Multifunctional resin microspheres, preparation method and application thereof

Abstract

The application discloses a multifunctional resin microsphere and a preparation method and application thereof. In the field of functionalization of regenerated cellulose fiber blending spinning, in view of the problems of high raw material cost, complex synthesis process, poor dispersibility, low process adaptability and the like of functional additives, the application takes cheap and readily available melamine, amino-containing organic acid, hindered amine and aldehyde compound as raw materials, and under the condition of not adding a surfactant, a series of resin microspheres with controllable particle size and regular morphology are conveniently and efficiently synthesized by one-pot method. The microspheres are excellent in acid and alkali resistance, solvent resistance and heat resistance, and have high Zeta potential in a wide pH range, so that the dispersion stability of the microspheres in water is outstanding. In the process of spinning of regenerated cellulose fiber, the microspheres have good dispersibility and are not prone to agglomeration, and are especially suitable for lyocell spinning process. The melamine resin skeleton and the organic acid group cooperated with the hindered amine structure simultaneously endow the fiber with functions such as antibacterial property, flame retardancy and odor removal.

Description

Technical Field

[0001] This invention relates to the field of functional regenerated cellulose fiber technology, specifically to a multifunctional resin microsphere, its preparation method, and its application. Background Technology

[0002] In recent years, the regenerated cellulose fiber industry, represented by viscose and lyocell, has achieved significant industrial expansion, with global production continuing to climb. At the same time, market competition has intensified, and product homogenization has become prominent. Simply relying on scale and cost advantages is no longer sufficient to build sustainable competitiveness. Developing differentiated functional fibers (such as antibacterial, flame-retardant, and deodorizing fibers) to increase product added value is an effective way to enhance their competitiveness in the market. Blending spinning technology, by uniformly mixing functional auxiliaries into the spinning solution before spinning, has high compatibility with existing industrial spinning production lines and is the mainstream method for preparing functional fibers. However, blend spinning technology has extremely high requirements for functional auxiliaries, which usually need to meet the following stringent requirements: (1) Particle size reaches the micro-nano level to avoid clogging the spinneret and affecting fiber formation; (2) Stable structure to resist chemical erosion of spinning solution and coagulation bath and maintain functional integrity; (3) High dispersibility to be uniformly dispersed in spinning solution to ensure fiber structure uniformity and mechanical strength; (4) Multifunctional integration, a single auxiliary agent needs to have composite functions such as antibacterial, flame retardant and deodorizing to avoid compatibility problems caused by the addition of multiple components; (5) For the Lyocell process with higher spinning requirements, it is necessary not to introduce additional impurities, contaminate the spinning system and coagulation bath, and affect solvent recovery.

[0003] Currently, numerous functional additives for fibers are widely used. Related patents, such as CN 118007254 A, disclose a method for preparing viscose fibers with mosquito-repellent, insect-repellent, and antibacterial functions. This involves repeatedly dispersing and milling a polydopamine-based camphor oil-montmorillonite inclusion complex to obtain a suspension, which is then added to a viscose spinning solution and mixed evenly before spinning into fibers. CN119615401A discloses a method for preparing viscose fibers with flame-retardant and antibacterial functions. This method involves sequentially adding a phosphorus-based flame retardant, a dispersant, and graphene oxide to alkaline deionized water, then dispersing the mixture in a ball mill at 1500-3000 r / min for 3-6 hours to obtain a dispersion, which is then added to a viscose spinning solution and spun into fibers. Although milling and other methods can achieve micro- and nano-sized additives to meet processing requirements, this process is inefficient and energy-intensive. Furthermore, multifunctionality requires multiple components, which can easily lead to compatibility issues. For the more demanding lyocell spinning process, the use of dispersants and other auxiliaries affects the recovery of NMMO, limiting its application in the lyocell fiber field. Thus, while functional auxiliaries have made some progress, they generally suffer from complex processes, insufficient dispersibility, strong dependence on surfactants, and poor stability, leading to significant challenges in their industrial production and market promotion. Therefore, developing a series of highly dispersible functional auxiliaries suitable for regenerated cellulose fibers using simple and efficient synthetic routes based on inexpensive and readily available raw materials, enabling their industrialization and meeting the multifunctional needs of various fields, has become a key issue urgently needing breakthroughs in this field. Summary of the Invention

