Dyeing method of polyester material

Abstract

The invention provides a dyeing method of a polyester material, and belongs to the field of dyeing. The volume fraction of ethyl alcohol in an ethyl alcohol-water solvent system is controlled to be 15%-35%, disperse dye is dispersed, the dye is partially dissolved after high-pressure reaction, the dye particle size and the system stability reach the balance suitable for medium and low temperature dyeing, dye particles can just enter fiber molecule gaps at the suitable temperature, and the dyeing effect is good. Dyeing can be carried out in the temperature range of 95-115 DEG C, and the reaction temperature is far lower than the reaction temperature of 120-130 DEG C in a traditional high-temperature and high-pressure method. According to the method, medium-low-temperature high-pressure dyeing of the polyester fibers is realized by using an ethanol-water system, the linear dependency relationship between the concentration of an alcohol assistant and the dyeing temperature is broken through, and under the synergistic effect of the ethanol volume concentration of 15-35% (preferably 25%) and the temperature of 95-115 DEG C, the dyeing temperature is reduced by 15-35 DEG C (compared with the traditional dyeing temperature of 120-130 DEG C), and the K / S value is increased by 30-50% compared with that of a pure water system with the same temperature.

Description

Technical Field

[0001] The invention relates to the technical field of dyeing, in particular to a dyeing method for polyester materials. Background Art

[0002] Polyester fibers have a compact structure and high crystallinity, but lack reactive groups in their molecular structure that can bind to water-soluble dyes. Therefore, they can typically only be dyed with disperse dyes. Only at temperatures above the glass transition temperature (Tg) can the fiber's molecular chains move more rapidly, increasing the inter-molecular pores and allowing dye molecules to penetrate the fiber. Because disperse dye dyeing methods, such as high-temperature, high-pressure, or hot-melt methods, require high equipment requirements and consume significant energy, research on environmentally friendly disperse dye dyeing methods for polyester fiber (polyester) textiles has been growing in recent years.

[0003] Patent publication number CN116334935A discloses a polyester dyeing method that saves energy and reduces emissions. This method involves placing fabric in a dye vat and adding water. After pre-treatment at 85-100°C, disperse dyes and dispersants are added and dyeing is carried out at 125-135°C for 30-50 minutes under high temperature and high pressure. Compared to traditional dyeing processes, this method significantly shortens the dyeing process and significantly reduces water and hydrosulfite usage, saving costs. It offers the advantages of energy conservation and emission reduction, efficient production, and good reduction cleaning effects. However, this method still uses the traditional dyeing process with disperse dyes at temperatures above 120°C, and pre-treats the fabric with alkali and penetrants, failing to overcome the limitations of traditional dyeing processes.

[0004] Patent publication number CN103243588A discloses a method for dyeing polyester textiles under high temperature and high pressure. This method utilizes a high ratio of alcoholic organic solvents and a small amount of water at high temperature and high pressure to dye polyester. This method addresses the difficulties and poor levelness of dyeing traditional textiles under high temperature and high pressure. However, this technology still requires high temperatures for polyester dyeing, resulting in high energy consumption, large amounts of alcoholic organic solvents, and high costs.

[0005] In view of this, it is necessary to propose a new polyester textile dyeing method to solve the above problems. Summary of the Invention

[0006] In view of the technical problems existing in the background technology, the present application provides a dyeing method for polyester materials. This method disperses the disperse dye by controlling the volume fraction of ethanol to 15%-35%, and partially dissolves the dye after high-pressure reaction, so that the dye particle size reaches an appropriate size. The dye particles can just enter the gaps between fiber molecules at an appropriate temperature, thereby achieving dyeing within a temperature range of 95-115°C, which is much lower than the traditional high temperature and high pressure method.

[0007] The embodiment of the present application provides a dyeing method of polyester material, comprising the following steps: S1, configuring a dyeing solution: adding a disperse dye into a dyeing cup containing an ethanol and water mixed solution to obtain a dyeing solution; wherein the volume fraction of ethanol in the ethanol and water mixed solution is 15%-35%; S2, dyeing: placing polyester textile material into the dyeing solution prepared in step S1 to perform dyeing; wherein an infrared dyeing machine is used for dyeing; S3, after dyeing, performing soaping, washing and drying to obtain a dyeing finished product.

