Polyester-cotton blended knitted fabric and one-bath dyeing method thereof

Abstract

The present application relates to the technical field of weaving and dyeing and finishing, and particularly relates to a polyester-cotton blended knitted fabric and a one-bath dyeing method thereof. The pretreated polyester-cotton blended knitted fabric is subjected to one-bath dyeing, the bath ratio is 1:8-10, the dyeing solution contains sodium sulfate, disperse dye, reactive dye and balancing agent, then the fabric is fixed in a two-component fixing solution after two soaping, the amount of auxiliaries and water is saved, the wastewater discharge and process energy consumption are greatly reduced; meanwhile, the color difference of the dyed fabric is significantly reduced, the wet rubbing fastness of the fabric is effectively improved, and the soaping fastness of the six fibers is ensured at a high level; the core fixing mechanism of the two-component fixing agent is synergistic crosslinking and interface stabilization, and the dye migration is reduced.

Description

Technical Field

[0001] This invention relates to the field of weaving and dyeing technology, specifically to a polyester-cotton blended knitted fabric and its one-bath dyeing method. Background Technology

[0002] Polyester-cotton blended knitted fabrics are knitted fabrics made by knitting with polyester-cotton blended yarn as one or more of the yarns. The dyeing properties of polyester and cotton fibers are very different, so two dyes are generally used to dye the two fibers separately. Polyester usually uses disperse dyes, while cotton often uses reactive dyes with better fastness. The traditional process is the two-bath method.

[0003] The two-bath dyeing process using disperse and reactive dyes typically involves first dyeing polyester with disperse dyes, followed by a reduction wash, and then overdyeing cotton with reactive dyes. This process uses a large amount of water and requires a variety of auxiliaries. Reactive dye fixation should be carried out in an alkaline bath. However, in an alkaline bath, at higher temperatures, many disperse dyes will undergo hydrolysis and reduction degradation, and some polyester fibers, such as PLA fibers, will also suffer hydrolytic damage. Therefore, disperse dyes are best used in a weakly acidic bath, where the pH difference between the two dyes is significant.

[0004] Currently, a one-bath dyeing process for polyester-cotton blended knitted fabrics is gradually emerging. For example, a one-bath dyeing process for polyester-cotton disclosed in Chinese patent document (CN116905251A) includes pre-dyeing treatment, dyeing, and post-dyeing treatment steps. The dyeing step includes the following steps: adding alkali-resistant disperse dye, high-temperature resistant reactive dye, and dyeing auxiliaries to prepare a dye liquor; adding fabric to the dye liquor, heating to 120-130℃, holding at that temperature for 30-60 minutes, and then cooling to 65-80℃; dyeing with both dyes simultaneously, thereby reducing the time spent in the dyeing process. However, the color difference of the dyed fabric obtained by this one-bath method for polyester-cotton still reaches 0.5 or higher, and the wet rubbing fastness is relatively low, with some fibers failing to reach grade 4 or higher in soap washing fastness. Summary of the Invention

[0005] The purpose of this invention is to provide a one-bath dyeing method for polyester-cotton blended knitted fabrics, which can reduce color difference and effectively improve the color fastness to washing and rubbing of the fabric.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A one-bath dyeing method for polyester-cotton blend knitted fabrics includes the following steps:

[0008] The pretreated polyester-cotton blended knitted fabric was dyed in one bath with a liquor ratio of 1:8-10. The dyeing liquor contained sodium sulfate, disperse dye, reactive dye, and balancing agent. The temperature was raised to 130±2℃ and kept at that temperature for 50±10 min. Then the temperature was lowered to 65±5℃ for a hot wash.

[0009] Add 0.5g / L-1.0g / L of neutral soap at a bath ratio of 1:8-10. Perform a first soap wash at 95±2℃ for 20±5 minutes, drain the liquid, add another 0.5g / L-1.0g / L of neutral soap at 85±2℃ for a second soap wash for 20±5 minutes, drain the liquid, and rinse once with cold water.

[0010] Finally, fix the color in the two-component fixing solution at 40±2℃ for 20±5 min, then dehydrate, dry, and set.

[0011] The balancing agent comprises the following components by mass fraction: 3%-6% pH shifting agent, 1%-3% polyacrylate dispersant, 15%-25% anionic penetrant, and the balance being water.

[0012] Preferably, the order in which the components in the dye solution are added is sodium sulfate, reactive dye, disperse dye, and balancing agent.

[0013] Preferably, the amount of sodium sulfate used is 130g / L-150g / L.

[0014] Preferably, the dosage of the balancing agent is 1.5 g / L to 4.0 g / L.

