Sulfonic acid type anionic waterborne polyurethane fixing agent and preparation method thereof

Abstract

This invention discloses a sulfonic acid-based anionic waterborne polyurethane fixing agent and its preparation method. The method includes the following steps: 1. Take 60-120 parts by weight of diol, 5-15 parts by weight of sulfonic acid chain extender, 45-65 parts by weight of diisocyanate, 1-5 parts by weight of trimethylolpropane, 5-10 parts by weight of 1,4-butanediol and 600-900 parts by weight of deionized water for later use; 2. First, vacuum dry and dehydrate the diol and sulfonic acid chain extender, then add them together with diisocyanate to a three-necked flask, and stir and react at 70-90°C for 1-3 h to obtain a prepolymer; 3. Add trimethylolpropane to the prepolymer at 70-90°C, and crosslink the reaction for 1-2 h, then add 1,4-butanediol, and extend the chain for 1-2 h, then cool naturally to room temperature, and add deionized water under high-speed stirring, and emulsify for 30-60 min to obtain the sulfonic acid-based anionic waterborne polyurethane fixing agent. The sulfonic acid-type anionic waterborne polyurethane fixing agent prepared by this invention has excellent film-forming properties and the film has good water resistance, which significantly improves the color fastness of fabrics.

Description

Technical Field

[0001] This invention relates to color-fixing agents, specifically a sulfonic acid-type anionic waterborne polyurethane color-fixing agent and its preparation method. Background Technology

[0002] In the textile industry, nylon (commonly known as polyamide) is renowned for its excellent elasticity, abrasion resistance, and comfort, and is widely used in a range of apparel, from swimwear to sportswear. Acid dyes, especially weakly acidic dyes, offer a broad color spectrum and vibrant hues, making them particularly important in nylon dyeing. However, due to the presence of water-soluble groups such as amino and sulfonic acid groups in acid dyes, nylon fabrics dyed with acid dyes often exhibit poor wash fastness. In recent years, traditional fixing agents have been gradually phased out due to the presence of toxic components such as free formaldehyde and bisphenol. Developing novel formaldehyde-free fixing agents to improve the color fastness of nylon dyed with acid dyes has become a current research hotspot.

[0003] Waterborne polyurethane (WPU) can achieve good water solubility by introducing hydrophilic chain extenders. It can be directly emulsified and dispersed in water without the addition of external emulsifiers. It is an environmentally friendly material with broad application prospects. At present, WPU has been widely used in color fixing of textiles such as nylon and cotton fabrics and leather due to its unique block structure and excellent flexibility, abrasion resistance and film-forming properties.

[0004] Sulfonic acid anionic WPU is a hydrophilic fixing agent prepared by introducing a hydrophilic chain extender containing sulfonic acid groups into WPU. The sulfonic acid groups endow the fixing agent with excellent water dispersibility. After film formation, the sulfonic acid groups form a negatively charged layer on the fiber surface, generating electrostatic repulsion against acidic dye anions attempting to migrate, thereby inhibiting dye dissolution and migration. However, due to the hydrophilicity of the hydrophilic sulfonic acid groups, the WPU film easily absorbs water and swells, leading to a decrease in wet treatment fastness such as washing and immersion color fastness, limiting the application scenarios of sulfonic acid anionic WPU in high-humidity, high-washing-requirement environments. Summary of the Invention

[0005] The purpose of this invention is to provide a sulfonic acid-based anionic waterborne polyurethane fixing agent and its preparation method. The prepared sulfonic acid-based anionic waterborne polyurethane fixing agent has excellent film-forming properties and the film has good water resistance, which significantly improves the color fastness of nylon fabrics.

