JP2010156083A - Protective garment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protective garment having a specific color, and excellent in mechanical properties such as wash resistance or strength. <P>SOLUTION: The protective garment is produced by: adding iron oxide (III) fine particle slurry dispersed in an amide-based solvent and having a specific average particle diameter to a para-type fully aromatic copolyamide polymer solution to be mixed so as to prepare a polymer solution (master butch) highly containing the fine particles; mixing the polymer solution (master butch) containing the fine particles with a polymer solution containing no particles to prepare a polymer solution; using the polymer solution to produce fiber; and using a regular amount of the thus obtained fiber to make a protective garment having the specific color, free from partial discoloration, and excellent in mechanical properties such as wash resistance and strength. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a protective garment in which discoloration due to washing or the like is suppressed, color unevenness is small, and mechanical properties such as tear strength are excellent.

Conventionally, aramid fibers mainly composed of aromatic dicarboxylic acid components and aromatic diamine components, especially para-type aramid fibers, have various characteristics such as strength, high elastic modulus, and high heat resistance. It is widely used for protective clothing such as fire-fighting clothes, bulletproof and blade-proof materials.
In recent years, in the field of protective clothing such as fire fighting clothing, in addition to the physical properties of the fiber itself such as mechanical properties and flame retardancy, design properties having various color variations are also an important factor. In order to color the fiber other than the original color of the fiber, a method of dyeing the fiber, a method of coloring the raw material at the stage of yarn production, and the like can be mentioned.

  In the case of polyparaphenylene terephthalamide (hereinafter referred to as “PPTA”) fiber, which is known as a typical para-type wholly aromatic polyamide fiber, yarns are mainly produced using a liquid crystalline polymer dope, and therefore an inorganic pigment is added. The liquid crystal properties, spinnability, and mechanical properties are hindered. For this reason, it is difficult to apply inorganic pigments, and it is common to color fibers mainly by dyeing.

  Various studies have been made so far regarding the dyeing of such PPTA fibers. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2007-16343) has a buckling portion (kink band) and this seat. There have been reports on fiber structures containing para-type wholly aromatic polyamide fibers whose bent portions are dyed with a cationic or disperse dye. However, since PPTA fiber is generally difficult to dye due to its high chemical resistance, it cannot be sufficiently dyed without color unevenness unless a larger number of buckling parts that are preferentially dyed are physically added. And when many buckling parts are provided, the defect of a fiber will increase and the problem that mechanical properties, such as intensity | strength, are impaired significantly will arise. In general, the fiber colored by dyeing has a problem of fading easily due to, for example, washing because the physical binding force between the fiber and the dye is weak.

On the other hand, para-type wholly aromatic copolyamide fibers produced by using an isotropic polymer dope have no significant effect on the spinnability, crystal structure, and mechanical properties even when inorganic pigments are added to the polymer dope. . For this reason, the fibers are colored mainly by coloring the raw material (hereinafter referred to as “original”).
Various studies have been made so far regarding such an original yarn. For example, in Patent Document 2 (Japanese Patent Laid-Open No. 2005-232642), a specific hue is obtained by adding titanium oxide fine particles or the like. Para-type wholly aromatic polyamide fibers provided are reported. It is possible to obtain para-type wholly aromatic polyamide fibers having a specific hue by the method as described in this publication, and since the pigment is contained in the polymer by original attachment, color fading is suppressed by washing etc. However, it was still not satisfactory with respect to variations in hue and color unevenness.
Accordingly, there has been a great demand for protective clothing that satisfies the high demands for color unevenness while suppressing discoloration such as washing and having excellent mechanical properties.
JP 2007-016343 A JP-A-2005-232642

  The present invention has been made against the background of the prior art, and an object thereof is to provide a protective garment having a specific hue and excellent mechanical properties such as durability and strength for washing.

  In order to achieve the object, the present inventor first expressed the sedimentation velocity of a general powder in a solvent, and paid attention to the Stokes equation shown as Equation 1.

  As shown in this equation, the sedimentation rate of the powder is proportional to the specific gravity difference between the powder and the solvent and inversely proportional to the viscosity of the solvent. When producing para-type wholly aromatic copolyamide fibers containing fine particles, a slurry is prepared by dispersing fine particles in an amide solvent that is a good solvent for the para-type wholly aromatic copolyamide polymer. A method of mixing with a para-type wholly aromatic copolyamide polymer solution dissolved in a system solvent is common. However, since the specific gravity of amide solvents is often around 1, and the viscosity is low, for example, in a slurry in which fine particles with a high specific gravity such as iron oxide are dispersed, the surface of the fine particles is temporarily surface-treated. Even if the affinity was increased, the particles easily settled and it was difficult to stably store the slurry. In addition, even if sufficient dispersibility of the slurry during storage can be achieved by sufficient stirring or the like, it easily settles during transportation until it is mixed with the para-type wholly aromatic copolyamide polymer solution. Therefore, the dispersion of the fine particles in the para-type wholly aromatic copolyamide polymer solution becomes non-uniform, and as a result, the fine particles are segregated in the fiber. For this reason, a significant reduction in mechanical properties cannot be avoided, and in the case where the fine particles are fine particles intended for original deposition such as pigments, there has been a problem that significant color unevenness occurs in the fibers. . Therefore, when a protective garment is produced using such a fiber, color unevenness is clearly seen, which is not preferable from the viewpoint of design.

