JP6523026B2 - Black meta-type wholly aromatic polyamide fiber - Google Patents

Description

  The present invention relates to a black meta-type wholly aromatic polyamide fiber using an infrared ray transmitting black dye.

The fibers of a meta-type wholly aromatic polyamide (hereinafter sometimes abbreviated as “meta-aramid”) represented by poly-meta-phenylene isophthalamide have excellent heat resistance because most of the molecular skeleton is composed of an aromatic ring. Properties such as flame retardancy and dimensional stability. Taking advantage of these properties, meta-aramid fibers are suitably used in industrial applications, protective clothing applications and the like.
Among them, unattached meta-aramid fibers using a black pigment are widely used as protective clothing in fire fighting, military, manufacturing sites and the like because they have good light fastness and deep color forming properties.
However, since black base-attached meta-aramid fibers are generally colored using a pigment containing carbon black as a main component, the temperature of the clothes is significantly increased due to the absorption of infrared rays in a working environment receiving radiant heat from sunlight or flames. , Had a problem that it interferes with the activities of firefighters and workers.

JP, 2006-241640, A

  The present invention has been made in view of the above background art, and an object thereof is to provide a black meta-type wholly aromatic polyamide fiber in which heat absorption is suppressed.

  The present inventors have intensively studied in view of the above problems. As a result, a specific amount of infrared transmitting type black dye and pigment is blended, the compounding amount of the infrared non-transparent type black dye and pigment is set to a specific amount or less, and the transmittance in the infrared range of wavelength 1000 to 2000 nm is within the specific range. Thus, the inventors have found that the above problems can be solved, and have completed the present invention.

That is, in the present invention, the content of the infrared ray transmitting type black dye and pigment is 0.2 to 10% by weight, the content of the infrared ray impermeable type black dye and pigment is 0.1% by weight or less, and It is a black meta-type wholly aromatic polyamide fiber characterized by satisfying the following conditions .
The average of the transmittance at a wavelength of 1,000 to 1,500 nm is 50% or more.
30% or more of the average of the transmittance | permeability in wavelength 1,500-2,000 nm.
The thermal storage property by the measuring method of the following description should be 50-53 degreeC.
Thermal storage
Under an atmosphere of 20 ° C and 65% RH, using lighting (IR 100 V / 125 W), the sample is a 4 cm × 4 cm hole in cardboard and used with the sample attached, and a 15 cm × 15 cm opening The sample was placed on a 1 cm thick acrylic plate, the distance between the illumination and the sample was 30 cm, and the temperature on the back of the sample was measured 15 minutes after the start of irradiation.
And as another invention, it is a method for producing a black meta-type wholly aromatic polyamide fiber, wherein 0.2 to 10% by weight of an infrared transmitting type black dye and pigment, and an infrared ray non-transparent black dye and pigment are 0. It is a manufacturing method of a black meta-type wholly aromatic polyamide fiber including the process made to contain 1% by weight or less and the heat treatment temperature in the dry heat treatment process after the drying process is in the range of 250 to 400 ° C.

The black meta-type wholly aromatic polyamide fiber of the present invention becomes a fiber with a small temperature rise due to the radiation of infrared rays by coloring it using an infrared ray transmitting type black coloring pigment. That is, in addition to the inherent properties of the meta-type wholly aromatic polyamide fiber of flame retardancy and heat resistance, the product rises even when it receives radiation including infrared rays from various heat sources such as sunlight and flame. You can control the temperature.
Therefore, a garment made using the black meta-type wholly aromatic polyamide fiber of the present invention exhibits excellent non-heat storage ability in a working environment receiving heat radiation, so protective clothing such as fire fighting clothing and heat-resistant working clothing. It can be suitably used as

<Structure of meta-type wholly aromatic polyamide>
The meta-type wholly aromatic polyamide constituting the black meta-type wholly aromatic polyamide fiber of the present invention is composed of a meta-type aromatic diamine component and a meta-type aromatic dicarboxylic acid component, and the object of the present invention is In the range which does not inhibit, what copolymerized other copolymerization components, such as para type, for example may be used.
Particularly preferably used in the present invention is a meta-type wholly aromatic polyamide containing a metaphenylene isophthalamide unit as a main component from the viewpoint of mechanical properties and heat resistance. As a meta-type wholly aromatic polyamide composed of metaphenylene isophthalamide units, the metaphenylene isophthalamide unit is preferably 90 mol% or more of all repeating units, more preferably 95 mol% or more, particularly preferably It is 100 mol%.

