A dyeing solution and dyeing method for p-aramid

Abstract

The application provides a dyeing solution and a dyeing method for para-aramid. The dyeing solution comprises polyester paste, ethylene glycol phenyl ether, dye mother liquor, pH regulator and solvent. The dyeing solution is most favorable for dyeing under the synergistic effect of ethylene glycol phenyl ether, polyester paste powder and sodium carbonate, and the dyeing effect gradually improves with the increase of the ratio of the three. The dyeing method specifically comprises the following steps: soaking para-aramid fibers in water, adding polyester paste and pH regulator, then performing temperature raising and holding treatment, then adding ethylene glycol phenyl ether for treatment, and finally adding dye mother liquor for dyeing. The method can efficiently utilize the carrier, reduce the carrier dosage, and ensure the fiber dyeing effect. After the dyeing depth is improved, the excellent sunlight resistance of the vat dye is utilized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fiber dyeing, in particular to a dyeing solution and a dyeing method for para-aramid fibers. BACKGROUND

[0002] Para-aramid is a kind of aramid fiber, full name poly-p-phenylene terephthalamide (PPTA), which has a rigid chain structure and an anti-form amide bond, and has high symmetry and regularity. Therefore, para-aramid has a comprehensive performance that other fibers cannot match, such as high strength, high modulus, and high temperature resistance, as well as excellent properties and functions such as wear resistance, flame resistance, chemical corrosion resistance, and dimensional stability, and is widely used in rubber, optical cable, protection, friction seal, composite material and other fields.

[0003] With the expansion of the production capacity of para-aramid fibers, para-aramid fiber products are increasingly used in civilian fields, and the product types are also increasingly diversified. The demand for color types of aramid products is also diverse, so the dyeing of para-aramid fibers has attracted attention. However, para-aramid fibers themselves are golden yellow, their molecular structure is tight, their crystallinity is high, their intermolecular force is strong, they are difficult to swell, their glass transition temperature is high, and they do not contain hydrophilic groups in their molecular structure. Therefore, it is very difficult to dye para-aramid fibers. Currently, different colors are mainly achieved by original liquid coloring and post-dyeing methods.

[0004] The original liquid coloring technology dyes para-aramid. Currently, color fibers are mainly produced by adding color master batches during spinning at home and abroad. The color fibers produced have uniform color and good color fastness, but the cost is high, the batch difference is large, and the color variety is limited. The post-dyeing of aramid mainly uses high-temperature and high-pressure dyeing of carriers, but the high-temperature and high-pressure dyeing of carriers improves the dyeing effect, but the carriers themselves mostly have irritating odor or are toxic, and the carrier emulsification is difficult, which leads to the space for improving the dyeing effect.

[0005] CN112359616A discloses a method for improving the sunlight fastness of aramid. First, a reducing dye suspension dyeing solution is prepared by stirring and mixing reducing dyes, urea, sulfur dioxide, ethylene glycol phenyl ether, dispersing agent and water in a predetermined concentration ratio; then the aramid fiber is put into the reducing dye suspension dyeing solution for dyeing treatment; then the dyed aramid fiber is put into a predetermined concentration sodium hydroxide water bath for reduction reaction to complete the reduction of the reducing dye; finally, the dyed aramid fiber is subjected to oxidation and soaping processes to prepare the dyed aramid fiber. Although the dyeing method can improve the sunlight fastness of aramid to level 4, the dyeing process is relatively complex, and it is difficult to complete the preparation of aramid products of various color types after reduction and oxidation after dyeing.

[0006] CN112359615A discloses a method for dyeing aromatic high-performance fibers, which is based on the traditional leuco acid dyeing method of reducing dyes with sodium hydroxide and sulfourea as reducing agents. Ammonium dihydrogen phosphate and a carrier are sequentially added to the leuco body solution of reducing dyes. Ammonium dihydrogen phosphate converts the leuco body of reducing dyes into leuco acid of reducing dyes and connects with urea in the dye solution through hydrogen bonds. The carrier connects with reducing dyes, phosphate and urea through hydrogen bonds respectively, forming a carrier-phosphate-urea combination and coating on the surface of leuco acid. Although the solar fastness of aramid can reach level 4 by using this dyeing method, the carrier used in this method is methyl formanilide or N,N-dimethylacetamide, so a high content is required to ensure the effect of fiber dyeing and the depth of dyeing.