[0004] The purpose of this invention is to address the problems of insufficient dispersibility of functional auxiliaries in the blending and spinning of regenerated cellulose fibers and the excessive reliance on surfactants to contaminate the spinning system, by providing a multifunctional resin microsphere and its preparation method. This microsphere uses melamine resin microspheres as a rigid framework, and through the condensation reaction between amino groups, hindered amines and organic acid groups are introduced, significantly improving surface hydrophilicity and self-dispersibility, and synergistically achieving antibacterial, flame-retardant, and deodorizing functions through the hindered amine structure.

[0005] To achieve the above objectives, the present invention relates to a multifunctional resin microsphere with the structure shown below:

[0006]

[0007] The preparation method of the multifunctional resin microspheres includes the following steps:

[0008] Step 1: At 40-80℃ and pH=8-12, melamine, amino-containing organic acids, hindered amines and aldehyde compounds are dissolved in deionized water and stirred until the solution is clear to form a prepolymer.

[0009] Step 2: Adjust the pH of the system to 4-6, raise the temperature to 60-100℃ to carry out acid polymerization for 1-4 hours, and obtain white microspheres after separation, washing with water and drying.

[0010] The particle size of the multifunctional resin microspheres is 0.2-2.0 μm.

[0011] The melamine concentration is 10-100 g / L, the molar ratio of melamine to amino-containing organic acid is 1:0.02-1:0.2, the molar ratio of melamine to hindered amine is 1:0.05-1:0.25, and the molar ratio of the total amino equivalent of melamine, amino-containing organic acid and hindered amine to formaldehyde in aldehyde compounds is 1:0.75-1:1.5.

[0012] The amino-containing organic acid is one of p-aminobenzoic acid, m-aminobenzoic acid, p-aminophenylacetic acid, m-aminophenylacetic acid, p-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, or 2,4-diaminobenzenesulfonic acid.

[0013] The hindered amine is one of 2,2,6,6-tetramethyl-4-piperidinamine or N-butyl-2,2,6,6-tetramethyl-4-piperidinamine.

[0014] The aldehyde compound is a compound containing formaldehyde or a compound that can produce formaldehyde under the reaction conditions in step 1, including but not limited to formaldehyde, paraformaldehyde, or hexamethylenetetramine.

[0015] The application of the multifunctional resin microspheres described above as antibacterial agents, flame retardants, and deodorants, especially as functional additives in multifunctional regenerated cellulose fibers, can endow regenerated cellulose fibers with multiple functions. Specifically, the multifunctional resin microspheres are directly added to water and dispersed to obtain a slurry. The slurry is then mixed with a spinning solution, and multifunctional regenerated cellulose fibers are prepared by spinning. The mass percentage of methyl cellulose in the spinning solution is 8-10%, and the mass percentage of methyl cellulose in the multifunctional resin microspheres is 1-25%.

[0016] In the traditional reaction process, melamine reacts with formaldehyde to form resin. In this invention, hindered amines are added to the reaction process and incorporated into the resin structure to improve the antibacterial and flame retardant properties of the material. At the same time, amino-containing organic acids are incorporated into the resin structure to adjust the size and dispersion performance of the resin microspheres.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. Simplified process and low cost: Microspheres are synthesized from bulk chemicals such as melamine, 2,2,6,6-tetramethyl-4-piperidinamine, and p-aminobenzenesulfonic acid in an aqueous system through a simple reaction. No high temperature, high pressure or complex catalysts are required. The process is simple, easy to operate, has high yield and low cost.

[0019] 2. High dispersibility: The presence of amino organic acids (such as sulfonic acid groups) endows the microspheres with strong hydrophilicity and electrostatic repulsion, enabling in-situ uniform dispersion in the regenerated cellulose spinning solution. No external dispersant is required, and the microspheres can be directly and uniformly dispersed in the spinning solution without grinding. This effectively avoids agglomeration problems and prevents spinneret clogging. At the same time, it does not introduce additional impurities that affect the recycling of the spinning system.

