Bushing and method for manufacturing glass fiber

Abstract

To provide a busing capable of stably drawing a molten glass from a nozzle arranged in a miniaturized base plate, and a manufacturing method of a glass fiber.SOLUTION: A first nozzle N1 and a second nozzle N2 of a bushing 11 have a configuration of an inner diameter of a nozzle hole D1[mm], a passage length of the nozzle Lt[mm], a cross-sectional area of the nozzle hole A1[mm2], and a cross-sectional area of a nozzle wall A2[mm2] each. An interval dimension between the first nozzles N1 in a row and an interval dimension between the second nozzles N2 in a row are defined as L1[mm]. An interval dimension between the first nozzle line R1 and the second nozzle line R2 is defined as an interval dimension L2[mm]. The bushing satisfies equations (1) - (6) below. y1≤Y≤y2 (1), y1=4 / 3 × X+3 (2), y2=4 / 3 × X+8 (3), X=D14 / Lt (4), Y=A3-(A1+A2) (5), and A3=L1 × L2 (6).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a bushing and a method for manufacturing a glass fiber. [Background technology]

[0002] As disclosed in Patent Document 1, a bushing including a base plate and a plurality of nozzles provided on the bottom surface of the base plate is used in the production of glass fibers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-231926 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned bushing, in order to reduce the amount of material used for the base plate, the adjacent nozzles have been arranged closer to each other to reduce the size of the base plate. However, in such a compact bushing, the molten glass flowing out of the nozzles is likely to adhere to the gaps between the adjacent nozzles. If the molten glass adheres to the gaps between the adjacent nozzles, it becomes difficult to stably draw the molten glass from the nozzle, and for example, the glass filament is likely to break.

[0005] An object of the present invention is to provide a bushing and a method for producing glass fibers that enable molten glass to be stably drawn from a nozzle provided on a miniaturized base plate. [Means for solving the problem]

[0006] The bushing that solves the above problem is a bushing having a base plate and a nozzle group provided on a bottom surface of the base plate, the nozzle group including a first nozzle row in which a plurality of first nozzles are arranged, and a second nozzle row in which a plurality of second nozzles are arranged and disposed adjacent to the first nozzle row, the first nozzles and the second nozzles each having an inner diameter D1 [mm] of a nozzle hole, a flow path length Lt [mm] of the nozzle, a cross-sectional area A1 [mm 2 ], and the cross-sectional area of ​​the nozzle wall A2 [mm 2 [ ] configuration, and when the distance between the centers of adjacent first nozzles in the first nozzle row and the distance between the centers of adjacent second nozzles in the second nozzle row are defined as the intra-row distance L1 [mm], and the distance between the center of the first nozzle row in the row width direction and the center of the second nozzle row in the row width direction is defined as the inter-row distance L2 [mm], the following formulas (1) to (6) are satisfied.

[0007] y1≦Y≦y2 (1) y1 = 4 / 3 × X + 3 (2) y2 = 4 / 3 × X + 8 (3) X=D1 4 / Lt···(4) Y = A3 - (A1 + A2) (5) A3 = L1 × L2 (6) According to this configuration, since Y is y1 or more, it is possible to appropriately secure a space around the nozzle in accordance with the flow rate of the molten glass flowing out of the nozzle. This makes it possible to prevent the molten glass flowing out of the nozzle from adhering to the gap between adjacent nozzles. Furthermore, since Y is y2 or less, it is possible to prevent the space around the nozzle from becoming excessively large compared to the flow rate of the molten glass flowing out of the nozzle, and to prevent the manufacturing cost of the bushing from increasing.

[0008] It is preferable that the bushing further satisfies the following formula (7). 0.2≦X≦3.0 (7) According to this configuration, the molten glass can be drawn out from the nozzle more stably.

[0009] In the above bushing, it is preferable that the average value of the arithmetic mean roughness Ra of the inner peripheral surfaces of the nozzle holes of the first nozzle and the second nozzle is 2 μm or less. With this configuration, the outflow speed of the molten glass flowing out of the nozzles can be made more uniform. This makes it possible to further prevent the molten glass flowing out of the nozzles from adhering to the gap between adjacent nozzles.