[0007] Therefore, the present application is proposed. SUMMARY

[0008] One of the purposes of the present application is to provide a dyeing solution for para-aramid, characterized in that the dyeing solution for para-aramid comprises polyester paste, ethylene glycol phenyl ether, dye mother liquor, pH adjuster and solvent. The addition of polyester paste and ethylene glycol phenyl ether in the dyeing solution for para-aramid can efficiently utilize the carrier, reduce the amount of carrier, ensure the effect of fiber dyeing, improve the depth of dyeing, make good use of the excellent solar resistance of reducing dyes, and realize the production of solar-resistant color of para-aramid.

[0009] The second purpose of the present application is to provide the application of the dyeing solution for para-aramid in aramid fiber dyeing.

[0010] The third purpose of the present application is a dyeing method, which comprises soaking para-aramid in the above-mentioned dyeing solution for para-aramid to complete dyeing, so that the fiber is more easily dyed after the addition of dye mother liquor.

[0011] In order to achieve the above-mentioned purposes of the present application, the following technical solutions are adopted:

[0012] In the first aspect, the present application provides a dyeing solution for para-aramid, which comprises polyester paste, ethylene glycol phenyl ether, dye mother liquor, pH adjuster and solvent.

[0013] In the present application, the dyeing solution of the para-aramid fiber is added with polyester slurry, which has good adsorption capacity, and the pH regulator is a weak base, which can hydrolyze part of the ester bond in the molecular chain of the slurry, reducing the volume of the slurry molecular group in the solution. The dyeing solution is also added with ethylene glycol phenyl ether, which has a similar molecular structure. A large amount of ethylene glycol phenyl ether is gathered in the polyester slurry due to the molecular group, and the polyester slurry is easily adsorbed by the para-aramid fiber. That is, under the action of the circulating pump, ethylene glycol phenyl ether and polyester slurry can be distributed into the fiber aggregate, and the fiber surface is adsorbed with polyester slurry with high concentration, which is more conducive to opening the aggregate structure of the fiber surface layer and opening the channel for the subsequent dye mother liquor.

[0014] Preferably, the polyester slurry is polyethylene terephthalate.

[0015] In the present application, the polyethylene terephthalate structure in the polyester slurry molecule contains a benzene ring and an ester bond, and the molecular structure of the para-aramid fiber is similar to that of the polyester slurry, so it has good adsorption capacity.

[0016] Preferably, the molecular weight of the polyethylene terephthalate is 2×10 4 -3×10 4 g / mol, for example, it can be 2×10 4 g / mol, 2.2×10 4 g / mol, 2.4×10 4 g / mol, 2.6×10 4 g / mol, 2.8×10 4 g / mol, 3×10 4 g / mol, etc. The intrinsic viscosity of the polyethylene terephthalate is 0.5-0.7 dL / g, for example, it can be 0.5 dL / g, 0.55 dL / g, 0.6 dL / g, 0.65 dL / g, 0.7 dL / g, etc.

[0017] Preferably, the polyethylene terephthalate is a powdery polyethylene terephthalate.

[0018] Preferably, the particle size of the powdery polyethylene terephthalate is 60-80 mesh, for example, it can be 60 mesh, 65 mesh, 70 mesh, 75 mesh, 80 mesh, etc.

[0019] Preferably, in the dyeing solution of the para-aramid fiber, the mass percentage of the polyester slurry is 2-4%, for example, it can be 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, etc.

[0020] Preferably, the concentration of ethylene glycol phenyl ether in the dyeing solution of the para-aramid is 20-40 g / L, for example, it can be 20 g / L, 22 g / L, 24 g / L, 26 g / L, 28 g / L, 30 g / L, 32 g / L, 34 g / L, 36 g / L, 38 g / L, 40 g / L, etc.

[0021] Preferably, the dye mother liquor comprises a reducing dye and sodium hydroxide.

[0022] Preferably, the reducing dye is selected from any one or a combination of at least two of anthraquinone reducing dyes, indigoid reducing dyes, or fused ring reducing dyes.

[0023] Preferably, the concentration of the dye in the dye mother liquor is 20-60 g / L, for example, it can be 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, etc.

[0024] Preferably, the concentration of sodium hydroxide in the dye mother liquor is 20-60 g / L, for example, it can be 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, etc.

[0025] Preferably, the dye mother liquor further comprises a reducing agent.

