TW202202458A - Nozzle for deformed cross-section glass fiber, and manufacturing method of deformed cross-section glass fiber - Google Patents

Abstract

This nozzle 8 for deformed cross-section glass fiber, for manufacturing deformed cross-section glass fiber 2f from molten glass 2 flowing out of a nozzle hole 6, comprises the flat nozzle hole 6, which has an inlet 6a and an outlet 6b for the molten glass 2, and wall sections surrounding the nozzle hole 6, which comprise a pair of short wall sections 12 opposite in the long-diameter direction of the nozzle hole 6 and a pair of long wall sections 12 opposite in the short-diameter direction, wherein, viewing the nozzle hole 6 from the outlet 6b side, the average width of the bottom wall surface 12b of the short wall sections 12 is greater than the average width of the bottom wall surface 11b of the long wall sections 11.

Description

Nozzle for special-shaped section glass fiber, and manufacturing method of special-shaped section glass fiber

The present invention relates to a nozzle for producing a flat cross-section glass fiber from molten glass, and a method for producing the special-shaped glass fiber using the nozzle.

A cross-sectional glass fiber with a flat cross-section is produced as a type of glass fiber (refer to Patent Document 1). When the profiled cross-section glass fiber is kneaded and compounded with resin, a good reinforcing effect can be achieved, so it is used as fiber for fiber reinforced plastics (FRP), etc., and is used in various fields.

When producing a profiled glass fiber, for example, molten glass is supplied to a bushing from a feeder for flowing molten glass, and the molten glass is drawn out from a plurality of nozzles provided in the bushing and cooled. The shape of the nozzle hole provided in the nozzle is generally a flat hole shape (oval, oblate, etc.). [Prior Art Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2017/221471

[Problems to be Solved by Invention]

In the manufacture of profiled-section glass fibers, there are the following problems to be solved. That is, the molten glass flowing out of the nozzle hole is deformed so that the surface area becomes smaller due to the surface tension, so it is difficult to form a glass fiber with a high oblateness and an irregular cross-section.

The technical problem to be solved by the present invention in view of the above is to make it possible to manufacture a special-shaped glass fiber with a high aspect ratio when producing a special-shaped glass fiber. [Technical means to solve problems]

In order to solve the above-mentioned problems, the nozzle for glass fiber with irregular cross section of the present invention is provided with a nozzle hole having an inflow port and an outflow port of molten glass and having a flat cross section, and the nozzle hole includes: the length of the flat cross section of the nozzle hole A pair of short wall portions facing each other in the radial direction, and a pair of long wall portions facing each other in the short diameter direction of the flat cross section of the nozzle hole. Glass is made of profiled-section glass fiber, and the average width of the bottom wall of the short wall portion is wider than the average width of the bottom wall of the long wall portion.

When producing glass fibers with irregular cross-sections, in addition to the inner peripheral surface of the nozzle hole (including the inner wall surfaces of the short and long walls), the bottom walls of the short and long walls are also wetted with molten glass. At this time, the bottom wall surfaces of the short wall portion and the long wall portion can stretch the molten glass in the direction along the bottom wall surface, respectively, and the width of the bottom wall surface (the width along the thickness direction of the short wall portion, or the width along the thickness direction of the long wall portion) The wider the width), the easier it is to stretch the molten glass. Furthermore, in order to improve the oblateness of the produced irregular-section glass fiber, it is more advantageous to stretch the molten glass along the long diameter direction of the nozzle hole rather than the short diameter direction of the nozzle hole. Therefore, in this configuration, the average width of the bottom wall surface of the short wall portion is made wider than the average width of the bottom wall surface of the long wall portion, and the molten glass can be effectively stretched along the longitudinal direction of the flat cross section of the nozzle hole. As a result, the profiled glass fiber can be formed with a high aspect ratio.

It is preferable that the average width of the bottom wall surface of the short wall part of the nozzle for glass fibers with a special-shaped cross section of the present invention is 1.5 times or more the average width of the bottom wall surface of the long wall part.

According to this configuration, the effect of stretching the molten glass in the longitudinal direction of the flat cross-section of the nozzle hole can be effectively exhibited, and it is more advantageous in forming the glass fiber with a special-shaped cross-section at a high aspect ratio.

It is preferable that the area of the bottom wall surface of a short wall part is larger than the area of the bottom wall surface of a long wall part in the nozzle for glass fibers with a special-shaped cross-section of this invention.

