Water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabrics, preparation method and application thereof

Abstract

The present invention relates to a water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabrics, as well as its preparation method and application. The paste is prepared by the following preparation method: first, using polyethylene glycol, toluene diisocyanate, monohydroxy acrylic acid, and dimethylol propionic acid as raw materials, a water-based polyurethane emulsion is prepared; second, peach gum is chemically modified to prepare modified peach gum; then, the modified peach gum is dissolved in an organic solvent to prepare a peach gum emulsion; and finally, the prepared polyurethane emulsion and the peach gum emulsion are mixed in a high-speed dispersing homogenizer to prepare a water-based polyurethane / peach gum composite paste. The water-based polyurethane / peach gum composite paste prepared by the present invention is used for acid dye printing of nylon fabrics. The printed fabrics produced exhibit a de-paste rate exceeding 91%, good softness, high definition, a permeability exceeding 91%, and high dry rubbing color fastness and soaping color fastness, and thus have excellent application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of paste preparation, and particularly relates to a water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabrics, and a preparation method and application thereof. Background Art

[0002] Printing paste refers to a polymer compound that thickens the colorant and can be dispersed in water to form a thick, colloidal solution of a certain concentration. In the actual textile printing process, the paste is the carrier that transfers the dyes and chemicals from the printing paste to the fabric and is the main component of the printing paste. While many factors affect printing quality, the properties of the printing paste largely determine the final printing effect of the fabric and are the key factor affecting the printing effect.

[0003] Nylon is a polymer material containing characteristic amide bonds in its main chain. Its dyeing properties are similar to those of wool and are typically dyed with disperse dyes, acid dyes, and neutral dyes. The dyeing mechanism for nylon fibers using acid dyes is as follows: acid dyes bind to the terminal amino groups of nylon through strong ionic bonds or electrostatic attraction, resulting in vibrant colors with excellent color fastness.

[0004] Synthetic water-based or solvent-based polyurethanes generally use acetone, butanone, toluene, and ethyl acetate as the main solvents. The addition of solvents poses a fire or explosion hazard during production, storage, transportation, and use. In addition, the strong odor and volatility can pollute the surrounding environment, so solvent-based polyurethanes have gradually faded from the market. Water-based polyurethanes use water as the dispersion system. A small amount of solvent is used in the synthesis stage, but the solvent is removed in the later process (generally by vacuum distillation recovery). Hydrophilic groups are introduced into the molecular chain or emulsifiers are added. Under high-speed shear, they are dispersed in water to form a stable emulsion that is non-toxic, harmless, non-flammable, and environmentally friendly. Polyurethane emulsions are widely used in the textile field. By adjusting different raw monomers and compositions, they can give fabrics many unique properties, such as hydrophobicity, UV resistance, windproofness, and antistatic properties. The application performance of water-based polyurethane in the field of printing pastes can be adjusted by designing its molecular structure.

[0005] Peach gum, also known as peach gum, is a colloid, translucent substance secreted by the trunks of plants in the Rosaceae family, such as peach, mountain peach, cherry, plum, and apricot, after mechanical trauma (such as insect bites or cuts) or disease. The solid substance mixed with impurities formed by air-drying or other dehydration methods on the trunk is called raw peach gum. It is a reddish-brown, yellowish-brown, light yellow, or white translucent solid block with a smooth surface. It generally swells but does not dissolve completely. Its aqueous solution is viscous. It is a polysaccharide. Its polysaccharides are mainly composed of galactose and arabinose; it also contains small amounts of mannose, rhamnose, and glucose. It also contains small amounts of protein and impurities. Raw peach gum has low industrial application value due to its difficulty in dispersion and dissolution. However, commercial peach gum obtained through hydrolysis or chemical modification has sufficient water solubility and appropriate viscosity. It is currently used in food, medicine, chemicals, cosmetics, printing and dyeing, electronics, and other fields. Literature research shows that although peach gum has received widespread attention in many fields, its use in printing pastes has rarely been reported and needs further exploration.

