JPH11152690A - Dyeing of very thin polyamide-based fiber-structured material and dyed material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vividly-colored dyed material having a sufficient color developing property and wet fastness by dyeing a very thin polyamide-based fiber-structured material with a specific reaction dyestuff and then adjusting pH in a specific range for wet heat-treating. SOLUTION: This method for dyeing a very thin polyamide-based fiber- structured material is to dye the fiber-structured material of 0.0001-1 de single fiber thickness in a dyeing liquid containing at least one kind selected from the group of vinylsulfon group or a reactive group forming the same, a monohalogenated triazine group, bromoacrylamide group, carboxypyridinyltriazine group and fluorochloropyrimidine group and adjusted at pH3-8, wet-treat the fiber-structured material at pH 6-13 after imparting either one of pH shift agent or a weak alkali generating agent capable of shifting pH to pH8-13 at a temp. of <=60 deg.C, and then performing a soaping treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dyeing an ultrafine polyamide fiber structure and a dyed product.

[0002]

2. Description of the Related Art It is known that an ultrafine polyamide fiber structure having a single fiber fineness of 1 denier or less has a larger surface area than a polyamide fiber structure having a normal fineness, so that the apparent surface concentration is reduced. I have. Further, if the ultrafine fiber is less than 1 denier, the dense amorphous portion which is effective for dyeing is reduced, and the dye is exhausted but not fixed. Even if a sufficient amount of color is obtained by using a large amount of dye, it is inferior in wet fastness such as washing fastness and has many practical problems. At present, such a problem has not been solved even by using a metal complex dye having relatively good wet fastness and color development.

[0003] Against this background, several methods have been proposed for satisfying the sufficient color-forming property and wet fastness of an ultrafine polyamide fiber structure. For example, Tokiko 6-15
No. 750 discloses a method of dyeing a polyamide ultrafine fiber with a neutral type metal complex dye and then performing a fix treatment with tannic acid and a metal salt of 8% owf or more. This method is a technique for preventing exfoliation of the dye by confining the dye that has been exhausted in the fiber, thereby improving the color developability and the fastness. However, in this method, there is a problem that the hue becomes dark by using the complex salt dye, the clearness cannot be sufficiently expressed, and the texture becomes slightly hard, and another method is desired. Is the actual situation.

[0004] Japanese Patent Application Laid-Open No. 6-306780 discloses a method in which tannic acid fix is further reduced and washed. This method improves the wet fastness of the dyed material by removing in advance by washing the dye that has not been encapsulated by the fix treatment, but on the contrary, it has a problem in that the color developability is reduced and it is difficult to express dark colors. There was a problem.

[0005] As described above, the current technology is not perfect, and at present, it is not possible to fully satisfy the wet fastness with a dark color. Further, the wet fastness of the metal complex dye is better than that of the acid dye, but there is a problem that the hue becomes dark and a clear color cannot be expressed. Accordingly, there has been a demand for a method for dyeing an ultrafine polyamide fiber structure which is clear and has good wet fastness properties.

[0006]

SUMMARY OF THE INVENTION In view of the background of the prior art, an object of the present invention is to provide a method for dyeing an ultrafine polyamide fiber structure capable of achieving sufficient color development and wet fastness and expressing a clear hue. Is to be provided.

[0007]

The present invention employs the following means in order to solve the above-mentioned problems.

That is, the method for dyeing an ultrafine polyamide fiber structure of the present invention mainly comprises a single yarn fineness of 0.0001.
When dyeing a polyamide fiber structure having a denier of 1 to 1, it is characterized by dyeing with a dye solution adjusted to pH 3 to 8 containing a reactive dye.

