variation in the discharge volume and enabling the spinning of glass filaments with good Worcester spot. Here, T in This is thermocouple 81, T in Figure 6. out This can be measured using the thermocouple 82 in Figure 1. In Figure 6, the thermocouple 81 is welded or otherwise joined to the side wall constituting the inlet 10, and the thermocouple 82 is welded or otherwise joined in the vertical direction to the side wall 101d at a height of 2 to 10 mm above the plate-shaped portion 31 of the nozzle plate 30.

[0071] To explain this more specifically using Figure 6, T out -T in If the temperature is below 10°C, the generation of bubbles in the molten glass in the solid glass raw material region 27 near the inside of the input port 10 tends to increase. When there are many bubbles in the molten glass 2 in the solid glass raw material region 27, the liquid level of the molten glass 2 becomes unstable, and the inclusion of many bubbles leads to a decrease in the head pressure of the molten glass, resulting in variations in the amount of molten glass discharged. On the other hand, T out -Tin When the temperature exceeds 200°C, the temperature of region 29 in the first region 21, where the glass raw material is completely melted and no solid glass raw material exists, reaches the melting temperature (T). m ) and T out The difference between this and the temperature (melting temperature) of region 29 in region 1 21, where the glass raw material is completely melted and no solid glass raw material exists. in When comparing the difference between and , the temperature (melting temperature) of region 29, where the glass raw material is completely melted in region 21 and no solid glass raw material exists, and T in The difference between the two becomes too large. In this case, the convection of the molten glass circulating from the first region 21 towards the inlet 10 becomes too large, the liquid level of the molten glass becomes unstable, and variations in the discharge volume tend to occur.

[0072] Glass raw materials are sequentially introduced into the inlet 10 by detecting the liquid level, and each time glass raw materials are introduced into the bushing 100, the molten glass inside the inlet 10 is cooled. In the conventional technology, although the melting temperature and the temperature near the nozzle plate were controlled, the control of the temperature of the region (solid glass raw material region) 27 near the inside of the inlet 10, where the glass raw materials are not completely melted and remain solid, was not considered. In the present invention, by focusing on the temperature of the solid glass raw material region) 27 and controlling it to be within a specific range based on the temperature near the nozzle plate 30, it was found that the liquid level of the molten glass is stabilized, variations in the discharge volume are reduced, and glass filaments with good Worcester spot are spun.

[0073] T out The adjustment method involves adjusting by the heating means 70, T out Based on T in One example is adjusting T inMethods for adjusting the temperature include preparing insulating material such as porous ceramic, selecting the appropriate type and thickness, and placing it around the inlet 10 or on the upper wall 102; adding a heater above the inlet 10 to adjust the temperature; installing a water pipe made of any metal or alloy to adjust the temperature; or supplying any gas component to adjust the temperature. [Examples]

[0074] The present invention will be described in detail below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

[0075] <Manufacturing of glass yarn> In each example and comparative example, glass strands were obtained by an indirect method using the glass filament manufacturing apparatus shown in Figures 1 to 6. In each example and comparative example, a porous ceramic plate was placed on the upper wall 102 as an insulating material, and the thickness of the porous ceramic plate was set as shown in Table 1. out -T in The following was controlled. In addition, in each example and comparative example, the composition of the glass material constituting the glass filament was as shown in Table 1. Also, as shown in Figure 6, the temperature T of the solid glass material presence region (27) of the bushing 100 was controlled. in The temperature T near the nozzle plate where the glass filament is spun was measured using thermocouple 81. out The temperature was measured by thermocouple 82, and the temperature of region 29 where the glass raw material in region 21 is completely melted and no solid glass raw material is present (melting temperature, T) was measured. m ) was measured and controlled by thermocouple 83. T in each example and comparative example out -T in , T m -T in , T m -T out This is shown in Table 1.

[0076] The glass strands obtained in each example and comparative example were twisted. A ring twisting machine was used to twist the strands to the number of twists shown in Table 1, thereby obtaining glass yarn.

[0077] <Evaluation Method> 1. Average fiber diameter of glass filaments The obtained glass yarn was embedded in epoxy resin (product name 3091, manufactured by Marumoto Storuas Co., Ltd.) so that its cross-section could be observed, and then hardened. After polishing to allow observation, it was observed using a scanning electron microscope (product name JSM-6390A, manufactured by JEOL Ltd.) at a magnification of 1000x. The diameter of all glass filaments constituting the glass yarn (the largest part) was measured, and the average value was calculated. This average value was taken as the average fiber diameter of the glass filaments. The results are shown in Table 1.

