Short process dyeing process for anti-wrinkle polyester-cotton

Abstract

The present application relates to the technical field of dyeing process, in particular to a short process anti-wrinkle polyester-cotton dyeing process, which comprises the following steps: preparing thermally induced phase change catalytic microcapsules with a melting point of 140-150 DEG C; mixing disperse dyes, reactive dyes containing phosphonic acid groups, polycarboxylic acid cross-linking agents and the microcapsules to prepare a dormant state one-bath working solution with a pH of 6.0-6.5; impregnating the polyester-cotton fabric with the working solution and pre-drying at 100-120 DEG C; then high-temperature baking at 170-190 DEG C, the microcapsule wall material is melted and releases catalyst in situ, triggering cross-linking reaction and heat-dyeing at the same time; finally, washing aftertreatment is carried out. The present application builds an asynchronous catalytic system through phase change isolation, solves the problems of premature solidification of cross-linking in one-bath process hindering dye penetration and fiber damage caused by acidic liquid, and significantly improves the dyeing depth and fabric breaking strength retention rate.

Description

Technical Field

[0001] This invention relates to the field of dyeing technology, and more specifically, to a short-process dyeing process for wrinkle-resistant polyester-cotton blends. Background Technology

[0002] Conventional dyeing and wrinkle-resistant finishing of polyester-cotton blended fabrics are usually performed as separate processes. Traditionally, a two-bath or two-step method is employed: first, the polyester component is dyed with disperse dyes under low temperature and weakly acidic conditions (pH 4-5); after reduction washing, the cotton component is then dyed with reactive dyes under alkaline conditions (pH 10-11). After the dyeing process, wrinkle-resistant finishing is performed separately, involving immersing the fabric in a working solution containing resin or polycarboxylic acid crosslinking agents and then baking and crosslinking at high temperature. This step-by-step process is lengthy, consumes large amounts of water, and is energy-intensive.

[0003] To shorten the processing flow, existing technologies have attempted to develop a combined dyeing and finishing process. However, this combined process presents chemical environment conflicts in practical applications. Conventional reactive dyes require an alkaline environment for fixation, while the dyeing of disperse dyes and the crosslinking reaction of polycarboxylic acid anti-wrinkle agents require weakly acidic conditions. Direct mixing can lead to the hydrolysis and inactivation of reactive dyes or the deactivation of the crosslinking system.

[0004] To address the aforementioned pH conflict, some existing technologies employ a compounding of dyes that can react under weakly acidic conditions (such as phosphonic acid-based dyes) with disperse dyes, polycarboxylic acid crosslinking agents, and catalysts (such as sodium hypophosphite) to simultaneously complete dyeing and crosslinking in a single weakly acidic bath. However, in this simultaneous reaction system, the catalyst is in a free and active state during the working solution stage. During the padding and low-temperature penetration stages, the free catalyst can cause premature hydrolysis of the crosslinking agent, reducing the final crosslinking efficiency. Simultaneously, immersing and heating the fabric in a working solution containing an acidic catalyst can lead to acid-induced degradation of the cotton fibers, resulting in a decrease in the fabric's breaking strength.

[0005] Furthermore, during the heating process of the synchronous system, the diffusion of dye into the fiber interior and the curing of crosslinking agent on the fiber surface occur simultaneously. The prematurely formed crosslinking network creates steric hindrance, hindering the further penetration of dye molecules into the amorphous regions of the fiber, resulting in insufficient dyeing depth, increased surface floating dye, and reduced color fastness of the final fabric.

[0006] Current technologies have not yet solved the problem of premature initiation of the catalytic system in the co-bath working solution. How to achieve stable coexistence of various chemical components in a single working solution, avoid fiber damage during the penetration stage, and precisely trigger the cross-linking reaction at high-temperature process nodes, thereby eliminating the physical spatial contradiction between dyeing diffusion and cross-linking curing, is a technical problem that needs to be solved to achieve high-quality co-bath processing of polyester-cotton fibers in a short process. Summary of the Invention