[0006] Currently, acid dye printing on nylon fabrics typically uses guar gum, tamarind gum, and synthetic polyurethane thickeners. However, guar gum and tamarind gum are relatively expensive, while synthetic polyurethane thickeners have a low de-paste rate, necessitating the search for alternative pastes. Peach gum and water-based polyurethane are potential materials for pastes. However, peach gum or water-based polyurethane alone are difficult to form into pastes, cannot evenly disperse chemical additives within the colloid system, and exhibit significant viscosity fluctuations upon dilution. These disadvantages limit their application in printing pastes, necessitating technological solutions. The structural characteristics of peach gum and water-based polyurethane suggest their potential as pastes; if their properties complement each other, their applications in the paste field could be further enhanced. Summary of the Invention

[0007] In view of the above-mentioned drawbacks in the prior art, the object of the present invention is to provide a water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabrics, and a preparation method and application thereof.

[0008] The present invention aims to provide a water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabric. The paste is prepared by the following preparation method: first, using polyethylene glycol, toluene diisocyanate, monohydroxy acrylic acid and dimethylol propionic acid as raw materials to prepare a water-based polyurethane emulsion; secondly, chemically modifying peach gum to prepare modified peach gum; then, dissolving the modified peach gum in an organic solvent to prepare a peach gum emulsion; and finally, mixing the prepared polyurethane emulsion and the peach gum emulsion in a high-speed dispersing homogenizer to prepare the water-based polyurethane / peach gum composite paste.

[0009] The object of the present invention is to provide a method for preparing an aqueous polyurethane / peach gum composite paste for acid dye printing of nylon fabric, the specific method comprising the following steps:

[0010] (1) Preparation of waterborne polyurethane emulsion: polyethylene glycol and dihydroxymethylpropionic acid are added to a reaction kettle, vacuum dehydrated at 100-120°C for 1-2 hours, slowly cooled to 50-60°C, toluene diisocyanate, butanone and catalyst dibutyltin dilaurate are added dropwise, the temperature is raised to 80-90°C, and the reaction is carried out for 3-4 hours; the reaction kettle is cooled to 40-45°C, and monohydroxy acrylic acid is added in multiple portions within 1-1.5 hours; the temperature is raised to 60-80°C, and the reaction is kept warm for 1-2 hours; the reaction liquid is reversely emulsified using a high shear rate emulsification pump, and triethylamine is added dropwise for neutralization; the emulsion is subjected to reduced pressure and low temperature distillation to remove butanone, thereby obtaining a waterborne polyurethane emulsion.

[0011] Furthermore, the molecular weight of the polyethylene glycol is 2000, the molar ratio of polyethylene glycol, dimethylolpropionic acid, and toluene diisocyanate is 1:1-2:3-5, the amount of dibutyltin dilaurate is 0.01-0.1% of the total monomer amount, the volume mass ratio of butanone (mL) to the total monomer amount (g) is 1:1-3; the molar ratio of monohydroxy acrylic acid to dimethylolpropionic acid is 1:3-5; and the shear rate of the emulsification pump is 6000-15000 r / min.

[0012] (2) Modification of peach gum: The peach gum was swelled in glacial acetic acid for 2 to 4 hours, and then dissolved in a mixed solution of acetic anhydride and acetic acid. Sulfuric acid was added dropwise to the reaction solution and reacted at 55°C for 2 to 5 hours. After the reaction, the reaction solution was neutralized with a NaOH aqueous solution to a pH of 7 to 8. The reactants were then poured into distilled water to precipitate the modified peach gum. The modified peach gum was centrifuged and washed several times until it was neutral, and then vacuum dried to obtain the modified peach gum.

[0013] Furthermore, the volume ratio of acetic anhydride to acetic acid is 1:1-1.2, the amount of sulfuric acid is 1.0-1.2% of the total volume of acetic anhydride and acetic acid; the amount ratio of peach gum (g) to glacial acetic acid (mL) is: 1:10-12.

