JPS6126534A - Production of hollow glass fiber - Google Patents

Abstract

PURPOSE:To produce continuously homogeneous hollow glass fibers stably in a simple apparatus, by spinning a molten glass placed between both of a specific double crucible through the tip of a nozzle. CONSTITUTION:A double crucible is constructed from a platinum alloy or ceramic to give a relation theta1>=theta2 (theta1 is the angular aperture of a conical nozzle 3 at the bottom of an outer crucible 1; theta2 is the angular aperture of a conical nozzle 4 at the bottom of an inner crucible 2) and the relation phi1<=phi2 (phi1 is the caliber of the nozzle 3; phi2 is the caliber of the nozzle 4, and both are within 4-10mm. range) and 1-3mm.(l) interval between the bottoms of the crucible 1 and the crucible 2. The resultant double crucible is then placed in a heating furnace kept at 1,000-1,250 deg.C, and glass cullets are charged from a glass cullet inlet into the space between both crucibles 1 and 2 and melted to give a molten glass 5, which is then made to flow from the nozzles 3 and 4 and wound by a drum at 70- 1,400m/ min speed. Air is introduced from the inner crucible 2 to give continuously the aimed hollow glass fibers.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing hollow glass HA11I.

Glass AM is useful because it has high strength and is inexpensive, but it has a high specific gravity, so there is a demand for its weight reduction.

Hollow glass fiber has attracted attention due to its properties, and is used as a raw material for composite materials.
It is expected to be put to practical use as a heat insulating material, a functional material, etc.

As a method for manufacturing hollow glass fibers, the current method is known.

l) A method in which two types of crucibles, large and small, each having a hole in the bottom are stacked one on top of the other with an interval between them, and the molten glass placed between them is spun from the hole in the bottom (Japanese Patent Laid-Open No. 134532/1983).

2) Place 3 to 5 mm of molten glass in a crucible with a hole at the bottom.
A method of spinning yarn from the hole at the bottom while putting it in a thick layer and allowing air to get involved.

3) A method in which molten glass is placed in a crucible having a spinning nozzle at the bottom, air is blown from above the spinning nozzle, and spinning is performed while removing the molten glass in the center of the nozzle (US Pat. No. 3,510,393).

However, method 1) above uses a crucible.

The manufacturing conditions of the hollow fibers change slightly depending on the so-called wetting condition with the glass, and it is not suitable for stable production. Method 2) is not suitable for stable production. Method 3), which is greatly affected, has the disadvantage that the structure of the mounting is extremely complicated.

Means for Solving the Problems In view of the above-mentioned points, the present inventor has conducted various studies and has discovered a method for stably and continuously producing homogeneous hollow glass fibers using a simple device. completed the invention.

That is, the present invention provides an opening angle of 70 to 120 at the bottom of the crucible.
Two types of crucibles, large and small, each equipped with a conical nozzle with a diameter of 4 to 10 mm are placed one on top of the other so that the interval 4 between the bottoms is 1 to 3 rrrlrrI, and the angle between the nozzles of the outer crucible is 01.
and the opening angle θ2 of the nozzle of the inner crucible are θ1≧θ
A double crucible is used in which the nozzle diameter φ1 of the outer crucible and the nozzle diameter φ2 of the inner crucible are in the relationship φ1≦φ2, and the molten glass placed between both crucibles is passed through the nozzle. The present invention relates to a method for producing hollow glass fibers characterized by spinning from the tip.

The present invention enables stable continuous production of hollow glass fibers by improving the shape of the nozzle, which had many problems in the past. A vertical cross-sectional view of an example of the double crucible used in the present invention is shown in Fig. Fig. 1 shows an enlarged view of the nozzle portion, and Fig. 2 shows an enlarged view of the nozzle portion.

Here, the opening angle θ1 of the conical nozzle (3) on the bottom of the outer crucible (1) and the opening angle θ1 of the conical nozzle (3) on the bottom of the inner crucible (2) are
The opening angle θ2 of 4) is within the range of 70 to 120° and satisfies the relationship θl≧02. Also, the diameter of the nozzle (3) of the outer crucible (1) is φ1, and the nozzle of the inner crucible (2) (
4) The diameter φ2 is within the range of 4 to 10 mm, and φ1≦
The relationship is φ2. Inner crucible (2) and outer crucible (1)
The distance l between the bottom surface and the bottom surface is 1 to 3 mm. The distance is l m
If it is narrower than m, the supply of molten glass (5) will be insufficient and the thread will break easily, and if it is wider than 3 mm, the supply of molten glass (5) will be too large and the glass will accumulate in the nozzle part, making it difficult for the thread to become hollow.

