JPH06257012A - Production of polyester-based grid fiber - Google Patents

Abstract

PURPOSE:To obtain ultra-fine, high-strength grid fiber by subjecting a solution of a polyester-based polymer in methylene chloride to flash spinning under a specific condition. CONSTITUTION:A solution of a polyester-based polymer in methylene chloride is prepared by rise in temperature and blending under nitrogen pressure, is used as a spinning solution and spun from spinning holes having a pressure dropping chamber while pressurizing with nitrogen. Immediately after the spinning, methylene chloride of the solvent is instantly vaporized and a grid fiber structure is formed to give highly fibrillated grid fiber.

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 ultrafine and high strength polyester reticulated fiber.

[0002]

2. Description of the Related Art Conventionally, as a method for producing ultrafine fibers,
A method of melt spinning a multi-component filament in which a plurality of different polymers are arranged in a sea-island shape and removing a part of the polymer with a solvent, a method of extruding the molten polymer from a spinning hole and pulling it at high speed by a high temperature air flow The melt blown method is known. However, the former method using a multi-component filament requires various complicated steps to dissolve and remove the polymer, and the latter method can certainly obtain ultrafine fibers, but immediately after discharge. Since the polymer is pulled / thinned in the molten state, the stretch orientation and crystallization do not proceed sufficiently, and it is difficult to obtain a fiber having high strength.

On the other hand, as a method for producing ultrafine fibers, which is an alternative to the above-mentioned method, a solution obtained by dissolving a polymer in a specific solvent under high temperature and high pressure is further pressurized to above the autogenous pressure and spun into the air. The spinning method is known. For example,
U.S. Pat. No. 30,815,19 discloses a method in which a solution of a polymer and a low boiling point solvent is used as a spinning solution, the solution is spun through a spinning hole, and the solvent is instantaneously vaporized immediately after spinning to obtain ultrafine fibers. Has been done. However, by this method, although fibers of high strength are certainly obtained in the case of polyethylene polymers, fibers of extremely weak strength can be obtained in the case of polyester polymers. Regarding the flash spinning technique using this polyester polymer, Japanese Patent Application Laid-Open No. 62-104915 discloses a method for producing a polyester ultrafine fiber having high strength. That is, in the method described in the above publication, a solution containing a polyester polymer as a solute and a mixed solution of 1,1,2-trichloro-1,2,2-trifluoroethane and methylene chloride as a solvent is a spinning solution. The spinning solution is spun through a spinning hole at a high temperature around the melting point of the polyester polymer, and the solvent is instantaneously vaporized immediately after spinning to obtain ultrafine fibers. However, in this method, since the polymer is spun at a high temperature around the melting point of the polymer, thermal deterioration of the polymer is accelerated, it becomes difficult to obtain high-strength fiber, and the solvent is liable to be deteriorated in operation. There is a problem in that it causes a problem, or the use of the above-mentioned two kinds of organic solvents increases the number of solvent recovery steps, which is uneconomical.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems and to provide a method for stably producing ultrafine and high strength polyester reticulated fibers.

[0005]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems. That is, the present invention is to prepare a spinning solution by heating and kneading a solution containing a polyester polymer as a solute and methylene chloride as a solvent under nitrogen pressurization, and pressurizing the spinning solution with nitrogen to reduce the pressure. A method for producing a polyester reticulated fiber is characterized in that the solvent is instantaneously vaporized immediately after spinning through a spinning hole having a chamber to form a reticulated fiber structure.

