High color fastness nylon-polyamide knitted fabric dip dyeing process

Abstract

The application belongs to the technical field of cloth dyeing and specifically relates to a high-color-fastness black brocade knitwear fabric dip dyeing process; by adding special dyeing solution and dyeing additive, i.e., calcium chloride, into the brocade knitwear fabric, the dyeing brocade knitwear fabric is produced through two-stage temperature dyeing and fixing, the dyeing process of the application reduces the COD generated in the raw materials and subsequent treatment, improves the dye exhaustion rate so as to reduce the water consumption in the subsequent treatment, saves energy and reduces emissions, and improves the color fastness and dyeing depth of the product.

Description

Technical Field

[0001] This invention belongs to the field of fabric dyeing technology, specifically relating to a dyeing process for high color fastness black nylon-spandex knitted fabric. Background Technology

[0002] In today's trend of sportswear becoming more fashionable and fashion becoming more athletic, nylon-spandex knitted fabrics have become a leader in high-end sportswear fabrics, with demand steadily increasing. Versatile black is the dominant color in sportswear fabrics, accounting for up to 50% of all fabrics. In the past three years, black accounted for 49.83% of all sportswear fabrics. As high-end sportswear fabrics, black must possess excellent colorfastness, such as resistance to washing, water stains, sweat stains, and light. Furthermore, it must meet customer requirements to prevent color fading after soaking in hot water (>50℃) with commercially available laundry detergent.

[0003] 1:2 type metal complex acid dyes, known as neutral dyes, are the preferred dye type for black nylon-spandex fabrics. Their dyeing depth and economy are irreplaceable. Traditional dyeing processes usually add 0.8g / L to 1.0g / L glacial acetic acid to the dye bath to improve the dyeing depth of black. However, since normal polyamide fibers contain only one amino group with a content of 25 to 50 mmol / kg, which is 2% to 6% of wool containing 850 mmol / kg of multiple amino groups, acidic conditions cannot achieve exhaustion dyeing.

[0004] CN 110761089A discloses a one-bath dyeing and fixing method for nylon fabrics. The method involves adding acidic dyes and auxiliaries to the nylon fabric to be dyed, followed by dyeing and fixing steps to obtain the nylon fabric. In order to improve the dyeing depth of the fabric, the added auxiliaries include 0.4-0.6 g / L of organic acid-releasing agent. However, 5%-12% of unabsorbed dye remains in the final black dyeing residue. This remaining dye combines with the fixing agent to produce suspended matter that is difficult to wash out, and causes a large amount of COD emissions, resulting in environmental pollution.

[0005] In recent years, apparel customers have added a new testing requirement: that commercially available laundry detergents (such as Tide) should not fade after being soaked in hot water above 50°C (referred to as water fastness). Black nylon-spandex knitted fabrics dyed using the above-mentioned traditional acid dyeing process cannot meet this requirement.

[0006] In summary, existing nylon fabric dyeing processes generate large amounts of COD, causing serious pollution; they cannot completely immerse the fabric, resulting in residual dye in the dyeing residue combining with the fixing agent to produce suspended matter that is difficult to wash off; and the color fastness is insufficient, failing to meet the test requirement of not fading after soaking in hot water above 50°C with commercially available laundry detergents (Tide / Diaopai) (referred to as water fastness). Summary of the Invention

[0007] To address the problems in the prior art regarding the high COD emissions and severe pollution during the production of nylon-spandex fabrics; incomplete dyeing leading to residual dye and fixing agent combining in the dyeing residue to produce difficult-to-wash suspended matter; and insufficient color fastness, failing to meet the testing requirements for colorfastness after soaking in hot water above 50°C with commercially available laundry detergents (Tide / Diaopai) (referred to as water fastness), this invention proposes a high color fastness black nylon-spandex knitted fabric immersion dyeing process.

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

[0009] A low-carbon dyeing process for high colorfastness nylon-spandex knitted fabrics, comprising the following steps:

[0010] 1) Add dye liquor and dyeing auxiliary agent to the nylon-spandex knitted fabric to be dyed, first heat to 40-60℃ and keep warm for 10-30 minutes, then heat to 80-100℃ and dye for 30-50 minutes. The dyeing auxiliary agent is calcium chloride.

[0011] 2) After dyeing in step 1), the fabric is cooled to 60-80℃ for color fixing, and a color fixing agent is added during the color fixing process;

[0012] 3) After the color fixation is completed in step 2), the fabric is cooled to 40-50℃, drained, washed, and removed from the vat to obtain the dyed nylon-spandex knitted fabric.

[0013] The dyeing solution is prepared with acidic dyes, including one or more of CI Acid Yellow 220, CI Acid Violet 90, CI Acid Blue 193 and CI Acid Black 172, and the amount of acidic dye used is 2.0-8.0 (%) owf.

[0014] The ratio of the dyeing auxiliary agent to the dyeing solution is 0.2-2 g / L.

[0015] In step 1 above, since the glass transition temperature of nylon 6 is 45-60℃, the temperature needs to be raised slowly to ensure uniform dyeing. Preferably, the temperature is first raised to 55℃ and held for 20 minutes, and then raised to 98-100℃ for dyeing. In step 2, preferably, the fabric obtained after dyeing is cooled to 80℃. The fixing agent is acidic fixing agent DF-2539 from Guangdong Demei Fine Chemical Co., Ltd.

