JP7262704B2 - Strand manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a strand by bundling a plurality of glass fibers.

BACKGROUND ART As a reinforcing material for glass fiber reinforced plastic moldings such as FRP and FRTP, a strand formed by bundling a large number of glass fibers is used. As for the glass fibers that make up the strands, modified cross-section glass fibers with non-circular cross-sections (flat cross-sections) such as elliptical or elliptical are used because they can be expected to have a high reinforcing effect and high dimensional stability for glass fiber-reinforced plastic molded products. Adopted.

Patent Literature 1 discloses an apparatus for manufacturing a strand by bundling glass fibers having a flat cross section. This manufacturing apparatus includes a molten glass reservoir, an applicator that applies a sizing agent to glass fibers, and a gathering shoe that bundles a plurality of glass fibers.

A bushing having a large number of nozzle holes is attached to the lower surface of the molten glass reservoir. After the molten glass flows out from each nozzle hole, it is cooled and solidified to form a large number of glass fibers. The nozzle hole of the bushing is formed in a non-circular shape such as an ellipse, an ellipse or a rectangle so that the glass fiber has a non-circular cross section such as an ellipse or an ellipse.

In order to produce a strand using the above-described production apparatus, the molten glass in the molten glass reservoir is discharged from a number of nozzle holes, cooled to form glass fibers, and then a sizing agent is applied to each glass fiber using an applicator. do. The glass fibers are then bundled into strands by a gathering shoe.

Japanese Patent No. 4462115

In the strand manufacturing method, when a large number of glass fibers formed by nozzle holes are bundled by a gathering shoe, each glass fiber is conveyed in an inclined state according to the positional relationship between each nozzle hole and the gathering shoe.

In this case, when the molten glass is pulled out from the nozzle hole, it may be pressed against the inner wall surface of the nozzle hole, and may not be formed into a desired irregular cross section, resulting in a defective shape of the glass fiber.

The present invention has been made in view of the above circumstances, and a technical object thereof is to reduce the shape defects of the glass fibers contained in the strand.

In order to solve the above problems, the present invention is to form glass fibers having an irregular cross section by discharging molten glass from a plurality of nozzles provided in a rectangular bushing, and converge the glass fibers with a gathering shoe. glass fibers formed by the outermost nozzle among the plurality of nozzles for discharging the molten glass when viewed from the longitudinal direction and the transverse direction of the bushing, and The angle formed by the horizontal line is characterized by being 70° or more and 89° or less.

According to this configuration, by setting the angle formed by the horizontal line and the glass fiber formed by the outermost nozzle out of the plurality of nozzles to be 70° or more, the molten glass is drawn out from the nozzle hole of the nozzle. At this time, it is possible to prevent the molten glass from being pressed against the inner wall surface of the nozzle hole, thereby preventing molding defects of the molten glass. This can reduce the shape defects of the glass fibers contained in the strand. Further, by setting the angle formed by the horizontal line and the glass fiber formed by the outermost nozzle out of the plurality of nozzles to 89° or less, it is possible to prevent the distance between the gathering shoe and the nozzle from becoming too long. . As a result, it is possible to suppress the size of the equipment and reduce the probability of thread breakage (breakage of glass fibers).

The number of nozzles may be 155 or more. As the number of nozzles increases, the number of glass fibers constituting the strand increases, and the shape defects of each glass fiber are more likely to occur. By applying the present invention, even in a strand containing 155 or more glass fibers, the shape defects of the glass fibers can be reduced as much as possible.

The method for manufacturing a strand according to the present invention includes a step of cooling the molten glass discharged from the nozzle by a cooling unit, the cooling unit forming a flow path through which a coolant flows along the longitudinal direction of the bushing. You may prepare. By arranging the flow path of the coolant along the longitudinal direction of the bushing, the molten glass discharged from each nozzle can be cooled appropriately.

The cooling part may be provided on the bushing and protrude downward from the lower end of the nozzle. Even in this case, by setting the straight line connecting the nozzle and the gathering shoe within the above angle range, the molten glass discharged from each nozzle is conveyed toward the gathering shoe without contacting the cooling section.

The nozzle may have an elongated nozzle hole along the longitudinal direction of the bushing. A glass fiber having a flattened cross section can be favorably formed by this nozzle hole.