  Therefore, the present inventor has intensively studied in order to more efficiently achieve high dispersibility of the fine particles in the polymer solution and the resulting fiber. As a result, first, a fine particle slurry having a specific average particle size dispersed in an amide solvent is added to and mixed with a para-type wholly aromatic copolyamide polymer solution, whereby a polymer containing fine particles in a high concentration is obtained. If a polymer solution is prepared by preparing a solution (masterbatch) and then mixing a polymer solution containing the fine particles (masterbatch) and a polymer solution containing no fine particles, even if iron oxide (III) having a high specific gravity is prepared. It has been found that even if it is a fine particle, the segregation of the fine particle in the polymer solution being stored can be suppressed. Further, if the fiber is produced using the polymer solution, the segregation of the fine particle in the fiber can be suppressed. Para-type wholly aromatic copoly, with fine particles dispersed efficiently and uniformly without impairing physical properties An amide fiber was obtained, and a protective garment was made using a certain amount of the resulting fiber, resulting in less color fading due to washing, less color unevenness, and mechanical properties such as tear strength. The inventors have found that excellent protective clothing can be obtained and have reached the present invention.

Thus, in the present invention, the constituent fiber contains at least an iron (III) oxide particle having an average particle diameter (D50) of 0.05 μm to 2 μm, and the L ^* value a ^* value of the color system representing the hue thereof. b ^* mean respectively ^{L *} values of 40 to 65, an ^{a *} value of +. 20 to + 30, ^{b *} value + 12 + 18, and the standard deviation of the hue, each ^{L *} value of 1.0 or less A para-type wholly aromatic copolyamide fiber having an a ^* value of 0.5 or less and a b ^* value of 0.3 or less and a tensile strength of 18 cN / dtex or more and less than 25 cN / dtex, It is a protective garment having a ratio of 40% by mass or more with respect to the total mass, characterized in that the washing durability evaluated in accordance with JIS L0844 A-2 is a grade 4 or more color change by gray scale judgment. Related to protective clothing.

  The protective clothing of the present invention has a specific hue, has no color unevenness, and is a protective clothing with excellent mechanical properties such as washing durability and strength. It is very useful in the field of protective clothing such as fire-fighting clothing that requires physical properties.

Hereinafter, embodiments of the present invention will be described in detail.
<Protective clothing>
The protective clothing in the present invention refers to what is obtained by sewing a fabric made of fibers, and does not particularly limit the structure, the number of laminated layers, the basis weight, the presence or absence of surface treatment such as water repellent treatment, and the tear strength is If 90 N or more can be achieved, it can be appropriately applied according to the use and purpose of the protective clothing to be produced. Note that. The fabric here refers to a woven fabric, a knitted fabric or a non-woven fabric using the above-mentioned fibers, and uses a spun yarn or a non-woven fabric obtained by blending each staple fiber obtained by crimping each fiber and then cutting. It is preferable. The crimping process conditions, cut length, blending method, spun yarn count, woven structure, knitted structure, nonwoven fabric processing conditions, etc. are not particularly limited, and can be appropriately selected according to the application and purpose. . Also, a plurality of different spun yarn counts, woven structures, knitted structures, and non-woven fabrics may be combined depending on the application and purpose.

(Fibers that make up protective clothing)
As the fibers used in the present invention, para-type wholly aromatic copolyamide fibers, which are organic fibers generally used in protective clothing applications such as fireproof clothing, para-type wholly aromatic polyamide fibers, meta-type wholly aromatic polyamide fibers, Examples thereof include polybenzazole fibers, wholly aromatic polyester fibers and the like. Specific examples thereof include para-type wholly aromatic copolyamide fibers such as copolyparaphenylene-3,4'oxydiphenylene-terephthalamide, and polyparaphenylene. Para-type wholly aromatic polyamide fibers such as terephthalamide, meta-type wholly aromatic polyamide fibers such as polymetaphenylene isophthalamide, polybenzazole fibers such as polyparaphenylenebenzobisoxazole and polyparaphenylenebenzobisthiazole, and polyarylate Name all aromatic polyester fibers such as Can do.

  In the present invention, one kind or two or more kinds of these fibers can be used. From the viewpoint of mechanical properties and washing durability of the obtained protective clothing, at least a para type wholly aromatic copolyamide fiber is used. The ratio is 40 mass% or more with respect to the total mass. Other fiber types, ratios and combinations thereof are not particularly limited, but para-type wholly aromatic polyamide fibers such as polyparaphenylene terephthalamide and meta-type wholly aromatic polyamides such as polymetaphenylene isophthalamide. Fiber is preferred.

<Para-type wholly aromatic copolyamide>
Here, the para-type wholly aromatic copolyamide in the present invention is a polymer in which two or more kinds of divalent aromatic groups are directly linked by an amide bond, and is generally an amide polar solvent according to a known method. Among them, it can be obtained by polycondensation reaction of aromatic dicarboxylic acid dichloride and aromatic diamine. In this case, the aromatic group may be one in which two aromatic rings are bonded with oxygen, sulfur, or an alkyl group. In addition, these divalent aromatic rings may be unsubstituted or substituted with a lower alkyl group such as a methyl group or a methyl group, or a halogen group such as a methoxy group or a chlorine group. The type and the number of substituents are not particularly limited.

[Method for producing para-type wholly aromatic copolyamide]
The para-type wholly aromatic copolyamide used in the present invention can be obtained by a polycondensation reaction of an aromatic dicarboxylic acid dichloride and an aromatic diamine in an amide solvent according to a generally known method.

(Aromatic dicarboxylic acid dichloride)
Examples of the aromatic dicarboxylic acid dichloride in the present invention include terephthalic acid dichloride, 2-chloroterephthalic acid dichloride, 3-methylterephthalic acid dichloride, 4,4′-biphenyldicarboxylic acid dichloride, 2,6-naphthalenedicarboxylic acid dichloride, and isophthalic acid. Acid dichloride and the like, and one or two or more of these aromatic dicarboxylic acid dichlorides can be used, and the kind and composition ratio are not particularly limited, and the mechanical properties of the fiber and the polymer obtained after polymerization It can be appropriately adjusted in consideration of the handling properties of the dope.

