JP2013036132A - Method for dyeing aramid fiber base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for uniformly dyeing an aramid fiber base material, which imparts superior color fastness to the aramid fiber base material without using high-concentration of an acid aqueous solution and the like.SOLUTION: The method for dyeing the aramid fiber base material comprises: a first immersion process of immersing the aramid fiber base material into a surfactant aqueous solution containing 5 g/L or more of a nonionic surfactant and an anionic surfactant in total; and a second immersion process of immersing the aramid fiber base material after the first immersion process into a dye solution obtained by adding a cationic dye to an inorganic acid aqueous solution that contains an inorganic acid or a metal salt or ammonium salt of an inorganic acid and has a pH of 2-3. The method further comprises heating the aramid fiber base material in the second immersion process or after the second immersion process.

Description

  The present invention relates to a method for dyeing an aramid fiber substrate.

  Aramid fiber has excellent heat resistance, strength, and flame resistance, so it is used in a wide range of fields such as aircraft reinforcements, building materials, industrial materials, military equipment, sports equipment, racing equipment, safety clothing for firefighting, work gloves, etc. Has been. However, when dyeing aramid fibers, a method such as immersing the aramid fibers in a dye solution to which a surfactant is added, obtains high dyeability and dyeing fastness, and sufficiently suppresses the occurrence of uneven coloring. It was difficult.

  Therefore, as a method for dyeing such aramid fibers, a method is disclosed in which aramid fibers are brought into contact with an aqueous solution of sulfuric acid or chlorosulfuric acid before dyeing with a dye to sulfonate a part of the aramid fibers (patent). Reference 1).

Japanese Patent No. 2662201

  However, the method disclosed in Patent Document 1 requires a high-concentration acid aqueous solution of about 60 to 90% by weight, and has a problem in workability of the dyeing process.

  Therefore, the present invention can obtain an aramid fiber substrate that is sufficiently suppressed in color unevenness after dyeing and excellent in color fastness without using a high-concentration acid solution such as 60 to 90% by weight. It aims at providing the dyeing method of an aramid fiber base material.

  The present invention includes a first immersing step of immersing an aramid fiber substrate in an aqueous surfactant solution containing a total of 5 g / L or more of a nonionic surfactant and an anionic surfactant, and an inorganic acid or an inorganic acid metal A second immersing step of immersing the aramid fiber base material after the first immersing step in a dye solution obtained by adding a cationic dye to an aqueous inorganic acid solution having a pH of 2 to 3 containing a salt or an ammonium salt, and Provided is a method for dyeing an aramid fiber substrate, wherein the aramid fiber substrate is heated during the second immersion step or after the second immersion step. A plurality of inorganic acids may be used, and an inorganic acid and a metal salt or ammonium salt of the inorganic acid may be used in combination. In the latter case, the inorganic acid that forms a salt and the inorganic acid that does not form a salt may be the same or different.

  The dyed aramid fiber substrate obtained by the above dyeing method has little color unevenness, and is excellent in dyeing fastness and dyeability. In the present invention, after the aramid fiber substrate is immersed in the surfactant solution, the substrate is immersed in the dye solution, that is, the aramid fiber substrate is not immersed in the dye solution containing the surfactant. In addition, as a surfactant, not only an anionic surfactant but also a nonionic surfactant is used as part of the feature. With the configuration of the present invention including such features, the above-described effects can be achieved. In the method of the present invention, a nonionic surfactant is further contained as compared with the case where an aramid fiber substrate is immersed in a solution containing both an anionic surfactant and a cationic dye. It is assumed that the coagulation of the aramid fiber substrate can be effectively and uniformly adsorbed before the coagulation.

  In the dyeing method of the present invention, a total of 5 g / L or more of a nonionic surfactant and an anionic surfactant are contained. Thus, prior to dyeing, an aramid fiber substrate is contained in a high-concentration surfactant aqueous solution. By soaking, it becomes possible to improve the dyeability of the aramid fiber substrate. In the present invention, it is preferable to heat the aramid fiber substrate during the second immersion step, and in particular, the aramid fiber substrate after the first immersion step at less than 70 ° C. in the second immersion step. It is preferable to heat the said aramid fiber base material to 70 degreeC or more, after being immersed in, after being immersed.