According to the present invention, it is possible to reduce the shape defects of the glass fibers contained in the strand.

It is a schematic diagram showing a strand manufacturing apparatus. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1; It is a bottom view of a bushing. 4 is an image showing a cross section of a strand according to an example. It is an image which shows the cross section of the strand which concerns on a comparative example.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated, referring drawings. 1 to 3 show an embodiment of the method for manufacturing strands according to the present invention.

As shown in FIGS. 1 and 2, the strand manufacturing apparatus includes a glass melting furnace 1, a forehearth 2 connected to the glass melting furnace 1, a feeder 3 connected to the forehearth 2, and a sizing agent of glass fiber Gm. and an applicator 4 for applying the glass fiber Gm, and a gathering shoe 5 for concentrating the glass fibers Gm to form a strand Gs. Here, in the XYZ orthogonal coordinate system shown in FIG. 1, the X direction and the Y direction are horizontal directions, and the Z direction is the vertical direction (hereinafter the same in FIGS. 2 and 3).

Molten glass G is supplied from the glass melting furnace 1 through the forehearth 2 to the feeder 3 and stored in the feeder 3 . Although one feeder 3 is illustrated in FIG. 1 , a plurality of feeders 3 may be connected to the glass melting furnace 1 .

The bottom of the feeder 3 is configured with a rectangular bushing 6 . A plurality of nozzles 7 are provided at the bottom of the bushing 6 . A plurality of nozzles 7 are regularly arranged along the longitudinal direction LD and lateral direction SD of the bushing 6 . The number of nozzles 7 is preferably 155 or more, more preferably 200 or more and 3000 or less, but is not limited to this range.

In FIG. 1, of the plurality of nozzles 7 arranged along the longitudinal direction LD of the bushing 6, the glass fibers Gma, Gmb formed by the nozzles 7a, 7b located on the outermost side in the longitudinal direction LD of the bushing 6 and the horizontal line Angles (acute angles) θa and θb formed by HL are set to 70° or more and 89° or less when viewed from the longitudinal direction LD. Angles (acute angles) θa, θb formed by the glass fibers Gma, Gmb and the horizontal line HL when viewed from the longitudinal direction LD are preferably 73° or more, more preferably 75° or more. The angles (acute angles) θa, θb formed by the glass fibers Gma, Gmb and the horizontal line HL when viewed from the longitudinal direction LD are preferably 85° or less, more preferably 82° or less.

In the present embodiment, among the plurality of nozzles 7 arranged along the longitudinal direction LD of the bushing 6, the center C of the lower ends of the nozzles 7a and 7b located on the outermost side in the longitudinal direction LD and the gathering shoe. The angles (acute angles) θa and θb formed between the horizontal line HL and the straight line (one-dot chain line) connecting the point O at which the glass fibers Gma and Gmb contact the glass fibers Gma and Gmb are the angles (acute angles) θa and θb formed between the glass fibers Gma and Gmb and the horizontal line HL. coincides with θb.

Here, "viewed from the longitudinal direction" refers to a side view of the long side portion of the rectangular bushing 6, as shown in FIG. The term “outermost nozzle” refers to the outermost nozzle among the nozzles 7 that actually discharge the molten glass G when manufacturing the strand Gs. Therefore, when manufacturing the strand Gs, nozzles that do not discharge the molten glass G are not included in the outermost nozzles (the same applies hereinafter).

In FIG. 2, of the plurality of nozzles 7 arranged along the transverse direction SD of the bushing 6, the glass fibers Gmc, Gmd formed by the nozzles 7c, 7d located on the outermost side in the transverse direction SD and the horizontal line Angles (acute angles) θc and θd formed by HL are 70° or more and 89° or less when viewed from the lateral direction SD. Here, "when viewed from the short side" means when the short side portion of the rectangular bushing 6 is viewed from the side (see FIG. 2). Angles (acute angles) θc, θd formed between the glass fibers Gma, Gmb and the horizontal line HL when viewed from the lateral direction SD are preferably 73° or more, more preferably 75° or more. The angles (acute angles) θc, θd formed by the glass fibers Gma, Gmb and the horizontal line HL when viewed from the lateral direction SD are preferably 85° or less, more preferably 82° or less.