<Method of producing meta-type wholly aromatic polyamide>
The method for producing the meta-type wholly aromatic polyamide constituting the black meta-type wholly aromatic polyamide fiber of the present invention is not particularly limited. For example, a meta-type aromatic diamine component and a meta-type aromatic dicarboxylic acid chloride component It can be produced by solution polymerization or interfacial polymerization using as a raw material.
The molecular weight of the meta-type wholly aromatic polyamide is not particularly limited as long as it can form a fiber. In general, in order to obtain a fiber with sufficient physical properties, a polymer having an intrinsic viscosity (I.V.) in the range of 1.0 to 3.0 when measured at 30 ° C. with a polymer concentration of 100 mg / 100 mL sulfuric acid in concentrated sulfuric acid Suitable, polymers in the range of 1.2 to 2.0 are particularly preferred.

<Method for producing black meta-type wholly aromatic polyamide fiber>
The black meta-type wholly aromatic polyamide fiber of the present invention is produced using, for example, the meta-type wholly aromatic polyamide obtained by the above-mentioned production method, etc. It can manufacture through a process, a washing process, a drying process, and a dry heat treatment process.

[Spinning solution preparation process]
In the spinning solution preparation step, the meta-type wholly aromatic polyamide is dissolved in an amide solvent, and the dye and pigment necessary for obtaining the black meta-type wholly aromatic polyamide of the present invention are added to obtain a spinning solution (meta type Preparation of the wholly aromatic polyamide polymer solution). In preparation of the spinning solution, an amide-based solvent is usually used, and examples of the amide-based solvent used include N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc) and the like. . Among these, it is preferable to use NMP or DMAc from the viewpoint of solubility and handling safety.
As the solution concentration, an appropriate concentration may be appropriately selected from the viewpoint of spinnability and solubility of the polymer in the subsequent step of spinning and coagulation, and, for example, the polymer is polymetaphenylene isophthalamide and the solvent is NMP. Usually, it is preferable to set it as 10-30 mass% in case of.

(Dye and pigment)
In the present invention, a black dye of infrared transmission type is used. Dyeing pigments may be used alone or in combination of two or more, and the combination of dyes and pigments in the case of using two or more kinds is particularly limited as long as the desired hue can be obtained. It is not a thing. The mixing method of the meta-type wholly aromatic polyamide and the dye / pigment is not particularly limited. For example, an amide-based solvent slurry in which the dye / pigment is uniformly dispersed in an amide-based solvent is prepared. A method of adding the meta-type wholly aromatic polyamide to a solution in which the amide-based solvent is dissolved, or a method of directly adding the dye and pigment powder to a solution in which the meta-type wholly aromatic polyamide is dissolved in the amide-based solvent may be mentioned.

(Dye and pigment content)
The blending amount of dyes and pigments is 0.2 to 10.0% by mass, preferably 0.5 to 5.0% by mass or less, and more preferably 1.0 to 2.5% by mass with respect to the meta-type wholly aromatic polyamide. It is less than mass%. If the amount is more than 10.0% by mass, the spinnability is significantly deteriorated, and the physical properties of the obtained fiber are also deteriorated.

(Infrared opaque black pigment)
The black meta-type wholly aromatic polyamide fiber of the present invention may contain an infrared-impermeable black dye / pigment in addition to the above-mentioned infrared ray-transmittable black dye / pigment. The infrared ray-impermeable black dyestuff is preferably carbon black, and it is essential that the compounding amount thereof is 0.1% by weight or less with respect to the black meta-type wholly aromatic polyamide fiber. If it is 0.1% by weight or more, the transmittance in the infrared region is lowered, which is not preferable.