[0006] This invention is achieved through the following technical solution: A sulfonic acid-based anionic waterborne polyurethane fixing agent, comprising the following steps: Step 1: Take 60-120 parts by weight of diol, 5-15 parts by weight of sulfonic acid chain extender, 45-65 parts by weight of diisocyanate, 1-5 parts by weight of trimethylolpropane, 5-10 parts by weight of 1,4-butanediol and 600-900 parts by weight of deionized water for later use. Step 2: First, the diol and sulfonic acid chain extender are vacuum dried and dehydrated, and then added together with diisocyanate into a three-necked flask. The mixture is stirred and reacted at 70~90℃ for 1~3 h to obtain the prepolymer. Step 3: At 70~90℃, add trimethylolpropane to the prepolymer and crosslink it for 1~2 h. Then add 1,4-butanediol and extend the chain for 1~2 h. Then cool naturally to room temperature. Under high-speed stirring, add deionized water and emulsify for 30~60 min to obtain sulfonic acid type anionic waterborne polyurethane fixing agent.

[0007] Furthermore, the diol is at least one of polyethylene glycol, polytetrahydrofuran ether glycol, polycaprolactone, and polypropylene glycol, and the molecular weight of the diol is 2000.

[0008] Furthermore, the sulfonic acid chain extender is a sulfonic acid type polyester polyol, sodium diamine sulfonate, or dihydroxypropanesulfonic acid amine.

[0009] Furthermore, the sulfonic acid type polyester polyol is a small molecule sulfonate diol BY-3306 or sulfonate polyester polyol BY-3305 produced by Beijing Baiyuan Chemical.

[0010] Furthermore, the diisocyanate is isophorone diisocyanate or hexamethylene diisocyanate.

[0011] Furthermore, the high-speed stirring in step 3 uses a rotation speed of 800~1000 r / min.

[0012] A sulfonic acid-based anionic waterborne polyurethane fixing agent.

[0013] The present invention has the following beneficial technical effects: 1) The color-fixing agent prepared by this invention has good film-forming properties, can effectively coat dyes and inhibit their shedding, and has excellent color-fixing effect, which is reflected in: First, the introduced hydrophilic sulfonic acid groups can generate strong electrostatic repulsion with acidic dye anions, hindering dye dissolution and migration, thereby improving the color-fixing effect of the fabric; Second, the introduction of trimethylolpropane increases the cross-linking degree of polyurethane molecular chains, making the polyurethane film denser and less prone to water absorption and swelling due to the hydrophilicity of sulfonic acid groups, thus enhancing the water-wash resistance of the water-based polyurethane color-fixing agent film, thereby significantly improving the water resistance and color-fixing performance of the color-fixing agent.

[0014] 2) This invention uses diol, diisocyanate, sulfonic acid chain extender and trimethylolpropane as the main raw materials to prepare sulfonic acid type anionic waterborne polyurethane fixing agent by prepolymer method. It does not contain harmful components including formaldehyde and bisphenol, which fundamentally avoids the potential risks to human health and long-term harm to the ecological environment caused by the presence of harmful components in traditional fixing agents. Attached Figure Description

[0015] Figure 1 Infrared spectrum of the sulfonic acid-type anionic aqueous polyurethane fixing agent prepared in Example 1 of this invention; Figure 2 Microscopic morphology of nylon fabric before and after color fixing by the color-fixing agent prepared in Example 1 of this invention. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0017] The sulfonic acid type polyester polyol selected in this invention is small molecule sulfonate diol BY-3306 or sulfonate polyester polyol BY-3305 produced by Beijing Baiyuan Chemical Co., Ltd.

