JP2023144211A - Spun-dyed meta-type wholly aromatic polyamide fiber and method for producing the same - Google Patents

Abstract

To provide a spun-dyed meta-type wholly aromatic polyamide fiber colored in a bright, dark and deep color, which also possesses performance as a protective clothing.SOLUTION: An organic pigment is dispersed in an amide-based solvent at a pigment concentration of 10-50 mass% such that a particle diameter D90% is 2.0 μm or smaller, to obtain a pigment dispersion solution. After forming at least one type of an organic pigment dispersion solution, in which a viscosity η when a shear of 1 (1/s) is applied to the pigment dispersion solution is 7,000 mPa s or less, and the viscosity η when the shear of 1,000 (1/s) is applied to the pigment dispersion solution is 50 mPa s or less, the organic pigment dispersion solution is continuously mixed and agitated with a solution obtained by dissolving a meta-type wholly aromatic polyamide in an amide-based solvent, to produce a spinning dope. Then, the same is spun such that the organic pigment is contained in the fiber at a total of 2.0-10.0 mass% based on the total mass of the fiber.SELECTED DRAWING: None

Description

The present invention relates to a colored spun-dyed meta-type wholly aromatic polyamide fiber, and more particularly to a sprue-dyed meta-type wholly aromatic polyamide fiber colored in a vivid, dark and deep color, and a method for producing the same. It is something.

It is well known that fully aromatic polyamide fibers produced from aromatic diamines and aromatic dicarboxylic acid dihalides have excellent heat resistance and flame retardancy. Meta-type wholly aromatic polyamide fibers represented by amide are known to be particularly useful as heat-resistant and flame-retardant fibers. Taking advantage of these characteristics, meta-type wholly aromatic polyamide fibers are suitably used, for example, in the field of protective clothing such as firefighting suits and heat-resistant work clothes (see Patent Document 1).

For use in the clothing field, it is common to use colored fibers, and especially for protective clothing that is often used outdoors, the lightness L of the fiber is 40 or less, so that stains are less noticeable. Dark-colored designs have become mainstream. Known methods for obtaining such darkly colored fibers include a post-dyeing method in which fibers are made and then dyed using dyes, and a dope dyeing method in which pigments are added to spinning dope and then made into fibers. .

However, meta-type wholly aromatic polyamide fibers that are colored by post-dying using dyes after fiberization have the disadvantage of causing discoloration or fading when exposed to light, and also due to the dyes coming off during washing. It also has the disadvantage of causing discoloration and fading.

Therefore, for protective clothing such as firefighting suits and heat-resistant work clothes that are used outdoors for long periods of time, coloring is carried out using a dope dyeing method in which a pigment is added to a spinning dope and then turned into fibers. However, it is generally known that when pigments whose particles are larger than dyes are added to fibers, the strength decreases. In particular, when adding a large amount to make a dark color, the problem is how to suppress the decrease in fiber strength.

A similar problem occurs in the coloring of para-aramid fibers, which are known to be high-strength fibers. For example, when coloring para-aramid fibers, adding a black inorganic pigment to the fiber at a pigment concentration of 2.0% by mass results in a satisfactory result. Although fibers with a certain density can be obtained, there is a problem in that the strength decreases.

Therefore, by adding at least one kind of red, yellow, and blue organic pigments in a balance of 1 to 6% by mass based on the fiber mass, and a black inorganic pigment in a balance of 1% by mass or less, the lightness L value can be maintained while maintaining the strength. 30.2 to 33.5 has been proposed, and a method for coloring para-aramid fibers that is colored black has been proposed, and by using a black inorganic pigment in combination with an organic pigment, a black color with a lower lightness L value while maintaining strength has been proposed. Para-aramid fibers have been obtained (see Patent Document 2).

However, this method was aimed at coloring para-aramid fibers black, and did not provide a sufficient solution to obtain meta-type wholly aromatic polyamide fibers that were colored in bright and deep colors. .

On the other hand, heat-resistant pigments that do not discolor even when exposed to air at 400°C for 15 seconds are added to the fibers in an amount of 0.1% by mass to 15% by mass so that the average particle size is 0.4μm or less. Fully aromatic polyamide fibers have been proposed, and it is possible to make them darker by increasing the amount of pigment added, but in the dry spinning method used in this method, In the spun fibrous polymer solution, the solvent evaporates and dries from near the surface of the formed fibrous material, resulting in a dense and strong skin layer on the fiber surface. Therefore, the strength can be maintained even if the amount of pigment added is increased, but it is difficult to sufficiently remove the solvent remaining in the fibrous material after spinning even if the solvent is washed with water or the like. Therefore, when the fibers obtained by this method are used in a high temperature atmosphere due to the solvent remaining in the fibers, yellowing may occur, and organic gas may be generated due to volatilization or decomposition of the remaining solvent. There was a problem.

On the other hand, in this method, in addition to the dry spinning method, a spinning dope in which a pigment is added to a polymer dissolved in a water-soluble organic solvent is introduced into an aqueous coagulation bath or an aqueous coagulation bath containing a high concentration of inorganic salts. A wet spinning method has also been proposed. In this method, the solvent does not volatilize during the spinning step, but when introduced into an aqueous coagulation bath or an aqueous coagulation bath containing a high concentration of inorganic salts, the solvent evaporates from near the surface of the fibrous polymer solution. At the same time as water is desorbed into the coagulation bath, water infiltrates from near the surface of the coagulated fibrous material to form a strong skin layer. For this reason, like fibers produced by dry spinning, strength can be maintained even if the amount of pigment added is increased, but problems such as yellowing and organic gas due to the solvent remaining in the fibers cannot be avoided (Patent Document 3). reference).

