A method for double-face differential environment-friendly dyeing of cotton fabric

Abstract

The application discloses a method for double-side differential environment-friendly dyeing of cotton fabric and belongs to the field of double-side differential environment-friendly dyeing. Hydrophilic monomers are grafted to one side of the fabric by using ultraviolet light grafting technology, and the purpose of double-side differential environment-friendly dyeing of cotton fabric by natural safflower dye at room temperature without adding salt is achieved, so that the cotton fabric after dyeing can keep the performance and has the differential dyeing effect of different color depths on two sides, and the purpose of "one object with multiple uses" is achieved, so that the use field of the fabric is expanded and the use of the fabric is increased.

Description

Technical Field

[0001] This invention belongs to the field of double-sided differentiated green and environmentally friendly dyeing, and specifically relates to a method for double-sided differentiated environmentally friendly dyeing of cotton fabrics. Background Technology

[0002] Double-sided differential dyeing fabrics not only achieve different colors on both sides but also endow the fabric with unique properties that differ in wearing characteristics on each side, making them a promising type of fabric for development. Most double-sided differential dyeing fabrics are blended fabrics, utilizing the differences in dyeing properties between different types of fibers. However, it is difficult to achieve double-sided differential dyeing for pure textiles.

[0003] Ultraviolet (UV) radiation has relatively low energy, allowing the grafting reaction to be controlled to occur only on one side, making it suitable for preparing materials with different properties on both sides. Furthermore, UV radiation has less penetrating power than high-energy radiation. At room temperature, various functional monomers are rapidly grafted onto the polymer surface. Graft polymerization can be strictly confined to the surface or subsurface of the material, without causing significant polymer degradation. In addition, UV radiation sources and equipment are inexpensive and easy to operate continuously. Double-sided differentiated dyeing utilizes UV grafting technology to graft hydrophilic monomers onto one side of cotton fabric, enabling natural safflower dyes to dye one side of the fabric at room temperature. This achieves differentiated dyeing effects with different shades on both sides, achieving the goal of "one material for two uses" or "one material for multiple uses," expanding the application areas of textiles and increasing their value. Summary of the Invention

[0004] To address the challenge of achieving differentiated dyeing on both sides of pure textiles, this invention provides a novel environmentally friendly method for differentiated dyeing of cotton fabrics on both sides. Utilizing ultraviolet light grafting technology, hydrophilic monomers are grafted onto one side of the cotton fabric, enabling differentiated and environmentally friendly dyeing of the fabric on both sides at room temperature without the addition of salt. This allows the dyed fabric to retain its inherent properties while exhibiting different colors on both sides, presenting distinct effects and achieving a "multi-purpose" effect. This expands the application areas of cotton fabrics and increases their value.

[0005] This invention provides a method for differentiated and environmentally friendly double-sided dyeing of cotton fabrics, the specific operation steps of which are as follows:

[0006] (1) Dissolve the hydrophilic monomer and the photoinitiator in a solvent at a certain concentration to obtain a homogeneous solution;

[0007] (2) After soaking the cotton fabric in the solution obtained in step (1), place the cotton fabric on the pressure roller for squeezing;

[0008] (3) The cotton fabric squeezed in step (2) is subjected to single-sided irradiation under an ultraviolet irradiation instrument, wherein the irradiation energy of the ultraviolet lamp is 2.5~20J / cm. 2 .

[0009] (4) After soaking the cotton fabric obtained in step (3) in the natural safflower dye extract for dyeing, the cotton fabric with double-sided differential dyeing is obtained.

[0010] Furthermore, in the above technical solution, the solvent in step (1) is ethanol; the photosensitizer is benzophenone, and the mass concentration of the photosensitizer is 2-10%; the hydrophilic monomer is N-(3-dimethylaminopropyl)methacrylamide, and the mass concentration of the hydrophilic monomer is 2-22%.

[0011] Furthermore, in the above technical solution, the cotton fabric is a dried cotton fabric, and the drying conditions are: temperature of 40-50℃ and time of 20-30min.

[0012] Furthermore, in the above technical solution, the mass ratio of the solution to the cotton fabric is 50:1 to 70:1, the soaking time in step (2) is 3 to 5 minutes, and the squeezing rate is 50 to 60%.

