Preparation method and application of environment-friendly acidic color fixing agent

Abstract

The invention relates to the technical field of dyes, and discloses a preparation method and application of an environment-friendly acidic color fixing agent, the preparation method comprises the following steps: S1) carrying out sulfonation reaction on tetramethyl biphenyl, acetic anhydride and 98% concentrated sulfuric acid in a first reaction temperature range to obtain a sulfonation product; preparing an intermediate mixture containing a monosulfonic acid biphenyl derivative and a disulfonic acid biphenyl derivative; and S2) dropwise adding deionized water and a 37% formaldehyde solution into the stirred intermediate mixture, heating to a second reaction temperature range, and terminating the condensation reaction when the viscosity is controlled to reach a viscosity threshold range, thereby obtaining the environment-friendly acidic color fixing agent. The prepared acidic color fixing agent does not contain phenol and bisphenol substances, is green and environment-friendly, and can meet the REACH regulation and the limit requirements of OEKO-TEX100. According to the application of the environment-friendly acidic color fixing agent, the color fastness of a nylon fabric or a nylon / spandex fabric can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of dyes, and in particular to a preparation method of an environmentally friendly acidic color fixing agent and application thereof. Background Art

[0002] Acid dyes need to be dyed on nylon or nylon / spandex fabrics under acidic conditions. The amino groups at the ends of nylon or nylon / spandex fibers absorb cationic hydrogen ions. The anionic acid dyes adsorbed on the fabrics have poor wet fastness, and the acid dyes are easily shed during soap washing.

[0003] In the prior art, an acidic fixing agent is used to improve the wet treatment color fastness of acid dyes or acidic mordant dyes to nylon fabrics and nylon / spandex fabrics.

[0004] Currently on the market, some acidic color fixing agents are synthesized through phenolsulfonic acid, bisphenol S / F / A and formaldehyde under alkaline conditions; some acidic color fixing agents are synthesized by sulfonation of bisphenol S using acetic anhydride as solvent, and condensation reaction of the sulfonated bisphenol S and formaldehyde under strong acidic conditions.

[0005] The acidic fixing agents synthesized by the above methods all contain residual phenols and / or bisphenols, which makes it difficult to meet the REACH regulations and the OEKO-TEX100 limit requirements for phenol, bisphenol A, bisphenol F and bisphenol S. Summary of the invention

[0006] In view of the above problems, the first object of the present invention is to provide a method for preparing an environmentally friendly acidic color fixing agent, so as to solve the problem that the acidic color fixing agent in the prior art cannot meet the limit requirements of bisphenol and phenol of REACH regulations and OEKO-TEX100 due to containing phenols and / or bisphenols.

[0007] The second object of the present invention is to provide an application of an environmentally friendly acidic color fixing agent to improve the color fastness of nylon fabric or nylon / spandex fabric.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] A method for preparing an environmentally friendly acidic color fixing agent comprises the following steps:

[0010] S1) adding tetramethylbiphenyl and acetic anhydride to a reaction vessel respectively, raising the temperature, and then dropping 98% concentrated sulfuric acid, controlling the dropping speed so that the reaction temperature is controlled within the first reaction temperature range, and keeping the temperature after the dropping is completed. After the sulfonation reaction is completed, the acidity of the reaction system is detected to meet the requirements of the acidity threshold, thereby obtaining an intermediate mixture containing a monosulfonic acid biphenyl derivative and a disulfonic acid biphenyl derivative;

[0011] S2) adding deionized water to the stirred intermediate mixture, and controlling the temperature during the dropping process not to exceed 70° C., cooling to 60° C. after the deionized water is added, and then completing the dropwise addition of 37% formaldehyde solution within 45 minutes, and then heating to a second reaction temperature range, keeping the temperature, detecting the viscosity of the reaction system, when the viscosity reaches the viscosity threshold range, terminating the condensation reaction, and cooling to below 80° C., cooling to below 50° C. after adding diethylene glycol monobutyl ether, and then adding water to adjust the solid content, so as to obtain the environmentally friendly acidic color fixing agent.