[0018] Example 1 Step 1: According to the weight parts, take 32 parts of polyethylene glycol-2000, 75 parts of polytetrahydrofuran ether glycol-2000, 12 parts of small molecule sulfonate glycol BY-3306, 50 parts of isophorone diisocyanate, 3 parts of trimethylolpropane, 8 parts of 1,4-butanediol and 800 parts of deionized water, and set aside. Step 2: First, polyethylene glycol-2000, polytetrahydrofuran ether glycol-2000 and molecular sulfonate glycol BY-3306 are vacuum dried and dehydrated. Then, they are added together with isophorone diisocyanate into a three-necked flask and stirred at 80°C for 2 hours to obtain the prepolymer. Step 3: At 80°C, add trimethylolpropane to the prepolymer and crosslink for 2 h. Then add 1,4-butanediol and chain extend for 1 h. Then cool naturally to room temperature, stir at 800 r / min, add deionized water, and emulsify for 30 min to obtain sulfonic acid type anionic waterborne polyurethane fixing agent.

[0019] Example 2 Step 1: According to the weight parts, take 35 parts of polyethylene glycol-2000, 80 parts of polycaprolactone-2000, 10 parts of sodium diamine sulfonate, 60 parts of hexamethylene diisocyanate, 2 parts of trimethylolpropane, 6 parts of 1,4-butanediol and 750 parts of deionized water, and set aside. Step 2: First, polyethylene glycol-2000, polycaprolactone-2000 and sodium diamine sulfonate are vacuum dried and dehydrated. Then, they are added together with hexamethylene diisocyanate into a three-necked flask and stirred at 75°C for 3 hours to obtain the prepolymer. Step 3: At 75°C, trimethylolpropane is added to the prepolymer, and the crosslinking reaction is carried out for 1.5 h. Then, 1,4-butanediol is added, and the chain extension reaction is carried out for 1.5 h. Then, the mixture is naturally cooled to room temperature, stirred at a high speed of 900 r / min, and deionized water is added. The mixture is emulsified for 40 min to obtain a sulfonic acid type anionic waterborne polyurethane fixing agent.

[0020] Example 3 Step 1: According to the weight parts, take 30 parts of polyethylene glycol-2000, 40 parts of polytetrahydrofuran ether glycol-2000, 50 parts of polycaprolactone-2000, 8 parts of dihydroxypropanesulfonic acid amine, 65 parts of isophorone diisocyanate, 5 parts of trimethylolpropane, 5 parts of 1,4-butanediol and 850 parts of deionized water, and set aside. Step 2: First, polyethylene glycol-2000, polytetrahydrofuran ether glycol-2000, polycaprolactone-2000 and dihydroxypropanesulfonic acid amine are vacuum dried and dehydrated. Then, they are added together with isophorone diisocyanate into a three-necked flask and stirred at 90°C for 2.5 h to obtain the prepolymer. Step 3: At 90°C, add trimethylolpropane to the prepolymer and crosslink for 2 h. Then add 1,4-butanediol and chain extend for 2 h. Then cool naturally to room temperature, stir at 1000 r / min, add deionized water, and emulsify for 60 min to obtain sulfonic acid type anionic waterborne polyurethane fixing agent.

[0021] Example 4 Step 1: According to the weight, take 60 parts of polypropylene glycol-2000, 5 parts of sodium diamine sulfonate, 45 parts of hexamethylene diisocyanate, 1 part of trimethylolpropane, 7 parts of 1,4-butanediol and 600 parts of deionized water, and set aside. Step 2: First, dehydrate polypropylene glycol-2000 and sodium diamine sulfonate under vacuum, then add them together with hexamethylene diisocyanate into a three-necked flask and stir at 70°C for 3 hours to obtain the prepolymer. Step 3: At 70°C, trimethylolpropane is added to the prepolymer and the crosslinking reaction is carried out for 2 h. Then, 1,4-butanediol is added and the chain extension reaction is carried out for 2 h. Then, the mixture is naturally cooled to room temperature, stirred at high speed at 850 r / min, and deionized water is added. The mixture is emulsified for 50 min to obtain a sulfonic acid type anionic waterborne polyurethane fixing agent.