According to this configuration, the effect of stretching the molten glass in the longitudinal direction of the flat cross-section of the nozzle hole can be effectively exhibited, and it is more advantageous in forming the glass fiber with a special-shaped cross-section at a high aspect ratio.

Furthermore, the method for producing a special-shaped glass fiber of the present invention for solving the above-mentioned problems is a method for producing a special-shaped glass fiber from molten glass flowing out from the nozzle hole using a nozzle for the special-shaped glass fiber provided with a nozzle hole, The nozzle hole has an inflow port and an outflow port of the molten glass and has a flat cross section, and includes: a pair of short walls facing each other in the long-diameter direction of the flat cross section of the nozzle hole, and a flat part of the nozzle hole. The short diameter direction of the cross section faces a pair of long wall parts, and the average width of the bottom wall surface of the short wall part is wider than the average width of the bottom wall surface of the long wall part.

According to this method, it is possible to obtain the same functions and effects as those described above with respect to the nozzle for glass fibers with a special-shaped cross section of the present invention. [Effect of invention]

According to the present invention, it is possible to manufacture fibers with high oblateness when manufacturing profiled glass fibers.

Hereinafter, the nozzle for irregular-section glass fibers and the manufacturing method of the irregular-section glass fibers according to the embodiment of the present invention will be described with reference to the attached drawings. In this specification, the numerical range indicated by "~" means that the numerical value described before and after the "~" is the range included in the minimum value and the maximum value, respectively.

As shown in FIG. 1 , the glass fiber with irregular cross section is manufactured by the manufacturing apparatus 1 . The manufacturing apparatus 1 is provided with: the feeder 3 which circulates the molten glass 2 produced|generated by the melting furnace which is not shown in the figure, the bushing plate 4 arrange|positioned below the feeder 3, and the connection for connecting the feeder 3 and the bushing plate 4. Tube 5. The molten glass 2 is supplied from the feeder 3 to the bushing 4 through the pipe 5 . Then, the molten glass 2 flows out from the nozzle holes 6 of the bushing plate 4 . The molten glass 2 is cooled and becomes 2 f of glass fiber (henceforth "glass fiber 2f") with a special-shaped cross section.

In the present embodiment, the molten glass 2 is made of E glass. However, it is not limited to this, The molten glass 2 may be comprised with other glass, such as D glass, S glass, AR glass, and C glass.

The feeder 3 is connected to a glass melting furnace (not shown). The feeder 3 circulates the molten glass 2 continuously produced in the glass melting furnace. The liquid level 2a of the molten glass 2 is formed in the feeder 3 inside.

The bushing 4 is provided with a bottom plate 7 at the bottom. The bottom plate 7 is provided with a plurality of nozzles 8 for glass fibers with irregular cross-sections (hereinafter referred to as "nozzles 8"), and cooling pipes 9 arranged in the vicinity of the nozzles 8. The plurality of nozzles 8 have the same configuration as each other. Although the details will be described later, the nozzle holes 6 provided in the respective nozzles 8 are formed to be flat.

The pipe 5 is formed in a cylindrical shape whose pipe axis extends in the vertical direction. The upper end of the tube 5 is connected to the bottom of the feeder 3 , and the lower end of the tube 5 is connected to the upper end of the bushing 4 . As long as the pipe 5 can connect the feeder 3 and the bushing 4, the shape and the extending direction of the pipe axis may be different from those of the present embodiment.

The bushing 4 , the tube 5 , the nozzle 8 , the cooling pipe 9 , etc., are partially or entirely made of platinum or a platinum alloy (for example, platinum-rhodium alloy). Also in the present embodiment, the entirety of the tube 5 in these components is made of platinum or platinum alloy.

The entire flow path from the connection portion of the feeder 3 and the tube 5 to the nozzle hole 6 of the bushing 4 is filled with the molten glass 2 . Thereby, the pressure (head pressure) for letting the molten glass 2 flow out from the nozzle hole 6 is determined by the height difference H between the nozzle hole 6 and the liquid level 2a of the molten glass 2 in the feeder 3 . Here, the height difference H can be adjusted by, for example, changing the length of the tube 5 .