Furthermore, due to increasing environmental awareness, in the fiber manufacturing process, we have adjusted the components or conditions of the coagulation bath so that the coagulation form does not have a skin core, and we have made spruce-dyed meta-type fully aromatic polyamide fibers that are plastically stretched at a specific ratio. A manufacturing method has been proposed (see Patent Document 4). However, with this manufacturing method, there is no skin layer that contributes to strength, so there is a problem that strength decreases especially when a large amount of pigment is contained. I couldn't get what I wanted.

Japanese Patent Application Publication No. 2006-016709 KR20160011865A Japanese Patent Application Publication No. 1-139814 Patent No. 5852127

The purpose of the present invention is to solve the problems in the prior art, and to create a process-dyed meta-type wholly aromatic polyamide fiber that has a low amount of residual solvent, is colored in a vivid, dark, and deep color, and also has the performance as protective clothing. The object of the present invention is to provide a manufacturing method thereof.

As a result of intensive studies to solve the above problems, the inventors found that when a fiber contains a predetermined amount of an organic pigment having a specific particle size distribution, and more preferably a small amount of a black inorganic pigment, The inventors have discovered that the above object can be achieved and have arrived at the present invention.

That is, according to the present invention,
1. A spun-dyed meta-type wholly aromatic polyamide fiber in which the amount of residual solvent is 0.1% by mass or less based on the total fiber mass, and the fiber contains at least one type of organic pigment in a total amount of 2.0 to 10.0% by mass. % by mass, and the fiber has a lightness L of 40 or less and a tensile strength of 3.5 cN/dtex or more,
2. The spun-dyed meta-type wholly aromatic polyamide fiber according to 1 above, wherein the black inorganic pigment is contained in an amount of 0.1 to 0.5% by mass based on the total fiber mass;
3. An organic pigment is dispersed in an amide solvent at a pigment concentration of 10 to 50% by mass so that the particle size D90% measured by the following method is 2.0 μm or less, and a pigment dispersion solution is prepared. An organic material having a viscosity η of 7,000 mPa·s or less when sheared at 1 (1/s), and a viscosity η of 50 mPa·s or less when the pigment dispersion solution is subjected to 1,000 (1/s) shear. After creating at least one type of pigment dispersion solution, the organic pigment dispersion solution is continuously mixed and stirred with a solution of meta-type wholly aromatic polyamide dissolved in an amide solvent to create a spinning dope, and then the organic The production of the spun-dyed meta-type wholly aromatic polyamide fiber according to claim 1, wherein the fiber is spun so that the pigment is contained in the fiber in a total amount of 2.0 to 10.0% by mass based on the total fiber mass. Method,
<Measurement method of particle size D90%>
The particle size of the particles was measured according to JIS Z 8825, the frequency (%) was calculated, and the particle size D90% with a cumulative frequency of 90% was obtained. Specifically, Microtrac MT3000 from Microtrac Bell Co., Ltd. was used, laser wavelength: 780 nm, measurement time: 30 sec, number of measurements: 2, transparency: reflection, solvent: ion exchange water, solvent refractive index: 1. Measured by laser diffraction/scattering method at .33,
is provided.

According to the present invention, it is possible to obtain a spun-dyed meta-type wholly aromatic polyamide fiber that has a low amount of residual solvent, is colored in a vivid, dark, and deep color, and also has the performance as protective clothing. It is possible to finish clothing with a design that has a bright color, rather than a dark and dull black color, even though it is a dark color that makes it difficult to see dirt.

The present invention will be explained in detail below.
The meta-type fully aromatic polyamide in the present invention is a polyamide produced by, for example, solution polymerization or interfacial polymerization using a meta-type aromatic diamine and a meta-type aromatic dicarboxylic acid halide as raw materials. For example, it may be copolymerized with other copolymerization components such as para-type, within a range that does not inhibit.

The above-mentioned meta-type aromatic diamines include meta-phenylene diamine, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenylsulfone, etc., and substituents such as halogens and alkyl groups having 1 to 3 carbon atoms on their aromatic rings. For example, 2,4-tolylenediamine, 2,6-tolylenediamine, 2,4-diaminochlorobenzene, 2,6-diaminochlorobenzene, etc. can be used. Among these, meta-phenylene diamine or the above-mentioned mixed diamine containing 70 mol% or more of meta-phenylene diamine is preferred.

In addition, the meta-aromatic dicarboxylic acid halides include isophthalic acid halides such as isophthalic acid chloride and isophthalic acid bromide, and derivatives thereof having a substituent such as a halogen or an alkoxy group having 1 to 3 carbon atoms on the aromatic ring; For example, 3-chloroisophthalic acid chloride and 3-methoxyisophthalic acid chloride can be used. Among these, the above-mentioned mixed carboxylic acid halides containing isophthalic acid chloride or isophthalic acid chloride in an amount of 70 mol % or more are preferred.

Copolymerization components that can be used in addition to the diamines and dicarboxylic acid halides mentioned above include aromatic diamines such as paraphenylene diamine, 2,5-diaminochlorobenzene, 2,5-diaminobrobenzene, and benzene derivatives such as aminoanisidine. , 1,5-naphthylene diamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ketone, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenylmethane, etc.; Examples of dicarboxylic acid halides include terephthalic acid chloride, 1,4-naphthalenedicarboxylic acid chloride, 2,6-naphthalenedicarboxylic acid chloride, 4,4'-biphenyldicarboxylic acid chloride, 4,4'-diphenyl etherdicarboxylic acid chloride, etc. .

The copolymerization ratio of these copolymerization components is preferably 20 mol % or less based on the total acid components of the polyamide, since the properties of the meta-type wholly aromatic polyamide tend to deteriorate if the copolymerization ratio becomes too large. Particularly suitable meta-type wholly aromatic polyamides are polyamides in which 80 mol % or more of all repeating units are metaphenylene isophthalamide units, and among them, polymetaphenylene isophthalamide is preferred.
The degree of polymerization of such a meta-type wholly aromatic polyamide is suitably such that the intrinsic viscosity (IV) measured at 30° C. using 97% by mass concentrated sulfuric acid as a solvent is in the range of 1.3 to 3.0.

