JPS61219732A - Production of glass fiber - Google Patents

Abstract

PURPOSE:To produce glass fibers having a deformed cross-section by spinning molten glass into molten filaments through each pair of closely arranged nozzle holes and joining the filaments to each other. CONSTITUTION:Molten glass 17 is spun into molten filaments through each pair of closely arranged nozzle holes 18A, 18B in a nozzle plate 12, and the molten filaments are joined to each other and solidified by rapid cooling with cold air blown from a cold air blower 16 to form filaments 20 having a deformed cross-section. The nozzle plate 12 has many pairs of nozzle holes 18A, 18B and conical or spherical recesses 19 each including one pair of nozzle holes 18A, 18B. A bundling agent is applied to the filaments 20 with an applying roll 13, the filaments 20 are bundled with bundling rolls 14 to form a strand 21 and this strand 21 is coiled around a coiling pipe 22 of a coiler 15.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing glass fibers having irregular cross-sections such as oval, elliptical, cocoon-shaped, polygonal, etc.

Conventional technology Generally, glass fibers are manufactured by spinning molten glass through a punching machine with a large number of circular cross-section nozzle holes to form a large number of filaments, and then collecting and winding these filaments into a strand. .

Each filament of glass fiber produced has a circular cross-sectional shape. The main use of glass fiber is thermosetting resin.

It is a reinforcing material mixed into thermoplastic resins. A treatment agent is generally attached to the surface of the glass fiber to provide adhesive strength at the glass-resin interface.

Problems to be Solved by the Invention In recent years, it has been increasingly desired to improve the strength of composite materials containing resin and glass fiber. Additionally, thin strands are now required for long fiber applications such as filament winding, pultrusion, roving cloth, and electrical insulation cloth.

As a result of various studies in view of such requests, the present inventors have found that it is important to strengthen the adhesive force between glass fibers and resin in order to improve the strength of composite materials. It has been found that glass fibers having irregular cross-sections such as oval, elliptical, cocoon-shaped, polygonal, etc. can be used instead of the conventional circular cross-section. What is the cause of this?

Glass fibers with an irregular cross section have a larger specific surface area than those with a circular cross section, and therefore the total adhesive force between the glass fibers and the resin is considered to be greater, resulting in a greater reinforcing effect. Further, the cross-sectional shape is such that the outer periphery has a recess. In addition, since the adjacent fibers fit into the recess and it becomes difficult for the fibers to separate, the reinforcing effect becomes even greater.

It has also been found that when the cross section is flat, such as in a cocoon shape, the glass fibers overlap flatly and form thin strands. However, glass fibers with such irregular cross sections are extremely difficult to manufacture. That is, as mentioned above, in the production of glass fiber, molten glass is spun out from a nozzle hole and made into fibers, but at this time, the molten glass has a low viscosity and a high surface tension at high temperatures, so the cross section of the nozzle hole is Even if the fibers have an irregular cross section, the molten glass spun from the nozzle hole immediately becomes a circular cross section, making it impossible to obtain glass fibers with the desired irregular cross section.

The present invention aims to solve these problems, and aims to provide a method for manufacturing glass fibers having irregular cross-sections such as oval, elliptical, eyebrow-shaped, and polygonal shapes.

Means for Solving the Problems The present invention, which was made to achieve the above objects, spins molten glass from a plurality of nozzle holes arranged closely.

It is characterized by joining the spun molten glass together to form a single filament.

In this way, molten glass is spun out from multiple nozzle holes,
When the molten glass is then bonded to form a single filament, the temperature of the molten glass at the time of bonding has decreased to a certain extent and the viscosity has increased. Compared to spinning from

Eventually, the molten glass has a weak tendency to deform into a circular shape.

Glass fibers having irregular cross-sections such as oval, elliptical, cocoon-shaped, and polygonal shapes can be obtained.

Embodiment B The embodiments of the present invention shown in the following nine drawings will be described in further detail.

FIG. 1 shows an oval and elliptical cross section produced by the method of the present invention.