  The aramid fiber substrate is preferably a meta-aramid fiber substrate. When the aramid fiber substrate is a meta-aramid fiber substrate, the color unevenness after dyeing is more remarkably reduced, and an aramid fiber substrate with better dyeing fastness can be obtained.

  The mass ratio of the nonionic surfactant to the anionic surfactant (nonionic surfactant / anionic surfactant) in the aqueous surfactant solution is preferably 30/1 to 3/1. The dyed aramid fiber base material obtained by such a dyeing method is further reduced in color unevenness and dirt, and further improves dyeability and dyeing fastness.

  This is because nonionic surfactants tend to have low solubility in water, and when there are many anionic surfactants, the cationic dye adheres only to the surface of the fiber bundle of aramid fibers, This is thought to be due to the tendency to penetrate into the interior and not adhere to the internal fibers.

  The nonionic surfactant is preferably a polyoxyalkylene alkyl ether or a polyoxyalkylene phenyl ether.

  Nitric acid and sulfuric acid are preferably used in combination as the inorganic acid.

  According to the present invention, it is possible to provide a method for dyeing an aramid fiber base material that suppresses color unevenness and is excellent in dyeing fastness without using a high-concentration acid aqueous solution or the like. In the dyeing method of the present invention, since the pH of the dye solution may be 2 to 3, an acid solution having a lower concentration than 60 g / L may be used.

  The dyeing | staining method of this invention includes a 1st immersion process and a 2nd immersion process, and heats during a 2nd immersion process or after a 2nd immersion process. Hereinafter, embodiments of the staining method of the present invention will be described step by step.

  In the first immersing step, the aramid fiber substrate is immersed in a surfactant aqueous solution containing a total of 5 g / L or more of a nonionic surfactant and an anionic surfactant. Here, the aramid fiber substrate means a substrate made of aramid fibers. Although an aramid fiber base material is divided roughly into a meta-type aramid fiber base material and a para-type aramid fiber base material, it is preferable that it is a meta-type aramid fiber base material. When the aramid fiber base material is a meta-type aramid fiber base material, color unevenness of the dyed aramid fiber base material is further suppressed, and the dyeability and dyeing fastness tend to be further improved.

  Nonionic surfactants contained in the aqueous surfactant solution can be broadly classified into, for example, polyethylene glycol type and polyhydric alcohol type. Examples of the former include higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene. Examples thereof include oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts, fat and oil ethylene oxide adducts, and polypropylene glycol ethylene oxide adducts. Examples of the latter include fatty acid esters of glycerol, fatty acid esters of pentaerythritol, fatty acid esters of sorbitol and sorbitan, fatty acid esters of sucrose, ethers of polyhydric alcohols, fatty acid amides of alkanolamines, and the like. The nonionic surfactant is preferably a polyoxyalkylene alkyl ether or a polyoxyalkylene phenyl ether.

  Examples of the anionic surfactant contained in the aqueous surfactant solution include soaps that are carboxylates, higher alcohol sulfates, higher alkyl ether sulfates, sulfated oils, sulfated fatty acid esters, sulfated olefins, Examples thereof include alkylbenzene sulfonate, alkyl naphthalene sulfonate, paraffin sulfonate, Ikepon T (trade name), aerosol OT (trade name), and higher alcohol phosphate ester salts. The anionic surfactant is preferably compatible with the nonionic surfactant. Compatibility can be determined by whether or not turbidity or precipitation occurs when an anionic surfactant and a nonionic surfactant are mixed in water. If such a phenomenon does not occur, it is determined that the compatibility is good. it can.

  The total concentration of the nonionic surfactant and the anionic surfactant in the aqueous surfactant solution is 5 g / L or more. When the concentration of the surfactant in the aqueous surfactant solution is 5 g / L or more, an aramid fiber substrate having excellent dyeability can be obtained. However, if the concentration of the surfactant in the surfactant aqueous solution is excessively high, there will be no problem with dyeing, but the dyeing cost will increase due to the increased cleaning effort and the amount of surfactant used after dyeing. Tend to. Therefore, the upper limit of the total concentration of the nonionic surfactant and the anionic surfactant is preferably 50 g / L. A more preferable range of the total concentration is 10 to 50 g / L.