[0016] In this invention, dye liquor and dyeing auxiliaries are added to the nylon-spandex knitted fabric to be dyed. Based on the glass transition temperature of nylon 6, the dyeing rate is made uniform by two stages of heating and staged heat preservation, with two different heating rates. After dyeing, the temperature is lowered to fix the color. The fixing agent is an environmentally friendly aromatic sulfonic acid condensate, which is anionic like the dye. After forming a film with the dyed fabric, it improves the color fastness and saves washing water.

[0017] The dyeing auxiliary agent of this invention is calcium chloride, which has extremely high solubility in water and slight acidity. The complete ionization of calcium chloride promotes dyeing, and the slight acidity is conducive to the protonation of trace amino groups in nylon fibers, also showing a strong dyeing effect, so that the dye is almost completely absorbed, strengthening the bonds of various ions, molecules and hydrogen bonds between the dye and the fiber, and forming a chromite (chromite) that is difficult to dissolve in water. Its micro particles interlock with the fiber. Through the above improvements, this invention ensures the color depth and color fastness of the fabric after dyeing, making the color stable, while reducing COD emissions, saving energy and reducing emissions.

[0018] Compared to the widely used acid dyes NHF-S tri-color dyes from DyStar, the dyes selected in this invention have a greater advantage in color depth at the same dyeing depth and exhibit carbon reduction at the same depth.

[0019] Preferably, the amount of acid dye used includes:

[0020] CI Acid Yellow 220 0-3.0% (owf)

[0021] CI Acid Violet 90 0-4.0% (owf)

[0022] CI Acid Blue 193 0-5.0% (owf)

[0023] CI Acid Black 172 0-8.0% (owf).

[0024] This invention selects dark neutral dyes—the three primary colors of acid yellow and black—that have a high affinity for nylon fibers, disulfonic acid groups, and a symmetrical molecular structure. Compared to the widely used acid dyes NHF-S from DyStar, this invention offers a greater color depth at the same dyeing depth. The CI Acid Yellow 220, CI Acid Violet 90, CI Acid Blue 193, and CI Acid Black 172 correspond to the trade names of Hangzhou Xiasha Hengsheng Chemical Co., Ltd., namely Acid Yellow S-2G, Acid Violet MB, Acid Navy Blue R, and Acid Black MR, respectively. The dye ratio can be adjusted according to the product color requirements.

[0025] Preferably, the weight ratio of the nylon-spandex knitted fabric to be dyed to the dye liquor in step 1) is 1:6-20.

[0026] Preferably, the weight ratio of the nylon-spandex knitted fabric to be dyed in step 1) to the dye liquor is 1:20.

[0027] In this invention, the liquor ratio, or mass ratio, has a significant impact on the color difference of the dyed fabric. With the same amount of dye, the larger the amount of dye liquor, the lower its concentration, and the less dye can be applied to the fabric under the same conditions, resulting in a greater color difference. Dyeing auxiliaries can promote the dye to be applied to the fabric. The amount of dyeing auxiliaries can be changed according to the color requirements of the fabric. As the color increases from dark to medium, the amount of dyeing auxiliaries gradually decreases. However, excessive dyeing auxiliaries will no longer have a significant dyeing-promoting effect, as there is a certain threshold.

[0028] Preferably, in step 1), the dye solution is added at a constant rate for 15-20 minutes. After the dye solution is added for 5 minutes, the dyeing auxiliary agent is added at a constant rate for 15 minutes. After the dyeing auxiliary agent is added, the process is run for 5 minutes.

[0029] Preferably, a wetting treatment is required before adding the dye solution.

[0030] The humidification temperature is 20-40℃.

[0031] The wetting time is 10-20 minutes.

[0032] As a preferred technical solution, the wetting temperature is 30°C and the wetting time is 10 minutes.

[0033] Preferably, the nylon-spandex knitted fabric to be dyed needs to undergo continuous water washing to remove oil stains and impurities from the fabric before wetting treatment.

[0034] Preferably, in step 1), the temperature is first increased to 50℃±1 at 1.0℃ / min and held for 10min, and then increased to 98℃ at 1.5℃ / min. In step 2), the temperature is decreased to 80℃ at 1℃ / min.

[0035] Preferably, the staining time in step 1) is 30-45 min.

[0036] Preferably, the staining time in step 1) is 45 min.

[0037] Preferably, the amount of color-fixing agent added in step 2) accounts for 2-3% of the mass of the nylon-spandex knitted fabric to be dyed.

[0038] The fixing agent is added at a constant rate 20 minutes after the start of the fixing process.

[0039] The color-fixing time is 50 minutes.

[0040] In this invention, the addition of a color-fixing agent can improve the color fastness of the fabric, but excessive use will cause glue stains on the fabric, thereby reducing product quality. Therefore, it is necessary to select an appropriate amount of color-fixing agent. Generally speaking, the longer the color-fixing time, the higher the color depth of the fabric. The appropriate color-fixing time can be selected according to the required color depth of the product.

[0041] The beneficial effects of this invention are:

[0042] 1. With the aid of calcium chloride, the dyeing rate of this invention increases by 8-10%. Based on an 80% emission reduction, the dyeing and fixing stages can reduce carbon dioxide emissions by 32 tons per year for a production of 1,000 tons of black nylon-spandex fabric.

[0043] 2. With the promotion of calcium chloride, the dye is almost completely absorbed, the dyeing depth is improved, and the dyeing depth can be increased by up to 4.137%. The full utilization of dye avoids the combination of residual dye and fixing agent to produce suspended matter that is difficult to wash out, thereby effectively reducing the water consumption of subsequent washing treatment and saving water resources.