[0022] Example 5 Step 1: According to the weight parts, take 60 parts of polycaprolactone-2000, 30 parts of polypropylene glycol-2000, 15 parts of sulfonate polyester polyol BY-3305, 60 parts of isophorone diisocyanate, 4 parts of trimethylolpropane, 9 parts of 1,4-butanediol and 600~900 parts of deionized water, and set aside. Step 2: First, polycaprolactone-2000, polypropylene glycol-2000 and sulfonate polyester polyol BY-3305 are vacuum dried and dehydrated. Then, they are added together with isophorone diisocyanate into a three-necked flask and stirred at 85°C for 2.5 h to obtain the prepolymer. Step 3: At 85°C, trimethylolpropane was added to the prepolymer and the crosslinking reaction was carried out for 1.5 h. Then, 1,4-butanediol was added and the chain extension reaction was carried out for 1.5 h. The mixture was then naturally cooled to room temperature and stirred at a high speed of 950 r / min. Deionized water was added and the mixture was emulsified for 40 min to obtain a sulfonic acid type anionic waterborne polyurethane fixing agent.

[0023] Example 6 Step 1: According to the weight, take 75 parts of polytetrahydrofuran ether diol-2000, 14 parts of sulfonate polyester polyol BY-3305, 55 parts of hexamethylene diisocyanate, 3 parts of trimethylolpropane, 10 parts of 1,4-butanediol and 900 parts of deionized water for later use. Step 2: First, the polytetrahydrofuran ether diol-2000 and sulfonate polyester polyol BY-3305 are vacuum dried and dehydrated. Then, they are added together with hexamethylene diisocyanate into a three-necked flask and stirred at 90°C for 1 h to obtain the prepolymer. Step 3: At 90°C, add trimethylolpropane to the prepolymer and crosslink for 1 h. Then add 1,4-butanediol and chain extend for 1 h. Then cool naturally to room temperature, stir at 1000 r / min, add deionized water, and emulsify for 30 min to obtain sulfonic acid type anionic waterborne polyurethane fixing agent.

[0024] To verify the color-fixing effect of the sulfonic acid-type anionic waterborne polyurethane color-fixing agent prepared in this invention, nylon fabrics were treated with the sulfonic acid-type anionic waterborne polyurethane color-fixing agent prepared in Example 1 and a commercially available color-fixing agent. Nylon fabrics treated with different color-fixing agents were obtained. Nylon fabrics without color-fixing treatment were used as control samples. Then, the color fastness to washing was tested with reference to GB / T 3921-2008 "Textiles - Tests for Color Fastness to Washing", the color fastness to immersion was tested with reference to GB / T 5713-2013 "Textiles - Tests for Color Fastness to Water", and the color fastness to rubbing was tested with reference to GB / T 3920-2008 "Textiles - Tests for Color Fastness to Rubbing". Finally, the color fastness grades were assessed using GB / T250-2008 "Grey Chart for Assessing Color Change" and GB / T251-2008 "Grey Chart for Assessing Staining". See Table 1. Table 1. Color fastness of nylon fabrics after color fastening treatment with different fixing agents As shown in Table 1, the nylon fabric treated with the sulfonic acid-type anionic waterborne polyurethane fixing agent prepared in Example 1 exhibited the best color fastness to washing, immersion, rubbing, and color change grades. The nylon fabric treated with a commercially available fixing agent (anionic acid fixing agent DM-2536 produced by Shaoxing Demei New Materials Co., Ltd.) showed the second best color fastness and color change grades. The nylon fabric without fixing agent treatment (control group) showed the lowest color fastness and color change grades.

