Bushing and modified cross-section glass fiber manufacturing method

Abstract

To provide a bushing that can stably manufacture a desired irregular shaped cross section glass fiber, and to provide a manufacturing method for manufacturing an irregular shaped cross section glass fiber using the bushing.SOLUTION: A bushing 4 includes: a base plate 41 extending in a predetermined one direction and including multiple cooling areas S in which a cooling member configured to be capable of cooling molten glass can be arranged; and multiple nozzles 5 including a nozzle hole 53 provided in the base plate 41 and formed into a flat shape in a tip part from which molten glass flows out, a pair of first wall parts 51 facing each other in a minor diameter direction of the nozzle hole 53 and having a recessed notch 54, and a pair of second wall parts 52 facing each other in a major diameter direction of the nozzle hole 53, where the multiple nozzles 5 are arranged so as to orient the first wall parts 51 in a direction of the cooling areas S.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an improvement in the manufacturing technology of modified cross section glass fibers. [Background technology]

[0002] Glass fibers with irregular cross sections, such as those with flattened cross sections like ovals or ellipses, are used in a variety of fields because they can provide a high reinforcing effect when mixed with resin to form a composite.

[0003] This type of modified cross-section glass fiber is generally produced by cooling molten glass while drawing it out from a nozzle of a bushing. In this case, since the cross-sectional shape of the produced glass fiber depends on the shape of the nozzle hole at the nozzle tip, when producing a modified cross-section glass fiber, the nozzle hole at the nozzle tip is often made flat.

[0004] However, even if a nozzle having a flat nozzle hole is used, if the viscosity of the molten glass drawn out from the nozzle is too low, the cross section of the molten glass directly below the nozzle tip is likely to be formed to be round due to surface tension, making it impossible to produce the desired modified cross section glass fiber.

[0005] Therefore, for example, in the nozzle of Patent Document 1, at the nozzle tip from which the molten glass flows out, a pair of long wall portions opposing each other in the minor diameter direction of the flat nozzle hole are each provided with a concave notch, and the viscosity of the molten glass is adjusted by cooling it using these concave notches. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-226579 A Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, studies have been conducted on improving productivity and producing strands with larger counts by increasing the amount of modified cross-section glass fibers drawn from one bushing. As described in Patent Document 1, by arranging cooling members near both notches, the number of nozzles provided in the bushing is reduced, and there are cases in which the productivity of modified cross-section glass fibers cannot be sufficiently increased.

[0008] Furthermore, when cooling the molten glass by disposing cooling members near both notches, the molten glass may be cooled too much, which may result in failure to stably mold the modified cross section glass fiber.

[0009] In view of the above circumstances, an object of the present invention is to stably produce a desired modified cross section glass fiber. [Means for solving the problem]

[0010] A bushing according to the present invention is a glass fiber manufacturing device comprising: a base plate extending in a predetermined direction and having a plurality of cooling regions in which a cooling member configured to be able to cool molten glass can be arranged; and a plurality of nozzles provided on the base plate, the nozzle holes each having a flattened nozzle hole at a tip end from which the molten glass flows out, a pair of first wall portions facing each other in a minor axis direction of the nozzle hole and having a concave notch, and a pair of second wall portions facing each other in a major axis direction of the nozzle hole, the plurality of nozzles being arranged so that the first wall portions face the direction of the cooling regions, and between the adjacent cooling regions, a first nozzle row in which the plurality of nozzles are arranged at a predetermined interval along the extension direction of the cooling regions, and a second nozzle row having an interval from the first nozzle row and in which the plurality of nozzles are arranged at a predetermined interval along the extension direction of the cooling regions are arranged, and the nozzles of the first nozzle row are arranged so that each of the notches provided in the pair of first wall portions of the nozzles in the first nozzle row can face the cooling regions.

[0011] According to this configuration, since the first nozzle row and the second nozzle row are arranged between the cooling members, it is possible to arrange more nozzles than in the past. Therefore, it is possible to improve the productivity of modified cross-section glass fibers, and since a large number of glass fibers can be obtained at one time, it is possible to manufacture strands with a large count. Furthermore, for the nozzles included in the first nozzle row, one of the notches faces the cooling member directly, and the other notch faces the cooling member through the gap between the nozzles of the second nozzle row, so that the molten glass can be prevented from being cooled too much. Therefore, the viscosity of the molten glass during molding can be appropriately adjusted, and the modified cross section glass fiber can be stably molded. When the other cutout faces only the nozzles of the second nozzle row, the molten glass is not cooled.