[0026] Preferably, the reducing agent is selected from any one or a combination of at least two of sodium sulfide, sulfur dioxide hydride, or sodium sulfide.

[0027] Preferably, the concentration of the reducing agent in the dye mother liquor is 20-60 g / L, for example, it can be 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, etc.

[0028] Preferably, the pH adjuster is a weak alkaline pH adjuster.

[0029] Preferably, the weak alkaline pH adjuster is sodium carbonate.

[0030] Preferably, the concentration of the pH adjuster in the dyeing solution of the para-aramid is 1-3 g / L, for example, it can be 1 g / L, 1.5 g / L, 2 g / L, 2.5 g / L, 3 g / L, etc.

[0031] Preferably, the solvent is water.

[0032] In a second aspect, the present application provides a use of the dyeing solution of the para-aramid as described in the first aspect in dyeing aramid fibers.

[0033] In a third aspect, the present application provides a dyeing method, which comprises the following steps: soaking para-aramid fibers in the dyeing solution of the para-aramid fibers according to the first aspect to complete dyeing.

[0034] Preferably, the dyeing method specifically comprises the following steps:

[0035] (1) soaking para-aramid fibers in water, adding polyester paste and a pH adjuster, and then performing temperature raising and holding treatment;

[0036] (2) adding ethylene glycol phenyl ether to the mixed solution obtained in step (1) for treatment;

[0037] (3) adding a dye mother liquor to the mixed solution obtained in step (2) for dyeing; wherein the dye mother liquor comprises: a vat dye, a reducing agent, sodium hydroxide, and water.

[0038] Preferably, in step (1), the temperature raising rate is 1-3℃ / min, for example, it can be 1℃ / min, 1.2℃ / min, 1.4℃ / min, 1.6℃ / min, 1.8℃ / min, 2℃ / min, 2.2℃ / min, 2.4℃ / min, 2.6℃ / min, 2.8℃ / min, 3℃ / min, etc.

[0039] Preferably, in step (1), the holding temperature is 75-85℃, for example, it can be 75℃, 76℃, 78℃, 80℃, 82℃, 84℃, 85℃, etc.

[0040] Preferably, in step (1), the holding time is 5-15min, for example, it can be 5min, 6min, 8min, 10min, 12min, 15min, etc.

[0041] Preferably, in step (2), the treatment is performed by starting a circulating pump to run forward.

[0042] Preferably, in step (2), the forward running time is 5-12min, for example, it can be 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, etc.

[0043] Preferably, in step (3), the dyeing step specifically comprises the following steps: first, starting a circulating pump to run forward and reverse, and then performing temperature raising and holding treatment.

[0044] Preferably, the total time of forward and reverse running is 6-16min, for example, it can be 6min, 8min, 10min, 12min, 14min, 16min, etc.

[0045] Preferably, the ratio of the time required for the forward and reverse running is (3-5):1, for example, it can be 3:1, 3.5:1, 4:1, 4.5:1, 5:1, etc.

[0046] Preferably, the rate of temperature rise is 1-3℃ / min, for example, it can be 1℃ / min, 1.2℃ / min, 1.4℃ / min, 1.6℃ / min, 1.8℃ / min, 2℃ / min, 2.2℃ / min, 2.4℃ / min, 2.6℃ / min, 2.8℃ / min, 3℃ / min, etc.

[0047] Preferably, the temperature of the holding is 120-140℃, for example, it can be 120℃, 125℃, 130℃, 135℃, 140℃, etc.

[0048] Preferably, the time of the holding is 40-80min, for example, it can be 40min, 45min, 50min, 55min, 60min, 65min, 70min, 75min, 80min, etc.

[0049] As a preferred technical solution of the present application, the dye mother liquor is prepared by the following method:

[0050] Using dry cylinder reduction technology, according to the weight of the dye, weighing according to the bath ratio 1:(40-60) (for example, it can be 1:40, 1:45, 1:50, 1:55, 1:60, etc.), to prepare 10-30g / L (for example, it can be 10g / L, 15g / L, 20g / L, 25g / L, 30g / L, etc.) of the aqueous solution of the dye, then add sodium hydroxide (wherein the mass ratio of the dye and sodium hydroxide is 1:(0.8-1.2), for example, it can be 1:0.8, 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1, 1:1.2, etc.) and stir uniformly, then heat to 40-60℃ (for example, it can be 40℃, 45℃, 50℃, 55℃, 60℃, etc., according to the corresponding reduction temperature of the selected reducing dye), after the temperature reaches, finally add the reducing agent (wherein the mass ratio of the dye and the reducing agent is 1:(0.8-1.2), for example, it can be 1:0.8, 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1, 1:1.2, etc.) and stand for 5-10min (for example, it can be 5min, 6min, 7min, 8min, 9min, 10min, etc., according to the selected dye mother liquor), to prepare the dye mother liquor.