[0012] Specifically, in step S1), the molar concentration ratio of tetramethylbiphenyl to concentrated sulfuric acid is 1:(1.2-2.1), the first reaction temperature is 100±5°C, and the insulation time is 3h;

[0013] The acidity threshold is 22-28 mgKOH / g.

[0014] Preferably, in step S1), the acidity threshold is 24-25 mgKOH / g.

[0015] Preferably, in the intermediate mixture of step S1), the mass ratio of the monosulfonic acid biphenyl derivative to the disulfonic acid biphenyl derivative is (1-1.5):1.

[0016] Specifically, in step S2), calculated by weight, the weight of the intermediate mixture is 50-70 parts, the weight of deionized water is 10-20 parts, the weight of 37% formaldehyde solution is 10-20 parts, and the weight of diethylene glycol monobutyl ether is 2-4 parts.

[0017] Preferably, in step S2), the second reaction temperature is 110-120° C., and the insulation time is 4-5 h.

[0018] Preferably, in step S2), the viscosity threshold is 8000-10000 cPs, and the solid content is adjusted to 60±5%.

[0019] Furthermore, the present invention proposes an application of an environmentally friendly acidic color fixing agent, wherein the acidic color fixing agent prepared by the preparation method of the environmentally friendly acidic color fixing agent described in the above claims is used for color fixing treatment of nylon fabric or nylon / spandex fabric after dyeing.

[0020] The above technical scheme of the present invention has the beneficial effects that: the preparation method of the environmentally friendly acidic color fixing agent uses tetramethyl biphenyl as a basic raw material for sulfonation, and obtains an acidic color fixing agent that does not contain phenol and bisphenol substances through a condensation reaction, and does not require purification after sulfonation. The process is simple, energy consumption is low, and wastewater is less, which can reduce manufacturing costs, is green and environmentally friendly, and can meet the environmental protection requirements of REACH regulations and OEKO-TEX100.

[0021] Furthermore, the application of the environmentally friendly acidic color fixing agent proposed in the present invention improves the color fastness of nylon fabric or nylon / spandex fabric by using the prepared acidic color fixing agent for color fixing treatment after dyeing of nylon fabric or nylon / spandex fabric, and meets the environmental protection requirements of REACH regulations and OEKO-TEX100. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0023] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0024] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0025] A method for preparing an environmentally friendly acidic color fixing agent comprises the following steps:

[0026] S1) adding tetramethylbiphenyl and acetic anhydride to a reaction vessel respectively, raising the temperature, and then dropping 98% concentrated sulfuric acid, controlling the dropping speed so that the reaction temperature is controlled within the first reaction temperature range, and keeping the temperature after the dropping is completed. After the sulfonation reaction is completed, the acidity of the reaction system is detected to meet the requirements of the acidity threshold, thereby obtaining an intermediate mixture containing a monosulfonic acid biphenyl derivative and a disulfonic acid biphenyl derivative;

[0027] S2) adding deionized water to the stirred intermediate mixture, and controlling the temperature during the dropping process not to exceed 70° C., cooling to 60° C. after the deionized water is added, and then completing the dropwise addition of 37% formaldehyde solution within 45 minutes, and then heating to a second reaction temperature range, keeping the temperature, detecting the viscosity of the reaction system, when the viscosity reaches the viscosity threshold range, terminating the condensation reaction, and cooling to below 80° C., cooling to below 50° C. after adding diethylene glycol monobutyl ether, and then adding water to adjust the solid content, so as to obtain the environmentally friendly acidic color fixing agent.

[0028] The preparation method of the environmentally friendly acidic color fixing agent of the present invention uses tetramethyl biphenyl as a basic raw material and acetic anhydride as a solvent, and sulfonation is performed by adding concentrated sulfuric acid, and purification is not required after sulfonation, which can effectively reduce the manufacturing cost and reduce the discharge of sewage and energy consumption; and the acidic color fixing agent containing no phenol and bisphenol substances is prepared by adding formaldehyde solution for condensation reaction, which has the advantages of being green and environmentally friendly, and can meet the REACH regulations and the latest OEKO-TEX100 limit requirements for phenol, bisphenol A, bisphenol F and bisphenol S.