[0014] (3) Preparation of peach gum emulsion: Dissolve modified peach gum in dichloromethane to obtain a clear and transparent solution, add Span 80 to the solution, stir and mix, and add the mixture into an aqueous solution of sodium lauryl sulfate to obtain peach gum emulsion;

[0015] Furthermore, the usage ratio of peach gum (g), Span 80 (g) and dichloromethane (mL) is 1:0.1-0.2:10-12, the volume ratio of dichloromethane to sodium dodecyl sulfate aqueous solution is 1:3-5; and the mass fraction of sodium dodecyl sulfate in the sodium dodecyl sulfate aqueous solution is 0.5-1.0%.

[0016] (4) Mixing of emulsions: The polyurethane emulsion prepared in step (1) is mixed with the peach gum emulsion prepared in step (3), and the mixed solution is stirred on a high-speed dispersing homogenizer for 0.5 to 1 hour at room temperature to obtain a water-based polyurethane / peach gum composite paste.

[0017] Furthermore, the volume ratio of the polyurethane emulsion prepared in step (1) to the peach gum emulsion prepared in step (3) is 1:1-2.

[0018] Another object of the present invention is to provide an application of an aqueous polyurethane / peach gum composite paste for acid dye printing on nylon fabrics. The application method comprises the following steps: weighing dyes and chemicals according to a color paste recipe, dissolving an acid dye and sodium chloride in distilled water, and mixing them uniformly to dissolve them; finally, adding the aqueous polyurethane / peach gum composite paste, stirring uniformly, and adjusting the pH of the solution to 5-6 with acetic acid to prepare a color paste for acid dye printing on nylon fabrics; and printing the prepared color paste on nylon fabrics.

[0019] Furthermore, the color paste recipe is: 24-26 g of the waterborne polyurethane / peach gum composite paste prepared by the present invention; 2.2-2.4 g of acid dye; 3-5 g of sodium chloride; and adding water to 100 g.

[0020] Furthermore, the acid dye is any one of CI Acid Orange 7, CI Acid Yellow 11, CI Acid Yellow 17, CI Acid Yellow 36, and CI Acid Red 14, and all acid dyes are named according to international index numbers.

[0021] Furthermore, the printing process is: flat screen printing (scrape printing once) → drying (100° C., 3 min) → steaming (10 min) → cold water rinsing twice → soap washing → cold water washing → drying.

[0022] The present invention has the following significant advantages:

[0023] (1) The aqueous polyurethane / peach gum composite paste prepared by the present invention is used for acid dye printing of nylon fabrics. The printed fabrics prepared have the advantages of a de-pasting rate higher than 91%, good softness, high outline clarity, a permeability higher than 91%, and high dry friction color fastness and soap washing color fastness, etc., and have good application prospects.

[0024] (2) The inventors of the present application unexpectedly discovered that the prepared aqueous polyurethane / peach gum composite paste contains aqueous polyurethane emulsion and peach gum emulsion, which achieves complementary advantages and disadvantages, making it have obvious advantages in the field of printing paste.

[0025] (3) The aqueous polyurethane / peach gum composite paste prepared by the present invention contains a large amount of carboxylic acid radicals and hydrophilic side chains, which significantly improves the wetting performance of the paste, i.e., it wets the fabric well. In addition, it has good paste-forming properties, and the viscosity of the paste changes little when it is diluted.

[0026] (4) The present invention achieves that the composite paste contains appropriate amounts of aqueous polyurethane emulsion and peach gum emulsion by regulating the amounts of the aqueous polyurethane emulsion and the peach gum emulsion, thereby achieving the purpose of the paste uniformly dispersing the dye and the chemical additives in the colloid system; in addition, the paste has a certain pressure permeability after being made into a printing paste, and has moderate permeability to the fabric, so that the paste can penetrate into the interior of the fabric.