The dyed product of the ultrafine polyamide fiber of the present invention is a dyed product obtained by the above-mentioned dyeing method. In another embodiment, the single yarn fineness is mainly 0.0001 to 1
A denier polyamide-based fiber structure is dyed with a reactive dye, and has a wash fastness of 3 or more as defined in JIS L-0844, and a light fastness of 3 or more as defined in JIS L-0842. It is characterized by the following.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION 0.0001-1 in the present invention
The denier ultrafine polyamide fiber structure may be any fiber structure including polyamide fibers having a single yarn fineness of 0.0001 denier to 1 denier, regardless of the production method.
The amount of the amino terminal group to be contained is not particularly limited, and 3 × 1
Those having 0 ^-5 eq / g to 25 × 10 ^-5 eq / g can be used. It is not necessary to use the same amount of amino terminal groups. For example, the amount of amino terminal groups is 3 to 5 × 10 ^−5.
eq. / G of polyamide fiber and 8 to 25 × 10 ⁻⁵ e
q. / G polyamide-based fibers in a ratio of 8/2 to 2/8. Other fibers such as synthetic fibers such as polyester, polyurethane, and acrylic, natural fibers such as cotton, hemp, silk, and wool, and semi-synthetic fibers such as rayon and Tencel may be contained in addition to the ultrafine polyamide fibers. Further, a synthetic polymer such as polyester, acrylic, polyurethane or the like may be added to these by coating or impregnation. In addition to the single yarn fineness, a mixture of a normal denier polyamide fiber may be used. Even if the single fiber fineness is outside the above range, it is possible to dye according to the present invention, but the difference in fastness is small as compared with conventionally used acid dyes. In the present invention, the method is useful for an ultrafine polyamide fiber structure having a denier of 1 denier or less, preferably 0.5 denier or less, and more preferably 0.1 denier or less.

The method for producing the ultrafine polyamide fiber is not particularly limited. For example, a fiber obtained by removing the sea component of the sea-island type multicomponent fiber, a fiber obtained by peeling from the peelable fiber, a direct melt spinning Can be used. The structure of the fiber structure of the present invention is not particularly limited, and includes a sheet-like structure such as a woven fabric, a knitted fabric, and a nonwoven fabric. In the case of artificial leather made of a non-woven fabric or the like, a mixture of fibers having different fiber finenesses, for example, a mixture of fibers having different fiber finenesses is used.
When the present invention is applied to a mixture in which fibers of 01 to 0.2 denier and 0.001 to 0.1 denier are mixed in a weight ratio of about 8/2 to 2/8, it is possible to obtain a fiber having excellent color developability. it can.

The anionic reactive dye used in the present invention generally refers to a dye having a reactive group having a covalent bond to a hydroxyl group or an amino group. For example, a monochlorotriazine group (X = Cl, Y = substituent), a monofluorotriazine group (X = F, Y = substituent), a carboxypyridiniotriazine group (X = formula [II], Y = substituent), dichlorotriazine group (X = Y = Cl), etc.
At least one known reactive group such as a vinylsulfone group or a sulfatoethylsulfone group represented by [III], a fluorochloropyrimidine group or a trichloropyrimidine group represented by the formula [IV], or a bromoacrylamide group represented by the formula [V]; It is a dye having one or more dyes, but is not limited thereto. For example, a known reactive group described in, for example, "Kyosen Dye Chemistry" (Shinsen Co., Ltd.) can be applied.

The dye is not particularly limited as long as it has one or more of these reactive groups. For example, a dye having two or more monochlorotriazine groups of the formula [I] in a molecule, a dye having the formula
A different reactive group type dye containing the monochlorotriazine group or monofluorotriazine group of [I] and the sulfatoethylsulfone group of formula [III] in the same molecule may be used. For example, in formula [I], Y may include formula [III].

[0014]

Embedded image

Embedded image

Embedded image (In the formula, Z is -CH = CH ₂ or -CH ₂ C
H ₂ Z ¹ represents Z ¹ -OSO ₃ H, -OCOCH ₃ , -O
PO ₃ H _2, a leaving group of -Cl, etc.)

Embedded image (Where X _{1 to} X ₃ are Cl or F)