[0029] The molecular structure formula of the prepared environmentally friendly acidic color fixing agent is:

[0030]

[0031] The synthetic route of the environmentally friendly acidic color fixing agent of the present invention is as follows:

[0032]

[0033] Specifically, in step S1), the molar concentration ratio of tetramethylbiphenyl to concentrated sulfuric acid is 1:(1.2-2.1), the first reaction temperature is 100±5°C, and the insulation time is 3h;

[0034] The acidity threshold is 22-28 mgKOH / g.

[0035] The unit of the acidity threshold, mgKOH / g, represents the number of milligrams of potassium hydroxide required to neutralize 1 g of the reaction solution.

[0036] The method for preparing the environmentally friendly acidic color fixing agent of the present invention controls the ratio of the monosulfonic acid biphenyl derivative and the disulfonic acid biphenyl derivative in the sulfonation reaction product by controlling the molar concentration ratio of tetramethylbiphenyl to concentrated sulfuric acid, the acidity, the reaction temperature and the reaction time of the sulfonation reaction, so as to ensure the water solubility and color fixing effect of the prepared acidic color fixing agent.

[0037] Preferably, in step S1), the acidity threshold is 24-25 mgKOH / g.

[0038] The acidity threshold is 24-25 mgKOH / g, which can make the color fixing effect of the prepared acidic color fixing agent better.

[0039] Preferably, in the intermediate mixture of step S1), the mass ratio of the monosulfonic acid biphenyl derivative to the disulfonic acid biphenyl derivative is (1-1.5):1.

[0040] The mass ratio of the monosulfonic acid biphenyl derivative and the disulfonic acid biphenyl derivative is controlled to be (1-1.5):1 to ensure the color fixing effect of the prepared acidic color fixing agent.

[0041] Specifically, in step S2), calculated by weight, the weight of the intermediate mixture is 50-70 parts, the weight of deionized water is 10-20 parts, the weight of 37% formaldehyde solution is 10-20 parts, and the weight of diethylene glycol monobutyl ether is 2-4 parts.

[0042] Preferably, in step S2), the second reaction temperature is 110-120° C., and the insulation time is 4-5 h.

[0043] The second reaction temperature is controlled at 110-120°C and kept warm to keep the condensation reaction stable.

[0044] Preferably, in step S2), the viscosity threshold is 8000-10000 cPs, and the solid content is adjusted to 60±5%.

[0045] The viscosity of the reaction system is controlled at 8000-10000 cPs to prevent the viscosity of the reaction system from being too high and entering a gel state.

[0046] Furthermore, the present invention proposes an application of an environmentally friendly acidic color fixing agent, wherein the acidic color fixing agent prepared by the preparation method of the environmentally friendly acidic color fixing agent described in the above claims is used for color fixing treatment of nylon fabric or nylon / spandex fabric after dyeing.

[0047] The invention uses the prepared acidic color fixing agent for color fixing treatment of nylon fabric or nylon / spandex fabric after dyeing, so as to improve the color fastness of the nylon fabric or nylon / spandex fabric and meet the environmental protection requirements of REACH regulations and OEKO-TEX100.

[0048] Examples 1-3 and Comparative Examples

[0049] 1. Synthesis of the acidic color fixing agent of Example 1

[0050] 1.1 Synthesis of intermediate mixture

[0051] Put 210.3g of tetramethylbiphenyl into a four-necked flask, add 100g of acetic anhydride, raise the temperature to 95℃, slowly add 210g of 98% concentrated H2SO4, control the dropping speed to keep the temperature at about 100℃, start the insulation timer for 3 hours after the addition is completed, record the temperature every 30 minutes, and measure the acidity after sulfonation is completed. The acidity value is 27-28mgKOH / g.

[0052] 1.2 Synthesis of acidic fixing agent

[0053] 520.3 g of the intermediate mixture and 100 g of deionized water were slowly added to a 1000 ml four-necked reaction bottle. Heat was released during the addition process and the temperature was controlled not to exceed 70° C. After the addition, the temperature was lowered to 60° C., and 162.2 g of 37% formaldehyde solution was added dropwise within 30 minutes. The temperature was then raised to 110-120° C. and kept warm for 4.5 hours. The viscosity of the reaction system was tested. If the viscosity reached 8000-10000 cPs, the reaction was terminated, the temperature was lowered to below 80° C., 30 g of diethylene glycol monobutyl ether was slowly added, the temperature was lowered to below 50° C., water was added, and the solid content was adjusted to about 60%.