Next, the present invention will be described in detail. The polyester polymer used in the present invention includes polyethylene terephthalate, polybutylene terephthalate, or acid components such as phthalic acid, isophthalic acid, glutaric acid, adipic acid, sulfoisophthalic acid, etc.
Diethylene glycol, propylene glycol, 1,4
A polyester copolymer obtained by copolymerizing a diol component such as butanediol, 2,2-bis (4-hydroxyateoxyphenyl) propane, bisphenol A, and polyalkylene glycol in an amount of up to 15 mol%. .
This polymer has a fiber-forming property and a relative viscosity of 1.3-0.5 when measured at a polymer concentration of 0.5% by weight and a temperature of 20 ° C. using an equal weight mixture of tetrachloroethane and phenol as a solvent. It is possible to use from 1.4 to those having a high relative viscosity of about 1.7, which are prepared by solid phase polymerization. However, the polymer has a relative viscosity of 1.3.
If the viscosity is less than 1, the degree of polymerization is too low to keep up with the spinning speed during flash spinning, and the spun fiber has a form of short fibers or substantially powder, which is preferable. Absent. In the present invention, the polymer or the spinning solution prepared by dissolving the polymer in a solvent,
Usually, a matting agent, a light-proofing agent, a heat-resistant agent, a pigment, a fiber-spreading agent, a UV absorber, a heat storage agent, a stabilizer and the like used for fibers may be added as long as the effects of the present invention are not impaired. it can.

In the present invention, a solution containing the polyester polymer as a solute and methylene chloride as a solvent is used as a spinning solution. In the present invention, taking into consideration the spinnability in flash-spinning using this spinning solution and the properties of the obtained fiber, these are the degree of polymerization of the polymer in this spinning solution, the autogenous pressure with respect to the temperature of the solvent, or the nitrogen content. It is difficult to unambiguously specify the concentration of the solute polyester-based polymer because it depends on the pressurization state and the like. It is preferable that the amount of methylene chloride as a solvent is 95% by weight or less and 70% by weight or more. If the concentration of this polymer is less than 5% by weight,
It becomes difficult to obtain fibers having a continuous structure of fibrils, while when the concentration of the polymer exceeds 30% by weight, the spun fibers have fibrils bonded to each other on their side faces and voids inside. It has a hollow structure of fibers,
High strength fibers cannot be obtained, which is not preferable. Therefore, in the present invention, the concentration of this polymer is set to 5% by weight or more and 30% by weight or less, preferably 10% by weight or more and 28% by weight or less, particularly preferably 15% by weight or more and 25% by weight or less.
It should be less than or equal to weight%. The methylene chloride used in the present invention has a boiling point of 40.2 ° C and a critical temperature of 237 ° C. In the present invention, since such methylene chloride is used as a solvent, it does not harm the global environment, which has been observed when conventional CFCs are used as a solvent.

In the present invention, the above polyester polymer is used as a solute, and methylene chloride is used as a solvent. These are filled in a dissolution apparatus and a solution is prepared by heating and kneading under nitrogen pressure, and the obtained solution is obtained. Is used as a spinning solution. As the melting device, an autoclave which has been used most widely in the past, or a continuous melting device including, for example, an extruder and a kneading device arranged continuously with the extruder can be used. In the present invention, it is preferable that the nitrogen which pressurizes the spinning solution in the dissolving device has a purity of 99% by weight or more and does not contain oxygen. Since nitrogen is an inert gas, it is hardly dissolved in the spinning solution and does not adversely affect the polymer, so that substantial pressure can be applied. On the other hand, carbon dioxide, which is the same inert gas, is easily dissolved in the spinning solution, and the pressure in the dissolution apparatus decreases as the dissolution progresses in the spinning solution, which is not preferable. When injecting and pressurizing this nitrogen into the dissolution apparatus, it is preferable to perform it at a low temperature of 60 ° C. or lower in order to prevent deterioration of the polyester polymer in the spinning solution. In the present invention, nitrogen, which is an inert gas, is allowed to exist in the dissolution apparatus from a low temperature state of 60 ° C. or lower to after the temperature is raised, so that the decomposition of the polymer in the spinning solution and the alteration of the solvent can be prevented. It is possible to prevent a decrease in the viscosity of the polymer during the step of preparing the solution by dissolving the polymer in the solution or during the flash spinning, and thus to improve the strength of the fiber. The pressure inside the melting device with nitrogen is at least 1 kg / c.
It is preferably m ² G, and particularly preferably 10 kg / cm ² G or more when it is desired to uniformly raise the temperature and dissolve the material in a short time.
The higher this pressure is, the higher the temperature rising property and the higher the solubility of the polymer, and the higher the substantial pressure of the spinning solution can be. Therefore, the stability of the flash spinning using this spinning solution is improved. be able to. However, this pressure is at most it is preferable to be ^{100kg / cm 2 G, 100kg /} cm 2 greater than G the shape of the fiber obtained by flushed spun using the spinning solution pressure 100kg
Although it is not so different from the case of less than / cm ² G or less, the fiber strength cannot be improved because the viscosity of the fiber is lowered, and heavy equipment for high pressure nitrogen is required, which is not preferable.

