JP2003182766A - Package of polyacrylonitrile fiber bundle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package of a polyacrylonitrile fiber bundle, which prevents fibers of the polyacrylonitrile fiber bundle from being entangled or becoming loose and is capable of being transferred while retaining sheet formability of the fiber bundle when manufactured, and from the fiber bundle of which, high-quality polyacrylonitrile oxidized fibers can be manufactured while preventing trouble from occurring when oxidizing treatment such as the burning and the cutting of the fibers is performed. <P>SOLUTION: The package of a polyacrylonitrile fiber bundle employs a packing container in which a bag having moisture barrier properties is provided. The bundles of the polyacrylonitrile fibers whose moisture regain is 10-45% by mass and whose fiber bundle packing density (dry fiber bundle mass basis) is 0.15-0.45 g/cm<SP>3</SP>are folded back and stacked on one another to be airtightly stored in the bag. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyacrylonitrile fiber bundle package. More specifically, the present invention relates to a polyacrylonitrile-based fiber bundle package which can maintain the uniformity of a polyacrylonitrile-based fiber bundle formed in a sheet shape and can convey the fiber bundle without causing entanglement or separation of fibers.

[0002]

2. Description of the Related Art Polyacrylonitrile-based oxide fibers are not infusibilized, have excellent heat resistance, and have a limiting oxygen index (L
Since it has a high OI) and is flame-retardant, it is processed into a non-woven fabric or a woven fabric and is widely used as a heat-resistant material or a flame-retardant material as a substitute for asbestos.

The polyacrylonitrile oxide fiber can be obtained by oxidizing polyacrylonitrile fiber (precursor). Usually, polyacrylonitrile-based fibers are manufactured as a sheet-like continuous fiber bundle. To produce polyacrylonitrile oxide fiber,
Polyacrylonitrile-based fiber bundles (tows) may be continuously sent to the oxidation process line to produce oxidized fibers, but in general, a certain amount of continuous fiber bundles is maintained while maintaining its sheet shape. It is packed and transported, and then oxidized.

[0004] Examples of packaging forms for carrying a continuous fiber bundle include winding on a bobbin and shaking off on a pallet or container. In the case of winding on a bobbin, a heavy bobbin has to be rotated at a high speed, which requires equipment cost, and therefore, it is widely adopted to be dropped onto a container or the like.

[0005] However, although the cost of dropping the container into a container is low, the tow is scattered,
Alternatively, there is a problem that the fibers of the precursor are easily entangled on the surface that has been shaken off. If the fibers are broken or entangled, the oxidation process in the next step becomes difficult.

Disturbance of fibers in the polyacrylonitrile-based fiber bundle packed in a packaging container such as a container (fiber dislocation and entanglement) causes winding around a roller in the oxidation step. In addition, the disorder of the fiber lowers the shape retention of the polyacrylonitrile fiber bundle at the start-up part which is a pre-step of the oxidation step, excessive convergence of the fiber bundle (higher density) and deformation of the fiber bundle (so-called Toe shift), and fluff (so-called guide fluff) is generated by rubbing between the guide and the fiber bundle.

Further, the turbulence of the fibers causes heat accumulation, combustion and cutting of the fibers in the oxidation furnace. Polyacrylonitrile-based oxidized fiber, a cyclic structure is formed in the polymer by oxygen bonding to the fiber during the oxidation treatment, this structural change is an exothermic reaction, polyacrylonitrile-based fiber bundle in the oxidation furnace accumulates heat, Accelerate burning and cutting. Therefore, in order to obtain a high quality polyacrylonitrile-based oxidized fiber, it is necessary to prevent the fiber from being disturbed and suppress the heat storage of the polyacrylonitrile-based fiber bundle in the oxidation treatment step, and to control the temperature to an appropriate temperature.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to prevent entanglement and dislocation, which are disturbances of fibers of a polyacrylonitrile fiber bundle, to maintain the sheet shape of the fiber bundle at the time of production, and to perform the oxidation treatment. Another object of the present invention is to provide a polyacrylonitrile-based fiber bundle packaging body capable of preventing troubles such as burning and cutting of the fiber.

