JPS62187136A - Production of glass fiber - Google Patents

Abstract

PURPOSE:To produce the titled modified cross-section glass fibers by providing plural nozzle holes respectively to plural chips protruded from a nozzle plate, and binding molten glasses spinned out from the nozzle holes to each other to obtain a single monofilament. CONSTITUTION:Plural chips 17 are protruded from the lower surface of the nozzle plate 12, and plural nozzle holes 18A and 18B are provided to each chip 17. Molten glass is spinned out from the nozzle holes 18A and 18B. The spinned molten glasses spinned out from the nozzle holes are bound at each chip 17 to obtain a single monofilament 20. Consequently, the paralleling action is facilitated at the start of spinning or in cutting, the glass in the furnace is never devitrified, and the modified cross-section glass fibers can be stably obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing glass fibers having irregular cross-sections such as oval, elliptical, cocoon-shaped, and polygonal shapes.

[Conventional technology]

Generally, glass fiber is manufactured by spinning molten glass from a bushing having a large number of nozzle holes with a circular cross section 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.

[Problem that the invention seeks to solve]

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 one means of meeting these demands,
Instead of the conventional circular cross-section, the cross-section of the glass fiber may be an oval, elliptical, cocoon-shaped, polygonal or other irregularly shaped cross-section. In other words, glass fibers with irregular cross sections have a larger specific surface area than those with circular cross sections, and therefore the total adhesive force between the glass fibers and the resin is large, resulting in a greater reinforcing effect. Assuming a flat cross section of
The glass fibers can overlap flatly to form thin strands. However, it is difficult to manufacture glass fibers with such irregular cross sections. 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 even if 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.

As a result of intensive research into a method for producing glass fibers with such irregular cross-sections, the present applicant has developed a method in which molten glass is spun from a plurality of closely spaced nozzle holes, and the spun molten glass is joined together. We have developed a method for manufacturing glass fiber with an irregular cross section into a single filament, and have previously applied for a patent (
(Japanese Patent Application No. 60-57536).

By the way, in the above patent application, a spinning device equipped with a nozzle plate formed by punching a large number of nozzle holes in a flat plate was used as a device for implementing the manufacturing method, but this device has problems that need to be improved. It turned out that there was a point.

That is, in this device, when the glass filament is cut by a foreign object, molten glass is discharged from the nozzle hole.

Due to the interfacial tension between the glass and the nozzle plate, it flows sideways along the outer surface of the nozzle plate, cutting other filaments.
Also, in order to align the cut filaments, I used something like a pins to pull each filament together.

They have to be picked out, and it takes a lot of time and effort to pull them all together. Also, how to make irregular cross-section threads.

It is desirable to flow the molten glass from the nozzle hole in a fairly high viscosity state, that is, at a low temperature, but to do so, the temperature of the spinning furnace must be relatively low, and the liquidus temperature of the glass in the furnace must be kept low. When the temperature is close to the spinning temperature, there is a risk of devitrification in the corners of the furnace.

The present invention has been made in view of these problems, and provides a method for producing glass fibers with irregular cross sections that facilitates the alignment operation at the start of spinning or cutting, and that is less likely to cause devitrification in the furnace glass. The purpose is to

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention uses a nozzle plate for spinning molten glass that has a plurality of chips on its lower surface and each chip has a plurality of nozzle holes, and each chip has a plurality of nozzle holes. It is characterized in that the molten glass spun from the nozzle hole is joined together to form a single filament.

[Effect]

As mentioned above, in the present invention, molten glass is spun from multiple nozzle holes of each chip and then joined to form a single filament, so that the temperature of the molten glass at the time of joining is lowered to a certain degree and the viscosity is reduced. It's getting expensive.

For this reason, compared to the case where the molten glass is simply spun from a single nozzle hole with an irregular cross section such as an oval or an ellipse, the tendency of the molten glass to deform into a circle is weaker, and the final shape is an oval or an ellipse.

It is possible to obtain glass fibers having irregularly shaped cross sections such as eyebrow shapes and polygons. Furthermore, the multiple nozzle holes that form one filament with an irregular cross section are formed in a single chip that protrudes from the bottom surface of the nozzle plate, so when the filament is cut, the glass itself does not flow sideways and falls under its own weight. However, there is no need to cut other filaments, and the time and effort for aligning can be shortened. Furthermore.

By providing a tip, if the spinning temperature at the tip of the tip is selected to give the desired viscosity, the glass temperature in the furnace will be much higher than this spinning temperature (for example, 5
0 to 60°C), which makes it safer against devitrification in the furnace.

〔Example〕

The present invention will be described in more detail below with reference to embodiments of the present invention shown in two drawings.

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 FIGS. 3 and 4, the nozzle plate 12 is provided with a large number of chips 17 protruding from the bottom surface, and each chip 17 has a pair of nozzle holes 18 adjacent to each other.
A, 18B are formed, and at the lower end thereof.

A conical or spherical recess 1g is formed around the center of the pair of nozzle holes 18A, 18B.

