JPH01103925A - Gel fiber cake in silica fiber producing stage - Google Patents

Abstract

PURPOSE:To remarkably improve the unraveling property of a strand and to increase the production yield of a silica fiber by a sol-gel process by limiting the tilt angle of both ends of the take up winding of a gel fiber cake and the leasing angle of the winding when the silica fiber is produced. CONSTITUTION:In a silica fiber producing stage, a gel fiber cake 3 made of a gel fiber 1 as a precursor of a silica fiber produced by extrusion and dry spinning is formed. The tilt angle alpha of both ends of the winding of the cake 3 is 60-85 deg. and the leasing angle beta of the winding is 60-<90 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a gel fiber cake in a silica fiber manufacturing process.

[Prior Art] In the silica fiber production technology using the sol-gel method to which the present invention relates, fibers in a gel state (hereinafter referred to as gel fibers), which are precursors of silica fibers, are produced by extruding from a spinning solution containing organic silicon and using a dry spinning method. )
form.

In general, various methods are known for receiving fibers formed by continuous spinning or sampling, taking into consideration the physical properties of the fibers, means of transporting the fibers to the next process, and the like.

In the glass fiber harvesting process using the conventional melting method,
After applying a sizing agent to the filaments coming out of the bushing, they are combined into a strand, which is cradled in a paper or plastic tube and wound up. In addition to the yarn harvesting process using the melting method, a wound product of strands immediately after yarn harvesting or spinning is called a forming package or cake.

Fiber (hereinafter sometimes referred to as monofilament)
When winding a strand consisting of multiple strands into a tube,
There is a method of winding the traverse guide and the tube while separating the traverse guide, and a method of winding the traverse guide and the tube very close to each other and keeping the distance constant while holding down the wound strand with a touch roll.

When the traverse guide and the tube are wound apart from each other, the return of the strands at both ends of the tube is delayed due to the inertial force acting on the strands, so that a package is likely to be wound up with the ears bulging. When unwinding the strands from this package in the next process, if you try to guide the threads by taking them out, the strands will rub against each other at least at both ends, making it difficult to unwind at high speed. In addition, vertical removal requires a rotating shaft or rotating device for the package.

In addition, the method using a touch roll described above is not suitable for winding fibers that are weak against friction or fibers that are weak against bending at high speed, such as the gel fiber of the present invention, because the strand is always held down by the touch roll. .

On the other hand, Japanese Patent Publication No. 57-20409 discloses a method for producing refractory metal oxide fibers in which a strand of raw continuous fibers formed by extruding a viscous solution or dispersion of a metal compound from a spinneret is deposited on a moving mesh belt. It is disclosed that the material is then continuously sent to the next step, which is a firing step.

In addition to the above-mentioned method, as a means to continuously feed fibers with relatively low strength before firing into the firing process, as in the case of pitch-based carbon fibers, while drawing a regular figure 8 shape in the coiler territory, Deposition methods are also known.

However, silica gel fibers react with moisture in the air and the polycondensation reaction further progresses, causing the amount of shrinkage to increase over time. If strands made of shrinkable fibers are deposited in a free state, the difference in the amount of shrinkage of each fiber will cause loops to be formed in the fibers during the deposition process, causing damage during and after firing. This also results in poorly aligned strands.

In the technology for producing silica fibers by the sol-gel method to which the present invention relates, spun gel fibers are fired. In order to remove the organic components contained in the gel fibers during this firing process, perform sintering efficiently, and obtain high-strength silica fibers, it is essential to apply a certain tension to the fibers during the firing process. It is.

It is desirable that the above-mentioned tension applied to the gel fiber or a strand consisting of a plurality of gel fibers be as large as possible so as not to cause the gel fiber or its strand to break. Application methods include a dancer roll method and a friction method.

[Problems to be Solved by the Invention] The present invention uses a traverse guide to wind the gel fiber or a strand made of a plurality of gel fibers onto a tube spaced apart from the traverse guide to form a gel fiber cake. This is an attempt to solve the above-mentioned problems caused by the forming method.

[Means for solving the problem] The present invention was made to solve the above-mentioned problem, and is made of gel fiber, which is a precursor of silica fiber in the extrusion dry spinning method, To provide a gel fiber cake characterized in that the inclination angle is in the range of 60° to 85°, and the winding cradling angle is in the range of 60° or more and less than 90°.