Next, a spinning dope is prepared by dissolving the meta-type fully aromatic polyamide obtained here in a dissolving solvent, but it is also possible to use the meta-type fully aromatic polyamide as it is as a spinning dope without isolating it after polymerization. . An amide solvent can generally be used as the solvent used here, and the main amide solvents include N-methyl-2-pyrrolidone (hereinafter sometimes referred to as NMP) and dimethylformamide (hereinafter referred to as DMF). (hereinafter sometimes referred to as DMAc), dimethylacetamide (hereinafter sometimes referred to as DMAc), and the like. Among these, NMP or DMAc is preferably used from the viewpoint of solubility and handling safety.

The solution concentration may be appropriately selected from the viewpoint of the coagulation rate in the next spinning/coagulation step and the solubility of the polymer. For example, when the polymer is polymetaphenylene isophthalamide and the solvent is NMP. In this case, it is usually preferably within the range of 10 to 30% by mass.

In the present invention, an organic pigment is added to the spinning dope in an amount of 2.0 to 10.0% by mass based on the mass of the polymer in order to obtain spun-dyed fibers colored in the vivid and deep colors demanded by the market. do. The higher the addition concentration, the smaller the lightness L value and the darker and brighter the hue. Therefore, addition is preferably from 2.3 to 9.5% by mass, and more preferably from 6.0 to 9.0% by mass. .

When the amount of the organic pigment added is less than 2.0% by mass, the brightness is higher than the target brightness and does not have sufficient density. On the other hand, if the amount of organic pigment added exceeds 10.0% by mass, the physical properties of the fiber will be significantly reduced, resulting in physical properties insufficient for use in protective clothing.

Further, at this time, in order to obtain a deep color while suppressing the total amount of pigment added, it is preferable to add a black inorganic pigment in an amount of 0.1 to 0.5% by mass based on the polymer component. However, when more than 0.5% by mass of the black inorganic pigment is added, the lightness L value decreases, and although a deep color can be obtained, the color is not vivid but dark and dull. This is undesirable because it will not be possible to provide fibers with the bright, dark colors required by the market.

In the present invention, since the fibers are colored in a dark color, a large number of pigment particles are present inside the fibers, which generally reduces the fiber strength. Therefore, in advance, the organic pigment required for addition is dispersed in the amide solvent used in the polymer solution at a pigment concentration of 10 to 50% by mass so that the particle size D90% is 2.0 μm or less. It is necessary to perform spinning while continuously mixing and stirring the pigment dispersion solution with a solution of a meta-type wholly aromatic polyamide dissolved in an amide solvent to prepare a spinning dope. Here, in order to add the pigment so as not to reduce the fiber strength, it is necessary to add the pigment sufficiently dispersed in the amide solvent so that the pigment concentration is 10 to 50% by mass. At this time, if moisture is mixed in, the spinnability will deteriorate, so weigh out an amide solvent with a moisture content of 100 ppm or less in a container that can be stirred at high speed under a dry nitrogen atmosphere, cool it to 0°C, and then pour it into the container. While stirring at high speed, the organic pigment is added little by little and dispersed so that the particle size D90% is 2.0 μm or less. If the dispersion is insufficient, such as when the particle size D90% is larger than 2.0 μm, the fiber strength decreases significantly, resulting in insufficient strength for use in protective clothing.

Note that the particle size D90% refers to a particle size at which the cumulative frequency is 90% of the total by integrating the frequencies starting from the smallest particle size.
The pigment dispersion solution prepared here is prepared by creating a dispersion solution of at least one type of pigment and the required number of pigments to obtain the target color, adjusting it to match the target density and color of the raw cotton obtained, and meta-type. The mixture is continuously mixed and stirred with a solution in which a wholly aromatic polyamide is dissolved in an amide solvent.

In addition, in order to obtain dark-colored fibers, a large amount of the pigment dispersion solution is fed through piping in order to continuously mix the pigment dispersion solution with a solution of meta-type wholly aromatic polyamide dissolved in an amide solvent. However, if the distance from the tank is long, pressure loss in the piping may make it impossible to send the liquid. Therefore, the viscosity η when a shear of 1 (1/s) is applied to the pigment dispersion solution used here is 7000 mPa・s or less, and when a shear of 1000 (1/s) is applied to the pigment dispersion solution, It is necessary that the viscosity η is 50 mPa·s or less.

If the viscosity η when the shear applied to the pigment dispersion solution is 1 (1/s) exceeds 7000 mPa・s, the pressure loss in the piping will increase due to the high viscosity, making it difficult to pump the pigment dispersion solution. Cheap. On the other hand, if the viscosity η when the shear applied to the solution is 1000 (1/s) exceeds 50 mPa・s, the pressure loss will similarly increase, causing problems such as the inability to stably feed the pigment dispersion solution. come.

In addition, in the present invention, when colored inorganic pigments other than black inorganic pigments, such as ultramarine, red iron oxide, titanium oxide, iron oxide, etc., are used in order to give a vivid and deep color, they may be dispersed in a solvent in advance. If the amount added is too large, the fiber strength will decrease, which is not desirable.
The organic pigments used here include, but are not limited to, azo-based, phthalocyanine-based, perinone-based, perylene-based, and anthraquinone-based pigments.

Next, the spinning dope prepared by being continuously mixed with the pigment dispersion solution as described above is spun into a coagulating liquid and coagulated. The spinning device is not particularly limited, and conventionally known wet spinning devices can be used. Further, as long as stable wet spinning can be performed, there is no need to particularly limit the number of spinning holes, arrangement state, hole shape, etc. of the spinneret. For example, the number of holes is 500 to 30,000, and the diameter of the spinning holes is 0.05. A multi-hole spinneret for yarns of ~0.2 mm may also be used. Further, the temperature of the spinning dope during spinning from the spinneret is suitably in the range of 10 to 90°C.