[0010] A method for producing glass fibers includes supplying molten glass to a bushing, drawing out a plurality of glass filaments from the bushing, and bundling the plurality of glass filaments to produce glass fibers, the bushing having a base plate and a nozzle group provided on a bottom surface of the base plate, the nozzle group including a first nozzle row in which a plurality of first nozzles are arranged, and a second nozzle row in which a plurality of second nozzles are arranged and disposed adjacent to the first nozzle row, the first nozzle and the second nozzle each having an inner diameter D1 [mm] of a nozzle hole, a flow path length Lt [mm] of a nozzle, a cross-sectional area A1 [mm 2 ], and the cross-sectional area of ​​the nozzle wall A2 [mm 2 ], and when the distance between the centers of adjacent first nozzles in the first nozzle row and the distance between the centers of adjacent second nozzles in the second nozzle row are defined as the intra-row distance L1 [mm], and the distance between the center of the first nozzle row in the row width direction and the center of the second nozzle row in the row width direction is defined as the inter-row distance L2 [mm], the above formulas (1) to (6) are satisfied. Effect of the Invention

[0011] According to the present invention, it is possible to stably draw molten glass from a nozzle provided on a miniaturized base plate. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing a glass fiber manufacturing apparatus according to an embodiment. [Diagram 2] FIG. 4 is a bottom view showing a portion of the bushing. [Diagram 3] FIG. 3 is a partial cross-sectional view taken along line 3-3 in FIG. 2. [Figure 4] 1 is a graph showing the relationship between parameters relating to nozzle dimensions and parameters relating to nozzle arrangement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of a bushing and a method for manufacturing glass fiber will be described with reference to the drawings. As shown in FIG. 1, a bushing 11 is used for producing glass fibers (glass strands GS). The glass fiber production apparatus includes the bushing 11, an applicator 12 that applies a bundling agent to a large number of glass filaments GF drawn out from the bushing 11, and a gathering shoe 13 that gathers the large number of glass filaments GF to which the bundling agent has been applied. The large number of glass filaments GF are gathered by the gathering shoe 13 to obtain a glass strand GS. The glass fiber production apparatus includes a collet 14 that winds up the glass strand GS, and a cake CA is obtained by winding the glass strand GS around the collet 14. Although not shown in the figure, the glass fiber production apparatus includes a traverse that moves the glass strand GS back and forth.

[0014] The bushing 11 includes a bushing body 11a to which the molten glass MG is supplied, and a base plate 11b provided at the bottom of the bushing body 11a. Although not shown in the figure, the bushing body 11a includes a supply port through which the molten glass MG is supplied, a screen for preventing foreign matter from accumulating on the base plate 11b, a terminal for resistance heating, and the like.

[0015] The bushing 11 includes a nozzle group provided on the bottom surface 11b1 of the base plate 11b. Molten glass MG is supplied to each nozzle N, and glass filaments GF are drawn out. The number of nozzles is preferably 800 to 10,000, and more preferably 2,000 to 8,000. Note that the nozzle group of the bushing 11 is shown in a simplified form in the drawings.

[0016] As shown in Fig. 2, the nozzle group of the bushing 11 includes a first nozzle row R1 in which a plurality of first nozzles N1 are arranged, and a second nozzle row R2 in which a plurality of second nozzles N2 are arranged. The second nozzle row R2 is arranged adjacent to the first nozzle row R1. More specifically, the arrangement direction of the plurality of first nozzles N1 and the plurality of second nozzles N2 is a horizontal direction along the Y-axis direction in Fig. 2. The first nozzle row R1 and the second nozzle row R2 are arranged adjacent to each other in a horizontal direction along the X-axis direction perpendicular to the Y-axis direction in Fig. 2.

[0017] As shown in FIGS. 2 and 3, the first nozzle N1 and the second nozzle N2 have an inner diameter D1 [mm] of the nozzle hole, a flow passage length Lt [mm] of the nozzle, and a cross-sectional area A1 [mm 2 ], and the cross-sectional area of ​​the nozzle wall A2 [mm 2 The first nozzle N1 and the second nozzle N2 each have a flow path that extends vertically along the Z-axis direction in FIGS.