[0078] 2. Glass yarn count The measurements were performed in accordance with the method specified in "7.1 Count" of "General Test Methods for Glass Fibers" in JIS R 3420 2013. The results are shown in Table 1.

[0079] 3. Worcester variegated glass yarn Measurements were taken using a Zerbeger Worcester AG Worcester Tester, model number 4-CX-R1.7, under the following measurement conditions. The results are shown in Table 1. (Measurement conditions) Measurement mode: Normal Yarn feeding speed: 200m / min Measured thread length: 500m Twister: Z-twist, 12,000 turns / min Disc tension strength: 10%

[0080] 4. Number of twists in glass yarn Measurements were taken in accordance with JIS R 3420:2013 7.5. The results are shown in Table 1.

[0081] 5. The number of hollow fibers in the multiple glass filaments that make up the glass yarn. For the number of hollow fibers, in Examples 1-3, 5, and Comparative Examples 1-4, 100 arbitrary 1cm lengths of glass yarn were cut along the longitudinal direction, and measurement samples were taken. In Example 4, 200 arbitrary 1cm lengths of glass yarn were cut along the longitudinal direction, and measurement samples were taken. Next, each 1cm sample was immersed in benzyl alcohol, and the glass filaments in the glass yarn were loosened so that each one could be observed side by side. An LED light source was shone from above, and the samples were observed at 10x magnification using an optical microscope, and the number of hollow fibers (fibers / 10,000 locations) was counted. The results are shown in Table 1.

[0082] 6. Fibers of glass yarn Set each glass yarn package so that its axial direction is horizontal, and the cylindrical bobbin A snail guide is set 250 mm from the tip (the tip of the gripping part 21 in Figure 1). The glass yarn was then unwound 20 km at a yarn speed of 300 m / min in the direction of the tip of the gripping part 21, and the number of fibers was measured. A yield of 4.0 fibers or less per kilometer was considered acceptable.

[0083] [Table 1]

[0084] The glass yarns of Examples 1 to 7 are glass yarns formed by bundling multiple glass filaments, wherein the glass material constituting the glass filaments contains 40 to 60% by mass of SiO2 and 15 to 35% by mass of B2O3, the number of glass filaments is 30 to 120, the average fiber diameter of the glass filaments is 3 to 6 μm, the count of the glass yarn is 0.3 to 6 tex, and the Worcester spot of the glass yarn is 0.5 to 2.0%, thus suppressing the generation of fluff when the yarn is made into glass cloth.

[0085] On the other hand, in Comparative Examples 1 to 3, the Worcester spotting of the glass yarn exceeded 2.0%, indicating that in glass yarns formed by bundling multiple glass filaments, where the glass material constituting the glass filaments contains 40-60% by mass of SiO2 and 15-35% by mass of B2O3, and the average fiber diameter of the glass filaments is 3-6 μm, the generation of fluff when made into glass cloth could not be suppressed. [Explanation of Symbols]

[0086] 81, 82, 83: Thermocouples 70: Heating means 100: Bushing 200: Spinning machine 300: Glass filament bundle manufacturing equipment

Claims

1. A glass yarn formed by bundling together multiple glass filaments, The glass material constituting the glass filament is SiO ２ 40-60% by mass, B ２ O ３ It contains 15 to 35% by mass of The number of glass filaments is 30 to 120. The average fiber diameter of the glass filament is 3 to 6 μm. The glass yarn has a count of 0.3 to 6 tex. A glass yarn having a Worcester spot of 0.5-2.0%.

2. The glass yarn according to claim 1, wherein the number of twists of the glass yarn is 0.3 to 1.2 times / 25 mm.

3. A glass cloth woven using the glass yarn described in claim 1 or 2 as warp and / or weft.

4. A melting section that melts the input glass raw materials to produce molten glass, A nozzle plate provided at the lower part of the melting section, Using a bushing that includes a heating means for heating the molten portion and the nozzle plate, A method for manufacturing glass yarn according to claim 1 or 2, comprising the step of manufacturing a glass filament, The molten portion includes a region in which the glass raw material is not completely melted and remains solid, and a region in which the glass raw material is completely melted and no solid glass raw material exists. Temperature T in the region where the glass raw material is not completely melted and remains solid. ｉｎ and the temperature T near the nozzle plate ｏｕｔ The difference (T ｏｕｔ -T ｉｎ A method for producing glass yarn according to claim 1 or 2, wherein the temperature is set to 10 to 200°C to produce a glass filament.

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