In the present invention, the dissolution time for dissolving the polymer in the solvent in the dissolution apparatus is 5 minutes or more and 60 minutes or more.
It is preferably not more than minutes. Polyester-based polymers are easily decomposed by heat, and especially when heated and mixed with methylene chloride used as a solvent, the dissolution time is not only the spinnability but also the fiber physical properties during the flash-spinning when the solution is used as the spinning solution. Especially, the fiber strength is greatly affected, and when the obtained fiber is used as a cloth, the strength, the elongation, or the abrasion resistance is affected. If the dissolution time exceeds 60 minutes, the thermal decomposition of the polymer in the spinning solution becomes severe and the strength of the fiber is not improved. On the other hand, if the dissolution time is less than 5 minutes, the dissolution of the polymer is insufficient. Therefore, it is difficult to obtain uniform fibers, or the filter is clogged during spinning, which is not preferable. Therefore, in the present invention, this dissolution time is set to 5 minutes or more and 60 minutes or less, preferably 7 minutes or more and 45 minutes or less, and particularly preferably 10 minutes or more and 3 minutes or less.
0 minutes or less.

In the present invention, the temperature at which the spinning solution is dissolved, that is, the melting temperature, and the temperature at which the spinning is performed, that is, the spinning temperature, are all such that the polymer is sufficiently dissolved in the solvent and the spinning solution is flash-spun to obtain an extremely fine particle. The temperature is not particularly limited as long as it is a temperature at which fibers having a structure in which the fibrils are aggregated and spread in a reticulated structure can be obtained, but if it is intentionally specified, the critical temperature of methylene chloride used as a solvent, 237 ° C, is taken into consideration. Over 170 ℃ 2
The temperature is preferably 40 ° C or lower. If the melting temperature or spinning temperature becomes higher than the critical temperature of the solvent used, the pressure will rise abnormally and the dissolution of the polymer will progress further, but at this time, the decomposition or alteration of the solvent itself will progress, and especially the spinning temperature will fluctuate Therefore, it is not preferable. Therefore, in the present invention, the melting temperature and the spinning temperature are set to 170 ° C or higher and 240 ° C or lower, preferably 180 ° C or higher and lower than the critical temperature of the solvent.

In the present invention, the pressure for flash-spinning the spinning solution is not particularly limited because it depends on the polymer concentration, the amount of solvent, the amount of nitrogen injected, etc., but is usually 40 kg / cm ² or more and 120 kg / cm ² or more. It is preferably not more than cm ² . If the spinning pressure is less than 40 kg / cm ² , the explosive force at the time of flash-spinning using a spinning solution is reduced, the orientation of the fibers is insufficient, the fiber strength is not improved, and the spinning state is unsatisfactory. It becomes difficult to stably obtain highly fibrillated fibers which are uniform, while when the pressure exceeds 120 kg / cm ² ,
The viscosity of the polymer in the spinning solution is lowered and the fiber strength is not improved, either of which is not preferable.

[0012]