As an example of the coagulation bath used to obtain the fibers of the present invention, an aqueous solution of an amide solvent containing no inorganic salt with a concentration of 45 to 60% by mass is used at a bath liquid temperature in the range of 10 to 35°C. If the concentration of the amide solvent is less than 45% by mass, the skin will have a thick structure, the cleaning efficiency in the cleaning process will decrease, and the solvent will remain in the final fiber. Additionally, if the concentration of the amide solvent exceeds 60% by mass, it will not be possible to coagulate uniformly all the way to the inside of the fiber, resulting in many problems such as single filament breakage during fiber molding. do. It should be noted that the immersion time of the fibers in the coagulation bath is suitably in the range of 0.1 to 30 seconds.

Next, while the fibers obtained by coagulation in a coagulation bath are in a plastic state, the fibers are stretched in a plastic drawing bath. The plastic stretching bath liquid is not particularly limited, and conventionally known bath liquids can be employed.

In order to obtain the fibers of the present invention, the stretching ratio in the plastic drawing bath must be in the range of 3.5 to 5.0 times, more preferably in the range of 3.7 to 4.5 times. . In the production of the fibers of the present invention, removal of the solvent from the coagulated yarn can be promoted by plastically drawing the fibers within a specific range of magnification in a plastic drawing bath.

When the stretching ratio in the plastic stretching bath is less than 3.5 times, solvent removal from the coagulated thread becomes insufficient. Moreover, the breaking strength becomes insufficient, making it difficult to handle in processing steps such as spinning steps. On the other hand, if the stretching ratio exceeds 5.0 times, single yarn breakage occurs, resulting in poor process stability.
The temperature of the plastic stretching bath is preferably in the range of 10 to 90°C. Preferably, when the temperature is in the range of 20 to 90°C, process stability is good.

Next, the solvent remaining in the fibers is washed away. In this step, the fibers drawn in the plastic drawing bath are thoroughly washed. Since washing affects the quality of the fibers obtained, it is preferable to perform the washing in multiple stages. In particular, the temperature of the washing bath in the washing process and the concentration of the amide solvent in the washing bath liquid affect the state of extraction of the amide solvent from the fibers and the state of infiltration of water from the washing bath into the fibers. Therefore, for the purpose of optimizing these conditions, it is preferable to conduct the washing step in multiple stages and to control the temperature conditions and the concentration conditions of the amide solvent.

The temperature conditions for washing and the concentration conditions of the amide solvent are not particularly limited as long as they can satisfy the quality of the fibers finally obtained. However, if the initial cleaning bath is heated to a high temperature of 60° C. or higher, water will immediately penetrate into the fibers, creating huge voids in the fibers and causing quality deterioration. For this reason, the initial cleaning bath is preferably kept at a low temperature of 30° C. or lower.

If a solvent remains in the fiber, it not only reduces the flame retardance of the fiber, but also improves the environmental safety in processing products using the fiber and using products formed using the fiber. do not have. Therefore, the amount of residual solvent contained in the fiber used in the present invention needs to be 0.1% by mass or less, and preferably 0.08% by mass or less.

Next, in the dry heat treatment step, the fibers that have undergone the washing step are dried and heat treated. The dry heat treatment method is not particularly limited, but examples include methods using a heated roller, hot plate, etc. By passing through the dry heat treatment, the meta-type wholly aromatic polyamide fiber used in the present invention can finally be obtained.

In order to obtain the meta-type wholly aromatic polyamide fiber of the present invention, which is colored in a bright, dark and deep color and has the performance as protective clothing, a dry heat treatment at 100°C was carried out for drying. Afterwards, it is necessary to repeat the dry heat treatment at least twice in the range of 280 to 310°C for 5 seconds or less each time, and it is more preferable to carry out the dry heat treatment in the range of 290 to 300°C. If the heat treatment temperature is less than 280°C, the crystallization of the fibers will be insufficient and the shrinkability of the fibers will increase. On the other hand, if the temperature exceeds 310℃ or if the treatment is carried out for more than 5 seconds at a time, the yellow fluorescent pigment absorbs too much thermal energy, causing a structural change instead of remaining in the excited state, resulting in a change in hue. A problem arises. The dry heat treatment carried out in the range of 280 to 310°C contributes to improving the breaking strength of the resulting fibers.

The meta-type wholly aromatic polyamide fiber that has been subjected to the dry heat treatment may be further crimped if necessary. Furthermore, after the crimping process, the fibers may be cut into appropriate fiber lengths and provided to the next process. In some cases, it may also be wound up as a multifilament yarn.

The thus obtained meta-type wholly aromatic polyamide fiber of the present invention contains at least one type of organic pigment in a total of 2.0 to 10.0% by mass, and has a lightness L of 40 or less and a tensile strength. It is important that the strength is 3.5 cN/dtex or higher. If the lightness L of the fiber exceeds 40, it is impossible to dye it with a bright, dark and deep color.On the other hand, if the tensile strength is less than 3.5 cN/dtex, the strength is too low and the protective The performance as clothing cannot be demonstrated.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited to the following Examples and Comparative Examples.
In addition, "parts" and "%" in the examples are all values based on mass unless otherwise specified, and quantitative ratios indicate mass ratios unless otherwise specified. Each physical property value in Examples and Comparative Examples was measured by the following method.

<Intrinsic viscosity (I.V.)>
The polymer was dissolved in 97% concentrated sulfuric acid and measured at 30°C using an Ostwald viscometer.

<Fineness>
Based on JIS L1015, measurements were carried out in accordance with method A of positive fineness, and the results were expressed in terms of apparent fineness.