[0007] The purpose of this invention is to provide a wrinkle-resistant short-process dyeing process for polyester and cotton to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides a wrinkle-resistant polyester-cotton short-process dyeing process, comprising the following steps: S1. Preparation of thermo-induced phase change catalytic microcapsules: Sodium hypophosphite catalyst is ground and pulverized; polyamide hot melt resin or high-density modified polyethylene wax with a melting temperature between 140℃ and 150℃ is selected as the wall material and heated to complete melting; the pulverized catalyst is added as the core material to the molten wall material, and a nonionic surfactant is added to control the mass ratio of core material to wall material to be 1:2-1:4; melt dispersion is carried out under high-speed shear conditions of 6000-8000 r / min for 15-20 minutes, followed by spray condensation granulation, filtration and drying to obtain thermo-induced phase change catalytic microcapsules with a particle size distribution of 1-3 μm; S2. Preparation of dormant co-bath working solution: Disperse dye, reactive dye, polycarboxylic acid crosslinking agent and the thermo-induced phase change catalytic microcapsules prepared in S1 are added to deionized water and mixed evenly. The pH value is adjusted to 6.0-6.5 using glacial acetic acid and sodium acetate buffer to obtain the dormant co-bath working solution. S3. Padding and Medium-Temperature Penetration: The pretreated polyester-cotton fabric is immersed in a dormant working solution for two dips and two pads, with the padding rate controlled at 65%-75%. The fabric is then placed in an infrared pre-drying device at 100℃-120℃ for pre-drying until the fabric moisture content is 15%-20%. S4. High-temperature in-situ release and cross-linking: The pre-dried fabric is sent into a hot air baking equipment and baked at 170℃-190℃ for 90-120 seconds. Under this temperature condition, the wall material of the thermo-induced phase change catalytic microcapsules attached to the fiber gaps and amorphous regions undergoes thermo-melting, releasing the core catalyst in situ, and simultaneously triggering the dehydration esterification cross-linking reaction of the polycarboxylic acid cross-linking agent with the cotton fiber, as well as the thermo-melting dyeing of the polyester fiber by the disperse dye. S5. Post-treatment: After baking, the fabric is washed in 40℃ warm water, then in 70-80℃ hot soaping with soaping agent to remove floating color and unreacted substances, and finally washed with cold water and dried.

[0009] Furthermore, in S2, the reactive dye is a reactive dye containing phosphonic acid groups; the polycarboxylic acid crosslinking agent is a mixture of butanetetracarboxylic acid and citric acid in a mass ratio of 1:1 to 1:2.

[0010] Furthermore, the mass concentrations of the main effective components in the dormant co-bath working solution are as follows: disperse dye 1-5 g / L, reactive dye 2-8 g / L, polycarboxylic acid crosslinking agent 30-60 g / L, and thermo-induced phase change catalytic microcapsules 15-30 g / L.

[0011] Furthermore, the dormant working solution also contains 1-2 g / L of electrolyte-resistant isomeric tridecyl alcohol polyoxyethylene ether penetrant and 10-20 g / L of polyacrylic acid anti-migration agent.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: In this wrinkle-resistant polyester-cotton short-process dyeing process, microcapsules with specific particle sizes (1-3 μm) and specific phase transition thresholds (140℃-150℃) are prepared by melt-condensation method. The small particle size ensures that the capsules can penetrate into the fiber gaps with the dye solution. In the medium-temperature penetration stage of S3 (100℃-120℃), the temperature is lower than the melting point of the microcapsule wall material. The working solution is in a dormant state without free catalyst, and the polycarboxylic acid crosslinking agent does not undergo crosslinking reaction. This allows the dye molecules to fully diffuse and penetrate into the amorphous region of the fiber in a physical state without steric hindrance. This solves the defect of the crosslinking network forming a film in advance and blocking the dye in the traditional same-bath process.

[0013] Secondly, this process sets the pH value of the working solution in the same bath at a near-neutral and mild environment of 6.0-6.5, avoiding acid-induced degradation of cotton cellulose caused by acid catalysts during the long process of liquid immersion and medium-temperature pre-drying. When the process enters the high-temperature baking stage of 170℃-190℃, the surface temperature of the fabric exceeds the melting point threshold of polyamide / polyethylene wax wall material. The microcapsules rapidly disintegrate inside the fiber, releasing a high concentration of sodium hypophosphite in situ. The esterification cross-linking network is efficiently constructed within 90-120 seconds. This dual control in time (asynchronous reaction) and space (in situ release) significantly improves the tensile strength retention rate of the treated fabric.