[0051] As a preferred technical solution of the present application, the method for improving the dyeing of para-aramid fiber, specifically comprising the following steps:

[0052] (1) Configuration of dye mother liquor: according to the weight of the dye, 10-30 g / L of the aqueous solution of the dye is prepared by weighing according to the bath ratio of 1:(40-60), then sodium hydroxide is added (wherein the mass ratio of the dye mother liquor and sodium hydroxide is 1:(0.8-1.2)), and stirred uniformly, then heated to 40-60℃, after the temperature reaches, finally add the reducing agent (wherein the mass ratio of the dye and the reducing agent is 1:(0.8-1.2)) and stand for 5-10 min, to prepare the dye mother liquor;

[0053] (2) Treatment and hydrolysis of polyester slurry: the para-aramid fiber is soaked in water with a bath ratio of 1:(10-50), 2-4wt% polyester slurry powder and 5-10g / L weak alkaline pH regulator are added, and the temperature is raised to 50-70℃ at a rate of 1-3℃ / min and kept for 5-15min;

[0054] (3) Ethylene glycol phenyl ether treatment: 20-40g / L of ethylene glycol phenyl ether is added to the above mixture and the circulating pump is started, and the forward rotation is operated for 5-12min;

[0055] (4) Complete dyeing: add the dye mother liquor to the above mixture, start the circulating pump, the forward rotation time is 3-5 times of the reverse rotation time, then raise the temperature to 120-140℃ at a rate of 1-3 / min, and keep for 40-80min to complete the dyeing of the para-aramid fiber.

[0056] Compared with the prior art, the present application has the following beneficial effects:

[0057] (1) The molecular structure of the added polyester slurry powder in the present application is ethylene terephthalate, which contains benzene ring and ester bond, and the molecular structure of para-aramid is similar to it, so it has good adsorption capacity, and the pH regulator is weak alkali, which can hydrolyze part of the ester bond in the slurry molecular chain, reducing the volume of the slurry molecular group in the solution;

[0058] (2) In the hydrolyzed polyester slurry solution of the present application, ethylene glycol phenyl ether is added, and the molecular structures of the two are similar. In the polyester slurry, a large amount of ethylene glycol phenyl ether is gathered in the molecular group, and the polyester slurry is easily adsorbed by para-aramid. Under the action of the circulating pump, ethylene glycol phenyl ether and polyester slurry can be distributed into the fiber aggregate, and the fiber surface adsorbs polyester slurry with high concentration, which is more conducive to opening the surface layer of the fiber aggregate structure, and opening the channel for the subsequent entry of the dye mother liquor;

[0059] (3) The dyeing method of the present application can efficiently utilize the carrier, reduce the amount of carrier, and ensure the effect of fiber dyeing. After the depth of dyeing is improved, the excellent light resistance of the reducing dye is utilized to realize the production of para-aramid light-resistant color;

[0060] (4) The color depth of the para-aramid fiber dyed by the dyeing method of the present application is 6-9, and the light fastness is 2-5. DETAILED DESCRIPTION

[0061] Unless otherwise defined, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear; however, in the event of any latent ambiguity, definitions provided herein take precedent over any dictionary or extrinsic definition. In this application, the use of "or" means "and / or" unless specifically stated otherwise, e.g., "comprising A or B" means "comprising A or B or both". Also, the use of "comprising" or "including" or "having" are not intended to be construed to imply exclusivity of the indicated element or method steps therefrom.

[0062] Generally, the nomenclature used in connection with, and the techniques of, cell and tissue culture, molecular biology, immunology, microbiology, genetics and protein and nucleic acid chemistry and hybridization described herein are those well-known and commonly used in the art. The methods and techniques of the present application are generally performed according to conventional methods well-known in the art and as described in various general and more specific references that are cited throughout the present specification unless otherwise indicated. Enzymatic reactions and purification techniques are performed according to the manufacturer's instructions, as commonly accomplished in the art or as described herein. The nomenclature used in connection with, and the techniques of, analytical chemistry, synthetic organic chemistry, and medicinal and pharmaceutical chemistry described herein are those well-known and commonly used in the art.

