JP2009256844A - Method for dyeing p-aramid fiber, and textile fiber structural product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for dyeing p-aramid fibers in high clearness and high color fastness to light, and to provide a fabric containing the thus dyed p-aramid fibers. <P>SOLUTION: The method for dyeing p-aramid fibers includes the following steps: Para-aramid fibers imparted with kinkbands are dyed in a pH2-5.5 aqueous solution using a cationic dye in the presence of an alkali metal salt and/or an alkaline earth metal salt and a carrier having the effect of fiber structure relaxation or dropping of apparent glass transition point. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to work clothes, gloves, socks, protective clothing such as fire-fighting and fire-prevention clothing, furnace clothing, sports clothing used for skiing, snowboarding, mountain climbing, motor sports, etc., work uniforms such as buildings and factories, theaters, movies High-definition and light-resistant dyeing method and dyed para-aramid fiber (hereinafter abbreviated as aramid fiber) that can be used for interior seats, bedding, etc. for seats, curtains, sheets, etc. The present invention relates to a fabric containing an aramid fiber.

Aramid fibers include meta-aramid fibers represented by Conex and Nomex, and para-aramid fibers represented by Technora, Kevlar and Twaron.
These aramid fibers are heat resistant and flame resistant (flame retardant) due to their rigid molecular structure and high crystallinity compared to the widely used aliphatic polyamide fibers such as nylon 6 and nylon 66. As well as excellent thermal properties such as chemical resistance, strong radiation resistance, and electrical properties. Therefore, it is widely used for clothing such as protective clothing that requires flame resistance (flame resistance) and heat resistance, industrial materials such as bag filters, and interiors such as curtains.

However, since the aramid fiber has a rigid molecular chain and high crystallinity, it has the disadvantage that it is difficult to post-process dyeing.
In particular, it is very difficult to dye para-aramid fibers that are mixed uniformly and quantitatively, and when a fiber structure containing para-aramid fibers is dyed, only the mixed para-aramid fibers are not dyed and the irritations are conspicuous and of high quality. It has a problem that it is difficult to finish.

  JP-A-8-260362 discloses a method for dyeing para-aramid fibers at 130 ° C. or higher while keeping an aqueous dispersion of an aromatic ether fiber swelling agent and a cationic dye at pH 5 or lower. Although there was a clear dyeing, there was a problem that the light fastness was poor.

  Japanese Patent Application Laid-Open No. 2005-325471 discloses a method of dyeing with an acid dye in the presence of a specific Bola electrolyte compound. Although the dyeability was good, there was a problem that the fastness to washing and the fastness to friction were not good.

  Furthermore, Japanese Patent Application Laid-Open No. 2007-16343 proposes dyeing a para-aramid fiber having a buckled portion with a cation or a disperse dye. However, there is a problem that the dyeing stability is improved but the dyeing stability is poor.

JP-A-8-260362 JP 2005-325471 A JP 2007-16343 A

  An object of the present invention is to provide a method for dyeing para-aramid fibers that are clear and have high light resistance, and a fabric containing the dyed para-aramid fibers.

As a result of intensive studies to achieve the above object, the present inventors
An aramid fiber is added with 1-40 g / l of an alkali metal salt and / or an alkaline earth metal salt that is not basic in an aqueous solution in a dyeing bath (in an aqueous solution), and a dyeing solution containing the aqueous solution and an organic dye is added. It is based on the finding that by dyeing with a cationic dye in an aqueous solution having a pH of 2 to 5.5, it becomes possible to stably achieve high definition and high light resistance. That is, according to the present invention,
A method for dyeing para-aramid fibers, characterized by dyeing para-aramid fibers to which buckling portions (kinks) are imparted according to the following requirements.
a) Containing 1 to 40 g / l of an alkali metal salt and / or alkaline earth metal salt that does not have basicity when made into an aqueous solution.
b) Performing in the presence of a carrier having a fiber structure relaxing action or an apparent glass transition point lowering action.
c) The pH of the staining solution is 2 to 5.5.
d) Dyeing with cationic dyes.
And a dyed structure comprising the same and having high light fastness.