[0018] 3, the nozzle flow passage length Lt is the length from the inner bottom surface 11b2 of the bushing 11 to the tip of the nozzle N. In other words, the nozzle flow passage length Lt [mm] is the sum of the thickness dimension Lt1 [mm] of the base plate 11b and the length dimension Lt2 [mm] from the bottom surface 11b1 of the base plate 11b to the tip of the nozzle N. Cross-sectional area A1 [mm 2 ] and the cross-sectional area of ​​the nozzle wall A2 [mm 22, is the cross-sectional area in the transverse section of the nozzle N. In this embodiment, the cross-sectional area of ​​the nozzle hole is A1 over the entire flow path length Lt, and the cross-sectional area of ​​the nozzle wall is A2 over the entire length of the nozzle N. The cross-sectional shape of the nozzle hole is circular, and a glass filament GF having a circular cross section is drawn out from this nozzle hole.

[0019] The bushing 11 satisfies the following formulas (1) to (6). y1≦Y≦y2 (1) y1 = 4 / 3 × X + 3 (2) y2 = 4 / 3 × X + 8 (3) X=D1 4 / Lt···(4) Y = A3 - (A1 + A2) (5) A3 = L1 × L2 (6) Here, the distance between the centers of adjacent first nozzles N1 in the first nozzle row R1 and the distance between the centers of adjacent second nozzles N2 in the second nozzle row R2 are defined as the intra-row distance L1 [mm]. The distance between the center in the row width direction of the first nozzle row R1 and the center in the row width direction of the second nozzle row R2 are defined as the inter-row distance L2 [mm]. Note that a straight line passing through the center in the row width direction of the first nozzle row R1 and a straight line passing through the center in the row width direction of the second nozzle row R2 are parallel to each other.

[0020] The above formula (4) is a relational expression for determining a numerical value representing the degree of the outflow speed of the molten glass MG flowing out of the nozzle N. The larger the inner diameter D1 of the nozzle hole, the faster the outflow speed of the molten glass MG. Also, the shorter the nozzle flow path length Lt, the faster the outflow speed of the molten glass MG.

[0021] The above formula (5) is a relational expression for finding a value expressing the size of the space around one nozzle N. In detail, the above formula (6) makes it possible to find the nozzle arrangement area A3, which is the area consisting of one nozzle N and the space around the nozzle N, in a bottom view of the bushing 11, as shown by the matte pattern in Fig. 2. The above formula (5) makes it possible to find the area of ​​the space around one nozzle N by subtracting the cross-sectional area A1 of the nozzle hole and the cross-sectional area A2 of the nozzle wall from the nozzle arrangement area A3.

[0022] The inner diameter D1 [mm] of the nozzle hole is, for example, preferably in the range of 0.5 mm to 3.0 mm, more preferably in the range of 0.8 mm to 2.0 mm. The flow path length Lt [mm] of the nozzle is preferably in the range of 1.5 mm to 8.0 mm, more preferably in the range of 2.5 mm to 6.0 mm. The cross-sectional area A1 [mm 2 ] is 0.2 mm 2 Above 7.0mm 2 It is preferable that the thickness is within the range of 0.5 mm or less, and more preferably within the range of 0.5 mm or less. 2 Above 5.0mm 2 The cross-sectional area of ​​the nozzle wall A2 [mm 2 ] is 0.6mm 2 More than 4.9mm 2 It is preferable that the thickness is within the range of 0.8 mm or less. 2 Above 3.5mm 2 It is within the following range.

[0023] From the viewpoint of drawing the molten glass MG from the nozzle N more stably, for example, the bushing 11 preferably further satisfies the following formula (7). 0.2≦X≦3.0 (7) The average value of the arithmetic mean roughness Ra on the inner peripheral surface Ns of the nozzle hole of the first nozzle N1 and the second nozzle N2 is preferably 2 μm or less, more preferably 0.1 μm or more, and further preferably within the range of 0.3 μm or more and 1.5 μm or less.

[0024] The average value of the arithmetic mean roughness Ra of the inner peripheral surface Ns of the nozzle hole can be adjusted by the shape of the drill used to drill the nozzle hole and the vibration of the drill. The average value of the arithmetic mean roughness Ra of the inner peripheral surface Ns of the nozzle hole can also be adjusted by contacting the inner peripheral surface Ns of the nozzle hole with a drill or by annealing the surface.