[0012] In the present invention, it is preferable that the nozzles of the second nozzle row are arranged so that each of the notches provided in a pair of first wall portions of the nozzles in the second nozzle row can face the cooling region.

[0013] According to such a configuration, the viscosity of the molten glass drawn out from the nozzles included in the second nozzle row during molding can also be appropriately adjusted, and the modified cross section glass fiber can be stably molded.

[0014] In the present invention, it is preferable that the intervals between the plurality of nozzles in the first nozzle row and the intervals between the plurality of nozzles in the second nozzle row are narrower than the width of the tips of the nozzle notches in the nozzles.

[0015] According to this configuration, it is possible to reliably prevent the molten glass from being cooled too much.

[0016] The method for producing a modified cross-section glass fiber according to the present invention is characterized in that the modified cross-section glass fiber is produced using the above-mentioned bushing. With this configuration, it is possible to obtain the same effects as those of the configurations already described.

[0017] In the present invention, the molten glass is preferably E glass. Since E glass is resistant to devitrification, the productivity of modified cross section glass fiber is improved.

[0018] In the present invention, at the forming temperature, the molten glass is 10 2.0 ~10 3·5 It is preferable that the viscosity of the composition is 10 3·5 If the viscosity is less than 10 dPa·s, the viscosity of the molten glass does not become too high, so that the moldability of the glass fiber can be maintained good. 2.0 If the viscosity is above dPa s, the viscosity of the molten glass will not be too low, and the force of the surface force causing the molten glass to return to a circular cross section will be weakened, making it possible to increase the aspect ratio (longer diameter dimension / shorter diameter dimension) of the glass fiber. Effect of the Invention

[0019] According to the present invention, a desired modified cross section glass fiber can be stably produced. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a cross-sectional view showing an apparatus for producing a modified cross-section glass fiber according to one embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing the periphery of a nozzle of the bushing of FIG. [Diagram 3] FIG. 3 is an enlarged bottom view showing the periphery of the nozzle of the bushing in FIG. [Figure 4] FIG. 4 is a diagram showing a nozzle of a bushing according to an embodiment of the present invention, in which (a) is a side view, (b) is a cross-sectional view taken along A1-A1 of (a), and (c) is a cross-sectional view taken along B1-B1 of (a). [Diagram 5] FIG. 5 is an enlarged bottom view showing the periphery of the nozzle of the bushing in FIG. [Figure 6] FIG. 6 is an enlarged bottom view showing the periphery of a nozzle of a bushing according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Preferred embodiments will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in each drawing, components having substantially the same functions may be referred to by the same reference numerals.

[0022] (One embodiment of a manufacturing apparatus and manufacturing method for modified cross section glass fiber) As shown in Fig. 1, the modified cross section glass fiber manufacturing apparatus 10 according to this embodiment includes a glass melting furnace 1, a forehearth 2 connected to the glass melting furnace 1, and a feeder 3 connected to the forehearth 2. Here, in an orthogonal coordinate system consisting of XYZ shown in Fig. 1, the X direction and the Y direction are horizontal directions, and the Z direction is vertical directions (hereinafter the same).

[0023] Molten glass G is supplied from a glass melting furnace 1 through a forehearth 2 to a feeder 3 and is stored in the feeder 3. Although one feeder 3 is shown in FIG. 1, a plurality of feeders 3 may be connected to the glass melting furnace 1. In addition, a fining furnace may be provided between the glass melting furnace 1 and the forehearth 2.

[0024] In this embodiment, the molten glass G is made of E glass, but it may be made of other glass materials such as D glass, S glass, AR glass, and C glass.

[0025] A bushing 4 is disposed at the bottom of the feeder 3. The bushing 4 is attached to the feeder 3 via a bushing block or the like. The bottom of the bushing 4 is configured with a base plate 41 as shown in FIG. 2, and a plurality of nozzles 5 are provided on the base plate 41. The base plate 41 is also provided with a plurality of cooling regions S extending in the Y direction, which is a predetermined direction, and in which cooling pipes 6 can be arranged (see FIG. 3). The cooling regions S are provided with cooling pipes 6 as cooling members.