[0014] Meanwhile, this solution combines disperse dyeing, reactive dyeing, and resin anti-wrinkle function into a single bath, and uses a microscopic phase change release mechanism to replace the complex macroscopic process segmentation. The entire process can be put into production without replacing the existing continuous dyeing equipment in the printing and dyeing plant. The total water consumption is reduced by about 50% compared with the traditional process, which has great industrial promotion and practical value. Attached Figure Description

[0015] Figure 1 This is an overall flowchart of Embodiment 1 of the present invention. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1: A short-process dyeing technology for wrinkle-resistant polyester-cotton, such as Figure 1 As shown, it includes the following steps: S1. Preparation of thermo-induced phase change catalytic microcapsules: Sodium hypophosphite was ground in a ball mill until the D50 particle size was less than 0.5 μm. 30 g of polyamide hot melt resin with a melting temperature of 145 °C was weighed as the wall material and heated to 160 °C to completely melt it. 10 g of the pulverized sodium hypophosphite was added as the core material to the molten wall material, followed by 0.5 g of nonionic surfactant (Pingpingjia O, fatty alcohol polyoxyethylene ether). The mass ratio of core material to wall material was controlled at 1:3. The mixture was dispersed in a high-speed shear emulsifier at 7000 r / min for 15 minutes, rapidly spray-dried and condensed into granules, filtered, and dried in a vacuum drying oven to obtain thermo-induced phase change catalytic microcapsules with an average particle size of 2.1 μm.

[0018] S2. Preparation of the dormant working solution: Add the following components sequentially to deionized water and mix thoroughly: Disperse dye (Disperse Ruby S-2GFL): 3g / L; Reactive dyes containing phosphonic acid groups: 5 g / L; Polycarboxylic acid crosslinking agent (butanetetracarboxylic acid and citric acid in a mass ratio of 1:1): 45g / L; S1 prepared thermally induced phase change catalytic microcapsules: 20 g / L; Electrolyte-resistant isomeric tridecyl alcohol polyoxyethylene ether penetrant: 1.5 g / L; Polyacrylic acid-based anti-migratory agent: 15g / L; The pH of the above mixture was adjusted to 6.2 using glacial acetic acid and sodium acetate buffer to obtain the dormant co-bath working solution.

[0019] S3. Padding and Medium-Temperature Penetration: The polyester-cotton blended fabric (polyester / cotton mass ratio 65 / 35) that has undergone conventional pretreatment is immersed in the above-mentioned dormant co-bath working solution and subjected to two dips and two pads on a continuous pad dyeing machine. The roller pressure is set to control the fabric padding rate at 70%. The fabric is then sent to an infrared pre-drying oven and pre-dried at 110°C until the fabric moisture content drops to 18%.

[0020] S4. High-temperature in-situ release and cross-linking: The pre-dried fabric is sent into a hot air baking machine and continuously baked at 180°C for 100 seconds. During this stage, the microcapsule wall material melts, sodium hypophosphite is released in situ, and the esterification cross-linking reaction and the hot dissolution dyeing of disperse dyes are triggered simultaneously.

[0021] S5. Post-treatment: After baking, the fabric is washed in a continuous washing machine in sequence with 40℃ warm water once, 75℃ hot soap wash with 2g / L soap detergent twice (5 minutes per wash), and cold water twice. Finally, it is dried and shaped.

[0022] Example 2: A short-process dyeing process for wrinkle-resistant polyester-cotton, comprising the following steps: S1. Preparation of thermally induced phase change catalytic microcapsules: The operation is the same as in Example 1, except that high-density modified polyethylene wax with a melting temperature of 140℃ is used as the wall material, the mass ratio of core material to wall material is 1:2, and the emulsification speed is 6000 r / min.

[0023] S2. Prepare the dormant working solution in the same bath: 1 g / L disperse dye, 2 g / L reactive dye containing phosphonic acid groups, 30 g / L polycarboxylic acid crosslinking agent (butanetetracarboxylic acid to citric acid mass ratio 1:2), and 15 g / L thermally induced phase change catalytic microcapsules. Adjust the pH to 6.0.

[0024] S3, Rolling and Medium-Temperature Penetration: Rolling allowance controlled at 65%, pre-drying temperature 100℃, moisture content reduced to 15%.

[0025] S4. High-temperature in-situ release and cross-linking: Baking temperature 170℃, baking time 120 seconds.

[0026] S5. Post-processing: Same as in Example 1.