<Particle size D90%>
The particle size of the particles was measured according to JIS Z 8825, the frequency (%) was calculated, and the particle size D90% with a cumulative frequency of 90% was obtained. Specifically, Microtrac MT3000 from Microtrac Bell Co., Ltd. was used, laser wavelength: 780 nm, measurement time: 30 sec, number of measurements: 2, transparency: reflection, solvent: ion exchange water, solvent refractive index: 1. It was measured using a laser diffraction/scattering method at .33.

<Tensile strength, tensile elongation>
Based on JIS L1015, the values of tensile strength at break and tensile elongation measured under the following conditions using Instron Model No. 5565 were taken as the tensile strength and tensile elongation of the fiber.
(Measurement condition)
Grasp interval: 20mm
Initial load: 0.044cN (1/20g)/dtex
Tensile speed: 20mm/min

<Lightness L value>
The obtained raw cotton was thoroughly opened using a card machine, 1.3 grams were taken out, packed into a circular measurement cell with a diameter of 30 mm, and measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo).
(Measurement condition)
Color system: Hunter Specular reflection method: SCI
Light source: D65

<Color judgment>
The obtained raw cotton was visually confirmed under a standard light source D65, and the color depth and vividness were determined.

[Example 1]
Into a reaction vessel under a dry nitrogen atmosphere, 721.5 parts by mass of N,N-dimethylacetamide (DMAc) with a moisture content of 100 ppm or less was weighed, and in this DMAc, 97.2 parts by mass (50.18 mol) of metaphenylenediamine was added. %) was dissolved and cooled to 0°C. To this cooled DMAc solution, 181.3 parts by mass (49.82 mol %) of isophthalic acid chloride (hereinafter abbreviated as IPC) was gradually added with stirring to perform a polymerization reaction.

Next, 66.6 parts by mass of calcium hydroxide powder having an average particle size of 10 μm or less was weighed out and slowly added to the polymer solution in which the polymerization reaction had been completed to carry out a neutralization reaction. After the addition of calcium hydroxide was completed, stirring was continued for an additional 40 minutes to obtain a transparent polymer dope.
When polymetaphenylene isophthalamide was isolated from the obtained polymer dope and its IV was measured, it was found to be 1.65. Further, the polymer concentration in the polymer dope was 17% by mass.

84% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. The organic pigment Pigment Orange 61 was gradually added to this DMAc while stirring at high speed to give a concentration of 16% by mass, and the mixture was further stirred at high speed for 1 hour to create a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc. Stored in pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.82 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 6890.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 47.3 mPa.・It was s.

Since the target density of the obtained raw cotton is a bright color with a lightness L value of 38 to 40, the above pigment dispersion solution is added to the above polymer dope without mixing with a polymer in advance. After sequentially mixing and stirring via dope piping so that the pigment amount = 6.00% by mass, it was continuously discharged from a spinneret with a pore diameter of 0.07 mm and a number of holes of 500 into a coagulation bath with a bath temperature of 30 ° C. It was spun. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.

After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.
The obtained raw cotton had fineness of 1.67 dtex, breaking strength of 3.54 cN/dtex, and breaking elongation of 38.2%, which had physical properties that were acceptable for use in protective clothing.

In addition, since the amount of residual solvent in the raw cotton was 0.03% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Industries), and the result was that the L value was 39.5, which was the target value. It was confirmed that the brightness was achieved. Further, as a result of visually checking the color under standard light source D65, it was confirmed that the color was deep and vivid.

[Comparative example 1]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

85% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. The organic pigment Pigment Orange 73 was gradually added to this DMAc while stirring at high speed to give a concentration of 15% by mass, and the mixture was further stirred at high speed for 1 hour to create a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc. Stored in pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.93 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 7500.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 69.0 mPa.・It was s.

Since the target density of the obtained raw cotton is a bright color with a lightness L value of 38 to 40, the above pigment dispersion solution is added to the above polymer dope without mixing with a polymer in advance. It is necessary to mix and stir sequentially through the dope piping so that the amount of pigment is 6.00% by mass, but the shear viscosity of the pigment dispersion solution is high and the pressure loss in the liquid delivery piping is large, making it difficult to mix the pigment. could not. For this reason, it was not possible to obtain the desired raw cotton using this manufacturing method.

[Comparative example 2]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

87% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. While stirring at high speed, organic pigment Pigment Red 254 was gradually added to this DMAc at a concentration of 13% by mass, and the mixture was further stirred at high speed for 1 hour to create a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc. Stored in pigment tank. Here, when the particle size of the pigment dispersion solution was measured, it was found that D90%=1.84 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity is 5820.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 24.6 mPa.・It was s.

85.3% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. While stirring at high speed, an inorganic orange pigment Pigment Orange 82 was gradually added to this DMAc at a concentration of 14.7% by mass, and the mixture was further stirred at high speed for 1 hour to form a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc. It was prepared and stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.63 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 21.2 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 24.3 mPa.・It was s.

Since the target density of the raw cotton obtained is a bright color with a lightness L value of 38 to 40, the pigment dispersion solution is added to the polymer dope without mixing with the polymer etc. in advance. Two pigment dispersion solutions were successively mixed and stirred via a dope pipe so that Red was 0.70% by mass and Pigment Orange 82 was 6.00% by mass. The material was spun by being discharged from a spinneret into a coagulation bath at a bath temperature of 30°C. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

Since the amount of residual solvent in the obtained raw cotton was 0.03% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo), and the L value was 39.3, which was the target value. It was confirmed that the brightness of Further, as a result of visually checking the color under standard light source D65, it was confirmed that the color was deep and vivid.
However, the physical properties of the raw cotton are such that the fineness is 1.67 dtex, the breaking strength is 2.54 cN/dtex, and the breaking elongation is 15.3%, and because it contains a large amount of inorganic pigment, it cannot obtain sufficient strength for protective clothing. There wasn't.