[0008] Further, in step S2, the dyeing process is as follows: increasing the temperature to 95-115 DEG C at a speed of 1-9 DEG C / min and keeping the temperature for 30-60 min.

[0009] Further, the concentration of the disperse dye is 2-8% o.w.f.

[0010] Further, the dyeing solution bath ratio is 1: (20-50).

[0011] Further, step S3 comprises the following process: adding 5 g / L of soap powder and 2 g / L of sodium carbonate into a soaping steel cup, increasing the temperature to 60 DEG C, soaping for 30 min, taking out the fabric in the soaping steel cup to perform washing, washing the residual soaping solution and alkali solution on the surface of the polyester and drying.

[0012] Further, the polyester textile material is one of polyester fiber, polyester fabric and polyester filament.

[0013] The polyester material dyeing method has the following beneficial effects: (1) The polyester material dyeing method uses a quantitative proportion of ethanol / water solvent as a solvent to disperse the disperse dye, and after high-pressure reaction, the dye is partially dissolved, the dye particle size and system stability reach a balance suitable for low-temperature dyeing, the dye particles can just enter the intermolecular gap of the fiber at a suitable temperature, and the dyeing is performed at a temperature range of 95-115 DEG C, which is much lower than the traditional high-temperature and high-pressure method, and the industrial dyeing effect can be achieved. The method uses part of ethanol to replace water, reduces water resource waste and environmental pollution, breaks the linear dependence relationship between the concentration of alcohol additives and the dyeing temperature, realizes the reduction of 15-35 DEG C of the dyeing temperature (compared with the traditional 120-130 DEG C) under the synergistic action of the ethanol volume concentration of 15%-35% (preferably 25%) and the temperature of 95-115 DEG C, and the K / S value of the pure water system at the same temperature is improved by 30-50%. When the ethanol concentration is 25%, the dyeing solution is most stable (the Zeta potential is the highest and the particle size is the smallest), and the PET dyeing effect is significantly improved. Too high concentration (such as 100%) will destroy the stability and reduce the dyeing quality.

[0014] (2) The color depth of polyester fibers after medium-low temperature dyeing of the present invention is comparable to that of traditional industrial dyeing, and the color fastness is good. It is superior to traditional dyeing processes in terms of time and energy consumption costs.

[0015] (3) The present invention uses a medium-low temperature and high pressure dyeing method of an ethanol-water system to dye polyester fibers, which not only reduces the dyeing temperature, but also does not require the addition of dispersants and insurance powder during the dyeing process, thereby saving water and insurance powder, saving costs, and greatly reducing the safety risk of insurance powder storage.

[0016] (4) The ethanol added in the dyeing process of the present invention can be recovered and recycled by evaporating the organic solvent.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0019] Figure 1 This is a dyeing process curve diagram of the dyeing method for the polyester material of the present invention.

[0020] Figure 2 The particle sizes of dye particles with different alcohol contents before and after the reaction at 105°C in Examples 1, 3-4 and Comparative Examples 1-3 are shown.

[0021] Figure 3 The surface zeta potential of dye particles with different alcohol contents before and after the reaction at 105° C. in Examples 1, 3-4, and Comparative Examples 1-3 is shown.

[0022] Figure 4 The absorbance of the dye solutions before and after the dye reaction in Examples 1, 3-4, and Comparative Examples 1 and 3 (no fiber added); wherein (a) represents an ethanol content of 0%, (b) represents an ethanol content of 15%, (c) represents an ethanol content of 25%, (d) represents an ethanol content of 35%, and (e) represents an ethanol content of 100%.

[0023] Figure 5 The dyeing effects of different proportions of ethanol dye solution at 105°C in Examples 1-4 and Comparative Examples 1-3 are shown.

[0024] Figure 6The figures are the K / S results of the dyeing processes of Example 1 and Comparative Example 4.

[0025] Figure 7 The figures are the K / S results of the dyeing processes of Example 5 and Comparative Example 5.