[Spinning and coagulation process]
In the spinning and coagulation step, the spinning solution (meta-type wholly aromatic polyamide polymer solution) prepared above is spun into the coagulation solution to coagulate, that is, a coagulated yarn is formed by a wet spinning method. In the spinneret used, the number of spinning holes, arrangement state, pore shape, etc. need not be particularly limited, but from the viewpoint of productivity and spinnability, the number of holes is 10,000 to 30,000, and the spinning pore diameter is 0.04. It is preferred to use a multi-hole spinneret for spufs of -0.7 mm. The temperature of the polymer solution at the time of spinning from the spinneret is preferably in the range of 25 to 40 ° C.

  In the above-mentioned wet spinning method, in order to obtain fibers from a stock solution of spinning solution in which a polymer is dissolved in an amide solvent, the amide solvent remains in the fibers necessarily obtained. The residual solvent in the fiber is not preferable for safety because it evaporates during processing and use under high temperature conditions. Therefore, it is necessary to sufficiently reduce the amount of residual solvent contained in the resulting fiber, and to make the structure of the coagulated yarn formed in the coagulation step of the spinning and coagulation process a homogeneous porous structure without a skin layer. It is extremely important. The amount of the solvent remaining in the fiber of the finally obtained black meta-type wholly aromatic polyamide fiber of the present invention is preferably 0.1% by weight or less, more preferably 0.08% by weight.

  In order to obtain a porous fibrous material having a uniform structure, it is important to set the composition and temperature of the coagulating liquid used in the coagulating bath to a specific condition, and the coagulating liquid substantially comprises an amide solvent and water. It is preferable to set it as the aqueous solution which consists of two components. However, when the polymer solution contains inorganic salts such as calcium chloride and calcium hydroxide, since they are extracted into the coagulating liquid, the coagulating liquid actually contains a small amount of these salts. The preferred concentration of salts in industrial practice is in the range of 0.3% by weight to 10% by weight with respect to the whole coagulation liquid. In order to make mineral salt concentration less than 0.3 mass%, since the recovery cost for the refinement | purification in the recovery process of coagulation | solidification liquid becomes very high, it is not suitable. On the other hand, when the concentration of the inorganic salt exceeds 10% by mass, the coagulation rate is slowed, so that the fiber before the formation of the porous immediately after being discharged from the spinneret tends to be fused, and Since the coagulation time is long, it is not preferable because the coagulation facility must be enlarged.

As the amide solvent used for the coagulating solution, any solvent which dissolves meta-type wholly aromatic polyamide polymer and mixes well with water can be used, and in particular, N-methyl-2-pyrrolidone (NMP), Dimethyl acetamide (DMAc), dimethylformamide (DMF), dimethyl imidazolidinone etc. can be used suitably.
The concentration of the amide-based solvent in the coagulating solution (hereinafter referred to as the coagulating solution concentration) is a condition that largely affects the porous structure of the coagulated yarn. In particular, the concentration of the coagulating liquid brought into contact with the polymer solution immediately after being discharged from the die must be strictly controlled since it greatly affects the porous structure as well as the fiber quality. Therefore, it is necessary to set the coagulation liquid concentration in the vicinity of the spinneret to an appropriate concentration at which a target fiber structure can be obtained according to the polymer solution concentration and the degree of polymerization of the polymer.

In order to obtain a uniform porous structure without spots, it is preferable to set the central value of the coagulation liquid concentration in the range of 45.0 to 60.0%. Below this range, a very large void is likely to be formed in the coagulated fiber, which tends to cause a subsequent single thread breakage. In addition, a structure having a thick skin is formed, the washing efficiency in the washing step is reduced, and it becomes difficult to make the residual solvent amount of the obtained fiber 0.1% by weight or less. On the other hand, coagulation does not proceed under conditions exceeding this range, and fusion of fibers tends to occur.
In addition, the temperature of the coagulation bath is closely related to the composition of the coagulation liquid, and needs to be strictly controlled as in the case of the amide solvent concentration. The coagulation liquid concentration depends on the coagulation time, but it is preferable to set the central value in the range of 10 to 35 ° C.