[0027] (5) The examples show that the performance of the aqueous polyurethane / peach gum composite paste prepared by the present invention is significantly better than that of a single aqueous polyurethane emulsion or peach gum emulsion; an appropriate amount of aqueous polyurethane emulsion or peach gum emulsion is beneficial to improving its printing performance. DETAILED DESCRIPTION

[0028] The following examples and comparative examples illustrate the present invention in detail.

[0029] Source of main raw materials: Acid dye CI Acid Yellow 11 was purchased from Tianjin Shengda Ruitai Technology Development Co., Ltd.

[0030] Example 1

[0031] The preparation method of the water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabric comprises the following steps:

[0032] (1) Preparation of waterborne polyurethane emulsion: 0.1 mol of polyethylene glycol with a molecular weight of 2000 and 0.15 mol of dihydroxymethylpropionic acid were added to a reactor, vacuum dehydrated at 110°C for 1.5 h, slowly cooled to 55°C, 0.4 mol of toluene diisocyanate, 65 mL of butanone and 1.3 g of catalyst dibutyltin dilaurate were added dropwise, the temperature was raised to 85°C, and the reaction was carried out for 3.5 h; the reactor was cooled to 43°C, and 0.125 mol of monohydroxy acrylic acid was added in multiple times within 1.2 h; the temperature was raised to 70°C and the reaction was kept warm for 1.5 h; the reaction liquid was reversely emulsified using an emulsification pump with a shear rate of 10,000 r / min, and triethylamine was added dropwise for neutralization; the butanone was removed from the emulsion by vacuum low-temperature distillation to obtain a waterborne polyurethane emulsion.

[0033] (2) Modification of peach gum: 10 g of peach gum was swelled in 110 mL of glacial acetic acid for 3 h, then dissolved in a mixed solution of 50 mL of acetic anhydride and 55 mL of acetic acid, 1.1 mL of sulfuric acid was added dropwise to the reaction solution, and the reaction was carried out at 55°C for 3.5 h. After the reaction was completed, the reaction solution was neutralized with a NaOH aqueous solution to a pH of 7.5, and then the above reactants were poured into 500 mL of distilled water to precipitate the modified peach gum. Finally, the obtained modified peach gum was centrifuged and rinsed several times until it was neutral, and then vacuum dried to obtain the modified peach gum.

[0034] (3) Preparation of peach gum emulsion: 10 g of modified peach gum was dissolved in 110 mL of dichloromethane to obtain a clear and transparent solution. 1.5 g of Span 80 was added to the solution and stirred to mix thoroughly. The mixture was then added to 440 mL of a 0.75% sodium lauryl sulfate aqueous solution to obtain a peach gum emulsion.

[0035] (4) Mixing of emulsions: 100 mL of the polyurethane emulsion prepared in step (1) was mixed with 150 mL of the peach gum emulsion prepared in step (3), and the mixed solution was stirred on a high-speed dispersing homogenizer for 0.75 h at room temperature to obtain a water-based polyurethane / peach gum composite paste.

[0036] The invention discloses an application of an aqueous polyurethane / peach gum composite paste for acid dye printing on nylon fabric. The application method comprises the following steps: selecting a color paste recipe comprising: 25 g of the aqueous polyurethane / peach gum composite paste prepared in this embodiment; 2.3 g of an acid dye; and 4 g of sodium chloride; adding water to make up to 100 g; weighing dyes and chemicals according to the color paste recipe, dissolving the acid dye CI Acid Yellow 11 and the sodium chloride in distilled water, and mixing them uniformly to dissolve them; finally, adding the aqueous polyurethane / peach gum composite paste, stirring uniformly, and adjusting the pH of the solution to 5.5 with acetic acid to obtain a color paste for acid dye printing on nylon fabric; and printing the obtained color paste on nylon fabric. The printing process comprises the following steps: flat screen printing (scrape printing once) → drying (100°C, 3 min) → steaming (10 min) → cold water rinsing twice → soaping → cold water washing → drying.

