JP2934767B2 - Dyeing method of aromatic polyamide fiber - Google Patents

Description

The present invention relates to a method for dyeing wholly aromatic polyamide fibers,
The present invention relates to a method for pre-treating the fiber with a specific solvent to improve dyeability.

(Prior Art) The wholly aromatic polyamide (hereinafter abbreviated as aramid) fibers include meta-aramid fibers represented by Nomex and Conex, and para-aramid fibers represented by Kepler and Twaron.

These aramid fibers have thermal properties such as flame retardancy and heat resistance, and chemical properties against various chemicals and solvents, compared to aliphatic polyamide fibers widely used in the past such as nylon 6 and nylon 66. Excellent safety.

For this reason, it has begun to be widely used for clothing such as protective clothing requiring flame retardancy and heat resistance, for industrial materials such as back filters, and for interiors such as curtains.

Aramid has the above characteristics due to its rigid molecular chain and high crystallinity, but on the other hand, it has the disadvantage of being difficult to dye.

Conventionally, many methods for dyeing meta-aramid fibers have been proposed, but satisfactory results have not been obtained. For example, Textile Research Journal (VOL.56, P254-261,198
According to 6), as a recent result, there has been proposed a method of improving the Nomex fiber structure using chemical energy from a solvent to improve the dyeability.

That is, a modification method using DMF, DMAc, and DMOS having extremely high polarity has been proposed, but has the following problems and has not been put to practical use.

In these methods, the contraction of the aramid fiber is large,
Lack of dimensional stability.

The cross section of the dyed product according to the present method is as shown in FIG. 2, and there are various patterns of dye penetration, showing very irregular dye penetration, and easily causing spotting.

 Low mechanical properties of fiber.

The solvent used is highly toxic and corrosive, making industrial implementation difficult.

As another method of improving dyeability, a functional group having an affinity for the dye molecule is introduced into the aramid molecule itself (Japanese Patent Publication No.
Attempts to make it porous or to make it porous (such as Japanese Patent Publication No. 52-43930), but the effect of improving the dyeing properties is insufficient, and the heat resistance characteristic of aramid is reduced. have.

On the other hand, para-aramid fibers are more difficult to dye, and industrial dyeing is hardly performed.

<Problems to be Solved by the Present Invention> As described above, many studies have been made on improving the dyeability of aramid fibers.

However, there is no method for improving dyeability, which is safe and industrially feasible, while maintaining the original properties of aramid fiber such as heat resistance, flame retardancy and physical fiber properties. At present, it relies on the moist spinning method.

On the other hand, the soaking method has a problem that a clear hue cannot be obtained and it is difficult to apply the method to small lot production.

<Means for Solving the Problems> In view of the above situation, the present inventors have conducted various studies to improve the dyeability of aramid fibers, and as a result, have achieved the present invention.

That is, in the present invention, when dyeing aramid fiber, the fiber is treated with 100% by weight of N-methyl-2-pyrrolidone.
Immersion in a solution or an aqueous solution of 75% by weight or more
This is a method for dyeing aramid fibers, which comprises performing a pretreatment of squeezing to ~ 200% and holding at 10 to 40 ° C for 5 to 48 hours.

The main constituents of the present invention are aramid and a wholly aromatic polyamide in which an amide bond is directly linked to an aromatic compound, and examples thereof include (a) an aromatic polyamine and an aromatic polycarboxylic halide; and (b) Such as (C) aromatic polyamine and aromatic polycarboxylic acid, (d) aromatic polyisocyanate and aromatic polycarboxylic acid, and the like. A polymer obtained by polycondensing a combination.

Among them, aramid having an aromatic nucleus bound by meta-meta or meta-para has an excellent balance between strength and elongation, and is suitable as the aramid of the fiber of the present invention.

For example, a typical example is a meta-meta-bonded aramid mainly composed of polymetaphenylene isophthalamide obtained by low-temperature solution polymerization or interfacial polymerization of metaphenylenediamine and isophthalic chloride. Further, it can be used for an aramid having an aromatic nucleus substituted with an alkyl group such as a methyl group.

The method for dyeing aramid fibers of the present invention can also be used for mixed cotton, mixed fibers or mixed fabrics of aramid fibers and other fibers.

The fiber material to be mixed with the aramid fiber is not particularly limited as long as it is a fiber material which is hard-fixed or does not dissolve by the solvent treatment described below. , Flame retardant vinylon,
Flame retardant materials such as Nopolak are preferred.

Among them, when a flame retardant material such as a flame retardant rayon is mixed, aramid alone becomes more hygroscopic and more preferable in terms of comfort.

The shape of the fiber to which the present invention is applied may be raw cotton, filament, spun yarn, or the like, but is preferably a two-dimensional material such as a woven fabric, a knitted fabric, or a nonwoven fabric.