[Plastic drawing process]
In the plastic stretching step, the fiber bundle composed of the porous coagulated yarn obtained by the coagulation step is stretched in air or in a bath. In the present invention, it is preferable to draw at a draw ratio of 3.5 to 5.0. The draw ratio as used herein means the ratio of the fiber length after treatment to the fiber length before the draw treatment. By drawing at a high magnification, the micropores of the porous coagulated yarn are drawn down, the densification in the heat treatment step described later proceeds favorably, and the mechanical properties such as strength and elastic modulus of the obtained fiber are improved. be able to. In addition, when drawing is performed at an extremely high magnification, breakage of single yarn is likely to occur during drawing, and it is difficult to obtain fibers of good quality.

[Washing process]
In the washing step, the fiber that has undergone the plastic drawing step is sufficiently washed. The washing is preferably carried out in a multistage washing bath because it affects the quality of the resulting fiber. In particular, the temperature of the washing solution in the washing step and the concentration of the amide solvent in the washing solution affect the state of extraction of the amide solvent from the fibers and the state of penetration of water from the washing bath into the fibers. For this reason, it is preferable to control the temperature condition and the concentration condition of the amide solvent by setting the washing process in multiple stages also for the purpose of making them in the optimum state.
The temperature conditions and the concentration conditions of the amide solvent are not particularly limited as long as they can satisfy the quality of the finally obtained fiber, but when the first washing bath has a high temperature of 60 ° C. or more, water is The infiltration of the fiber into the fiber rapidly occurs, causing a large void in the fiber, resulting in deterioration of the quality. Therefore, it is preferable to set the first washing bath to 30 ° C. or less. Subsequently, it is preferable to wash with warm water at 50 to 90 ° C.

[Drying process]
In the drying step, the fiber that has undergone the washing step is dried. The method of the drying treatment is not particularly limited, but a method using a heat roller is general from the viewpoint of the drying efficiency. The drying temperature is typically about 120 to 160 ° C.

[Dry heat treatment process]
In the dry heat treatment step, the fibers subjected to the drying step are heat treated at a high temperature to densify the porous fiber structure. The method of dry heat treatment is not particularly limited, and examples thereof include methods using a heat plate, a heat roller, and the like. Through the dry heat treatment, finally, the black meta-type wholly aromatic polyamide fiber of the present invention can be obtained.
The heat treatment temperature in the dry heat treatment step is preferably in the range of 250 to 400 ° C. If the dry heat treatment temperature is less than 250 ° C., it is difficult to fully densify the porous fibers, and the mechanical properties of the resulting fibers become insufficient. On the other hand, if the dry heat treatment temperature is a high temperature exceeding 400 ° C., the surface of the fiber is thermally deteriorated to deteriorate the grade, which is not preferable.

  The draw ratio in the dry heat treatment process is closely related to the development of the strength of the obtained fiber. Although a draw ratio can select arbitrary magnification according to the strength etc. which are required for textiles, it is preferred to consider it as the range of 0.7 to 2.5 times, and the range of 1.5 to 2.0 times. It is further preferred that When the draw ratio is less than 0.7 times, the process tension is lowered, and the mechanical properties of the fiber are lowered. On the other hand, when the draw ratio exceeds 2.5 times, the single yarn breaks at the time of drawing Increase, and fluff and process threading occur. In addition, the draw ratio here means the ratio of the fiber length after the process with respect to the fiber length before a extending | stretching process similarly to the said plastic stretching process demonstrated. That is, a draw ratio of 0.7 times means that the fibers are subjected to a contraction treatment to 70% of the original length in the dry heat treatment step, and a draw ratio of 1.0 times means a constant length heat treatment.

[The crimp process, etc.]
The black meta-type wholly aromatic polyamide fiber which has been subjected to the dry heat treatment may be further subjected to a crimping process, if necessary. Furthermore, after crimping, it may be cut into an appropriate fiber length and provided to the next step. Also, in some cases, it may be wound up as a multifilament yarn.

<Physical properties of black meta-type wholly aromatic polyamide fiber>
(Amount of residual solvent)
As described above, in the black meta-type wholly aromatic polyamide fiber of the present invention, the amount of the solvent remaining in the fiber is preferably 0.1% by weight or less, and more preferably 0.08% by weight. If the amount of residual solvent in the fiber exceeds 0.1% by weight, it volatilizes during processing and use under high temperature conditions, which is not preferable for safety.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples and the like.