[0037] Example 2

[0038] The preparation method of the water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabric comprises the following steps:

[0039] (1) Preparation of waterborne polyurethane emulsion: 0.1 mol of polyethylene glycol with a molecular weight of 2000 and 0.1 mol of dihydroxymethylpropionic acid were added to a reactor, vacuum dehydrated at 100°C for 1.0 h, slowly cooled to 50°C, 0.3 mol of toluene diisocyanate, 95.6 mL of butanone and 0.478 g of catalyst dibutyltin dilaurate were added dropwise, the temperature was raised to 80°C, and the reaction was carried out for 3.0 h; the reactor was cooled to 40°C, and 0.1 mol of monohydroxy acrylic acid was added three times within 1.0 h; the temperature was raised to 60°C and the reaction was kept warm for 1.0 h; the reaction liquid was reversely emulsified using an emulsification pump with a shear rate of 6000 r / min, and triethylamine was added dropwise for neutralization; the butanone was removed from the emulsion by vacuum low-temperature distillation to obtain a waterborne polyurethane emulsion.

[0040] (2) Modification of peach gum: 10 g of peach gum was swelled in 100 mL of glacial acetic acid for 3 h, then dissolved in a mixed solution of 50 mL of acetic anhydride and 50 mL of acetic acid, 1.0 mL of sulfuric acid was added dropwise to the reaction solution, and the reaction was carried out at 55°C for 2 h. After the reaction was completed, the reaction solution was neutralized with a NaOH aqueous solution to a pH of 7.0, and then the above reactants were poured into 500 mL of distilled water to precipitate the modified peach gum. Finally, the obtained modified peach gum was centrifuged and rinsed several times until it was neutral, and then vacuum dried to obtain the modified peach gum.

[0041] (3) Preparation of peach gum emulsion: 10 g of modified peach gum was dissolved in 100 mL of dichloromethane to obtain a clear and transparent solution. 1.0 g of Span 80 was added to the solution and stirred to mix thoroughly. The mixture was then added to 400 mL of a 0.5% sodium lauryl sulfate aqueous solution to obtain a peach gum emulsion.

[0042] (4) Mixing of emulsions: 100 mL of the polyurethane emulsion prepared in step (1) was mixed with 100 mL of the peach gum emulsion prepared in step (3), and the mixed solution was stirred on a high-speed dispersing homogenizer for 0.75 h at room temperature to obtain a water-based polyurethane / peach gum composite paste.

[0043] The invention discloses an application of an aqueous polyurethane / peach gum composite paste for acid dye printing on nylon fabric. The application method comprises the following steps: selecting a color paste recipe comprising: 24 g of the aqueous polyurethane / peach gum composite paste prepared in this embodiment; 2.2 g of an acid dye; and 3 g of sodium chloride; adding water to make up to 100 g; weighing dyes and chemicals according to the color paste recipe, dissolving the acid dye CI Acid Yellow 11 and the sodium chloride in distilled water, and mixing them uniformly to dissolve them; finally, adding the aqueous polyurethane / peach gum composite paste, stirring uniformly, and adjusting the pH of the solution to 5.5 with acetic acid to obtain a color paste for acid dye printing on nylon fabric; and printing the obtained color paste on nylon fabric. The printing process comprises the following steps: flat screen printing (scrape printing once) → drying (100°C, 3 min) → steaming (10 min) → cold water rinsing twice → soaping → cold water washing → drying.

