JPS5936716A - Preparation of precursor yarn for carbon fiber - Google Patents

Abstract

PURPOSE:To obtain precursor yarn for carbon fiber providing improved properties for separated single filament yarn after being burned, by bringing acrylic yarn after spinning and drawing into contact with a great quantity of water in counter current flow with making it run along the outer peripheral face of a basket roller having a large number of bored through-holes. CONSTITUTION:In a water washing process to prepare precursor yarn for carbon fiber by spinning a solution of acrylic polymer, drawing it, washing it with water, drying it and making it dense, as a basket roller equipped with through- holes having 5-10mm. diameter on the surface of the roller, having 30-50% porosity, is positively rotated in a water bath, and the spun and drawn yarn is wound round the outer peripheral face of the roller in a widen state of <=5,000 denier/cm yarn density, made to run 15-150m/min, water is made to flow in counter current flow in a mass velocity of 8-20 times the travel speed of the yarn so that the yarn is washed. The washing water has preferably <=5mumho/cm electric conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing carbon fiber precursor yarn, and more specifically, it has high water washing efficiency, and thus improves the splitting property of the yarn when splitting after firing the precursor yarn. The present invention relates to a method for producing carbon fiber precursor yarn, including a method for good water washing.

Carbon fiber is obtained by firing its precursor yarn at high temperature, but the carbon fiber precursor is obtained by spinning a solution of polyacrylonitrile or cellulose in a coagulation bath, washing with water, stretching or drawing, washing with water, and then drying and densifying it. Manufactured through.

In wet spinning, in which a polymer solution is spun in a bath, a water washing process to remove the polymer solvent is important, and conventionally 4. Various methods of washing with water have been tried.

For example, when manufacturing acrylic fiber tow for clothing, a so-called vibro washing machine is used in the tow washing process, which has a basket roller with many holes on the roller surface and a petal-shaped runner that rotates inside the basket roller. It is described in Japanese Patent Publication No. 48-28969 that water washing efficiency can be increased by However, the carbon fiber precursor yarn targeted by the present invention usually has 1,000 to 10,000 filaments, which is considerably smaller than the yarn used in the production of staple fibers for clothing, which is generally applied with vibrator mouth washing. - For basic fibers, it is required to have far fewer so-called yarn disturbances such as fuzz and loops, so it has not been possible to wash properly with water using known methods.

The present inventors conducted repeated studies in pursuit of an excellent water washing method for carbon fiber precursor yarns, and as a result, they arrived at the present invention.

Therefore, an object of the present invention is to produce a carbon fiber precursor yarn that includes a water washing method that has high water washing efficiency and produces carbon fibers with good splitting properties when splitting after doubling and firing. The present invention provides a method.

That is, in the present invention, when manufacturing a carbon fiber precursor yarn by spinning, stretching, washing with water, and drying an acrylic polymer solution, through-holes with a diameter of 5 to 10 mm are formed on the roller surface with a porosity of 60 mm.
A basket roller provided at ~50% is actively rotated in a water bath, and the yarn after spinning and drawing is expanded to a yarn density of 5000 denier/c1n or less and wound around the outer peripheral surface of the basket roller. The thread is run at a speed of 150 tn/min, and the water bath is washed with water having an electrical resistivity of 5 μV/an or less at a mass speed of 8 to 20 times that of the running thread. This is a method for producing carbon fiber precursor yarn.

The present invention will be specifically explained below.

The basket roller that can be used in the water washing process of the present invention has many holes with a diameter of 5 to 10 mu on its surface.
The area of the hole relative to the area of the roller hole arrangement area, that is, the open area ratio is 60
~50%, and a water washer with only a simple basket roller may be used, or a vibro water washer with a petal-shaped runner inside the basket roller may be used.

When washing thin threads such as carbon fiber precursor fibers with water, the basket roller needs to rotate at the stacking edge so as not to create resistance to the running of the threads.