[0009]

Means for Solving the Problems As a result of intensive studies by the present inventor, if a water content and a packing density at the time of filling a polyacrylonitrile fiber bundle are set within a certain range to form a package, The inventors have found that it is possible to prevent the entanglement and dislocation of the fiber bundle and maintain the sheet shape of the fiber bundle, and have completed the present invention.

The present invention which achieves the above object is as follows.

[1] The moisture barrier bag of the packaging container having the moisture barrier bag inside has a moisture content of 10 to 45% by mass and a fiber bundle packing density (dry fiber bundle mass basis) of 0.15.
A polyacrylonitrile-based fiber bundle package in which polyacrylonitrile-based fiber bundles of 0.45 g / cm ³ are folded back and stacked in an airtight manner.

[2] The folding stroke of the fiber bundle is 0.
The polyacrylonitrile fiber bundle packaging body according to [1], which has a stroke angle of 5 to 2.5 m and a stroke angle of 0.5 to 5 degrees.

[3] The fineness per fiber of the fiber bundle is 0.3 to 2.5 dtex, and the total fineness per bundle of fiber is 1.0 × 10 ^{5 to} 1.2 × 10 ⁶ dtex. The polyacrylonitrile-based fiber bundle package according to [1] or [2].

[4] The ratio of the fiber bundle packing density (based on the dry fiber bundle mass) to the total fineness per fiber bundle is 2 × 10 ⁻⁷
The polyacrylonitrile fiber bundle package according to any one of [1] to [3], which has a size of 3 × 10 ⁻⁶ .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The polyacrylonitrile-based fiber bundle package of the present invention (hereinafter simply referred to as a package) has a moisture content at the time of packaging of 10 to 45% by mass and is filled with a fiber bundle based on the dry fiber bundle mass. Density (hereinafter, simply referred to as packing density) is 0.15
It is characterized in that it is 0.45 g / cm ³ . If the packing density is less than 0.15 g / cm ³ , transportation cost is high,
In addition, the fiber bundles are biased during transportation. On the other hand, when the packing density exceeds 0.45 g / cm ³ , the sheet shape of the polyacrylonitrile-based fiber bundle is difficult to hold due to the weight of the fiber, and the fiber becomes entangled. Further, if the water content during packaging is less than 10% by mass, the convergence of the polyacrylonitrile-based fibers with each other deteriorates and the polyacrylonitrile-based fibers tend to come apart. If the moisture content at the time of packaging exceeds 45% by mass, the moisture content is too large to be used as it is, and drying is required, which is not preferable.

The moisture content of the package can be adjusted within the above range by producing a polyacrylonitrile fiber, squeezing the fiber bundle with a nip roller or the like, and adjusting the degree of drying in the drying step. it can.

The polyacrylonitrile fiber after the manufacturing process is discharged as a sheet-shaped polyacrylonitrile fiber bundle. In order to make a package, the discharged polyacrylonitrile fiber bundle is kept in a sheet form in a container,
Shake off onto a wire mesh paltainer.

The packing density of the package can be controlled within the above range by adjusting the weight of the polyacrylonitrile fiber bundle pressed from the top after being shaken off.

FIG. 1 is a schematic plan view showing a state where a polyacrylonitrile fiber bundle 4 is packed in a packing container 2.

The stroke (folding length L) of the polyacrylonitrile fiber bundle 4 at the time of shaking off is from 0.5 to
It is preferably 2.5 m. Stroke is 0.5m
If it is smaller, the fiber bundle tends to come apart,
If it exceeds 2.5 m, the fibers of the fiber bundle tend to be entangled with each other.