[0013] Furthermore, in the above technical solution, the ultraviolet irradiation energy in step (3) is 2.5, 5, 7.5, 10, 12.5, 15, 17.5, or 20 J / cm². 2 One of them.

[0014] Furthermore, in the above technical solution, the safflower natural dye extract in step (4) is obtained by ultrasonic extraction from safflower. The specific preparation method is as follows: safflower is washed and dried, solvent is added, and ultrasonic treatment is performed to obtain safflower natural dye extract; wherein, the extraction solvent used is deionized water, the ratio of safflower to solvent is 1:15 to 1:25, preferably 1:20; the working frequency of the ultrasonic treatment is 30 to 40 kHz, preferably 35 kHz, the temperature is room temperature, and the extraction time is 100 to 120 min.

[0015] Furthermore, in the above technical solution, the staining bath ratio in step (5) is 1:30 to 1:80.

[0016] Furthermore, in the above technical solution, the staining bath ratio in step (5) is one of 1:30, 1:40, 1:50, 1:60, 1:70, or 1:80.

[0017] Furthermore, in the above technical solution, the soaking time of the natural safflower dye extract in step (5) is 30-35 minutes.

[0018] The present invention also provides a cotton fabric with double-sided differential dyeing obtained by the above-mentioned double-sided differential dyeing method, especially its application in differential dyeing of pure textile fabrics.

[0019] This invention grafts hydrophilic monomers onto one side of cotton fabric and utilizes the characteristic that ultraviolet light has relatively low energy, allowing the grafting reaction to be controlled to occur only on one side, so that the dyed cotton fabric can achieve different shades of color on both sides.

[0020] The ultraviolet (UV) photografting process of this invention involves immersing dried cotton fabric in a solution containing anhydrous ethanol, N-(3-dimethylaminopropyl)methacrylamide, and benzophenone. The fabric is then pressed onto rollers at a 60% padding rate. The padded cotton fabric is then irradiated with UV light on one side only, with the UV irradiation energy adjusted by the conveyor belt speed and number of rotations. Subsequently, the cotton fabric is immersed in a natural safflower dye extract for 30 minutes, followed by soaping and washing. Finally, the double-sided differentiated dyed cotton fabric is dried.

[0021] The cotton fabric dyed by this invention can achieve different shades of color on both sides, and the dye is fixed only on one side of the cotton fabric, which can effectively prevent the dye on one side from penetrating to the other side. This ensures that the natural safflower dye has a high color yield and also reduces the dyeing temperature of the natural safflower dye.

[0022] This invention investigates the effects of factors such as ultraviolet irradiation energy, monomer concentration, photosensitizer concentration, and dyeing bath ratio on the depth of double-sided dyeing, thereby determining the optimal process for differentiated and environmentally friendly double-sided dyeing of cotton fabrics.

[0023] Further discussion of the following optimal conditions:

[0024] (1) Change the concentration of the photosensitizer

[0025] Using benzophenone (BP) as a photosensitizer, under ultraviolet irradiation, the free radicals generated by the photosensitizer molecules adsorb hydrogen from cotton fiber molecules, producing free radicals on the surface of the cotton fabric, thereby initiating the grafting of monomer molecules onto the fabric. The optimal concentration of the photosensitizer is 2%.

[0026] (2) Change monomer concentration

[0027] N-(3-dimethylaminopropyl)methacrylamide (DMAPMA) was used as the grafting monomer. Natural safflower dye formed hydrogen bonds with the second amino group in DMAPMA grafted onto cotton fabric. The optimal monomer concentration was 16%.

[0028] (3) Change the energy of ultraviolet radiation

[0029] As the ultraviolet energy increases, the grafting reaction gradually becomes more effective, leading to a gradual increase in the grafting rate and dyeing depth of the fabric. This effect is further enhanced when the ultraviolet energy reaches 12.5 J / cm². 2 The effect is best achieved at that time.

[0030] (4) Change the dyeing bath ratio

[0031] Increasing the dyeing liquor ratio can improve the evenness of dyeing in cotton fabrics; the optimal dyeing liquor ratio is 1:60.