[0063] The technical solutions of the present application will be described clearly and completely in combination with the embodiments below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0064] The present application will be further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to the existing methods, or directly purchased from the market.

[0065] The sources of the following raw materials are shown as follows:

[0066] Name Manufacturer Model / specification

[0067] Polyester sizing powder DuPont Industrial grade / powder

[0068] Dye mother liquor Jiangsu Yabang Dyeing Co., Ltd. Commercial grade / powder

[0069] Example 1

[0070] The present embodiment provides a dyeing method of para-aramid fiber, which comprises the following steps:

[0071] (1) According to the weight of the dye, weigh 20 g / L of a solution with a bath ratio of 1:50, then add an equal amount of sodium hydroxide to the dye and stir until uniform, then heat to 50°C, and after the temperature reaches, finally add an equal amount of CH4N2O2S to the dye and stand for 8 min to prepare the dye mother liquor.

[0072] (2) According to the weight of the para-aramid fiber added, weigh 2% of polyester sizing powder, add a certain amount of water, then add 2% of polyester sizing powder, heat to 80°C at a rate of 2°C / min and keep for 10 min with a bath ratio of 1:20;

[0073] (3) Add 20 g / L of ethylene glycol phenyl ether and start the circulating pump, and run for 8 min;

[0074] (4) Add 3% of the dye mother liquor, start the circulating pump, and the ratio of forward rotation to reverse rotation is 4:1, the total time of forward rotation and reverse rotation is 10 min, then heat to 130°C at a rate of 2°C / min and keep for 60 min.

[0075] Example 2

[0076] The present example provides a dyeing method for para-aramid fibers, which is different from Example 1 only in that the amount of polyester sizing powder added is 3% and the amount of ethylene glycol phenyl ether added is 30 g / L, and the other steps are the same as those of Example 1.

[0077] Example 3

[0078] The present example provides a dyeing method for para-aramid fibers, which is different from Example 1 only in that the amount of polyester sizing powder added is 4% and the amount of ethylene glycol phenyl ether added is 40 g / L, and the other steps are the same as those of Example 1.

[0079] Example 4

[0080] The present example provides a dyeing method for para-aramid fibers, which comprises the following steps:

[0081] (1) According to the weight of the dye, weigh 20 g / L of a solution with a bath ratio of 1:50, then add an equal amount of sodium hydroxide to the dye and stir until uniform, then heat to 50°C, and after the temperature reaches, finally add an equal amount of CH4N2O2S to the dye and stand for 8 min to prepare the dye mother liquor.

[0082] (2) According to the weight of the para-aramid fiber added, weigh 2% of polyester sizing powder, add a certain amount of water, then add 2% of polyester sizing powder, 1 g / L of sodium carbonate, heat to 80°C at a rate of 2°C / min and keep for 10 min with a bath ratio of 1:20;

[0083] (3) Add 20 g / L of ethylene glycol phenyl ether and start the circulating pump, and run for 8 min;

[0084] (4) Add 3% of the dye mother liquor, start the circulating pump, the ratio of forward rotation to reverse rotation is 4:1, the total time of forward rotation and reverse rotation is 10 min, then increase to 130°C at a rate of 2°C / min and keep for 60 min.

[0085] Example 5

[0086] The present example provides a dyeing method of para-aramid, which is only different from example 4 in that the added amount of polyester sizing powder is 3%, the added amount of ethylene glycol phenyl ether is 30 g / L, the added amount of sodium carbonate is 2 g / L [the feeding amount of sodium carbonate in step (2)], and other steps are completely the same as example 4.

[0087] Example 6

[0088] The present example provides a dyeing method of para-aramid, which is only different from example 4 in that the added amount of polyester sizing powder is 4%, the added amount of ethylene glycol phenyl ether is 40 g / L, the added amount of sodium carbonate is 3 g / L [the feeding amount of sodium carbonate in step (2)], and other steps are completely the same as example 4.

[0089] Example 7

[0090] The present example provides a dyeing method of para-aramid, which comprises the following steps:

[0091] (1) According to the weight of the dye, weigh 20 g / L of solution with a bath ratio of 1:50, then add an equivalent amount of sodium hydroxide to the dye and stir uniformly, then heat to 50°C, after the temperature reaches, finally add an equivalent amount of CH4N2O2S to the dye and stand for 8 min, and prepare the dye mother liquor.