In the present invention, a spinning solution is prepared by heating and kneading a solution containing a polyester polymer as a solute and methylene chloride as a solvent while heating and kneading under nitrogen pressure. By injecting nitrogen from the front and then flash-spinning the resulting spinning solution while pressurizing it with nitrogen, it is possible to obtain high-strength fibers having a structure in which extremely fine fibrils are aggregated and spread in a mesh. That is, in order to form such a fiber made of ultrafine fibrils, it is necessary to dissolve the polyester polymer as a solute sufficiently and uniformly in methylene chloride as a solvent. Since inert nitrogen is injected into the solvent and pressure is applied to the solvent before warming, the solubility can be improved. Since an inert gas is used, thermal degradation of the polymer and solvent can be prevented. It is possible to lower the melting temperature and the spinning temperature by improving the temperature, so that thermal deterioration of the polymer can be further prevented. By using a solution in which the polymer is dissolved at such a lower melting temperature than the conventional one and the polymer is uniformly dissolved in the solvent without being thermally deteriorated as a spinning solution, and moreover, in the case of flash spinning, a lower temperature than the conventional one is used. Good fibrillation and improvement in fiber strength are exhibited by spinning at the spinning temperature of temperature. Also,
In the present invention, the spinning solution is spun through a spinning hole having a pressure drop chamber while being pressurized with nitrogen, and the solvent is instantaneously vaporized immediately after spinning to form a reticulated fiber structure. By using it, the fiber strength can be further improved. That is, the strength of the fiber is expressed by sufficiently stretching / orienting the polymer molecular chain itself, and in the flash-spinning method, this stretching / orientation is accompanied by the instantaneous vaporization of the solvent immediately after spinning. Do by explosive force. The explosive force is the vaporizing force when the solvent is instantly vaporized, and usually means the force when the solvent vaporizes at once in 0.1 second or less. In the present invention, since the solvent methylene chloride is instantaneously vaporized and nitrogen is instantaneously released immediately after the flash spinning, the explosive force is further improved as compared with the conventional one, and thus the molecular chain of the polymer is sufficiently improved. The fiber is stretched and oriented, and the fiber strength is further improved.

[0013]

EXAMPLES Next, the present invention will be specifically described based on Examples. The measurement and evaluation of various characteristics in the examples were carried out by the following methods. Melting point of polymer: Differential scanning calorimeter D manufactured by Perkin Elmer
The melting point was defined as the temperature at which the exothermic value of the melting and absorption heat curve measured using the SC-2 type at a temperature rising rate of 20 ° C./min. Relative viscosity of polymer A: sample concentration of 0.5% by weight using an equal weight mixture of tetrachlorethane and phenol as a solvent
And it measured at the temperature of 20 degreeC. Fiber fineness (denier): The fineness was determined according to the method described in JIS L-1090. Tensile strength (g / denier) of fiber: Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd. was used, and 20 times / 5 cm of twist was added to each of 20 samples having a sample length of 10 cm, and a gripping interval was 5 cm and a tensile force was applied. The tensile strength was measured at a speed of 5 cm / min, and the average value of the obtained tensile strengths was converted to the fineness per unit weight to obtain the fiber strength (g / denier). Tensile elongation of fiber (%): Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd. was used to measure the above 20 samples at a tensile rate of 5 cm / min. The tensile elongation (%) of the fiber was used. Specific surface area (m ² / g) of fiber: The specific surface area (m ² / g) of the fiber was determined by the BET nitrogen adsorption method using a nitrogen adsorption device BELSORP28 type manufactured by Bell Japan. Fiber viscosity reduction rate (%): Using the relative viscosity A of the polymer and the relative viscosity B of the fiber obtained in the same manner, the following equation (1)
The viscosity reduction rate (%) of the fiber was calculated by. Fiber viscosity reduction rate (%) = (A−B) × 100 / A ···· (b)

Example 1 An autoclave was filled and closed with 50 g of a polyethylene terephthalate polymer having a melting point of 256 ° C. and a relative viscosity A of 1.6 and 200 cc of methylene chloride, and then the internal pressure of the autoclave was increased to 50 kg / cm ² G. After injecting until the temperature rises, the temperature rise is started while kneading at an appropriate speed. This solution has a polymer concentration of 20% by weight and methylene chloride of 8%.
It is 0% by weight. At this time, the internal temperature of the autoclave is 1
The temperature rising time from the temperature rise from 00 ° C to 220 ° C was 25 minutes. Then, this solution was kneaded at a temperature of 220 ° C. for 5 minutes to obtain a uniform solution. At this time, the internal pressure of the autoclave was 102 kg / cm ² G. Then, at this internal pressure, that is, the spinning pressure of 102 kg / cm ² G, the valve of the autoclave was immediately opened to bring the spinning solution into the atmosphere through a spinning hole having a pressure drop chamber of 0.7 mm and a hole length / hole diameter ratio of 1. By spinning, a reticulated fiber made of the polyethylene terephthalate polymer was obtained. At this time, the pressure in the pressure drop chamber was 93 kg / cm ² . Table 1 shows the production conditions and the properties of the obtained fiber. This reticulated fiber has a good fibrillation state, a small decrease in viscosity,
Moreover, the strength was high.