[0044] Example 3

[0045] The preparation method of the water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabric comprises the following steps:

[0046] (1) Preparation of waterborne polyurethane emulsion: 0.1 mol of polyethylene glycol with a molecular weight of 2000 and 0.2 mol of dihydroxymethylpropionic acid were added to a reactor, vacuum dehydrated at 120°C for 2 h, slowly cooled to 60°C, 0.5 mol of toluene diisocyanate, 51.3 mL of butanone and 2.3 g of catalyst dibutyltin dilaurate were added dropwise, the temperature was raised to 90°C, and the reaction was carried out for 4 h; the reactor was cooled to 45°C, and 0.2 mol of monohydroxy acrylic acid was added three times within 1.5 h; the temperature was raised to 80°C and the reaction was kept warm for 2 h; the reaction liquid was reversely emulsified using an emulsification pump with a shear rate of 15000 r / min, and triethylamine was added dropwise for neutralization; the butanone was removed from the emulsion by vacuum low-temperature distillation to obtain a waterborne polyurethane emulsion.

[0047] (2) Modification of peach gum: 10 g of peach gum was swelled in 120 mL of glacial acetic acid for 3 h, then dissolved in a mixed solution of 50 mL of acetic anhydride and 60 mL of acetic acid, 1.2 mL of sulfuric acid was added dropwise to the reaction solution, and the reaction was carried out at 55°C for 5 h. After the reaction was completed, the reaction solution was neutralized with a NaOH aqueous solution to a pH of 8, and then the above reactants were poured into 500 mL of distilled water to precipitate the modified peach gum. Finally, the obtained modified peach gum was centrifuged and rinsed several times until it was neutral, and then vacuum dried to obtain the modified peach gum.

[0048] (3) Preparation of peach gum emulsion: 10 g of modified peach gum was dissolved in 120 mL of dichloromethane to obtain a clear solution. 2.0 g of Span 80 was added to the solution and stirred to mix thoroughly. The mixture was then added to 480 mL of a 1.0% sodium lauryl sulfate aqueous solution to obtain a peach gum emulsion.

[0049] (4) Mixing of emulsions: 100 mL of the polyurethane emulsion prepared in step (1) was mixed with 200 mL of the peach gum emulsion prepared in step (3), and the mixed solution was stirred on a high-speed dispersing homogenizer for 0.75 h at room temperature to obtain a water-based polyurethane / peach gum composite paste.

[0050] The invention discloses an application of an aqueous polyurethane / peach gum composite paste for acid dye printing on nylon fabric. The application method comprises the following steps: selecting a color paste recipe comprising: 26 g of the aqueous polyurethane / peach gum composite paste prepared in this embodiment; 2.4 g of an acid dye; and 5 g of sodium chloride; adding water to make up to 100 g; weighing dyes and chemicals according to the color paste recipe, dissolving the acid dye CI Acid Yellow 11 and the sodium chloride in distilled water, and mixing them uniformly to dissolve them; finally, adding the aqueous polyurethane / peach gum composite paste, stirring uniformly, and adjusting the pH of the solution to 5.5 with acetic acid to obtain a color paste for acid dye printing on nylon fabric; and printing the obtained color paste on nylon fabric using the following printing process: flat screen printing (scrape printing once) → drying (100°C, 3 min) → steaming (10 min) → cold water rinsing twice → soaping → cold water washing → drying.

[0051] Comparative Example A

[0052] Taking Example 1 as a comparison, step (1) was not implemented, and the peach gum emulsion prepared in step (3) was directly used for the paste; other preparation methods and application methods remained unchanged from Example 1.

[0053] Comparative Example B

[0054] Taking Example 1 as a comparison, steps (2) and (3) are not implemented, and the aqueous polyurethane emulsion prepared in step (1) is directly used for the paste; other preparation methods and application methods remain unchanged from Example 1.

[0055] Comparative Example C

[0056] Taking Example 1 as a comparison, the "100 mL of the polyurethane emulsion prepared in step (1)" in step (4) was reduced to "10 mL of the polyurethane emulsion prepared in step (1)"; the other preparation methods and application methods remained unchanged from Example 1.

[0057] Comparative Example D

[0058] Taking Example 1 as a comparison, the "100 mL of the polyurethane emulsion prepared in step (1)" in step (4) is increased to "1000 mL of the polyurethane emulsion prepared in step (1)"; the other preparation methods and application methods remain unchanged from Example 1.