  About mass ratio of nonionic surfactant and anionic surfactant in surfactant aqueous solution, nonionic surfactant / anionic surfactant = 30 / 1-3 / 1 is preferable. The nonionic surfactant / anionic surfactant is more preferably 30/1 to 5/1, further preferably 20/1 to 8/1, and particularly preferably 15/1 to 10/1.

  When the aqueous surfactant solution contains a nonionic surfactant having a mass ratio of 30/1 or less between the nonionic surfactant and the anionic surfactant, it further suppresses the occurrence of color unevenness and stains in the dyeing of the aramid fiber substrate. Tend to be able to. Further, the aqueous surfactant solution contains a nonionic surfactant having a mass ratio of 3/1 or more of the nonionic surfactant and the anionic surfactant, thereby further improving the dyeability and dyeing fastness of the aramid fiber substrate. Tend to be able to.

  The temperature of the aqueous surfactant solution when the aramid fiber substrate is immersed in the aqueous surfactant solution is preferably 20 to 70 ° C. The immersion time of the aramid fiber base material in the surfactant aqueous solution is preferably 1 minute or longer, and more preferably 2 minutes to 5 minutes. When the immersion temperature is 20 ° C. or higher and the immersion time is 1 minute or longer, there is a tendency that a colored aramid fiber base material that is more suppressed in color unevenness and excellent in dyeing fastness can be obtained.

  In the second immersion step, in a dye solution in which a cationic dye is added to an inorganic acid aqueous solution having a pH of 2 to 3 containing an inorganic acid, or a metal salt or ammonium salt of an inorganic acid (hereinafter sometimes referred to as “inorganic acids”). The aramid fiber base material after the first immersion step is immersed. Here, the cationic dye is also known as a basic dye, and typically contains a basic group such as an amino group or a substituted amino group, and the pigment portion generates a cation. Examples of the cationic dye include insulating cationic dyes and conjugated cationic dyes. The cationic dye is preferably a dye capable of dyeing an aramid fiber base material in a dark color such as black, amber, vermilion, or blue.

  The dye solution can be obtained by adding the above-described cationic dye to an aqueous solution of inorganic acids. The dye solution may contain at least one inorganic acid and may be used in combination of two or more. Examples of inorganic acids include hydrochloric acid, sulfuric acid, and nitric acid. Examples of the inorganic acid metal salts include sodium salts and calcium salts of inorganic acids. The inorganic acid or its metal salt or ammonium salt is selected from the group consisting of at least one selected from the group consisting of nitric acid, nitric acid metal salt and nitric acid ammonium salt, and the group consisting of sulfuric acid, sulfuric acid metal salt and sulfuric acid ammonium salt. It is preferable that the compound contains at least one selected from the above (that is, nitric acid and sulfuric acid are used in combination as inorganic acids). The concentration of the inorganic acids in the aqueous inorganic acid solution is preferably 2 to 50 g / L, more preferably 3 to 30 g / L. Since such an inorganic acid aqueous solution has a low concentration, a safer dyeing operation is possible.

  The pH of the inorganic acid aqueous solution is 2-3. The pH of the inorganic acid aqueous solution can be adjusted with formic acid, acetic acid or the like as necessary so that the pH is 2 to 3. The addition amount of the cationic dye to the inorganic acid aqueous solution may be appropriately selected depending on the kind of the cationic dye, but is preferably 0.01 to 3.0 parts by mass with respect to 100 parts by mass of the inorganic acid aqueous solution. It is more preferably 1 to 2.0 parts by mass.

  It is preferable that the temperature of the dye solution when the aramid fiber substrate after the first immersion step is immersed in the dye solution is 20 to 65 ° C. The immersion time of the aramid fiber substrate in the dye solution is preferably 3 minutes or longer (more preferably 3 minutes to 60 minutes). In addition, the aramid fiber base material may be immersed in the surfactant aqueous solution in the first immersion step, and then squeezed and immersed in a dye solution in another bathtub, or the surfactant in the first immersion step. After being immersed in the aqueous solution, it may be immersed in the dye solution as a mixed solution in which the dye solution is added to the same bath as the surfactant aqueous solution.

  When the aramid fiber substrate is immersed in a surfactant aqueous solution and then squeezed and immersed in a dye solution in another bathtub, the aramid fiber substrate is squeezed and then immersed in the dye solution. It may be dried and immersed in the dye solution, but may be directly immersed in the dye solution without drying.

