JP2000073283A - Dyeing of polyester/polyamide mixed fiber structure and its dyed product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dyed product excellent in washing fastness by dyeing a polyester/polyamide mixed ultrafine fiber structure by using a disperse dye and a specific reactive dye under a specified pH condition. SOLUTION: A mixed fiber structure of a polyester-based fiber and a polyamide-based fiber each composed of an ultrafine fiber having <=1 de single fiber size is subjected to a single-bath and one-step dyeing by using a disperse dye and a reactive dye containing at least one or more groups selected from bromoacrylamide group, a monochlorotriazine group, a monofluorotriazine group, a carboxypyridiniotriazine group and a fluorochloropyrimidine group within a region of pH 3-8, and the dyed product is subjected to a reduction cleaning treatment. In other procedure, the mixed fiber structure is dyed within the region of pH 7-12 with the disperse dye stable in an alkali, and further dyed with the reactive dye within the region of pH 3-8, and the dyed product is subjected to the reduction cleaning treatment the same as the before.

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 a mixed fiber structure comprising a polyester fiber and a polyamide fiber having excellent washing fastness and a dyed product thereof.

[0002]

2. Description of the Related Art To dye a polyester fiber and a polyamide fiber, a conventional polyester fiber is dyed with a disperse dye, then subjected to reduction washing, and then the polyamide fiber is dyed with an acid dye or a metal complex salt dye. A two-stage dyeing method of dyeing and applying a fix treatment has been performed.

[0003] However, this method has a problem that washing fastness and light fastness decrease, and this problem has not been sufficiently solved even at present. This is considered to be caused by the disperse dye contaminating the polyamide fiber. After dyeing the polyester fiber, even if the disperse dye exhausted to the polyamide fiber is removed by performing sufficient reduction washing, the disperse dye in the polyester fiber becomes polyamide type when dyeing the polyamide fiber in the next step. It is thought to be caused by contamination of fibers. In order to remove the stain on the polyamide side of the disperse dye, it is ideal to carry out reduction washing in the final dyeing step, but in this case, the acid dye and the metal complex dye dyed on the polyamide side are also removed. Sisters,
As a result, almost only the polyester side is dyed, and the color developability is reduced.

In order to improve the fastness, it is possible to improve the fastness by dyeing only one side of polyester fiber or polyamide fiber. For example, a method of dyeing with a disperse dye or an acid dye corresponds to this method. However, this method has a problem in that although the fastness is excellent, the color developability is poor and the color expression range is narrowed.

To solve these problems, Japanese Patent Laid-Open No. 7-7 / 1995
No. 0949 discloses a method of dyeing a carrier with a disperse dye, dyeing the disperse dye preferentially on the polyester side, performing alkali reduction washing at a low temperature, and then dyeing at a low temperature with a metal complex dye. This method can certainly reduce the contamination of the disperse dye on the polyamide side, but this method does not sufficiently solve the problem of fastness, and further requires the use of a carrier. There are also problems such as a long dyeing time for dyeing, and a dark hue due to the use of a metal complex dye.

In JP-A-4-65586, a disperse dye and a dye having a sodium sulfonic acid group having a reduction washing durability of 70% or more in the structure are dyed together in the same bath, and then reduced under acidic conditions. A method for cleaning is disclosed. It is known that the acid reduction washing can effectively remove the disperse dye dyed on the polyamide fiber side, and this method improves the robustness because it can be finally reduced and washed. However, the reduction cleaning described herein is an acidic reduction cleaning at a pH of about 3, and it is necessary to preliminarily investigate and select a dye having resistance to the acid cleaning from an acid dye, a direct dye and the like. Since the number of such resistant dyes is limited, the hue that can be actually expressed is limited. Further, there is also a problem that the acidic dye cannot be used in the alkali reduction washing generally performed on the polyester fiber because the acidic dye is dropped off.

In particular, in the case of ultrafine fibers of a polyamide fiber having a single fiber fineness of 1 denier or less, there is a problem that washing fastness is not sufficient when dyeing with an acid dye or a metal complex dye. There was a problem that the property was reduced.