[0026] The molten glass G stored in the feeder 3 is drawn downward from a plurality of nozzles 5 provided on the base plate 41 of the bushing 4, and the glass fiber (monofilament) Gm is produced. At this time, the viscosity of the molten glass G at the forming temperature is 10 2.0 ~10 3·5 dPa·s (preferably 10 2.5 ~10 3·3 The viscosity of the molten glass G at the forming temperature is set within the range of dPa·s. The viscosity of the molten glass G at the position where it flows into the nozzle 5 is the viscosity of the molten glass G. A bundling agent is applied to the surface of the glass fibers Gm by an applicator (not shown), and 100 to 10,000 fibers are spun into one strand Gs. The count of the strand Gs depends on the glass fibers Gm to be spun, and the greater the number of glass fibers Gm, the greater the count of the strand Gs. The spun strand Gs is wound as a fiber bundle Gr on a collet 7 of a winding device. The strand Gs is cut to a predetermined length, for example, about 1 to 20 mm, and used as a chopped strand.

[0027] At least a portion of the glass melting furnace 1, the forehearth 2, the feeder 3, the bushing 4, the nozzle 5 and the cooling pipe 6 is made of platinum or a platinum alloy (for example, a platinum-rhodium alloy).

[0028] In order to adjust the viscosity of the molten glass G, one or more elements selected from the forehearth 2, the feeder 3, and the bushing 4 may be heated by electrical heating or the like.

[0029] As shown in FIG. 2 and FIG. 3, the nozzle 5 has, at the tip (lower portion), a pair of long wall portions (first wall portions) 51 facing each other in the X direction, a pair of short wall portions (second wall portions) 52 facing each other in the Y direction, and a flat (elliptical in this embodiment) nozzle hole 53 defined by the long wall portions 51 and the short wall portions 52. Each long wall portion 51 is provided with a notch 54, and a part of the nozzle hole 53 communicates with the external space of the nozzle 5 through the notch 54. In this embodiment, the major axis direction of the nozzle hole 53 coincides with the Y direction, and the minor axis direction of the nozzle hole 53 coincides with the X direction. In this embodiment, the X direction dimension of the short wall portions 52 is shorter than the Y direction dimension of the long wall portions 51. Of course, the dimensional relationship between the walls 51 and 52 is not particularly limited. The cross-sectional shape of the nozzle hole 53 may be an ellipse or the like other than an ellipse.

[0030] As shown in Figs. 4(a) to (c), the notches 54 provided in each long wall portion 51 of the nozzle 5 are trapezoidal with the same dimensions. In detail, in this embodiment, the notch 54 has a center point T1 of the upper base on the center line M1 of the long wall portion 51, and is an isosceles trapezoid (the upper base is shorter than the lower base) symmetrical with respect to the center line M1. The interior angle θ1 (the interior angle on both sides of the upper base) is, for example, greater than 90° to 160° (preferably 110° to 150°). In this embodiment, the nozzle hole 53 is a flat oval shape, and has a constant shape in the Z direction. As shown in Fig. 4(c), at the tip of the nozzle 5, the nozzle hole 53 has a ratio (a / b) of the X-direction dimension (minor axis dimension) b to the Y-direction dimension (major axis dimension) a in the range of 1.5 to 20 (preferably 3 to 10).

[0031] According to such a configuration, it is possible to suppress deformation of the shape caused by the notch 54 of the nozzle 5 while ensuring a sufficient opening area of ​​the notch 54. Therefore, it is possible to stably mold the glass fiber Gm having a noncircular cross section such as a flattened cross section. In other words, the variation in the cross-sectional shape of the manufactured glass fiber Gm is reduced.

[0032] As long as the nozzle 5 has a flat nozzle hole 53 at the tip defined by a long wall portion 51 and a short wall portion 52, the shape of the base end (upper portion) may be the same as or different from the shape of the tip of the nozzle 5.

[0033] It is preferable that 200 to 10,000 nozzles 5 are arranged on the base plate 41. By arranging the above number of nozzles 5, a strand Gs with a large count can be obtained. It is preferable that 1,500 or more nozzles 5 are arranged on the base plate 41.