[0092] (2) According to the weight of the para-aramid fiber added, weigh 4% of polyester sizing powder, 3 g / L of sodium carbonate and 40 g / L of ethylene glycol phenyl ether with a bath ratio of 1:20, then heat to 80°C at a rate of 2°C / min and keep for 10 min, and start the circulating pump, forward rotation for 8 min;

[0093] (3) Add 3% of the dye mother liquor, start the circulating pump, the ratio of forward rotation to reverse rotation is 4:1, the total time of forward rotation and reverse rotation is 10 min, then increase to 130°C at a rate of 2°C / min and keep for 60 min.

[0094] Example 8

[0095] The present example provides a dyeing method of para-aramid, which comprises the following steps:

[0096] (1) According to the weight of the dye, a solution of 20 g / L is prepared according to the bath ratio of 1:50, then an equal amount of sodium hydroxide is added and stirred uniformly, heated to 50°C, after the temperature reaches, finally an equal amount of CH4N2O2S is added and placed for 8 min, then 4% of polyester sizing powder, 3 g / L of sodium carbonate and 40 g / L of ethylene glycol phenyl ether are added to prepare the dye mother liquor.

[0097] (2) According to the weight of the para-aramid fiber added, a certain amount of water is added according to the bath ratio of 1:20, then 3% of the above dye mother liquor is added, the circulating pump is started, the forward rotation and reverse rotation time ratio is 4:1, the total time of forward rotation and reverse rotation is 10 min, then it is raised to 130°C at a rate of 2°C / min and kept for 60 min.

[0098] Example 9

[0099] The example provides a para-aramid dyeing method, which is only different from example 6 in that the forward rotation and reverse rotation time ratio in step (4) is 3:1, then it is raised to 120°C at a rate of 1°C / min and kept for 80 min, and the other steps are exactly the same as example 6.

[0100] Example 10

[0101] The example provides a para-aramid dyeing method, which is only different from example 6 in that the forward rotation and reverse rotation time ratio in step (4) is 5:1, then it is raised to 140°C at a rate of 3°C / min and kept for 50 min, and the other steps are exactly the same as example 6.

[0102] Comparative Example 1

[0103] The comparative example provides a para-aramid dyeing method, which comprises the following steps:

[0104] (1) According to the weight of the dye, a solution of 20 g / L is prepared according to the bath ratio of 1:50, then an equal amount of sodium hydroxide is added and stirred uniformly, heated to 50°C, after the temperature reaches, finally an equal amount of CH4N2O2S is added and placed for 8 min, then 4% of polyester sizing powder, 3 g / L of sodium carbonate and 40 g / L of ethylene glycol phenyl ether are added to prepare the dye mother liquor.

[0105] (2) According to the weight of the para-aramid fiber added, a certain amount of water is added according to the bath ratio of 1:20, then it is raised to 80°C at a rate of 2°C / min and kept for 10 min;

[0106] (3) 20 g / L of ethylene glycol phenyl ether is added and the circulating pump is started, forward rotation for 8 min;

[0107] (3) Add 3% of the dye mother liquor, start the circulating pump, the ratio of forward rotation to reverse rotation is 4:1, the total time of forward rotation and reverse rotation is 10 min, then increase to 130°C at a rate of 2°C / min and keep for 60 min.

[0108] Comparative Example 2

[0109] This comparative example provides a dyeing method of para-aramid, which is different from Comparative Example 1 only in that in step (3), the addition amount of ethylene glycol phenyl ether is 30 g / L, and other steps are exactly the same as those of Comparative Example 1.

[0110] Comparative Example 3

[0111] This comparative example provides a dyeing method of para-aramid, which is different from Comparative Example 1 only in that in step (3), the addition amount of ethylene glycol phenyl ether is 40 g / L, and other steps are exactly the same as those of Comparative Example 1.

[0112] Comparative Example 4

[0113] This comparative example provides a dyeing method of para-aramid, which comprises the following steps:

[0114] (1) According to the weight of the dye, weigh 20 g / L of the solution with a bath ratio of 1:50, then add sodium hydroxide equivalent to the amount of the dye and stir uniformly, then heat to 50°C, after the temperature reaches, finally add CH4N2O2S equivalent to the amount of the dye and stand for 8 min, to prepare the dye mother liquor.