[0025] Figure 1 The infrared spectrum of the sulfonic acid-type anionic aqueous polyurethane fixing agent prepared in Example 1 is shown. It can be seen that: 2280-2240 cm⁻¹ -1 No characteristic absorption peak of -NCO was observed nearby, but at 3341 cm⁻¹... -1 The presence of an NH stretching vibration absorption peak at 2947 cm⁻¹ indicates that the -NCO group has fully reacted with the hydroxyl group to form an -NHCOO- bond; -1 and 2857 cm -1 The absorption peaks at 1700 cm⁻¹ are due to the CH stretching vibrations of -CH₃ and -CH₂. -1 1537 cm -1 and 1242 cm -1 The three distinct absorption peaks observed at 1041 cm⁻¹ are attributed to the C=O, CN, and COC stretching vibrations of the -NHCOO- group, respectively; -1 1288 cm -1The characteristic peak at the point is the stretching vibration absorption peak of the SO bond in the sulfonic acid group, indicating that the polyurethane molecular chain contains -SO3 groups; the above results prove that sulfonic acid type anionic waterborne polyurethane was successfully prepared in Example 1.

[0026] Figure 2 The microstructures of nylon fabrics before and after color fixing are shown. (a) to (b) show the microstructures of nylon fabrics before color fixing, and (c) to (d) show the microstructures of nylon fabrics treated with the sulfonic acid anionic waterborne polyurethane color fixing agent prepared in Example 1. It can be seen that the nylon fibers of the unfixed nylon fabric have distinct outlines, are independent of each other, are relatively smooth and do not stick together. However, after color fixing with the sulfonic acid anionic waterborne polyurethane color fixing agent prepared in Example 1, a smooth film is formed on the surface of the nylon fibers, with only a small number of protrusions and wrinkles. The fibers stick together with each other, indicating that the sulfonic acid anionic waterborne polyurethane color fixing agent exhibits excellent film-forming properties and can successfully encapsulate the nylon fibers with acid dye molecules, thereby enhancing its wash resistance and various color fastness properties.

Claims

1. A sulfonic acid-based anionic waterborne polyurethane fixing agent, characterized in that, Includes the following steps: Step 1: Take 60-120 parts by weight of diol, 5-15 parts by weight of sulfonic acid chain extender, 45-65 parts by weight of diisocyanate, 1-5 parts by weight of trimethylolpropane, 5-10 parts by weight of 1,4-butanediol and 600-900 parts by weight of deionized water for later use. Step 2: First, the diol and sulfonic acid chain extender are vacuum dried and dehydrated, and then added together with diisocyanate into a three-necked flask. The mixture is stirred and reacted at 70~90℃ for 1~3 h to obtain the prepolymer. Step 3: At 70~90℃, add trimethylolpropane to the prepolymer and crosslink it for 1~2 h. Then add 1,4-butanediol and extend the chain for 1~2 h. Then cool naturally to room temperature. Under high-speed stirring, add deionized water and emulsify for 30~60 min to obtain sulfonic acid type anionic waterborne polyurethane fixing agent.

2. The sulfonic acid-type anionic waterborne polyurethane fixing agent according to claim 1, characterized in that, The diol is at least one of polyethylene glycol, polytetrahydrofuran ether diol, polycaprolactone, and polypropylene glycol, and the molecular weight of the diol is 2000.

3. The sulfonic acid-based anionic waterborne polyurethane fixing agent according to claim 1, characterized in that, The sulfonic acid chain extender is a sulfonic acid type polyester polyol, sodium diamine sulfonate, or dihydroxypropanesulfonic acid amine.

4. The sulfonic acid-based anionic waterborne polyurethane fixing agent according to claim 3, characterized in that, The sulfonic acid type polyester polyol is a small molecule sulfonate diol BY-3306 or sulfonate polyester polyol BY-3305 produced by Beijing Baiyuan Chemical.

5. The sulfonic acid-type anionic waterborne polyurethane fixing agent according to claim 1, characterized in that, The diisocyanate is isophorone diisocyanate or hexamethylene diisocyanate.

6. The sulfonic acid-type anionic waterborne polyurethane fixing agent according to claim 1, characterized in that, The high-speed stirring in step 3 uses a rotation speed of 800~1000 r / min.

7. A sulfonic acid-based anionic aqueous polyurethane fixing agent prepared by the method according to any one of claims 1 to 6.

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