Oxidized fiber / modacrylic flame resistant needle punch felt and cationic dye nonaqueous medium dyeing method

Abstract

This invention belongs to the field of dyeing technology, and specifically relates to a flame-retardant needle-punched felt made of oxidized fiber / acrylic chlorofiber and a non-aqueous medium dyeing method with cationic dyes. This method addresses the problems of difficult dyeing and limited color options associated with oxidized fibers. By blending acrylic chlorofiber with oxidized fibers, this invention ensures the flame-retardant properties of the needle-punched felt while allowing it to be dyed with cationic dyes in a non-aqueous medium. This solves the dyeing problem of oxidized fibers while being environmentally friendly and water-saving.

Description

Technical Field

[0001] This invention belongs to the field of dyeing technology, and specifically relates to an oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt and a non-aqueous dyeing method for cationic dyes. Background Technology

[0002] In recent years, the global market for safety and protective textiles has developed rapidly, with high-performance fibers and fabrics finding widespread application in various industries, especially in specialized sectors such as fire protection, welding, and petrochemicals. However, the high cost of high-performance fibers hinders their large-scale adoption. Oxidized fiber, a high-performance flame-retardant fiber, offers advantages such as long-lasting flame retardancy and affordability. It can be used in specialized industries like fire protection, police work, welding, and petrochemicals. This product utilizes a blend of oxidized fiber and acrylic fiber, employing a rational fiber ratio to leverage their respective properties, resulting in a high-performance, cost-effective safety protective needle-punched felt. Oxidized fiber is black and cannot be dyed, resulting in textiles with limited color variety and aesthetic appeal.

[0003] Oxidized fiber, also known as pre-oxidized fiber or pre-oxidized yarn, is an intermediate product in the carbon fiber manufacturing process. During pre-oxidation, cyclization, oxidation, and dehydrogenation reactions mainly occur. Through the pre-oxidation process, PAN macromolecules form heat-resistant ladder polymers with pyridine or naphthalene intercalated diazabenzene rings as the main components, making them non-melting and non-flammable during subsequent high-temperature carbonization, thus maintaining the fiber structure. Previously, the development of flame-retardant and heat-resistant textile materials relied on aramid and glass fibers, which had problems such as high cost and harm to human health. Oxidized fiber, as an intermediate product in the carbon fiber manufacturing process, possesses special heat-resistant and flame-retardant properties and is expected to be used to replace the aforementioned fiber fabrics.

[0004] Acrylonitrile fiber is a fiber polymerized from acrylonitrile monomers and vinyl compounds containing flame-retardant components, with the vinyl content ranging from 35% to 85%. Acrylonitrile fiber is not only high in strength and bright in color, with a wool-like feel, but also has high heat resistance due to the presence of chlorofiber, with a limiting oxygen index of 26% to 37%, and is also resistant to acids and chemicals.

[0005] Cationic dyes are commonly used textile dyes, also known as basic dyes or basal dyes, and are specifically designed for acrylonitrile fibers. Cationic dyes dissolve in water and then ionize, producing positively charged and colored ions. These ions can combine with the acidic groups of a third monomer in the needle-punched felt, thus coloring the fiber.

[0006] Oxidized fibers possess high flame retardancy (limiting oxygen index greater than 45%) and excellent thermal stability; they do not melt, soften, shrink, or drip during combustion, classifying them as non-flammable. They also offer good thermal insulation, resistance to acid and alkali corrosion, chemical environments, and radiation. However, due to defects such as low strength, low crimp, brittleness, and poor interfiber cohesion, oxidized fibers have poor spinnability, specifically manifested as difficulty in forming slivers, loose and low-strength yarns, and a high breakage rate during spinning. Currently, there are no non-aqueous dyeing methods for oxidized fiber / acrylic chlorofiber blended needle-punched felts, or even dyeing methods for oxidized fiber / acrylic chlorofiber needle-punched felts on the market. Summary of the Invention

[0007] The purpose of this invention is to provide a cationic dyeing method for flame-retardant needle-punched felt made of oxidized fiber / acrylic chlorofiber in a non-aqueous medium. This method addresses the problems of difficult dyeing of oxidized fiber and limited color options. This invention selects a blend of acrylonitrile and oxidized fiber, ensuring the flame-retardant properties of the needle-punched felt, and allows the needle-punched felt to be dyed with cationic dyes in a non-aqueous medium. This solves the dyeing problem of oxidized fiber while being environmentally friendly and water-saving.

[0008] The technical solution adopted by this invention to solve its technical problem is:

[0009] A cationic dyeing method for fire-resistant needle-punched felt made of oxidized fiber / acrylic chlorofiber using a non-aqueous medium includes the following steps:

[0010] S1. Needle punching of needle-punched felt; Needle-punched oxidized fiber / acrylic chlorofiber needle-punched felt contains the following raw materials by weight percentage: 30% to 50% oxidized fiber and 50% to 70% acrylic chlorofiber;

[0011] S2. Pre-treat the needled felt obtained from S1 in water at a temperature of 50-80℃, a bath ratio of 1:3-1:50, a time of 20-70 min, and a pH of 4-6, and then dry it.