[0044] 3. Improved dyeing depth and color fastness meet market demands. Products manufactured using this invention will not fade after soaking in hot water above 50°C with commercially available laundry detergent (Tide).

[0045] 4. Due to the addition of calcium chloride, the addition of glacial acetic acid or organic acid-releasing agents, leveling agents and softeners in the traditional process is eliminated, saving costs and reducing the introduction of corresponding COD, thus reducing pollution.

[0046] 5. Compared to the traditional process that uses glacial acetic acid as one of the dyeing auxiliaries, which is not sensitive to the purple component and causes purple residue, the present invention solves this problem by using calcium chloride as a dyeing auxiliary. Attached Figure Description

[0047] Figure 1 This is a process flow diagram of the high color fastness black nylon-spandex knitted fabric immersion dyeing process of the present invention.

[0048] Figure 2 A comparison diagram of staining residues of glacial acetic acid and calcium chloride used as staining auxiliaries is shown. In the diagram, 1 represents glacial acetic acid and 2 represents calcium chloride.

[0049] Figure 3 A color comparison of fabrics dyed further using residual dyeing solutions of glacial acetic acid and calcium chloride as dyeing auxiliaries. The left side shows glacial acetic acid, and the right side shows calcium chloride.

[0050] Figure 4 Comparison of color measurement results for black nylon-spandex fabric treated with glacial acetic acid / calcium chloride.

[0051] Figure 5This is a Munsell color coordinate system diagram. The origin of the coordinate system is HAC black. The dark red dot on the plane coordinate represents the hue of calcium chloride black. The red dot in the middle of the vertical coordinate on the right is HAC black, and the dark red spot represents the depth of calcium chloride black.

[0052] Figure 6 This is a dyeing diagram of black nylon feather yarn using calcium chloride instead of glacial acetic acid.

[0053] Figure 7 A comparison image showing the effects of soaking 5g of untreated black feather yarn prepared with calcium chloride / glacial acetic acid as dyeing auxiliaries in water at 95℃ and in hot water with soap.

[0054] Figure 8 The image shows the result of soaking 5g of black nylon-spandex fabric in 200ml of 50℃ hot water with 2g / L of Diaopai laundry detergent.

[0055] Figure 9 The images show a comparison between fabrics dyed with residual dye solution and raw fabric in Examples 1, 2, 3, and 4, and fabrics dyed directly. The fabric on the left is the fabric dyed directly. Detailed Implementation

[0056] 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.

[0057] The raw materials used in the embodiments and comparative examples of this invention are nylon-spandex double-sided matte fabrics made on a 40-needle circular knitting machine, with yarn count specifications of 75% 40D nylon + 25% 40D spandex; the selected dyeing machine is an overflow dyeing machine from Taiwan, China; the dyeing operation liquor ratio is set to 1:10 between the nylon-spandex knitted fabric to be dyed and the dye liquor.

[0058] The process flow diagram of the high color fastness black nylon-spandex knitted fabric impregnation dyeing process of the present invention is as follows: Figure 1 As shown.

[0059] The dyes selected in this invention are Acid Yellow S-2G, Acid Violet MB, Acid Navy Blue R, and Acid Black MR from Hangzhou Xiasha Hengsheng Chemical Co., Ltd.

[0060] Acidic leveling agent was purchased from Zhejiang Tongxiang Chemical Light Industry Co., Ltd.; color fixing agent was purchased from Guangdong Demei Fine Chemical Group Co., Ltd.; bath softener was purchased from [unspecified source]; organic acid-releasing agent was purchased from Hangzhou Kenwei Chemical Co., Ltd.; organic acid-releasing agent was purchased from Hangzhou Puston Chemical Co., Ltd.

[0061] Example 1:

[0062] A high colorfastness nylon-spandex knitted fabric immersion dyeing process, the process steps are as follows:

[0063] 1) The nylon-spandex knitted fabric to be dyed is continuously washed to remove oil stains and impurities from the greige fabric, then fed into the dyeing machine. It is moistened at 30°C for 5 minutes, and the dye liquor is slowly and evenly added for 15 minutes. After running for 5 minutes, calcium chloride is slowly and evenly added for 15 minutes. After running for 5 minutes, the temperature is raised to 55°C at a rate of 1°C / min and held for 10 minutes. Then the temperature is raised to 98°C at a rate of 1.5°C / min and dyed for 45 minutes. The ratio of calcium chloride to dye liquor is 1 g / L.

[0064] The ratio of the dye solution is:

[0065]

[0066]

[0067] 2) After dyeing, reduce the temperature to 80℃ at a rate of 1℃ / min and run for 20 minutes. Add 2% of the weight of the nylon-spandex knitted fabric to be dyed as a color-fixing agent and run for 30 minutes to finish color fixing.

[0068] 3) After the color fixation is completed, the temperature is lowered to 50℃, the liquid is drained, washed, and removed from the vat to obtain the dyed nylon-ammonia knitted fabric.

[0069] Example 2:

[0070] A high colorfastness nylon-spandex knitted fabric immersion dyeing process, the process steps are as follows:

[0071] 1) The nylon-spandex knitted fabric to be dyed is continuously washed to remove oil stains and impurities from the greige fabric, then fed into the dyeing machine. It is moistened at 30°C for 5 minutes, and the dye liquor is slowly and evenly added for 15 minutes. After running for 5 minutes, calcium chloride is slowly and evenly added for 15 minutes. After running for 5 minutes, the temperature is raised to 55°C at a rate of 1°C / min and held for 10 minutes. Then the temperature is raised to 98°C at a rate of 1.5°C / min and dyed for 45 minutes. The ratio of calcium chloride to dye liquor is 1 g / L.