FIG. 2 is a schematic side view showing an example of an apparatus for manufacturing glass fibers having a flat irregular cross section such as an eyebrow shape, and FIG. 2 is a front view of the main parts thereof. Reference numeral 1) is a bushing having a nozzle plate 12 with a large number of nozzle holes at the bottom, 13 is a sizing agent application roller, 14 is a focusing roller, and 15 is a winding device.

16 is a cold air blowing device that blows out cooling gas (hereinafter referred to as cold air). As shown in FIG. 3, the nozzle plates 12 are arranged close to each other! A pair of nozzle holes 18A, 1
8B are formed in many pairs, and each pair of nozzle holes 18 is formed on the lower surface of the nozzle plate 12, as can be clearly seen from FIG.
A conical or spherical recess 19 is formed centered at the center of A and 18B.

1 and 2, the molten glass 17 supplied to the bushing 1) is inserted into each pair of nozzle holes 18A of the nozzle plate 12.
, 18B, 9 are then joined to each other, and are rapidly cooled and solidified by cold air blown from the cold air blowing device 16, resulting in a filament 20 having a relatively flat irregular cross section such as an oval, an ellipse, or a cocoon shape. . multiple filaments 20
is coated with a sizing agent by the sizing agent application roller 13, and then bundled into a strand 21 by the sizing roller 14, and! It is wound onto the winding tube 22 of the winding device 15.

During this process, when the strand 21 runs on the sizing agent application roller or guide, each filament falls flat and overlaps, resulting in a strand that is flatter than before (all filaments are aligned facing the same direction). By the method described above, a flat strand of glass fibers with irregular cross-sections such as oval, elliptical, and eyebrow shapes is produced. is necessary. Molten glass spun from a nozzle hole generally has a low viscosity and a high surface tension, so it has a strong tendency to immediately become circular in cross section. For this purpose, the molten glass spun from the pair of nozzle holes 18A and 18B is joined,
The cross section can also be shaped like a cocoon.

Before the molten glass solidifies, its cross section may be deformed into an oblong or elliptical shape due to surface tension, and finally become circular. This tendency is stronger as the distance between nozzle holes becomes shorter.

Therefore, if the nozzle holes are spaced too closely, the filament will have a circular cross-sectional shape. On the other hand, if they are too far apart, the molten glass from each nozzle hole will not join and will become two filaments with a circular cross section. Therefore, the distance between the nozzle holes in multiple pairs will not be one circular cross section based on the spinning conditions. Also, it is necessary to set the fiber so that it does not separate into two fibers. The lower surface of the nozzle plate 12 may be a flat surface, but if the recess 19 is formed as shown in FIG. cooling is weakened, and the molten glass from the two nozzle holes is more likely to join together. In other words, the recess 1
By providing 9, it becomes possible to widen the interval between the nozzle holes 18A and 18B, and it becomes possible to manufacture glass fiber with a more elongated cross section.

The shape of the recess 19 is not limited to the conical or spherical shape formed in each of the multiple pairs of nozzle holes, as shown in FIG. 5(A).

They may be formed into grooves as shown in (b) and (c), and instead of being formed by deforming the nozzle plate 12, these recesses 19 may be formed by cutting the bottom surface of the nozzle plate 12 as shown in FIG. The cross-sectional shape of the nozzle holes 18A and 18B may be any shape such as an ellipse, an oval or three circles instead of the rectangle shown in FIG. It is preferable to have an elliptical shape because it is possible to produce glass fibers with a long and narrow cross-sectional shape that has a large specific surface area.In the nozzle plate shown in FIGS. 4d) was preferably set between 0.1fi and lfi. When the gap d is smaller than 0.1, the cross section of the filament may become circular, and when it is larger than lin, the filament may split into two.

The cold air from the cold air blowing device 16 rapidly cools the filament spun from the nozzle plate and accelerates solidification. this is.