[0027] Example 3: A short-process dyeing process for wrinkle-resistant polyester-cotton, comprising the following steps: S1. Preparation of thermally induced phase change catalytic microcapsules: The operation is the same as in Example 1, except that the mass ratio of core material to wall material is 1:4 and the emulsification speed is 8000 r / min.

[0028] S2. Prepare the dormant working solution in the same bath: 5 g / L disperse dye, 8 g / L reactive dye containing phosphonic acid groups, 60 g / L polycarboxylic acid crosslinking agent (butanetetracarboxylic acid to citric acid mass ratio 1:1.5), and 30 g / L thermally induced phase change catalytic microcapsules. Adjust the pH to 6.5.

[0029] S3, Rolling and Medium-Temperature Penetration: Rolling allowance controlled at 75%, pre-drying temperature 120℃, moisture content reduced to 20%.

[0030] S4. High-temperature in-situ release and cross-linking: Baking temperature 190℃, baking time 90 seconds.

[0031] S5. Post-processing: Same as in Example 1.

[0032] Comparative Example 1: Traditional two-bath process.

[0033] The traditional long-process technology of first dispersive dyeing, then reactive dyeing, and finally anti-wrinkle finishing is adopted. First, the polyester-cotton fabric is disperse dyed at 130℃ and pH=4.5, followed by reduction washing; then, reactive dyes are added at pH=10.5 for dyeing and alkali fixation, followed by water washing and soaping; finally, a finishing solution (pH=3.5) containing 45g / L of polycarboxylic acid crosslinking agent and 10g / L of sodium hypophosphite (uncoated) is prepared separately, and after two dips and two nips, it is baked at 180℃ for 100 seconds.

[0034] Comparative Example 2: Direct co-bath method, free catalyst, no microencapsulation.

[0035] The formulation and operation are the same as in Example 1, except that the microcapsule preparation step in S1 is skipped. Instead, 5 g / L of unencapsulated free sodium hypophosphite is directly added to the working solution in S2. The pH of the working solution is adjusted to 4.5 as in traditional co-bath to ensure the activity of the crosslinking agent. The subsequent padding, pre-drying, and baking conditions are exactly the same.

[0036] Comparative Example 3: Microencapsulation process for low-melting-point wall materials.

[0037] The formulation and operation are the same as in Example 1, except that the wall material in step S1 is replaced with conventional polyethylene glycol (PEG4000) with a melting temperature of 60°C.

[0038] Performance testing and results analysis: The fabrics obtained in the above embodiments and comparative examples were subjected to performance tests.

[0039] Staining depth (K / S value): Measured using a Datacolor colorimeter at the maximum absorption wavelength. The larger the K / S value, the deeper the apparent staining depth.

[0040] Tensile strength retention rate (%): The warp tensile strength was determined according to GB / T3923.1-2013. Retention rate = (strength after finishing / original fabric strength) × 100%.

[0041] Folded recovery angle (WRA, longitude + latitude): Measured according to GB / T3819-1997.

[0042] Color fastness to washing: Tested according to GB / T3921-2008 standard, and the fading grade is rated (1-5, with 5 being the best).

[0043] Test data results table: Original fabric 0.05 100 145 - Example 1 14.62 82.3 248 4-5 Example 2 7.85 84.1 235 4-5 Example 3 18.91 80.5 255 4-5 Comparative Example 1 14.85 70.2 251 4 Comparative Example 2 9.34 61.5 240 3 Comparative Example 3 10.12 64.8 242 3-4 As shown in the table above, the short-process of the present invention achieves a level comparable to the traditional long two-bath process in terms of K / S value and fold recovery angle, but significantly improves the breaking strength retention rate (82.3% vs 70.2%), proving that asynchronous catalysis protects cotton fibers from severe acid-induced degradation.

[0044] Comparative Example 2, which used a free catalyst, not only experienced a significant decrease in strength (61.5%), but also a substantial reduction in the K / S value to 9.34, with a color fastness rating of only 3. This indicates that the catalyst's premature initiation led to the formation of a cross-linked network during the penetration stage, resulting in severe steric hindrance that blocked dye uptake. This demonstrates the necessity of introducing thermally induced phase change microcapsules.

[0045] Comparative Example 3 used a wall material with a melting point of 60℃. During the pre-baking stage at 110℃, the microcapsules ruptured and failed, transforming into a free catalytic state. The test data showed a sharp drop, and its effect was close to that of Comparative Example 2. This proves that defining the melting temperature of the wall material at the threshold of 140℃-150℃ is the key physical boundary condition for achieving precise asynchronous reaction and spatiotemporal isolation.