[0015] Preferably, the heating rate to 130±2℃ is 2.5℃ / min-3.5℃ / min.

[0016] Preferably, the cooling rate to 65±5℃ is 1.0℃ / min-2.0℃ / min.

[0017] Preferably, the two-component fixing solution contains 2 g / L-4 g / L of two-component fixing agent, with a pH value of 6.5-7.5. The two-component fixing agent is composed of an epoxy quaternary ammonium salt compound, siloxane-grafted maleic anhydride polybutadiene, and a nonionic penetrant, with a mass ratio of 1:0.70-0.85:0.40-0.60.

[0018] The present invention also provides a polyester-cotton blended knitted fabric, which is prepared by the above-mentioned one-bath dyeing method. The fabric has a double rib knitting structure, with six rows forming a complete structure. Rows 1, 2, 4, and 5 are made of polyester-cotton blended yarn, while rows 3 and 6 are made of combed cotton. In particular, rows 1 and 5 are knitted with low-heel stitches to form loops, rows 2 and 4 are knitted with high-heel stitches to form loops, rows 3 are knitted with low-heel stitches to form loops and knitted with low-heel stitches to form loops, and rows 6 are knitted with high-heel stitches to form loops.

[0019] Preferably, the polyester-cotton blended yarn has a polyester-cotton blending ratio of 65 / 35 and a yarn count of 40.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] In this invention, a balancing agent is used in the one-bath dyeing step. Its main components are: polyacrylate dispersant, pH shifting agent, and anionic penetrant. The pH shifting agent dynamically adjusts the pH balance of the dye bath to ensure that different pH values ​​are maintained at different temperatures, thus ensuring that reactive dyes and disperse dyes are dyed at the appropriate pH value. The polyacrylate dispersant encapsulates the disperse dye particles, preventing them from agglomerating and precipitating in the alkaline bath and reducing contamination of cotton fibers. The anionic penetrant promotes the swelling of cotton fibers, accelerates the penetration of reactive dyes, and assists in the high-temperature dispersion of disperse dyes.

[0022] The present invention employs a process of first performing two soaping washes followed by a second fixation process with a two-component fixative, which significantly reduces the color difference of dyed fabrics and effectively improves the wet rubbing fastness of the fabrics, while ensuring that the soaping fastness of the six-fiber fabrics remains at a high level. The main components of the two-component fixing agent of this invention are epoxy quaternary ammonium salt compound and siloxane-grafted maleic anhydride polybutadiene. Its core fixing mechanism is synergistic crosslinking and interfacial stabilization, which reduces dye migration. After one-bath dyeing of polyester and cotton, residual dye ions exist on the fiber surface. The epoxy quaternary ammonium salt compound captures and fixes the dye on the fiber surface through electrostatic adsorption, reducing the loss during direct washing. The anhydride in the siloxane-grafted maleic anhydride polybutadiene undergoes a crosslinking reaction with the hydroxyl and amino groups in the fiber or dye and opens the ring to generate carboxyl groups. The carboxyl groups react with the epoxy groups in the epoxy quaternary ammonium salt compound to fix the dye on the fiber. At the same time, the non-ionic penetrant reduces the interfacial tension, allowing the siloxane-grafted maleic anhydride polybutadiene, epoxy quaternary ammonium salt compound and dye to penetrate more evenly into the fiber interior, forming a stable coating layer. At the same time, the use of siloxane-grafted maleic anhydride polybutadiene avoids the fabric stiffness problem caused by traditional single-component fixing agents.

[0023] In addition, compared with the traditional two-bath dyeing process, the one-bath dyeing process of this invention saves on the amount of auxiliary agents and water, such as caustic soda, scouring agent, hydrogen peroxide stabilizer, glacial acetic acid, sodium hydrosulfite, caustic soda, glacial acetic acid, etc., which greatly reduces wastewater discharge and process energy consumption. Attached Figure Description

[0024] Figure 1 This is a process curve diagram of one-bath dyeing of polyester-cotton blended knitted fabrics according to the present invention. Detailed Implementation Example 1

[0025] This embodiment provides a polyester-cotton blended knitted fabric with a double rib knitting structure. The structure consists of six rows forming a complete knit. Rows 1, 2, 4, and 5 use 40-count polyester-cotton blended yarn (65 / 35), while rows 3 and 6 use 26S / 1 combed cotton. Rows 1 and 5 are knitted with low-heel stitches in the knit and purl pattern to form loops. Rows 2 and 4 are knitted with high-heel stitches in the knit and purl pattern to form loops. Row 3 is knitted with low-heel stitches in the knit and purl pattern, and row 6 is knitted with high-heel stitches in the knit and purl pattern.