[0008]

SUMMARY OF THE INVENTION In view of the background of the prior art, the present invention provides a method for dyeing a mixed fiber structure comprising a polyester fiber and a polyamide fiber having a sufficient color density and good fastness. And a dyed product thereof.

[0009]

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

That is, the present invention provides a method for dyeing a polyester / polyamide mixed fiber structure, which comprises dyeing a mixed fiber structure composed of polyester fibers and polyamide fibers with a disperse dye and a reactive dye.

Further, the present invention is a dyed product of a mixed fiber structure comprising a polyester fiber and a polyamide fiber obtained by the above dyeing method.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester fiber referred to in the present invention typically includes polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, etc., but is not limited thereto, and isophthalic acid is an acid component other than terephthalic acid. Acid, naphthalene-
Modified polyesters such as those obtained by copolymerizing various dicarboxylic acids such as 2,5-dicarboxylic acid and diols such as polyethylene glycol are also included. The polyamide fiber is not particularly limited as long as it has an amide bond in the main chain, and examples thereof include nylon 4, nylon 6, nylon 66, nylon 610, and the like, and modified polyamides based on these.

The mixed fiber structure which is the object of the present invention is mainly composed of the above-mentioned polyester fiber and polyamide fiber. For example, the mixed fiber, the mixed spinning, the weaving, the cross knitting or the polyester fiber and the polyamide are contained in a single yarn. The form is not limited as long as it is a composite yarn containing fibers and the like, woven fabric, knitted fabric,
Nonwoven fabrics, yarns and the like are included. In addition, various kinds of fibers such as polyurethane, acrylic, cellulose, wool, silk and the like may be contained.

In the present invention, the fineness of a single fiber is not particularly limited, but a particularly effective object for the prior art is preferably a single fiber after a part of polyester fiber or polyamide fiber is dissolved or split. A mixed fiber mainly composed of ultrafine fibers having a fineness of 0.001 denier or more and 1 denier or less, especially a single fiber fineness of polyamide fiber of 0.001 denier or more and 1 denier or less, preferably 0.001 denier or more and 0.5 denier or less. It consists of a structure. The method for producing these fibers is not particularly limited, and fibers obtained from core-sheath type composite fibers, sea-island type composite fibers, split fiber type composite fibers, and the like can be used.

The dyeing conditions for dyeing the mixed fiber structure composed of polyester fibers and polyamide fibers according to the present invention with a disperse dye and a reactive dye are not particularly limited. It is preferable because it is effective for improvement. This reduction washing can be performed even after dyeing with a reactive dye. For example, dyeing with a disperse dye followed by reduction washing, dyeing with a reactive dye, fixing or soaping, or dyeing with a disperse dye followed by reduction dyeing with a reactive dye, or dyeing with a reactive dye Then, a method of dyeing with a disperse dye and performing reduction washing, or a method of simultaneously mixing and mixing a disperse dye and a reactive dye and performing reduction washing, or a method of dyeing with a reactive dye and then dyeing with a disperse dye and performing reduction washing It can be done by the method. Among them, from the viewpoint of simplicity and cost reduction, a reactive dye and a disperse dye are simultaneously mixed, and a pH of 3 or more and less than 8;
Preferably pH 4 or more and 7 or less, more preferably pH
A method of performing one-step one-step dyeing with 4.5 or more and 6 or less and then performing reduction washing is preferable. If the pH is less than 3, the color fastness tends to decrease, and if the pH is 8 or more, the dyeing on the polyamide side becomes insufficient, and it becomes difficult to sufficiently express a deep color. The temperature at this time is preferably 100 ° C. to 140 ° C.,
It is more preferable to adopt a two-step heating program in which the temperature is raised after keeping at 80 to 100 ° C. for 5 to 40 minutes.