[0072] The ratio of the dye solution is:

[0073] Acid Yellow S-2G 1.5% (owf)

[0074] Acid Violet MB 1.2% (owf)

[0075] Acidic dark blue R 0.5% (owf);

[0076] 2) After dyeing, reduce the temperature to 80℃ at a rate of 1℃ / min and run for 20 minutes. Add 2% of the weight of the nylon-spandex knitted fabric to be dyed as a color-fixing agent and run for 30 minutes to finish color fixing.

[0077] 3) After the color fixation is completed, the temperature is lowered to 50℃, the liquid is drained, washed, and removed from the vat to obtain the dyed nylon-ammonia knitted fabric.

[0078] Example 3:

[0079] A high colorfastness nylon-spandex knitted fabric immersion dyeing process, the process steps are as follows:

[0080] 1) The nylon-spandex knitted fabric to be dyed is continuously washed to remove oil stains and impurities from the fabric, then fed into the dyeing machine. It is moistened at 30°C for 5 minutes, and the dye liquor is slowly and evenly added for 20 minutes. After running for 5 minutes, calcium chloride is slowly and evenly added for 15 minutes. After running for 5 minutes, the temperature is raised to 55°C at a rate of 1°C / min and held for 10 minutes. Then the temperature is raised to 98°C at a rate of 1.5°C / min and dyed for 45 minutes. The ratio of calcium chloride to dye liquor is 1 g / L.

[0081] The ratio of the dye solution is:

[0082] Acid Yellow S-2G 1.0% (owf)

[0083] Acid Purple MB 2.6% (owf)

[0084] Acidic dark blue R 0.5% (owf);

[0085] 2) After dyeing, reduce the temperature to 80℃ at a rate of 1℃ / min and run for 20 minutes. Add 3% of the weight of the nylon-spandex knitted fabric to be dyed as a color-fixing agent and run for 30 minutes to finish color fixing.

[0086] 3) After the color fixation is completed, the temperature is lowered to 50℃, the liquid is drained, washed, and removed from the vat to obtain the dyed nylon-ammonia knitted fabric.

[0087] Example 4:

[0088] A high color fastness black nylon-spandex knitted fabric impregnation dyeing process, the process steps are as follows:

[0089] 1) The nylon-spandex knitted fabric to be dyed is continuously washed to remove oil stains and impurities from the fabric, then fed into the dyeing machine. It is moistened at 30°C for 5 minutes, and the dye liquor is slowly and evenly added for 20 minutes. After running for 5 minutes, calcium chloride is slowly and evenly added for 15 minutes. After running for 5 minutes, the temperature is raised to 55°C at a rate of 1°C / min and held for 10 minutes. Then the temperature is raised to 98°C at a rate of 1.5°C / min and dyed for 45 minutes. The ratio of calcium chloride to dye liquor is 1 g / L.

[0090] The ratio of the dye solution is:

[0091]

[0092] 2) After dyeing, reduce the temperature to 80℃ at a rate of 1℃ / min and run for 20 minutes. Add 3% of the weight of the nylon-spandex knitted fabric to be dyed as a color-fixing agent and run for 30 minutes to finish color fixing.

[0093] 3) After the color fixation is completed, the temperature is lowered to 50℃, the liquid is drained, washed, and removed from the vat to obtain the dyed nylon-ammonia knitted fabric.

[0094] The exhaustion rate, total color difference, and total depth of Examples 1-4 were tested. The exhaustion rate was measured by using a Datacolor colorimeter to measure the color of two fabrics after further dyeing with residual liquid and white pre-dyed fabric, and comparing their integ values ​​(color depth values). In Example 4, one-third of the fabric was extra-deep black, and the black dyeing depth was generally 5-6. Table 1 uses extra-deep black as an example.

[0095] The absorption rate, total color difference, and total depth test results of Examples 1-4 are shown in Table 1. The corresponding hue of Example 1 is dark gray, the corresponding hue of Example 2 is coffee, the corresponding color of Example 3 is navy blue, and the corresponding color of Example 4 is extra deep black.

[0096] Table 1. Test results for exhaustion rate, total color difference, and total depth in Examples 1-4.

[0097]

[0098]

[0099] Combination Figure 9 It is evident that the fabric of this invention fully absorbs dye during the production process, with an absorption rate of up to 99.7%, almost completely absorbing the dye. This greatly reduces carbon dioxide emissions, reduces the combination of dye and fixing agent, and reduces water consumption in subsequent processing, thus saving energy and reducing emissions.

[0100] The color fastness test results for Examples 1-4 are shown in Table 2. Among them, resistance to soap washing, acid perspiration, alkaline perspiration, water stains, and rubbing were tested. The test standards were in accordance with the corresponding national standards, namely ISO 105C06 A2S, ISO 105E04, ISO 105E04, ISO 105E01, ISO 105E01, and ISO 105X12. The method for testing the colorfastness after soaking in water was as follows: 5g of fabric was added to 200ml of 50℃ water, 2g of Tide or Diaopai laundry detergent was added, and the fabric was soaked for 15 minutes before observing whether the color faded.