As shown in FIG. 2, when the applicator 4 contacts the glass fibers Gmc and Gmd, the angles (acute angles) formed by the glass fibers Gmc and Gmd and the horizontal line HL change from θc and θd to θe. This angle θe can be arbitrarily set according to the layout of the equipment.

As shown in FIG. 3, at the bottom of the bushing 6, due to the arrangement of the plurality of nozzles 7, a plurality of nozzle rows L are arranged at intervals in the transverse direction SD of the bushing 6 and parallel to the longitudinal direction LD. there is

As shown in FIG. 3, each nozzle 7 has a pair of long wall portions 8a, a pair of short wall portions 8b, and a nozzle hole 8c through which molten glass G is discharged.

The pair of long wall portions 8a face each other in the transverse direction SD of the bushing 6. As shown in FIG. Each long wall portion 8 a is formed along the longitudinal direction LD of the bushing 6 . The pair of short wall portions 8b face each other in the longitudinal direction LD of the bushing 6. As shown in FIG. Each short wall portion 8b is formed along the lateral direction SD of the bushing 6. As shown in FIG. The dimension of the short wall portion 8b in the lateral direction SD is shorter than the dimension of the long wall portion 8a in the longitudinal direction LD. A notch portion 8d is provided on the bottom surface of each short wall portion 8b.

The nozzle hole 8c is defined by a long wall portion 8a and a short wall portion 8b. The nozzle hole 8c is an opening formed in an elongated shape (oval, elliptical, etc.) along the longitudinal direction LD of the bushing 6. As shown in FIG. Both ends of the nozzle hole 8c in the longitudinal direction LD of the bushing 6 communicate with the external space of the nozzle 7 through respective notches 8d. The major axis direction of the nozzle hole 8 c coincides with the longitudinal direction LD of the bushing 6 , and the minor axis direction of the nozzle hole 8 c coincides with the lateral direction SD of the bushing 6 .

Comparing the portion corresponding to the long wall portion 8a and the portion corresponding to the short wall portion 8b of the inner wall surface of the nozzle hole 8c, the area of the portion corresponding to the long wall portion 8a is larger than the area of the portion corresponding to the short wall portion 8b. larger than the area of Therefore, when the molten glass G is pressed against the portion of the inner wall surface of the nozzle hole 8c corresponding to the long wall portion 8a, the shape defects of the glass fibers Gm are likely to occur. Therefore, when the nozzle holes 8c are arranged as shown in FIG. The angles (acute angles) θc, θd formed between the glass fibers Gmc, Gmd and the horizontal line HL when viewed from the direction SD are larger than the angles θa, θb formed between the glass fibers Gma, Gmb and the horizontal line HL when viewed from the longitudinal direction LD. A large value is desirable.

As shown in FIGS. 1 to 3, a cooling section 9 is provided near each nozzle 7 . Although the cooling part 9 is configured in a fin-like or plate-like shape integral with the bushing 6 , it is not limited to this shape, and may be a cooling pipe configured separately from the bushing 6 . A lower end portion 9b of the cooling portion 9 protrudes below the lower end portion of the nozzle 7 (nozzle hole 8c). Also, the cooling portion 9 is an elongated portion configured linearly along the longitudinal direction LD of the bushing 6 . The cooling part 9 includes a flow path 9 a through which the coolant flows along the longitudinal direction LD of the bushing 6 . The refrigerant is not particularly limited, and may be liquid or gas. Water is preferably used as the coolant, for example.

The cooling part 9 is arranged parallel to each nozzle row L between the nozzle rows L adjacent in the transverse direction SD of the bushing 6 . Thereby, the cooling part 9 faces the long wall part 8a of the nozzle 7, and the molten glass G flowing through the nozzle 7 across the long wall part 8a is cooled. Molten glass G flowing through the nozzle 7 is indirectly cooled via the long wall portion 8 a cooled by the cooling portion 9 . The cooling unit 9 also has a function of cooling the bushing 6 and the nozzle 7 to suppress their thermal deterioration and improve their durability.

At least a part of the bushing 6, the nozzle 7 and the cooling part 9 is made of platinum or a platinum alloy (for example, a platinum rhodium alloy).

