TW202206386A - Nozzle for special-shaped section glass fiber, and manufacturing method of special-shaped section glass fiber - Google Patents

Abstract

Provided is a nozzle 8 for modified cross-section glass fibers, the nozzle 8 being provided with a nozzle hole 6 and being for manufacturing modified cross-section glass fibers 2f from molten glass 2 discharged from the nozzle hole 6, which is flat and has an inflow port 6a and an outflow port 6b for the molten glass 2, and a wall part enclosing the nozzle hole 6 having a pair of short wall parts 12 that face each other across the long diameter direction of the nozzle hole 6 and a pair of long wall parts 11 that face each other across the short diameter direction thereof, wherein: provided to each of the pair of short wall parts 12 is a slanted part 12aa, which is slanted relative to the axis 6x of the nozzle hole 6, at an end region T located at the end of the short wall part 12 that is toward the outflow port 6b.

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.

As one kind of glass fiber, a cross-sectional glass fiber with a flat profile is known (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. In the glass fiber with a special-shaped cross-section, each of a pair of short wall portions has an inclined portion inclined with respect to the axis of the nozzle hole in the end region of the end portion located on the outflow port side of the short wall portion.

According to the present nozzle, the end region has the inclined portion inclined with respect to the axis of the nozzle hole, and the contact area between the end region and the molten glass is enlarged compared to the conventional case where there is no inclined portion in the end region. Thereby, the ability to stretch the molten glass (the ability to stretch in the longitudinal direction of the flat cross section of the nozzle hole) is improved in the end region of the short wall portion, and the melting by the surface tension can be suppressed along with this. The glass deforms in such a way that the surface area becomes smaller. As a result, the produced profiled glass fiber can be formed with a high aspect ratio.

It is preferable that the nozzle for glass fibers with an irregular cross section of the present invention has an inclined surface which is inclined so as to be separated from the center side of the flat cross section of the nozzle hole as it goes from the inflow port side of the molten glass to the outflow port side. .

According to this configuration, the ability to draw the molten glass in the end region of the short-wall portion is further improved, and it becomes more advantageous in forming the glass fiber with a special profile at a high aspect ratio.

In the nozzle for glass fiber with an irregular cross section of the present invention, it is preferable that the short wall portion has a bottom wall surface connected to the inclined portion at the end region, and the long wall portion has a bottom wall surface at the end portion on the outflow port side. The length of the bottom wall surface of the long wall portion on the cross section orthogonal to the long diameter direction of the flat cross section, the length of the inclined portion and the bottom of the short wall portion on the cross section orthogonal to the short diameter direction of the flat cross section of the nozzle hole The sum of the lengths of the walls is longer.

When producing a glass fiber with an irregular cross-section, in addition to the inclined portion of the short-wall portion, the bottom wall surfaces of the short-wall portion and the long-wall portion are also in a state of being wetted by the molten glass. At this time, the inclined portion and the bottom wall surface stretch the molten glass. Furthermore, in order to increase the oblateness of the produced glass fiber with a special profile, the molten glass is drawn along the long diameter of the flat cross section of the nozzle hole rather than the short diameter direction of the flat cross section of the nozzle hole. Directional stretching is more favorable. Furthermore, according to this structure, the molten glass can be efficiently drawn along the longitudinal direction of the flat cross-section of the nozzle hole, 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 nozzle for glass fibers with a special-shaped cross section of the present invention is configured such that the inclined portion is constituted by a single inclined surface.

According to this structure, it becomes difficult for a molten glass to stay, and devitrification (devitrification) can be suppressed.

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 is opposite to a pair of long wall parts, and each of the pair of short wall parts has an inclination with respect to the axis of the nozzle hole in the end region of the end part located on the outflow port side of the short wall part. inclined 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 represented by "-" is the range included with the numerical value described before and after the "-" as 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 Fig. 4(a), (b), 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 notch portion 13 (the length in the direction of the axis 6x along the direction connecting the inflow port 6a and the outflow port 6b 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 . Also in this embodiment, the thickness of the short wall portion 12 (thickness in the longitudinal direction along the flat cross section of the nozzle hole 6 ) is greater than the thickness of the long wall portion 11 (the thickness in the short diameter direction along the flat cross section of the nozzle hole 6 ). thickness) is larger. Here, the flatness ratio (ratio of the long diameter and the short diameter) of the nozzle hole 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 where the slope of the inner wall surface changes from 0 with respect to the left-right direction in FIG. It is the long wall part 11 , and the part other than the slope 0 is the short wall part 12 .