[0101] Table 2 Colorfastness Test Table for Examples 1-4

[0102]

[0103] It is evident that the fabric produced by this invention achieves a level of 4-5 in tests of soap washing resistance, acid sweat resistance, alkali sweat resistance, water resistance, and abrasion resistance, exhibiting good color fastness. Furthermore, the fabric tested to be colorfast when soaked in water has passed all tests, thus meeting current market demands.

[0104] Comparative Example 1:

[0105] A method for one-bath dyeing and fixing of nylon fabrics (this method is Example 1 of invention patent CN110761089), the steps of which are as follows:

[0106] 1) After wetting the nylon fabric to be dyed at 40°C, add dyeing solution to it. The dyeing solution consists of acid dye and auxiliaries. The acid dye is added to the nylon fabric to be dyed in a linear manner at a uniform rate, and the addition time is controlled to be 8 min. The auxiliaries are added at once. Then the temperature is raised to 100°C at a rate of 1.0°C / min and dyed for 20 min.

[0107] The amount of acid dyes in the dyeing solution is 0.13% of the weight of the nylon fabric, specifically 0.1% for acid yellow dye, 0.03% for acid red dye, and 0.01% for acid blue dye. The concentration of auxiliaries in the dyeing solution is 2.5 g / L, specifically 1 g / L for softener in the bath, 1 g / L for acid leveling agent, and 0.5 g / L for organic acid-releasing agent. The weight ratio of the nylon fabric to be dyed to the dyeing solution is 1:10.

[0108] 2) Step 1) After dyeing, the temperature is lowered to 65℃ at a rate of 1.5℃ / min for color fixing. The color fixing time is 15min. During the color fixing process, a color fixing agent is added. The amount of color fixing agent added accounts for 3% of the weight of the nylon fabric to be dyed. It is added linearly at a uniform rate and the addition time is controlled to be 10min. After color fixing, the water is drained, washed and dried to obtain the dyed nylon fabric.

[0109] Comparative Example 2:

[0110] A method for one-bath dyeing and fixing of nylon fabrics (this method is Example 2 of invention patent CN110761089), the steps of which are as follows:

[0111] 1) After wetting the nylon fabric to be dyed at 50°C, add dyeing solution to it. The dyeing solution consists of acid dye and auxiliaries. The acid dye is added to the nylon fabric to be dyed in a linear manner at a uniform rate. The addition time is controlled to be 20 min. The auxiliaries are added at once. Then the temperature is raised to 100°C at a rate of 1.5°C / min and dyed for 25 min.

[0112] The amount of acid dyes in the dyeing solution is 2.17% of the weight of the nylon fabric, specifically 0.22% acid yellow dye, 0.45% acid red dye, and 1.5% acid blue dye. The concentration of auxiliaries in the dyeing solution is 2.5 g / L, specifically 1 g / L softener, 1 g / L acid leveling agent, and 0.5 g / L organic acid-releasing agent. The weight ratio of the nylon fabric to be dyed to the dyeing solution is 1:8.

[0113] 2) Step 1) After dyeing, the temperature is lowered to 70℃ at a rate of 1.2℃ / min for color fixing. The color fixing time is 25min. During the color fixing process, a color fixing agent is added. The amount of color fixing agent added accounts for 5% of the weight of the nylon fabric to be dyed. It is added linearly at a uniform rate and the addition time is controlled to be 15min. After color fixing, the water is drained, washed and dried to obtain the dyed nylon fabric.

[0114] Comparative Example 3:

[0115] A method for one-bath dyeing and fixing of nylon fabrics (this method is Example 3 of invention patent CN110761089), the steps of which are as follows:

[0116] 1) After wetting the nylon fabric to be dyed at 60°C, add dyeing solution to it. The dyeing solution consists of acid dye and auxiliaries. The acid dye is added to the nylon fabric to be dyed in a linear manner at a uniform rate. The addition time is controlled to be 40 min. The auxiliaries are added at once. Then the temperature is raised to 100°C at a rate of 1.5°C / min and dyed for 30 min.

[0117] The amount of acid dyes in the dyeing solution is 6.3% of the weight of the nylon fabric, specifically 0.8% acid yellow dye, 0.5% acid red dye, 1.0% acid blue dye, and 4.0% acid black dye. The concentration of auxiliaries in the dyeing solution is 1.5 g / L, specifically 1 g / L softener and 0.5 g / L organic acid-releasing agent. The weight ratio of the nylon fabric to be dyed to the dyeing solution is 1:12.

[0118] 2) Step 1) After dyeing, the temperature is lowered to 60℃ at a rate of 2℃ / min for color fixing. The color fixing time is 30min. During the color fixing process, a color fixing agent is added. The amount of color fixing agent added accounts for 8% of the weight of the nylon fabric to be dyed. It is added linearly at a uniform rate and the addition time is controlled to be 20min. After color fixing, the water is drained, washed and dried to obtain the dyed nylon fabric.

[0119] Comparative Example 4:

[0120] A method for one-bath dyeing and fixing of nylon fabrics (this method is Example 4 of invention patent CN110761089), the steps of which are as follows:

[0121] 1) After wetting the nylon fabric to be dyed at 35°C, add dyeing solution to it. The dyeing solution consists of acid dye and auxiliaries. The acid dye is added to the nylon fabric to be dyed in a linear manner at a uniform rate. The addition time is controlled to be 25 min. The auxiliaries are added at once. Then the temperature is raised to 80°C at a rate of 0.6°C / min and dyed for 50 min.

