JP2016199815A - Black color meta type all aromatic polyamide fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a black color meta type all aromatic polyamide fiber small in temperature rising by radiation of infrared ray and having suppressed heat absorption.SOLUTION: There is provided a black color meta type all aromatic polyamide fiber having the content of an infrared ray transmission type black color dye pigment of 0.2 to 10 wt.%, the content of an infrared ray non-transmission type black color dye pigment of 0.1 wt.% or less, the average of transmission coefficients at wavelength of 1,000 to 1,500 nm of 50% or more and the average of transmission coefficients at wavelength of 1,500 to 2,000 nm of 30% or more.SELECTED DRAWING: None

Description

  The present invention relates to a black meta-type wholly aromatic polyamide fiber using an infrared transmission type black dye / pigment.

The meta-type wholly aromatic polyamide typified by polymetaphenylene isophthalamide (hereinafter sometimes abbreviated as "meta-aramid") has excellent heat resistance because most of its molecular skeleton is composed of aromatic rings. It has properties such as flame retardancy and dimensional stability. Taking advantage of these characteristics, meta-aramid fibers are suitably used for industrial applications and protective clothing applications.
Among them, the original meta-aramid fiber using a black pigment is widely used as protective clothing in fire fighting, military, manufacturing sites and the like because it has good light fastness and deep color development.
However, since the black original meta-aramid fiber is generally colored with a pigment mainly composed of carbon black, the temperature of clothes significantly increases due to the absorption of infrared rays in a working environment that receives radiant heat from sunlight or flame. , Had the problem of hindering the activities of firefighters and workers.

JP 2006-241640 A

  This invention is made | formed in view of the said background art, The place made into the objective is providing the black meta type wholly aromatic polyamide fiber which suppressed heat absorption.

  This inventor repeated earnest research in view of said subject. As a result, a specific amount of the infrared transmissive black dye / pigment is blended, the blend amount of the infrared opaque black pigment / pigment is set to a specific amount or less, and the transmittance in the infrared region with a wavelength of 1000 to 2000 nm is within a specific range. The present inventors have found that the above problems can be solved, and have completed the present invention.

  That is, according to the present invention, the content of the infrared transmitting black dye / pigment is 0.2 to 10% by weight, the content of the infrared opaque black dye / pigment is 0.1% by weight or less, and the wavelength 1 The black meta-type wholly aromatic polyamide fiber has an average transmittance of 50% or more at 1,000 to 1,500 nm and an average transmittance of 30% or more at a wavelength of 1,500 to 2,000 nm.

The black meta-type wholly aromatic polyamide fiber of the present invention is colored with an infrared transmission type black dye / pigment, so that the temperature rise due to infrared radiation is small. That is, in addition to the inherent properties of meta-type wholly aromatic polyamide fibers such as flame retardancy and heat resistance, the product can be lifted even when receiving radiation including infrared rays from various heat sources such as sunlight and flame. Temperature can be suppressed.
Therefore, since the clothing made using the black meta-type wholly aromatic polyamide fiber of the present invention exhibits excellent non-heat storage in a work environment that receives heat radiation, protective clothing such as fire-fighting clothing and heat-resistant work clothing Can be suitably used.

<Configuration 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. For example, other copolymer components such as the para type may be copolymerized within a range not inhibiting.
Particularly preferred for use in the present invention is a meta-type wholly aromatic polyamide having a metaphenylene isophthalamide unit as a main component from the viewpoints of mechanical properties and heat resistance. As the meta-type wholly aromatic polyamide composed of metaphenylene isophthalamide units, the metaphenylene isophthalamide units are preferably 90 mol% or more of the total repeating units, more preferably 95 mol% or more, particularly preferably. 100 mol%.

<Method for producing meta-type wholly aromatic polyamide>
The production method of 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, the meta-type aromatic diamine component and the meta-type aromatic dicarboxylic acid chloride component Can be produced by solution polymerization, interfacial polymerization or the like.
The molecular weight of the meta-type wholly aromatic polyamide is not particularly limited as long as it can form fibers. In general, in order to obtain a fiber having sufficient physical properties, a polymer having an intrinsic viscosity (IV) measured in a concentrated sulfuric acid at 30 ° C. with a polymer concentration of 100 mg / 100 mL sulfuric acid is in a range of 1.0 to 3.0. Appropriate 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 uses, for example, the spinning solution preparation process, spinning / coagulation process, plastic drawing described below, using the meta-type wholly aromatic polyamide obtained by the above-described production method and the like. It can be manufactured through a process, a cleaning process, a drying process, and a dry heat treatment process.