[0115] (2) According to the weight of the para-aramid fiber added, weigh 2% of the polyester sizing powder with a bath ratio of 1:20, then add a certain amount of water, then increase the temperature to 80°C at a rate of 2°C / min and keep for 10 min;

[0116] (3) Add 3% of the dye mother liquor, start the circulating pump, the ratio of forward rotation to reverse rotation is 4:1, the total time of forward rotation and reverse rotation is 10 min, then increase to 130°C at a rate of 2°C / min and keep for 60 min.

[0117] Comparative Example 5

[0118] This comparative example provides a dyeing method of para-aramid, which is different from Comparative Example 4 only in that in step (2), the addition amount of polyester sizing powder is 3%, and other steps are exactly the same as those of Comparative Example 4.

[0119] Comparative Example 6

[0120] This comparative example provides a dyeing method of para-aramid, which is different from Comparative Example 4 only in that in step (2), the addition amount of polyester sizing powder is 4%, and other steps are exactly the same as those of Comparative Example 4.

[0121] Comparative Example 7

[0122] The present comparative example provides a dyeing method of para-aramid, which comprises the following steps:

[0123] (1) According to the weight of the dye, weigh 1:50 of the bath ratio to prepare a solution of 20 g / L, then add an equivalent amount of sodium hydroxide and stir uniformly, then heat to 50°C, after the temperature reaches, finally add an equivalent amount of CH4N2O2S and stand for 8 min, to prepare a dye mother liquor.

[0124] (2) According to the weight of the para-aramid fiber added, weigh 1:20 of the bath ratio, add a certain amount of water, and heat to 80°C at a rate of 2°C / min and keep for 10 min;

[0125] (3) Add 3% of the dye mother liquor, start the circulating pump, the forward rotation time ratio is 4:1, and the total time of forward rotation and reverse rotation is 10 min, then increase to 130°C at a rate of 2°C / min, and keep for 60 min.

[0126] Comparative Example 8

[0127] The present example provides a dyeing method of para-aramid, which comprises the following steps:

[0128] (1) According to the weight of the dye, weigh 1:50 of the bath ratio to prepare a solution of 20 g / L, then add an equivalent amount of sodium hydroxide and stir uniformly, then heat to 50°C, after the temperature reaches, finally add an equivalent amount of CH4N2O2S and stand for 8 min, to prepare a dye mother liquor.

[0129] (2) According to the weight of the para-aramid fiber added, weigh 1:20 of the bath ratio, add a certain amount of water, then add 2% of polyester sizing powder, heat to 80°C at a rate of 2°C / min and keep for 10 min;

[0130] (3) Add 40 g / L of N,N-dimethylacetamide and start the circulating pump, forward rotation for 8 min;

[0131] (4) Add 3% of the dye mother liquor, start the circulating pump, the forward rotation time ratio is 4:1, and the total time of forward rotation and reverse rotation is 10 min, then increase to 130°C at a rate of 2°C / min, and keep for 60 min.

[0132] Comparative Example 9

[0133] The present comparative example provides a dyeing method of para-aramid, which is different from Example 1 only in that 2% of polyester sizing powder is replaced by 2% of urea, and the other steps are the same as Example 1.

[0134] Comparative Example 10

[0135] The present comparative example provides a dyeing method of para-aramid, which is only different from example 1 in that 20 g / L of ethylene glycol phenyl ether is replaced by 20 g / L of phenoxyisopropanol, and other steps are exactly the same as example 1.

[0136] Performance test

[0137] Test sample: para-aramid dyed by the dyeing method of examples 1-10 and para-aramid dyed by comparative examples 1-10;

[0138] Test item or method: (1) dyeing depth: colorimeter is used to test the dyeing depth; (2) light fastness: test conditions are ISO 105 B02:2014 or equivalent GB / T 8427:2008.