[0122] The amount of acid dyes in the dyeing solution is 1.1% of the weight of the nylon fabric, specifically 0.15% acid yellow dye, 0.2% acid red dye, and 0.75% acid blue dye. The concentration of auxiliaries in the dyeing solution is 2 g / L, specifically 0.8 g / L softener, 0.8 g / L acid leveling agent, and 0.4 g / L organic acid-releasing agent. The weight ratio of the nylon fabric to be dyed to the dyeing solution is 1:6.

[0123] 2) Step 1) After dyeing, the temperature is lowered to 50℃ at a rate of 1℃ / min for color fixing. The color fixing time is 10min. During the color fixing process, a color fixing agent is added. The amount of color fixing agent added accounts for 4% of the weight of the nylon fabric to be dyed. It is added linearly at a uniform rate and the addition time is controlled to be 7min. After color fixing, the water is drained, washed and dried to obtain the dyed nylon fabric.

[0124] Comparative Example 5:

[0125] A method for one-bath dyeing and fixing of nylon fabrics (this method is Example 5 of invention patent CN110761089), the steps of which are as follows:

[0126] 1) After wetting the nylon fabric to be dyed at 60°C, add dyeing solution to it. The dyeing solution consists of acid dye and auxiliaries. The acid dye is added to the nylon fabric to be dyed in a linear manner at a uniform rate. The addition time is controlled to be 60 min. The auxiliaries are added at once. Then the temperature is raised to 90°C at a rate of 1.2°C / min and dyed for 35 min.

[0127] The dyeing solution contains 9% acid dyes by weight of the nylon fabric, specifically 2.4% acid yellow, 1.5% acid red, 1.9% acid blue, and 3.2% acid black. The dyeing solution also contains 2 g / L auxiliaries, including 0.9 g / L softener, 0.6 g / L acid leveling agent, and 0.5 g / L organic acid-releasing agent. The weight ratio of the nylon fabric to be dyed to the dyeing solution is 1:15.

[0128] 2) Step 1) After dyeing, the temperature is lowered to 75℃ at a rate of 2.5℃ / min for color fixing. The color fixing time is 25min. During the color fixing process, a color fixing agent is added. The amount of color fixing agent added accounts for 6.5% of the weight of the nylon fabric to be dyed. It is added linearly at a uniform rate and the addition time is controlled to be 18min. After color fixing, the water is drained, washed and dried to obtain the dyed nylon fabric.

[0129] Table 3 lists the dyeing conditions and results for Comparative Examples 1-5 (Examples 1-5 of Invention Patent CN110761089). Table 4 is a COD analysis table of dyes and auxiliaries generated in the dye bath used to produce one ton of nylon fabric using the method of Comparative Examples 1-5 (Examples 1-5 of Invention Patent CN110761089). The method for calculating COD in the dyeing residue is as follows:

[0130] 1. The softener and leveling agent in the bath have no affinity for the fibers and remain completely in the residual liquid:

[0131] COD emissions = COD input

[0132] 2. The percentage of fixing agent applied to the fabric is approximately 50%, as calculated in Table 4 based on a 50% consumption rate:

[0133] COD emissions = 50% COD input

[0134] 3. Total COD emissions from dyeing residue:

[0135] Dye COD (100 - dyeing rate) + leveling agent COD + bath softener COD + 50% fixing agent COD + organic acid release agent COD.

[0136] Table 3. Dyeing conditions and results of fabrics prepared in Comparative Examples 1-5

[0137]

[0138] Table 4. COD analysis of dye and auxiliaries generated in the dye bath during the production of one ton of nylon fabric raw materials in Comparative Examples 1-5

[0139]

[0140] Based on the COD values ​​of the dyeing auxiliaries and dosages used in Comparative Examples 1-5 (Examples 1-5 of Invention Patent CN110761089), it is estimated that each ton of fabric will generate 22-42.6 kg of COD after dyeing, with black fabrics generating over 40 kg of COD. If we extrapolate from a medium-sized dyeing plant's annual production of 1,000 tons of black nylon-spandex fabric, using the dyeing technology disclosed in this method, the resulting COD of over 40 tons would directly generate 14 × 10⁻⁶ tons of COD after biochemical treatment. 6The greenhouse gas is methane; at the same time, it also requires the treatment of wastewater containing this amount of COD at the company's current treatment conditions of 0.3346 kg / kWh) which generates about 120,000 kWh of electricity. Assuming that 10,000 kWh of electricity generates 7.05 tons of carbon dioxide, then 1,000 tons of black nylon-methylene fabric will generate 84.24 tons of carbon dioxide.

[0141] Furthermore, the dyeing rates given in Comparative Examples 1-5 (Examples 1-5 of Invention Patent CN110761089) demonstrate that exhaustion dyeing cannot be achieved under acidic conditions. In particular, the 8% to 12% of unabsorbed dye remaining in black will combine with the remaining fixing agent to form suspended matter that is difficult to wash out. This not only increases the difficulty and amount of water required for subsequent washing but also affects the color fastness. Moreover, it fails to meet the requirements after soaking in water without fading.

[0142] Table 5 shows the dyeing depth and COD value at the same depth of the dyes used in this invention and those used in the prior art (invention patent CN110761089).

[0143] Table 5. Staining depth of different dyes and COD values ​​at the same staining depth.

[0144]

[0145] COD* represents the COD value of two sets of primary colors, converted to the same depth value according to the Integ value. The measured COD value of NHF-S yellow is 648, and that of Acid Yellow S-2G is 723. The Integ values ​​of NHF-S yellow are 3.77 and those of Acid Yellow S-2G are 4.124. Because NHF-S is lighter in color, the COD* value after conversion to the same depth value is higher than the measured value, and so on.