[0012] S3. Prepare a non-aqueous medium using isoalkanes, surfactants, and co-surfactants; the mass ratio of surfactant, co-surfactant, and isoalkanes is 1:(1-5):(1-10);

[0013] S4. Add cationic dye to the non-aqueous medium prepared in S3, and then add pretreated needle-punched felt for dyeing.

[0014] S5. Take out the dyed needle-punched felt obtained in S4, rinse with cold water and soap to remove surface dye.

[0015] The cationic dye is a variety of conventional cationic dyes, such as cationic red X-GRL, cationic blue X-BL, or cationic golden yellow X-GI.

[0016] Currently, the most widely used carbon fiber is polyacrylonitrile (PAN)-based carbon fiber. Its preparation method involves copolymerizing acrylonitrile with certain monomers to obtain PAN. Then, using a spinning solution containing PAN, nascent PAN fibers are obtained through wet spinning, dry spinning, or dry-jet wet spinning. These fibers undergo post-treatment to obtain carbon fiber precursor fibers (also called carbon fiber filaments). These precursor fibers are then pre-oxidized at 200–400°C under an oxidizing atmosphere to obtain oxidized fibers (sometimes called oxidized fibers, flame-retardant fibers, flame-resistant fibers, or pre-oxidized fibers). Finally, the oxidized fibers are carbonized under high-temperature conditions (generally above 1000°C) and an inert atmosphere, such as at even higher temperatures (generally above 2500°C) under an inert atmosphere, to obtain graphitized carbon fibers. The oxidized fibers described in this invention are an intermediate product of this process.

[0017] This invention uses oxidized fiber and acrylonitrile chlorofiber to produce needle-punched felt, and then dyes the oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt with cationic dyes in a non-aqueous medium. While ensuring the flame retardancy of the oxidized fiber, this invention improves upon the problem of the limited color range of the oxidized fiber, and significantly reduces water consumption compared to traditional water bath dyeing. For the needle punching of the oxidized fiber / acrylic chlorofiber, the acrylonitrile chlorofiber can be blended using acrylonitrile chlorofiber dyed using the dyeing method of this invention. Alternatively, the oxidized fiber / acrylic chlorofiber needle-punched felt can be dyed using the dyeing method of this invention after needle punching.

[0018] In this invention, the purpose of S1 blending is to improve the color problem of oxidized fibers by using flame-retardant acrylonitrile. The purpose of S2 soaking the needle-punched felt is to achieve rapid dyeing with cationic dyes in subsequent steps. S3 prepares a non-aqueous medium, and S4 dyes the needle-punched felt using a non-aqueous medium. S5 soaping removes the floating dye from the surface of the dyed needle-punched felt.

[0019] Preferably, the isoalkanes are alkanes with 10-20 carbon atoms and no other special groups except for methyl and methylene groups; the surfactants and co-surfactants are nonionic / anionic / cationic surfactants and co-surfactants soluble in the isoalkanes.

[0020] As a preferred embodiment, the specific steps of S4 are as follows: cationic dye is added to the non-aqueous medium in S3, the amount of cationic dye is 0.2-5% (owf), and then the pretreated needle-punched felt in S2 is added, the liquor ratio is 1:10-1:50, the initial dyeing temperature is 60-80℃, the temperature is increased to 85-120℃ at 0.5-2℃ / min, the dyeing time is 15-60min; then the temperature is decreased to 60-80℃ at 0.5-2℃ / min.

[0021] Preferably, the amount of cations added to the non-aqueous medium in S4 is 1.5–2.5% (owf).

[0022] As a preferred option, the initial dyeing temperature for needle-punched felt dyeing in S4 is 70–75℃, and the liquor ratio is 1:15–1:25.

[0023] As a preferred option, after the needle-punched felt in S4 is dyed, the temperature of the needle-punched felt is increased to 105-115℃ at a rate of 1-1.5℃ / min, and the dyeing time is 20-30min.

[0024] As a preferred option, after staining the needle-punched felt in S4, the temperature is lowered to 65-70℃, and the cooling rate is 1-1.5℃ / min.

[0025] As a preferred embodiment, the soaping method described in S5 is as follows: first, take out the needle-punched felt and rinse it with cold water for 10 minutes, and then treat it with the prepared soaping solution for 10 minutes.

[0026] The soap washing solution is formulated with 2g / L anhydrous sodium carbonate, 2g / L soap flakes, and a bath ratio of 1:40. The soap is boiled in the soap washing solution at 95℃ for 10 minutes.

[0027] Preferably, the temperature of the needle-punched felt pretreatment in S2 is 50-60℃, the bath ratio is 8:1-10:1, the pretreatment time is 30-50 min, and the pH of the water in the pretreatment is 4-5.

[0028] Preferably, the isoalkane in the non-aqueous medium of S3 has 12 to 16 carbon atoms, the surfactant is TX-10 or MOA-3, and the co-surfactant is n-octanol or n-butanol.

[0029] Preferably, the mass ratio of the surfactant, co-surfactant, and isoparaffin in the non-aqueous medium configuration in S3 is 1:1.5:10.