[0059] Comparative Example E

[0060] DNY textile printing paste (produced by Hubei Daya Biotechnology Co., Ltd.) purchased from the market was used as the paste in this example. The method of Example 1 was used to prepare a color paste and print on nylon fabric.

[0061] Application performance testing:

[0062] The viscosity of the pastes prepared in Examples 1-3 and Comparative Examples AE was tested using a digital viscometer.

[0063] PVI= h6

[0064] Index (PVI value): η 0.6 , where η6 and η 0.6 They represent the viscosity of the paste at 6 r / min and 0.6 r / min respectively. The test results are shown in Table 1.

[0065] The printed nylon fabrics prepared in Examples 1-3 and Comparative Examples AE were subjected to relevant tests: the K / S value was measured using a computer colorimeter, and the permeability was expressed as the ratio of the K / S value of the back side of the fabric to the K / S value of the front side; the color fastness to washing was tested in accordance with GB / T3921-2008 "Textiles - Tests for Color Fastness - Color Fastness to Washing"; the dry rubbing fastness was tested in accordance with GB / T3920-2008 "Textiles - Tests for Color Fastness - Color Fastness to Rubbing"; the de-pasting rate was calculated as follows: m1 is the mass of the fabric after printing and drying, m2 is the mass of the printed fabric after washing, and m0 is the mass of the unprinted fabric; Fabric softness test: The softness of the printed fabric was tested on a fabric style meter; Contour clarity test: The clarity level was assessed by visual inspection; the test results are shown in Table 1:

[0066] Table 1 Evaluation of the application performance of waterborne polyurethane / peach gum composite paste for acid dye printing of nylon fabric

[0067]

[0068] As can be seen from Table 1, by comparing Example 1 and Comparative Example A, it can be found that the aqueous polyurethane emulsion plays an important role in the printing performance of the aqueous polyurethane / peach gum composite paste. By comparing Example 1 and Comparative Example B, it can be found that the peach gum emulsion plays an important role in the printing performance of the aqueous polyurethane / peach gum composite paste. By comparing Example 1, Comparative Examples C and D, it can be found that the appropriate proportion of aqueous polyurethane emulsion and peach gum emulsion usage plays an important role in the composite paste. By comparing Examples 1-3 and Comparative Example E, it can be found that compared with existing commercial printing pastes on the market, the aqueous polyurethane / peach gum composite paste prepared by the present invention and the nylon fabric after printing thereof all reach or exceed the existing commercial printing pastes on the market and the nylon fabric after printing thereof in many test index values.