[0146] It is evident that the three primary colors selected in this invention have a significant advantage in color depth compared to the NHF-S primary colors at the same dyeing depth. The selected dyes have a higher color depth than the NHF-S type primary colors at the same dosage, which can save dosage and reduce COD, thus offering the advantage of being more low-carbon.

[0147] Example 5:

[0148] A high colorfastness black nylon-spandex knitted fabric dyeing process, comprising the following steps:

[0149] 1) The nylon-spandex knitted fabric to be dyed is continuously washed to remove oil stains and impurities from the fabric, then fed into the dyeing machine. It is moistened at 30°C for 5 minutes, and the dye liquor is slowly and evenly added for 20 minutes. After running for 5 minutes, calcium chloride is slowly and evenly added for 15 minutes. After running for 5 minutes, the temperature is raised to 55°C at a rate of 1°C / min and held for 10 minutes. Then the temperature is raised to 98°C at a rate of 1.5°C / min and dyed for 45 minutes. The ratio of calcium chloride to dye liquor is 1 g / L.

[0150] The ratio of the dye solution is:

[0151] Acid Yellow S-2G 0.2% (owf)

[0152] Acid Violet MB 0.2% (owf)

[0153] Acid Black MR 5.0% (owf);

[0154] 2) After dyeing, reduce the temperature to 80℃ at a rate of 1℃ / min and run for 20 minutes. Add 3% of the weight of the nylon-spandex knitted fabric to be dyed as a color-fixing agent and run for 30 minutes to finish color fixing.

[0155] 3) After the color fixation is completed, the temperature is lowered to 50℃, the liquid is drained, washed, and removed from the vat to obtain the dyed nylon-ammonia knitted fabric.

[0156] Comparative Example 6:

[0157] The steps are similar to those in Example 5, except that glacial acetic acid is used instead of calcium chloride, and the ratio of glacial acetic acid to dye solution is 1 g / L.

[0158] By comparing Comparative Example 6 and Example 5, and combining them... Figure 2 , Figure 3 , Figure 4 , Figure 5 It is evident that using calcium chloride as a dyeing auxiliary agent results in a higher dye exhaustion rate compared to glacial acetic acid. Under calcium chloride conditions, the dye is almost completely absorbed. Furthermore, the fabric obtained after further dyeing using the residual dyeing solution shows a significantly darker and more purplish color compared to the fabric treated with glacial acetic acid, while the fabric treated with calcium chloride is white and lighter. Ultimately, the fabric obtained using calcium chloride as a dyeing auxiliary agent exhibits a 4.137% greater depth of color compared to that obtained with glacial acetic acid, with almost all the purple dye being absorbed. This demonstrates that traditional dyeing methods using glacial acetic acid as a dyeing auxiliary agent are insensitive to the purple component, resulting in purple residue. This invention solves this problem by using calcium chloride as a dyeing auxiliary agent.

[0159] Comparative Example 7:

[0160] 1) In a room temperature yarn spray dyeing machine with pre-loaded raw yarn, wet the yarn with water at 30℃ for 10 minutes; add degreasing agent and ammonium sulfate and run for 10 minutes;

[0161] 2) Add the dye solution at a constant rate over 30 minutes and run for 10 minutes;

[0162] 3) Add calcium chloride solution at a constant rate over 20 minutes and run for 10 minutes;

[0163] 4) Increase the temperature to 55℃ at a rate of 1℃ / min, keep it at that temperature for 10 minutes, and then increase the temperature to 98℃ at a rate of 1.5℃ / min for staining for 40 minutes.

[0164] 5) Then open the machine cover and let it cool naturally to 80℃. After running for 10 minutes, add the color-fixing agent evenly and fix the color at 80℃ for 20 minutes, then drain the liquid.

[0165] 6) Infuse water, wash with clean water at 60℃ for 10 minutes, then drain;

[0166] 7) Add water, soften with softener at room temperature for 15 minutes, drain and dehydrate to obtain the product name: black imitation mink knitted yarn.

[0167] The formula for the dyeing solution is: dyeing bath ratio 1:6.

[0168]

[0169]

[0170] Note: The greige yarn contains 2.5-3.0% spinning oil. This process uses an anionic nonionic degreasing agent and an anionic fixing agent, so that it can be carried out in the same bath as the dyeing.

[0171] Comparative Example 8:

[0172] The steps are similar to those of Comparative Example 7, except that glacial acetic acid is used instead of calcium chloride, and the ratio of glacial acetic acid to dye solution is 1 g / L.

[0173] Combined with Examples 7 and 8 Figure 6 , Figure 7 It is evident that the black nylon feather yarn produced using calcium chloride as a dyeing auxiliary agent fades significantly less than the black nylon feather yarn produced using glacial acetic acid as a dyeing auxiliary agent when soaked in 95℃ hot water and 95℃ hot water + soaping agent. Figure 8 It can be seen that the black nylon-spandex fabric did not show any signs of fading when soaked in 50℃ hot water with laundry detergent, indicating that the fabric produced by this invention can meet the customer's requirement of not fading when soaked in water; the above unfixed feather yarn and nylon-spandex fabric both showed good results when soaked in water. Among them, the nylon-spandex fabric, due to the influence of spandex staining, still needs to be fixed in the same bath even though it shows complete dye absorption, but the amount of fixing agent is ≤3%.