[Spinning liquid preparation process]
In the spinning solution preparation step, the meta-type wholly aromatic polyamide is dissolved in an amide solvent, and a dye / pigment necessary for obtaining the black meta-type wholly aromatic polyamide of the present invention is added to the spinning solution (meta-type). The total aromatic polyamide polymer solution). In adjusting the spinning solution, an amide solvent is usually used, and examples of the amide solvent used include N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), and dimethylacetamide (DMAc). . Of these, NMP or DMAc is preferably used from the viewpoints of solubility and handling safety.
The solution concentration may be appropriately selected from the viewpoints of spinnability and polymer solubility in the next spinning / coagulation step. For example, the polymer is polymetaphenylene isophthalamide and the solvent is NMP. In the case of, it is usually preferred to be in the range of 10 to 30% by mass.

(Dye and pigment)
In the present invention, an infrared transmissive black dye / pigment is used. The dyes and pigments may be used singly or in combination of two or more. The combination of dyes and pigments in the case of using two or more of them 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 solvent slurry in which the dye / pigment is uniformly dispersed in an amide solvent is prepared, and the amide solvent slurry is used. Examples thereof include a method of adding a meta type wholly aromatic polyamide to a solution in which the amide type solvent is dissolved, or a method of directly adding a dye / pigment powder to a solution in which the meta type wholly aromatic polyamide is dissolved in an amide solvent.

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

(Infrared opaque black dye / pigment)
The black meta-type wholly aromatic polyamide fiber of the present invention may contain an infrared-opaque black dye / pigment other than the above-mentioned infrared-transmissive black dye / pigment. The infrared-opaque black dye / pigment is preferably carbon black, and its blending amount is essential to be 0.1% by weight or less with respect to the black meta-type wholly aromatic polyamide fiber. In the case of 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 / coagulation step, the spinning solution (meta-type wholly aromatic polyamide polymer solution) prepared above is spun into a coagulation solution and coagulated, that is, a coagulated yarn is formed by a wet spinning method. In the spinneret used, the number of spinning holes, the arrangement state, the hole shape and the like do not need to be particularly limited, but from the viewpoint of productivity and spinnability, the number of holes is 10,000 to 30,000, and the spinning hole diameter is 0.04. It is preferable to use a multi-hole spinneret with a thickness of ˜0.7 mm. The temperature of the polymer solution when spinning from the spinneret is suitably in the range of 25 to 40 ° C.

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

  In order to obtain a porous fibrous material having a homogeneous structure, it is important to set the composition and temperature of the coagulation liquid used in the coagulation bath to specific conditions. The coagulation liquid is substantially composed of an amide solvent and water. It is preferable to make it the aqueous solution which consists of two components. However, when inorganic salts such as calcium chloride and calcium hydroxide are contained in the polymer solution, they are extracted into the coagulating liquid, so that the coagulating liquid actually contains a small amount of these salts. A suitable concentration of the salt in industrial implementation is in the range of 0.3% by mass to 10% by mass with respect to the entire coagulation liquid. In order to make the inorganic salt concentration less than 0.3% by mass, the recovery cost for purification in the recovery process of the coagulating liquid becomes remarkably high, which is not appropriate. On the other hand, when the inorganic salt concentration exceeds 10% by mass, the coagulation rate is slow, so that the fibers before being porous immediately after being discharged from the spinneret are likely to be fused, Since the coagulation time becomes long, the coagulation equipment must be enlarged, which is not preferable.

As the amide solvent used in the coagulation liquid, any solvent can be used as long as it dissolves the meta-type wholly aromatic polyamide polymer and mixes well with water. Particularly, N-methyl-2-pyrrolidone (NMP), Dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylimidazolidinone and the like can be suitably used.
The concentration of the amide solvent in the coagulation liquid (hereinafter referred to as coagulation liquid concentration) is a condition that greatly affects the porous structure of the coagulated yarn. In particular, the concentration of the coagulating liquid that comes into contact with the polymer solution immediately after being discharged from the die has a great influence on the porous structure and fiber quality, and must be strictly controlled. For this reason, the concentration of the coagulating liquid in the vicinity of the die needs to be set to an appropriate concentration at which the target fiber structure can be obtained according to the polymer solution concentration and the degree of polymer polymerization.