The molten glass spun from two nozzle holes and joined together to form a cocoon-shaped cross section with large irregularities is prevented from deforming into a circular cross section due to its own surface tension, so This is an effective means for producing glass fibers. Air or nitrogen is usually used as the gas for cooling, but other gases such as inert gas may be used depending on the cost. Although the cold air blowing device 16 is shown in one drawing as having a large number of cold air blowing pipes 25 provided corresponding to many pairs of nozzle holes, it is not limited to this example. The direction of the cold air blowing can range from parallel to perpendicular to the nozzle surface, but most preferably at an angle of 75 degrees to 85 degrees to the nozzle surface. It is best to spray toward the nozzle surface. When spraying at an angle smaller than this, it is preferable to spray from opposite directions while keeping a balance, as spraying only from the L direction may cause disturbances in the flow of the glass fibers. The amount of cold air is preferably selected from 10 d/msn pairs to 21)/lin pairs.

If the air flow is less than 101) 7/win pairs, there is not much cooling effect, while if it is more than 21/win pairs, the air flow will disrupt the flow of glass fibers, causing problems such as fibers getting tangled or separating into filaments with a circular cross section. Sometimes.

It goes without saying that the cold air blowing device 16 may be omitted if the cross-sectional shape of the filament is maintained even without blowing cold air.

It is also effective to lower the temperature and increase the viscosity of the molten glass extruded from the nozzle plate as a means of inhibiting the tendency of the molten glass spun from the nozzle plate to deform into a circular cross section. However, if the viscosity is simply increased, the amount of spinning decreases and the glass fibers produced become thinner. Therefore, it is preferable to pressurize the molten glass in the bushing by an appropriate method and extrude the molten glass under pressure. By extruding the molten glass under pressure in this way, it is possible to extrude the molten glass in a highly viscous state, which further limits the tendency of the spun molten glass to deform into a circular shape, creating a more uneven cocoon shape. of glass fiber is obtained. The higher the pressure applied to the molten glass, the more viscous the molten glass can be spun, and it is preferable from the point of view of maintaining the deformation. However, since there is a limit on the strength of the bushing, 1 usually the pressure is 8 kg/- or less. preferable.

In the above device, two nozzle holes are placed close to each other, and the molten glass spun from the two nozzle holes is bonded to form a single filament, but instead of this, three or more nozzle holes are placed close to each other. It is also possible to produce a glass fiber with an irregular cross section by arranging the nozzle holes and joining the molten glass spun out from these nozzle holes to form a single filament.

FIGS. 7 and 8 show three nozzle holes 18A with a circular cross section.

18B and 18C are arranged close to each other and at the apex positions of an equilateral triangle, and a nozzle plate 12 is shown in which a conical recess 19 is provided in a region including each nozzle hole on the lower surface.

By using this nozzle plate 12 and joining the molten glass spun from each nozzle hole into a single filament in the same manner as described above, it is possible to manufacture a glass fiber having a roughly triangular cross section. In this case, by appropriately adjusting the amount by which the molten glass spun and bonded from the three isle holes is deformed into a circular shape due to surface tension, a triangular shape with a depression on each side is formed as shown in Figure 10. Alternatively, each side may be substantially straight or bulged outward. By increasing the number of nozzle holes arranged close to each other to four or five, it is also possible to manufacture glass fibers with various irregular cross-sections, such as square or pentagonal. In any case, the cross-sectional shape of the nozzle hole used is not limited to circular, but may be rectangular, oval, or
It can be any shape such as an oval shape. Furthermore, the arrangement of the nozzle holes is not limited to the apex positions of regular polygons such as regular triangles and squares, but can be placed in nine different positions.

Thereby, glass fibers with various cross-sectional shapes can be obtained.

Example I Glass fiber was manufactured using a nozzle plate having nozzle holes 18A, 18B and a recess 19 having the shape and size shown in Table 1 and FIGS. 3 and 4. A glass fiber having a cocoon-shaped cross section as shown in FIG. 9 was obtained. When a rod is made from a strand of glass fiber as a pultrusion, the bending strength is improved by 10 to 15% compared to conventional glass fiber having a circular cross section.