[0030] As a preferred embodiment, the needle-punching steps for S1 and the needle-punched felt are as follows:

[0031] Blending box: Raw materials such as oxidized fiber and acrylonitrile fiber are put into the blending box for loosening and mixing, and then conveyed to the middle blending box for uniform fiber layer mixing by vibration.

[0032] Carding machine: It sorts the oxidized fibers and acrylonitrile fibers that have been processed in the cotton blending box into single fibers, then forms a thin layer of web fibers, and then gathers them into fiber strips and sends them to the web laying machine.

[0033] Web laying machine: Receives fiber strips from the carding machine, lays them into a web, and then sends the web to the needle punching machine;

[0034] Needle punching machine: This machine pre-reinforces the fiber web to form a greige fabric, then uses triangular or other shaped cross-sections with barbs on the edges to further reinforce the fiber web, repeating the piercing process repeatedly; the needle punching density is 500–1100 needles / cm². 2The acupuncture frequency is 500-1000 times / min, and the acupuncture depth is 4-15mm.

[0035] The blending ratio for needle-punched felt is any blending ratio that allows oxidized fibers and acrylonitrile fibers to be blended and formed.

[0036] The needle-punching method has little effect on the flame retardancy of the oxidized fiber. When blended with acrylonitrile, the dyeing method of this invention makes the oxidized fiber needle-punched felt no longer just black, and its properties are not changed after dyeing.

[0037] Preferably, the needle-punching density of the needle-punched oxidized fiber / acrylic chlorofiber needle-punched felt in S1 is 800-1000 needles / cm². 2 The acupuncture frequency is 700-800 times / min, and the acupuncture depth is 4-9mm.

[0038] An oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt obtained by the cationic dye non-aqueous medium dyeing method described in this invention.

[0039] This invention employs a blend of oxidized fiber and acrylic fiber using needle punching to improve the weaving and dyeing problems of oxidized fiber. Compared with existing technologies, the advantages of this invention are:

[0040] 1. In the prior art, oxidized fiber needle-punched felt products can only be black due to the limitations of dyeing technology. However, the dyeing method of the present invention enables the color dyeing of oxidized fiber needle-punched felt. Moreover, the dyeing method of the present invention has little impact on the flame retardancy of the product, so that it can not only be used in special places with high flame retardancy requirements, like oxidized fiber felt, but also in more civilian places.

[0041] 2. The oxidized fiber / acrylic chlorofiber needle-punched felt obtained by the present invention has better flame retardant properties than acrylic chlorofiber felt because it is made by blending oxidized fiber and acrylic chlorofiber through needle punching.

[0042] 3. Dyeing has virtually no impact on the original properties of oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt. The LOI value of the needle-punched felt after dyeing is 30-40.

[0043] 4. The main dyeing process of this invention is carried out in a non-aqueous medium, and water is only used in the pretreatment of needle-punched felt, which saves a lot of dyeing water compared with traditional water bath dyeing.

[0044] 5. The isoparaffins used in this invention are colorless and odorless, and are harmless to the human body and the environment. Attached Figure Description

[0045] Figure 1 These are samples (a) stained in Example 1 and samples (b) stained in Comparative Example 1. The staining temperatures differ from those in Example 1. The K / S values ​​(c) of the samples at the staining temperatures (90, 95, 100, 105, 110, 115, 120, 125℃) are also shown.

[0046] Figure 2 The samples are (a) after staining in Example 2 and (b) after staining in Comparative Example 2. The staining time is different from that in Example 2. The K / S values ​​of the samples (c) are at the staining times (5, 10, 15, 20, 25, 30, 35 min).

[0047] Figure 3 These are samples (a) stained in Example 3 and samples (b) stained in Comparative Example 3. The staining bath ratios are different from those in Example 3. The K / S values ​​of the samples (c) are shown when the staining bath ratios are (1:10, 1:20, 1:30, 1:40, 1:50).

[0048] Figure 4 The samples are (a) after staining in Example 4 and (b) after staining in Comparative Example 4. The amount of dye used in the staining in Example 4 is different. The K / S values ​​of the samples (c) are when the amount of dye used is (0.25%, 0.75%, 1.25%, 1.75%, 2.25%, 2.75%).

[0049] Figure 5 These are samples (a) stained in Example 5 and samples (b) stained in Comparative Example 5, which have different staining colors from those in Example 5.

[0050] Figure 6 These are samples (a) stained in Example 6 and samples (b) stained in Comparative Example 6, which use different staining media than those in Example 6.

[0051] Figure 7 This is the sample from Example 4(a) after being burned with a lighter for 10 seconds;

[0052] Figure 8 This is a process curve diagram of the conventional water bath dyeing method described in Comparative Example 6. Detailed Implementation

[0053] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0054] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0055] The present invention will now be further illustrated with specific examples. The following embodiments are only for explaining the present invention and do not constitute a limitation thereof. The test samples and test procedures used in the following embodiments include the following (if the specific experimental conditions are not specified in the embodiments, they are usually performed according to conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following embodiments can be obtained commercially unless otherwise specified).

[0056] The oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt produced by the process of this invention comprises, by weight percentage, the following raw materials: 30%–50% oxidized fiber and 50%–70% acrylonitrile chlorofiber. Within this range, its LOI value is 30–41.