[0034] The cooling pipe 6 is configured to circulate cooling water F as a fluid therein to provide a cooling effect. The cooling pipe 6 is a plate-like body, and a plurality of cooling pipes 6 are arranged so that the plate surface is aligned in a certain direction (vertical direction). In this embodiment, the cooling pipe 6 is integrally provided in the cooling area S of the base plate 41, but may be provided away from the bottom of the bushing 4. The cooling pipe 6 may also be a cylindrical body. The height position of the cooling pipe 6 can be appropriately adjusted according to the cooling conditions of the molten glass G. For example, the cooling pipe 6 may be arranged above the tip of the nozzle 5 so as not to directly face the molten glass G drawn out from the nozzle 5, or may be arranged to straddle both the nozzle 5 and the molten glass G drawn out from the nozzle 5. The cooling member is not limited to the cooling pipe 6, and may be a cooling fin that induces an air flow to provide a cooling effect.

[0035] As shown in FIG. 3 and FIG. 5, in the base plate 41 of the bushing 4, a plurality of nozzle rows L1, L2 are arranged in parallel with an interval in the X direction between adjacent cooling regions S. Each nozzle row L1, L2 is configured by arranging a plurality of nozzles 5, the major axis direction of the nozzle hole 53 of which is oriented in the Y direction, on the same straight line extending in the Y direction. The cooling pipe 6 is arranged between the nozzle rows L1, L2 adjacent to each other in the X direction and in parallel with the nozzle rows L1, L2. In this embodiment, the nozzle row L1 and the nozzle row L2 are the same except for the arrangement position of the nozzle 5 in the Y direction. As a result, as shown in FIG. 5, the cooling pipe 6 faces the notch 54a of the nozzle 5 adjacent to the cooling pipe 6, and the molten glass G flowing through the nozzle 5 is cooled through the notch 54a. Specifically, at the tip of the nozzle 5, the molten glass G is rapidly cooled by the cooling pipe 6 from a temperature of 1000°C or more. The cooling pipe 6 also functions to cool the bushing 4 and the nozzle 5, suppressing their thermal deterioration and improving their durability.

[0036] In addition, the notch 54b of the nozzle 5 not adjacent to the cooling tube 6 also faces the cooling member 6 through the gap area between the nozzles 5 included in the adjacent nozzle rows (the nozzle row adjacent to the nozzle row L1 is L2, and the nozzle row adjacent to the nozzle row L2 is L1), so that the molten glass G can be prevented from being cooled too much. Therefore, the viscosity of the molten glass G during molding can be appropriately adjusted, and the irregular cross-section glass fiber can be stably molded. That is, the molten glass G on the notch 54a side of the nozzle 5 is cooled rapidly because it directly faces the cooling tube 6, and the molten glass G on the notch 54b side of the nozzle 5 is cooled more slowly than the molten glass G on the notch 54a side because it faces the cooling tube 6 at a predetermined distance. Therefore, the molten glass G on the notch 54a side quickly solidifies and becomes difficult to deform, while the molten glass G on the notch 54b side can be deformed to some extent until it solidifies. In order to stably mold the irregular cross-section glass fiber having a high flattening ratio, it is necessary to rapidly solidify only a part of the molten glass G to prevent the cross section of the fiber from becoming circular, while gradually solidifying the other part. For example, if the molten glass G on both major diameter sides is rapidly solidified, the flattening ratio becomes high, but the glass fiber is likely to break.

[0037] As shown in FIG. 6, if the notches 54b of the nozzles 5 that are composed only of the nozzle row L1 and are not adjacent to the cooling pipes 6 do not face the cooling member 6, the molten glass G will not be cooled sufficiently.

[0038] In the present embodiment, the distances D1 and D2 are narrower than the width W at the tips of the notches 54a and 54b, so that the molten glass G can be prevented from being cooled too much.

[0039] The intervals D1 and D2 between the nozzles 5 are preferably 1 to 10 mm, and more preferably 1 to 5 mm. This allows more nozzles 5 to be arranged on the base plate 41. The width W at the tip of the notch 54 is preferably 2 to 20 mm. The ratio (W / D(D1, D2)) of the intervals D1 and D2 to the width W at the tip of the notch 54 can be, for example, 0.5 to 5, and is preferably 1.1 to 2.5.

[0040] The number of nozzles 5 included in each of the nozzle rows L1 and L2 is preferably 10 to 500 or less.