In the present invention, as a method for preventing a decrease in the strength of the polyamide side and further improving the robustness,
(A) pH 7 to less than 12, preferably pH 8 to 1
0.5 or less, more preferably 90 at pH 8 or more and 9 or less.
(B) pH 3 or more and less than 8, preferably pH 4 or more and 7 or less, more preferably pH 4 or more and 6 or less using a reactive dye at a temperature of from 0 to 140 ° C. The dyeing is preferably performed in combination with the step of dyeing at 110 ° C. The order of (A) and (B) is not particularly limited. For example, after performing (A) and performing reduction cleaning, a method of performing (B) and performing a fixing process or a soaping process, preferably a soaping process, A method of performing the reduction cleaning by performing (B) or a method of performing (B) and then performing the reduction cleaning by performing (A) is preferable. Here, if an acid component remains on the fabric before the step (A), color blur may occur. Therefore, in the present invention, it is preferable to perform the step (B) after performing the step (A). In the step (A), a pH of 7 or more means that the pH is constantly 7 or more during dyeing. If the pH exceeds 12, sufficient dyeing cannot be expected. Here, it is preferable to use an alkaline buffer. The alkali generator is not particularly limited, and a commercially available polyester alkali dyeing adjuster may be used. For example, SENKA buffers 85, 95, 105, 110 (manufactured by SENKA CORPORATION),
OLINAX (manufactured by Meisei Chemical Co., Ltd.), Nikka Salt PA
-85 (manufactured by Nichika Chemical Co., Ltd.) or the like can be used. In the step (B), if the pH is less than 3, the washing fastness decreases, and if the pH is 8 or more, a sufficient amount of dyeing cannot be expected. For such pH adjustment, an acid or buffer is appropriately prepared, and the acid or salt to be used can be used without any particular limitation. Acetic acid, formic acid, hydrochloric acid and the like can be used as the acid generator, and those prepared with acetic acid and sodium acetate can be used as the buffer.

In the present invention, a sequestering agent, a leveling agent, a fastness improver, a bath softener and the like can be appropriately used in addition to the pH adjuster. Particularly when the reactive dye contains a metal, it is preferable to use a sequestering agent. The sequestering agent can be used without any particular limitation. At this time, the pH of the staining solution is carefully selected.

The alkali-stable disperse dye referred to in the present invention is not particularly limited, and a stable disperse dye which is not hydrolyzed by alkali is selected. These dyes can be appropriately selected and used from disperse dyes recommended by dye manufacturers as a streamlined alkaline dyeing method. As a method of reduction cleaning, it can be performed by using a reducing agent such as hydrosulfite and thiourea dioxide in combination with a surfactant. Here, there are a method performed on an acidic side and a method performed on an alkali side.
Either method is not particularly limited, but it is preferable to appropriately use them depending on the order of dyeing. When removing the excess disperse dye on the polyester surface and the disperse dye contaminated on the polyamide side, acidic reduction washing is preferable, and when washing and removing the unfixed dye of the disperse dye and the reactive dye on the polyester surface, pH 8 or more and 14 or less. It is preferable to carry out reduction washing under alkaline conditions from the viewpoint of fastness. For example, a method of dyeing a reactive dye and a disperse dye in the same bath and reducing and washing, a method of dyeing with a disperse dye, then a method of dyeing with a reactive dye and reducing and washing, a method of dyeing with a reactive dye, and a method of dyeing with a disperse dye and reducing and washing In the case of the method, the above-mentioned alkali reduction washing is preferable.

The soaping treatment in the present invention refers to a treatment for removing unfixed reactive dyes or dyes which have been dyed with a weak binding force and are easily detached after dyeing. It is different from fix treatment in which the dye dyed by force is contained in the fiber and reduction washing in which the disperse dye is decomposed and removed. Such soaping treatment is preferably performed at pH 6 to 13, more preferably at pH 8 to
12, more preferably at a pH of 10 to 12, has the effect of removing the unfixed reactive dye well and improving the fastness. When the pH is lower than 6, the wet fastness is reduced, and when the pH is higher than 13, discoloration is liable to occur. It is preferable to appropriately add a surfactant or the like to the solution adjusted to the pH in the above-mentioned range in order to improve the cleaning effect. The surfactant is not particularly limited, and for example, an anionic surfactant, a nonionic surfactant, or a combination thereof can be used.

In the present invention, the polyamide fiber side is substantially dyed with a reactive dye. Japanese Patent Application Laid-Open No. 4-65886 discloses a dye capable of withstanding acid reduction washing, which is selected from acid dyes and direct dyes. Does not describe the reactive dye. In the present invention, by using a reactive dye, not only acidic reduction cleaning but also alkali reduction cleaning can be performed, and the hue that can be expressed can be expanded.