Further, at the time of shaking off, the folding angle formed by the polyacrylonitrile fiber bundle 8 before folding and the polyacrylonitrile fiber bundle 10 after folding in the folding portion 6 of the polyacrylonitrile fiber bundle 4. Two
It is preferable that 1/2 of α (stroke angle α) is 0.5 to 5 degrees. By providing such a stroke angle and folding back, it is possible to prevent the fibers from being entangled during transportation, and to make the startup smooth when performing the oxidation process in the next step. If the stroke angle is less than 0.5 degrees, the folded portion of the polyacrylonitrile fiber bundle tends to be bulky, and the fiber bundle tends to come apart, and the fibers tend to become entangled at the time of start-up in the next step. Stroke angle is 5
If it exceeds the limit, it is difficult to uniformly pack the fiber bundle in the packaging container when it is made into a package, so that the fiber tends to be biased during transportation, and the sheet shape of the polyacrylonitrile fiber bundle tends to be damaged. There is.

In the package of the present invention, a bag having a moisture barrier property is installed inside a packaging container such as a container in which the polyacrylonitrile fiber bundle is shaken off, and the polyacrylonitrile fiber bundle is filled and then sealed. The water content of the acrylonitrile fiber bundle is kept within the above range.

As the material of the moisture barrier bag, polyethylene, polypropylene, polyester and the like can be mentioned, with polyethylene being preferred.

The package of the present invention preferably has a fineness of 0.3 to 2.5 dtex per fiber of the fiber bundle. If the fineness is less than 0.3 dtex, fluffing is likely to occur due to rubbing of the guide or roller surface during the process. Further, when the fineness exceeds 2.5 dtex, the fiber bundle is likely to come apart.

Further, the package of the present invention preferably has a total fineness of 1.0 × 10 ^{5 to} 1.2 × 10 ⁶ dtex per bundle of fibers. The total fineness per one fiber bundle is defined by a value obtained by multiplying the fineness of a single fiber by the number of fibers in one bundle. The total fineness per bundle of fibers is 1.0 × 10 ⁴ dtex
If it is less than the above, the width of the fiber bundle is narrowed due to the influence of tension during the process, and heat is easily stored and cut during the oxidation process. 1.2
When it exceeds x10 ⁶ dtex, the fibers are likely to be dispersed, and it tends to be difficult to control the thickness uniformity in the width direction.

The packing of the present invention has a packing density (g / cm ³ ).
And the ratio of total fineness (dtex) per fiber bundle is 2 × 1
It is preferably 0 ^{−7 to} 3 × 10 ⁻⁶ . If it is less than 2 × 10 ⁻⁷ , fibers are likely to be scattered. If it exceeds 3 × 10 ⁻⁶ , heat storage and cutting are likely to occur during the oxidation step.

[0027]

The present invention will be described in more detail with reference to the following examples. The water content and packing density in the examples were determined by the following methods.

[Moisture Content] A unit length (1 m) fiber bundle was randomly sampled from the polyacrylonitrile fiber bundle packed in the package and dried at 120 ° C. for 2 hours. The water content of the fiber bundle was determined.

[Filling Density] The mass of the polyacrylonitrile fiber bundle packed in the package is measured, the mass of the dry fiber bundle is calculated from the moisture content obtained by the above method, and the mass is divided by the volume of the package to fill. The density was used.

Example 1 Moisture-added polyacrylonitrile fiber bundle (fineness: 1.6 dtex, number of single fibers: 312,000) was continuously squeezed with a nip roller to adjust the water content to 34% by mass. . Then, after filling the wire mesh partitioner (bottom width 1.1 m × length 2 m, height 1.2 m) with a moisture barrier polyethylene bag installed at a stroke of 1.9 m and a stroke angle of 1.5 degrees, Closed (packing density 0.20 g / cm ³ , total fineness per bundle of fibers 4.99)
× 10 ⁵ dtex, packing density / total fineness per fiber bundle 4 × 10 ^-7 ). After being stored at 25 to 30 ° C. for 10 days, it was transported and subjected to an oxidation treatment in an oxidation furnace. When the package was opened and started up on a creel and oxidation treatment was continuously performed in air at a temperature of 250 ° C., there was no deviation between fibers of the fiber bundle at the start-up part, and no fluff was generated in the guide part. It was In addition, high quality polyacrylonitrile oxide fiber could be obtained without fiber cutting due to heat storage in the oxidation furnace.