(Aromatic diamine)
Examples of the aromatic diamine in the present invention include paraphenylene diamine, 3,4'-diaminodiphenyl ether, parabiphenylene diamine, 5-amino-2- (4-aminophenylene) benzimidazole, 1,4-dichloroparaphenylene diamine, and the like. However, it is not limited to these, and the aromatic ring may have a substituent or other heterocyclic ring. In the present invention, two or more of these are used. The combination and composition ratio are not particularly limited, and can be appropriately adjusted in consideration of the mechanical properties of the fiber and the handling property of the polymer dope obtained after polymerization. The combination is most preferably a combination of paraphenylenediamine and 3,4'-diaminodiphenyl ether from the viewpoints of versatility and mechanical properties of fibers, and the composition ratio is not particularly limited. 30 to 70 mol% and 70 to 30 mol% are preferred, respectively, more preferably 40 to 60 mol% and 60 to 40 mol%, most preferably 45 to 55 mol% and 55 to 55 mol%, respectively, with respect to the amount of the group diamine. 45 mol%.

(Amide solvent)
In obtaining the wholly aromatic copolyamide fiber used as the material for the protective clothing of the present invention, examples of the amide solvent used for polymerization and spinning of the wholly aromatic copolyamide used as the raw material include N-methyl-2-pyrrolidone. (Hereinafter referred to as “NMP”), N, N-dimethylformamide, N, N-dimethylacetamide, dimethylimidazolidinone, and the like, solubility in para-type wholly aromatic copolyamide polymer, versatility, harmfulness, It can select suitably from viewpoints, such as handleability.

(Colored)
The above para-type wholly aromatic copolyamide fiber is appropriately colored from the viewpoint of the design of the protective clothing obtained. Each of the above-mentioned fibers has a different original color, and therefore, coloring is performed by coloring a raw material by adding a pigment (hereinafter referred to as “original coating”) or dyeing the obtained fiber at the stage of spinning. From the viewpoints of the production process and physical properties of each fiber, the method of dressing and dyeing can be appropriately selected. For example, in the case of copolyparaphenylene-3,4'oxydiphenylene-terephthalamide fiber, which is a para-type wholly aromatic copolyamide, a method of adding a pigment in the yarn making stage and making the yarn is preferable. At that time, it is necessary to sufficiently disperse the color unevenness and the like and to disperse the pigment uniformly in the fiber without segregation.

(Iron (III) oxide fine particles)
In particular, in the case of the iron (III) oxide fine particles used in the present invention, since the specific gravity is large and sedimentation or the like occurs in the spinning stage, causing segregation, for example, a pigment such as iron (III) oxide is previously added to the polymer solution. A fully aromatic copolyamide fiber with reduced color unevenness, for example, copolyparaphenylene Although 3,4'oxydiphenylene-terephthalamide fiber can be obtained, it is not particularly limited to this method. About dyeing, although the optimal dyeing conditions differ with each fiber, it can color by a well-known dyeing method using a well-known dye.

  The pigment added to the para-type wholly aromatic copolyamide fiber in the present invention is most preferably iron (III) oxide fine particles from the viewpoint of the hue and versatility of the resulting fiber. The shape of the iron (III) oxide fine particles, the presence or absence of surface treatment, and the like are not particularly limited, but the average particle size (D50) is 0.05 μm to 2 μm. When the average particle diameter (D50) is less than 0.05 μm, it is difficult not only to prepare such iron (III) fine particles per se, but also to uniformly disperse the polymer dope up to this size. When stirring is required for a long time and / or a high shearing force, and it is difficult to prepare an efficient polymer solution, productivity is not preferable. On the other hand, when the average particle diameter (D50) exceeds 2 μm, depending on the fiber diameter of the obtained fiber, when the average particle diameter is 5 to 20 μm, the size of the fine particles with respect to the fiber diameter increases. Since the continuous layer of the polymer in the fiber is inhibited by the fine particles, the portion where the fine particles are present becomes a defect, and the mechanical properties of the fiber are remarkably impaired.

The content of iron oxide (III) fine particles in the para-type wholly aromatic copolyamide fibers, the color system representing the color of the para-type wholly aromatic copolyamide fibers L ^* value a ^* value b ^* value each L ^* value Is 40 to 65, a ^* value is +20 to +30, b ^* value is +12 to +18, and the standard deviation of the hue is L ^* value is 1.0 or less, a ^* value is 0.5 or less, b ^{* Although the} value is not particularly limited as long as it can achieve 0.3 or less, from the viewpoint of the hue and mechanical properties of the fiber, 0.1 to 0.1 mass relative to the para-type wholly aromatic copolyamide fiber mass. It is preferable that it is 10 mass%. When the content of iron (III) oxide fine particles in the para-type wholly aromatic copolyamide fiber is less than 0.1% by mass, the original hue of the fiber becomes dominant, and a fiber having a target hue can be obtained. It is not preferable due to difficulty. On the other hand, when it exceeds 10% by mass, even if the dispersion of iron (III) fine particles in the fiber is uniform, the amount of the polymer itself that contributes to the strength in the fiber is reduced, so that 18 cN / dtex or more It is not preferable because it is difficult to achieve the tensile strength. For example, in the case of copolyparaphenylene 3,4'-oxydiphenylene terephthalamide fiber, which is a kind of para-type wholly aromatic copolyamide fiber, even if the fiber does not contain iron (III) oxide fine particles, 25 cN / Achieving strengths above dtex is difficult and is a manufacturing limit. Therefore, the tensile strength of the para-type wholly aromatic copolyamide fiber in the present invention is 18 cN / dtex or more and less than 25 cN / dtex.