[0020] 3. Multifunctional synergistic effect: Antibacterial properties: Hindered amines undergo hypochlorite halogenation to form an N-Cl structure, releasing active Cl... + Highly effective sterilization; flame retardancy: hindered amines capture free radicals to terminate chain reactions, amino resins have a high nitrogen content, and sulfur (from sulfonic acid groups) and nitrogen synergistically enhance flame retardancy efficiency; deodorization: the high specific surface area and porous structure of amino resin microspheres physically adsorb malodor molecules, and organic acids neutralize alkaline malodor molecules (such as ammonia, amines, etc.), while the secondary amine groups of hindered amines neutralize acidic malodor molecules (such as hydrogen sulfide, thiols, and short-chain fatty acids, etc.), achieving broad-spectrum deodorization.

[0021] 4. Structural stability: The microspheres have excellent acid and alkali resistance, solvent resistance and high temperature resistance, making them suitable for complex processing environments. They are structurally stable in spinning coagulation baths (H2SO4 / Na2SO4 or NMMO), and the functional components do not dissolve. The 0.2-2.0μm microsphere size matches the fiber diameter, and after blending and spinning, they are uniformly embedded inside the fiber, giving it lasting function without compromising strength. Attached Figure Description

[0022] Figure 1 The images shown are scanning electron microscope (SEM) images of the multifunctional resin microspheres from Examples 1, 4, 6, and 8, respectively. The images show that the microspheres are monodisperse and uniform in size.

[0023] Figure 2 a and b are particle size distribution diagrams of the multifunctional resin microspheres in Examples 4 and 8. It can be seen that the microsphere particle size distribution is narrow, proving that the microspheres are uniform in size. The particle size ranges of the multifunctional resin microspheres prepared in Examples 4 and 8 are 0.2-1.4 μm and 0.6-1.9 μm, respectively.

[0024] Figure 3 The image shows the solid-state NMR spectrum of the multifunctional resin microspheres from Example 1, proving the successful synthesis of the multifunctional resin microspheres.

[0025] Figure 4 The H3 / IV type adsorption isotherm of the multifunctional resin microspheres prepared in Example 7 shows that micropores and mesopores coexist, and the resin microspheres have good adsorption performance. The corresponding pore size distribution exhibits a multi-peak characteristic spanning from micropores to macropores, confirming the hierarchical porosity of the multifunctional resin microspheres.

[0026] Figure 5The image shows the Zeta potential of the multifunctional resin microspheres prepared in Example 3 at different pH values. The multifunctional resin microspheres have higher potentials under acidic and alkaline conditions, which confirms that they are not prone to aggregation and have good dispersibility.

[0027] Figure 6 The diagram shows the Zeta potential of Comparative Example 1 at different pH values. Comparative Example 1 has a lower potential under acidic and alkaline conditions. Detailed Implementation

[0028] The following embodiments are provided to further illustrate the present invention. It should be noted that the following embodiments should not be construed as limiting the scope of protection of the present invention. If those skilled in the art make some non-essential improvements and adjustments to the present invention based on the above description, they shall still fall within the scope of protection of the present invention.

[0029] Example 1

[0030] Melamine, p-aminobenzenesulfonic acid, 2,2,6,6-tetramethyl-4-piperidinamine, and paraformaldehyde were reacted at 50°C and pH 8.5 until the solution became clear, yielding a prepolymer solution.

[0031] The temperature was raised to 100℃, the pH was set to 6, and the reaction time was 1 hour to obtain a white solid. After separating the solid, it was dried to obtain multifunctional resin microspheres.

[0032] The melamine concentration was 30 g / L, the molar ratio of melamine to p-aminobenzenesulfonic acid was 1:0.02, the molar ratio of melamine to 2,2,6,6-tetramethyl-4-piperidinamine was 1:0.05, and the molar ratio of the amino equivalent of melamine, p-aminobenzenesulfonic acid, and 2,2,6,6-tetramethyl-4-piperidinamine to the formaldehyde equivalent in paraformaldehyde was 1:0.75.