Embedded image Dyes having such a reactive group include, for example, Sumi
fix, Sumfix Supra, Remazo
1, Celmazol, Levafix, Procio
n, Cibacron, Basilen, Drimar
ene, Drimalan, Lanasol, Kaya
Cion, Mikacation, Kayaceron R
Eact, Verofix, Realan and the like can be used. Although any reactive dye can be applied to the present invention, among them, a reactive group forming a vinyl sulfone group or a vinyl sulfone group, a monohalogenated triazine group such as a monochlorotriazine group or a monofluorotriazine group, a bromoacrylamide group, a carboxypyridinio group Dyeing with a reactive dye having at least one of a triazine group and a fluorochloropyrimidine group is preferable because the fastness can be further improved. Here, the reactive group forming a vinyl sulfone group refers to a vinyl sulfone group protected by a leaving group such as a sulfatoethyl sulfone group. Further, in terms of color development, a monohalogenated triazine group such as a monochlorotriazine group or a monofluorotriazine group, a bromoacrylamide group, a carboxypyridiniotriazine group,
A heteropolyfunctional reactive dye having at least one fluorochloropyrimidine group and having at least one vinyl sulfone group and / or a reactive group forming a vinyl sulfone group is preferred. As these dyes, commercially available ones can be appropriately used,
For example, Sumfix Supra dye (manufactured by Sumitomo Chemical Co., Ltd.), Cibacron dye (manufactured by Ciba Specialty Chemicals Co., Ltd.), Lanasol dye (manufactured by Ciba Specialty Chemicals Co., Ltd.), Procion dye (manufactured by Mitsui BASF Dye Co., Ltd.), Kayacation Dye (manufactured by Nippon Kayaku Co., Ltd.), Kayaceron Rea
ct dye (manufactured by Nippon Kayaku Co., Ltd.), Basilen dye (manufactured by Mitsui BASF Co., Ltd.), Drimalan F dye (manufactured by Clariant Co., Ltd.), Drimarene dye (manufactured by Clariant Co., Ltd.), Realan (Dystar Co., Ltd.) Manufactured) can be used.

In the dyeing method of the present invention, the pH of the liquor is 3
-8, preferably 4-7, more preferably 4-5.5, from the viewpoint of improving the dye utilization rate or the exhaustion rate. When the pH is less than 3, the exhaustion rate increases, but the fastness of the dyed product decreases. If the pH is more than 8, the exhaustion rate and the utilization rate decrease, so that a deep color cannot be expressed, and the utilization rate of the dye is small, which is disadvantageous in terms of drainage load and economy. For pH adjustment, an acid or a buffer can be appropriately prepared. The acid or salt used at that time is not particularly limited. As the acid generator, acetic acid, formic acid, hydrochloric acid and the like can be used, and a pH sliding agent such as ammonium sulfate can also be used. As the buffer, those prepared with acetic acid and sodium acetate can be used. In addition, the effects of the present invention can be achieved without adding any components other than the dye and water, provided that the pH is achieved.

The dyeing liquor of the present invention may contain, if necessary, salts, surfactants, leveling agents, fastness improvers, reduction inhibitors and the like, in addition to the above constituent substances.

In the present invention, various known dyeing methods such as dip dyeing, printing and padding dyeing can be used. In the case of dip dyeing, treatment is carried out at 60 ° C. or more, preferably 90 ° C. to 130 ° C., and in printing and padding dyeing. First, as a color paste,
The reactive dye of the present invention and a sizing agent are used at pH 3 to 8, preferably 4
-5, more preferably 4 to 5.5, and then a wet heat treatment with a saturated or heated steam, heat-sensitive heat treatment, or microwave irradiation at 80 to 130 ° C. for about 10 to 30 minutes. In the case of dyeing and dyeing, when using a dye having at least one reactive group which forms an alkaline vinyl sulfone group, the dye, an auxiliary agent, and water are added before the polyamide fiber structure is put into the dyeing solution. After mixing, pH 8
１３13, and heated at 70-100 ° C. for about 5-20 minutes to form a vinyl sulfone group.
After returning to 8, the polyamide fiber structure may be charged and dyed.

[0018] By these methods, a sufficient coloring property and fastness of the dyed product can be obtained. However, if it is necessary to further improve the fastness of the dyed product, the pH of the dyed product is not less than 60 ° C and a pH of 8 to 8 after dyeing. At least one selected from a pH sliding agent and a weak alkali generator which shifts to 13 is applied, and then a wet heat treatment can be performed. Dye concentration is 1
This is a particularly preferable method when a dark color of 0% owf or more is required. The pH slide agent is not particularly limited. For example, sodium trichloroacetate or the like or a commercially available pH slide agent (eg, Kaya Slide 509 (Nippon Kayaku Co., Ltd.)
Manufactured) can be used as appropriate. Also, the weak alkali generator is not particularly limited, and for example, sodium carbonate, sodium hydrogen carbonate, and the like can be used. Conventional techniques such as a pad method, a coating method, a spray method and the like can be used for applying. This treatment liquid preferably has a pH of 3 or more so as not to deteriorate the fastness at the time of application, and preferably has a pH of 12 or less for darkening. More preferably, the pH is adjusted to 4 to 9. Such p
When adding the H-sliding agent and the weak alkali generator, the effect is further improved by using inorganic salts and / or an anionic surfactant in combination. Such an agent may be applied simultaneously with the pH slide agent and / or the weak alkali generator, or may be applied in separate steps. Conventional techniques such as a pad method, a coating method, and a spray method can be used for applying such a drug.