The applicator 4 is configured as a roller that applies a sizing agent to the plurality of glass fibers Gm descending from the nozzle 7 . Binding agents include coupling agents, binding agents, lubricants, antistatic agents, antifoaming agents, and the like. For example, aminosilane and the like can be used as coupling agents, and acid-modified resins and the like can be used as binding agents. Examples of lubricants include fatty acid amides and quaternary ammonium salts, and examples of antistatic agents include polyether compounds, sulfonic acid compounds, betaine compounds, conductive polymers, and the like.

The applicator 4 is supported by a lifting device and can change its position in the vertical direction Z. That is, by changing the position of the applicator 4 in the vertical direction Z, the angles θc and θd can be adjusted.

The gathering shoe 5 forms a single strand Gs by bundling 155 or more, preferably 200 or more and 3000 or less glass fibers Gm. The gathering shoe 5 is configured to be reciprocally movable by traverse. Also, the gathering shoe 5 is supported by an elevating device and can change its position in the vertical direction Z. As shown in FIG. That is, by changing the position of the gathering shoe 5 in the vertical direction Z, the angles θa and θb can be adjusted.

A method of manufacturing the strand Gs using the manufacturing apparatus having the above configuration will be described below.

In this method, first, the molten glass G stored in the feeder 3 is drawn downward from a plurality of nozzles 7 provided on the bushing 6 . In this case, the molten glass G discharged from the nozzle 7 is flattened according to the shape of the nozzle hole 8c. The molten glass G is cooled by the cooling unit 9 to become glass fibers Gm. Alternatively, a sprayer may be arranged below the bushing 6 and the molten glass G may be cooled by cooling water sprayed from this sprayer.

The viscosity of the molten glass G is preferably set within the range of 10 ^2.0 to 10 ^3.5 dPa·s, more preferably 10 ^2.5 to 10 ^3.3 dPa·s.

The glass fibers Gm then descend further and pass through the applicator 4 . The roller of the applicator 4 contacts all the formed glass fibers Gm and applies a sizing agent to each glass fiber Gm.

The glass fibers Gm coated with a sizing agent pass through the gathering shoe 5 . As a result, the glass fiber Gm is spun into a single strand Gs. The strand Gs is wound around a collet provided below the gathering shoe 5 to form a cake. The strand Gs is stored in a cake state and pulled out of the cake as needed. The strand Gs is used as a chopped strand by being cut into a predetermined length.

According to the method for manufacturing the strands Gs according to the present embodiment described above, it is possible to reduce the shape defects of the glass fibers Gm for the following reasons. That is, when the angles θa to θd between the glass fibers Gma to Gmd formed by the outermost nozzles 7a to 7d and the horizontal line HL are less than 70°, the molten glass G is drawn out from the nozzles 7a to 7d. , the glass fibers Gma to Gmd are pressed against the inner wall surfaces of the nozzles 7a to 7d and are not molded into the desired flat shape, which causes the shape defects of the glass fibers Gma to Gmd. In this embodiment, by setting the angles θa to θd to 70° or more, it is possible to suppress the molten glass G from being pressed against the inner wall surface of the nozzle 7 . Therefore, the manufacturing method according to the present embodiment can reduce the shape defects of the glass fibers Gm contained in the strands Gs.

Further, when the angles θa to θd formed by the glass fibers Gma to Gmd formed by the outermost nozzles 7a to 7d and the horizontal line HL are 89° or less, an increase in the distance between the bushing 6 and the gathering shoe 5 is suppressed. can. As a result, it is possible to suppress an increase in the size of the equipment and to reduce the probability of occurrence of yarn breakage (breakage of the glass fibers Gma to Gmd) as much as possible.

In addition, the present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. Various modifications can be made to the present invention without departing from the gist of the present invention.

In the above-described embodiment, an example is shown in which a single gathering shoe 5 is used to bundle a plurality of glass fibers Gm, but the present invention is not limited to this configuration. In the present invention, multiple glass fibers may be bundled by multiple gathering shoes. In addition, a plurality of gathering shoes and a single gathering shoe have a two-stage configuration, and a plurality of strands collected by a plurality of gathering shoes in the first stage (upper stage) are collected by a single gathering shoe in the second stage (lower stage). It may be spun as a single strand.