[0032] Beneficial effects of this invention:

[0033] Double-sided differential dyeing of fabrics not only achieves different colors on each side but also endows the fabric with unique properties that differ in wearability on each side. Most double-sided differential dyeing fabrics are blended fabrics, utilizing the differences in dyeing properties between different types of fibers. However, it is difficult to achieve double-sided differential dyeing for pure textiles. This invention proposes a novel environmentally friendly double-sided differential dyeing method for pure cotton fabrics. The core of this method involves grafting hydrophilic monomers onto one side of the cotton fabric. Taking advantage of the relatively low energy of ultraviolet light, the grafting reaction can be controlled to occur only on one side, allowing the dyed cotton fabric to achieve different shades on each side. Furthermore, the dyeing is carried out at room temperature without the addition of salt, thus reducing negative environmental impacts and making it highly beneficial for environmental protection. Attached Figure Description

[0034] Figure 1 The double-sided differentiated dyed cotton fabric prepared in Example 1.

[0035] Figure 2 The double-sided differentiated dyed cotton fabric prepared for Comparative Example 1.

[0036] Figure 3 The double-sided differentiated dyed cotton fabric prepared in Example 2.

[0037] Figure 4 The double-sided differentiated dyed cotton fabric prepared in Example 3. Detailed Implementation

[0038] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0039] The present invention will be further described in conjunction with the following embodiments.

[0040] The main equipment used: SK-102-150 ultraviolet irradiation instrument (Shenzhen Sankun Technology Co., Ltd.).

[0041] The preparation method of safflower natural dye extract in the following examples and comparative examples is as follows: safflower is washed and dried, deionized water is added as solvent, the ratio of safflower to solvent is 1:20, and ultrasonic treatment is carried out at 20°C for 2 hours with an ultrasonic working frequency of 35KHz to obtain safflower natural dye extract.

[0042] Example 1

[0043] (1) Using benzophenone (BP) as a photosensitizer and N-(3-dimethylaminopropyl)methacrylamide (DMAPMA) as a hydrophilic monomer, the above raw materials are dissolved in anhydrous ethanol to form a solution. The concentration of the photosensitizer is 2% and the concentration of the monomer is 9%.

[0044] (2) The dried cotton fabric is immersed in the solution obtained in step (1), with a solution-to-cotton fabric mass ratio of 60:1. After immersion for 5 minutes, it is squeezed on a pressure roller at a 60% liquid-to-liquid ratio. The irradiated cotton fabric is then subjected to single-sided irradiation under an ultraviolet irradiation instrument with an ultraviolet irradiation energy of 2.5 J / cm². 2 The conveyor belt speed is 0.05 m / s, and the energy consumption per revolution is 2.5 J / cm. 2 Irradiate for 1 circle.

[0045] (3) Immerse the cotton fabric from step (3) in natural safflower dye extract for 30 minutes. The dyeing bath ratio is 1:40. Soap and wash the fabric. Finally, dry the cotton fabric with double-sided differential dyeing.

[0046] (4) The resulting double-sided differentiated dyed cotton fabric, such as Figure 1 As shown, the double-sided dyeing depth (K / S value) of cotton fabric is 4.8 on the ultraviolet-irradiated side and 0.9 on the non-ultraviolet-irradiated side.

[0047] Comparative Example 1

[0048] (1) The pre-dried cotton fabric was directly immersed in the natural safflower dye extract for 30 minutes, with a dyeing bath ratio of 1:40.

[0049] (2) The resulting dyed cotton fabric is as follows Figure 2 As shown, the double-sided dyeing depth (K / S value) of the cotton fabric is 0.4 for both sides.

[0050] Example 2

[0051] (1) Using benzophenone (BP) as a photosensitizer and N-(3-dimethylaminopropyl)methacrylamide (DMAPMA) as a hydrophilic monomer, the above raw materials are dissolved in anhydrous ethanol to form a solution. The concentration of the photosensitizer is 2% and the concentration of the monomer is 16%.

[0052] (2) The dried cotton fabric is immersed in the solution obtained in step (1), with a solution-to-cotton fabric mass ratio of 60:1. After immersion for 5 minutes, it is squeezed on a pressure roller at a 60% liquid-to-liquid ratio. The irradiated cotton fabric is then subjected to single-sided irradiation under an ultraviolet irradiation instrument with an ultraviolet irradiation energy of 12.5 J / cm². 2 The conveyor belt speed is 0.05 m / s, and the energy consumption per revolution is 2.5 J / cm. 2 Irradiate for 5 cycles.