[0026] Figure 8 The K / S results of the dyeing process of Example 6 and Comparative Example 6 are shown. DETAILED DESCRIPTION

[0027] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0029] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0030] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0032] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0033] For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0034] Traditional polyester fiber dyeing with disperse dyes usually adopts high temperature and high pressure methods above 120°C to increase the movement between fiber molecular chains, expand the intermolecular movement gap, and help dye molecules enter the interior of the fiber, or use highly toxic aromatic carriers for dyeing. Traditional processes have high energy consumption, long processes and large wastewater discharge.

[0035] The present application provides a method for dyeing a polyester material, comprising the following steps: S1, preparing a dye solution: adding a disperse dye to a dye cup containing a mixed solution of ethanol and water to obtain a dye solution; wherein the volume fraction of ethanol in the mixed solution of ethanol and water is 15%-35%; S2, dyeing: placing the polyester textile material into the dye solution prepared in step S1 for dyeing; wherein the dyeing is performed using an infrared dyeing machine; Among them, the concentration of disperse dye is 2~8%owf.

[0036] The dye bath ratio is 1:(20-50).

[0037] The dyeing process is as follows: heating to 95-115°C at a rate of 1-9°C / min, keeping warm for 30-60 min, and taking out after cooling.

[0038] Polyester textile material is one of polyester fiber, polyester fabric and polyester filament.

[0039] S3, after dyeing is completed, soaping, washing with water and drying are performed to obtain the dyed product.

[0040] Specifically, step S3 includes the following process: adding 5g / L soap powder and 2g / L sodium carbonate into the soap washing steel cup, with a bath ratio of 1:50, heating to 60°C, soaping for 30 minutes, taking out the fabric from the soap washing steel cup and washing it with water to clean the residual soap solution and alkali solution on the surface of the polyester and drying it.

[0041] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are all commercially available conventional products.

[0042] Example 1 See also Figure 1 As shown, this embodiment provides a method for dyeing a polyester material, comprising the following steps: S1, preparing dye solution: adding disperse dye to a dye cup containing a mixed solution (solvent) of ethanol and water to obtain dye solution; wherein the volume ratio of ethanol to water is 25 ml:75 ml, that is, the volume fraction of ethanol in the mixed solution of ethanol and water is 25%; the concentration of disperse dye is 2% owf; S2, dyeing: placing the polyester fiber into the dye solution prepared in step S1 for dyeing; wherein, the dyeing is performed using an infrared dyeing machine; specifically, the bath ratio is 1:50; during dyeing, the temperature is raised to 105°C at a rate of 2°C / min and kept at this temperature for 60 min, then cooled to 50°C, and then the liquid is drained.

[0043] S3. After dyeing is completed, add 5 g / L soap powder and 2 g / L sodium carbonate into the soaping steel cup with a bath ratio of 1:50, heat to 60°C, and soap for 30 minutes. Take out the polyester fiber from the soaping steel cup and wash it with water to clean the residual soap solution and alkali solution on the surface of the polyester and dry it to obtain the finished dyed product.

[0044] Examples 2-4 and Comparative Examples 1-3 Examples 2-4 and Comparative Examples 1-3 provide a method for dyeing a polyester material. Compared to Example 1, the difference lies in varying the volume fraction of ethanol in the ethanol-water mixture, as shown in the table below. The remaining steps are generally the same as in Example 1 and are not further described here.

[0045] Figure 2 The particle sizes of dye particles with different alcohol contents before and after reaction at 105°C in Examples 1, 3-4 and Comparative Examples 1-3 are shown.

[0046] Figure 3 The surface zeta potential of dye particles with different alcohol contents before and after reaction at 105° C. in Examples 1, 3-4, and Comparative Examples 1-3 is shown.

[0047] Figure 4 The absorbance of dye solutions with different ethanol ratios (Examples 1, 3-4 and Comparative Examples 1 and 3) before and after reaction (no fiber added).

[0048] Figure 5 The dyeing effects of Examples 1, 3-4 and Comparative Examples 1-3 are compared.

[0049] from Figure 2 and Figure 3 It can be seen that compared with water as a solvent for disperse dyes, ethanol can promote the dissolution of disperse dyes and help them remain stable in the dye solution.