[0026] The one-bath dyeing method for polyester-cotton blended knitted fabrics specifically includes the following steps:

[0027] One-bath dyeing: The pretreated polyester-cotton blended knitted fabric is subjected to one-bath dyeing at a liquor ratio of 1:10. The fabric is fed in, and 150 g / L sodium sulfate, reactive dyes, disperse dyes, and 2 g / L balancing agent are added sequentially. The temperature is increased to 130°C at 3°C / min and held for 45 min, followed by a hot wash at 2°C / min to 65°C. The balancing agent comprises the following components by mass fraction: 3%-6% pH slip agent, 1%-3% polyacrylate dispersant, 15%-25% anionic penetrant, and the balance being water. The reactive and disperse dyes are specifically: Disperse Yellow Brown RYF-3R 0.45%, Disperse Ruby RYF-B 0.3%, Disperse Black RYF-B 1.8%, Reactive Red 0.4%, Reactive Yellow 0.25%, and Reactive Black 6.0%.

[0028] First soaping: Add 0.7 g / L of neutral soaping agent at a bath ratio of 1:10. Its main component is maleic acid acrylic acid copolymer. Soap for 20 minutes at 95℃ and then drain.

[0029] Second soaping: Add 0.8 g / L of neutral soaping agent at a bath ratio of 1:10. Its main component is maleic acid acrylic acid copolymer. Perform a second soaping at 85°C for 20 minutes, drain the liquid, and rinse once with cold water.

[0030] Fixation: Fix the color at 40°C for 20 min in a two-component fixing solution. The two-component fixing solution contains 2.0 g / L of two-component fixing agent and has a pH of 6.5. The two-component fixing agent is composed of an epoxy quaternary ammonium salt compound, siloxane-grafted maleic anhydride polybutadiene, and a nonionic penetrant in a mass ratio of 1:0.8:0.5. The epoxy quaternary ammonium salt compound is specifically 2,3-epoxypropyltrimethylammonium chloride, and the nonionic penetrant is mainly composed of an ethoxylated surfactant.

[0031] Dehydration, drying, and shaping. Example 2

[0032] This embodiment provides a polyester-cotton blended knitted fabric with a double rib knitting structure. The structure consists of six rows forming a complete knit. Rows 1, 2, 4, and 5 use 40-count polyester-cotton blended yarn (65 / 35), while rows 3 and 6 use 26S / 1 combed cotton. Rows 1 and 5 are knitted with low-heel stitches in the knit and purl pattern to form loops. Rows 2 and 4 are knitted with high-heel stitches in the knit and purl pattern to form loops. Row 3 is knitted with low-heel stitches in the knit and purl pattern, and row 6 is knitted with high-heel stitches in the knit and purl pattern.

[0033] The one-bath dyeing method for polyester-cotton blended knitted fabrics specifically includes the following steps:

[0034] One-bath dyeing: The pretreated polyester-cotton blended knitted fabric is subjected to one-bath dyeing at a liquor ratio of 1:10. The fabric is fed in, and 150 g / L sodium sulfate, reactive dyes, disperse dyes, and 2.5 g / L balancing agent are added sequentially. The temperature is increased to 130°C at 3°C / min and held for 45 min, followed by a hot wash at 2°C / min to 65°C. The balancing agent comprises the following components by mass fraction: 3%-6% pH slip agent, 1%-3% polyacrylate dispersant, 15%-25% anionic penetrant, and the balance being water. The reactive and disperse dyes are specifically: Disperse Yellow Brown RYF-3R 0.45%, Disperse Ruby RYF-B 0.3%, Disperse Black RYF-B 1.8%, Reactive Red 0.4%, Reactive Yellow 0.25%, and Reactive Black 6.0%.

[0035] First soap wash: Add 0.6 g / L of neutral soap detergent at a bath ratio of 1:10. Its main component is maleic acid acrylic acid copolymer. Soap wash for 20 minutes at 95℃ and then drain.

[0036] Second soaping: Add 1.0 g / L of neutral soaping agent at a bath ratio of 1:10. Its main component is maleic acid acrylic acid copolymer. Soap for 20 minutes at 85℃, drain the liquid, and rinse once with cold water.

[0037] Fixation: Fix the color at 40°C for 15 min in a two-component fixing solution. The two-component fixing solution contains 3 g / L of two-component fixing agent and has a pH of 6.5. The two-component fixing agent is composed of an epoxy quaternary ammonium salt compound, siloxane-grafted maleic anhydride polybutadiene, and a nonionic penetrant in a mass ratio of 1:0.8:0.5. The epoxy quaternary ammonium salt compound is specifically 2,3-epoxypropyltrimethylammonium chloride, and the nonionic penetrant is mainly composed of an ethoxylated surfactant.