[Comparative example 3]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

84% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. The organic pigment Pigment Orange 61 was gradually added to this DMAc while stirring at high speed to give a concentration of 16% by mass, and the mixture was further stirred at high speed for 1 hour to create a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc. Stored in pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=2.81 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 6080.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 44.8 mPa.・It was s.

Since the target density of the obtained raw cotton is a bright color with a lightness L value of 38 to 40, the above pigment dispersion solution is added to the above polymer dope without mixing with a polymer in advance. After sequentially mixing and stirring via dope piping so that the pigment amount = 6.00% by mass, it was continuously discharged from a spinneret with a pore diameter of 0.07 mm and a number of holes of 500 into a coagulation bath with a bath temperature of 30 ° C. It was spun. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

The obtained raw cotton had a fineness of 1.67 dtex, a breaking strength of 3.42 cN/dtex, and a breaking elongation of 36.6%, which meant that it could not provide sufficient strength for protective clothing.
In addition, since the amount of residual solvent in the raw cotton was 0.03% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo), and the result was that the L value was 40.1, which was the target value. It was confirmed that the brightness had not been reached. Further, as a result of visually checking the color under the standard light source D65, it was confirmed that the color was not sufficiently deep.

[Example 2]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

86% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. While stirring at high speed, the organic pigment Pigment Blue 15:1 was gradually added to this DMAc at a concentration of 14% by mass, and the mixture was further stirred at high speed for 1 hour to create a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc. and stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.42 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 12.4 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 13.2 mPa.・It was s.

Since the target density of the raw cotton obtained is a bright color with a lightness L value of 38 to 40, the pigment dispersion solution is added to the polymer dope without mixing with the polymer etc. in advance. After sequentially mixing and stirring Blue 15:1 to a concentration of 2.00% by mass through a dope pipe, it was continuously poured into a coagulation bath at a bath temperature of 30°C from a spinneret with a pore diameter of 0.07 mm and a number of holes of 500. It was discharged and spun. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

The fineness of the obtained raw cotton was 1.67 dtex, the breaking strength was 3.69 cN/dtex, and the breaking elongation was 36.3%.
Since the amount of residual solvent in the obtained raw cotton was 0.02% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo), and the L value was 39.8, which was the target value. It was confirmed that the brightness of Further, as a result of visually checking the color under standard light source D65, it was confirmed that the color was deep and vivid.

[Comparative example 4]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

In addition, a pigment dispersion solution was prepared by dispersing Pigment Blue 15:1 to 14% by mass in N,N-dimethylacetamide (DMAc) in the same manner as in Example 2, and stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.42 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 12.4 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 13.2 mPa.・It was s.

The target density of the raw cotton obtained is a bright color with a lightness L value of 38 to 40, but the pigment dispersion solution is added to the polymer dope without mixing it with the polymer in advance. After sequentially mixing and stirring Blue 15:1 to a concentration of 1.90% by mass through a dope pipe, it was continuously poured into a coagulation bath at a bath temperature of 30°C from a spinneret with a pore diameter of 0.07 mm and a number of holes of 500. It was discharged and spun. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

The fineness of the obtained raw cotton was 1.67 dtex, the breaking strength was 3.67 cN/dtex, and the breaking elongation was 38.9%.
Since the amount of residual solvent in the obtained raw cotton was 0.02% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo), and the L value was 40.7, which was the target value. It was confirmed that the brightness had not been reached. Further, as a result of visually checking the color under the standard light source D65, it was confirmed that the color was not sufficiently deep.

[Example 3]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

In addition, a pigment dispersion solution was prepared by dispersing Pigment Blue 15:1 to 14% by mass in N,N-dimethylacetamide (DMAc) in the same manner as in Example 2, and stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.42 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 12.4 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 13.2 mPa.・It was s.

Next, a pigment dispersion solution was prepared by dispersing Pigment Red 254 in N,N-dimethylacetamide (DMAc) to a concentration of 13% by mass in the same manner as in Comparative Example 2, and the solution was stored in a pigment tank. Here, when the particle size of the pigment dispersion solution was measured, it was found that D90%=1.84 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity is 5820.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 24.6 mPa.・It was s.

Further, 83% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. While stirring at high speed, an organic pigment Pigment Yellow 138 was gradually added to this DMAc at a concentration of 17% by mass, and the mixture was further stirred at high speed for 1 hour to create a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc. Stored in pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.98 μm. In addition, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 6230.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 38.4 mPa.・It was s.

Since the target density of the raw cotton obtained is a bright color with a lightness L value of 30 to 32, the pigment dispersion solution is added to the polymer dope without mixing it with the polymer in advance. After sequentially mixing and stirring three pigment dispersion solutions through a dope pipe so that Blue 15:1 was 0.56% by mass, Pigment Red 254 was 1.98% by mass, and Pigment Yellow 138 was 7.46% by mass. The material was continuously spun by being discharged from a spinneret with a hole diameter of 0.07 mm and a number of holes of 500 into a coagulation bath at a bath temperature of 30°C. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

Since the amount of residual solvent in the obtained raw cotton was 0.03% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo), and the L value was 31.8, which was the target value. It was confirmed that the brightness of Further, as a result of visually checking the color under standard light source D65, it was confirmed that the color was deep and vivid.
In addition, the physical properties of the raw cotton were sufficient for use in protective clothing, with a fineness of 2.21 dtex, breaking strength of 3.51 cN/dtex, and breaking elongation of 37.2%.

[Comparative example 5]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

In addition, a pigment dispersion solution was prepared by dispersing Pigment Blue 15:1 to 14% by mass in N,N-dimethylacetamide (DMAc) in the same manner as in Example 2, and stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.42 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 12.4 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 13.2 mPa.・It was s.

Next, a pigment dispersion solution was prepared by dispersing Pigment Red 254 in N,N-dimethylacetamide (DMAc) to a concentration of 13% by mass in the same manner as in Comparative Example 2, and the solution was stored in a pigment tank. Here, when the particle size of the pigment dispersion solution was measured, it was found that D90%=1.84 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity is 5820.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 24.6 mPa.・It was s.