[0057] Example: Preparation of needle-punched felt

[0058] The needle-punching steps for needle-punched felt are as follows:

[0059] Blending box: Raw materials such as oxidized fiber and acrylonitrile fiber are put into the blending box at a mass ratio of 1:1 for loosening and mixing, and then conveyed to the middle blending box for vibration to mix the fiber layer evenly.

[0060] Carding machine: It sorts the oxidized fibers and acrylonitrile fibers that have been processed in the cotton blending box into single fibers, then forms a thin layer of web fibers, and then gathers them into fiber strips and sends them to the web laying machine.

[0061] Web laying machine: Receives fiber strips from the carding machine, lays them into a web, and then sends the web to the needle punching machine;

[0062] Needle punching machine: This machine pre-reinforces the fiber web to form a greige fabric, then uses triangular or other shaped cross-sections with barbs on the edges to further reinforce the fiber web, repeating the piercing process repeatedly; the needle punching density is 500–1100 needles / cm². 2 The acupuncture frequency is 500-1000 times / min, and the acupuncture depth is 4-15mm.

[0063] In the following examples, the oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt used is 50 / 50 (i.e., the raw material is 50% oxidized fiber + 50% acrylic chlorofiber).

[0064] Example 1:

[0065] The needle-punching process of oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt and its non-aqueous dyeing with cationic dyes are described in the following steps:

[0066] (1) Pretreatment of needle-punched felt: Weigh 2g of needle-punched felt, soak it in water at 60℃ with a bath ratio of 1:8 and pH of 4, take it out after 40min and dry it for later use.

[0067] (2) Preparation in a non-aqueous medium: Isoalkanes, TX-10, and n-octanol were shaken thoroughly at a mass ratio of 1:1.5:10;

[0068] (3) Dyeing: Measure the non-aqueous medium, add the dye, shake thoroughly, and then place the pretreated needle-punched felt into the dye bath at a liquor ratio of 1:20. The initial dyeing temperature is 75℃, and the temperature is increased to 110℃ at a rate of 1℃ / min. The dyeing time is 30 min. Then the temperature is decreased to 65℃ at a rate of 1.5℃ / min.

[0069] (4) Soap washing: First, take out the needle-punched felt and rinse it with cold water for 10 minutes. Then, prepare a soap washing solution containing 2 g / L of anhydrous sodium carbonate, 2 g / L of soap flakes, and a bath ratio of 1:40. Soap the felt in the soap washing solution at 95℃ for 10 minutes. Finally, wash with water and dry to obtain dyed needle-punched felt.

[0070] The staining formula and conditions in the staining method are as follows:

[0071] Cationic dye (Cationic Red X-GRL): 2% (owf)

[0072] Needle-punched felt weight: 2g

[0073] Oxidized fiber / acrylic 50 / 50

[0074] Bath ratio: 1:20

[0075] The stained sample is red, see Figure 1 a.

[0076] Comparative Example 1: Staining temperature was reduced from 110℃ to 95℃

[0077] During dyeing, the dyeing temperature was increased from 1℃ / min after dyeing to 95℃. The other specific dyeing methods and process conditions were the same as in Example 1.

[0078] The stained sample is red, see Figure 1 b. By Figure 1 The results show that the staining depth of the sample in Example 1 is higher than that in Comparative Example 1, proving that the preferred staining temperature range can achieve better staining results. A staining temperature of 110℃ is the preferred option.

[0079] Under the same experimental conditions, staining experiments at multiple staining temperatures (90, 95, 100, 105, 110, 115, 120, 125℃) were conducted using the method described above, and the K / S values ​​of the samples were measured. The experimental results are shown in […]. Figure 1 c. The results showed that a staining temperature of 110℃ was the preferred option.

[0080] Example 2:

[0081] The needle-punching process of oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt and its non-aqueous dyeing with cationic dyes are described in the following steps:

[0082] (1) Pretreatment of needle-punched felt: Weigh 2g of needle-punched felt, soak it in water at 65℃ with a bath ratio of 1:9 and pH of 4.5, take it out after 40min, and dry it for later use.

[0083] (2) Preparation in a non-aqueous medium: Isoalkanes, TX-10, and n-octanol were shaken thoroughly at a mass ratio of 1:1.5:10;

[0084] (3) Dyeing: Measure the non-aqueous medium, add the dye, shake thoroughly, and then place the pretreated needle-punched felt into the dye bath at a liquor ratio of 1:20. The initial dyeing temperature is 70℃, and the temperature is increased to 110℃ at a rate of 1℃ / min. The dyeing time is 30min. Then the temperature is decreased to 65℃ at a rate of 1.5℃ / min.

[0085] (4) Soap washing: First, take out the needle-punched felt and rinse it with cold water for 10 minutes. Then, prepare a soap washing solution containing 2 g / L of anhydrous sodium carbonate, 2 g / L of soap flakes, and a bath ratio of 1:40. Soap the felt in the soap washing solution at 95℃ for 10 minutes. Finally, wash with water and dry to obtain dyed needle-punched felt.