In the case of a vibro washing machine, the runner is normally rotated at high speed and small vibrations are applied to the water, but in the case of the present invention, the rotation of the runner is not necessarily necessary.
There is no need to rotate it at all. If the rotational speed of the runner becomes too high, the thread washing effect will improve, but
Sufficient care must be taken when rotating the runner, as the threads may become disordered, resulting in excessive filament tangles and thread breakage. Further, as long as the conditions of the present invention are satisfied, the washing effect is sufficient even if the runner is stopped, and in this case, this is a preferable method because the yarn is less disturbed. The diameter of the through hole on the surface of the basket roller is also related to the width of the yarn, but 5
If the length is less than 10 m, the washing efficiency will be poor, and if the length exceeds 10 m, the threads will fall into the holes, which is not preferable.

If the porosity ratio is less than 130%, washing with water will not be sufficient, and 50%
Exceeding this will cause problems with the strength of the roller surface. The thread to be subjected to the water washing step is preferably a thread after being drawn, but a thread before being drawn may also be used.

The density of the yarn wound around the outer peripheral surface of the basket roller, that is, the total denier per unit width of the yarn is 5000 denier/c.
The running speed of the yarn passing through the washing bath, that is, the circumferential speed of the basket roller, must be 15 to 150772/In1n. If it is less than vn/m, the productivity will be low, and if it exceeds 1 sotn7-tn, the yarn will be unfavorably disordered. Number of basket rollers, t, b
When washing the yarn with water, there is no particular limitation on whether or not the basket rollers are used in an upside-down manner, but usually 2 to 20 basket rollers are used.
Preferably 4~. There are 16 units.

In the present invention, it is necessary to flow water countercurrently in the washing bath to the running yarn. The mass velocity of the countercurrent water needs to be 8 to 20 times the mass velocity of the yarn from the viewpoint of washing efficiency and economic efficiency.

The water washing bath can be divided into multiple stages for multi-stage water washing, - at this time, the countercurrent water is sent to the final stage water washing bath,
A method can be adopted in which the flow is made to flow countercurrently to the front washing bath. The quality of the water to be flowed countercurrently needs to have an electrical resistivity of 5 μv/ctn or less so as not to reduce the yield and strength characteristics in the flameproofing process.

The present invention can achieve its intended purpose only when all two conditions are satisfied. In other words, when applying the conditions conventionally known in the manufacturing process of acrylic fibers for clothing, it was not possible to obtain excellent carbon fiber precursor yarns, but by combining special conditions as in the present invention, It is thought that these synergistic effects are exerted, resulting in two effects: excellent water washing effect and carbon fiber splitting properties.

The present invention will be specifically explained below using Examples.

Example 1 Using a spinning machine with 6,000 holes and 18 spindles, a dimethyl sulfoxide solution of an acrylic polymer was wound at 180 m/min, and spinning was carried out under conditions such that the single yarn denier was 1 denier.

The composition of the spinning bath was 45/15 dimethyl sulfoxide/water.
Parts by weight, the temperature was still 60°C.

Each spun 6000 filaments are separated by 3
[ ] After dividing into DO filaments, the filaments were stretched 5.0 times in a stretching bath mainly containing hot water at 90°C. Next, it was introduced into an 8-stage multi-stage water washer equipped with a vibro water washer and washed with water.

The vibro water washer has a actively driven basket roller on the outer layer, and its surface has holes with a diameter of 8 mm and a perforation ratio of 40 mm.
%, and still has a petal-shaped runner (rotor) inside the basket roller.

When washing with water, the circumferential speed of all basket rollers is 69 m.
/win, and the washing water was supplied to the final bathtub with ion-exchanged water with an electrical resistivity of 5 μV/cm or less at a mass rate of 10 times the mass of the polymer, and the threads were sequentially flowed back to the previous washing process. It was carried out by countercurrent flow to the column.

Each yarn in the water washing process was 7800 denier, and the width of the yarn after passing through each vibro washing machine was on the 1.8 to 2.0 side. Therefore, the density of the yarn when washed with water is 4500 ~
It was 3900 denier/cln.

After washing with water in this way, the yarn is coated with an oil agent, dried and densified using an o-ra, and then stretched to 2.6 times in a high-pressure steam tube with a labyrinth-sealed end. It was heat-treated with a drum roller heated to about 200° C., and the oil was wound up.