  By the dyeing method of the present invention, it is possible to obtain a para-aramid fiber having high clarity and high light fastness, so that it is excellent not only in safety functionality but also in aesthetic sense as protective clothing, work clothing, or interior materials. .

The para-aramid fiber in the present invention is a fiber made of polyamide having an aromatic ring in the main chain, and is a fiber made of poly-p-phenylene terephthalamide (PPTA). Here, PPTA is a polymer obtained by polycondensation of terephthalic acid and paraphenylenediamine, but a copolymer obtained by copolymerizing a small amount of dicarboxylic acid and diamine can also be used, and the molecular weight of the copolymer is usually 20,000. ~ 25,000 is preferred. The aramid fiber is prepared by dissolving the PPTA in concentrated sulfuric acid, extruding the viscous solution from a spinneret, spinning it in air or water, and then neutralizing with an aqueous sodium hydroxide solution. Specifically, it is obtained by drying and heat treatment at 120 to 500 ° C.
In addition, the fiber as used in this invention represents the fiber structure containing a staple fiber, a sliver, a top, a spun yarn, a check thread, a nonwoven fabric, a knitted fabric, etc.

  Here, it is preferable that the para-aramid fiber before drying / heat treatment has a crystal size (110 face) of less than 50 mm and becomes 50 mm or more after drying / heat treatment. Furthermore, para-aramid fibers have a moderate loosening in molecular structure even when the strength deterioration rate when heat-treated at 420 ° C. for 1 minute is 10% or more, and the buckling portion (kink band) is Since it is easily formed, penetration of the dye occurs, and it is easy to be dyed, which is preferable. However, when the strength deterioration rate exceeds 40%, the flame retardancy and flameproofness are inferior, and the LOI of the fiber structure may decrease to less than 27.0, which is not preferable.

  The para-aramid fiber used in the present invention has a dry heat shrinkage rate of 400 ° C. of preferably 10% or less, more preferably 5% or less, thereby reducing burn damage due to flame exposure, and a fiber structure. Can be easily set to 27.0 or more.

  Furthermore, the para-aramid fiber in the present invention needs to have a buckling portion (kink band), and thereby dyeability is remarkably improved, which is comparable to the hue of the meta-colored aromatic polyamide fiber colored with the raw material. Excellent hue can be realized. Moreover, even if this is combined with a raw material-colored meta-aromatic polyamide fiber, no irritation occurs, and a fiber structure having a visually improved quality can be obtained as a fiber structure.

  The buckling part (kink band) is formed by para-polyamide fiber by physical means. The physical means are not only crimps such as indentation-type crimps, but also strong hits (tapping), surface friction. The invention is not limited to these as long as it can form (provide) a buckled portion (kink band) such as a bent portion by physical means, such as (iron), twisted yarn, and false twist.

  Furthermore, in the present invention, the para-aramid fiber is added with 1 to 40 g / l of an alkali metal salt and / or alkaline earth metal salt that is not basic when it is made into an aqueous solution in a dyeing bath (in an aqueous solution). is necessary.

Alkali metal salts and / or alkaline earth metal salts that are not basic when made into an aqueous solution indicate basicity when alkali metal salts and / or alkaline earth metal salts that do not have basicity are dissolved in pure water. Specific examples include sodium sulfate, sodium nitrate, sodium hydrochloride and the like. Does not contain sodium acetate, calcium acetate, etc.
In this case, if the addition amount is less than 1 g / l, the dye solubility is high and distribution to the fiber may be suppressed, which is not preferable. If it exceeds 40 g / l, the solubility is decreased, which is not preferable.