Examples 2 and 3, Comparative Examples 1 and 2 Polyacrylonitrile fiber bundle packages shown in Table 1 were operated in the same manner as in Example 1 except that the water content and packing density of the polyacrylonitrile fiber bundle were different. I made it and evaluated it. The results are also shown in Table 1.

[0032]

[Table 1]

Comparative Example 3 A polyacrylonitrile fiber bundle (0.9
The water content of dtex and the number of single fibers of 90,000) was continuously squeezed with a nip roller to adjust the water content to 35% by mass. After that, a wire mesh partitioner (bottom width 1.1 m x length 2 m, in which a moisture barrier polyethylene bag was installed,
The height 1.2 m) was filled with a stroke of 1.9 m and a stroke angle of 2.0 degrees, and then sealed (filling density 0.50 g
/ Cm ³ , total fineness per bundle of fibers 0.81 × 10 ⁵ dt
ex, packing density / total fineness per fiber bundle 6.1 × 10
^-6 ). After being stored at 25 to 30 ° C. for 10 days, it was transported and subjected to an oxidation treatment in an oxidation furnace. When the package was opened and stood up on a creel and continuously subjected to an oxidation treatment in air at a temperature of 250 ° C., the fibers of the fiber bundle were displaced at the stood up part, and fluff was generated at the guide part. Further, fiber cutting due to heat storage occurred in the oxidation furnace.

[0034]

According to the polyacrylonitrile fiber bundle packing of the present invention, the polyacrylonitrile fiber bundle is prevented from being entangled or broken and the sheet shape of the fiber bundle at the time of production is maintained to obtain the polyacrylonitrile fiber bundle. Since it can be transported, troubles such as burning and cutting of the fiber at the time of the next step of oxidation treatment can be prevented, and high quality polyacrylonitrile-based oxidized fiber can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an example of a polyacrylonitrile fiber bundle package of the present invention.

[Explanation of symbols]

2 packing containers 4 Polyacrylonitrile fiber bundle 6 Folding part 8 Polyacrylonitrile fiber bundle before folding back 10 Polyacrylonitrile fiber bundle after folding back L turn back length

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3E067 AA24 AB99 BA05C BA12B                       BB07C BB11C BB15B BB16B                       CA05 FC01                 3F058 AA01 AB03 AC02 EA01 EB00

Claims (4)

[Claims] 1. A moisture barrier bag having a moisture barrier bag inside, wherein the moisture barrier bag has a moisture content of 10 to 45% by mass and a fiber bundle packing density (dry fiber bundle mass basis) of 0.15 to 0. ．
A polyacrylonitrile-based fiber bundle package in which a polyacrylonitrile-based fiber bundle having a weight of 45 g / cm ³ is folded back and stacked to be hermetically stored. 2. The folding stroke of the fiber bundle is 0.5 to
The polyacrylonitrile fiber bundle packing body according to claim 1, which has a stroke angle of 0.5 to 5 degrees at 2.5 m. 3. The fineness per fiber of the fiber bundle is 0.3 to
It is 2.5 dtex, and the total fineness per bundle of fibers is 1.
The polyacrylonitrile-based fiber bundle packaging body according to claim 1 or 2, which has a density of 0 × 10 ^{5 to} 1.2 × 10 ⁶ dtex. 4. A fiber bundle packing density (based on a dry fiber bundle mass)
And the total fineness per fiber bundle is 2 × 10 ^{−7 to} 3 × 1
The polyacrylonitrile-based fiber bundle packaging body according to any one of claims 1 to 3, which is 0 ^-6 .