[0033] Example 2

[0034] Melamine, p-aminobenzoic acid, 2,2,6,6-tetramethyl-4-piperidinamine, and paraformaldehyde were reacted at 80°C and pH 12 until the solution became clear, yielding a prepolymer solution.

[0035] The temperature was raised to 80℃, the pH was set to 4, and the reaction time was 4 hours to obtain a white solid. After separating the solid, it was dried to obtain multifunctional resin microspheres.

[0036] The melamine concentration was 100 g / L, and the molar ratio of melamine to p-aminobenzoic acid was 1:0.2.

[0037] The molar ratio of melamine to 2,2,6,6-tetramethyl-4-piperidinamine is 1:0.2, and the molar ratio of the amino equivalent of melamine, p-aminobenzoic acid, and 2,2,6,6-tetramethyl-4-piperidinamine to the formaldehyde equivalent in paraformaldehyde is 1:1.5.

[0038] Example 3

[0039] Melamine, p-aminophenylacetic acid, N-butyl-2,2,6,6-tetramethyl-4-piperidinamine, and formaldehyde were reacted at 60°C and pH 10 until the solution became clear, yielding a prepolymer solution.

[0040] The temperature was raised to 90℃, the pH was set to 5, and the reaction time was 3 hours to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres.

[0041] The melamine concentration was 50 g / L, the molar ratio of melamine to p-aminophenylacetic acid was 1:0.1, the molar ratio of melamine to N-butyl-2,2,6,6-tetramethyl-4-piperidinamine was 1:0.25, and the molar ratio of the amino equivalent of melamine, p-aminophenylacetic acid, and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine to formaldehyde was 1:1.25.

[0042] Example 4

[0043] Melamine, m-aminobenzenesulfonic acid, 2,2,6,6-tetramethyl-4-piperidinamine, and paraformaldehyde were reacted at 40°C and pH 9 until the solution became clear, yielding a prepolymer solution.

[0044] The temperature was raised to 85℃, the pH was set to 5.5, and the reaction time was 2.5 h to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres.

[0045] The melamine concentration was 70 g / L, the molar ratio of melamine to m-aminobenzenesulfonic acid was 1:0.15, the molar ratio of melamine to 2,2,6,6-tetramethyl-4-piperidineamine was 1:0.15, and the molar ratio of the amino equivalent of melamine, m-aminobenzenesulfonic acid, and 2,2,6,6-tetramethyl-4-piperidineamine to the formaldehyde equivalent in paraformaldehyde was 1:1.5.

[0046] Example 5

[0047] Melamine, m-aminobenzoic acid, N-butyl-2,2,6,6-tetramethyl-4-piperidinamine, and hexamethylenetetramine were reacted at 70°C and pH 11 until the solution became clear, yielding a prepolymer solution.

[0048] The temperature was raised to 95℃, the pH was set to 4.5, and the reaction time was 3.5 h to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres.

[0049] The melamine concentration was 20 g / L, the molar ratio of melamine to m-aminobenzoic acid was 1:0.08, the molar ratio of melamine to N-butyl-2,2,6,6-tetramethyl-4-piperidinamine was 1:0.08, and the molar ratio of the amino equivalent of melamine, m-aminobenzoic acid, and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine to the formaldehyde equivalent in hexamethylenetetramine was 1:0.75.

[0050] Example 6

[0051] Melamine, m-aminophenylacetic acid, 2,2,6,6-tetramethyl-4-piperidinamine, and paraformaldehyde were reacted at 55°C and pH 8.2 until the solution became clear, yielding a prepolymer solution.

[0052] The temperature was raised to 88℃, the pH was set to 5.8, and the reaction time was 1.5 h to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres.

[0053] The melamine concentration was 80 g / L, the molar ratio of melamine to m-aminophenylacetic acid was 1:0.12, the molar ratio of melamine to 2,2,6,6-tetramethyl-4-piperidinamine was 1:0.18, and the molar ratio of the amino equivalent of melamine, m-aminophenylacetic acid, and 2,2,6,6-tetramethyl-4-piperidinamine to the formaldehyde equivalent in paraformaldehyde was 1:1.2.