FIG. 1 is an explanatory sectional view when the gel fiber cake is cut along a plane including the winding rotation axis (equivalent to the symmetrical axis of the tube), and FIG. 2 is a partially enlarged view of FIG. 1.

In FIG. 1, a is the inclination angle, and in FIG. 2, the angle β formed by the axis of symmetry of the fiber or strand and the tube is the winding winding angle.

When gel fibers or strands are wound onto a tube using a traverse guide and kept at a distance from the traverse guide, the formed gel fiber cake tends to have a bulging shape at both ends, making it difficult to unwind the wound product. When doing so, there are many opportunities for the fibers or strands to rub against each other, and damage is likely to occur. Accordingly, the present invention provides a gel fiber cake having both ends tapered as shown in FIG. Such a shape can be obtained by adjusting the traverse width so that it decreases over time from the start of winding.

In the present invention, the angle of inclination is preferably in the range of 60° to 85°. If it is larger than 85°, the inclination effect will be poor, and if it is smaller than 60°, the winding weight per tube will be too small, causing problems in terms of production efficiency.

Furthermore, the gel fiber reacts with moisture in the atmosphere, undergoes a polycondensation reaction, and shrinks. Therefore, the overlapping density of gel fibers is one of the factors that determines the reaction between gel and water. In fact, if the angle is larger than 85°, the overlapping density of gel fibers at both ends becomes too large compared to that at the center, resulting in a difference in the amount of contraction of gel fibers.
It was found that the occurrence of loops and fluffing increased, degrading the quality of the silica fiber.

If it is smaller than 60°, on the contrary, the overlapping density of the gel fibers at both ends decreases, making it easier to react with moisture in the atmosphere, and shrinking more than at the center. In this case, although the unwinding property was relatively good, it was found that it was difficult to remove the organic matter contained in the gel fiber during the firing process, and the silica fiber turned black.

The outside method was mentioned earlier as a method for unwinding the strand from the cake, but this is because the gel fiber shrinks by about 2% after winding, so the outside method, which does not involve removing the tube, is less problematic than the inside method. This is taken into consideration.

Although the invention provides a cake that is particularly suitable for the scraping process, the invention is not limited to the scraping process.

Further, tension is applied to the strand during firing using a dancer roller or friction. The tension to be applied is about 50 to 80% of the tensile strength of the gel fiber.
It corresponds to the degree. In order to improve the unwinding property of the gel fiber strand under these conditions, the winding winding angle is set in the range of 60° or more and less than 90°, preferably 70° to 80°. A cradle angle of 90° means a package in which the strands are wound in parallel, and due to the large shrinkage after winding that is unique to gel fibers, the inner strand and the outer strand overlap tightly, making it smooth and free from damage. It becomes impossible to unwind strands that are not present. Furthermore, if the cradling angle is less than 60°, the gel fibers will be seriously damaged by the traverse guide, causing breakage and fluffing of the fibers making up the strands.

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

Number of fibers making up the strand: 120 Fiber diameter (long diameter of oval or treetop circle): Average 1
3μm Winding speed: 150m/min Winding tube diameter: 300mm Traverse width: Maximum 254mm Table 1 Table 2 Note (2) Monofilament breaks frequently when turning with the traverse guide.

(3) The monofilament may break when turning with the traverse guide.

(4) No monofilament breakage.

[Effects of the Invention] The present invention has the effect of significantly improving the unwinding properties of the strand. In particular, since it is possible to reduce frictional damage between gel fibers or strands during unwinding, it is effective to obtain high-strength silica fibers with less fuzz. In addition, the low fluff and high strength are effective in improving the yield through the silica fiber manufacturing process using the sol-gel method.

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

Furthermore, in the gel fiber cake of the present invention, the contraction that is unique and unavoidable to gel fibers is uniformly realized throughout the gel fibers constituting the strand, and as a result, there is an effect that the occurrence 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.

Furthermore, according to the present invention, it is possible to obtain a silica furper of excellent quality that is not colored black during the firing process.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view taken along a plane including the winding axis of the gel fiber cake, and FIG. 2 is an explanatory diagram of the cradling angle. 1...Strand, 2...Tube, 3...Gel fiber cake, a...Inclination angle, β...Twill angle, A-...Maximum value of traverse width, B-...Traverse width The minimum value of Engraving of the drawings (contents (no changes)) Article 1 [3 Procedural amendments against illusion February 1986 date]

Claims (1)

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