Claims

1. A method for preparing a water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabric, characterized in that: The preparation method comprises the following steps: (1) Preparation of waterborne polyurethane emulsion: polyethylene glycol and dihydroxymethylpropionic acid were added to a reaction kettle, vacuum dehydrated at 100-120°C for 1-2 hours, slowly cooled to 50-60°C, and toluene diisocyanate, butanone and catalyst dibutyltin dilaurate were added dropwise. The temperature was raised to 80-90°C and the reaction was carried out for 3-4 hours. The reaction kettle was cooled to 40-45°C, and monohydroxy acrylic acid was added in multiple portions within 1-1.5 hours. The temperature was raised to 60-80°C and the reaction was kept warm for 1-2 hours. The reaction liquid was reversely emulsified using a high shear rate emulsification pump, and triethylamine was added dropwise for neutralization. The butanone was removed from the emulsion by vacuum low-temperature distillation to obtain a waterborne polyurethane emulsion. (2) Modification of peach gum: The peach gum was swelled in glacial acetic acid for 2-4 hours, then dissolved in a mixed solution of acetic anhydride and acetic acid, sulfuric acid was added dropwise to the reaction solution, and the reaction was carried out at 55°C for 2-5 hours. After the reaction was completed, the reaction solution was neutralized with a NaOH aqueous solution to a pH of 7-8, and then the reactants were poured into distilled water to precipitate the modified peach gum. Finally, the obtained modified peach gum was centrifuged and washed several times until it was neutral, and then vacuum dried to obtain the modified peach gum. (3) Preparation of peach gum emulsion: Dissolve the modified peach gum in dichloromethane to obtain a clear and transparent solution, add Span 80 to the solution, stir and mix evenly, and add the mixture into an aqueous solution of sodium dodecyl sulfate to obtain peach gum emulsion; (4) Mixing the emulsions: Mix the polyurethane emulsion prepared in step (1) with the peach gum emulsion prepared in step (3), and stir the mixed solution in a high-speed dispersing homogenizer for 0.5 to 1 hour at room temperature to obtain a water-based polyurethane / peach gum composite paste; In the step (1), the molecular weight of polyethylene glycol is 2000; the molar ratio of polyethylene glycol, dimethylol propionic acid, and toluene diisocyanate is 1:(1-2):(3-5); the amount of dibutyltin dilaurate is 0.01-0.1wt% of the total monomer amount; the volume mass ratio of butanone to the total monomer amount is 1mL:(1-3)g; the molar ratio of monohydroxy acrylic acid to dimethylol propionic acid is 1:(3-5); the shear rate of the emulsification pump is 6000-15000r / min; In step (3), the dosage ratio of peach gum, Span 80 and dichloromethane is 1 g: (0.1-0.2) g: (10-12) mL, and the volume ratio of dichloromethane to sodium dodecyl sulfate aqueous solution is 1: (3-5); the mass fraction of sodium dodecyl sulfate in the sodium dodecyl sulfate aqueous solution is 0.5-1.0 wt%; In the step (4), the volume ratio of the polyurethane emulsion prepared in step (1) to the peach gum emulsion prepared in step (3) is 1:(1-2).

2. The preparation method of the aqueous polyurethane / peach gum composite paste for nylon fabric acid dye printing according to claim 1, wherein In step (2), the volume ratio of acetic anhydride to acetic acid is 1: (1-1.2), the amount of sulfuric acid used is 1.0-1.2 v / v% of the total volume of acetic anhydride and acetic acid; and the amount ratio of peach gum to glacial acetic acid is 1 g: (10-12) mL.

3. A water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabric, characterized in that: The invention is prepared by the method for preparing the water-based polyurethane / peach gum composite paste for acid dye printing of nylon fabrics according to any one of claims 1 to 2.

4. An application of the aqueous polyurethane / peach gum composite paste for acid dye printing of nylon fabric as claimed in claim 3, characterized in that: The application method comprises the following steps: weighing dyeing materials according to a color paste recipe, dissolving acid dyes and sodium chloride with distilled water, and mixing them evenly to dissolve them; finally, adding a water-based polyurethane / peach gum composite paste, stirring evenly, and adjusting the pH of the solution to 5-6 with acetic acid to prepare a color paste for acid dye printing on nylon fabrics; and printing the prepared color paste on nylon fabrics.

5. The use of the aqueous polyurethane / peach gum composite paste for acid dye printing of nylon fabric according to claim 4, characterized in that: The color paste formula is: water-based polyurethane / peach gum composite paste: 24-26g; Acid dye: 2.2-2.4g; Sodium chloride: 3-5g; Add water to 100g.

6. The use of the aqueous polyurethane / peach gum composite paste for acid dye printing of nylon fabric according to claim 4, characterized in that: The acid dye is any one of CI Acid Orange 7, CI Acid Yellow 11, CI Acid Yellow 17, CI Acid Yellow 36, and CI Acid Red 14. All acid dyes are named according to international index numbers.

7. The use of the aqueous polyurethane / peach gum composite paste for acid dye printing of nylon fabric according to claim 4, characterized in that: The printing process is as follows: flat screen printing, scraping once → drying at 100° C. for 3 minutes → steaming for 10 minutes → cold water rinsing twice → soap washing → cold water washing → drying.

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