[0054] 2. Synthesis of Acidic Fixing Agent in Example 2

[0055] 2.1 Synthesis of intermediate mixture

[0056] Put 210.3g of tetramethylbiphenyl into a four-necked flask, add 100g of acetic anhydride, raise the temperature to 95°C, slowly add 120g of 98% concentrated H2SO4, control the dropping speed, and control the temperature at about 100°C. After the addition is completed, start the insulation timer for 3 hours, and record the temperature every 30 minutes; after the sulfonation is completed, measure the acidity, which is 22-23mgKOH / g.

[0057] 2.2 Synthesis of acidic fixing agent

[0058] 430.3 g of the intermediate mixture and 50 g of deionized water were slowly added to a 1000 ml four-necked reaction bottle. Heat was released during the addition process and the temperature was controlled not to exceed 70° C. After completion, the temperature was lowered to 60° C. 121.6 g of 37% formaldehyde solution was added dropwise within 30 minutes. The temperature was raised to 110-120° C. and kept warm for 4.5 hours. The viscosity of the reaction system was tested. If the viscosity reached 8000-10000 cPs, the reaction was terminated, the temperature was lowered to below 80° C., 30 g of diethylene glycol monobutyl ether was slowly added, and the temperature was lowered to below 50° C. Water was added to adjust the solid content to about 60%.

[0059] 3. Synthesis of Acidic Fixing Agent in Example 3

[0060] 3.1 Synthesis of intermediate mixture

[0061] Put 210.3g of tetramethylbiphenyl into a four-necked flask, add 100g of acetic anhydride, heat to 95℃, slowly add 170g of 98% concentrated H2SO4, control the dropping speed to keep the temperature at about 100℃, start the insulation timer for 3 hours after the addition is completed, and record the temperature every 30 minutes; after the sulfonation is completed, measure the acidity, the acidity value is 24-25mgKOH / g.

[0062] 3.2 Synthesis of acidic fixing agent

[0063] 480.3 g of the intermediate mixture and 100 g of deionized water were slowly added to a 1000 ml four-necked reaction bottle. Heat was released during the addition process and the temperature was controlled not to exceed 70°C. The temperature was lowered to 60°C and 137.8 g of 37% formaldehyde solution was added dropwise within 30 minutes. The temperature was raised to 110-120°C and kept warm for 4.5 hours. The viscosity of the reaction system was tested. If the viscosity reached 8000-10000 cPs, the reaction was terminated, the temperature was lowered to below 80°C, 30 g of diethylene glycol monobutyl ether was slowly added, the temperature was lowered to below 50°C, water was added, and the solid content was adjusted to about 60%.

[0064] 4. Synthesis of Bisphenol S Fixing Agent of Comparative Example

[0065] 250g of bisphenol S was added to a four-necked flask, and 100g of acetic anhydride was added. The temperature was raised to 110°C, and after dissolution, 80g of 98% concentrated sulfuric acid was added. The temperature was raised to 130°C with stirring and kept warm for 2h for sulfonation reaction. After the sulfonation was completed, the temperature was lowered to 100°C, 100g of water and 150g of 37% formaldehyde were added, and the temperature was kept warm for 4.5 hours. After the reaction was completed, the temperature was lowered to 80°C, and water was added to adjust the solid content to about 60%, thereby obtaining a bisphenol S color fixing agent of the comparative example.

[0066] 5. Application test of the color fixing agent of Examples 1-3 and Comparative Examples

[0067] 5.1 Test fabrics: nylon fabric and nylon / spandex fabric

[0068] 5.2 Several nylon fabrics and nylon / spandex fabrics were dyed with the following dyes respectively:

[0069] 5.21 Blue dyeing treatment

[0070] C-RL acid brilliant blue 2.0% (owf), glacial acetic acid 0.5g / L, bath ratio 1:10, dyeing treatment at 100℃ for 40min.