[0041] According to this embodiment in which modified cross section glass fibers are produced as described above, the following effects can be obtained.

[0042] In this embodiment, since the first nozzle row L1 and the second nozzle row L2 are arranged between the cooling regions S (cooling tubes 6), more nozzles 5 can be arranged compared to the conventional method. Therefore, the productivity of the irregular cross-section glass fiber can be improved. In addition, since many nozzles 5 are arranged, the number of glass fibers Gm obtained at one time is increased, and as a result, a strand Gs with a large count can be manufactured. Furthermore, for the nozzles 5 included in the first nozzle row L, one notch 54a directly faces the cooling tube 6, and the other notch 54b faces the cooling tube 6 through the gap region between the nozzles 5 of the second nozzle row L2, so that the molten glass G can be prevented from being cooled too much. Therefore, the viscosity of the molten glass G during molding can be appropriately adjusted, and the irregular cross-section glass fiber can be stably molded.

[0043] Furthermore, with respect to the nozzles 5 included in the second nozzle row L, one notch 54a faces the cooling tube 6 directly, and the other notch 54b faces the cooling tube 6 through the gap area between the nozzles 5 of the first nozzle row L1, thereby preventing the molten glass G from being cooled too much.

[0044] The manufacturing method of the modified cross section glass fiber according to the embodiment of the present invention has been described above, but the present invention is not limited to this, and various variations are possible without departing from the gist of the present invention.

[0045] In the above embodiment, the intervals D1 and D2 between the nozzles 5 are equal, but they may be different. In that case, the ratio D1 / D2 of D1 to D2 is preferably within a range of 0.5 to 2.0. [Explanation of symbols]

[0046] 1: glass melting furnace, 4: bushing, 41: base plate, 5: nozzle, 51: long wall portion (first wall portion), 52: short wall portion (second wall portion), 53: nozzle hole, 54: notch, 6: cooling pipe, 10: modified cross-section glass fiber manufacturing device, G: molten glass, Gm: glass fiber (monofilament), Gs: strand, S: cooling area, L1: first nozzle row, L2: second nozzle row, W: notch opening width

Claims

1. A base plate extending in a predetermined direction and including a plurality of cooling regions in which a cooling member configured to be able to cool molten glass can be disposed; a plurality of nozzles provided on the base plate, the nozzle holes having a flat shape at the tip portions from which the molten glass flows out, a pair of first wall portions facing each other in a minor axis direction of the nozzle holes and having concave notches, and a pair of second wall portions facing each other in a major axis direction of the nozzle holes; a plurality of the nozzles are arranged such that the first wall portion faces the cooling region, a first nozzle row in which a plurality of the nozzles are arranged at predetermined intervals between the adjacent cooling regions along the extending direction of the cooling regions; a second nozzle row having a plurality of nozzles arranged at predetermined intervals along a direction in which the cooling region extends, the second nozzle row being spaced from the first nozzle row; A bushing in which nozzles of the first nozzle row are arranged so that one of the notches provided in a pair of first wall portions of the nozzles in the first nozzle row faces the cooling member adjacent to the first nozzle row, and the other faces the cooling member adjacent to the second nozzle row through a gap area between the multiple nozzles in the second nozzle row.

2. 2. The bushing according to claim 1, wherein the nozzles of the second nozzle row are arranged so that one of the notches provided in a pair of first wall portions of the nozzles in the second nozzle row faces the cooling member adjacent to the second nozzle row, and the other of the notches faces the cooling member adjacent to the first nozzle row through a gap area between the multiple nozzles in the first nozzle row.

3. 3 . The bushing according to claim 1 , wherein a distance between the plurality of nozzles in the first nozzle row and a distance between the plurality of nozzles in the second nozzle row are narrower than a width of a tip of the nozzle notch in the nozzle.

4. A method for producing a modified cross-section glass fiber, comprising the steps of: producing a modified cross-section glass fiber by using the bushing according to any one of claims 1 to 3.

5. 5. The method for producing a modified cross section glass fiber according to claim 4, wherein the molten glass is E glass.

6. At the forming temperature, the molten glass is ２．０ ~10 ３．５ 6. The method for producing a modified cross section glass fiber according to claim 4 or 5, wherein the glass fiber has a viscosity of 100 dPa·s.

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