[0086] The staining formula and conditions in the staining method are as follows:

[0087] Cationic dye (Cationic Blue X-BL): 2% (owf)

[0088] Needle-punched felt weight: 2g

[0089] Oxidized fiber / acrylic 50 / 50

[0090] Bath ratio: 1:20

[0091] The stained sample is blue, see Figure 2 a.

[0092] The staining time for Comparative Example 2 was reduced from 30 min to 15 min.

[0093] The dyeing time is 15 minutes, and the other specific dyeing methods and process conditions are the same as in Example 2.

[0094] The stained sample is blue, see Figure 2 b. By Figure 2 It can be seen that the staining depth of the sample in Example 2 is higher than that in Comparative Example 2, proving that a staining time of 30 minutes can achieve a better staining effect.

[0095] Under the same experimental conditions, staining experiments were conducted at multiple time points (5, 10, 15, 20, 25, 30, 35 min) using the method described above, and the K / S values ​​of the samples were measured. The experimental results are shown in […]. Figure 2 c. The results showed that a staining time of 30 minutes was the preferred option.

[0096] Example 3:

[0097] The needle-punching process of oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt and its non-aqueous dyeing with cationic dyes are described in the following steps:

[0098] (1) Pretreatment of needle-punched felt: Weigh 2g of needle-punched felt, soak it in water at 60℃ with a bath ratio of 1:8 and pH of 4.5, take it out after 40min, and dry it for later use.

[0099] (2) Preparation in a non-aqueous medium: Isoalkanes, TX-10, and n-octanol were shaken thoroughly at a mass ratio of 1:1.5:10;

[0100] (3) Dyeing: Measure the non-aqueous medium, add the dye, shake thoroughly, and then place the pretreated needle-punched felt into the dye bath at a liquor ratio of 1:20. The initial dyeing temperature is 75℃, and the temperature is increased to 110℃ at a rate of 1℃ / min. The dyeing time is 30min. Then the temperature is decreased to 70℃ at a rate of 1.5℃ / min.

[0101] (4) Soap washing: First, take out the needle-punched felt and rinse it with cold water for 10 minutes. Then, prepare a soap washing solution containing 2 g / L of anhydrous sodium carbonate, 2 g / L of soap flakes, and a bath ratio of 1:40. Soap the felt in the soap washing solution at 95℃ for 10 minutes. Finally, wash with water and dry to obtain dyed needle-punched felt.

[0102] The staining formula and conditions in the staining method are as follows:

[0103] Cationic dye (Cationic Golden Yellow X-GI): 2% (owf)

[0104] Needle-punched felt weight: 2g

[0105] Oxidized fiber / acrylic 50 / 50

[0106] Bath ratio: 1:20

[0107] The stained sample is golden yellow, see Figure 3 a.

[0108] The staining bath ratio for Comparative Example 3 was changed from 1:20 to 1:10.

[0109] The dyeing bath ratio was 1:10, and the remaining dyeing methods and process conditions were the same as in Example 3.

[0110] The stained sample is yellow, see Figure 3 b. By Figure 3It can be seen that the staining depth of the sample in Example 3 is higher than that in Comparative Example 3, proving that a staining bath ratio of 1:20 can achieve better staining effect, that is, a staining bath ratio of 1:20 is the preferred option.

[0111] Under the same experimental conditions, staining experiments with multiple liquor ratios (1:10, 1:20, 1:30, 1:40, 1:50) were tested using the method described above, and the K / S values ​​of the samples were measured. The experimental results are shown in […]. Figure 3 c. The results show that a staining bath ratio of 1:20 can achieve better staining results.

[0112] Example 4:

[0113] The needle-punching process of oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt and its non-aqueous dyeing with cationic dyes are described in the following steps:

[0114] (1) Pretreatment of needle-punched felt: Weigh 2g of needle-punched felt, soak it in water at 65℃ with a bath ratio of 1:9 and pH of 4.5, take it out after 30min, and dry it for later use.

[0115] (2) Preparation in a non-aqueous medium: Isoalkanes, TX-10, and n-octanol were shaken thoroughly at a mass ratio of 1:1.5:10;

[0116] (3) Dyeing: Measure the non-aqueous medium, add the dye, shake thoroughly, and then place the pretreated needle-punched felt into the dye bath at a liquor ratio of 1:20. The initial dyeing temperature is 75℃, and the temperature is increased to 95℃ at a rate of 1℃ / min. The dyeing time is 30 min. Then the temperature is decreased to 65℃ at a rate of 1.5℃ / min.

[0117] (4) Soap washing: First, take out the needle-punched felt and rinse it with cold water for 10 minutes. Then, prepare a soap washing solution containing 2 g / L of anhydrous sodium carbonate, 2 g / L of soap flakes, and a bath ratio of 1:10. Soap the felt in the soap washing solution at 95℃ for 10 minutes. Finally, wash with water and dry to obtain dyed needle-punched felt.

[0118] The staining formula and conditions in the staining method are as follows:

[0119] Cationic dye (Cationic Red X-GRL): 2% (owf)

[0120] Needle-punched felt weight: 2g

[0121] Oxidized fiber / acrylic 50 / 50

[0122] Bath ratio: 1:20

[0123] The stained sample is red, see Figure 4 a.