As shown in FIGS. 4( b ) and 5 , each of the pair of short wall portions 12 , 12 has an end portion region T located at the end portion on the side of the outflow port 6 b of the pair, with respect to the nozzle hole 6 . The axis 6x is an inclined portion 12aa which is inclined. Specifically, the inclined portion 12aa is directed from the center side of the flat cross section of the nozzle hole 6 to the outside (the inner side in the longitudinal direction of the flat cross section of the nozzle hole 6 is directed from the inflow port 6a side to the outflow port 6b side). outside). Thereby, the inclined part 12aa located on one side of the pair of short wall parts 12 and 12 and the inclined part 12aa located on the other side are inclined in the directions opposite to each other. The two inclined portions 12aa, 12aa are each formed by a single inclined surface (inclined plane). The inclined portion 12aa is formed over the entire length of the short wall portion 12 along the short diameter direction of the flat cross section of the nozzle hole 6 (in FIG. 4( b ) and FIG. 5 , the direction perpendicular to the paper surface). The angle θ1 at which the inclined portion 12aa is inclined with respect to the line orthogonal to the axis 6x is not particularly limited, but is 55° in this embodiment. Moreover, as long as it is inclined with respect to the axis line 6x of the nozzle hole 6, the inclined part 12aa may be a curved surface. Further, the surface roughness of the inclined portion 12aa may be larger than the surface roughness of the inner wall surface 12a. Further, the angle θ1 at which the inclined portion 12aa is inclined with respect to the line orthogonal to the axis 6x is preferably 10° or more and 80° or less.

The short wall portion 12 has a bottom wall surface 12b connected to the inclined portion 12aa. Specifically, the inclined portion 12aa is connected to the bottom wall surface 12b on the outer side in the longitudinal direction of the nozzle hole 6 . In the present embodiment, the bottom wall surface 12b is a flat surface orthogonal to the axis 6x. Here, let the length of the inclined part 12aa be L1, and let the length of the bottom wall surface 12b be L2. In addition, "the length L1 of the inclined part 12aa and the length L2 of the bottom wall surface 12b" are the lengths in the cross section orthogonal to the short diameter direction of the flat cross section of the nozzle hole 6, respectively.

Thereby, the edge part area|region T of this embodiment becomes large compared with the case where there is no inclined part 12aa. More specifically, in the present embodiment, the approximate area of the end region T is a value obtained by multiplying the sum of the length L1 of the inclined portion 12aa and the length L2 of the bottom wall surface 12b by the circumference of the short wall portion 12 . The approximate area of the end region without the inclined portion 12aa is the value obtained by multiplying the sum of the length L2 of the bottom wall surface 12b and the length L3 of the virtual bottom wall surface by the circumference of the short wall portion 12 . The relationship between L1 and L3 is L1=L3/cos55°=1.74×L3. That is, the rough area of the end region T of the present embodiment is larger than the rough area of the conventional edge region without the inclined portion 12aa.

As shown in FIG. 6 , the long wall portion 11 has a bottom wall surface 11b. 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). Here, the length of the bottom wall surface 11b is L4. In addition, "the length of the bottom wall surface 11b" is the length in the cross section orthogonal to the longitudinal direction of the flat cross section of the nozzle hole 6. As shown in FIG. Also, the sum of the above-mentioned length L1 and length L2 is longer than the length L4. As a result, the area of the end region T of the short wall portion 12 is made larger than the area of the bottom wall surface 11b of the long wall portion 11 , and the molten glass 2 is more likely to follow the long diameter direction than the short diameter direction of the flat cross section of the nozzle hole 6 . stretched in the radial direction.

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.

According to the nozzle 8 described above, the end region T has the inclined portion 12aa inclined with respect to the axis 6x of the nozzle hole 6. Compared with the case where the end region T does not have the inclined portion 12aa, the difference between the end region T and the molten glass 2 is greater. The contact area is enlarged. Thereby, the ability of the short-wall portion 12 to stretch the molten glass 2 is improved, and along with this, the molten glass 2 can be prevented from being deformed so that the surface area becomes small due to surface tension. As a result, as shown in FIG. 7, 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, as shown in FIG. 8, the long wall part 11 may have the inclined part 11aa. The angle θ2 at which the inclined portion 11aa is inclined with respect to the line orthogonal to the axis 6x is preferably 10° or more and 80° or less. Furthermore, by setting θ1>θ2, the ability of the inner wall surface 11a of the long wall portion 11 to stretch the molten glass 2 does not become too large, and the reduction in the ellipticity of the glass fiber can be suppressed.