[0050] Specifically, in Figure 2 and Figure 3In the experiment, when the ethanol concentration in the water-alcohol mixture increases from 0 to 15%, the Zeta potential of the disperse dye increases and the particle size of the dye particles decreases (the particle size after the reaction is 200-400 nm and the Zeta potential is 85-250 mV). When the ethanol concentration reaches 25%, the Zeta potential reaches a maximum value and the particle size reaches a minimum value. This is the optimal dispersion state of the disperse dye and is also the optimal ethanol concentration for dyeing polyester fibers (PET). As the ethanol concentration continues to increase (ethanol concentration is greater than 35%), the Zeta potential of the disperse dye begins to decrease, the dispersion system becomes unstable, and the dyeing effect deteriorates ( Figure 5 The larger the absolute value of the Zeta potential of the dye solution in 25% ethanol, the better the colloid dispersion stability of the dye solution itself, the less likely the dye particles are to aggregate and precipitate, and more of them can enter the fiber.

[0051] Under high pressure conditions at around 100°C, ethanol in a water-alcohol mixture vaporizes more easily than pure water. The increase in gas leads to a rise in pressure in the closed environment. This intensifies the molecular chain motion of polyester fibers (PET), and disperse dyes also gain higher energy under the corresponding temperature and high pressure conditions, which is beneficial to the entire dyeing process. Figure 4 (a) in the figure shows that, with 0% ethanol (i.e. pure water), although the dye in pure water is hydrophobic, the dispersant contained in the industrial dye forms relatively stable micelles after being wrapped, and the absorbance before and after the reaction remains basically unchanged. When 15%, 25% and 35% ethanol solutions are used as solvents, the absorbance value of the dyeing solution decreases after the reaction treatment of the dyeing procedure. The chromophores of the dye molecules inside the aggregates are "shielded", and their electronic transitions are suppressed or coupled, resulting in a decrease in their effective absorbance at the characteristic absorption wavelength; on the contrary, when 100% ethanol solution is used as the solvent, the 100% ethanol environment promotes the dissolution of more disperse dyes, more molecular chromophore functional groups are detected, and the absorbance value of the dyeing solution increases. Combination Figure 2 The particle size distribution law of Figure 4 More surface functional groups will be revealed in medium-pure ethanol, but the aggregation phenomenon is also obvious, which is not conducive to the dyeing process of disperse dyes on polyester fibers, resulting in poor dyeing effect of polyester fibers.

[0052] Figure 4 The initial absorbance in the characteristic 400-600nm band for the low- to medium-ethanol groups (15%, 25%, and 35% ethanol concentrations) was much higher (0.8) than for the pure ethanol group (0.2), indicating that the dye initially dispersed better in aqueous ethanol solutions (possibly because the dispersant was more effective in mixed solvents). The dye initially aggregated significantly in pure ethanol (absorbance of only 0.2), but high temperatures disrupted the initial aggregation, releasing monomers and revealing more chromophores.

[0053] On the other hand, in a water / ethanol mixture, the absorption of the solvent lowers the glass transition temperature of polyester fibers, increasing the diffusion coefficient of disperse dyes into the fibers. Furthermore, the addition of ethanol enhances the affinity between the dye and the polyester fiber and reduces surface energy, acting as a surfactant. In summary, ethanol increases pressure, improves the stability of the dispersion system, and enhances the affinity between the fiber and the dye during the dyeing process. These three effects significantly improve the dyeing performance of polyester fibers.

[0054] Comparative Example 4 Compared with Example 1, Comparative Example 4 is different in that the solvent used is pure water and the dyeing temperature is 125°C.

[0055] Figure 6 The figures are the K / S results of the dyeing processes of Example 1 and Comparative Example 4.

[0056] The results showed that the dyeing effect of 125°C pure water was equivalent to that of Example 1 (105°C, 25% ethanol), that is, Example 1 reached the industrial-grade dyeing level, achieved a 20°C reduction in dyeing temperature, and saved energy consumption.

[0057] Example 5 Compared with Example 2, Example 5 is different in that the dyeing temperature is 95°C.

[0058] Comparative Example 5 Compared with Example 5, the difference of Comparative Example 5 is that the solvent used is pure ethanol, that is, a pure ethanol solvent system, and the dyeing temperature is 95°C.

[0059] Figure 7 The figures are the K / S results of the dyeing processes of Example 5 and Comparative Example 5.