[0054] Example 7

[0055] Melamine, p-aminobenzoic acid, N-butyl-2,2,6,6-tetramethyl-4-piperidinamine, and formaldehyde were reacted at 45°C and pH 8.8 until the solution became clear, yielding a prepolymer solution.

[0056] The temperature was raised to 82℃, the pH was set to 4.8, and the reaction time was 2 hours to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres.

[0057] The melamine concentration was 15 g / L, the molar ratio of melamine to p-aminobenzoic acid was 1:0.06, the molar ratio of melamine to N-butyl-2,2,6,6-tetramethyl-4-piperidinamine was 1:0.06, and the molar ratio of the amino equivalent of melamine, p-aminobenzoic acid, and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine to formaldehyde was 1:0.9.

[0058] Example 8

[0059] Melamine, m-aminobenzenesulfonic acid, 2,2,6,6-tetramethyl-4-piperidinamine, and hexamethylenetetramine were reacted at 75°C and pH 10.5 until the solution became clear, yielding a prepolymer solution.

[0060] The temperature was raised to 98℃, the pH was set to 5.2, and the reaction time was 4 hours to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres.

[0061] The melamine concentration was 90 g / L, the molar ratio of melamine to m-aminobenzenesulfonic acid was 1:0.19, the molar ratio of melamine to 2,2,6,6-tetramethyl-4-piperidineamine was 1:0.07, and the molar ratio of the amino equivalent of melamine, m-aminobenzenesulfonic acid, and 2,2,6,6-tetramethyl-4-piperidineamine to the formaldehyde equivalent in hexamethylenetetramine was 1:1.2.

[0062] Example 9

[0063] Melamine, p-aminophenylacetic acid, 2,2,6,6-tetramethyl-4-piperidinamine, and paraformaldehyde were reacted at 65°C and pH 9.5 until the solution became clear, yielding a prepolymer solution.

[0064] The temperature was raised to 92℃, the pH was set to 5.5, and the reaction time was 2.8 h to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres.

[0065] The melamine concentration was 40 g / L, the molar ratio of melamine to p-aminophenylacetic acid was 1:0.09, the molar ratio of melamine to 2,2,6,6-tetramethyl-4-piperidinamine was 1:0.09, and the molar ratio of the amino equivalent of melamine, p-aminophenylacetic acid, and 2,2,6,6-tetramethyl-4-piperidinamine to the formaldehyde equivalent in paraformaldehyde was 1:1.

[0066] Example 10

[0067] Melamine, 2,4-diaminobenzenesulfonic acid, N-butyl-2,2,6,6-tetramethyl-4-piperidinamine and paraformaldehyde were reacted at 58°C and pH 8.3 until the solution became clear, thus obtaining a prepolymer solution.

[0068] The temperature was raised to 87℃, the pH was set to 4.3, and the reaction time was 3.2 h to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres.

[0069] The melamine concentration was 60 g / L, the molar ratio of melamine to 2,4-diaminobenzenesulfonic acid was 1:0.16, the molar ratio of melamine to N-butyl-2,2,6,6-tetramethyl-4-piperidinamine was 1:0.14, and the molar ratio of the amino equivalent of melamine, 2,4-diaminobenzenesulfonic acid, and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine to the formaldehyde equivalent in paraformaldehyde was 1:1.1.

[0070] Comparative Example 1:

[0071] Melamine, N-butyl-2,2,6,6-tetramethyl-4-piperidinamine, and formaldehyde were reacted at 60°C and pH 10 until the solution became clear, yielding a prepolymer solution.

[0072] The temperature was raised to 90℃, the pH was set to 5, and the reaction time was 3 hours to obtain a white solid. After separation and drying, the solid was obtained as multifunctional resin microspheres. The particle size range of these multifunctional resin microspheres was 2.1-6.0 μm, but the microspheres were uneven in size and shape, requiring the addition of surfactants to adjust their uniformity.