Example 2 An autoclave was filled with 30 g of a polyethylene terephthalate polymer having a melting point of 256 ° C. and a relative viscosity A of 1.7 and 200 cc of methylene chloride and then closed, and then the internal pressure of the autoclave was increased to 50 kg / cm ² G. After injecting until the temperature rises, the temperature rise is started while kneading at an appropriate speed. This solution has a polymer concentration of 13% by weight and methylene chloride of 8%.
It is 7% by weight. At this time, the internal temperature of the autoclave is 1
The temperature rising time from the temperature rise from 00 ° C to 220 ° C was 20 minutes. Then, this solution was kneaded at a temperature of 200 ° C. for 5 minutes to obtain a uniform solution. At this time, the internal pressure of the autoclave was 99 kg / cm ² G. Then, at this internal pressure, that is, the spinning pressure of 99 kg / cm ² G,
Thereafter, the spinning solution was spun into the atmosphere in the same manner as in Example 1 to obtain reticulated fibers made of the polyethylene terephthalate polymer. At this time, the pressure in the pressure drop chamber is 90 kg / cm
^{Was 2} . Table 1 shows the production conditions and the properties of the obtained fiber. The reticulated fiber was in a good fibrillated state, had little decrease in viscosity, and had high strength.

Examples 3 to 7 66.7 g of a polyethylene terephthalate polymer having a melting point of 256 ° C. and a relative viscosity A of 1.4 and 200 m of methylene chloride.
c was filled and closed in the autoclave, and then nitrogen was injected until the internal pressure of the autoclave increased to each pressure shown in Table 1, and then the temperature rising was started while kneading. This solution has a polymer concentration of 25% by weight and methylene chloride of 75% by weight. Then, this solution was added at 5
The mixture was kneaded for a minute to obtain a uniform solution. Subsequently, the spinning solution was spun into the atmosphere in the same manner as in Example 1 to obtain reticulated fibers made of the polyethylene terephthalate polymer. Table 1 shows the production conditions and the properties of the obtained fiber. Example 3-
All of the reticulated fibers obtained in Example 5 had a good fibrillation state, and because they were composed of extremely fine fibrils, they had a high specific surface area, a small decrease in viscosity, and a high strength. The reticulated fiber obtained in Example 6 was
Since the melting / spinning temperature was high, the viscosity of the fiber decreased significantly, and the strength was low reflecting this. The reticulated fiber obtained in Example 7 has a small number of fine fibrils because of its low melting / spinning temperature, but many fibrils are joined to each other on their side faces and form a hollow structure having cavities inside. The specific surface area was low and the strength was low.

Comparative Example 1 66.7 g of polyethylene terephthalate polymer having a melting point of 256 ° C. and a relative viscosity A of 1.4 and 200 m of methylene chloride.
c was charged into the autoclave and closed, and then the temperature was started while kneading without injecting nitrogen. This solution has a polymer concentration of 25% by weight and methylene chloride of 75% by weight. Then, this solution was added at 5
The mixture was kneaded for a minute to obtain a uniform solution.
The spinning solution was spun into the atmosphere in the same manner as in 1. to obtain reticulated fibers made of the polyethylene terephthalate polymer. Table 1 shows the production conditions and the properties of the obtained fiber. This reticulated fiber had a low viscosity because the polymer in the spinning solution had a reduced viscosity because nitrogen was not injected, and the strength of the reticulated fiber was extremely low, reflecting this.