The L ^* value a ^* value b ^* value of the color system representing the hue of the fiber referred to here is measured using a known color difference meter (device name: CR-400, manufactured by Konica Minolta Co., Ltd.). It is an index that represents the hue of the fiber that can be.
The average particle size (D50) referred to here is measured using a laser diffraction type particle size distribution measuring device (device name: SALD-200VER, manufactured by Shimadzu Corporation) by dispersing fine particles in water. D50 is the particle size of the fine particles, and D50 refers to the 50th particle size counted from the smallest particle size when measuring the particle size of 100 samples, for example, and the average particle size of the measurement sample Means.

(Polycondensation reaction)
The polycondensation reaction between the aromatic diamine and the aromatic dicarboxylic acid dichloride can be performed by a known method, for example, by heating the system and using a known stirrer. The reaction conditions can be adjusted as appropriate while monitoring the progress of the polymerization.
The calcium chloride generated by the neutralization reaction can be used as it is as a solubilizing agent that enhances the dissolution of the produced polymer in the solvent, and therefore does not need to be removed from the system.

  The para-type wholly aromatic copolyamide polymer obtained by polycondensation is an isotropic polymer solution (dope) dissolved in an amide solvent such as NMP. The obtained polymer solution (dope) can be used as it is in the spinning process without isolating the polymer. However, the concentration of the para-type wholly aromatic copolyamide polymer at this time significantly affects the viscosity and stability of the polymer dope, and greatly affects the spinnability and the like in the subsequent spinning process. For this reason, it is preferable that a polymer concentration is 2-10 mass%. In adjusting the polymer concentration and viscosity, an appropriate amount of an amide solvent such as N-methyl-2-pyrrolidone can be added.

  The intrinsic viscosity of the para-type wholly aromatic copolyamide (value measured at 30 ° C. for a solution having a polymer concentration of 0.5 g / dl in 98% concentration of sulfuric acid) is usually about 2.5 to 5. . The intrinsic viscosity as used herein is a known viscosity obtained by dissolving an isolated para-type wholly aromatic copolyamide polymer in a solvent soluble therein, such as sulfuric acid, and using this polymer solution, for example, using an Ostwald viscometer. It refers to the inherent viscosity of the polymer calculated by the measurement method.

<Para type wholly aromatic copolyamide fiber>
[Method for producing para-type wholly aromatic copolyamide fiber]
In obtaining the para-type wholly aromatic copolyamide fiber of the present invention, first, a fine particle slurry having a specific average particle diameter dispersed in an amide solvent is added to the para-type wholly aromatic copolyamide polymer solution. A polymer solution (masterbatch) containing fine particles at a high concentration is prepared by mixing, and then a polymer solution containing the fine particles (masterbatch) and a polymer solution not containing the fine particles are mixed to prepare a polymer solution. And fibers are produced using the polymer solution.

(Create master batch)
In preparing the master batch, the obtained para-type wholly aromatic copolyamide polymer dope and iron (III) oxide fine particles are mixed. The apparatus used for mixing is not particularly limited, and any known mixing apparatus such as a planetary mixer, a kneader or a ruder may be used as long as it can uniformly disperse the fine particles in the polymer dope. The shape, output, and capacity are not particularly limited. Further, the mixing conditions such as output and time can be appropriately adjusted in consideration of the shape, output and capacity of the apparatus.
In order to efficiently disperse the iron (III) oxide fine particles in the polymer dope, a slurry in which the iron (III) fine particles are previously dispersed in the amide solvent used for the polymer dope is mixed with the polymer dope. It is preferable. The concentration of the iron (III) oxide fine particle slurry at that time is not particularly limited in consideration of the amount of iron (III) oxide fine particles finally contained in the fiber, but the dispersibility of the fine particles in the slurry is not limited. From the viewpoint of handleability, the content is preferably 1% by mass to 20% by mass, more preferably 2% by mass to 15% by mass, and still more preferably 3% by mass to 10% by mass.

  Also, the amount of iron oxide (III) fine particle slurry mixed with the polymer dope is particularly limited in consideration of the amount of fine particles in the fiber finally obtained and the concentration of fine particles in the iron oxide (III) fine particle slurry. However, it is preferably 10 to 50 parts by mass, more preferably 12 to 40 parts by mass, and still more preferably 15 to 30 parts by mass with respect to 100 parts by mass of the polymer dope.

(Mixing of masterbatch and polymer solution)
Next, a polymer dope in which iron (III) fine particles are uniformly mixed and a polymer dope not containing iron (III) fine particles are mixed. Regarding the mixing method, in consideration of workability, fiber productivity, etc., a known static mixer is most preferable, and its shape, type, length, etc. are particularly limited as long as they can be mixed uniformly. is not. In addition, as the method, a pipe for feeding a polymer dope containing iron (III) fine particles is joined to a pipe for feeding a polymer dope containing no iron (III) fine particles, and the pipes are joined. A method of providing various static mixers on the downstream side is preferable, but is not limited thereto.

  The mixing ratio of the polymer dope in which iron (III) fine particles are uniformly mixed and the polymer dope not containing iron (III) fine particles is the same as the iron oxide in the polymer dope in which iron (III) fine particles are uniformly mixed ( III) Although depending on the fine particle concentration, the amount of iron (III) fine particles in the finally obtained wholly aromatic copolyamide fiber is 0.1 to 10 parts by mass with respect to 100 parts by mass of the wholly aromatic copolyamide polymer, It is necessary to adjust so that it may become 0.5-5 mass parts preferably. When the amount of iron (III) oxide fine particles in the wholly aromatic copolyamide fiber is less than 0.1 parts by mass with respect to 100 parts by mass of the wholly aromatic copolyamide polymer, the original hue of the fiber becomes dominant, It is not preferable because it is difficult to obtain a fiber having a hue. On the other hand, when the amount of iron (III) fine particles in the wholly aromatic copolyamide fiber exceeds 10 parts by mass with respect to 100 parts by mass of the wholly aromatic copolyamide polymer, the iron (III) oxide fine particles in the fiber Even if the dispersion is uniform, the amount of the wholly aromatic copolyamide polymer itself that contributes to the strength in the fiber is reduced, which makes it difficult to achieve a tensile strength of 18 cN / dtex or more. If the amount of iron (III) oxide fine particles in the wholly aromatic copolyamide fiber can be adjusted to be in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the wholly aromatic copolyamide polymer, the mixing ratio is particularly high. It is not limited.