[0025] The average value of the arithmetic mean roughness Ra is a value in an unused state before the molten glass MG is distributed. The average value of the arithmetic mean roughness Ra can be measured as follows. First, a plurality of nozzles N are manufactured under the same manufacturing conditions, and then a nozzle N to be measured is extracted as a sample from among the plurality of nozzles N. Next, the extracted sample is cut along the direction in which the axis of the nozzle hole extends (the direction corresponding to the Z-axis direction in the bushing 11). Next, the arithmetic mean roughness Ra of the inner peripheral surface Ns of the nozzle hole is measured along the direction in which the axis of the hole extends in accordance with JIS B0601:2001.

[0026] The arithmetic mean roughness Ra is measured using a Surfcorder (manufactured by Kosaka Laboratory Co., Ltd., product name: ET4000) at a measurement distance of 1 mm. The arithmetic mean roughness Ra is measured at six mutually different positions.

[0027] Next, the average of the arithmetic mean roughness Ra measured at each of the six locations is calculated to obtain the average arithmetic mean roughness Ra of the inner circumferential surface Ns. For nozzles N other than the sample for which the arithmetic mean roughness Ra was measured, it is assumed that they have the same average value as the average value of the arithmetic mean roughness Ra of the sample.

[0028] The bushing 11 of the present embodiment further includes a cooling member 15 provided on the bottom surface 11b1 of the base plate 11b. The cooling member 15 cools the molten glass MG drawn out from the nozzle N. Examples of the cooling member 15 include a cooling fin and a cooling pipe having a flow path therein through which a cooling medium flows.

[0029] The cooling member 15 has a longitudinal direction and is arranged to extend along the first nozzle row R1 and the second nozzle row R2. The cooling member 15 is composed of a plurality of cooling members 15 arranged at a predetermined interval. In the bushing 11 of the present embodiment, two nozzle rows consisting of the first nozzle row R1 and the second nozzle row R2 are arranged between adjacent cooling members 15, but three or more nozzle rows may be arranged between adjacent cooling members 15.

[0030] Examples of materials for the bushing body 11a, the base plate 11b, the nozzle N, and the cooling member 15 include precious metals and precious metal alloys. Precious metals are gold, silver, platinum, palladium, rhodium, iridium, ruthenium, and osmium. From the viewpoint of increasing durability, the materials for the bushing body 11a, the base plate 11b, the nozzle N, and the cooling member 15 are preferably platinum or a platinum alloy. Examples of platinum alloys include a platinum-rhodium alloy.

[0031] Next, a method for producing glass fibers will be described. In the method for producing glass fibers, molten glass MG is supplied to the above-mentioned bushing 11, a plurality of glass filaments GF are drawn out from the bushing 11, and then the plurality of glass filaments GF are bundled together to produce a glass strand GS.

[0032] The viscosity of the molten glass MG at the forming temperature for forming the glass filament GF is 10 2.0 ~10 3.5 It is preferable that the viscosity is in the range of 10 dPa·s, and more preferably, 10 2.5 ~10 3.3 The viscosity of the molten glass MG is in the range of dPa·s. Here, the viscosity of the molten glass MG refers to the viscosity of the molten glass at the position where it flows into the nozzle N.

[0033] The form of the glass fiber can be, for example, a cake CA in which a glass strand GS is wound. The glass strand GS can be used, for example, as chopped strands cut to a predetermined length, milled fibers, rovings, yarns, mats, cloths, tapes, or woven fabrics. Applications of the glass fiber can be, for example, for vehicles, electronic materials, building materials, civil engineering, aircraft-related applications, shipbuilding, logistics, industrial machinery, and daily necessities.

[0034] Next, the operation and effects of this embodiment will be described. (1) The faster the flow rate of the molten glass MG flowing out of the nozzle N is, and the narrower the space around the nozzle N is, the more likely the molten glass MG flowing out of the nozzle N will adhere to the gap between adjacent nozzles N. Here, the bushing 11 of this embodiment satisfies the above formulas (1) to (6). That is, in the bushing 11 of this embodiment, Y is y1 or more, so that the space around the nozzle N can be suitably secured in accordance with the flow rate of the molten glass MG flowing out of the nozzle N. This makes it possible to prevent the molten glass MG flowing out of the nozzle N from adhering to the gap between adjacent nozzles N. In addition, in the bushing 11 of this embodiment, Y is y2 or less, so that it is possible to prevent the space around the nozzle N from becoming excessively wide relative to the flow rate of the molten glass MG flowing out of the nozzle N, and to prevent the manufacturing cost of the bushing 11 from increasing. Therefore, it is possible to stably draw out the molten glass MG from the nozzle N provided on the miniaturized base plate 11b. This makes it possible to prevent, for example, the breakage of the glass filament GF from occurring.