Next, it is necessary to dye in the presence of a carrier having a fiber structure relaxing action or an apparent glass transition point lowering action. Carriers that have fiber structure relaxation or apparent glass transition point lowering effects include methanol, ethanol, propanol, isopropyl alcohol, benzyl alcohol, acetone, acetophenone, NMP, DMSO, DMF, ethylene glycol, acetonitrile, propylene, or ethylene glycol phenyl ether Alternatively, dyeing is performed using at least one selected from commercially available carriers and swelling agents, but it is necessary to use a carrier that is suitable for the dyeing environment (processing capacity, working environment, etc.) and that reduces the environmental load. preferable. The preferred amount of use varies depending on the ratio of the amount of fiber to the dyeing solution (bath ratio), but is 2 to 150% of the total weight of the fiber.
By dyeing in the presence of the above carrier (swelling agent), the fiber crystal part is swollen and the dye can easily permeate, and a synergistic effect can be exhibited.

  It is important that the dyeing solution containing the cationic dye has a pH of 2 to 5.5. When dyeing under these conditions, an excellent hue, sharpness and light resistance can be exhibited, which is preferable. Here, if the pH of the dyeing solution is less than 2, it is not preferable in terms of metal corrosion and handleability, and if it exceeds 5.5, the dye solubility is suppressed and high dyeability is not obtained, which is not preferable. Preferably it is pH 2-4.

  The cationic dye used in the present invention refers to a water-soluble dye having a basic group that is soluble in water and is used for dyeing acrylic fibers, natural fibers, cationic dyeable polyester fibers, and the like. There are di- and triacrylmethane-based, quinoneimine (azine, oxazine, thiazine) -based, xanthene-based, methine-based (polymethine, azamethine), heterocyclic azo-based (thiazoleazo, triazoleazo, benzothiazoleazo), anthraquinone-based, and the like. Recently, there is a cationic dye which is made water-dispersible by blocking a basic group, but both can be used.

The dyeing temperature is preferably 115 ° C or higher and 150 ° C or lower, more preferably 120 ° C or higher. If the dyeing temperature is 115 ° C. or lower, the dyeability may be insufficient. Also, the higher the dyeing temperature, the higher the dyeing property, but on the other hand, if the dye is decomposed or aramid fiber is combined with other materials, problems of deterioration of the composite material will begin to occur. About 140 ° C. is preferable even if it is not high.
By dyeing with the dyeing method of the present invention as described above, even if mixed with the meta-aramid fiber and dyed, no irritation occurs and a fabric with improved color perception can be obtained.

  Although it is not clear why the para-aramid fibers having a buckled portion have high sharpness and high light resistance by dyeing under the conditions of the present invention, the pH should be dyed on the acidic side of 2 to 5.5. As a result, the dye and alkali metal salt / earth metal salt form a complex, reduce the apparent solubility of the dye, salt out (dye) on the fiber interface, improve the dye density and diffusion, and evenly diffuse inside the fiber It is presumed that the light resistance is remarkably improved by dyeing and exhibiting high definition and increasing the dyeing concentration at the fiber interface.

Hereinafter, an example is given and the composition and effect of the present invention are explained in detail.
In addition, the evaluation method of the to-be-dyed object performed by the Example / comparative example was performed according to the following method.
・ PH measurement:
The pH of the alkali metal salt or alkaline earth metal salt in an aqueous solution of 0.5 mol / L was measured with a digital pH meter HM-60 (manufactured by Toa Denpa Kogyo).
-Lightness index L *: The tristimulus value Y specified in JIS Z 8701 (color display method by 2 degree visual field XYZ system) or JIS Z 8728 (color display method by 10 degree visual field XYZ system) It is obtained from the formula.
L * = 116 (Y / Yn) 1-3-16
Y / Yn> 0.008856
Y: Tristimulus value in XYZ Yn: Y value of standard diffuse reflection surface. However, when Y / Yn is 0.008856 or less, the following equation is used.
L * = 903.29 (Y / Yn)
Y / Yn ≦ 0.008856
Thus, the brightness index L * value was obtained. The lightness index L * indicates that the smaller the value, the deeper the dyeing.
The degree of sharpness can be expressed by the lightness L * value and the saturation C * value by the color difference formula (CIE encouragement) based on the L * a * b * h color system.
In this case, when the lightness L * value is approximately the same, the larger the saturation C * value, the better the clear and high color developability.
-Light resistance: Based on JIS L 0842, it judged after irradiation for fade 20 hr.

