JPH0637312B2 - Gel fiber cake in silica fiber manufacturing process - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gel fiber cake in a silica fiber manufacturing process.

[Prior Art] In the technology for producing silica fiber by the sol-gel method according to the present invention, a fiber in a gel state which is a precursor of silica fiber by extrusion from a spinning solution containing an organosilicon compound (hereinafter referred to as gel fiber) Say) to form.

In general, various forms of receiving fibers formed by continuous spinning or drawing are known in consideration of physical properties of fibers, means for transferring to the next step, and the like.

In the conventional glass fiber threading process by the melting method,
After the sizing agent is applied to the filaments coming out of the bushing, they are collectively formed into strands, and the tubes made of paper or plastic are wrapped with a tying member. The wound product of the strand just after the yarn is taken or spun is called a forming package or cake, not limited to the yarn taking step by the melting method.

When winding a strand composed of a plurality of fibers into a tube, there is a method of winding while twisting with a traverse guide. At this time, in the vicinity of the turning point of the strand, the relative movement of the traverse guide with respect to the fiber cake is as shown by the dotted line in FIG. However, since there is a gap between the traverse guide and the fiber cake, due to the inertia of the strand, the strand cannot follow the traverse guide, and more strands are actually fed out, and the solid line in FIG. Is wound up. For this reason, the winding density of the strands is higher at both ends of the fiber cake than in the central part, and it is easy to form a fiber cake in which both ends are swollen as shown in FIG.

In this way, the gel fiber cake wound in a state in which both ends are swollen, when unwinding the gel fiber from the outer peripheral portion in the next step, in the case of trying to derive the gel fiber parallel to the winding axis, , At least both ends rub each other, making it difficult to unwind at high speed. Further, in order to guide the gel fiber in the direction perpendicular to the winding shaft, a rotating shaft or a rotating device for the fiber cake is required.

In order to suppress the occurrence of the bulge at both ends of the gel fiber cake, there is a method in which the traverse guide and the tube are made extremely close to each other and the strand wound by the touch roll is pressed while being wound. However, this method is not suitable as a method of winding a fiber weak in friction or a fiber weak in bending at a high speed, such as a silica gel fiber, because the strand is always pressed by a touch roll.

On the other hand, in Japanese Patent Publication No. 57-20409, a strand composed of raw continuous fibers formed by extruding a viscous solution or dispersion of a metal compound, which is a precursor of a refractory metallized fiber, from a spinneret is moved. A method is disclosed in which the particles are deposited on a mesh belt and continuously fed to the subsequent firing step.

In addition to this method, as a means for continuously feeding fibers having relatively low strength before firing to the firing process, while drawing a regular eight-character shape on the coiler can as in the case of pitch-based carbon fibers. Methods for depositing precursor fibers are also known.

However, it is unsuitable for silica gel fibers to be left in such a free state that tension is not applied for the following reasons.

The silica gel fiber reacts with moisture in the air to further advance the polycondensation reaction, and the shrinkage amount increases with the passage of time. When strands consisting of fibers that shrink in this way are deposited in a free state, due to the difference in the amount of shrinkage of each fiber, each fiber does not become a neat and parallel strand during deposition. , Part of the fiber protrudes from the strand in a loop,
Strands with poor yarn alignment during firing and of course after firing.

In the silica fiber manufacturing technology, the spun gel fiber needs to be fired. In order to remove the organic components contained in the gel fiber in this firing step to efficiently perform the sintering and to obtain high-strength silica fiber, it is essential to apply a constant tension to the fiber during the firing step. is there. At this time, it is desirable that the tension applied to the strand is large within a range in which the strand does not break. Examples of the application method include a dancer roll method and a friction method. For this purpose, it is necessary to wind the gel fiber in a cake shape.

[Problems to be Solved by the Invention] In the present invention, a gel fiber cake is prepared by winding a strand composed of the above-mentioned gel fiber or a plurality of gel fibers on a tube using a traverse guide and keeping a distance from the traverse guide. It is intended to solve the above-mentioned problems caused by the forming method.

[Means for Solving Problems] The present invention has been made to solve the above-mentioned problems, and is made of gel fiber which is a precursor of silica fiber in the extrusion dry yarn method, The inclination angle is in the range of 60 ° to 85 °, and the winding angle is 60.
The present invention provides a gel fiber cake characterized by being in the range of not less than 90 ° and less than 90 °.

In the present invention, the gel fiber cake refers to a gel fiber (including a strand formed by bundling a plurality of gel fibers, the same in the following description) obtained by winding the gel fiber around a core material such as a tube. A roll.

FIG. 1 is an external view of the gel fiber cake of the present invention as seen from a direction perpendicular to a winding rotation axis (equivalent to the central axis of a tube), and FIG. 2 is an outer peripheral portion of the gel fiber cake of the present invention. FIG.

In FIG. 1, α is the inclination angle of the winding both ends,
In the figure, the angle β formed between the gel fiber and the central axis of the tube is the winding angle.

In the gel fiber cake of the present invention, the inclination angle (α) needs to be in the range of 60 ° to 85 °.
Such a shape is obtained by adjusting the traverse width so as to decrease with the passage of time from the start of winding.

When the inclination angle exceeds 85 °, the gel fibers are largely overlapped at both ends of the gel fiber cake, and the swelling at both ends is not sufficiently reduced. For this reason, when unwinding the gel fiber cake, there are many opportunities for the fibers to rub against each other and damage is likely to occur, which is unsuitable.