Furthermore, when the long wall portion 11 is provided with the inclined portion 11aa, the inclined portion 11aa is not provided on the center side of the long wall portion 11, and the inclined portion 11aa is provided only on both end sides of the long wall portion 11, whereby the long wall portion 11 is not provided with the inclined portion 11aa. The ability to stretch the molten glass 2 does not become too large, and it is possible to suppress the reduction of the ellipticity of the glass fiber. For example, as shown in FIG. 9 , the inclined portion 11aa is provided on the long wall portion 11 other than the upper bottom of the cutout portion 13 of the isosceles trapezoid, and the inclined portion 11aa is not provided at the upper bottom of the cutout portion 13, thereby suppressing the glass fiber Flat rate becomes smaller.

Furthermore, in the above-described embodiment, although the notch portion 13 is provided in each of the pair of long wall portions 11 and 11, the notch portion 13 is not necessarily provided, and it 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, a rectangle shape, and three consecutive perfect circles.

2: molten glass 2f: Profiled glass fiber 6: Nozzle hole 6a: Inflow port 6b: Outlet 6x: axis 8: Nozzle for special-shaped section glass fiber 11: Long Wall 11b: Bottom wall 12: Short Wall 12a: inner wall surface 12aa: inclined part 12b: Bottom wall L1: length L2: length L3: length T: end area

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 one of the nozzles in Fig. 3 . 4b-4b sectional view, Fig. 4(c) is a 4c-4c sectional view of Fig. 4(a). Fig. 5 is a cross-sectional view showing part A of Fig. 4(b) in an enlarged manner. [ Fig. 6] Fig. 6 is a cross-sectional view showing the periphery of the bottom wall surface of the long wall portion of the nozzle for glass fibers with a special-shaped cross-section of the present embodiment. [Fig. 7] is a cross-sectional view showing a glass fiber with an irregular cross-section. Fig. 8 is a modified example of the nozzle for glass fibers with an irregular cross-section, Fig. 8(a) is a side view of the nozzle for glass fibers with an irregular cross-section viewed from the short wall side, and Fig. 8(b) is one of the nozzles in Fig. 3 . 4b-4b sectional view, Fig. 8(c) is the 4d-4d sectional view of Fig. 8(a). [ Fig. 9] It is a bottom view of the nozzle for glass fiber with a special-shaped cross section of a modified example.

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

12aa: inclined part

12b: Bottom wall

13: Notch part

15: Boundaries

T: end area

Claims (6)

A nozzle for glass fiber with a special-shaped section is provided with an inflow port and an outflow port for molten glass and a nozzle hole with a flat cross section, The nozzle hole comprises: a pair of short wall portions facing each other in the longitudinal direction of the flat cross section, and a pair of long wall portions facing each other in the short diameter direction of the flat cross section, The special-shaped cross-section glass fiber nozzle is used for producing the special-shaped cross-section glass fiber from the molten glass flowing out from the nozzle hole, Each of the pair of short wall portions has an inclined portion inclined with respect to the axis of the nozzle hole in the end region of the end portion of the short wall portion on the side of the outflow port. The nozzle for glass fiber with special-shaped cross-section according to claim 1, wherein, The said inclined part has the inclined surface which inclines so that it may separate from the center side of the flat cross section of the said nozzle hole as it goes from the said inflow port side to the said outflow port side. The nozzle for glass fiber with a profiled profile according to claim 1 or 2, wherein, The short wall portion has a bottom wall surface connected to the inclined portion in the end region, The long wall portion has a bottom wall surface at the end portion on the outflow port side, The length of the inclined portion and the bottom wall surface of the short wall portion on the cross section orthogonal to the short diameter direction are compared with the length of the bottom wall surface of the long wall portion on the cross section orthogonal to the long diameter direction. The sum of the lengths is longer. The nozzle for glass fiber with a profiled profile according to claim 1 or 2, wherein, The said inclined part is comprised by a single inclined surface. The nozzle for glass fiber with a profiled profile according to claim 3, wherein, The said inclined part is comprised by a single inclined surface. 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, Each of the pair of short wall portions has an inclined portion inclined with respect to the axis of the nozzle hole in the end region of the end portion of the short wall portion on the side of the outflow port.

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