The temperature and viscosity of the molten glass 2 when the glass fiber 2f is formed are set to 1100°C to 1250°C (preferably 1150°C to 1200°C) and 10 _2.6 dPa･s to 10 _3.8 dPa･s (preferably 10 _2.9 dPa･s~10 _3.3 dPa･s). The "temperature and viscosity of the molten glass 2" also referred to here refer to the temperature and viscosity of the molten glass 2 at the position where the molten glass 2 flows into the nozzle 8 . For the adjustment of the temperature and viscosity of the molten glass 2, for example, the bushing 4 and the tube 5 can be individually heated by any heating means (for example, an electric heating device). In addition, the temperature and viscosity of the molten glass 2 may be adjusted by heating the molten glass 2 and the feeder 3 in the glass melting furnace by electric heating or the like.

On the surface of the glass fiber 2f, a sizing agent is applied by an applicator (not shown). Thereby, hundreds to thousands of glass fibers 2f are spun into one strand 2s. The spun strand 2s is wound around the bobbin 10 of the winding device into a fiber bundle 2r. The strand 2s is cut into a length of about 1 mm to 20 mm, for example, to be used as a chopped strand.

As shown in FIGS. 2 and 3 , the nozzle 8 has a pair of long wall portions 11 and 11 and a pair of short wall portions 12 and 12 . A nozzle hole 6 having a flat cross section is formed by being surrounded by these long wall portions and short wall portions. The nozzle hole 6 has the inflow port 6a which lets the molten glass 2 flow in, and the outflow port 6b which lets the molten glass 2 flow out. The pair of long wall portions 11 and 11 are respectively provided with notch portions 13 which are opened toward the outflow port 6b side. Thereby, the nozzle hole 6 is made to communicate with the external space of the nozzle 8 through the notch part 13 .

The cooling pipe 9 cools the molten glass 2 by circulating cooling water 14 in the cooling pipe 9 . The outer shape of the cooling pipe 9 is formed in a plate shape, and the plate surface thereof is parallel to the long wall portion 11 . Here, although the cooling pipe 9 is provided integrally with the bottom plate 7 , it may be provided at a position separated from the bottom plate 7 . In addition, the cooling pipe 9 may be formed in a circular tube shape.

The height position of the cooling pipe 9 can be adjusted according to the cooling conditions of the molten glass 2 . As an example, the cooling pipe 9 may be arranged above the lower end of the nozzle 8 so that its plate surface does not face the molten glass 2 drawn from the nozzle 8 . On the other hand, the cooling pipe 9 can also be arranged across the upper and lower sides of the nozzle 8 with reference to the lower end thereof, whereby the plate surface of the cooling pipe 9 faces both the nozzle 8 and the molten glass 2 drawn from the nozzle 8 . Moreover, regarding the cooling of the molten glass 2, in addition to the cooling pipe 9, the cooling fin etc. which are cooled by air flow can also be used. In addition, the cooling pipe 9 is not an essential structure, and may be omitted.

On the base plate 7, the nozzle rows P of a plurality of rows are arranged in parallel with intervals therebetween. Each nozzle row P includes a plurality of nozzles 8 . The plurality of nozzles 8 belonging to the same nozzle row P are arranged so that the nozzle holes 6 formed thereon are located on the same straight line.

The above-mentioned cooling pipes 9 are arranged so as to extend parallel to the nozzle row P between two adjacent nozzle rows P and P. Thereby, the molten glass 2 in the nozzle hole 6 is cooled by facing the notch part 13 of the cooling pipe 9. Specifically, the molten glass 2 is rapidly cooled from a temperature of 1000° C. or higher by the cooling pipe 9 . Here, the cooling pipe 9 also has a function of improving the durability by cooling the bushing 4 (the bottom plate 7 ) and the nozzle 8 to suppress deterioration due to heat of these members.

As shown in FIGS. 4( a ) to ( c ), the notch portion 13 provided in the long wall portion 11 of each nozzle 8 is an isosceles trapezoid whose upper base is shorter than the lower base. Thereby, the opening width of the notch part 13 gradually expands from the inflow port 6a side of the nozzle hole 6 toward the outflow port 6b side. The depth of the cutout portion 13 (the length in the direction along the axis 6x of the nozzle hole 6) is set to 0.1 mm to 2 mm. This is because, when the depth of the notch portion 13 exceeds 2 mm, the glass fibers 2f are easily damaged because both ends in the longitudinal direction become too thin in the cross section of the glass fibers 2f to be produced.

The shape of the notch portion 13 is not limited to a trapezoid, and may be other shapes. It can also be, for example, a triangle, a semicircle, or a rectangle. However, even in the case of adopting other shapes, it is preferable that the opening width of the notch portion 13 gradually expands from the side of the inflow port 6a of the nozzle hole 6 to the side of the outflow port 6b.