[0139] The specific test results are shown in Table 1 below:

[0140] Table 1

[0141] No. Color depth Fastness to daylight No. Color depth Fastness to daylight Example 1 6.5 2-3 Comparative Example 1 6.3 2 Example 2 7.3 3-4 Comparative Example 2 6.9 2-3 Example 3 7.5 3-4 Comparative Example 3 7.4 3-4 Example 4 7.7 3-4 Comparative Example 4 5.6 1-2 Example 5 7.9 4 Comparative Example 5 5.7 1-2 Example 6 8.4 4-5 Comparative Example 6 5.7 1-2 Example 7 7.7 3-4 Comparative Example 7 5.6 1-2 Example 8 7.6 3-4 Comparative Example 8 7.8 3-4 Example 9 8.6 4-5 Comparative Example 9 6.4 2 Example 10 9 4-5 Comparative Example 10 6.3 2

[0142] It can be seen from the test data in Table 1 that the color and light fastness of para-aramid fiber dyed by the preferred dyeing method of the present application can reach more than 3. The dyeing method of the present application can efficiently utilize the carrier, reduce the amount of carrier, and ensure the effect of fiber dyeing. After the depth of dyeing is improved, the excellent light resistance of the vat dye is used to realize the production of para-aramid light-resistant color.

[0143] The color depth and light fastness of the para-aramid fiber dyeing sample obtained by dyeing according to the methods of examples 1-6 are significantly improved, and the color depth and light fastness of example 6 are the most excellent, which indicates that the three synergistic effects of ethylene glycol phenyl ether, polyester sizing powder and sodium carbonate are most beneficial to dyeing, and the dyeing effect gradually improves with the increase of the proportion of the three.

[0144] And it can be seen from examples 1-6 compared with comparative examples 1-3 and comparative example 7 that ethylene glycol phenyl ether significantly improves the dyeing effect of para-aramid, and in the synergistic effect of polyester sizing powder and sodium carbonate, ethylene glycol phenyl ether can fully play the dyeing effect. And it can be seen from comparative examples 4-5 that only adding polyester sizing powder has almost no significant effect on dyeing; it can be seen from comparative example 8 that using a dyeing agent similar to the molecular structure of aramid is beneficial to improving the dyeing effect, and ethylene glycol phenyl ether is more similar to the molecular structure of para-aramid, that is, it is more beneficial to improving the dyeing effect.

[0145] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A dyeing method, characterized in that: The dyeing method specifically comprises the following steps: (1) Prepare dye mother liquor: According to the weight of the dye, weigh it at a bath ratio of 1:(40-60) to prepare a 10-30 g / L dye aqueous solution, then add sodium hydroxide and stir evenly, then heat to 40-60 ° C. After the temperature reaches 40-60 ° C, finally add the reducing agent and let it stand for 5-10 minutes to prepare the dye mother liquor; wherein, the mass ratio of the dye mother liquor to sodium hydroxide is 1:(0.8-1.2); the mass ratio of the dye to the reducing agent is 1:(0.8-1.2); (2) Treatment and hydrolysis of polyester slurry: para-aramid fiber is soaked in water at a bath ratio of 1:(10-50), 2-4 wt% polyester slurry powder and 5-10 g / L weak alkaline pH regulator are added, the temperature is raised to 50-70 °C at a rate of 1-3 °C / min and kept warm for 5-15 min; wherein the polyester slurry powder is polyethylene terephthalate; the weak alkaline pH regulator is sodium carbonate; the holding temperature is 75-85 °C; the molecular weight of the polyethylene terephthalate is 2×10 4 -3×10 4 g / mol, the intrinsic viscosity of the polyethylene terephthalate is 0.5-0.7 dL / g; (3) Treatment of ethylene glycol phenyl ether: Add 20-40 g / L of ethylene glycol phenyl ether to the mixed solution obtained in step (2) and start the circulation pump, running it for 5-12 minutes; (4) Complete dyeing: Add the dye mother liquor to the mixed solution obtained in step (3), start the circulation pump, and set the forward and reverse time ratio to (3-5):

1. Then, raise the temperature to 120-140°C at 1-3 / min and keep it warm for 40-80 min to complete the dyeing of the para-aramid fiber.

2. The dyeing method according to claim 1, wherein The particle size of the polyethylene terephthalate is 60-80 meshes.

3. The dyeing method according to claim 1, wherein The vat dye is selected from any one of anthraquinone vat dyes, indigoid vat dyes or condensed ring vat dyes, or a combination of at least two thereof.

4. The dyeing method according to claim 1, wherein The reducing agent is selected from any one of sodium hydrosulfite, thiourea dioxide or sodium sulfide, or a combination of at least two thereof.

5. The dyeing method according to claim 1, wherein The dyeing steps are specifically as follows: firstly starting the circulation pump to perform forward and reverse operation, and then performing heating and heat preservation treatment.

6. The dyeing method according to claim 1, wherein The total time of the forward operation and the reverse operation is 6-16 minutes.