[0174] Furthermore, it can be seen that the present invention can also be extended to the dyeing process of dark nylon fabrics (such as yarns) that can be covered by the above three primary colors. In yarn package dyeing and skein dyeing of black and extra dark colors, it is possible to obtain color depth and high color fastness that cannot be achieved by using acetic acid and organic acid-releasing dye baths, and the color will not fade when soaked in water. Among them, the amount of calcium chloride used in yarn dyeing is preferably 1-2 g / L (for special dark black package yarns). When the amount of calcium chloride is greater than 2 g / L, there is no obvious effect. The amount of calcium chloride used as a dyeing auxiliary agent in the dyeing of nylon fabrics with neutral dyes can be gradually reduced according to the color from dark to medium. The amount of calcium chloride can be gradually reduced from 1 g / L to 0.2 g / L.

[0175] Table 6 shows the maximum solubility of sodium chloride, sodium sulfate, ammonium sulfate, and calcium chloride in water at 100℃ and the pH value of a 1 g / L aqueous solution at 100℃.

[0176] Table 6. Maximum solubility of sodium chloride, sodium sulfate, ammonium sulfate, and calcium chloride in water at 100℃ and pH value of 1 g / L aqueous solution at 100℃.

[0177]

[0178]

[0179] Neutral dyes have a high affinity for nylon fibers. Choosing neutral dyeing conditions is beneficial for the even dyeing of neutral dyes. Dyeing can be promoted by adding electrolytes that are completely ionized in water to the neutral dye bath. In the existing technology, 1-3% of the fabric weight of anhydrous sodium sulfate and 1g / l of ammonium sulfate are usually added to the dye bath to form a neutral dye bath.

[0180] As shown in Table 6, calcium chloride has the highest solubility in water at 100℃, and its aqueous solution is weakly acidic. Compared with neutral dyeing auxiliaries, calcium chloride aqueous solution is conducive to the protonation of trace amino groups in nylon fibers, thus exhibiting a strong dyeing-promoting effect. On the other hand, the hydrated ions of calcium chloride can loosen the fiber structure, which is conducive to the diffusion of dye into the fiber interior. At the same time, the accessibility of dye increases, and the adsorption sites in the fiber are fully exposed, effectively promoting the formation of various bonds (electrostatic, van der Waals, hydrogen bonds, and hydrophobic interactions) between acid dyes and nylon 6. Thus, the special role of calcium chloride as a dyeing auxiliary for neutral dyes endows black nylon fabrics with excellent color fastness, especially meeting customers' eager expectations for colorfastness after soaking in water.

[0181] The above provides a detailed description of the high colorfastness black nylon-spandex knitted fabric impregnation dyeing process provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments 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 low-carbon dyeing process for high colorfastness nylon-spandex knitted fabrics, characterized in that, The process includes the following steps: 1) Add dye liquor and dyeing auxiliary agent to the nylon-spandex knitted fabric to be dyed, first heat to 40-60℃ and keep warm for 10-30 minutes, then heat to 80-100℃ and dye for 30-50 minutes. The dyeing auxiliary agent is calcium chloride. The weight ratio of the nylon-spandex knitted fabric to the dye liquor is 1:6-20; 2) After dyeing in step 1), the fabric is cooled to 60-80℃ for color fixing, and a color fixing agent is added during the color fixing process; 3) After the color fixation is completed in step 2), the fabric is cooled to 40-50℃, drained, washed, and removed from the vat to obtain the dyed nylon-spandex knitted fabric. The dyeing solution is prepared with acid dyes, including one or more of CI Acid Yellow 220, CI Acid Violet 90, CI Acid Blue 193 and CI Acid Black 172, and the amount of acid dye used is 2.0-8.0% (owf). The ratio of the dyeing auxiliary agent to the dyeing solution is 0.2-2 g / L.

2. The low-carbon dyeing process for high colorfastness nylon-spandex knitted fabrics according to claim 1, characterized in that: The amount of acid dye used includes: CI Acid Yellow 220 0-3.0% (owf) CI Acid Violet 90 0-4.0% (owf) CI Acid Blue 193 0-5.0% (owf) CI Acid Black 172 0-8.0% (owf).

3. The low-carbon dyeing process for high colorfastness nylon-spandex knitted fabrics according to claim 1, characterized in that: Before adding the dye solution, the nylon-spandex knitted fabric to be dyed needs to be moistened. The humidification temperature is 20-40℃. The wetting time is 10-20 minutes.

4. The low-carbon dyeing process for high colorfastness nylon-spandex knitted fabrics according to claim 3, characterized in that: Before the dyeing process, the nylon-spandex knitted fabric needs to be continuously washed to remove oil stains and impurities from the fabric.

5. The low-carbon dyeing process for high colorfastness nylon-spandex knitted fabrics according to claim 1, characterized in that: In step 1), the heating conditions are to first raise the temperature to 55°C at 1°C / min and hold it for 10 min, and then raise the temperature to 98°C at 1.5°C / min. In step 2), the temperature is lowered to 80°C at 1°C / min.

6. The low-carbon dyeing process for high colorfastness nylon-spandex knitted fabrics according to claim 1, characterized in that: The staining time described in step 1) is 30-45 min.

7. The low-carbon dyeing process for high colorfastness nylon-spandex knitted fabrics according to claim 1, characterized in that: The amount of color-fixing agent added in step 2) is 2-3% of the mass of the nylon-spandex knitted fabric to be dyed. The fixing agent is added at a constant rate 20 minutes after the start of the fixing process. The color-fixing time is 20-30 minutes.

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