JPH09302594A - Production of vulcanized fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of zinc chloride removing process with virtually no influence on the diffusion of the zinc chloride in vulcanized fibers even if washing water is agitated because the above diffusion represents a rate-determining step during the zinc chloride removing process. SOLUTION: The vulcanized fibers are obtained by applying the following processes successively: one or more sheets of base paper is immersed in a concentrated aqueous solution of zinc chloride to swell, dissolve and gelatinize the surface of the base paper; when two or more sheets of base paper are to be used, these sheets are mutually laminated; the base paper is subjected to zinc chloride removing process by using a washing liquid; and the resultant sheet(s) of base paper is dried and finished. In this case, a part or the whole of treatment process for the zinc chloride removal using the washing liquid is carried out as follows: an apparatus provided with vibratory blades fixed irrotatably in a single tier or tiers on the axially vibratory shaft is put into the washing liquid in a zinc chloride removal tank and vibrations are applied to the blades with the number of vibrations of 10-60Hz and amplitude of 2-30mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing vulcanized fiber, and more particularly to a method for producing vulcanized fiber which can enhance the efficiency of the dezincification process using a cleaning solution as compared with the conventional method. Vulcanized fiber is a natural fiber material with excellent mechanical strength and has workability such as punching, bending, press molding, impact resistance, abrasion resistance, oil resistance,
It is a material with excellent electrical insulation.

[0002]

2. Description of the Related Art In the process of manufacturing vulcanized fiber, a process of immersing a base paper in a concentrated aqueous solution of zinc chloride to swell, dissolve and gelatinize the surface of the base paper, and then to remove zinc chloride with a washing liquid to stop the dissolution reaction The process consists of a zinc chloride process followed by a drying and finishing process. In addition, since many vulcanized fiber industrial products are thick, and in order to completely make vulcanized fiber, thin base paper is usually swelled, melted, and glued to form multiple layers of base paper, followed by dezincification chloride. Then dry and finish, but 1
Naturally, the vulcanized fiber made of one sheet of base paper,
No laminating step is required.

[0003]

In the process of dezincification of vulcanized fiber, if the vulcanized fiber is directly immersed in water, an excessive osmotic pressure causes an excessive osmotic pressure due to a large difference in concentration between zinc chloride in the vulcanized fiber and water. It occurs inside the laminate and causes a peeling phenomenon on the laminate surface, resulting in loss of product value. Therefore, in order to prevent such a phenomenon in the actual manufacturing process, first dip it in a relatively low concentration zinc chloride aqueous solution within a range that does not cause delamination of the laminated surface, and then gradually dip it in a lower concentration zinc chloride aqueous solution. Then, a step of finally immersing in water to reduce the zinc chloride content in the vulcanized fiber to a predetermined amount or less is taken. This series of steps is called a dezincification step.

The vulcanized fiber manufacturing process includes a continuous system and a batch system. In the continuous system, the process of immersing the base paper in a concentrated aqueous solution of zinc chloride, dezincification and drying is continuously performed. In the batch method, the base paper is dipped in zinc chloride, wound around a drum, cut to a predetermined thickness, cut, and dezincified and dried for each lot.
Usually, the continuous method is often used, but when the thickness is extremely large, the batch method may be used.

The dezincification step takes the longest time in the manufacturing process of vulcanized fiber, and the thicker it takes, the longer it takes. Dezincification of vulcanized fiber is dominated by solid diffusion in the porous fiber material, and it is possible to promote the diffusion of zinc chloride in the vulcanized fiber to some extent by increasing the temperature of the cleaning solution in the dezincification tank. However, since the zinc dechlorination process uses an extremely large amount of cleaning liquid, raising the temperature of such a large amount of cleaning liquid requires enormous energy costs, and zinc chloride is still present in the vulcanized fiber in the early stages of dechlorinating zinc. In the remaining region, the dissolution reaction of the cellulose constituting the vulcanized fiber further progresses due to the temperature increase, which adversely affects the product quality, which is not preferable.

It is also conceivable to stir the washing water in the dezincification tank with an ordinary rotary vane type agitator, but since diffusion of zinc chloride in the vulcanized fiber is the rate-determining step in dechlorination zinc. Even if the washing water is stirred, it hardly affects the diffusion of zinc chloride in the vulcanized fiber and has little effect of improving the efficiency of dezincification. Therefore, an object of the present invention is to solve the above problems in the conventional vulcanized fiber manufacturing process and improve the efficiency of the dezincification process.

[0007]

The method for producing vulcanized fibers according to the present invention comprises a step of immersing one or more base papers in a concentrated aqueous solution of zinc chloride, and swelling, dissolving, and gelatinizing the surface of the base papers. In the method for producing vulcanized fiber by sequentially applying a step of laminating two or more base papers, a step of dechlorinating the base paper with a cleaning solution, a drying and finishing step of the base paper when two or more base papers are used, All or part of the dezincification treatment of the base paper by means of a device in which the vibrating blade plate is fixed to the vibrating shaft that vibrates in the axial direction in one or more stages so that it does not rotate in the washing liquid in the dechlorination zinc tank. Then, put it into the vibrating vane and make it 1
It is performed while giving a vibration of 0 to 60 HZ and a vibration width of 2 to 30 mm.