[0124] In Comparative Example 4, the dye dosage was reduced from 2% (owf) to 0.5% (owf).

[0125] The amount of dye used was 0.5% (owf), and the remaining dyeing methods and process conditions were the same as in Example 4.

[0126] The stained sample is red, see Figure 4 b. By Figure 4 It can be seen that the staining depth of the sample in Example 4 is higher than that in Comparative Example 4, proving that a dye dosage of 2% (owf) can achieve a better staining effect. Therefore, a dye dosage of 2% (owf) is the preferred option.

[0127] Under the same experimental conditions, dyeing experiments were conducted with multiple dye dosages (0.25%, 0.75%, 1.25%, 1.75%, 2.25%, 2.75%) using the method described above, and the K / S values ​​of the samples were measured. The experimental results are shown in [the table below]. Figure 4 c. Experiments have shown that the dyeing effect is optimal when the dye dosage is 2% (owf).

[0128] from Figure 1-4 As can be seen, under the same dyeing formula and pretreatment, the dyeing process of the present invention can achieve better dyeing rate and more uniform dyeing when dyeing oxidized fiber / acrylic chlorofiber.

[0129] Example 5:

[0130] The needle-punching process of oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt and its non-aqueous dyeing with cationic dyes are described in the following steps:

[0131] (1) Pretreatment of needle-punched felt: Weigh 2g of needle-punched felt, soak it in water at 65℃ with a bath ratio of 1:9 and pH of 4.5, take it out after 30min, and dry it for later use.

[0132] (2) Preparation in a non-aqueous medium: Isoalkanes, TX-10, and n-octanol were shaken thoroughly at a mass ratio of 1:1.5:10;

[0133] (3) Dyeing: Measure the non-aqueous medium, add the dye, shake thoroughly, and then place the pretreated needle-punched felt into the dye bath at a liquor ratio of 1:20. The initial dyeing temperature is 75℃, and the temperature is increased to 95℃ at a rate of 1℃ / min. The dyeing time is 30 min. Then the temperature is decreased to 65℃ at a rate of 1.5℃ / min.

[0134] (4) Soap washing: First, take out the needle-punched felt and rinse it with cold water for 10 minutes. Then, prepare a soap washing solution containing 2 g / L of anhydrous sodium carbonate, 2 g / L of soap flakes, and a bath ratio of 1:10. Soap the felt in the soap washing solution at 95℃ for 10 minutes. Finally, wash with water and dry to obtain dyed needle-punched felt.

[0135] The staining formula and conditions in the staining method are as follows:

[0136] Cationic dye (Cationic Red X-GRL): 2% (owf)

[0137] Needle-punched felt weight: 2g

[0138] Oxidized fiber / acrylic 50 / 50

[0139] Bath ratio: 1:20

[0140] The stained sample is red, see Figure 5 a.

[0141] Comparative Example 5: Cationic dyes of different colors

[0142] The dye used was cationic blue X-BL, and the other specific dyeing methods and process conditions were the same as in Example 5.

[0143] The stained sample is blue, see Figure 5 b.

[0144] Figure 5 It can be seen that the dyeing method of the present invention is applicable to cationic dyes of different colors. Figure 5 As can be seen, both Example 5 and Comparative Example 5 were able to complete the dyeing process, proving that the dyeing method of the present invention can be used to dye different colors of this type of cationic dye.

[0145] Example 6:

[0146] The needle-punching process of oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt and its non-aqueous dyeing with cationic dyes are described in the following steps:

[0147] (1) Pretreatment of needle-punched felt: Weigh 2g of needle-punched felt, soak it in water at 65℃ with a bath ratio of 1:9 and pH of 4.5, take it out after 30min, and dry it for later use.

[0148] (2) Preparation in a non-aqueous medium: Isoalkanes, TX-10, and n-octanol were shaken thoroughly at a mass ratio of 1:1.5:10;

[0149] (3) Dyeing: Measure the non-aqueous medium, add the dye, shake thoroughly, and then place the pretreated needle-punched felt into the dye bath at a liquor ratio of 1:20. The initial dyeing temperature is 75℃, and the temperature is increased to 95℃ at a rate of 1℃ / min. The dyeing time is 30 min. Then the temperature is decreased to 65℃ at a rate of 1.5℃ / min.

[0150] (4) Soap washing: First, take out the needle-punched felt and rinse it with cold water for 10 minutes. Then, prepare a soap washing solution containing 2 g / L of anhydrous sodium carbonate, 2 g / L of soap flakes, and a bath ratio of 1:10. Soap the felt in the soap washing solution at 95℃ for 10 minutes. Finally, wash with water and dry to obtain dyed needle-punched felt.

[0151] The staining formula and conditions in the staining method are as follows:

[0152] Cationic dye (Cationic Red X-GRL): 2% (owf)

[0153] Needle-punched felt weight: 2g

[0154] Oxidized fiber / acrylic 50 / 50

[0155] Bath ratio: 1:20

[0156] The stained sample is red, see Figure 6 a.