The reactive dye used in the present invention is a water-soluble anionic dye which generally has a reactive group having a covalent bond to a hydroxyl group or an amino group. For example, a monochlorotriazine group represented by the formula [I] (X =
Cl, Y = substituent), monofluorotriazine group (X =
F, Y = substituent), carboxypyridiniotriazine group (X = formula [II], Y = substituent), dichlorotriazine group (X = Y = Cl), vinyl sulfone group represented by formula [III] ( Z is -CH = CH _2), such as sulfatoethyl sulfone group (Z represents ^{_{-CH 2 CH 2 Z 1, Z}} 1 is -OS
A leaving group such as O ₃ H, —OCOCH ₃ , —OPO ₃ H ₂ , or —Cl); a fluorochloropyrimidine group or a trichloropyrimidine group represented by the formula [IV]; Is a dye having at least one reactive group such as a group, but is not limited thereto.
Those having a reactive group as described in "Dye Chemistry" (Shinsensha) can be used.

In the present invention, the dye is not particularly limited as long as it has one or more of these reactive groups.
A dye having two or more monochlorotriazine groups of the formula [I] in the molecule, or a monochlorotriazine group or monofluorotriazine group of the formula [I] and a sulfatoethyl sulfone group of the formula [III] in the same molecule Different reactive group type dyes may be used. For example, in formula [I], Y may include formula [III].

[0023]

Embedded image

Embedded image

Embedded image

Embedded image (In the formula [IV], X _{1 to} X ₃ represent Cl or F)

Embedded image Dyes having such a reactive group include, for example, Sum
ifix, Sumfix Supra, Remazo
1, Celmazol, Levafix, Procio
n, Cibacron, Basilen, Drimar
ene, Drimalan, Lanasol, Kaya
Cion, Mikacation, Kayaceron R
Eact, Verofix and the like can be used. Any of the reactive dyes can provide a dyed fabric having good washing fastness by the method of the present invention. In particular, the sulfatoethyl sulfone group represented by the formula [III] has a reactive group protected by a protecting group. In order to obtain a sufficient fixing amount with a dye having only these reactive groups,
It is necessary to remove the protecting group to activate the reactive group.
In order to completely remove these protecting groups, an alkali is often required, and when such a dye is used, deprotection is performed under an alkali pretreatment before dyeing or under a neutral to weakly acidic condition. It is necessary to select a dye to be used. In a preferred embodiment of the present invention, when a dye requiring alkali pretreatment is used, the dye is alkali-dyed with a disperse dye, and the reaction bath is activated by introducing such a reactive dye while the temperature of the dye bath is 100 ° C to 50 ° C. After the dyeing, the dyeing bath is adjusted to be weakly acidic or acidic and dyed.

In the present invention, in particular, a reactive dye having at least one of a bromoacrylamide group, a monochlorotriazine group, a monofluorotriazine group, a carboxypyridiniotriazine group and a fluorochloropyrimidine group, more preferably bromoacrylamide Group,
Monochlorotriazine group, monofluorotriazine group,
At least one of carboxypyridiniotriazine groups
A reactive dye having one or more dyes is preferable because it has more excellent color developability and can improve washing fastness and / or light fastness. If it has one or more of these reactive groups,
The other reactive group may be of a different functional group type from, for example, a vinyl sulfone group or a sulfatoethyl sulfone group.
As these dyes, commercially available ones can be appropriately used. For example, Sumix Supra dye (manufactured by Sumitomo Chemical Co., Ltd.), Cibacron dye (manufactured by Ciba Specialty Chemicals Co., Ltd.), Lanasol dye (Ciba Specialty Chemicals (manufactured by Sumitomo Chemical Co., Ltd.) Co., Ltd.), Proc
ion dye (manufactured by Mitsui BASF Dye Co., Ltd.), Kayac
ion dye (manufactured by Nippon Kayaku Co., Ltd.), Kayaceron
React dye (Nippon Kayaku Co., Ltd.), Basile
n dye (manufactured by Mitsui BASF), Drimalan
F dye (manufactured by Clariant), Drimarene
A dye (manufactured by Clariant Co., Ltd.) or the like can be used.