[0060] The results showed that the color depth K / S value of polyester fiber dyed with pure ethanol at 95°C could only reach 3, while when the ethanol content was 30%, the K / S value could reach 10. This reflects that trace ethanol, as an auxiliary agent in the disperse dye system, has the effect of enhancing the dyeing effect.

[0061] Example 6 Example 6 provides a method for dyeing a polyester material. Compared to Example 1, the difference is that the disperse dye concentration is increased from 2% to 5%. The rest is substantially the same as Example 1 and will not be repeated here.

[0062] Comparative Example 6 Compared with Example 6, Comparative Example 6 is different in that the solvent used is pure water, that is, a pure water solvent system, and the dyeing temperature is 105°C.

[0063] Figure 8Results of dyeing process K / S for Example 6 and Comparative Example 6.

[0064] The results show that the dyeing system with 25% ethanol achieves nearly 50% improvement in color depth, compared with the dyeing result of K / S 9.8 of pure water dispersion dye at the same temperature, and the dyeing of 25% ethanol is nearly 20. The reason may be that 25% ethanol dissolves part of the dye and successfully enters the swollen fiber gap with water molecules wrapped around the dispersed dye. When the temperature rises, water / pure mixture produces steam, the pressure in the system rises, forcing the fiber to open the molecular pores, and the dye successfully enters the interior of the fiber.

[0065] Experiments show that when the concentration of dispersion dye is less than 2% o.w.f, the ethanol / water system cannot promote more dispersion dye particles to enter the interior of the fiber due to low dye concentration, and industrial dyeing effect cannot be achieved. When the concentration of dispersion dye is higher than 8% o.w.f, which is far higher than the concentration required in actual experiments or industrial production, it has no practical significance, so the concentration range of dispersion dye is 2-8% o.w.f.

[0066] It should be noted that the polyester textile material is one of polyester fiber, polyester fabric and polyester filament.

[0067] In summary, the polyester fiber is dyed in the ethanol-water system at a temperature of 95-115°C in the present application. The dispersion dye is first dissolved in the ethanol / water system in a quantitative ratio to make the dye particle size and system stability reach a balance suitable for dyeing at medium and low temperatures. Compared with the water system dyeing under the same conditions, the color fastness is high, which meets the customer's requirements. The trace amount of ethanol for dyeing at medium and low temperatures and high concentrations achieves the same effect as traditional water-based dyeing. Compared with the existing high temperature and high pressure dyeing method, not only the dyeing temperature is reduced, but also the use of dispersing agent and safety powder is reduced, and part of the water is replaced by ethanol to achieve the purpose of water saving.

[0068] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role and effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications of the embodiments that can be thought of by those skilled in the art, and other ways constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for dyeing a polyester material, characterized in that: The following steps are involved: S1, preparing a dye solution: adding a disperse dye to a dye cup containing a mixed solution of ethanol and water to obtain a dye solution; wherein the volume fraction of ethanol in the mixed solution of ethanol and water is 15%-35%; S2, dyeing: placing the polyester textile material into the dye solution prepared in step S1 for dyeing; wherein the dyeing is performed using an infrared dyeing machine; S3, after dyeing is completed, soaping, washing with water and drying are performed to obtain the dyed product.

2. The method for dyeing a polyester material according to claim 1, characterized in that: In step S2, the dyeing process is as follows: heating to 95-115°C at a rate of 1-9°C / min and keeping the temperature for 30-60 min.

3. The method for dyeing a polyester material according to claim 1, characterized in that: The concentration of the disperse dye is 2-8% owf.

4. The method for dyeing a polyester material according to claim 1, characterized in that: The dye bath ratio is 1:(20-50).

5. The method for dyeing a polyester material according to claim 1, characterized in that: Step S3 includes the following process: adding 5 g / L soap powder and 2 g / L sodium carbonate into the soap washing steel cup, with a bath ratio of 1:50, heating to 60°C, soaping for 30 minutes, taking out the fabric from the soap washing steel cup and washing it with water to clean the residual soap solution and alkali solution on the surface of the polyester and drying it.

6. The method for dyeing a polyester material according to claim 1, characterized in that: The polyester textile material is one of polyester fiber, polyester fabric and polyester filament.

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