The inorganic salts used in the present invention are not particularly limited, and for example, sodium sulfate, sodium chloride and the like can be used. The anionic surfactant can also be used without any particular limitation. In particular, a sulfosuccinic acid diester-type anionic surfactant is more preferably used because of its higher effect. Examples of the sulfosuccinic acid diester type anionic surfactant include sodium di-2-ethylhexyl sulfosuccinate, sodium di-1-methylheptyl sulfosuccinate, sodium di-1-methyl-4-ethylhexyl sulfosuccinate, sodium sulfosuccinate, and the like. Sodium acid di-n-octyl ester, sodium di-n-heptyl sulfosuccinate and the like can be used. By using these in combination with a pH slide agent and an alkaline generator, the color developability of the dyed product can be improved.

The amount of the inorganic salt or anionic surfactant to be applied can be appropriately adjusted so as to obtain a desired concentration. The applied amount is preferably 0.5% to 20%
owf, more preferably 1 to 10% owf.
If the amount given is too large or too small, the effect will be halved,
It is preferable to provide within the above range.

In the dyeing method of the present invention, fixation and / or soaping can be performed after dyeing or after the above-mentioned wet heat treatment. As the fixing agent, an ordinary fixing agent can be used. In the case of ultrafine fibers, it is preferable that the amount of the fixing agent is larger than usual, for example, 5% owf or more from the viewpoint of wet fastness. From the viewpoint of keeping the texture of the fabric good, it is preferable to set it to at most 20% owf. To apply the fixing agent, for example, two-stage treatment with tannic acid and tartar, one-bath treatment with synthetic tannic acid, or the like can be used.

In the present invention, the soaping treatment is
A process to remove unfixed dyes or dyes that are easily stained and dyed with weak bonding after dyeing.Fix that seals some unfixed dyes or dyes dyed with weak bonding with fibers. It is different from processing. This method is preferable because there is no hardening of the texture and no change in hue due to the fixing process. Such a soaping treatment is preferably performed at a pH of 6 or more in order to improve the wet fastness, and is preferably performed at a pH of 13 or less to prevent discoloration. More preferably, pH 8-12, further preferably, pH 10
Performing in step 12 has the effect of removing unfixed dyes more and improving fastness. A conventionally known surfactant or the like is appropriately added to the liquid adjusted by the above pH. The surfactant is not particularly limited, and for example, an anionic surfactant, a nonionic surfactant, or a combination thereof can be used.

In the dyed fabric obtained according to the present invention, for example, pyridine 2
Even when treated with a 0% aqueous solution or the like continuously at 100 ° C. for about 6 hours, the color of the fibrous structure remains. When such a treatment is applied to a material dyed with a conventional acid dye, most of the dye is dropped off and the color is slightly confirmed, or is in a state before dyeing.

The dyed article comprising the ultrafine polyamide-based fiber structure dyed by the method of the present invention can be obtained from JI
Washing fastness specified by SL-0844 is 3 or higher, and light fastness specified by JIS JIS L-0842 is 3 or higher, and it is clear, excellent in color development and wet fastness. It can be preferably used for applications.

[0025]

EXAMPLES All the percentages described in the examples represent% by weight,
% Owf represents the weight% of the dye or auxiliary agent with respect to the weight of the fabric. In each example, the following fabric and dyeing conditions,
Fixed conditions and soaping conditions were used.

(Fabrics a to c: terminal amino terminal group content 5 × 10 ⁻⁵ eq / g) Nylon 6 non-woven fabric having a single yarn fineness of 0.003 denier (fabric a) Nylon 6 non-woven fabric having 0.05 denier (fabric b) 2-denier nylon 6 non-woven fabric (fabric c) (fabric d) 0.05 × d terminal amino terminal group content of 12 × 1
0 ^-5 eq / g of fiber and 5 × 10 ^-5 eq / g of fiber 2:
Nonwoven fabric mixed in 8.