Next, a method for manufacturing glass fibers with irregular cross sections using the above-mentioned apparatus will be explained. In FIGS. 1 and 2, the molten glass 23 supplied to the bushing 1) is spun out from a pair of nozzle holes 18A and 18B of each tip 17 of the nozzle Fi12, and then joined together and blown from the cold air blowing device 16. It is rapidly cooled and solidified by the applied cold air, and has an oval cross section.

The filament 20 has a relatively flat irregular cross section, such as an ellipse (see FIG. 8) or an eyebrow shape (see FIG. 9). A large number of filaments 20 are coated with a sizing agent by a sizing material application roller 13, then bundled into a strand 21 by five sizing rollers 14, and wound onto a winding tube 22 of a first 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 this method, a flat strand is produced, which is a collection of glass fibers with irregular cross-sections such as oval, elliptical, and eyebrow shapes.

In the above apparatus, at the start of spinning, molten glass begins to flow out from the bushing 1) through the nozzle hole.

After this glass accumulates at the bottom end of each chip, it falls under its own weight without flowing laterally, forming a filament.

In this way, alignment at the start of spinning becomes extremely easy. Also, even if the filament breaks during spinning,
The molten glass discharged from the chip does not flow laterally to the lower end of the adjacent chip, thereby preventing cutting of the adjacent filament.

In order to obtain glass fibers with a flat and irregular cross section by the method of the present invention, the following precautions must be taken. The molten glass spun from the nozzle holes generally has a low viscosity9 and a high surface tension, so there is a strong tendency for the cross section to immediately become circular.For this reason, the molten glass spun from the pair of nozzle holes 18A and 18B is joined, Even if the cross section is cocoon-shaped, the cross section may deform into an oval or an ellipse due to surface tension until the molten glass solidifies, and finally become circular. This tendency is stronger as the distance between the nozzle holes becomes shorter, and therefore, if the distance between the nozzle holes becomes too close, the cross-sectional shape of the filament becomes circular. On the other hand, if they are too far apart, the molten glass from each nozzle hole will not be joined and will become two filaments with a circular cross section.Therefore, the distance between the nozzle holes in 6 pairs should be adjusted so that the nozzle hole does not have a circular cross section of 9 based on the spinning conditions. Furthermore, it is necessary to set the fiber so that it does not separate into two fibers. The lower end of the chip 17 on the lower surface of the nozzle plate 12 may be a flat surface, but if the recess 19 is formed as shown in FIGS. When the concave portion 19 is formed, the cooling by the outside air is weakened, and the molten glass from the two nozzle holes is easily bonded together. This makes it possible to manufacture glass fibers with a more elongated cross section. In the temporary nozzles shown in FIGS. 3 and 4, it was preferable that the gap between the pair of nozzle holes 18A and 18B (FIG. 3d) be set between 0.1 n and 1 fi. When this gap d is smaller than 0.1fi, the cross section of the filament may become circular, and 1■
When it is larger than 1, the filament may split into two.

The temperature of the molten glass spun from the nozzle hole is preferably low as long as it does not interfere with spinning. If the spun glass temperature is low, the glass viscosity will be high, and the glass fibers that have been joined to have an irregular cross section will become circular in cross section. Since the tendency to deform is inhibited, fibers with a high degree of deformation are formed. Note that the tip 17 provided on the bottom surface of the nozzle plate 12 has the effect of cooling the molten glass that passes through it, so the temperature of the molten glass in the furnace is adjusted to the desired glass temperature at the tip of the tip, taking into account the cooling effect of this tip. (compared to spinning temperature).

set high. Therefore, even if the temperature of the liquid glass in the furnace is slightly uneven, it is unlikely that the temperature will drop to the point where devitrification occurs (and stable operation is possible. However, if it is too long, there will be problems such as increased passing resistance and a complicated structure.Also, as mentioned above, this chip 17
The length also serves to prevent the flowing molten glass from flowing laterally, and from this point of view, the longer the length, the better.

Taking these into consideration, the length of the chip 17 should be 1~
Approximately 5 fins are preferred, and more preferably around 3 fi.

Molten glass may be spun using only the molten glass head inside the bushing as in the past, but if you try to spin it at a low temperature as mentioned above, the viscosity is high, so the amount of discharge will decrease and the production will be delayed. The glass fibers may become thinner. Therefore, the molten glass in the bushing may be pressurized by an appropriate method to extrude the molten glass under pressure.By extruding the molten glass under pressure in this way, the molten glass can be extruded in a highly viscous state. This makes it possible to further limit the tendency of the spun molten glass to deform into a circular shape, and to obtain cocoon-shaped glass fibers with larger irregularities. The higher the pressure applied to the molten glass, the more viscous the molten glass can be spun, which is preferable from the point of view of maintaining the deformation. However, since there is a limit on the strength of the bushing, the pressure is usually 8 kIr/cd or less. preferable.

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. In one drawing, the cold air blowing device 16 is shown as having a large number of cold air blowing vibes 25 provided corresponding to each chip.

The direction of the cold air blowing is not limited to this example.
It is possible to do it from parallel to perpendicular to the nozzle surface.