<Measurement method>
Each physical property value in an Example and a comparative example was measured by the following methods.

[Fineness]
Based on JIS L 1015, the measurement based on the method A of regular fineness was carried out.

[Break strength / break elongation]
It measured on condition of the following using Instron company make and model number 5565 based on JISL1015.
(Measurement condition)
Measuring length: 20 mm
Initial load: 0.044 cN (1/20 g) / dtex
Tensile speed: 20 mm / min

[Remaining solvent in fiber]
About 1.0 mg of fiber was collected, and the amount of amide solvent remaining in the fiber was measured using gas chromatography (manufactured by Shimadzu Corporation, model: GC-2010). Subsequently, the concentration of the residual solvent in the fiber was calculated from a calibration curve prepared using an amide solvent as a standard sample.

Raw cotton color
The diffuse reflectance in a -10 degree field of view was measured using a light source D65, and the lightness index L * value and the chromaticness index a * and b * values were calculated by ordinary calculation processing.

[Heat storage ability]
It measured using illumination (IR100V / 125W) in atmosphere of 20 degreeC and 65% RH. The sample was stuck on a cardboard with a hole of 4 cm × 4 cm, and placed on a 1 cm thick acrylic plate having an opening of 15 cm × 15 cm. The distance between the illumination and the sample was 30 cm, and the temperature on the back of the sample was measured 15 minutes after the start of irradiation.

Example 1
[Polymerization process]
In a reaction vessel under a dry nitrogen atmosphere, 80.6 parts of N, N-dimethylacetamide (DMAc) having a water content of 100 ppm or less is weighed, and 9.5 parts of metaphenylene diamine is dissolved in this DMAc to obtain 0 ° C. It cooled. With respect to the cooled diamine solution, 17.7 parts of melted isophthalic acid chloride (hereinafter abbreviated as IPC) was added while being gradually stirred to carry out a polymerization reaction. Stirring was continued for 15 minutes after the viscosity change stopped.
Next, a dispersion prepared by uniformly dispersing 6.4 parts of calcium hydroxide powder having an average particle size of 20 μm or less in 12.1 parts of DMAc is slowly added to the polymer solution obtained by the polymerization reaction. A sum reaction was performed. After the calcium hydroxide addition was completed, the solution was stirred for 20 minutes to obtain a clear polymer solution.
It was 1.65 when polymetaphenylene isophthalamide was isolated from the obtained polymer solution, and intrinsic viscosity (I.V.) was measured.
A dispersion obtained by uniformly dispersing Lumogen Black made by BASF, which is a black pigment of infrared transmission type, uniformly in DMAc is added to the above polymer solution so that the pigment component becomes 3.0% by weight with respect to the polymer, and it is spun off under reduced pressure. A solution (spinning dope) was made.

[Spinning and coagulation process]
The obtained spinning solution was subjected to a yarn speed of 8.5 m / min in a coagulation bath having a coagulation bath temperature of 25 ° C. and a composition of water / DMAc = 45/55 from a spinneret with a pore diameter of 0.07 mm and a hole number of 1,500. And spinning.

[Plastic drawing process]
Subsequently, the film was stretched at a draw ratio of 3.7 times in a plastic stretching bath having a composition of water / DMAc = 45/55 at a temperature of 40.degree.

[Washing process]
After stretching, a 20 ° C. water / DMAc = 70/30 bath (immersion length 3.6 m), followed by a 20 ° C. water / DMAc = 50/50 bath (immersion length 3.6 m), a 30 ° C. water / Wash with DMAc = 30/70 bath (immersion length 3.6 m), 40 ° C. water bath (immersion length 3.6 m), and further warm water bath at 60 ° C. (immersion length 5.4 m), hot water bath at 80 ° C. It was thoroughly washed by passing through an immersion length of 7.2 m).

[Drying process]
After washing, it was wound and dried by a drying roller having a surface temperature of 150.degree.