(Dyeing Conditions) 1. Dyeing (Examples 1 to 5, Comparative Examples 1 and 2) Dye concentration 5% owf buffer acetic acid / sodium acetate pH 4.7 Bath ratio 1:20 Temperature 98 ° C Time 60 minutes 2. Padding dyeing (Example 6, Comparative Example 3) Color paste Dye concentration 10% Sodium alginate 0.5% Ammonium sulfate 1% Water 88.5% Pickup rate 80% Moisture heat treatment Temperature 102 ° C Time 20 minutes (fixed condition) 2-stage treatment (1) Tannic acid 7% owf bath ratio 1:20 temperature 80 ° C time 20 minutes (2) Tartar 5% owf bath ratio 1:20 temperature 80 ° C time 20 minutes (soaping condition) Cleaning agent Grand up INA-5 (Manufactured by Sanyo Chemical Co., Ltd.) 5 g / L sodium carbonate 2 g / L pH 11 Bath ratio 1:40 Temperature 80 ° C. Time 20 minutes Regarding the obtained dyed fabric, the color clarity and coloring were evaluated as ◎,
△, Δ, × were evaluated. The washing fastness is JIS L-
The contamination was evaluated with 9 fibers by the 0844 A-2 method, and the light fastness was evaluated according to JIS L-0842.

Example 1 Using fabrics a, b, c and d, a dye having a sulfatoethylsulfone group and a monochlorotriazine group (Sumif
ixSupra Blue BRF Sumitomo Chemical Co., Ltd.
(Manufactured by Co., Ltd.). Then, the fabric is subjected to a soaping treatment and dyed fabrics 1 (a), 2 (b), 3
(C) and 4 (d) were obtained. The resulting fabric was evaluated for color development, washing fastness, and light fastness. The results are shown in Table 1.

Example 2 Using fabric a, a dye having a vinyl sulfone group and a monofluorotriazine group (Cibacron Blue F)
NR Ciba Specialty Chemicals Co., Ltd.). Then, soaping was performed to obtain a dyed fabric 5. The color development, washing fastness, and light fastness of the obtained fabric were evaluated, and the results are shown in Table 1.

Example 3 Using fabric a, a dye having a sulfatoethylsulfone group and a monochlorotriazine group (SumifixSupr)
a Blue BRF (manufactured by Sumitomo Chemical Co., Ltd.) using staining method 1. Next, a 50 g / L aqueous solution of sodium trichloroacetate was squeezed by a pad method at a pickup rate of 65%, and treated at 102 ° C. for 20 minutes using a normal pressure steamer. Further, a soaping treatment was performed to obtain a dyed fabric 6. The color development, washing fastness, and light fastness of the obtained fabric were evaluated, and the results are shown in Table 1.

Example 4 Using fabric a, a dye having a sulfatoethyl sulfone group and a monochlorotriazine group (SumifixSupr)
a Blue BRF (manufactured by Sumitomo Chemical Co., Ltd.) using staining method 1. Then, 50 g / L aqueous solution of sodium trichloroacetate and 50 g / L of sodium sulfate
The aqueous solution was squeezed by a pad method at a pickup rate of 65%, and treated at 102 ° C. for 20 minutes using a normal pressure steamer. Further, a soaping treatment was performed to obtain a dyed fabric 7. The resulting fabric was evaluated for color development, washing fastness, and light fastness.
It was shown to.

Example 5 Using fabric a, a dye having a sulfatoethylsulfone group and a monochlorotriazine group (SumifixSupr)
a Blue BRF (manufactured by Sumitomo Chemical Co., Ltd.) using staining method 1. Then, a 50 g / L aqueous solution of sodium trichloroacetate and a 20 g / L aqueous solution of sodium di-2-ethylhexyl sulfosuccinate were squeezed by a pad method at a pickup rate of 65%, and treated at 102 ° C. for 20 minutes using a normal pressure steamer. Further, a soaping treatment was performed to obtain a dyed fabric 8. The color development, washing fastness, and light fastness of the obtained fabric were evaluated, and the results are shown in Table 1.

Comparative Example 1 Using fabrics a, b, c and d, milling acid dye (Kay)
anol milling Ultra Sky SE
(Nippon Kayaku Co., Ltd.) using staining method 1. Further, a fixation process is performed to dye the fabric 9 (a),
10 (b), 11 (c) and 12 (d) were obtained. The color development, washing fastness, and light fastness of the obtained fabric were evaluated, and the results are shown in Table 1.

Comparative Example 2 Using fabrics a, b and c, a metal complex hydrochloric acid dye (Irgal
and Blue 3GL (manufactured by Ciba Specialty Chemicals) using staining method 1. Next, a fixing process is performed to dye the fabrics 13 (a) and 14 (a).
(B) and 15 (c) were obtained. The color development, washing fastness, and light fastness of the obtained fabric were evaluated, and the results are shown in Table 1.