In the present invention, those dyes having better dyeing properties to polyamide fibers, light fastness, reduction washing resistance and the like are appropriately selected and used.

In the present invention, polyester fibers and polyamide fibers can be dyed in the same color as well as different colors. This is because it depends on the hue of the disperse dye and the reactive dye, and since the stain of the disperse dye to the polyamide system is very small, the different color effect can be sufficiently expressed. Therefore, according to the present invention, a different-color effect can be improved, and a different-color and multicolor cloth excellent in color can be obtained.

The dyed product of the present invention is a dyed product obtained by the dyeing method of the present invention.

According to the present invention, it is possible to obtain a dyed product of a mixed fiber structure of polyester fiber and polyamide fiber having good fastness and excellent color development. As a result, applications of these fibers are expanded, and this material can be developed in fields where development was difficult in terms of fastness and color development. In addition, it is possible to easily provide a new appearance by utilizing the different color effect.

[0029]

EXAMPLES The following fabrics, dyes and reducing detergents were used for dyeing. In addition, the obtained dyed product was evaluated for washing fastness (JIS L-0844 A-2 method, using 9 fibers) and light fastness (JIS L-0842 method). , ○, △,
X: thin). In addition,% owf shows weight% with respect to a cloth.

Fabric a: Polyester (75 denier 36 filaments) for warp Nylon 6 (70 denier 24 filaments) for weft Fabric b: Polyester (75 denier 36 filaments) for warp Polyester / nylon composite splitting filament (75 denier) for weft 36 filaments 16 divisions) Disperse dye Dye 1: Dianix Blue SPH (manufactured by Dystar) Reactive dye Dye 2: Cibacron Blue FN-R (manufactured by Ciba Specialty Chemicals Co., Ltd.) Dye 3: Procion Red H-EXL (Mitsui BASF Dye Co., Ltd.) Acid Dye Dye 4: Nylosan Blue N-GFL (Clariant Co.) Leveling Agent Leveling Agent 1: Eganal LMD-J (Dystar Co., Ltd.) Leveling Agent 2: Albegal B ( Bath Specialty Chemicals Co., Ltd.) Reduction washing conditions (treatment at 80 ° C. for 20 minutes) Alkaline reduction washing Hydrosulfite 5 g / L NaOH 2 g / L Sunmol RC-700 2 g / L (Nichika Chemical Co., Ltd.) Acid Reduction washing Rongalit C 5 g / L Acetic acid 2 g / L Demol N 2 g / L (manufactured by Kao Corporation) Alkaline soaping conditions (treatment at 80 ° C. for 20 minutes) Gran Up INA-5 2 g / L (manufactured by Sanyo Chemical Co., Ltd.) Sodium carbonate 2g / L Fix treatment Sunlife TA-50K 2% owf (Nika Chemical Co., Ltd.) Acetic acid 0.5g / L

Example 1 Dye 1 (1% owf) and leveling agent 1 (0.5%)
g / L), adjusted to pH 5 with acetic acid / sodium acetate, stained at 130 ° C. for 40 minutes, and washed with alkali reduction. Next, dye 2 (1% owf) and leveling agent 2 (2% o
The dyed fabric 1 was obtained by adjusting pH to 5 with acetic acid / sodium acetate using wf), dyeing at 98 ° C. for 40 minutes, and performing alkali soaping. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Example 2 A dyed fabric 2 was obtained by dyeing the fabric b in the same manner as in Example 1. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Example 3 Dye 1 (1% owf) and Dye 2 (1% ow)
f) using a leveling agent 1 (0.5 g / L) to adjust the pH to 5 with acetic acid / sodium acetate and dyeing at 130 ° C. for 40 minutes,
Then, alkali reduction washing was performed to obtain a dyed fabric 3. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Example 4 Using the fabric b, dyeing was performed in the same manner as in Example 3 to obtain a dyed fabric 4. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Example 5 Fabric a was dyed at 130 ° C. for 40 minutes by adjusting pH to 8.5 with Orinux AM-85 (manufactured by Meisei Chemical Co., Ltd.), and then dye 2 (1% owf) and Dyeing agent 2 (2% o
The dyed fabric 5 was obtained by adjusting the pH to 5 with acetic acid / sodium acetate using wf), dyeing at 98 ° C. for 40 minutes, and performing alkali reduction washing. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Example 6 Using the fabric a, dyeing was carried out in the same manner as in Example 1, and a dyed fabric 6 was obtained by changing the alkali reduction washing to the acid reduction washing. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Comparative Example 1 A dyed fabric 7 was obtained by dyeing from dye 2 to dye 4 by changing the alkaline soaping to fix treatment and then dyeing in the same manner as in Example 1. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Comparative Example 2 Using the fabric b, the dyeing was performed in the same manner as in the comparative example 1 to obtain a dyed fabric 8. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Comparative Example 3 Dyeing cloth 9 was obtained by dyeing in the same manner as in Example 3 except that dye 2 was replaced with dye 4. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