[0073] The melamine concentration was 50 g / L, the molar ratio of melamine to N-butyl-2,2,6,6-tetramethyl-4-piperidinamine was 1:0.25, and the molar ratio of the amino equivalent of melamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine to formaldehyde was 1:1.25.

[0074] Application Example 1: Flame-retardant and antibacterial regenerated cellulose fibers were prepared using multifunctional resin microspheres from Example 1.

[0075] Under normal conditions, multifunctional resin microspheres are mixed with spinning solution, defoamed, shaped by spinning process, and then washed, bleached with chlorine, dried and oiled to obtain flame-retardant and antibacterial regenerated cellulose fiber. The multifunctional resin microspheres account for 15% of the mass of cellulose fiber.

[0076] Application Example 2: Flame-retardant and antibacterial regenerated cellulose fibers were prepared using multifunctional resin microspheres from Example 4.

[0077] Under normal conditions, multifunctional resin microspheres are mixed with spinning solution, defoamed, shaped by spinning process, and then washed, bleached with chlorine, dried and oiled to obtain flame-retardant and antibacterial regenerated cellulose fiber. The multifunctional resin microspheres account for 20% of the mass of cellulose fiber.

[0078] Application Example 3: Flame-retardant and antibacterial regenerated cellulose fibers were prepared using multifunctional resin microspheres from Example 7.

[0079] Under normal conditions, multifunctional resin microspheres are mixed with spinning solution, defoamed, shaped by spinning process, and then washed, bleached with chlorine, dried and oiled to obtain flame-retardant and antibacterial regenerated cellulose fiber. The multifunctional resin microspheres account for 25% of the mass of cellulose fiber.

[0080] The antibacterial properties (S. aureus, E. coli, and C. albicans) of the fibers obtained from Examples 1-3 of GB / T 20944.3-2008 "Evaluation of Antibacterial Properties of Textiles" were tested. The flame retardant properties of the fibers obtained from Examples 1-3 were tested using the Oxygen Index Method of FZ / T 50016-2023 "Test Method for Burning Performance of Chemical Fibers" standard, and the Limiting Oxygen Index (LOI) was obtained, as shown in Table 1. Table 1 lists the antibacterial properties and Limiting Oxygen Index (LOI) of the fibers obtained from Examples 1-3 against S. aureus, E. coli, and C. albicans. It can be seen that the antibacterial fibers involved all achieved an inhibition rate of 99.99%, demonstrating outstanding antibacterial performance, and all had LOIs greater than 28%, indicating good flame retardant effects.

[0081] Table 1

[0082]

Claims

1. A method for preparing multifunctional resin microspheres, characterized in that, Includes the following steps: Step 1: Melamine, amino-containing organic acid, hindered amine, and aldehyde compound are continuously stirred at pH 8-12 and temperature 40-80 °C until the solution becomes clear, yielding a prepolymer solution; the molar ratio of melamine to amino-containing organic acid is 1:0.02-1:0.2, and the molar ratio of melamine to hindered amine is 1:0.05-1:0.25; Step 2: Adjust the pH of the prepolymer solution to acidic, and stir continuously at pH 4-6 and temperature 60-100 °C for 1-4 hours. After separating the solid, dry it to obtain multifunctional resin microspheres; the molar ratio of amino equivalent of melamine, amino-containing organic acid, hindered amine to formaldehyde in aldehyde compound is 1:0.75-1:1.5; the melamine concentration does not exceed 100 g / L; The amino-containing organic acid is one of p-aminobenzoic acid, m-aminobenzoic acid, p-aminophenylacetic acid, m-aminophenylacetic acid, p-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, or 2,4-diaminobenzenesulfonic acid; the hindered amine is one of 2,2,6,6-tetramethyl-4-piperidinamine or N-butyl-2,2,6,6-tetramethyl-4-piperidinamine; and the aldehyde compound is one of formaldehyde, paraformaldehyde, or hexamethylenetetramine.

2. The multifunctional resin microspheres prepared by the method of claim 1.

3. The application of the multifunctional resin microspheres as a functional additive in multifunctional regenerated cellulose fibers according to claim 2.

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