 Furthermore, it can be applied to final textile products such as sewn products.

In addition, with other fiber materials, it may be blended with raw cotton,
A spun yarn or a filament-shaped yarn may be cross-woven or knitted.

N-methyl-2-pyrrolidone may be used at 100% by weight, but may be mixed with water.

 The mixing amount of water is preferably 25% by weight or less.

If it exceeds 25% by weight, the effect of improving the dyeability by the solvent treatment cannot be satisfied.

Other substances and / or solvents can be mixed with the solvent for dyeing pretreatment within a range that does not impair the effects of the present invention.

The aramid fiber is added to the above solvent for a short time (for example, 1 to 10
S) soak.

The immersion referred to in the present invention is a method of immersing the yarn in the treatment liquid, a method of attaching the yarn by spraying or the like, and a method of immersing the yarn in the treatment liquid is preferable in terms of effect and economy.

 Next, it is squeezed so that the squeezing rate becomes 30 to 200%.

If the squeezing rate liquid is less than 30%, the solvent treatment effect becomes unsatisfactory. If the squeezing rate exceeds 200%, the effect becomes saturated and it is not economical.

When squeezing a cloth-like material, it is preferable to use a solvent-resistant mangle so that uniform squeezing is possible. The squeezing rate is 50-150%
Is more preferable.

 The squeezing rate according to the present invention was determined by the following equation.

After squeezing a predetermined amount of the solvent, the mixture is kept at 10 to 40 ° C. for 5 to 48 hours.

When the temperature is less than 10 ° C. or the time is less than 5 hours, the effect of improving the dyeability by the solvent treatment is unsatisfactory. If the temperature exceeds 40 ° C., the swelling and dissolution by the solvent becomes large, the feeling hardens, and the strength becomes low, which is not preferable. In addition, even if it exceeds 48 hours, the effect of improving the dyeing is small and inefficient. More preferable holding conditions are a temperature of 15 to 30 ° C. and a time of 12 to 36 hours.

As a method for holding the yarn, if the shrinkage of the yarn is adjusted to 0.1 to 3%, it is possible to suppress the change in the feeling of aramid fiber material or nonwoven fabric, and also from the viewpoint of dimensional stability. preferable.

As a specific method, there is a pad rolling method and the like.

The pad rolling method is a method of processing a cloth-like article by immersing the cloth-like article in a predetermined liquid, squeezing the liquid, winding up the beam or the like, and then rotating the cloth-like article so as to be uniformly processed by the liquid. .

When this method is used, rolling is performed at a rotation speed of 0.5 to 20 seconds / times. When the rotation speed is less than 0.5 seconds / times, the solvent moves to the outside from the center due to the centrifugal force, resulting in processing unevenness. When the rotation speed exceeds 20 seconds / time, the influence of gravity is far greater than the centrifugal force, resulting in processing unevenness.

 More preferably, the rotation speed is 2 to 10 seconds / times.

In addition, it is convenient to cover the cart with a vinyl sheet or the like during rolling, so that adhesion of dust or the like can be prevented.

After holding the aramid fiber for a predetermined processing time, it is subjected to blanching and washing with an open soaper or a liquid flow type facility, and then dyed.

Aramid fiber that has been subjected to solvent pretreatment is a cationic dye,
Disperse dyes, basic dyes, acidic metal-containing dyes, sulfur dyes, can be dyed with any dye such as a dye, but a relatively small molecular weight, cationic dye, disperse dye, when dyed with a basic dye, the present invention Since the effect of improving the dyeability by the solvent pretreatment is remarkable, it is preferably applied to low molecular weight dyes.

As the dyeing conditions, the dyeing temperature is preferably from 110 to 140 ° C., and the temperature holding time is preferably from 10 to 120 minutes.Moreover, as a dyeing accelerator, phthalic acid, an aromatic ether, a phenylphenol-based carrier such as 2 to 20 g is used. / L, or 5 to 100 g / L of inorganic salts such as sodium sulfate and sodium nitrate. FIG. 1 shows Example 1 of the present invention described later.
1 shows an enlarged cross-sectional view of the aramid fiber dyed product obtained in 1.

From this, there is no irregular dye permeation but uniform permeation, which is a marked difference from FIG.

Although the cause is not clear, it is considered to be the effect of the solvent pretreatment conditions specified in the present invention.

<Effects of the Present Invention> According to the present invention, by pretreating the aramid fiber with a solvent under specific conditions, the dyeability of the aramid fiber, which has been considered extremely difficult, can be dramatically improved.

<Example> An embodiment of the present invention will be described with a specific example. The percentages in the examples relate to weight unless otherwise specified.