In the present invention, by using a double crucible having a nozzle having the above-described shape, problems caused by the wetness of the nozzle can be solved and stable continuous production of hollow glass fibers can be made possible.

Furthermore, in the double crucible used in the present invention, glass cullet to be used as a raw material can be introduced into the gap between both crucibles by appropriately opening a glass cullet inlet (not shown) in the upper flat part, etc. .

As the material of the crucible, platinum alloy, ceramics, etc. can be used. Platinum alloys are desirable because of their excellent heat resistance and corrosion resistance, but are expensive. Ceramics have the disadvantage of being easily broken, but they are inexpensive and have high heat resistance, so there is no problem in practical use.

In the present invention, first, the above-mentioned double crucible is
The crucible is placed in a heating furnace maintained at 50°C, and glass cullet is introduced between both crucibles through the glass cullet inlet. Next, once the glass cullet has melted and flowed out from the tip of the nozzle, it is wound up on a drum, etc. at a speed of about 70 to 1400% in, to continuously obtain hollow glass fibers while guiding air through the inner crucible. be able to.

In the present invention, as a raw material for the molten glass, glass cullet or marble, which has been prepared in advance so as not to contain bubbles, can be used.

The hollow glass fiber obtained by the present invention usually has an outer diameter of 1
It is a long fiber with an inner diameter of about 0 to 100 μm and an inner diameter of about 3 to 30 μm. The thickness of the fiber can be adjusted by various factors such as the shape of the nozzle, the diameter of the nozzle, the temperature of the crucible, and the winding speed of the glass fiber.

Effects of the Invention According to the method of the present invention, the outer diameter is 10 to 100 μm, the inner diameter is 3 to
It becomes possible to stably and continuously manufacture hollow glass fibers with a constant quality of about 3 Qltm.

Example Next, the present invention will be explained in more detail by showing examples.

Example 1 A slurry made of clay, waxite, and chamotte was cast into a plaster mold to obtain a double crucible with a wall thickness of about 3 plates. The opening angle of the conical nozzle of the inner crucible and the opening angle of the conical nozzle of the outer crucible are both 120°, the diameter of the nozzle of the outer crucible is 7 mm, and the diameter of the nozzle of the inner crucible is 81T11T.
1. The space between the bottoms of the inner crucible and the outer crucible was one plate.

This double crucible was placed in a silicon carbide heating element electric furnace, and
After heating to 00'C and holding for several hours, lower the temperature to 120
It was kept at 0°C.

Next, 5i0250%, 0a018%, B20g 1
7%, Al2089.41% and Nano 5.57%
A glass cullet consisting of a glass cullet was placed between the double crucible through the glass cullet inlet. Once the cullet has melted and the glass has flowed out of the nozzle of the outer crucible, increase the temperature of the electric furnace to 115
The temperature was brought to 0° C. and the glass was wound onto a 45 Q mm diameter AI drum rotating at 40 Or pm.

An electron microscope photograph (215x magnification) of the hollow glass fiber thus obtained is shown in FIG. The glass fiber thus obtained had an outer diameter of about 29 μm and an inner diameter of about 13 μm, and clearly had a macaroni-like structure. This glass fiber had a tensile strength of 56.8 kg/mm2 and an apparent specific gravity of 1.98 (true specific gravity of 2.48).

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a double crucible used in the present invention. FIG. 2 is an enlarged view of the nozzle portion of the double crucible shown in FIG. 1. FIG. 3 is an electron micrograph (215x magnification) of the hollow glass fiber obtained in Example 1. In the plan view, (1) is the outer crucible, (2) is the inner crucible,
(3) is the nozzle of the outer crucible, (4) is the nozzle of the inner crucible, and (5) is the molten glass. (That's all) Figure 1? Figure 1-2

Claims (1)

[Claims] (1) Two types of crucibles, large and small, each equipped with a conical nozzle with an opening angle of 70 to 120 degrees and a diameter of 4 to 10 mm are placed on top of each other so that the interval l between the bottoms is 1 to 3 mm, and the outer crucible is The opening angle θ_1 of the nozzle of the inner crucible and the opening angle θ_2 of the nozzle of the inner crucible have a relationship of θ_1≧θ_2, and the aperture diameter φ_1 of the nozzle of the outer crucible and the aperture diameter φ_2 of the nozzle of the inner crucible have a relationship of φ_1≦φ_2. A method for producing hollow glass fibers, which uses a heavy crucible and spins molten glass placed between both crucibles from the tip of a nozzle.