In the present invention, the apparatus for introducing the cleaning liquid in the dechlorination zinc tank is one in which the vibrating vane plates are non-rotatably fixed to the vibrating shaft vibrating in the axial direction in one stage or in multiple stages, and the vibration frequency is 10 to 10. It is performed by a vibration motor or the like that generates a vibration of 60 Hz, preferably 20 to 40 Hz. Frequency is 10Hz
If it is less than 60 Hz or more than 60 Hz, the effect of promoting dechlorination zinc becomes insufficient. The vibration width of the diaphragm is 2 to 30 m.
m is preferably 10 to 15 mm. If the vibration width is less than 2 mm, the dezincification effect is insufficient, and if it exceeds 30 mm, the shaking of the cleaning liquid in the dechlorination zinc tank becomes violent, and the vulcanized fiber in the cleaning liquid is affected by the shaking of the cleaning liquid. Wrinkles or fractures are likely to occur, which is not suitable.

To produce vulcanized fiber by the method for producing vulcanized fiber of the present invention,
Purified natural cellulose fiber pulp such as cotton pulp and wood pulp, or a conventional paper using a base paper made by mixing inorganic fibers such as carbon fiber and glass fiber and various synthetic fibers depending on the intended use of the final product. The base paper is dipped in a concentrated aqueous solution of zinc chloride to swell, dissolve, and gelatinize the surface of the base paper, and when two or more base papers are used, these base papers are laminated. Next, in the cleaning liquid in the dechlorination zinc tank, in advance, put a device in which the vibrating blade plate is fixed in a non-rotatable manner in one or more stages on the vibrating shaft that vibrates in the axial direction,
The vibrating blade plate has a frequency of 10 to 60 Hz and a vibration width of 2 to 30 Hz.
The vulcanized fiber that has been immersed in the dezincification tank is subjected to dezincification treatment while giving a vibration of mm. Finally, the product is dried and finished by a conventional method. In addition,
The method for producing vulcanized fiber of the present invention can be applied to both the continuous method and the batch method. Further, in the method for producing a vulcanized fiber according to the present invention, the dezincification method using a device in which the vibrating vane is fixed to the vibrating shaft vibrating in the axial direction in a one-stage or multi-stage manner so as to be non-rotatable is used for all dezincification steps. It may be applied or may be applied to a part thereof.

[0010]

The function and mechanism of the present invention are not necessarily clear, but they are presumed as follows. As mentioned above, dezincification of vulcanized fiber is dominated by solid diffusion in the porous fiber material, and even if the cleaning liquid in the dezincification tank is stirred by a normal rotary stirrer, It has little effect on the diffusion of zinc chloride, and as a result, almost no promoting effect of dezincification is obtained. On the other hand, in the present invention, the cleaning liquid in the dezincification tank is provided with a device in which the vibrating blade plate is fixed to the vibrating shaft that vibrates in the axial direction in one or more stages so that the vibrating blade plate is not rotated. Vibration frequency 10-60Hz, vibration width 2-30m
The vibration of the vibrating blade plate is transmitted to the cleaning liquid in the dechlorination zinc tank and then to the vulcanized fiber immersed in the cleaning liquid, and the vulcanized fiber itself vibrates and the porous fiber material is used. This vibration is also transmitted to the zinc chloride aqueous solution that fills the inter-fiber voids in the barrel vulcanized fiber, causing the chloride aqueous solution to finely flow in the inter-fiber voids, resulting in accelerated diffusion of zinc chloride in the vulcanized fibers. It is considered that the specific effect that dezincification is significantly promoted is exhibited.

[0011]

EXAMPLES The present invention will now be described based on examples. The thickness and chlorine content of the test pieces in the examples are measured according to JIS
According to the method specified in C2315.

Example 1 A base paper made of purified natural cellulose pulp was prepared according to a conventional method in a concentrated aqueous solution of zinc chloride (liquid concentration 70 ° Baume, liquid temperature 35).
℃), swelling, dissolving, and gelatinizing the surface of the base paper, and then laminating, and then dezincing zinc treatment by a conventional method,
30 cm × at the stage where the vulcanized fiber still contains a considerable amount of zinc chloride during the dezincification treatment.
Four 30 cm test pieces were cut out. Next, water was filled as a cleaning liquid in an experimental dechlorination zinc bath (volume: 200 liters), and the cleaning shaft was vibrated in the axial direction by 6
A device (product name: super-vibration stirrer α-1 type: manufactured by Nippon Techno Co., Ltd.) in which the stepped vibrating blade plate is fixed in a non-rotatable manner is introduced, and the vibrating blade plate of the device has a vibration frequency of 25 Hz and a vibration width of 15 mm.
Three of the test pieces were put in while applying the vibration of 1. and after 1 hour, 2 hours, and 4 hours, one piece was pulled up. Next, when a total of 4 test pieces including the test piece that was not immersed in the experimental dechlorination tank were dried by a conventional method, all of the 4 test pieces became vulcanized fiber having a thickness of about 1.6 mm. . The chlorine content of the four test pieces was measured, and the obtained results are shown in Table 1.