Furthermore, a pigment dispersion solution was prepared by dispersing Pigment Yellow 138 in N,N-dimethylacetamide (DMAc) to a concentration of 17% by mass in the same manner as in Comparative Example 2, and the solution was stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.98 μm. In addition, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 6230.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 38.4 mPa.・It was s.

Since the target density of the raw cotton obtained is a bright color with a lightness L value of 30 to 32, the pigment dispersion solution is added to the polymer dope without mixing it with the polymer in advance. After sequentially mixing and stirring three pigment dispersion solutions through a dope pipe so that Blue 15:1 was 0.62% by mass, Pigment Red 254 was 2.18% by mass, and Pigment Yellow 138 was 8.20% by mass. The material was continuously spun by being discharged from a spinneret with a hole diameter of 0.07 mm and a number of holes of 500 into a coagulation bath at a bath temperature of 30°C. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

Since the amount of residual solvent in the obtained raw cotton was 0.03% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo), and the L value was 30.2, which was the target value. It was confirmed that the brightness of Further, as a result of visually checking the color under standard light source D65, it was confirmed that the color was very deep and vivid.
However, the physical properties of the raw cotton were such that the fineness was 2.23 dtex, the breaking strength was 2.21 cN/dtex, and the breaking elongation was 12.4%, which were insufficient for use in protective clothing.

[Comparative example 6]
Polymerization and neutralization were performed in the same manner as in Example 1 to obtain a transparent polymer dope. This dope was placed in water with high speed stirring and coagulated, then filtered, washed with water, and dried to isolate the polymer.
This polymer was dissolved in N-methyl-2-pyrrolidone (NMP) at a concentration of 17% by mass to prepare a polymer solution. IV was 1.65.

In addition, N-methyl-2-pyrrolidone (NMP) was used as the solvent in the same manner as in Comparative Example 2, and a pigment dispersion solution in which Pigment Blue 15:1 was dispersed at 14% by mass was prepared. It was prepared and stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.83 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 12.3 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 12.8 mPa.・It was s.

Next, using N-methyl-2-pyrrolidone (NMP) as a solvent in the same manner as in Comparative Example 2, a pigment dispersion solution was created by dispersing Pigment Red 254 in this solvent to a concentration of 13% by mass. and stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.89 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 4200.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 22.0 mPa.・It was s.

Furthermore, using N-methyl-2-pyrrolidone (NMP) as a solvent in the same manner as in Comparative Example 2, a pigment dispersion solution was prepared in which Pigment Yellow 138 was dispersed at 17% by mass. , stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.45 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 5200.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 25.0 mPa.・It was s.

Since the target density of the raw cotton obtained is a bright color with a lightness L value of 30 to 32, the pigment dispersion solution is added to the polymer dope without mixing it with the polymer in advance. After sequentially mixing and stirring three pigment dispersion solutions through a dope pipe so that Blue 15:1 was 0.62% by mass, Pigment Red 254 was 2.18% by mass, and Pigment Yellow 138 was 8.20% by mass. The mixture was heated to 80° C. and continuously spun into a coagulation bath with a bath temperature of 80° C. from a spinneret with a hole diameter of 0.07 mm and a number of holes of 500. The coagulation liquid had a composition of water/CaCl2=60/40 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 2.7 times in a plastic stretching bath having a composition of water/NMP=45/55 at a temperature of 80°C.
After stretching, it was washed in a 20°C water/NMP=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C warm water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

The lightness L value of the obtained raw cotton was measured using a spectrophotometer SD7000 (manufactured by Nippon Denshoku Kogyo), and as a result, it was confirmed that the target lightness was achieved, with L value = 30.1. Further, as a result of visually checking the color under standard light source D65, it was confirmed that the color was very deep and vivid.
Furthermore, the physical properties of the raw cotton are such that the fineness is 2.19 dtex, the breaking strength is 5.73 cN/dtex, and the breaking elongation is 42.3%, which means that a skin layer is formed on the fiber surface due to the coagulation conditions, even when the pigment content is high. We were able to obtain sufficient physical properties for use in protective clothing.
However, the skin layer formed on the fiber surface made it difficult to remove the residual solvent inside, and the amount of residual solvent in the obtained raw cotton was as high as 1.98% by mass.

[Example 4]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

88% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. Three types of pigments were added to this DMAc while stirring at high speed: 4.78% by mass of organic pigments Pigment Blue 15:1, 5.51% by mass of Pigment Red 254, and 1.71% by mass of Pigment Yellow 138. After the gradual addition, high speed stirring was further performed for 1 hour to prepare a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc, and the solution was stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.78 μm. In addition, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 4300.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 38.3 mPa.・It was s.

85.0% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. A black inorganic pigment, Pigment Black 7, was gradually added to this DMAc while stirring at high speed to give a concentration of 15.0% by mass, and the mixture was further stirred at high speed for 1 hour to obtain a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc. It was prepared and stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=0.72 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 9.4 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 9.8 mPa.・It was s.

Since the target density of the obtained raw cotton is a bright color with a lightness L value of 30 to 32, the above pigment dispersion solution is added to the above polymer dope without mixing with a polymer etc. in advance. The two pigment dispersion solutions prepared above were successively mixed and stirred via the dope pipe so that the total amount of pigment was 2.46% by mass and the black inorganic pigment Pigment Black 7 was 0.50% by mass. The material was spun by being discharged from a spinneret with a diameter of 0.07 mm and 500 holes into a coagulation bath at a bath temperature of 30°C. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

The physical properties of the raw cotton obtained were that the fineness was 1.42 dtex, the breaking strength was 3.56 cN/dtex, and the breaking elongation was 36.2%, which were sufficient for use in protective clothing.
In addition, since the amount of residual solvent in the obtained raw cotton was 0.01% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo), and the L value was 30.4. It was confirmed that the target brightness was achieved. Further, as a result of visually checking the color under standard light source D65, it was confirmed that the color was very deep and vivid.