[0071] 5.22 Red dyeing treatment

[0072] FGS acid scarlet 2.0% (owf), glacial acetic acid 0.5 g / L, bath ratio 1:10, dyeing treatment at 100°C for 40 min.

[0073] 5.23 Black dyeing treatment

[0074] MLD115 acid black 4.0% (owf), A4RL acid yellow 0.5%, A2BL acid red 0.4%, glacial acetic acid 0.5g / L, bath ratio 1:10, dyeing treatment at 100℃ for 40min.

[0075] 5.24 Color Fixing Process

[0076] The nylon fabric and nylon / spandex fabric dyed in steps 4.21, 4.22 and 4.23 were respectively subjected to color fixing treatment using the following fixing agents:

[0077] Color fixing agent: 4.0% (owf) of the color fixing agent prepared in Example 1, Example 2, Example 3 or the comparative example,

[0078] Use 1.0g / L glacial acetic acid, bath ratio 1:15, and fix the color at 75℃ for 25 minutes. After fixation, wash with clean water without soap.

[0079] 5.25 The soap color fastness of the fabrics treated with the above color fixation treatments was tested in accordance with GB / T3921-2008C. The test results are shown in Table 1.

[0080] 5.26 The fabrics treated with the above color fixation were soaked in a 2g / L household laundry detergent aqueous solution at 95°C for 5 minutes, then naturally cooled to room temperature. The color change of the aqueous solution before and after soaking was visually observed to evaluate the water fastness. The test results are shown in Table 1.

[0081] 5.27 The color fastness to alkali perspiration of the fabrics treated with the above color fixation treatments was tested in accordance with GB / T3922-2013. The test results are shown in Table 2.

[0082] Table 1 Test results of soap color fastness and water blister fastness of Examples 1-3 and Comparative Examples

[0083]

[0084]

[0085] Table 2 Test results of alkali perspiration color fastness of Examples 1-3

[0086]

[0087]

[0088] From the test results of Table 1 and Table 2, it can be seen that the color fixing agent of Example 1 has good soap fastness and water blister fastness for nylon and nylon / spandex fabrics, and the color fixing effect on nylon fabric is better than that on nylon / spandex fabric; the color fixing agent of Example 1 greatly improves the alkali perspiration fastness of nylon or nylon / spandex fabrics, which can reach level 4 or above.

[0089] The color fixing agent of Example 2 has good soap fastness and blister fastness for nylon and nylon / spandex fabrics, and its color fixing effect on nylon fabric is better than that on nylon / spandex fabric; the color fixing agent of Example 2 greatly improves the alkali sweat fastness of nylon or nylon / spandex fabrics, which can reach level 3-4 or above, but the overall color fixing effect is worse than that of the color fixing agent of Example 1.

[0090] The color fixing agent of Example 3 has good soap fastness and blister fastness for nylon and nylon / spandex fabrics, and has a better color fixing effect on nylon fabrics than nylon / spandex fabrics; the color fixing agent of Example 3 greatly improves the alkali sweat fastness of nylon or nylon / spandex fabrics, which can reach level 4 or above, and has a slightly improved color fixing effect than the color fixing agent of Example 1.

[0091] The acidic color fixing agents prepared in the three embodiments have greatly improved the soap fastness, blister fastness and alkali perspiration color fastness of nylon and nylon / spandex fabrics, and the color fixing effect on nylon fabrics is better than that on nylon / spandex fabrics; compared with the bisphenol S type color fixing agent prepared in the comparative example, the color fixing agent prepared in the present invention has significantly improved the soap fastness, blister fastness and alkali perspiration color fastness of nylon and nylon / spandex fabrics, and the acidic color fixing agent prepared in the present invention does not contain phenol and bisphenol substances, and is an environmentally friendly acidic color fixing agent.

[0092] The acidic color fixing agents synthesized in Examples 1-3 of the present invention do not contain phenolic and bisphenolic substances, and the color change of nylon or nylon / spandex dyed fabrics is small. The soap washing fastness of Examples 1 and 3 can reach level 4-5, especially the alkali sweat fastness of Examples 1 and 3 can reach level 4 or above, which can completely replace the acidic color fixing agents currently on the market.