As shown in FIG. 4 , in this embodiment, a single nozzle hole 6 is provided in one nozzle 8 . The nozzle hole 6 is formed in a long hole shape. The pair of long wall parts 11 and 11 face each other in the short diameter direction of the flat cross section of the nozzle hole 6 , and the pair of short wall parts 12 and 12 face each other in the long diameter direction of the flat cross section of the nozzle hole 6 . Here, the flatness ratio (ratio of the long diameter and the short diameter) of the nozzle holes 6 is set to 2 to 5. The inner peripheral surface of the nozzle hole 6 including the inner wall surface 11a of the long wall portion 11 and the inner wall surface 12a of the short wall portion 12 is made of platinum or a platinum alloy. Moreover, the inner wall surface 11a of the long wall part 11 is linear as shown in FIG.4(c), and the opposing inner wall surfaces 11a are mutually parallel.

The boundary 15 between the long wall portion 11 and the short wall portion 12 is the point at which the slope of the inner wall surface with respect to the left-right direction (Z direction) in FIG. 4(c) changes from 0, and the slope with respect to the left-right direction in FIG. The part with 0 is the long wall part 11 , and the part other than the slope 0 is the short wall part 12 .

The long wall portion 11 has a bottom wall surface 11b connected to the inner wall surface 11a. In addition, the bottom wall surface 11b of the portion of the long wall portion 11 where the cutout portion 13 is provided corresponds to the upper bottom of the isosceles trapezoid, or the portion that connects the upper bottom and the lower bottom. In the present embodiment, the bottom wall surface 11b is a flat surface (a flat surface orthogonal to the axis 6x at a portion corresponding to the upper bottom of the isosceles trapezoid). Similarly, the short wall portion 12 has a bottom wall surface 12b connected to the inner wall surface 12a. In the present embodiment, the bottom wall surface 12b is a flat surface orthogonal to the axis 6x. In addition, the bottom wall surface 11b and the bottom wall surface 12b are not necessarily flat surfaces, and may be surfaces having unevenness or curvature.

Here, as shown in FIG. 4( c ), when the nozzle hole 6 is viewed from the outflow port 6 b side, the width of the bottom wall surface 11 b of the long wall portion 11 (the short diameter along the flat cross section of the nozzle hole 6 ) The average value of the width in the direction) is the average width W1, and the average value of the width of the bottom wall surface 12b of the short wall portion 12 (the width in the longitudinal direction of the flat cross section of the nozzle hole 6) is the average width W2. At this time, the average width W2 is larger than the average width W1. Specifically, the average width W2 is preferably 1.5 times or more, more preferably 2 times or more, of the average width W1. Also in this embodiment, the thickness W11 of the long wall portion 11 is constant, so W1=W11, but the thickness of the short wall portion 12 is not constant (for example, W21≠W22≠W23). Therefore, the average width W2 is the average value of the thicknesses of the respective portions of the short wall portion 12 . Also in this embodiment, the area of the bottom wall surface 12b of the short wall portion 12 is larger than the area of the bottom wall surface 11b of the long wall portion 11 .

Hereinafter, the main function and effect of the manufacturing method of the glass fiber with a special-shaped cross section using the above-mentioned nozzle 8 will be described.

In the nozzle 8, when the bottom wall surface 11b of the long wall portion 11 and the bottom wall surface 12b of the short wall portion 12 are respectively wetted by the molten glass 2, the bottom wall surfaces 11b, 12b can direct the molten glass 2 toward the bottom wall surfaces 11b, 12b along the bottom wall surfaces 11b, 12b. stretch in the direction. Further, since the molten glass 2 is easily stretched as the widths of the bottom wall surfaces 11b and 12b are wider, the molten glass 2 can be drawn along the flat cross section of the nozzle hole 6 by the nozzle 8 having the average width W2 larger than the average width W1. Effectively stretch in the longitudinal direction. As a result, as shown in FIG. 5, it becomes possible to manufacture glass fiber 2f with a high aspect ratio. Here, the cross-sectional shape of the glass fiber 2f is formed in a shape close to an oblate shape.

Here, the nozzle for irregular cross-section glass fiber and the manufacturing method of irregular cross-section glass fiber of this invention are not limited to the structure and aspect demonstrated in the said embodiment. For example, in the above-described embodiment, the notch portion 13 is provided in each of the pair of long wall portions 11 , 11 , but the notch portion 13 is not necessarily provided and may be removed. In addition to the long hole shape, the nozzle hole 6 can also be an oval shape, a dumbbell shape, a rhombus shape, three consecutive circles, a rectangle, or the like.