In the above-described embodiment, the manufacturing apparatus capable of changing the positions of the applicator 4 and the gathering shoe 5 in the vertical direction Z was exemplified, but the present invention is not limited to this configuration. According to the present invention, the angles θa to θd of the glass fibers Gma to Gmd may be changed by changing the vertical position of the bushing 6, for example.

Although the longitudinal direction of the applicator 4 coincides with the longitudinal direction LD of the bushing 6 in the above embodiment, the present invention is not limited to this configuration. According to the present invention, the longitudinal direction of the applicator 4 may coincide with the lateral direction SD of the bushing 6 . In this case, by changing the position of the applicator 4 in the vertical direction Z, the angles θa and θb can be adjusted.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

The inventor conducted tests to confirm the effects of the present invention. In this test, the vertical position of the gathering shoe was changed in the manufacturing apparatus configured as described above to change the distance between the gathering shoe and the nozzle, thereby manufacturing strands according to Examples and Comparative Examples.

The strand according to the example was formed by 200 nozzles after setting the angle (θa, θb in FIG. 1) between the horizontal line and the glass fiber formed by the outermost nozzle in the longitudinal direction of the bushing to 78°. It was manufactured by bundling 200 glass fibers with a gathering shoe.

The strand according to the comparative example was manufactured by setting the angles (θa, θb) to 64° and then converging 200 glass fibers formed by 200 nozzles with a gathering shoe.

The strands according to Examples and Comparative Examples were cut, and each section was photographed with a microscope. FIG. 4 shows a cross-sectional image of the strand of the example, and FIG. 5 shows a cross-sectional image of the strand of the comparative example.

As a result of comparing the example and the comparative example, in the example, the cross sections of all the glass fibers were within the desired flatness ratio range, but in the comparative example, some of the glass fibers had a shape in the cross section. It was confirmed that a defect had occurred.

5 gathering shoe 6 bushing 7 nozzle 7a nozzle positioned outermost in the longitudinal direction of the bushing 7b nozzle positioned outermost in the longitudinal direction of the bushing 7c nozzle positioned outermost in the transverse direction of the bushing 7d transverse direction of the bushing Outermost nozzle 8c Nozzle hole 9 Cooling part 9a Flow path 9b Lower end of cooling part G Molten glass Gm Glass fiber Gma Glass fiber Gmb formed by the outermost nozzle Gmb Formed by the outermost nozzle Gmc Glass fiber formed by the outermost nozzle Gmd Glass fiber formed by the outermost nozzle Gs Strand HL Horizontal line LD Longitudinal direction of bushing SD Transverse direction of bushing θa Outermost nozzle θb The angle between the horizontal line and the glass fiber formed by the outermost nozzle θc The angle between the horizontal line and the glass fiber formed by the outermost nozzle θd The angle between the horizontal line and the glass fiber formed by the outermost nozzle The angle between the glass fiber and the horizontal line

Claims (5)

In a method for producing a strand by discharging molten glass from a plurality of nozzles provided in a rectangular bushing to form glass fibers with an irregular cross section and converging the glass fibers with a gathering shoe,
When viewed from the longitudinal direction and the lateral direction of the bushing, the angle formed by the horizontal line and the glass fibers formed by the outermost nozzle among the plurality of nozzles for discharging the molten glass is 70° or more. 89° or less ,
A step of cooling the molten glass discharged from the nozzle with a cooling unit,
A method of manufacturing a strand , wherein the cooling part includes a flow path for circulating a coolant along the longitudinal direction of the bushing . In a method for producing a strand by discharging molten glass from a plurality of nozzles provided in a rectangular bushing to form glass fibers with an irregular cross section and converging the glass fibers with a gathering shoe,
When viewed from the longitudinal direction and the lateral direction of the bushing, the angle formed by the horizontal line and the glass fibers formed by the outermost nozzle among the plurality of nozzles for discharging the molten glass is 70° or more. 89° or less,
A method of manufacturing a strand, wherein the nozzle has a nozzle hole elongated along the longitudinal direction of the bushing . 3. The method for manufacturing a strand according to claim 1 , wherein the number of said nozzles is 155 or more. 2. The method of manufacturing a strand according to claim 1 , wherein the cooling part is provided on the bushing and protrudes downward from the lower end of the nozzle. The method for manufacturing a strand according to claim 1 or 4, wherein the nozzle has a nozzle hole elongated along the longitudinal direction of the bushing.

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