[0035] (2) It is preferable that the bushing 11 further satisfies the above formula (7). In this case, the molten glass MG can be drawn out from the nozzle N more stably. (3) In the bushing 11, the average value of the arithmetic mean roughness Ra of the inner peripheral surface Ns of the nozzle hole of the first nozzle N1 and the second nozzle N2 is preferably 2 μm or less. In this case, the outflow speed of the molten glass MG flowing out of the nozzle N can be made more uniform. This makes it possible to further prevent the molten glass MG flowing out of the nozzle N from adhering to the gap between adjacent nozzles N. Therefore, it becomes possible to more stably draw out the molten glass MG from the nozzle N provided on the miniaturized base plate 11b.

[0036] (Example of change) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0037] The cooling member 15 of the bushing 11 may be omitted. In the bushing 11, the inner diameters of the nozzle holes of the multiple first nozzles N1 and the multiple second nozzles N2 may be the same or different. When the inner diameters of the nozzle holes of the nozzles N are different from each other, the average value of the inner diameters of the nozzle holes can be set as the inner diameter D1 [mm] of the nozzle hole in the above formula (4).

[0038] In the bushing 11, when Y in formula (1) is y2 or less, Y may be further set to y2a or less in the following formula (8), or may be set to y2b or less in the following formula (9).

[0039] y2a=4 / 3×X+7 (8) y2b=4 / 3×X+5 (9) In the bushing 11, the flow passage lengths of the multiple first nozzles N1 and the multiple second nozzles N2 may be the same or different. When the flow passage lengths of the nozzles N are different from each other, the average value of the flow passage lengths of the nozzles N can be set as the nozzle flow passage length Lt [mm] in the above formula (4).

[0040] In the bushing 11, the cross-sectional areas of the nozzle holes of the multiple first nozzles N1 and the multiple second nozzles N2 may be the same as each other or may be different. When the cross-sectional areas of the nozzle holes of the nozzles N are different from each other, the average value of the cross-sectional areas of the nozzle holes is calculated by dividing the cross-sectional area A1 [mm 2 ] can be used.

[0041] In the bushing 11, the cross-sectional areas of the nozzle walls of the multiple first nozzles N1 and the multiple second nozzles N2 may be the same or different. When the cross-sectional areas of the nozzle walls of the nozzles N are different from each other, the average value of the cross-sectional areas of the nozzle walls is calculated by dividing the cross-sectional area A2 [mm 2 ] can be used.

[0042] The spacing between the centers of the first nozzles N1 may be the same or different. When the spacing between the centers of the first nozzles N1 is different, the spacing L1 [mm] within the row in the above formula (6) can be calculated as the average value of the spacing between the centers of the first nozzles N1 and the spacing between the centers of the second nozzles N2.

[0043] The spacing between the centers of the second nozzles N2 may be the same or different. When the spacing between the centers of the second nozzles N2 is different, the spacing between the centers of the second nozzles N2 may be calculated as the average spacing between the centers of the second nozzles N2 and the average spacing between the centers of the first nozzles N1, and the spacing between the centers of the second nozzles N2 may be calculated as the spacing L1 [mm] in the row in the above formula (6).

[0044] The average value of the spacing between the centers of the first nozzles N1 and the average value of the spacing between the centers of the second nozzles N2 may be the same or different. When the average value of the spacing between the centers of the first nozzles N1 and the average value of the spacing between the centers of the second nozzles N2 are different, the average value calculated from the spacing between the centers of the first nozzles N1 and the spacing between the centers of the second nozzles N2 can be used as the spacing L1 [mm] within the row in the above formula (6).