Next, a second embodiment different from the above-described embodiment will be described. The configuration other than the nozzle 8 is the same as that of the above-described embodiment. Therefore, only the differences from the above-described embodiment will be described.

As shown in FIG. 6, the nozzle 18 of 2nd Embodiment has a pair of long wall part 21,21 and a pair of short wall part 22,22. The short wall portion 22 has a bottom wall surface 22b which is continuous with the inner wall surface 22a. The pair of long wall portions 21 and 21 are respectively provided with notch portions 23 which are opened toward the outflow port 6b side. The shape of the notch part 23 is the same as that of the above-mentioned embodiment.

The long wall portion 21 has an inner wall surface 21a and a bottom wall surface 21b which is continuous with the inner wall surface 21a. Furthermore, in the second embodiment, unlike the above-described embodiments, the inner wall surface 21a is not parallel to the outer wall surface 21c, but the inner wall surface 21a is formed so as to approach the outer wall surface 21c of the long wall portion 21 as it approaches the center portion of the inner wall surface 21a . Therefore, the width W13 of the center portion of the bottom wall surface 21b of the long wall portion 21 is narrower than the width W12 of the bottom wall surface 21b of the long wall portion 21 on the short wall portion 22 side. In this way, the average width W1 of the second embodiment is the average value of the thicknesses of the respective portions of the long wall portion 22 . Also, in the second embodiment, the thickness W24 of the bottom wall surface 22b of the short wall portion 22 is constant, so that W2=W24. Furthermore, the average width W2 is larger than the average width W1.

Unlike the above-described embodiment, when the inner wall surface 21a is not parallel to the outer wall surface 21c as in the second embodiment, the boundary 15 between the long wall portion 21 and the short wall portion 22 can be determined by the following method. First, as shown in FIG. 6 , a rectangle C in contact with the inner wall portion of the nozzle 18 is drawn as described below, and each vertex of the rectangle C becomes the boundary 15 . In the rectangle C, when the area of the figure enclosed by the first side C1 and the inner wall of the rectangle C is D1, the area of the figure enclosed by the second side C2 opposite the first side C1 and the inner wall is defined as D1. Let the area be D2, and let the area of the figure surrounded by the third side C3 adjacent to the first side C1 and the inner wall be D3, and the area of the figure surrounded by the fourth side C4 facing the third side C3 and the inner wall shall be When the area of the figure is set to D4, it is the shape of D1+D2=D3+D4.

Also in the second embodiment, since the average width W2 is larger than the average width W1 , the molten glass 2 can be effectively stretched along the longitudinal direction of the flat cross section of the nozzle hole 16 by the nozzle 18 . As a result, as shown in FIG. 5, it becomes possible to manufacture glass fiber 2f with a high aspect ratio.

Next, a third embodiment different from the above-mentioned two embodiments will be described. The configuration other than the nozzle 8 is the same as that of the above-described embodiment. Therefore, only the differences from the above-described embodiment will be described.

As shown in FIG. 7 , the nozzle 28 of the third embodiment has a pair of long wall portions 31 and 31 and a pair of short wall portions 32 and 32 . The pair of long wall portions 31 and 31 is provided with a notch portion 33 that opens toward the outflow port 6b side, respectively. The shape of the cutout portion 33 is the same as that of the above-described embodiment. Moreover, the width W3 of the long wall portion 31 and the short wall portion 32 in plan view is constant. The long wall portion 31 has a bottom wall surface 31b continuous with the inner wall surface 31a.

As shown in FIG. 8 , the short wall portion 32 has an inner wall surface 32a and a bottom wall surface T that is continuous with the inner wall surface 32a. The bottom wall surface T has a vertical bottom wall surface 32b and an inclined bottom wall surface 32c. The vertical bottom wall surface 32b is perpendicular to the inner wall surface 32a; Furthermore, in the third embodiment, the thickness of the short wall portion 32 is constant as in the second embodiment. As shown in FIG. 8, the width|variety of the vertical bottom wall surface 32b is L2, and the width|variety of the inclined bottom wall surface 32c is L1. Here, the average width W2 of the bottom wall surface T is (L1+L2).