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

Claims

1. A wrinkle-resistant polyester-cotton short-process dyeing process, characterized in that, Includes the following steps: S1. Preparation of thermally induced phase change catalytic microcapsules: Sodium hypophosphite catalyst is ground and pulverized; Polyamide hot-melt resin or high-density modified polyethylene wax with a melting temperature between 140℃ and 150℃ was selected as the wall material and heated to complete melting. The pulverized catalyst was added as the core material to the molten wall material, and a nonionic surfactant was added to control the mass ratio of the core material to the wall material to be 1:2-1:

4. The mixture was melt-dispersed under high-speed shear conditions of 6000-8000 r / min for 15-20 minutes, followed by spray condensation granulation, filtration and drying to obtain thermally induced phase change catalytic microcapsules with a particle size distribution of 1-3 μm. S2. Preparation of dormant co-bath working solution: Disperse dye, reactive dye, polycarboxylic acid crosslinking agent and the thermo-induced phase change catalytic microcapsules prepared in S1 are added to deionized water and mixed evenly. The pH value is adjusted to 6.0-6.5 using glacial acetic acid and sodium acetate buffer to obtain the dormant co-bath working solution. S3. Padding and Medium-Temperature Penetration: The pretreated polyester-cotton fabric is immersed in a dormant working solution for two dips and two pads, with the padding rate controlled at 65%-75%. The fabric is then placed in an infrared pre-drying device at 100℃-120℃ for pre-drying until the fabric moisture content is 15%-20%. S4. High-temperature in-situ release and cross-linking: The pre-dried fabric is sent into a hot air baking equipment and baked at 170℃-190℃ for 90-120 seconds. Under this temperature condition, the wall material of the thermo-induced phase change catalytic microcapsules attached to the fiber gaps and amorphous regions undergoes thermo-melting, releasing the core catalyst in situ, and simultaneously triggering the dehydration esterification cross-linking reaction of the polycarboxylic acid cross-linking agent with the cotton fiber, as well as the thermo-melting dyeing of the polyester fiber by the disperse dye. S5. Post-treatment: After baking, the fabric is washed in 40℃ warm water, then in 70-80℃ hot soaping with soaping agent to remove floating color and unreacted substances, and finally washed with cold water and dried.

2. The wrinkle-resistant polyester-cotton short-process dyeing process according to claim 1, characterized in that, In step S1, the grinding and pulverizing process involves grinding and pulverizing the catalyst until the D50 particle size is less than 0.5 μm.

3. The wrinkle-resistant polyester-cotton short-process dyeing process according to claim 1, characterized in that, In S1, the nonionic surfactant is fatty alcohol polyoxyethylene ether.

4. The wrinkle-resistant polyester-cotton short-process dyeing process according to claim 1, characterized in that, In S2, the reactive dye is a reactive dye containing phosphonic acid groups; the polycarboxylic acid crosslinking agent is a mixture of butanetetracarboxylic acid and citric acid in a mass ratio of 1:1 to 1:

2.

5. The wrinkle-resistant polyester-cotton short-process dyeing process according to claim 1, characterized in that, The mass concentrations of the main components in the dormant co-bath working solution are as follows: disperse dye 1-5 g / L, reactive dye 2-8 g / L, polycarboxylic acid crosslinking agent 30-60 g / L, and thermo-induced phase change catalytic microcapsules 15-30 g / L.

6. The wrinkle-resistant polyester-cotton short-process dyeing process according to claim 5, characterized in that, The dormant working solution also contains 1-2 g / L of electrolyte-resistant isomeric tridecyl alcohol polyoxyethylene ether penetrant and 10-20 g / L of polyacrylic acid anti-migration agent.

7. The wrinkle-resistant polyester-cotton short-process dyeing process according to claim 1, characterized in that, In S3, the polyester-cotton fabric is a polyester-cotton blended fabric with a polyester / cotton mass ratio of 65 / 35.

8. The wrinkle-resistant polyester-cotton short-process dyeing process according to claim 1, characterized in that, In step S5, the specific operation of hot soap washing is as follows: the fabric is placed in a solution containing 2-3 g / L of soaping agent and soaped at a temperature of 70℃-80℃.

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