In order to obtain a homogeneous porous structure without spots, it is preferable to set the central value of the coagulating liquid concentration within the range of 45.0 to 60.0%. Under conditions below this range, very large voids are likely to occur in the coagulated fiber, which tends to cause subsequent single yarn breakage. In addition, a structure having a thick skin is formed, the cleaning efficiency in the cleaning step is lowered, and it is difficult to make the residual solvent amount of the obtained fiber 0.1% by weight or less. On the other hand, solidification does not proceed under conditions exceeding this range, and fiber fusion tends to occur.
Further, the temperature of the coagulation bath has a close relationship with the composition of the coagulation solution, and it is necessary to strictly control it similarly to the amide solvent concentration. The concentration of the coagulation liquid depends on the coagulation time, but the center value is preferably in the range of 10 to 35 ° C.

[Plastic stretching process]
In the plastic drawing step, the fiber bundle made of the porous coagulated yarn obtained in the coagulation step is drawn in air or in a bath. In the present invention, the film is preferably stretched at a stretch ratio of 3.5 to 5.0 times. The draw ratio here means the ratio of the fiber length after treatment to the fiber length before stretch treatment. By stretching at a high magnification, the micropores of the porous coagulated yarn are crushed, the densification in the heat treatment process described later proceeds well, and the mechanical properties such as strength and elastic modulus of the resulting fiber are improved. be able to. In addition, when stretching is performed at an extremely high magnification, single yarn breakage tends to occur during stretching, 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. Since washing affects the quality of the fibers obtained, it is preferable to carry out washing in a multistage washing bath. In particular, the temperature of the cleaning liquid in the cleaning step and the concentration of the amide solvent in the cleaning liquid affect the extraction state of the amide solvent from the fiber and the infiltration state of water from the cleaning bath into the fiber. 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 for the purpose of bringing them into an optimum state.
The temperature condition and the concentration condition of the amide solvent are not particularly limited as long as the quality of the finally obtained fiber can be satisfied, but if the initial washing bath is at a high temperature of 60 ° C. or higher, water Since the intrusion into the fiber rapidly occurs, a huge void is generated in the fiber, resulting in deterioration of quality. For this reason, it is preferable that the first washing bath be 30 ° C. or lower. Subsequently, it is preferable to wash with hot water of 50 to 90 ° C.

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

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

  The draw ratio in the dry heat treatment step is closely related to the expression of the strength of the obtained fiber. The draw ratio can be selected arbitrarily depending on the strength required of the fiber, but is preferably in the range of 0.7 to 2.5 times, in the range of 1.5 to 2.0 times More preferably. When the draw ratio is less than 0.7 times, the mechanical tension of the fiber is lowered because the process tension is lowered. On the other hand, when the draw ratio is more than 2.5 times, the single yarn breaks during drawing. Increases, and fluff and process breakage occur. The stretch ratio here means the ratio of the fiber length after the treatment to the fiber length before the stretch treatment, as described in the plastic stretching step. That is, a draw ratio of 0.7 times means that the fiber is subjected to a limit shrinkage treatment to 70% of the original length by a dry heat treatment step, and a draw ratio of 1.0 times means a constant length heat treatment.

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

<Physical properties of black meta-type wholly aromatic polyamide fiber>
(Residual solvent amount)
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, although an Example is given and this invention is demonstrated concretely, this invention is not limited by these Examples.

<Measurement method>
Each physical property value in Examples and Comparative Examples was measured by the following method.

[Fineness]
Based on JIS L 1015, the measurement based on the A method of positive fineness was implemented.

[Breaking strength / breaking elongation]
Based on JIS L1015, it measured on condition of the following using the model number 5565 by Instron.
(Measurement condition)
Measurement length: 20mm
Initial load: 0.044 cN (1/20 g) / dtex
Tensile speed: 20 mm / min

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

[Raw cotton hue]
The diffuse reflectance in a -10 degree visual field was measured using the light source D65, and the lightness index L * value, the chromaticness index a *, and the b * value were calculated by a normal calculation process.