[0045] In the bushing 11 of the above embodiment, the first nozzle N1 and the second nozzle N2 are arranged such that the center of the first nozzle N1 and the center of the second nozzle N2 are located on a straight line perpendicular to the arrangement direction of the first nozzle N1 and the second nozzle N2 in a bottom view of the bushing 11. This arrangement is not limited to the above, and the first nozzle N1 and the second nozzle N2 may be arranged such that either the center of the first nozzle N1 or the center of the second nozzle N2 is shifted from the straight line perpendicular to the arrangement direction of the first nozzle N1 and the second nozzle N2 in a bottom view of the bushing 11.

[0046] In the first nozzle row R1 of the bushing 11 in the above embodiment, the first nozzles N1 are arranged such that the centers of the first nozzles N1 are located on a single straight line when viewed from the bottom of the bushing 11. This arrangement is not limited to the above, and if it is not possible to position the centers of all the first nozzles N1 on a single straight line in the first nozzle row R1, the straight line may be set so that the sum of the distances between the straight line and the centers of the first nozzles N1 is minimized.

[0047] In the second nozzle row R2 of the bushing 11 in the above embodiment, the second nozzles N2 are arranged such that the centers of the second nozzles N2 are located on a single straight line when viewed from the bottom of the bushing 11. This arrangement is not limited to the above, and if the centers of all the second nozzles N2 cannot be located on a single straight line in the second nozzle row R2, the straight line may be set so that the sum of the distances between the straight line and the centers of the second nozzles N2 is minimized.

[0048] In the bushing 11 of the above embodiment, the line passing through the center in the row width direction of the first nozzle row R1 and the line passing through the center in the row width direction of the second nozzle row R2 are parallel, but they do not have to be parallel. However, in the bushing 11, it is necessary that the line passing through the center in the row width direction of the first nozzle row R1 and the line passing through the center in the row width direction of the second nozzle row R2 do not intersect. In this case, the average value of the distance between the line passing through the center in the row width direction of the first nozzle row R1 and the line passing through the center in the row width direction of the second nozzle row R2 is set to the distance between the rows L2 [mm].

[0049] Next, examples and comparative examples will be described. (Examples 1 to 50) In Examples 1 to 50, glass fibers were produced using bushings having the values ​​of X and Y shown in Tables 1 and 2. The number of nozzles in the bushing was 100, and the average value of the arithmetic mean roughness Ra on the inner circumferential surface of the nozzle holes was 1.5 μm. The viscosity of the molten glass at the forming temperature for forming the glass filaments was 10 3.0 The glass filament forming speed is in the range of 800 [m / min] or more and 3000 [m / min] or less.

[0050] (Comparative Examples 1 to 16) In Comparative Examples 1 to 16, glass fibers were produced in the same manner as in Examples 1 to 50, except that bushings having the values ​​of X and Y shown in Table 3 were used.

[0051] (Glass fiber productivity) Glass strands were produced continuously for 30 days using the bushings of Examples 1 to 17 and the bushings of Comparative Examples 1 to 16. The productivity of glass fibers produced over 30 days was evaluated according to the following evaluation criteria. The evaluation results are shown in Tables 1 to 3.

[0052] If the average number of times the glass filament breaks is 10 times or less per day: (A) Productivity is high. If the average number of times the glass filament breaks is more than 10 times / day and less than 30 times / day: (B) Productivity is somewhat low.

[0053] If the average number of times the glass filament breaks exceeds 30 times per day: (C) Productivity is low. (Reduction in material usage) For each bushing, those for which Y in formula (1) is y2 or less were evaluated as having an effect of reducing the amount of material used in the base plate (○), and those for which Y in formula (1) is greater than y2 were evaluated as not having an effect of reducing the amount of material used in the base plate (×). The evaluation results are shown in Tables 1 to 3.

[0054] [Table 1]

[0055] [Table 2]

[0056] [Table 3] FIG. 4 shows a graph plotting the X and Y values ​​for the bushings of each example in Tables 1 to 3. In this graph, the bushings of Examples 1 to 50 are indicated with "◯" and the bushings of Comparative Examples 1 to 16 are indicated with "△". In addition, in this graph, the straight line of the above formula (2) is indicated with a solid line, and the straight line of the above formula (3) is indicated with a dashed line. From this graph, it can be seen that the bushings of Examples 1 to 50 have configurations that fall within the range represented by the above formula (1). On the other hand, it can be seen that the bushings of Comparative Examples 1 to 16 have configurations that fall outside the range represented by the above formula (1).