(Yarn making)
Next, yarn production is performed using a para-type wholly aromatic copolyamide polymer dope mixed with iron (III) oxide fine particles.
First, the polymer dope is discharged from the spinneret. The hole diameter, nozzle length, number of holes, material, and the like of the spinneret used for discharging are not particularly limited, and can be appropriately adjusted in consideration of the fiber diameter, the number of single yarns, the spinnability, and the like of the obtained fiber. .
The temperature of the polymer dope when passing through the spinneret and the temperature of the spinneret are not particularly limited because they can be appropriately adjusted depending on the concentration and viscosity of the polymer dope to be used. Considering discharge pressure, polymer dope deterioration, and the like, 75 to 120 ° C. is preferable.

  Next, the polymer dope discharged from the spinneret is coagulated in a coagulating liquid. At this time, when the temperatures of the spinneret and the coagulating liquid are greatly different, when the spinneret and the coagulating liquid come into contact with each other, the respective temperatures change and it becomes difficult to control, so that an air gap can be provided. The length of the air gap at this time is not particularly limited, but is preferably 5 to 15 mm from the viewpoints of single yarn adhesion, temperature controllability, spinnability, and the like. The coagulation liquid used here is an aqueous solution of an amide solvent used for polymer dope, and its temperature and solvent concentration are not particularly limited. As long as there is no problem with the above, it can be adjusted as appropriate.

  Next, the solidified yarn is washed with water. The purpose of this washing step is to remove as much of the amide solvent in the yarn as possible using water. The washing conditions are not particularly limited, and the number of washing baths, the temperature, and the like can be appropriately adjusted as long as NMP in the yarn can be sufficiently removed.

  Next, the washed fiber is dried. The drying conditions at this time are not particularly limited, and there is no problem as long as moisture contained in the fibers can be sufficiently removed. However, in consideration of workability and deterioration of the fibers due to heat, the temperature is 150 to 250 ° C. preferable. For drying, either a contact-type drying apparatus such as a roller or a non-contact type drying apparatus in which fibers pass through a drying furnace can be used.

  Next, the dried fiber is hot-drawn. In this step, the object is to highly orient polymer molecules in the fiber and impart strength by hot drawing of the fiber. The thermal stretching temperature at this time is not particularly limited as long as sufficient stretching and strength are exhibited, but is preferably 300 to 600 ° C, more preferably 320 ° C to 580 ° C, and most preferably 350 to 550. ° C. The draw ratio in this hot drawing step is preferably 5 to 15 times, but is not particularly limited to this range as long as sufficient high strength can be achieved. Further, in this heat stretching process, there is no particular problem even if it is performed in multiple stages as necessary. An apparatus used for hot drawing of the fiber includes a contact-type hot plate and a non-contact type furnace, but is not particularly limited. The temperature of the fiber is raised to a predetermined temperature, and a predetermined magnification is used. Any apparatus can be used as long as it can be stretched.

  Then, if necessary, an oil agent is applied for the purpose of imparting charge suppression or lubricity to the fiber, and finally wound with a winder. There are no particular limitations on the type of oil agent to be applied and the amount to be applied, and the oil agent can be appropriately adjusted in consideration of the use of the fiber and the handleability of the fiber. Moreover, about the winding method with a winder, it can wind by adjusting winding conditions, such as tension | tensile_strength and contact pressure, suitably using a well-known winder.

[Physical properties of para-type aromatic copolyamide fiber]
(Hue)
The para-type wholly aromatic copolyamide fiber thus obtained has an average L ^* value a ^* value b ^* value of the color system representing the hue of L ^* values of 40 to 65, preferably 45 to 60, preferably a ^*. The value is +20 to +30, preferably +20 to +25, b ^* value is +12 to +18, preferably +15 to +18, and the standard deviation thereof is L ^* value of 1.0 or less, preferably 0.8 or less, a ^{* The} value is 0.5 or less, preferably 0.3 or less, and the b ^* value is 0.3 or less, preferably 0.25 or less.
In order to set the average value of the L ^* value a ^* value b ^* value of the obtained fiber and the standard deviation of the hue within the above range, the polymer dope and the oxide in which iron (III) fine particles as inorganic fine particles are uniformly dispersed are used. What is necessary is just to consider the ratio of the iron (III) fine particles to be uniformly mixed with the polymer dope not containing iron (III) fine particles and to be added.

(Tensile strength)
Moreover, the tensile strength of the wholly aromatic copolyamide fiber used in the present invention is 18 cN / dtex or more and less than 25 cN / dtex, preferably 20 to 25 cN / dtex. If it is less than 18 cN / dtex, it is difficult to achieve a certain level of tear strength as protective clothing, which is not preferable. On the other hand, it is difficult to make it 25 cN / dtex or more in production. The tensile strength of the fiber can be controlled to be 18 cN / dtex or more and less than 25 cN / dtex by controlling, for example, the draw ratio and the ratio of iron (III) fine particles dispersed to the polymer component in the fiber.