[Heat storage]
It measured using illumination (IR100V / 125W) in 20 degreeC and 65% RH atmosphere. The sample was affixed with 4 cm × 4 cm holes on cardboard 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 of the back surface of the sample 15 minutes after the start of irradiation was measured.

<Example 1>
[Polymerization process]
In a reaction vessel under a dry nitrogen atmosphere, 80.6 parts of N, N-dimethylacetamide (DMAc) having a moisture content of 100 ppm or less is weighed, and 9.5 parts of metaphenylenediamine is dissolved in this DMAc to reach 0 ° C. Cooled down. To this cooled diamine solution, 17.7 parts of molten isophthalic acid chloride (hereinafter abbreviated as IPC) was added while gradually stirring to carry out a polymerization reaction. Stirring was continued for 15 minutes after the change in viscosity stopped.
Next, a dispersion obtained 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 addition of calcium hydroxide was completed, the mixture was stirred for 20 minutes to obtain a transparent polymer solution.
When polymetaphenylene isophthalamide was isolated from the obtained polymer solution and the intrinsic viscosity (IV) was measured, it was 1.65.
To the above polymer solution, a dispersion obtained by uniformly dispersing BASF's Lumogen Black, which is an infrared transmitting black pigment, in DMAc is added so that the pigment component is 3.0% by weight of the polymer, and depressurization is performed for spinning. A solution (spinning dope) was prepared.

[Spinning and coagulation process]
The obtained spinning solution was put into a coagulation bath having a composition of water / DMAc = 45/55 from a spinneret having a pore diameter of 0.07 mm and a number of holes of 1,5000, and a yarn speed of 8.5 m / min. And then spun and spun.

[Plastic stretching process]
Subsequently, the film was stretched 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.

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

[Drying process]
After washing, the film was dried by winding with a drying roller having a surface temperature of 150 ° C.

[Dry heat treatment process]
After drying, the film was subjected to dry heat stretching 1.3 times with a hot plate having a surface temperature of 320 ° C., followed by dry heat treatment with a hot roller having a surface temperature of 320 ° C. to obtain black polymetaphenylene isophthalamide fibers. Table 1 shows the physical properties of the obtained fiber. The obtained fiber was a fiber having a good non-heat storage property.

<Example 2>
In the spinning / coagulation step, the same as Example 1 except that Sumiplast Black HB manufactured by Sumika Chemtesque Co., Ltd., which is a black dye as an infrared transmitting dye pigment, was added so that the pigment component was 3.2% by weight relative to the polymer. Thus, a black meta type wholly aromatic polyamide fiber was produced. Table 1 shows the physical properties of the obtained fiber. The obtained fiber was a fiber having a good non-heat storage property as in Example 1.

<Comparative Example 1>
In the spinning / coagulation step, black meta-type wholly aromatic polyamide fiber was used in the same manner as in Example 1 except that carbon black was used as the black dyeing pigment and the pigment component was added so as to be 2.5% by weight of the polymer. Manufactured. Table 1 shows the physical properties of the obtained fiber. The obtained fiber was a fiber having a low transmittance in the infrared region and a high heat storage property.

<Comparative example 2>
In the spinning and coagulation process, except that BASF's Lumogen Black and carbon black are used in combination as a black dye / pigment, and the polymer is compared so that Lumogen Black is 1.5% by weight and carbon black is 0.7% by weight. Produced a black meta-type wholly aromatic polyamide fiber in the same manner as in Example 1. Table 1 shows the physical properties of the obtained fiber. The obtained fiber had a low transmittance in the infrared region as in Comparative Example 1, and was a highly heat-storing fiber.

Claims (3)

  The content of the infrared transmitting black dye / pigment is 0.2 to 10% by weight, the content of the infrared opaque black dye / pigment is 0.1% by weight or less, and the wavelength is 1,000 to 1,500 nm. A black meta-type wholly aromatic polyamide fiber having an average transmittance of 50% or more and a transmittance of 30% or more at a wavelength of 1,500 to 2,000 nm.   The black meta-type wholly aromatic polyamide fiber according to claim 1, wherein the infrared-opaque black dye / pigment is carbon black.   The black meta type wholly aromatic polyamide fiber according to claim 1 or 2, wherein the residual solvent amount is 0.1% by weight or less.