From the results, it can be seen that the dyed fabric according to the present invention is excellent in sharpness, coloring, and wet fastness. In addition, there is no significant difference from the acid dye at the single yarn fineness of 2 deniers, and the fibers of 1 denier or less are superior to the conventional method. In particular, when applied to a fabric containing a high amino terminal fiber, an improvement in color development was observed while maintaining fastness.

Example 6 Using fabric a, a dye having a sulfatoethylsulfone group and a monochlorotriazine group (SumifixSupr)
a Blue BRF (manufactured by Sumitomo Chemical Co., Ltd.)
Staining was performed by Staining method 2. Next, a soaping treatment was performed to obtain a dyed fabric 16. The color development, washing fastness, and light fastness of the obtained fabric were evaluated, and the results are shown in Table 2.

COMPARATIVE EXAMPLE 3 Using a fabric a, a milling acid dye (Kayaanol®) was used.
Staining was performed by staining method 2 using illing Ultra Sky SE (manufactured by Nippon Kayaku Co., Ltd.). Further, a fixing treatment was performed to obtain a dyed fabric 17. The color development, washing fastness, and light fastness of the obtained fabric were evaluated, and the results are shown in Table 2.

From these results, it can be seen that the method of the present invention gives a dyed product having a clear hue as well as wet fastness and light fastness, in addition to dip dyeing and padding dyeing and printing.

[0039]

[Table 1]

[Table 2]

[0040]

According to the present invention, it is possible to provide an ultrafine polyamide fiber structure which achieves sufficient color developability and wet fastness and can express a clear hue. In particular, the present invention enables not only a deep color expression mainly composed of black but also a vivid dark color, and it is possible to provide a dyed article suitable particularly in the field of clothing.

Claims (11)

[Claims] (1) When dyeing a polyamide-based fiber structure having a single-fiber fineness of 0.0001 to 1 denier, it is dyed with a dye solution adjusted to pH 3 to 8 containing a reactive dye. A method for dyeing a polyamide-based fiber structure. 2. The method according to claim 1, wherein the reactive dye is at least one selected from the group consisting of a vinylsulfone group or a vinylsulfone group, a monohalogenated triazine group, a bromoacrylamide group, a carboxypyridiniotriazine group and a fluorochloropyrimidine group. The method for dyeing an ultrafine polyamide-based fiber structure according to claim 1, which has: 3. The reactive dye has at least one selected from a monohalogenated triazine group, a bromoacrylamide group, a carboxypyridiniotriazine group and a fluorochloropyrimidine group, and at least a vinylsulfone group or a vinylsulfone group. 3. The method for dyeing an ultrafine polyamide fiber structure according to claim 2, wherein the method has a reactive group that forms a group. 4. The dyeing method according to claim 1, wherein at least one selected from a pH slide agent and a weak alkali generator which shifts the pH to 8 to 13 at 60 ° C. or more after dyeing. A method for dyeing an ultrafine polyamide fiber structure, wherein the method is applied at a pH of 3 to 12, followed by a wet heat treatment. 5. The method for dyeing an ultrafine polyamide fiber structure according to claim 4, wherein the inorganic salt is imparted with 0.5 to 20% owf after dyeing, and then subjected to a wet heat treatment. 6. The dyeing method according to claim 4, wherein after the dyeing, an anionic surfactant is added in an amount of 0.5 to 20% o.
A method for dyeing an ultrafine polyamide-based fiber structure, comprising applying wf and then performing a wet heat treatment. 7. The anionic surfactant according to claim 6, wherein
A dyeing method for an ultrafine polyamide fiber structure, which is a sulfosuccinic acid diester type surfactant. 8. The method for dyeing an ultrafine polyamide fiber structure according to claim 1, wherein a soaping treatment is further performed at pH 6 to 13 after the dyeing. 9. The method for dyeing an ultrafine polyamide-based fiber structure according to claim 4, wherein a soaping treatment is further performed at a pH of 6 to 13 after performing a wet heat treatment. 10. A dyed product obtained by the dyeing method according to claim 1. 11. A polyamide fiber structure having a single fiber fineness of 0.0001 to 1 denier is dyed with a reactive dye, and has a washing fastness of 3rd grade or more specified in JIS L-0844 and JIS. An ultrafine polyamide fiber dyed product having a light fastness defined by L-0842 of 3 or higher.