<Method of manufacturing protective clothing>
(Crimping)
The fiber used in the protective garment of the present invention is crimped. Examples of the crimping method include known methods such as gear crimping and indentation crimping. However, the crimping method is not limited to these, and can be appropriately applied depending on the type of fiber used. The crimped yarn obtained in this way is cut into a fixed length staple fiber. The cut length can be adjusted as appropriate in consideration of process passability in the subsequent process of obtaining a spun yarn by blending, or in the process of passing the card and processing it into a non-woven fabric. Although it is -80 mm, it is not limited to these.

(spinning)
Next, the obtained staple fibers are blended to obtain a spun yarn. For blending, a known method can be applied as it is, but the mixing ratio of the fibers contained at that time is at least iron (III) oxide fine particles from the viewpoint of mechanical properties and washing durability of the protective clothing to be obtained. The proportion of the para-type wholly aromatic copolyamide fiber to be contained must be 40% by mass or more based on the total blended fiber. When the proportion of para-type wholly aromatic copolyamide fiber containing iron oxide (III) fine particles is less than 40% by mass with respect to the total blended fiber, mechanical properties such as washing durability and tear strength of the resulting protective clothing are obtained. This is not preferable because it is not satisfactory. The blending ratio of the other fibers is not particularly limited, and can be appropriately adjusted in consideration of the mechanical properties, washing durability, wear resistance, flame resistance, texture, etc. of the obtained protective clothing. . The yarn count of the obtained spun yarn is not particularly limited, and can be appropriately adjusted in consideration of the weaving property and knitting property when processing into a subsequent fabric, but generally the yarn count is 10-60. .

(Fabric processing)
Next, the obtained spun yarn is processed into a fabric. As the type of fabric, any of woven fabrics, knitted fabrics, and nonwoven fabrics made of staple fibers can be applied, and the woven structure and knitted structure are not particularly limited. It can be applied as appropriate in consideration. The basis weight is not particularly limited, but is preferably 100 to 800 g / m ² from the viewpoints of handleability and easy sewing.

(Sewing)
Finally, the obtained fabric is sewn to produce protective clothing. The sewing method can be sewn by a generally known method in consideration of mechanical properties, maneuverability, texture and the like. Also, there is no problem even if a plurality of fabrics are laminated and sewn. Furthermore, for the purpose of imparting water repellency and abrasion resistance to protective clothing, the surface of the fabric can be subjected to surface treatment by coating or spraying, and from the viewpoint of clothing comfort, for the purpose of imparting moisture permeability and waterproofness. In addition, there is no problem even if a thin film having moisture permeability and waterproof properties is applied between the laminated fabrics.

<Physical properties of protective clothing>
(Washing durability)
The protective clothing thus obtained has a wash durability evaluated in accordance with JIS L0844 A-2 of grade 4 or higher, preferably grade 4.5 or higher as determined by gray scale. If the color fading is less than 4th grade, it is difficult to achieve high washing durability as protective clothing, which is not preferable. In order to make the protective garment a grade 4 or more, the para-type wholly aromatic copolyamide fiber of the present invention having a certain hue may be mixed by 40% by mass or more with respect to the total mass of the protective garment.

(Hue)
Further, protective clothing of the invention, the average ^{L *} value ^{a *} value ^{b *} value of the color system representing the hue, respectively, the ^{L *} value is 40 to 65, ^{a *} value +. 20 to + 30, ^{b *} values Is preferably +12 to +18. More preferably, the L ^* value is 45 to 60, the a ^* value is +20 to +25, and the b ^* value is +15 to +18. In order to bring the average of the L ^* value a ^* value b ^* value within the above range, the mixing ratio of fibers to be blended and the hue of each fiber may be controlled within a certain range.

(Tear strength)
Further, the protective clothing of the present invention preferably has a tear strength evaluated in accordance with JIS L1096 of 90 N or more, more preferably 100 N or more. If it is less than 90 N, the protective clothing is easily damaged by scratching or the like, which is not preferable. In order to increase the tear strength to 90 N or more, para-type wholly aromatic copolyamide fibers having a tensile strength of 18 cN / dtex or more and less than 25 cN / dtex may be mixed by 40 mass% or more with respect to the total mass of the protective clothing.

(Limited oxygen index)
Furthermore, the protective clothing of the present invention preferably has a limiting oxygen index (LOI value) of 25 or more measured in accordance with JIS K7201-2. If the limiting oxygen index is less than 25, it is not preferable because it is easily burned when used as protective clothing, and the safety of a worker wearing it cannot be secured. In order to set the critical oxygen index to 25 or more, para-type wholly aromatic copolyamide fiber may be mixed by 40% by mass or more based on the total mass of the protective clothing.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.
<Measurement and evaluation method>
Each physical property value in Examples and Comparative Examples was measured and evaluated by the following methods.

(1) Intrinsic viscosity of the polymer The polymer was dissolved in 98% sulfuric acid so that the polymer concentration became 0.5 g / dl, and measured at 30 ° C. using an Ostwald viscometer.

(2) Average particle diameter of iron (III) oxide fine particles (D50)
The fine particles were dispersed in water, and the particle size of the fine particles was measured using a laser diffraction particle size distribution analyzer (device name: SALD-200VER, manufactured by Shimadzu Corporation). The particle diameter of 100 samples was measured, and the particle diameter corresponding to the 50th particle from the smallest particle diameter was defined as “average particle diameter”.

(3) Washing durability of protective clothing In accordance with JIS L0844 A-2, the washing durability of protective clothing was evaluated under the following conditions.
(Measurement condition)
Temperature: 50 ° C
Time: 30 minutes / time Test piece: 10 cm × 4 cm
Judgment of discoloration: In accordance with JIS L0801, the test piece before and after washing was graded using a gray scale.

(4) Hue of fiber and protective clothing Regarding the fibers used and the protective clothing obtained, a color difference meter (device name: CR-400, manufactured by Konica Minolta Co., Ltd.) was used, and L ^* values a ^* values were obtained for 10 different places. b ^* values were measured. Furthermore, about the measurement result, each average value and standard deviation were computed.