The most desirable method is to spray toward the nozzle surface at an angle of 75 to 85 degrees.If you spray at an angle less than this, the flow of glass fibers will be disturbed if you spray from only one direction. To avoid this, it is preferable to blow the cool air in a balanced manner from opposing directions.The volume of cold air should be 10 d/s for each chip.
It is preferable to select from in to 21/mln.

If the air flow is less than 10 m1/sin, there is not much cooling effect, while if it is more than 21 m1/sin, the air flow may disrupt the flow of glass fibers, causing problems such as fibers getting tangled or separating into filaments with circular cross sections. .

In addition.

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

Although FIGS. 3 and 4 show an example of a nozzle plate that can be used in carrying out the present invention, this nozzle plate can be modified in various ways.
For example, the arrangement of the chips 17 is not limited to the staggered arrangement shown in FIG. 3, but may be arranged vertically and horizontally, and the chip shape is such that the chip 17A has a large guide hole 26 as shown in FIG. 18b.

As shown in FIG. 5B, an introduction recess 27 is provided at the upper end of the chip 17B, and a recess 19a consisting of a cylindrical part and a conical part is provided at the lower end, and a large guide hole 28 is provided in the chip 17C as shown in FIG. 5C.
In addition, the nozzle holes 18c and 18d may be inclined so as to approach each other, and the lower end portion may be flat. Furthermore, the cross section of the nozzle hole is not limited to circular, but may also be rectangular,
It can be any shape such as oval or oval. FIG. 6 shows a chip 17D in which rectangular nozzle holes 18e and 18f arranged in the longitudinal direction and a recess 19b at the lower end are formed. With this structure, it is possible to create a glass fiber having a long and narrow cross-sectional shape with a large specific surface area. I can do it.

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.

Figure 7 shows three nozzle holes 1 with a circular cross section in the chip 17H.
8g is placed at the apex position of an equilateral triangle, and furthermore, a conical recess 19c is provided in the area including each nozzle hole.

Using the nozzle plate equipped with this tip 17E, 1. In the same manner as above, the molten glass spun from each nozzle hole is joined to form a single filament, thereby producing glass fiber with a roughly triangular cross section. be able to. In this case, 3
By appropriately adjusting the amount by which the molten glass spun and bonded from the individual nozzle holes deforms into a circular shape due to surface tension,
As shown in FIG. 10, the shape may be a triangle with a depression on each side, or each side may be substantially straight or bulged outward. The number of nozzle holes formed on one chip is 4.

By increasing the number to 5, it is also possible to manufacture glass fibers with various irregular cross-sections such as square and pentagonal shapes. In addition.

In either case, the cross-sectional shape of the nozzle hole used is not limited to circular, but may be arbitrary such as rectangular, elliptical, oval, etc. Further, 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 at two various positions, thereby making it possible to obtain glass fibers with various cross-sectional shapes.

Examples Nozzle plate with tips shown in FIGS. 3 and 4 (Example 1.n), nozzle plate with tips shown in FIG. 5A (Example III), and a flat nozzle without tips Board (
Comparative Example) was used to produce glass fiber. Table 1 shows data such as the manufacturing conditions and the shape and dimensions of the filament obtained. Note that cold air was not blown. As is clear from this table, in the example of the present invention, it was possible to set the glass temperature in the furnace higher than when using a flat nozzle plate, and to significantly shorten the alignment time. .

Table 1 [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 a single filament. The amount by which the molten glass deforms into a circular shape due to surface 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. Furthermore, since multiple nozzle holes are formed on the tip that protrudes from the bottom surface of the nozzle plate, the molten glass discharged from the bottom end of the tip does not flow to the side tip, making alignment operations easy and quick when starting spinning or cutting. Moreover, the glass temperature inside the furnace can be made higher than the spinning temperature due to the cooling effect of the chips, so even if the spinning temperature is lowered, there is almost no devitrification inside the furnace and the raking operation is stable. is obtained.

[Brief explanation of drawings]

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. FIG. 4 is a sectional view taken along the line IV-IV in FIG. The figures are bottom views showing modified examples of the tips of the nozzle plate, and FIGS. 8, 9, and 10 are cross-sectional views of glass fibers that can be manufactured by the method of the present invention.

Claims (5)

[Claims] (1) A nozzle plate having a plurality of tips protruding from the bottom surface and each tip having a plurality of nozzle holes is used, molten glass is spun from the plurality of nozzle holes, and the molten glass is spun from the nozzle hole of each chip. A method for producing glass fiber, characterized by bonding glasses together to form a single filament. (2) The glass fiber according to claim 1, wherein each of the chips has a concave portion formed at a lower end portion thereof, centered at the center of the plurality of nozzle holes, and spanning each nozzle hole. Production method. (3) The method for producing glass fiber according to claim 1, wherein the nozzle holes formed in each of the chips are inclined at least in a lower end portion in a direction toward each other. (4) The method for manufacturing glass fiber according to any one of claims 1 to 3, wherein each chip has two nozzle holes. (5) Each chip is placed on the vertex of a triangle.
The method for producing glass fiber according to any one of claims 1 to 3, characterized in that the method has a number of nozzle holes. (6) The method for producing glass fiber according to claim 2, wherein the recessed portion has a conical or spherical shape.