[0013]

[Table 1]

Example 2 Example 2 is different from Example 1 except that the number of laminated base papers was changed, the vibration frequency of the vibrating blade plate was 35 Hz, the vibration width was 10 mm, and the treatment time in the experimental dechlorination zinc tank was changed. Specimen vulcanized fiber (thickness: about 1.
The chlorine content of 0 mm) was measured, and the obtained results are shown in Table 2.

[0015]

[Table 2]

Comparative Example 1 In Example 1, in the dezincification treatment in the experimental dezincification tank, an apparatus in which 6 stages of vibrating blade plates were non-rotatably fixed to a vibrating shaft vibrating in the axial direction was used. The chlorine content of the test piece vulcanized fiber (thickness: about 1.6 mm) obtained in the same manner as in Example 1 except that it was not used was measured,
The obtained results are also shown in Table 1.

COMPARATIVE EXAMPLE 2 In Example 2, in the dezincification treatment in the experimental dezincification tank, an apparatus in which 6 stages of vibrating blade plates were non-rotatably fixed to the vibrating shaft vibrating in the axial direction was used. The chlorine content of the test piece vulcanized fiber (thickness: about 1.0 mm) obtained in the same manner as in Example 2 was measured except that it was not used.
The results obtained are shown in Table 2.

COMPARATIVE EXAMPLE 3 In Example 1, in the dezincification treatment in the experimental dezincification tank, a device in which 6 stages of vibrating vanes were non-rotatably fixed to the vibrating shaft vibrating in the axial direction was used. Instead, the chlorine content of the test piece vulcanized fiber (thickness: about 1.6 mm) obtained in the same manner as in Example 1 except that the cleaning liquid in the experimental dechlorination zinc tank was stirred using an ordinary rotary blade type stirrer The amount was measured, and the obtained results are also shown in Table 1.

COMPARATIVE EXAMPLE 4 In Example 2, in the dezincification treatment in the experimental dezincification tank, a device in which six vibrating vanes were non-rotatably fixed to the vibrating shaft vibrating in the axial direction was used. Instead, the chlorine content of the test piece vulcanized fiber (thickness: about 1.0 mm) obtained in the same manner as in Example 2 except that the cleaning liquid in the experimental dechlorination zinc tank was stirred using an ordinary rotary vane type stirrer The amount was measured, and the obtained results are also shown in Table 2. In all of Examples 1 and 2 and Comparative Examples 1, 2, 3, and 4, delamination of the vulcanized fiber laminated surface due to the dechlorination treatment did not occur.

[0020]

EFFECTS OF THE INVENTION Examples 1, 2 and Comparative Examples 1, 2, 3, 4,
As can be seen from Tables 1 and 2, a device in which dechlorinated zinc is fixed to a vibrating shaft that vibrates in the axial direction in one or more stages with non-rotatable vibrating vanes is used in the cleaning liquid in the dechlorinated zinc tank. By applying to the vibrating blade plate of such a device while vibrating at the frequency and the vibration width specified in the present invention,
Dezincification is greatly promoted, and in the same condition comparison, the chlorine content in the vulcanized fiber, that is, the zinc chloride content, compared to the case where such a device was not used or the cleaning solution was stirred with a normal rotary stirrer, About 1 / 1.5 to 1/15 without peeling phenomenon on the laminated surface
I was able to reduce it dramatically. By applying the dezincification method according to the present invention, the time required for the dezincification treatment, which has required a remarkably long time until now, is significantly shortened, and the effect of improving the productivity of vulcanized fiber can be enjoyed.

Claims (1)

[Claims] 1. A step of immersing one or more base papers in a concentrated aqueous solution of zinc chloride to swell, dissolve, and gelatinize the surface of the base papers, and when two or more base papers are used, those base papers. In the method for producing vulcanized fiber by sequentially applying the step of stacking, the step of dezincing the base paper with a cleaning solution, the step of drying the base paper, and the finishing step, a step for treating all or part of the dezincification of the base paper with the cleaning solution. Is a system in which a vibrating vane plate is fixed to a vibrating shaft vibrating in the axial direction in a non-rotatable manner in a single stage or in multiple stages, and the device is put into a cleaning solution in a dechlorination zinc tank.
A method for producing a vulcanized fiber, which is characterized in that it is performed while applying a vibration having a vibration width of 2 to 30 mm.