[0038] Dehydration, drying, and shaping.

[0039] Comparative Example 1

[0040] The only difference between this comparative example and Example 1 above is the absence of a second soaping step.

[0041] Comparative Example 2

[0042] The only difference between this comparative example and Example 1 above is that a 2.0 g / L fixing agent, which is a compound of polyamine polymer and surfactant, is used in the fixing step, the fixing temperature is 40°C, and the fixing time is 25 min.

[0043] The physical properties of the fabrics from Examples 1-2 and Comparative Examples 1-2 after fixing were tested, and the results are shown in Table 1. Specifically: the color difference ΔE of the dyed fabrics before and after soaping was measured using a Datacolor i7 computer colorimeter; the color fastness to soaping was determined according to GB / T 3921.3-2008 "Textiles - Tests for Color Fastness to Soaping"; the color fastness to rubbing was determined according to CB / T3920-2008 "Textiles - Tests for Color Fastness to Rubbing"; and the tests were conducted according to GB / T19976-2005 "Textiles - Breaking Strength Test (Steel Ball Test)," with three measurements taken and the average value recorded.

[0044] Table 1: Test Results of Examples 1-2 and Comparative Examples 1-2 of the Present Invention

[0045]

[0046] The foregoing has shown and described the basic principles, main features and advantages of this invention. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of this invention. Various changes and modifications can be made to this invention without departing from the spirit and scope of this invention. All such changes and modifications fall within the scope of this invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A one-bath dyeing method for polyester-cotton blend knitted fabrics, characterized in that, Includes the following steps: The pretreated polyester-cotton blended knitted fabric was dyed in one bath with a liquor ratio of 1:8-10. The dye liquor contained sodium sulfate, disperse dye, reactive dye, and balancing agent. The temperature was raised to 130±2℃ and kept at that temperature for 50±10 min. Then the temperature was lowered to 65±5℃ for a hot wash. Add 0.5g / L-1.0g / L of neutral soap at a bath ratio of 1:8-10. Perform a first soap wash at 95±2℃ for 20±5 minutes, drain the liquid, add another 0.5g / L-1.0g / L of neutral soap at 85±2℃ for a second soap wash for 20±5 minutes, drain the liquid, and rinse once with cold water. Finally, fix the color in the two-component fixing solution at 40±2℃ for 20±5 min, then dehydrate, dry, and set. The balancing agent comprises the following components by mass fraction: 3%-6% pH shifting agent, 1%-3% polyacrylate dispersant, 15%-25% anionic penetrant, and the balance being water; The two-component fixing solution contains 2g / L-4g / L of a two-component fixing agent, which is composed of an epoxy quaternary ammonium salt compound, siloxane-grafted maleic anhydride polybutadiene, and a nonionic penetrant.

2. The one-bath dyeing method for polyester-cotton blended knitted fabrics according to claim 1, characterized in that: The order in which the components in the dye solution are added is sodium sulfate, reactive dye, disperse dye, and balancing agent.

3. The one-bath dyeing method for polyester-cotton blended knitted fabrics according to claim 2, characterized in that: The amount of sodium sulfate used is 130g / L-150g / L.

4. The one-bath dyeing method for polyester-cotton blended knitted fabrics according to claim 2, characterized in that: The dosage of the balancing agent is 1.5 g / L to 4.0 g / L.

5. The one-bath dyeing method for polyester-cotton blended knitted fabrics according to claim 1, characterized in that: The heating rate to 130±2℃ is 2.5℃ / min-3.5℃ / min.

6. The one-bath dyeing method for polyester-cotton blended knitted fabrics according to claim 1, characterized in that: The cooling rate to 65±5℃ is 1.0℃ / min-2.0℃ / min.

7. A polyester-cotton blended knitted fabric, characterized in that: The polyester-cotton blended knitted fabric is prepared by a one-bath dyeing method as described in any one of claims 1 to 6. The fabric has a double rib knitting structure, with six rows forming a complete structure. Rows 1, 2, 4, and 5 use polyester-cotton blended yarn, while rows 3 and 6 use combed cotton. In particular, rows 1 and 5 are knitted with low-heel stitches to form loops, rows 2 and 4 are knitted with high-heel stitches to form loops, rows 3 are knitted with low-heel stitches and knitted with low-heel stitches to form loops, and rows 6 are knitted with high-heel stitches and knitted with high-heel stitches to form loops.

8. The polyester-cotton blended knitted fabric according to claim 7, characterized in that: The polyester-cotton blended yarn has a polyester / cotton blend ratio of 65 / 35 and a yarn count of 40.

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