(5) Tear strength of protective clothing In accordance with JIS L1096, the tear strength of protective clothing was measured under the following conditions.
(Measurement condition)
Test method: Method A-1 (single tongue method)
Test piece: 10 cm x 25 cm
Test speed: 150mm / min

(6) Limiting oxygen concentration (LOI value) of protective clothing
Based on JIS K7201-2, the LOI value of protective clothing was measured under the following conditions.
(Measurement condition)
Temperature: Room temperature Test piece: 14 cm x 5.2 cm
Flame contact time: 5 seconds x 6 times

(7) Tensile strength of fiber Using a tensile tester (manufactured by INSTRON, trade name: INSTRON, model: 5565 type), in accordance with ASTM D885, a tensile test is performed under the following conditions using a yarn test chuck. went.
(Measurement condition)
Temperature: Room temperature Test piece: 75cm
Test speed: 250 mm / min Distance between chucks: 500 mm

<Example 1>
First, 94 parts by mass of NMP and red iron oxide (III) fine particles (manufactured by Toda Kogyo Co., Ltd., product name: Toda Color 130ED, average particle diameter (D50) = 0.4 μm, specific gravity = 5.1) 6 parts by mass 30 parts by mass of a slurry added with copolyparaphenylene 3,4'-oxydiphenylene terephthalamide (terephthalic acid dichloride, paraphenylenediamine, 3,4'-diaminodiphenyl ether in a molar ratio of 2: 1: 1 A para-type wholly aromatic copolyamide polymer obtained by copolymerization, 70 parts by mass of a 6% by mass NMP solution of intrinsic viscosity (IV) = 3.4) was mixed for 1.5 hours with a planetary mixer, and iron oxide (III ) A polymer dope having a mass fraction of fine particles of 30% by mass relative to the polymer mass was obtained.

  Next, a polymer dope containing iron (III) oxide fine particles and a polymer dope containing fine particles of iron oxide (III) are fed in the course of passing through a Kenex type static mixer. The polymer dope containing no was mixed uniformly. In addition, the amount of each liquid fed at this time was 125 parts by mass for polymer dope containing iron (III) oxide fine particles and 2,375 parts by mass for polymer dope not containing fine particles.

Next, the polymer dope containing the obtained iron (III) oxide fine particles was discharged through a spinneret heated to 105 ° C. having a pore diameter of 0.3 mm and a pore number of 1,000, coagulation, water washing, drying, A fiber was obtained through a hot drawing process. At this time, the fineness of the fiber was 1,670 dtex, the number of fibers was 1,000, and the content of iron (III) fine particles with respect to the fiber mass was 1.5 mass%. Further, the tensile strength of the fiber obtained at this time is 23.1cN / dex, also respectively the ^{L *} value ^{a *} value ^{b *} value of the color system ^{L *} value representing the hue 56.2, ^{a *} The value was +22.5, the b ^* value was +16.9, and the hue standard deviation was L ^* value 0.24, a ^* value 0.16, and b ^* value 0.12, respectively. .
Next, the obtained fiber was crimped and then cut to obtain a staple fiber. The cut length at this time was 51 mm. Furthermore, a 20th spun yarn was obtained using this staple fiber.

Finally, using this spun yarn, weaving was performed so as to form a 2/1 twill, and a woven fabric was obtained. At this time, the basis weight of the woven fabric was 495 g / m ² . Table 1 shows the measurement results of washing durability, hue, tear strength, and LOI value of the protective clothing obtained.

<Example 2>
30 parts by mass of slurry obtained by adding 21 parts by mass of the same iron (III) oxide fine particles as in Example 1 to 79 parts by mass of NMP, and 21% by mass of polymetaphenylene isophthalamide (intrinsic viscosity (IV) = 1.35) 70 parts by mass of the NMP solution was mixed with a planetary mixer for 1.5 hours to obtain a polymer dope in which the mass fraction of iron (III) oxide fine particles was 30% by mass with respect to the polymer mass.
Next, a polymer dope containing iron (III) oxide fine particles and a polymer dope containing fine particles of iron oxide (III) are fed in the course of passing through a Kenex type static mixer. The polymer dope containing no was mixed uniformly. In addition, the amount of each liquid fed at this time was 125 parts by mass for polymer dope containing iron (III) oxide fine particles and 2,375 parts by mass for polymer dope not containing fine particles.

Next, the obtained polymer dope containing iron (III) oxide fine particles was discharged through a spinneret heated to 85 ° C. having a pore diameter of 0.07 mm and a pore number of 10,000, and coagulated, washed with water, and stretched with boiling water. Fibers were obtained through the steps of drying, wet heat stretching. In addition, the fineness of the fiber at this time was 16,700 dtex, the number of fibers was 10,000, and the content of iron (III) fine particles with respect to the fiber mass was 1.5 mass%. The tensile strength of the fiber obtained in this case 4.5 cN / dex, also respectively the ^{L *} value ^{a *} value ^{b *} value of the color system ^{L *} value representing the hue 51.3, ^{a *} value +25.0, b ^* value was +16.2, and the standard deviation of the hue was L ^* value 0.33, a ^* value 0.22, and b ^* value 0.19, respectively.