The refining and presetting process in the examples is to remove the stains on the cloth-like material with a detergent, and to fix the cloth width preliminary,
For example, it is a processing method of a cloth state in which heat treatment is performed at 170 to 200 ° C. for 5 to 30 seconds.

In the measurement of the dyeing property in Table 1, the visible spectrum of the dyed cloth is taken, and the reflectance at the wavelength showing the maximum peak is determined. The dyeing of the present invention is performed by multiplying the reflectance at the maximum peak wavelength of the dyed cloth subjected to the treatment of the present invention to the maximum peak wavelength of the dyed cloth not subjected to the treatment of the present invention with respect to the reflectance at the maximum peak wavelength. The effect of improving the properties was shown.

(Example 1) After a predetermined refining and presetting of a satin woven fabric (having a basis weight of about 240 g / m ² ) composed of polymetaphenylene isophthalamide,
It is immersed in a 95% aqueous solution of N-methyl-2-pyrrolidone, squeezed with a solvent-resistant mangle (100% squeezing rate), and rolled up on a dedicated cart. Cover it with a vinyl sheet, about 30
It is kept for 24 hours in a room controlled at ° C. while rotating at a rate of about 2.5 seconds / time.

Then, blanch with a liquid flow type dyeing machine and wash with water for about 30 minutes.
Do for a minute.

 Then, staining was performed under the following staining conditions.

Dyeing color: CI Disperse Red 302 Concentration; 5% owf Carrier; Carlon AW 5 g / L (Katsumata Kasei) Inorganic salts; Sodium nitrate 60 g / L Bath ratio; 1:20 Temperature; 135 ° C time; 45 minutes NMP The woven fabric after the refining and pre-setting without pre-treatment was dyed under the same conditions, and the color density of the dyed product was compared with the color density of the dyed product subjected to the solvent treatment.

(Example 2) Plain woven fabric obtained by blending polymetaphenylene isophthalamide and flame-retardant polynosic fiber in a ratio of 65:35 (basis weight: about 180 g /
After refining and presetting m ² ), it is immersed in a 100% solution of N-methyl-2-pyrrolidone, squeezed with a solvent-resistant mangle (squeezing rate 90%), and wound up on a dedicated cart.

Cover it with a vinyl sheet and rotate it in a room controlled at about 20 ° C for about 2.5 seconds / time.
Hold for 4 hours.

Thereafter, it was blanched with a liquid-flow type dyeing machine, washed with water for about 30 minutes, and dyed under the following ship-side conditions.

Dyeing agent: Kayacryl Navy RP-ED (Nippon Kayaku) Concentration: 10% off Carrier: Katsuron AW 5g / L (Katsumata Kasei) Inorganic salts: Sodium sulfate 60g / L Bath ratio: 1:20 Temperature: 135 ° C Time: 60 minutes The fabric after refining and presetting without NMP pre-treatment is dyed under the same conditions, the color density of the dyed material is compared with the color density of the solvent-treated dyed material, and the magnification is shown. 1 is shown.

Example 3 A plain woven fabric (having a basis weight of about 190 g / m ² ) composed of polymetaphenylene isophthalamide was treated with N-methyl-2-pyrrolidone 80.
% Aqueous solution, squeeze it with a solvent-resistant mangle (squeezing rate about 100%), and wind it up on a special cart.

Cover it with a vinyl sheet and rotate it in a room controlled at about 30 ° C for about 2.5 seconds
Allow time to dwell.

Thereafter, it was blanched with a liquid-flow type dyeing machine, washed with water for about 30 minutes, and dyed under the following dyeing conditions.

Dyeing: Dianix Navy Blue GR-SE (Mitsubishi Kasei) Concentration: 5% owf Carrier: Katron AW 5g / L (Katsumata Kasei) Inorganic salts: Sodium sulfate 60glL Bath ratio: 1:20 Temperature: 135 ° C time ; 45 min.Dye fabrics without NMP pretreatment under the same conditions,
The color density of the dyed product was compared with the color density of the dyed product subjected to the solvent treatment, and the magnification was shown in Table 1.

The dyeability in Examples 1, 2, and 3 was as follows.

From these results, it was found that the present invention was remarkably deeply dyed as compared with the case without the pretreatment, a practical hue could be obtained, and the present invention was effective.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a dyed fiber obtained in Example 1. FIG. 2 shows a typical dye permeation (shaded area) pattern and a temporary image of a solvent-treated Nomex fiber.

Claims (1)

(57) [Claims] (1) When dyeing a wholly aromatic polyamide fiber, the fiber is treated with 100% by weight of N-methyl-2-pyrrolidone.
Immersion in a solution or an aqueous solution of 75% by weight or more
A method for dyeing a wholly aromatic polyamide fiber, comprising performing a pretreatment of squeezing to ~ 200% and holding at 10 to 40 ° C for 5 to 48 hours.