[0018]

[Table 1]

Examples 8 to 10 The polymer concentration and solvent concentration were changed as shown in Table 2, the melting / spinning temperature was 210 ° C, and the melting time, that is, the internal temperature of the autoclave was increased from 100 ° C to 210 ° C. The spinning solution was spun into the atmosphere in the same manner as in Example 3 except that the temperature rising time until the temperature reached 30 minutes was 30 minutes to obtain reticulated fibers made of the polyethylene terephthalate polymer. Table 2 shows the production conditions and the properties of the obtained fiber. The reticulated fiber obtained in Example 9 had a good fibrillation state,
The viscosity was low and the strength was high. The reticulated fiber obtained in Example 8 had a good fibrillation state, was composed of extremely fine fibrils, had a small decrease in viscosity and high strength, but had a low concentration of polymer in the spinning solution. Therefore, the fibrils partially contained a portion that did not form a continuous fiber. On the other hand, the reticulated fiber obtained in Example 10 has a high strength, but since the polymer concentration of the spinning solution is high, some of the fibrils are joined to each other on their side surfaces and form a hollow structure having a cavity inside. The specific surface area was slightly low.

[0020]

[Table 2]

Examples 11 to 13 The melting / spinning temperature was 210 ° C., and the melting time, that is, the internal temperature of the autoclave increased from 100 ° C. to 210 ° C.
The spinning solution was spun into the atmosphere in the same manner as in Example 3 except that the temperature rising time until reaching the temperature was changed as shown in Table 3 to obtain reticulated fibers made of the polyethylene terephthalate polymer. Table 3 shows the production conditions and the properties of the obtained fiber. The reticulated fiber obtained in Example 11 has a good fibrillation state, has a high specific surface area because it is composed of ultrafine fibrils, and has a very low viscosity decrease of the fiber because the dissolution time of the polymer is short, Moreover, the strength was high. As shown in Examples 12 to 13, the obtained reticulated fibers tended to have a large decrease in the viscosity of the polymer due to the long dissolution time of the polymer, resulting in a decrease in the strength.

[0022]

[Table 3]

[0023]

Industrial Applicability The method for producing polyester reticulated fiber of the present invention is a spinning solution prepared by heating and kneading a solution containing a polyester polymer as a solute and methylene chloride as a solvent under nitrogen pressure, According to the present invention, the spinning solution is spun through a spinning hole having a pressure drop chamber while being pressurized with nitrogen, and the solvent is instantaneously vaporized immediately after spinning to form a reticulated fiber structure. , It is possible to stably manufacture ultrafine and high strength polyester reticulated fiber. The obtained reticulated fiber is highly fibrillated, has high strength, and is suitable as a material for a woven fabric, a knitted fabric, or a nonwoven fabric.

[Procedure amendment]