The fluff (converted to 3,000 filaments) of the obtained yarn was measured before being opened, and found to be extremely low at 0.8 fuzz/m, resulting in a high-quality yarn.

Furthermore, the residual amount of solvent obtained by treating the yarn with hot water and measuring the extracted liquid by gas chromatography was 0.012 per yarn weight.
% and was at a low level.

Example 2, Comparative Example 1 The yarn was wound in the same manner as in Example 1, except that the pore diameter and the aperture ratio of the basket roller were changed as shown in Table 1. Table 1 shows the results of measuring the number of fuzz and the amount of residual solvent for the obtained yarn.

Table 1 *) The porosity was too large, causing distortion on the roller surface.

Example 3, Comparative Example 2 After spinning and drawing in the same manner as in Example 1, the yarn width was changed using a guide, and the yarn was introduced into a vibro washing machine and washed with water. A thread width adjustment guide was provided for each of the 8 vibro washing machines arranged in series, and the processes after Atonobe Oki were carried out under the same conditions as in Example 1.

Table 2 shows the results of measuring the amount of residual solvent in the obtained yarn.

Table 2 Example 4, Comparative Example 3 The yarn was wound in the same manner as in Example 1, except that the amount of ion-exchanged water supplied to the 8th stage water washing bath relative to the amount of yarn passing through was changed.

If the amount of water was too small relative to the amount of yarn passing through, the amount of residual solvent in the resulting precursor yarn would be high, and the carbon fibers after firing would not have sufficient strength.

Table 6 shows the amount of solvent remaining in the yarn.

Table 6 Patent applicant Toshi Co., Ltd. Company procedures
Amendment 1. Name of the invention: Method for producing carbon fiber precursor thread 5. Person making the amendment Relationship to the case Patent application Life Location 2-2-4 Hikibashi Muromachi, Chuo-ku, Tokyo Date of amendment order Vol. 5 Number of inventions increased by amendment None Amendment in column 7 of “Detailed description of invention” (1) The scope of claims is amended as shown in the attached sheet.

(2) Page 1, lines 19 to 20 "Thus, the precursor thread" is corrected to "and the precursor thread."

(3) Page 4, lines 2 to 4: At a power purchase rate of 18 to 20 times, water with an electric specific resistance of 5 μV/m or less -1 to water at a mass rate of 18 to 20 times. and correct it.

(4) Page 6, line 20 to page 7, line 1 [5μV/
Is it necessary to have an electrical resistivity of on or less? -1 as “
5μU/. It is preferable to have the following electrical conductivity.

” he corrected.

(5) On page 7, line 18, "45/15 parts by weight," is corrected to "45155 parts by weight, 1."

(6) Page 8, line 11, “Electrical specific resistance 5/JV/QIIJ”
Correct with ti/CIIIJ.

Attachment - 8 Claims When producing carbon fiber precursor yarn by spinning, stretching, and washing an acrylic polymer solution, and drying and densifying it, p-holes with a diameter of 5 to 1O- are opened on the roller surface. A basket roller provided at a ratio of 30 to 50% is actively rotated in a water bath, and the yarn after spinning and drawing has a yarn density of 5000 denier/, 1
5. Wrap it around the outer circumferential surface of the basket roller in the expanded state to 15 to 15 liters. When running at Om/mn.

The carbon machine HI is characterized in that the water bath is washed with water at a mass velocity of 8 to 20 times that of the traveling yarn.
′Method for producing precursor strings.

Claims (1)

[Claims] When the acrylic polymer solution is spun, stretched, washed with water, and then dried and densified to produce a carbon fiber precursor yarn, through holes with a diameter of 5 to 10 mm are provided on the roller surface with a porosity of 30 to 50%. The basket rollers were actively rotated in a water bath, and the yarn density after spinning and drawing was adjusted to the yarn density.
The yarn is wound around the outer circumferential surface of the basket roller in a state where it is spread out to a size smaller than the length of the thread, and is run at a speed of 15 to 150 tn/min, and the water bath is coated with an electrical resistivity of 5 p at a mass speed of 8 to 20 times that of the running yarn. A method for producing carbon fiber precursor yarn, which comprises washing the yarn with water of V/crn or less in countercurrent flow.