Table 1 Nozzle hole shape Rectangular nozzle long side 2.5 Tsuru nozzle short side 1.1 Tsuru Molten glass temperature 1240℃ Spinning pressure Normal pressure (glass head pressure) Cold air volume 0.51 /win vs. blowing angle 75 degrees Cold air blowing pipe diameter 2fi Filament major axis (a > 30μ Filament minor diameter (b) 10μ Filament center diameter (C) 0.9~o, s x b Example ■ Shape shown in Table 2 and Figures 7 and 8 Glass fiber production was performed using a nozzle plate having one-dimensional nozzle holes 18A, 18B, and 18C and a recess 19.

A glass fiber having the dimensions shown in Table 2 and the approximately triangular cross section shown in FIG. 10 was obtained. When the bending strength was measured using FRTP using a strand made of this glass fiber, the bending strength was 1 compared to that of conventional glass fiber with a circular cross section.
It improved by 0-15%.

Table 2 Nozzle hole shape Circular nozzle position Equilateral triangle apex nozzle diameter
1.6 Tsuru molten glass temperature 1200℃ Spinning pressure Normal pressure (glass head pressure) Cold air volume 0.51 /win Concave blowing angle 75 degrees Cold air blowing pipe diameter 2 Tsuru concave 19 diameter 4 Centrifugal filament diameter (R) 10μ Effects of the Invention As explained above, according to the present invention, the molten glass spun from a plurality of nozzle holes is bonded to each other to form one filament, so that the surface of the molten glass after bonding is The amount of circular deformation due to tension is small, and as a result, glass fibers with irregular cross-sections such as oval, elliptical, cocoon-shaped, and polygonal shapes can be manufactured. The glass fiber thus produced has an increased specific surface area compared to conventional glass fibers with a circular cross section, and has a high adhesive strength to resin when used as a reinforcing material for 131 composite material.

The strength of composite materials can be improved. In particular, for glass fibers with a cocoon-shaped cross section, the adhesive force between filaments is large due to the interlocking effect of the filaments.
? J [It has the advantage that the reinforcing effect on the composite material is even higher, and a wide and thin strand can be obtained, and a thin woven fabric can be manufactured using this strand.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing one example of an apparatus used to carry out the method of the present invention, FIG. 2 is a front view of the main parts thereof, and FIG. 3 is a bottom view of the nozzle plate 12 used in the apparatus shown in FIG. 4 is a cross-sectional view taken along the line IV-mV in FIG. 3, FIG. 5 is a perspective view showing a modified example of the nozzle plate, and FIG. 6 is a sectional view showing still another modified example of the nozzle plate. Figure 7 is a cross-sectional view of a part of a nozzle plate used for manufacturing glass fibers with an approximately triangular cross section, Figure 8 is a bottom view thereof, and Figure 9 was created based on a cross-sectional micrograph of the glass fiber made in Example ①. Cross-sectional view. FIG. 10 is a cross-sectional view created based on a cross-sectional micrograph of the glass fiber produced in Example (2). 12-nozzle plate 13-sizing agent application roller 14...
- Focusing roller 15 - Winding device 18A, 18B, 18
C.-Nozzle hole 19-recess 20...filament
21・-Strand 25...Cold air blowing vibe

Claims (7)

[Claims] (1) A method for producing glass fibers, which comprises spinning molten glass from a plurality of closely spaced nozzle holes, and bonding the spun molten glass to each other to form a single filament. (2) The nozzle plate in which the nozzle holes are formed has a concave portion formed on its lower surface, centered at the center of the plurality of nozzle holes, and spanning each nozzle hole. method for manufacturing glass fiber. (3) The method for manufacturing glass fiber according to claim 1 or 2, wherein the plurality of nozzle holes are two nozzle holes with a rectangular cross section arranged in a longitudinal direction. (4) The method for manufacturing glass fiber according to claim 1 or 2, wherein the plurality of nozzle holes are two nozzle holes having an oval cross section arranged in a longitudinal direction. (5) The method for manufacturing glass fiber according to claim 1 or 2, wherein the plurality of nozzle holes are three nozzle holes arranged on the vertices of a triangle. (6) The method for manufacturing glass fiber according to any one of claims 1 to 5, wherein the recessed portion is conical or spherical. (7) The method for manufacturing glass fiber according to any one of claims 1 to 5, wherein the recess is groove-shaped.