[Example 1]
Poly-p-phenylene terephthalamide (hereinafter referred to as PPTA, IV = 6.5) obtained by a usual method is dissolved in 99.9% concentrated sulfuric acid to form a spinning dope having a polymer concentration of 19.9% and a temperature of 80 ° C. It is discharged from the base (0.01mmφ × 1000H), water solidified, then neutralized in an alkali bath, dried, heat treated, oiled in the usual way, crimped as a physical treatment, then cut Teijin Twaron (TW1072) was obtained.
Using this fiber, sodium sulfate is used as an alkali metal salt and / or alkaline earth metal salt (hereinafter abbreviated as “treatment agent”) as follows (130 ° C. × 60 minutes, bath ratio 1:20, pH 2. 59).
・ C. I. Basic Orange 22 6% owf
・ Acetic acid (50%) 0.3cc / l
・ Dispersant (Disper VG: Daiichi Kogyo Seiyaku Co., Ltd.) 0.5 g / l
・ Sodium sulfate 20 g / l
・ Benzyl alcohol 70 g / l

[Example 2]
In Example 1, the treatment was performed and evaluated in the same manner as in Example 1 except that sodium nitrate was used as the treatment agent to be put into the dyeing bath.

[Example 3]
In Example 1, it processed and evaluated similarly to Example 1 except having used sodium chloride as the processing agent thrown into the dyeing bath.

[Example 4]
In Example 1, the treatment was performed in the same manner except that calcium chloride was used as the treating agent to be put into the dye bath.

[Comparative Example 1]
In Example 1, it processed and evaluated similarly to Example 1 except having used potassium acetate as the processing agent thrown into the dyeing bath.

[Comparative Example 2]
In Example 1, the treatment was performed in the same manner as in Example 1 except that sodium acetate and sodium nitrate were used at 20 g / l as the treating agent to be put into the dyeing bath.

[Comparative Example 3]
In Example 1, it evaluated and processed similarly to Example 1 except having set it as sodium acetate as a processing agent thrown into a dyeing bath.

[Comparative Example 4]
In Example 1, it carried out similarly except not using sodium sulfate.

[Comparative Example 5]
The same procedure as in Example 1 was carried out except that the staining solution had a pH of 6.0.

[Comparative Example 6]
In Example 1, the same treatment was performed and evaluated except that the amount of sodium sulfate used in the dyeing bath was changed to 0.5 g / l.

[Comparative Example 7]
In Example 1, the treatment and evaluation were carried out in the same manner except that the amount of sodium sulfate used in the dyeing bath was 50 g / l.

  According to the present invention, the para-type aromatic polyamide having properties such as high strength, flame retardancy, and light weight can be imparted with high sharpness and high light fastness. Applications can be expanded to the general clothing field.

Claims (4)

A method for dyeing para-aramid fibers, characterized by dyeing para-aramid fibers to which buckling portions (kinks) are imparted according to the following requirements.
a) An alkali metal salt and / or an alkaline earth metal salt that does not have basicity when made into an aqueous solution.
b) Performing in the presence of a carrier having a fiber structure relaxing action or an apparent glass transition point lowering action.
c) The pH of the staining solution is 2 to 5.5.
d) Dyeing with cationic dyes.   The method for dyeing para-aramid fibers according to claim 1, wherein the addition amount of the alkali metal salt and / or alkaline earth metal salt, which is not basic when an aqueous solution is used, is 1 to 40 g / l.   Para-aramid fibers dyed by the method according to claim 1.   A fabric comprising para-aramid fibers dyed by the method according to claim 1.