[Submission date] May 13, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Example 1 An autoclave was filled with 50 g of a polyethylene terephthalate polymer having a melting point of 256 ° C. and a relative viscosity A of 1.6 and 200 g of methylene chloride, and then the autoclave was filled with nitrogen so that the internal pressure of the autoclave was 50 kg / cm ² G. After injecting until the temperature rises, the temperature rise was started while kneading at an appropriate speed. This solution has a polymer concentration of 20% by weight and methylene chloride of 80%.
% By weight. At this time, the internal temperature of the autoclave is 10
The temperature rise time from 0 ℃ to 220 ℃ is 2
It was 5 minutes. Then, this solution is heated at 220 ° C. for 5
Kneading for minutes gave a uniform solution. At this time, the internal pressure of the autoclave was 102 kg / cm ² G. Then, at this internal pressure, that is, the spinning pressure of 102 kg / cm ² G, the valve of the autoclave was immediately opened to bring the spinning solution into the atmosphere through a spinning hole having a pressure drop chamber of 0.7 mm and a hole length / hole diameter ratio of 1. By spinning, a reticulated fiber made of the polyethylene terephthalate polymer was obtained. At this time, the pressure in the pressure drop chamber was 93 kg / cm ² . Table 1 shows the production conditions and the properties of the obtained fiber. This reticulated fiber has a good fibrillation state, a small decrease in viscosity,
Moreover, the strength was high.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Example 2 An autoclave was filled with 30 g of a polyethylene terephthalate polymer having a melting point of 256 ° C. and a relative viscosity A of 1.7 and 200 g of methylene chloride, and then the autoclave was filled with nitrogen so that the internal pressure of the autoclave was 50 kg / cm ² G. After injecting until the temperature rises, the temperature rise was started while kneading at an appropriate speed. This solution has a polymer concentration of 13% by weight and methylene chloride of 87%.
% By weight. At this time, the internal temperature of the autoclave is 10
The temperature rise time from 0 ℃ to 220 ℃ is 2
It was 0 minutes. Then, this solution was heated at a temperature of 200 ° C for 5
Kneading for minutes gave a uniform solution. At this time, the internal pressure of the autoclave was 99 kg / cm ² G. Continuing,
At this internal pressure, that is, the spinning pressure of 99 kg / cm ² G, the spinning solution was spun into the atmosphere in the same manner as in Example 1 to obtain reticulated fibers made of the polyethylene terephthalate polymer. At this time, the pressure in the pressure drop chamber was 90 kg / cm ² . Table 1 shows the production conditions and the properties of the obtained fiber.
This reticulated fiber has a good fibrillation state,
The viscosity was low and the strength was high.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Examples 3 to 7 66.7 g of a polyethylene terephthalate polymer having a melting point of 256 ° C. and a relative viscosity A of 1.4 and 200 g of methylene chloride.
Was filled and closed in the autoclave, and then nitrogen was injected until the internal pressure of the autoclave increased to each pressure shown in Table 1, and then the temperature rising was started while kneading. This solution is
The polymer concentration is 25% by weight and the methylene chloride is 75% by weight. Then, this solution was kneaded at each temperature shown in Table 1 for 5 minutes to obtain a uniform solution. Subsequently, the spinning solution was spun into the atmosphere in the same manner as in Example 1 to obtain reticulated fibers made of the polyethylene terephthalate polymer. Table 1 shows the production conditions and the properties of the obtained fiber. Each of the reticulated fibers obtained in Examples 3 to 5 has a good fibrillation state, and since it is composed of extremely fine fibrils, it has a high specific surface area, a small decrease in viscosity, and a high strength. there were. The reticulated fiber obtained in Example 6 had a high melting / spinning temperature and thus had a large decrease in fiber viscosity, and the strength was low reflecting this. The reticulated fiber obtained in Example 7 has a small number of fine fibrils because of its low melting / spinning temperature, but many fibrils are joined to each other on their side faces and form a hollow structure having cavities inside. The specific surface area was low and the strength was low.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Comparative Example 1 66.7 g of a polyethylene terephthalate polymer having a melting point of 256 ° C. and a relative viscosity A of 1.4 and 200 g of methylene chloride.
Was filled and closed in an autoclave, and then the temperature was started while kneading without injecting nitrogen. This solution is
The polymer concentration is 25% by weight and the methylene chloride is 75% by weight. Next, this solution was kneaded at each temperature shown in Table 1 for 5 minutes to obtain a uniform solution. Subsequently, a spinning solution was spun into the atmosphere in the same manner as in Example 1 and was composed of the polyethylene terephthalate polymer. A reticulated fiber was obtained. Table 1 shows the production conditions and the properties of the obtained fiber. This reticulated fiber
Since nitrogen was not injected, the viscosity of the polymer in the spinning solution decreased, and the fiber viscosity was low, reflecting this, and the strength was extremely low.

Claims (5)

[Claims] 1. A spinning solution prepared by heating and kneading a solution containing a polyester polymer as a solute and methylene chloride as a solvent under nitrogen pressurization. A method for producing a polyester-based reticulated fiber, which comprises spun through a spinning hole having the above, and instantaneously evaporates the solvent immediately after spinning to form a reticulated fiber structure. 2. The spinning solution contains 5 wt% to 30 wt% of a solute polyester polymer and 95 wt% to 70 wt% of a solvent methylene chloride. A method for producing the polyester-based reticulated fiber described. 3. The method for producing a polyester reticulated fiber according to claim 1, wherein the dissolution time of the solute in the solvent is 5 minutes or more and 60 minutes or less. 4. A melting temperature and a spinning temperature of 170 ° C. or higher 24
The method for producing the polyester network fiber according to claim 1, wherein the temperature is 0 ° C. or lower. 5. A spinning pressure of 40 kg / cm ² or more 1
20 kg / cm ² or less, The method for producing a polyester-based reticulated fiber according to claim 1, 2, 3 or 4.