[0093] In summary, the preparation method of the environmentally friendly acidic color fixing agent uses tetramethyl biphenyl as a basic raw material for sulfonation, and obtains an acidic color fixing agent that does not contain phenol and bisphenol substances through a condensation reaction, and does not require purification after sulfonation. The process is simple, energy consumption is low, and wastewater is less, which can reduce manufacturing costs. It is green and environmentally friendly and can meet the environmental protection requirements of REACH regulations and OEKO-TEX100.

[0094] Furthermore, the application of the environmentally friendly acidic color fixing agent proposed in the present invention improves the color fastness of nylon fabric or nylon / spandex fabric by using the prepared acidic color fixing agent for color fixing treatment after dyeing of nylon fabric or nylon / spandex fabric, and meets the environmental protection requirements of REACH regulations and OEKO-TEX100.

[0095] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the scope of protection of the present invention.

Claims

1. A method for preparing an environmentally friendly acidic color fixing agent, characterized in that: The following steps are involved: S1) adding tetramethylbiphenyl and acetic anhydride to a reaction vessel respectively, raising the temperature, and then dropping 98% concentrated sulfuric acid, controlling the dropping speed so that the reaction temperature is controlled within the first reaction temperature range, and keeping the temperature after the dropping is completed. After the sulfonation reaction is completed, the acidity of the reaction system is detected to meet the requirements of the acidity threshold, thereby obtaining an intermediate mixture containing a monosulfonic acid biphenyl derivative and a disulfonic acid biphenyl derivative; S2) adding deionized water to the stirred intermediate mixture, and controlling the temperature during the dropping process not to exceed 70° C., cooling to 60° C. after the deionized water is added, and then completing the dropwise addition of 37% formaldehyde solution within 45 minutes, and then heating to a second reaction temperature range, keeping the temperature, detecting the viscosity of the reaction system, when the viscosity reaches the viscosity threshold range, terminating the condensation reaction, and cooling to below 80° C., cooling to below 50° C. after adding diethylene glycol monobutyl ether, and then adding water to adjust the solid content, so as to obtain the environmentally friendly acidic color fixing agent.

2. The method for preparing the environmentally friendly acidic color fixing agent according to claim 1, characterized in that: In step S1), the molar concentration ratio of tetramethylbiphenyl to concentrated sulfuric acid is 1:(1.2-2.1), the first reaction temperature is 100±5°C, and the insulation time is 3h; The acidity threshold is 22-28 mgKOH / g.

3. The method for preparing the environmentally friendly acidic color fixing agent according to claim 2, characterized in that: In step S1), the acidity threshold is 24-25 mgKOH / g.

4. The method for preparing the environmentally friendly acidic color fixing agent according to claim 1, characterized in that: In the intermediate mixture of step S1), the mass ratio of the monosulfonic acid biphenyl derivative to the disulfonic acid biphenyl derivative is (1-1.5):

1.

5. The method for preparing the environmentally friendly acidic color fixing agent according to claim 1, characterized in that: In step S2), calculated by weight, the weight of the intermediate mixture is 50-70 parts, the weight of deionized water is 10-20 parts, the weight of 37% formaldehyde solution is 10-20 parts, and the weight of diethylene glycol monobutyl ether is 2-4 parts.

6. The method for preparing the environmentally friendly acidic color fixing agent according to claim 1, characterized in that: In step S2), the second reaction temperature is 110-120° C. and the insulation time is 4-5 h.

7. The method for preparing the environmentally friendly acidic color fixing agent according to claim 1, characterized in that: In step S2), the viscosity threshold is 8000-10000 cPs, and the solid content is adjusted to 60±5%.

8. An application of an environmentally friendly acidic color fixing agent, characterized in that: The acidic color fixing agent prepared by the preparation method of the environmentally friendly acidic color fixing agent according to any one of claims 1 to 7 is used for color fixing treatment of nylon fabric or nylon / spandex fabric after dyeing.

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