  Heating is performed on the aramid fiber substrate during the second immersion step or the aramid fiber substrate after the second immersion step (heating step). The heating temperature is preferably 70 ° C. or higher, more preferably 70 to 160 ° C., and further preferably 80 to 150 ° C. The heating time is preferably 30 to 150 minutes. The heat treatment may be, for example, heating the dye solution in which the aramid fiber base is immersed at 70 ° C. or higher under normal pressure or pressure, or removing the aramid fiber base from the dye solution and applying normal pressure or pressure. Heating at 70 ° C. or higher under pressure (preferably, heating at 100 to 160 ° C. with steam (steaming treatment)) may be used. By heating the aramid fiber substrate, characteristics such as dyeability and dyeing fastness of the aramid fiber substrate are improved. When heating the aramid fiber substrate during the second dipping step, the dye solution in the second dipping step is set to a temperature suitable for heating the aramid fiber substrate from the beginning (for example, the above heating temperature), and dyeing is performed. And heating may be performed simultaneously. However, characteristics such as dyeability and dyeing fastness are improved when the aramid fiber substrate is taken out from the dye solution and heated under normal pressure or pressure (for example, the above heating temperature) rather than this method. From the viewpoint of further improving these characteristics, it is preferable to change the temperature to a temperature suitable for heating the aramid fiber substrate (for example, the above heating temperature) from the middle of the second immersion step. In this case, in the second immersion step, after the aramid fiber base material after the first immersion step is immersed in the dye solution at a temperature lower than 70 ° C. (for the temperature, preferably 20 ° C. or higher and lower than 70 ° C., further 20 ° C. More than 65 ° C. The time is preferably 3 minutes or more, more preferably 3 minutes or more and 60 minutes or less, and the aramid fiber substrate is heated to 70 ° C. or more while being immersed (the temperature is preferably 70). It is particularly preferable that the temperature is from 160 ° C. to 160 ° C., more preferably from 80 ° C. to 150 ° C. The time is preferably 30 to 150 minutes.

  The dyed aramid fiber substrate can be obtained through the heating step and dried. If necessary, the dyed aramid fiber base material may be soaped with a 45% by weight naphthalenesulfonic acid soda formalin aqueous solution or the like before or after drying. Examples of the base material of the aramid fiber base material include yarn, raw cotton, fabric (woven fabric, knitted fabric), and non-woven fabric.

Example 1
A surfactant aqueous solution containing 13 g / L of polyoxyethylene chlorophenyl ether as a nonionic surfactant and 1 g / L of alkylbenzene sulfonic acid soda as an anionic surfactant was obtained. That is, a surfactant aqueous solution containing a nonionic surfactant and an anionic surfactant at a concentration of 14 g / L and having a mass ratio of nonionic surfactant to anionic surfactant of 13/1 was obtained.

  On the other hand, ammonium sulfate, sodium nitrate and acetic acid were dissolved in water to obtain an aqueous inorganic acid solution having concentrations of ammonium sulfate 5 g / L, sodium nitrate 5 g / L and acetic acid about 5 g / L. 1.0 part by mass of a cationic dye (Basic Dyes Blue 54) was added to 100 parts by mass of the aqueous inorganic acid solution to obtain a dye solution having a pH of 2.5.

An aramid fiber base material (a plain weave fabric with a mass of 320 g / m ² ) was dipped in the surfactant aqueous solution at 30 ° C. for 3 minutes, and the surfactant aqueous solution was stirred. The aramid fiber substrate after stirring was transferred to the dye solution and immersed in the dye solution at 30 ° C. for 5 minutes to stir the dye solution. Thereafter, the dye solution in which the aramid fiber substrate was immersed was heated at 140 ° C. for 90 minutes.

  The obtained aramid fiber substrate is taken out from the dye solution, washed with a 2 g / L aqueous solution of sodium naphthalene sulfonate formalin condensate, dried by heating at 80 ° C. for 20 minutes, and a dyed aramid fiber substrate is obtained. Obtained.

(Example 2)
Example 1 except that a surfactant aqueous solution containing 10 g / L of polyoxyethylene chlorophenyl ether as a nonionic surfactant and 3 g / L of alkylbenzene sulfonic acid soda as an anionic surfactant was used as the surfactant aqueous solution. A dyed aramid fiber substrate was obtained. The surfactant aqueous solution contained a nonionic surfactant and an anionic surfactant at a concentration of 13 g / L, and the mass ratio of the nonionic surfactant to the anionic surfactant was 10/3.