Next, the obtained fiber was crimped and then cut to obtain polymetaphenylene isophthalamide staple fiber. The cut length at this time was 51 mm.
On the other hand, PPTA staple fiber (Teijin Techno Products Co., Ltd., Twaron 1072, fineness = 1.7 dtex, cut length = 50 mm) was dyed under the following conditions.
Dyeing conditions: 135 ° C., 60 minutes Dye: C.I. I. disperse Red 60 (manufactured by Sumika Chemtex, Sumikaron Red E-FBL) 5% owf
Nitric acid Na: 25 g / L
Acetic acid: 0.5 g / L
Benzyl alcohol: 50 g / L
Bath ratio: 1:20

After dyeing, it was washed under the following conditions and sufficiently dried to obtain PPTA staple fibers.
Washing conditions: 80 ° C., 20 minutes Score roll # 400: 1 g / L
Incidentally, the tensile strength of staple fiber obtained in this case 16.3cN / dex, also respectively the ^{L *} value ^{a *} value ^{b *} value of the color system ^{L *} value representing the hue 55.3, ^{a *} value Was +23.6, the b ^* value was +15.9, and the standard deviations of the hues were the L ^* value of 0.33, the a ^* value of 0.22, and the b ^* value of 0.19, respectively.

Next, 70 parts by mass of the copolyparaphenylene-3,4'-oxydiphenylene terephthalamide staple fiber obtained in Example 1, 10 parts by mass of the previously prepared polymetaphenylene isophthalamide staple fiber, and PPTA 20 parts by mass of this staple fiber was blended to obtain 20th spun yarn. And the woven fabric was obtained by the same method as Example 1, this was sewn, and the protective clothing was obtained. At this time, the basis weight of the woven fabric was 501 g / m ² . Table 1 shows the measurement results of washing durability, hue, tear strength, and LOI value of the protective clothing obtained.

<Example 3>
Spun yarn, woven fabric, protective clothing in the same manner as in Example 2 except that 40 parts by mass of staple fiber of copolyparaphenylene 3,4'-oxydiphenylene terephthalamide and 60 parts by mass of staple fiber of PPTA were used. Got. At this time, the basis weight of the woven fabric was 500 g / m ² . Table 1 shows the measurement results of washing durability, hue, tear strength, and LOI value of the protective clothing obtained.

<Example 4>
Example, except that 40 parts by mass of copolyparaphenylene-3,4'-oxydiphenylene terephthalamide staple fiber, 30 parts by mass of polymetaphenylene isophthalamide staple fiber, and 30 parts by mass of PPTA staple fiber were used. Spun yarn, woven fabric, and protective clothing were obtained in the same manner as 2. At this time, the basis weight of the woven fabric was 503 g / m ² . Table 1 shows the measurement results of washing durability, hue, tear strength, and LOI value of the protective clothing obtained.

<Comparative Example 1>
Spinned yarn, woven fabric, protective clothing in the same manner as in Example 2 except that 30 parts by mass of staple fiber of copolyparaphenylene 3,4'-oxydiphenylene terephthalamide and 70 parts by mass of staple fiber of PPTA were used. Got. At this time, the basis weight of the woven fabric was 500 g / m ² . Table 1 shows the measurement results of washing durability, hue, tear strength, and LOI value of the protective clothing obtained.

<Comparative example 2>
A spun yarn, woven fabric and protective clothing were obtained in the same manner as in Example 2 except that 50 parts by mass of the staple fiber of polymetaphenylene isophthalamide and 50 parts by mass of the staple fiber of PPTA were used. At this time, the basis weight of the woven fabric was 498 g / m ² . Table 1 shows the measurement results of washing durability, hue, tear strength, and LOI value of the protective clothing obtained.

<Comparative Example 3>
A spun yarn, woven fabric, and protective clothing were obtained in the same manner as in Example 2 except that the PPTA staple fiber was changed to 100 parts by mass. At this time, the basis weight of the woven fabric was 502 g / m ² . Table 1 shows the measurement results of washing durability, hue, tear strength, and LOI value of the protective clothing obtained.

<Comparative example 4>
A spun yarn, woven fabric, and protective clothing were obtained in the same manner as in Example 2 except that 100 parts by mass of the staple fiber of polymetaphenylene isophthalamide was used. At this time, the basis weight of the woven fabric was 499 g / m ² . Table 1 shows the measurement results of washing durability, hue, tear strength, and LOI value of the protective clothing obtained.

Since the protective clothing of the present invention has a specific hue and mechanical properties such as high washing durability and strength, it has a high design and machine that could not be developed with the original hue of the polymer. It is particularly useful in protective clothing applications such as fire-fighting clothing and bulletproof / bladeproof materials that require special physical properties.

Claims (5)

The constituent fiber contains iron (III) oxide fine particles having an average particle diameter (D50) of 0.05 μm to 2 μm at least, and the average value of the L ^* value a ^* value b ^* value of the color system representing the hue is each ^{L *} value from 40 to 65, an ^{a *} value of +. 20 to + 30, ^{b *} value + 12 + 18, and the standard deviation of the hue is ^{L *} value, respectively 1.0 or less, ^{an a *} value of 0. 5 or less, including a para-type wholly aromatic copolyamide fiber having a b ^* value of 0.3 or less and a tensile strength of 18 cN / dtex or more and less than 25 cN / dtex, and the blending ratio is based on the total mass A protective garment having a mass of 40% by mass or more, wherein the washing durability evaluated in accordance with JIS L0844 A-2 is a grade 4 or higher color change by gray scale determination. The average value of the L ^* value a ^* value b ^* value of the color system representing the hue of the protective clothing is L ^* value of 40 to 65, a ^* value of +20 to +30, and b ^* value of +12 to +18. The protective suit according to claim 1.   The protective clothing according to claim 1 or 2, wherein the tear strength of the protective clothing is 90 N or more.   The protective clothing according to any one of claims 1 to 3, wherein the protective clothing has a limiting oxygen index (LOI value) measured in accordance with JIS K7201-2 of 25 or more.   The protective clothing according to any one of claims 1 to 4, wherein the para-type wholly aromatic copolyamide is copolyparaphenylene 3,4'-oxydiphenylene terephthalamide.