[Example 5]
A polymer solution was prepared in the same manner as in Example 1. IV was 1.65, and the polymer concentration in the polymer dope was 17% by mass.

88% by mass of N,N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less was weighed into a container capable of high-speed stirring under a dry nitrogen atmosphere, and cooled to 0°C. Three types of pigments were added to this DMAc while stirring at high speed: 4.24% by mass of organic pigments Pigment Blue 15:1, 6.88% by mass of Pigment Red 254, and 0.88% by mass of Pigment Yellow 138. After the gradual addition, high speed stirring was further performed for 1 hour to prepare a pigment dispersion solution in which the pigment was uniformly dispersed in DMAc, and the solution was stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=1.74 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 4500.0 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 40.2 mPa.・It was s.

Next, a pigment dispersion solution was prepared by dispersing Pigment Black 7 in N,N-dimethylacetamide (DMAc) to a concentration of 15% by mass in the same manner as in Comparative Example 2, and the solution was stored in a pigment tank. When the particle size of the pigment dispersion solution was measured, it was found that D90%=0.72 μm. Further, as a result of measuring the shear concentration of the pigment dispersion solution, when the shear is 1 (1/s), the shear viscosity η = 9.4 mPa・s, and when the shear is 1000 (1/s), the shear viscosity is 9.8 mPa.・It was s.

Since the target density of the obtained raw cotton is a bright color with a lightness L value of 30 to 32, the above pigment dispersion solution is added to the above polymer dope without mixing with a polymer etc. in advance. The two pigment dispersion solutions prepared above were successively mixed and stirred via the dope pipe so that the total amount of pigment was 1.50% by mass and the black inorganic pigment Pigment Black 7 was 1.0% by mass, and then the pore size was continuously adjusted. The material was spun by being discharged from a spinneret with a diameter of 0.07 mm and 500 holes into a coagulation bath at a bath temperature of 30°C. The coagulation liquid had a composition of water/DMAc=45/55 (mass%), and was discharged into a coagulation bath at a yarn speed of 7 m/min to perform spinning of the first color.

Subsequently, stretching was performed at a stretching ratio of 3.7 times in a plastic stretching bath having a composition of water/DMAc=45/55 at a temperature of 40°C.
After stretching, it was washed in a 20°C water/DMAc=70/30 bath (immersion length 1.8 m), then in a 20°C water bath (immersion length 3.6 m), and then in a 60°C hot water bath (immersion length 5 .4 m) for thorough cleaning.
After washing, the fibers are subjected to dry heat treatment using a heated roller with a surface temperature of 300°C, and then the fibers are bundled and passed through a crimper to give crimps, and then cut with a cutter to obtain short fibers of 51 mm. A dyed raw cotton colored with a pigment was obtained.

The physical properties of the raw cotton obtained were that the fineness was 1.43 dtex, the breaking strength was 3.52 cN/dtex, and the breaking elongation was 34.2%, which were sufficient for use in protective clothing.
In addition, since the amount of residual solvent in the obtained raw cotton was 0.01% by mass, the lightness L value was measured using a spectrocolorimeter SD7000 (manufactured by Nippon Denshoku Kogyo), and the L value was 30.1. It was confirmed that the target brightness was achieved. However, when the color was visually checked under the standard light source D65, it was found that although the color was very deep, it lacked vividness and was blackish and dull, and the target color could not be achieved.
Table 1 shows the physical properties of the spun-dyed meta-type wholly aromatic polyamide fibers obtained in Examples 1 to 5 and Comparative Examples 1 to 6.

The present invention provides a sprue-dyed meta-type fully aromatic polyamide fiber used for protective clothing, etc., which is colored in a vivid, dark, and deep color and also has performance as protective clothing. It is something to do.

Claims (3)

A spun-dyed meta-type wholly aromatic polyamide fiber in which the amount of residual solvent is 0.1% by mass or less based on the total fiber mass, and the fiber contains at least one type of organic pigment in a total amount of 2.0 to 10.0% by mass. % by mass, and the fiber has a lightness L of 40 or less and a tensile strength of 3.5 cN/dtex or more. The spun-dyed meta-type wholly aromatic polyamide fiber according to claim 1, wherein the black inorganic pigment is contained in an amount of 0.1 to 0.5% by mass based on the total fiber mass. An organic pigment is dispersed in an amide solvent at a pigment concentration of 10 to 50% by mass so that the particle size D90% measured by the following method is 2.0 μm or less, and a pigment dispersion solution is prepared. An organic material having a viscosity η of 7,000 mPa·s or less when sheared at 1 (1/s), and a viscosity η of 50 mPa·s or less when the pigment dispersion solution is subjected to 1,000 (1/s) shear. After creating at least one type of pigment dispersion solution, the organic pigment dispersion solution is continuously mixed and stirred with a solution of meta-type wholly aromatic polyamide dissolved in an amide solvent to create a spinning dope, and then the organic The production of the spun-dyed meta-type wholly aromatic polyamide fiber according to claim 1, wherein the fiber is spun so that the pigment is contained in the fiber in a total amount of 2.0 to 10.0% by mass based on the total fiber mass. Method.
<Measurement method of particle size D90%>
The particle size of the particles was measured according to JIS Z 8825, the frequency (%) was calculated, and the particle size D90% with a cumulative frequency of 90% was obtained. Specifically, Microtrac MT3000 from Microtrac Bell Co., Ltd. was used, laser wavelength: 780 nm, measurement time: 30 sec, number of measurements: 2, transparency: reflection, solvent: ion exchange water, solvent refractive index: 1. It was measured using a laser diffraction/scattering method at .33.