If the inclination angle is less than 60 °, the weight of the gel fiber that can be wound in one tube becomes too small, which is not suitable because it causes a problem in production efficiency.

Further, the gel fiber contracts by reacting with moisture in the atmosphere to cause a polycondensation reaction. Therefore, the overlapping density of gel fibers is one factor that determines the reaction between gel and water. Inclination angle (α) in gel fiber cake
Affects the overlapping density of the gel fiber,
From this point as well, the inclination angle of the fiber cake of the present invention is determined.

If the inclination angle exceeds 85 °, the gel fiber density at both ends of the fiber cake will be higher than that at the center, so the reaction between gel fiber and atmospheric moisture is a fiber with a low gel fiber density. It is smaller than the center of the cake. Therefore, the shrinkage of the fiber is larger in the central part than at both ends, and non-uniformity occurs, and the fiber cake is deformed. For this reason, the gel fibers on the outside and the gel fibers on the inside intersect with each other, and the friction between the gel fibers during unwinding increases. Alternatively, the fibers forming the strands have a non-uniform shrinkage amount, so that the fibers are not neatly aligned in parallel, and a part of the fibers protrudes from the strand in a loop shape. For this reason, a part of the fiber is cut and becomes fluff, which deteriorates the quality of the silica fiber, which is not suitable.

On the other hand, if the inclination angle is less than 60 °, the overlapping density of the gel fires at both ends will decrease, and due to the influence of the end faces of the fiber cake, it will be more likely to react with moisture in the atmosphere, and Shrinks more in comparison. In this case, the unwinding property is relatively good, but it is not suitable because it is difficult to remove the organic substances contained in the gel fiber in the firing step and the silica fiber is colored black.

Here, the following can be considered as the cause of the black coloring of the silica fiber. Gel fiber
By firing, residual water or organic matter scatters and finally becomes silica fibers. When the polycondensation reaction of the gel fiber proceeds excessively before firing, it is considered that the organic matter is prevented from being diffused during firing. That is, when the tilt angle is less than 60 °, it is considered that the gel fiber reacts too much with the atmosphere.

In the gel fiber cake of the present invention, the winding twist angle (β) must be 60 ° or more and less than 90 °. A more preferable range of the aya angle is 70 to 80 °.

When the twist angle is 90 °, the gel fibers are wound in parallel with each other, and due to the large shrinkage after winding, which is peculiar to the gel fibers, the inner gel fiber and the outer gel fiber are in close contact with each other. overlap. For this reason, unwinding of the gel fiber smoothly and without damage is impossible, which is unsuitable.

When the twist angle is less than 60 °, a large force is applied to the gel fiber by the traverse guide. For this reason, the gel fiber suffers a great deal of damage and causes cutting and fluff, which is not suitable.

As the method for unwinding the gel fiber from the fiber cake, the external removal method is preferable. This is because the gel fiber shrinks about 2% after winding, so the external removal method that does not involve tube removal is less problematic than the internal removal method.
It is not limited to the external pick-up method.

The fiber cake of the present invention is unwound and fired to obtain silica fibers. It is preferable to apply a tension to the gel fiber during firing. The tension is applied by a dancer roller or friction. The applied tension is preferably about 50 to 80% of the tensile strength of the gel fiber.

[Examples] Tables 1 and 2 show the evaluation results of gel fiber cakes wound under the following conditions.

Number of fibers that make up the strand: 120 Fiber diameter (oval or elliptical long diameter): Average 13
μm Winding speed: 150m / min Winding tube diameter: 300mm Traverse width: Max 254mm [Effect of the Invention] The present invention has the effect of significantly improving the unwinding property of the strand. In particular, since it is possible to reduce the frictional damage between the gel fibers or the strands upon unwinding, there is an effect that silica fibers with few fluff and high strength can be obtained. Also, the small number of fluffs and the high strength are effective in improving the yield through the manufacturing process of silica fibers by the sol-gel method.

Further, the present invention has an excellent effect in reducing monofilament breakage during winding.

Further, in the gel fiber cake of the present invention, the unavoidable shrinkage peculiar to the gel fiber is uniformly realized in the entire gel fiber forming the strand, and as a result, the generation of loops is substantially eliminated. It is also recognized that this makes it extremely easy to control the tension applied to the strand during firing by the dancer roll.

Further, according to the present invention, the effect of obtaining a silica fiber having an excellent quality which is not colored black by the firing step is recognized.

[Brief description of drawings]

FIG. 1: External view of the gel fiber cake of the present invention as seen from a direction perpendicular to the winding axis. FIG. 2: Partially enlarged view of the outer periphery of the gel fiber cake of the present invention FIG. 3: Traverse guide and strand Explanatory diagram showing movement Fig. 4: Appearance of fiber cake wound in a state in which both ends are swollen 1 ... Strand, 2 ... Tube, 3 ... Gel fiber cake, α ... Inclination angle, β ... ... Aya angle, A ... maximum value of traverse width, B ... minimum value of traverse width, 31 ... take-up rotary shaft, 32 ... take-up tube, 41 ... fiber cake, 42 ... take-up tube.

Claims (1)

[Claims] 1. A gel fiber which is a precursor of silica fiber in an extrusion dry-spinning method, has an inclination angle of 60 ° to 85 ° at both ends of winding, and has a winding angle of 60 ° or more. Gel fiber cake in silica fiber manufacturing process characterized by being in the range of less than 90 °