[Dry heat treatment process]
After drying, the film was subjected to dry heat drawing 1.3 times with a heat plate having a surface temperature of 320 ° C., and then was subjected to dry heat treatment with a heat roller having a surface temperature of 320 ° C. to obtain black polymetaphenylene isophthalamide fiber. Physical properties of the obtained fiber are shown in Table 1. The fibers obtained were fibers having good non-heat storage properties.

Example 2
The same as in Example 1 except that Sumiplast Black HB manufactured by Sumika Chemtesk Co., Ltd., which is a black dye as an infrared transmitting dye, is added so that the pigment component is 3.2% by weight of the polymer in the spinning and coagulation process. As a result, a black meta-type wholly aromatic polyamide fiber was produced. Physical properties of the obtained fiber are shown in Table 1. The obtained fiber was a fiber having a good non-heat storage property as in Example 1.

Comparative Example 1
In the same manner as in Example 1 except that carbon black was used as a black dye and pigment in the spinning and coagulating step and the pigment component was added so as to be 2.5% by weight relative to the polymer, a black meta-type wholly aromatic polyamide fiber was prepared. Manufactured. Physical properties of the obtained fiber are shown in Table 1. The obtained fiber had a low transmittance in the infrared region, and was a fiber having a high heat storage property.

Comparative Example 2
In the spinning and coagulation process, except that Lumogen Black made by BASF and carbon black were used in combination as a black dye and pigment so as to be 1.5% by weight of Lumogen Black and 0.7% by weight of carbon black relative to the polymer In the same manner as in Example 1, a black meta-type wholly aromatic polyamide fiber was produced. Physical properties of the obtained fiber are shown in Table 1. The obtained fiber had a low transmittance in the infrared region as in Comparative Example 1, and was a fiber having a high heat storage property.

Claims (7)

The content of infrared ray transmitting type black dye and pigment is 0.2 to 10% by weight, the content of infrared ray impermeable type black dye and pigment is 0.1% by weight or less, and the following conditions are satisfied. Black meta-type wholly aromatic polyamide fiber characterized by
The average of the transmittance at a wavelength of 1,000 to 1,500 nm is 50% or more.
30% or more of the average of the transmittance | permeability in wavelength 1,500-2,000 nm.
The thermal storage property by the measuring method of the following description should be 50-53 degreeC.
Thermal storage
Under an atmosphere of 20 ° C and 65% RH, using lighting (IR 100 V / 125 W), the sample is a 4 cm × 4 cm hole in cardboard and used with the sample attached, and a 15 cm × 15 cm opening The sample was placed on a 1 cm thick acrylic plate, the distance between the illumination and the sample was 30 cm, and the temperature on the back of the sample was measured 15 minutes after the start of irradiation.   The black meta-type wholly aromatic polyamide fiber according to claim 1, wherein the infrared opaque black pigment is carbon black. The black meta-type wholly aromatic polyamide fiber according to claim 1 or 2, wherein the amount of residual solvent is 0.08 % by weight or less. A process for producing a black meta-type wholly aromatic polyamide fiber, comprising 0.2 to 10% by weight of an infrared ray transmitting black dye and 0.1% by weight or less of an infrared ray impermeable black dye or pigment And a heat treatment temperature in the dry heat treatment step after the drying step is in the range of 250 to 400 ° C. The method for producing a black meta-type wholly aromatic polyamide fiber according to claim 4, wherein the draw ratio of the fiber in the dry heat treatment step is in the range of 0.7 to 2.5 times. The manufacturing method of the black meta-type wholly aromatic polyamide fiber of Claim 4 or 5 whose heat storage property by the following description method is the range of 50-53 degreeC.
  Thermal storage
  Under an atmosphere of 20 ° C and 65% RH, using lighting (IR 100 V / 125 W), the sample is a 4 cm × 4 cm hole in cardboard and used with the sample attached, and a 15 cm × 15 cm opening The sample was placed on a 1 cm thick acrylic plate, the distance between the illumination and the sample was 30 cm, and the temperature on the back of the sample was measured 15 minutes after the start of irradiation. The average of the transmittance | permeability in wavelength 1,000-1,500 nm is 50% or more, The average of the transmittance | permeability in wavelength 1,500-2,000 nm is 30% or more. The manufacturing method of the black meta-type wholly aromatic polyamide fiber as described.