Comparative Example 4 Dyeing cloth 10 was obtained by dyeing in the same manner as in Example 4 except that dye 2 was replaced with dye 4. Washing fastness of this dyed fabric,
The light fastness and color development were evaluated, and the results are shown in Table 1.

Comparative Example 5 Dyeing fabric 11 was obtained by dyeing in the same manner as in Example 5 except that dye 2 was replaced with dye 4. Washing fastness of this dyed fabric,
The light fastness and color development were evaluated, and the results are shown in Table 1.

Example 7 Dyeing cloth 12 was obtained by dyeing in the same manner as in Example 1 except that dye 2 was replaced with dye 3. Washing fastness of this dyed fabric,
The light fastness and color development were evaluated, and the results are shown in Table 1.

Example 8 Using the fabric b, dye 2 was replaced with dye 3, and the rest was dyed in the same manner as in Example 5 to obtain a dyed fabric 13. Washing fastness, light fastness and color development of the dyed fabric were evaluated, and the results are shown in Table 1.

From the above results, it is possible to obtain a dyed fabric having good fastness and color developability according to the present invention and a single fiber fineness of 1%.
Those with denier or less have a greater effect. Also,
It can be seen that by changing the colors of the disperse dye and the reactive dye, different-color and multicolor expression is also possible.

[0045]

[Table 1]

[0046]

According to the present invention, it is possible to obtain a dyed product of a mixed fiber structure composed of a polyester fiber and a polyamide fiber having excellent washing fastness and color development.

Claims (8)

[Claims] 1. A method for dyeing a polyester / polyamide mixed fiber structure, comprising dyeing a mixed fiber structure comprising polyester fibers and polyamide fibers with a disperse dye and a reactive dye. 2. The dyeing method according to claim 1, wherein
A method for dyeing a polyester / polyamide mixed fiber structure, wherein one-step one-step dyeing of a reactive dye and a disperse dye is performed in less than 8 steps. 3. The dyeing method according to claim 1, wherein (A)
Dyeing a polyester / polyamide mixed fiber structure, comprising: a step of dyeing with a disperse dye which is stable to alkali at pH 7 or more and less than 12; and (B) a step of dyeing with a reactive dye at pH 3 or more and less than 8. Method. 4. The method of claim 3, wherein (A)
A method for dyeing a polyester / polyamide mixed fiber structure, comprising the steps of: 5. The reaction dye according to claim 1, wherein said reactive dye has at least one of a bromoacrylamide group, a monochlorotriazine group, a monofluorotriazine group, a carboxypyridiniotriazine group, and a fluorochloropyrimidine group. The method for dyeing a polyester / polyamide mixed fiber structure according to any one of the above. 6. A dyeing method for a polyester / polyamide mixed fiber structure according to any one of claims 1 to 5, wherein reduction washing is performed at a pH of 8 to 14 after the dyeing. 7. The polyester / polyester according to claim 1, wherein the polyester fiber or the polyamide fiber has a single fiber fineness of 1 denier or less.
A method for dyeing a polyamide mixed fiber structure. 8. A dyed product of a mixed fiber structure comprising a polyester fiber and a polyamide fiber obtained by the dyeing method according to any one of claims 1 to 7.