(Comparative Example 1)
A dyed aramid fiber substrate was obtained in the same manner as in Example 1 except that an inorganic acid aqueous solution having a pH of 4.0 consisting of only about 0.1 g / L of acetic acid was used.

(Comparative Example 2)
Example 1 except that a surfactant aqueous solution containing 3 g / L of polyoxyethylene chlorophenyl ether as a nonionic surfactant and 0.2 g / L of alkylbenzene sulfonic acid soda as an anionic surfactant was used as the surfactant aqueous solution. A dyed aramid fiber substrate was obtained in the same manner as described above. The surfactant aqueous solution contained a nonionic surfactant and an anionic surfactant at a concentration of 3.2 g / L, and the mass ratio of the nonionic surfactant to the anionic surfactant was 3 / 0.2.

(Comparative Example 3)
Aramid dyed in the same manner as in Example 1 except that a surfactant aqueous solution containing 15 g / L of polyoxyethylene chlorophenyl ether as a nonionic surfactant and not containing an anionic surfactant was used. A fiber substrate was obtained. The surfactant aqueous solution contained only a nonionic surfactant at a concentration of 15 g / L, and the mass ratio of the nonionic surfactant to the anionic surfactant was 15/0.

(Comparative Example 4)
The aramid fiber substrate was immersed in a mixed solution obtained by mixing the same aqueous surfactant solution and dye solution as the surfactant aqueous solution and dye solution used in Example 1, and the mixed solution was stirred at 30 ° C. for 10 minutes. Thereafter, the mixed solution in which the aramid fiber base material was immersed was heated at 140 ° C. for 90 minutes. Next, an aramid fiber substrate dyed by washing and drying as in Example 1 was obtained.

<Color unevenness, dirt>
The color irregularities and stains of the dyed aramid fiber base materials obtained in Examples 1 and 2 and Comparative Examples 1 to 4 were visually evaluated according to the following criteria. The evaluation results are shown in Table 1.
A: No color unevenness / stain B: Some color unevenness / stain C: Color unevenness / stain is noticeable

<Sweat fastness>
An evaluation test of sweat fastness of the dyed aramid fiber base materials obtained in Examples 1-2 and Comparative Examples 1-4 was conducted according to JIS L0848 (Test method for fastness to dyeing sweat) and evaluated according to the following criteria. . The evaluation results are shown in Table 1.
A: Grade 5 to Grade 4 B: Grade 3-4 to Grade 2-3 C: Grade 2 to Grade 1

<Friction fastness>
The evaluation test of the friction fastness of the dyed aramid fiber base materials obtained in Examples 1-2 and Comparative Examples 1-4 was subjected to a drying test according to JIS L0849 (Dye Fastness Test Method for Friction), and the following criteria It was evaluated with. The evaluation results are shown in Table 1.
A: Grade 5 to Grade 4 B: Grade 3-4 to Grade 2-3 C: Grade 2 to Grade 1

Claims (5)

A first immersing step of immersing the aramid fiber substrate in an aqueous surfactant solution containing a total of 5 g / L or more of a nonionic surfactant and an anionic surfactant;
Second dipping in which the aramid fiber substrate after the first dipping step is dipped in a dye solution obtained by adding a cationic dye to an inorganic acid aqueous solution having a pH of 2 to 3 containing an inorganic acid or a metal salt or ammonium salt of an inorganic acid A process, and
A method for dyeing an aramid fiber substrate, wherein the aramid fiber substrate is heated during the second immersion step or after the second immersion step.   The dyeing method according to claim 1, wherein the aramid fiber substrate is a meta-aramid fiber substrate.   The mass ratio of the nonionic surfactant to the anionic surfactant (nonionic surfactant / anionic surfactant) in the aqueous surfactant solution is 30/1 to 3/1. The dyeing | staining method as described.   The dyeing method according to any one of claims 1 to 3, wherein the nonionic surfactant is a polyoxyalkylene alkyl ether or a polyoxyalkylene phenyl ether.   The dyeing | staining method as described in any one of Claims 1-4 which uses nitric acid and a sulfuric acid together as the said inorganic acid.