[0053] (3) Immerse the cotton fabric from step (3) in natural safflower dye extract for 30 minutes. The dyeing bath ratio is 1:40. Soap and wash the fabric. Finally, dry the cotton fabric with double-sided differential dyeing.

[0054] (4) The resulting double-sided differentiated dyed cotton fabric, such as Figure 3 As shown, the double-sided dyeing depth (K / S value) of cotton fabric is 10.4 on the side exposed to ultraviolet light and 0.9 on the side not exposed to ultraviolet light.

[0055] Example 3

[0056] (1) Using benzophenone (BP) as a photosensitizer and N-(3-dimethylaminopropyl)methacrylamide (DMAPMA) as a hydrophilic monomer, the above raw materials are dissolved in anhydrous ethanol to form a solution. The concentration of the photosensitizer is 2% and the concentration of the monomer is 16%.

[0057] (2) The dried cotton fabric is immersed in the solution obtained in step (1) at a mass ratio of 60:1. After immersion for 5 minutes, it is then squeezed on a pressure roller at a 60% liquid-to-liquid ratio. The irradiated cotton fabric is then subjected to single-sided irradiation under an ultraviolet irradiation instrument with an ultraviolet irradiation energy of 20 J / cm². 2 The conveyor belt speed is 0.05 m / s, and the energy consumption per revolution is 2.5 J / cm. 2 That is, irradiate for 8 cycles.

[0058] (3) Immerse the cotton fabric from step (3) in natural safflower dye extract for 30 minutes. The dyeing bath ratio is 1:60. Soak and wash the fabric with water. Finally, dry the cotton fabric with double-sided differential dyeing.

[0059] (4) The resulting double-sided differentiated dyed cotton fabric, such as Figure 4 As shown, the double-sided dyeing depth (K / S value) of cotton fabric is 6.2 on the side exposed to ultraviolet light and 0.7 on the side not exposed to ultraviolet light.

Claims

1. A method for double-sided differentiated environmentally friendly dyeing of cotton fabrics, characterized in that, Includes the following steps: (1) Dissolve the hydrophilic monomer and the photosensitizing initiator in a solvent to prepare a solution; (2) Immerse the cotton fabric in the solution obtained in step (1), and then place the immersed cotton fabric on the pressure roller for squeezing; (3) The cotton fabric squeezed in step (2) is subjected to single-sided irradiation under an ultraviolet irradiation instrument; the ultraviolet irradiation energy is 2.5~20J / cm. 2 ; (4) The cotton fabric obtained in step (3) is immersed in natural safflower dye extract to obtain cotton fabric with double-sided differential dyeing. In step (1), the photosensitizer is benzophenone; the hydrophilic monomer is N-(3-dimethylaminopropyl)methacrylamide.

2. The method according to claim 1, characterized in that, In step (1), the solvent is ethanol; the mass concentration of the photosensitizer is 2-10%; and the mass concentration of the hydrophilic monomer is 2-22%.

3. The method according to claim 1, characterized in that, In step (2), the cotton fabric is a dried cotton fabric, and the drying conditions are: temperature of 40-50℃ and time of 20-30min.

4. The method according to claim 1, characterized in that, In step (2), the mass ratio of the solution to the cotton fabric is 50:1 to 70:1, the immersion time is 3 to 5 minutes, and the squeezing rate is 50 to 60%.

5. The method according to claim 1, characterized in that, Step (3), the ultraviolet irradiation energy is 2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20 J / cm. 2 One of them.

6. The method according to claim 1, characterized in that, In step (4), the method for preparing the safflower natural dye extract is as follows: safflower is washed and dried, solvent is added, and ultrasonic treatment is performed to obtain the safflower natural dye extract; the extraction solvent used is deionized water, the ratio of safflower to solvent is 1:15 to 1:25, the working frequency of the ultrasonic treatment is 30-40KHz, the temperature is room temperature, and the extraction time is 100-120min.

7. The method according to claim 1, characterized in that, In step (4), the staining bath ratio is 1:30 to 80.

8. The method according to claim 7, characterized in that, In step (4), the staining bath ratio is one of 1:30, 1:40, 1:50, 1:60, 1:70, or 1:

80.

9. The method according to claim 1, characterized in that, In step (4), the soaking time is 30 to 35 minutes.

10. The cotton fabric with double-sided differential dyeing obtained by the method according to any one of claims 1-9.

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