[0157] Comparative Example 6

[0158] The dyeing method used is the conventional water bath method. The dyeing formula is shown in Table 1, and the process curve is as follows: Figure 8 As shown, the remaining identical parts, such as needle-punched felt and pretreatment, dyes and dosages, are the same as in Example 6.

[0159] The stained sample is red, see Figure 6 b. By Figure 6 It can be seen that both Example 6 and Comparative Example 6 can complete the dyeing with cationic dyes. However, Example 6 only requires heating from 75°C to 95°C and then holding at that temperature for 30 minutes to complete the dyeing. Traditional water baths use a stepwise method to control the temperature rise in order to ensure uniform dyeing, and the dyeing time is 100-120 minutes, which is twice or more than the time required by this invention. Furthermore, it requires the addition of acids and salts for dyeing promotion, which is not conducive to environmental protection.

[0160] Figure 6 It can be seen that the dyeing method of the present invention is more suitable for dyeing oxidized fiber / acrylic chlorofiber needle-punched felt because the dyeing time is shorter than that of the traditional water bath. Therefore, this method can be used for dyeing oxidized fiber / acrylic chlorofiber needle-punched felt.

[0161] Table 1. Formulations for water-dyeing acrylic and chlorofibers with cationic dyes

[0162] Acrylic chlorofiber 1g cationic dyes 2% (owf) 0.02g HAc 2％～3％ 0.02g <![CDATA[Na2CO3]]> 1％ 0.01g <![CDATA[Na2SO4]]> 0～10％ 0.05g Bath ratio 1:20 20ml

[0163] As shown in Table 1, when cationic dyes are used to dye acrylonitrile fibers, the addition of salts can increase the affinity between the dye and the acrylonitrile fibers, thus improving the dye's adsorption and fixation properties. The addition of acids can promote the reaction between the dye and fiber groups, enhancing the dye's fixation and durability. However, the addition of both acids and salts during and after dyeing can cause environmental pollution, which is detrimental to environmental protection.

[0164] As a high-performance functional nonwoven fabric, the flame retardancy of oxidized fiber / acrylic chlorofiber felt takes precedence over its appearance. Therefore, its flame retardancy cannot be significantly reduced by dyeing. Thus, the LOI (limiting oxygen index) of oxidized fiber felt, oxidized fiber / acrylic chlorofiber felt, and dyed oxidized fiber / acrylic chlorofiber felt (50 / 50) were compared, and the data are shown in Table 2.

[0165] Table 2

[0166]

[0167] The limiting oxygen index (LOI) is the volume fraction of oxygen required for a polymer to sustain combustion in an oxygen-nitrogen mixture. It is an index characterizing the combustion behavior of a material. The LIO is determined using a candle test, where a polymer rod is burned downwards under specific conditions. Generally, an LIO of 22 is considered sufficient for the substance to burn in air. The LIO is the minimum oxygen concentration required for a material to undergo flaming combustion in an oxygen-nitrogen mixture under specified conditions. It is expressed as a volume percentage of oxygen.

[0168] As shown in Table 2, the LOI value of the dyed oxidized fiber / acrylic chlorofiber needle-punched felt of this invention is lower than that of the oxidized fiber needle-punched felt because the flame retardant properties of acrylic chlorofiber are lower than those of oxidized fiber. However, since both oxidized fiber and acrylic chlorofiber are flame-retardant fibers, the oxidized fiber / acrylic chlorofiber needle-punched felt can still be used in special industries such as fire fighting, police work, welding, and petrochemicals. The LOI value of the dyed oxidized fiber / acrylic chlorofiber needle-punched felt is not significantly different from that of the untreated oxidized fiber / acrylic chlorofiber needle-punched felt, and it still retains the properties of being non-combustible and non-dripping. Figure 7 As shown. The dyeing method of the present invention has little impact on the flame retardancy of the product, making it more widely applicable than oxidized fiber felt.

[0169] To demonstrate that the optimal dyeing temperature is 105–115°C, experiments were conducted in Example 1 and Comparative Example 1.

[0170] To demonstrate that the optimal staining time is 20–30 min, experiments were conducted in Example 2 and Comparative Example 2.

[0171] To demonstrate that the preferred dyeing bath ratio is 1:15 to 1:25, experiments were conducted in Example 3 and Comparative Example 3.

[0172] To demonstrate that the preferred amount of dye used is 1.5–2.5% (owf), experiments were conducted in Example 4 and Comparative Example 4.

[0173] To demonstrate that the dyeing method can be used with cationic dyes of different colors, experiments were conducted in Example 5 and Comparative Example 5.

[0174] To demonstrate that this staining method is superior to the traditional water bath staining method in terms of time and environmental friendliness, experiments were conducted in Example 6 and Comparative Example 6.