By providing the inclined bottom wall surface 32c in this way, the average width W2 of the bottom wall surface T is larger than that of W3 (L1 -L3). The relationship between L1 and L3, because L1=L3/cosθ, for example, when θ=55°, L1=1.74×L3.

Also in the third embodiment, since the average width W2 (W3+1.74L3) is increased by 1.74L3 from the average width W1 (W3), the molten glass 2 can be directed along the long axis of the flat cross-section of the nozzle hole 26 by the nozzle 28 direction is effectively stretched. As a result, as shown in FIG. 5, it becomes possible to manufacture glass fiber 2f with a high aspect ratio.

2: molten glass 2f: Profiled glass fiber 6: Nozzle hole 6a: Inflow port 6b: Outlet 8: Nozzle for special-shaped section glass fiber 11: Long Wall 11b: Bottom wall 12: Short Wall 12b: Bottom wall W1: width W2: width

FIG. 1 is a cross-sectional view schematically showing an apparatus for producing a glass fiber with a special-shaped cross-section provided with a nozzle for a glass fiber with a special-shaped cross-section according to the present embodiment. [ Fig. 2] Fig. 2 is a cross-sectional view schematically showing the periphery of the nozzle for glass fiber with a special-shaped cross-section of the present embodiment. [ Fig. 3] Fig. 3 is a bottom view schematically showing the periphery of the nozzle for glass fiber with a special-shaped cross-section of the present embodiment. Fig. 4 is a side view showing the nozzle for glass fibers with an irregular cross section according to the present embodiment, Fig. 4(a) is a side view of the nozzle for glass fibers with an irregular cross section viewed from the long wall side, and Fig. 4(b) is a nozzle for glass fibers with an irregular cross section. The cross-sectional view of the nozzle, Fig. 4(c) is a bottom view of the nozzle for glass fiber with a special-shaped cross-section. [Fig. 5] is a cross-sectional view showing a glass fiber with an irregular cross-section. 6] It is a bottom view of the nozzle for glass fibers with an irregular cross section of the second embodiment. [ Fig. 7 ] is a side view of the nozzle for glass fibers with a special-shaped cross-section, which shows the third embodiment, Fig. 7(a) is a side view of the nozzle for glass fibers with a special-shaped cross-section viewed from the long wall side, and Fig. 7(b) is a glass fiber with a special-shaped cross-section. Using the bottom view of the nozzle, Fig. 7(c) is a sectional view taken along the line 4b-4b of Fig. 7(b). [Fig. 8] It is an enlarged view of part A of Fig. 7(c).

6: Nozzle hole

6a: Inflow port

6b: Outlet

6x: axis

8: Nozzle for special-shaped section glass fiber

11: Long Wall

11a: inner wall surface

11b: Bottom wall

12: Short Wall

12a: inner wall surface

12b: Bottom wall

13: Notch part

15: Boundaries

W1,W11,W21,W22,W23: Width

Z: left and right direction

Claims (4)

A nozzle for glass fiber with a special-shaped cross-section is provided with a nozzle hole having an inflow port and an outflow port for molten glass and having a flat cross-section, the nozzle hole is composed of: a pair of short and long-diameter opposite to each other in the long-diameter direction of the flat cross-section. A pair of long wall portions facing each other in the short diameter direction of the flat cross-section, the nozzle for glass fiber with special-shaped cross-section is used for producing glass fiber with special-shaped cross-section from molten glass flowing out from the nozzle hole, The average width of the bottom wall surface of the short wall portion is wider than the average width of the bottom wall surface of the long wall portion. The nozzle for glass fiber with special-shaped cross-section according to claim 1, wherein, The average width of the bottom wall surface of the short wall portion is 1.5 times or more the average width of the bottom wall surface of the long wall portion. The nozzle for glass fiber with a profiled profile according to claim 1 or 2, wherein, The area of the bottom wall of the short wall portion is larger than the area of the bottom wall of the long wall portion. A method for producing a special-shaped glass fiber, which is a method for producing a special-shaped glass fiber from a molten glass flowing out of the nozzle hole using a nozzle for the special-shaped glass fiber provided with a nozzle hole, The nozzle hole has an inflow port and an outflow port of the molten glass and has a flat cross section, and includes a pair of short wall portions facing each other in the longitudinal direction of the flat cross section, and a short wall section in the flat cross section. A pair of long walls facing each other in the radial direction, The average width of the bottom wall surface of the short wall portion is wider than the average width of the bottom wall surface of the long wall portion.

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