[0057] The bushings of Examples 1 to 50 were evaluated as having high glass fiber productivity. On the other hand, the bushings of Comparative Examples 2, 3, 6, 8, 10, 12, 13, and 15 were evaluated as having low glass fiber productivity. In the bushings of Comparative Examples 1, 4, 5, 7, 9, 11, 14, and 16, the space around the nozzle was excessively wide compared to the flow rate of the molten glass flowing out of the nozzle, so that the amount of material used for the base plate could not be suitably reduced. [Explanation of symbols]

[0058] 11…Bushing 11b…Base plate 11b1…Bottom surface A1: Cross-sectional area of ​​nozzle hole A2: Cross-sectional area of ​​nozzle wall A3: Nozzle layout area CA…Cake D1: Inner diameter of nozzle hole GF: Glass filament GS: Glass strand Lt: Nozzle flow passage length L1: Spacing dimension within a row L2: Spacing between rows MG: Molten glass N…Nozzle N1…Nozzle No. 1 N2: No. 2 nozzle Ns…Inner peripheral surface R1: First nozzle row R2: Second nozzle row

Claims

1. 1. A bushing for use in producing glass fibers, comprising a base plate and a group of nozzles provided on a bottom surface of the base plate, the bushing comprising: The nozzle group includes a first nozzle row in which a plurality of first nozzles are arranged; a second nozzle row in which a plurality of second nozzles are arranged, the second nozzle row being disposed adjacent to the first nozzle row; The first nozzle and the second nozzle each have an inner diameter D1 [mm] of a nozzle hole, a flow path length Lt [mm] of the nozzle, and a cross-sectional area A1 [mm ２ ], and the cross-sectional area A2 of the nozzle wall [mm ２ [0033] a distance between the centers of adjacent first nozzles in the first nozzle row and a distance between the centers of adjacent second nozzles in the second nozzle row are defined as an intra-row distance L1 [mm]; When the distance between the center of the first nozzle row in the row width direction and the center of the second nozzle row in the row width direction is L2 [mm], The following formulas (1) to (6): y1≦Y≦y2 (1) y1=4 / 3×X+3...(2) y2=4 / 3×X+8...(3) X=D1 ４ / Lt・・・(4) Y=A3-(A1+A2)...(5) A3=L1×L2...(6) Meet the bushing.

2. The following formula (7): 0.2≦X≦3.0 (7) The bushing of claim 1 further comprising:

3. 3. The bushing according to claim 1, wherein an average value of arithmetic mean roughness Ra of inner circumferential surfaces of the nozzle holes of the first nozzle and the second nozzle is 2 μm or less.

4. A method for producing a glass fiber, comprising: supplying molten glass to a bushing; drawing out a plurality of glass filaments from the bushing; and bundling the plurality of glass filaments to produce a glass fiber, the method comprising the steps of: The bushing includes a base plate and a nozzle group provided on a bottom surface of the base plate, The nozzle group includes a first nozzle row in which a plurality of first nozzles are arranged; a second nozzle row in which a plurality of second nozzles are arranged, the second nozzle row being disposed adjacent to the first nozzle row; The first nozzle and the second nozzle each have an inner diameter D1 [mm] of a nozzle hole, a flow path length Lt [mm] of the nozzle, and a cross-sectional area A1 [mm ２ ], and the cross-sectional area A2 of the nozzle wall [mm ２ [0033] a distance between the centers of adjacent first nozzles in the first nozzle row and a distance between the centers of adjacent second nozzles in the second nozzle row are defined as an intra-row distance L1 [mm]; When the distance between the center of the first nozzle row in the row width direction and the center of the second nozzle row in the row width direction is L2 [mm], The following formulas (1) to (6): y1≦Y≦y2 (1) y1=4 / 3×X+3...(2) y2=4 / 3×X+8...(3) X=D1 ４ / Lt・・・(4) Y=A3-(A1+A2)...(5) A3=L1×L2...(6) A method for manufacturing glass fibers that satisfies the above requirements.

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