[0175] from Figure 1-4 As can be seen, under the same dyeing formula and pretreatment, the preferred dyeing process of the present invention can achieve a deeper dyeing effect and better leveling properties when dyeing oxidized fibers / acrylic chlorofibers. Figure 5It can be seen that the dyeing method of the present invention is applicable to cationic dyes of different colors. Figure 6 It can be seen that the dyeing method of the present invention has a shorter dyeing time than the traditional water bath (50 minutes for Example 6 and 100 minutes for Comparative Example 6), and the water bath, due to its longer dyeing time, may cause a certain degree of softening in the oxidized fiber / acrylic chlorofiber needle-punched felt. Table 2 shows that the production and dyeing of the oxidized fiber / acrylic chlorofiber needle-punched felt in this invention results in flame retardant properties lower than those of oxidized fiber felt, but it still possesses non-flammable and non-dripping properties, and can produce various colors, thus having a wider range of applications than oxidized fiber felt. From... Figure 7 As can be seen, the oxidized fiber / acrylic chlorofiber needle-punched felt manufactured by this invention still has flame-retardant effect after being dyed by the dyeing method of this invention, and does not burn or drip.

[0176] In summary, the method of the present invention can be used for the production and dyeing of oxidized fiber / acrylic chlorofiber needle-punched felt.

[0177] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0178] The foregoing has provided a detailed description of the needle punching process and the non-aqueous dyeing of the oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A cationic dyeing method for fire-retardant needle-punched felt made of oxidized fiber / acrylic chlorofiber using a non-aqueous medium, characterized in that... The method includes the following steps: S1. Needle punching of needle-punched felt; Needle-punched oxidized fiber / acrylic chlorofiber needle-punched felt contains the following raw materials by weight percentage: oxidized fiber 30%–50%, acrylic chlorofiber 50%–70%; S2. Pre-treat the needled felt obtained from S1 in water at a temperature of 50–80 ℃, a bath ratio of 1:3–1:50, a time of 20–70 min, and a pH of 4–6, and then dry it. S3. Prepare a non-aqueous medium using isoalkanes, surfactants, and co-surfactants; the mass ratio of surfactants, co-surfactants, and isoalkanes is 1:(1-5):(1-10). The isoalkanes prepared in non-aqueous media have 12 to 16 carbon atoms, the surfactant is TX-10 or MOA-3, and the co-surfactant is n-octanol or n-butanol; S4. Add cationic dye to the non-aqueous medium prepared in S3, and then add pretreated needle-punched felt for dyeing. The specific steps are as follows: add cationic dye to the non-aqueous medium in S3, the amount of cationic dye is 0.2-5% (owf), then add the pretreated needle-punched felt in S2, the liquor ratio is 1:10-1:50, the initial dyeing temperature is 60-80 ℃, the temperature is increased to 85-120 ℃ at 0.5-2 ℃ / min, the dyeing time is 15-60 min; then the temperature is decreased to 60-80 ℃ at 0.5-2 ℃ / min. S5. Take out the dyed needle-punched felt obtained in S4, rinse with cold water and soap to remove surface dye.

2. The cationic dye non-aqueous medium dyeing method according to claim 1, characterized in that: The soaping method described in S5 is as follows: first, take out the needle-punched felt and rinse it with cold water for 10 minutes, and then treat it with the prepared soaping solution for 10 minutes. The soaping solution is formulated with 2 g / L anhydrous sodium carbonate, 2 g / L soap flakes, and a bath ratio of 1:

40. The soap is boiled in the soaping solution at 95 ℃ for 10 minutes.

3. The cationic dye non-aqueous medium dyeing method according to claim 1, characterized in that: The temperature for pretreatment of needle-punched felt in S2 is 50–60 °C, the bath ratio is 1:8–1:10, the pretreatment time is 30–50 min, and the pH of the water in the pretreatment is 4–5.

4. The cationic dye non-aqueous medium dyeing method according to claim 1, characterized in that: In S3, the mass ratio of surfactant, co-surfactant, and isoparaffin in the non-aqueous medium configuration is 1:1.5:

10.

5. The cationic dye non-aqueous medium dyeing method according to claim 1, characterized in that... S1. The needle-punching steps for needle-punched felt are as follows: Blending box: Raw materials such as oxidized fiber and acrylonitrile fiber are put into the blending box for loosening and mixing, and then conveyed to the middle blending box for uniform fiber layer mixing by vibration. Carding machine: It sorts the oxidized fibers and acrylonitrile fibers that have been processed in the cotton blending box into single fibers, then forms a thin layer of web fibers, and then gathers them into fiber strips and sends them to the web laying machine. Web laying machine: Receives fiber strips from the carding machine, lays them into a web, and then sends the web to the needle punching machine; Needle punching machine: This machine pre-reinforces the fiber web to form a grey fabric, then uses triangular or other shaped cross-sections with barbs on the edges to further reinforce the fiber web, repeating the piercing process repeatedly; the needle punching density is 500–1100 needles / cm². 2 The acupuncture frequency is 500-1000 times / min, and the acupuncture depth is 4-15 mm.

6. The cationic dye non-aqueous medium dyeing method according to claim 1, characterized in that: The needle-punching density of S1 needle-punched oxidized fiber / acrylic chlorofiber needle-punched felt is 800-1000 needles / cm². 2 The acupuncture frequency is 700-800 times / min, and the acupuncture depth is 4-9 mm.

7. An oxidized fiber / acrylic chlorofiber flame-retardant needle-punched felt obtained by the cationic dye non-aqueous medium dyeing method according to claim 1.

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