A fluorescent whitening agent anti-migration stabilizing adjuvant and a preparation method thereof

Abstract

This invention belongs to the field of polymer material additives, and provides a fluorescent whitening agent anti-migration stabilizing excipient and its preparation method. The method involves intercalating 4,4'-bis(2-sulfonate sodium styryl)biphenyl into a zinc-aluminum layered double hydroxide, and then surface-coating it with ethanolamine-modified polypropylene grafted with maleic anhydride compatible components. This is followed by melt granulation with a polypropylene carrier resin, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol. This achieves low migration, high retention, and stable dispersion of the fluorescent whitening agent, solving the problems of easy migration, insufficient thermo-photoaging stability, and difficulty in balancing processing window and toughness in polypropylene systems. This method is suitable for the industrial preparation and application of polypropylene whitening modified materials.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification and plastic additives, specifically to a fluorescent whitening agent anti-migration stabilizing excipient and its preparation method. Background Technology

[0002] Polypropylene (PP) materials are widely used in various applications, including appliance exterior components, daily necessities, packaging materials, automotive interiors, and fiber products, due to their lightweight, chemical resistance, high molding efficiency, and moderate cost. In these applications, materials typically require a stable, clean, and consistent white appearance. Therefore, fluorescent whitening components must not only be uniformly dispersed within the continuous polypropylene phase but also maintain high stability and interfacial consistency during melt processing, storage, transportation, and long-term service. This prevents issues such as blooming, loss of whiteness, surface contamination, and appearance fluctuations caused by migration, precipitation, localized enrichment, or distribution imbalance. Simultaneously, the introduction of inorganic confinement units, interfacial regulation units, and aging stabilization units into a polypropylene system can affect the material's flow behavior, compatibility, stress transfer, and reprocessing adaptability. Therefore, relevant formulations must also consider melt flowability, extrusion granulation adaptability, dispersion uniformity, and product toughness. Only by establishing a synergistic relationship between whitening maintenance, anti-migration stability, processing window, and mechanical balance can the comprehensive needs of continuous manufacturing and end-use be met.

[0003] Existing technologies have explored aspects such as precipitation control, photoaging resistance, and stabilization of fluorescent whitening components in polypropylene materials. For example, Chinese patent CN111087695A discloses a high-performance, low-cost polypropylene composite material with anti-precipitation and scratch resistance, and its preparation method. This method reduces the risk of light stabilizer precipitation by introducing components such as fumed silica and organic light stabilizers into polypropylene. However, based on its disclosure, this approach focuses on inhibiting the precipitation of conventional organic light stabilizers and does not establish a targeted design for the interlayer confinement and interface fixation of specific fluorescent whitening agents. Another example is Chinese patent CN108517718A, which discloses a method for preparing a layered bimetallic hydroxide-based multifunctional paper surface sizing agent, combining layered bimetallic hydroxides, polymers, and fluorescent whitening agents. However, based on its disclosed target and process route, this approach belongs to water-based paper surface treatment, which differs significantly from polypropylene melt-blending systems in terms of continuous phase polarity, processing environment, and interfacial interaction mechanisms. Therefore, existing technologies still have significant shortcomings in simultaneously achieving high fluorescent whitening agent fixation efficiency, anti-migration stability, and maintaining processing fluidity and toughness. Summary of the Invention

[0004] The purpose of this invention is to provide a fluorescent whitening agent anti-migration stabilizing excipient and its preparation method, which solves the problem of difficulty in balancing low migration and long-term stability with processing fluidity and toughness in existing polypropylene whitening systems.

[0005] This invention confines 4,4'-bis(2-sulfonate styryl)biphenyl within the interlayer of a zinc-aluminum layered double hydroxide, constructs an outer interface with ethanolamine-modified polypropylene grafted with maleic anhydride compatible components, and combines the synergistic stabilizing effects of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol, thereby achieving a balance between fixation, compatibility, stability, and processing performance, thus taking into account migration inhibition, aging retention, and melt processing adaptability.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A fluorescent whitening agent anti-migration stabilizing excipient, comprising the following components, each component in wt%, and the total content of all components being 100 wt%:

[0008] (1) 21-60wt% of surface-coated anti-migration stabilizing intermediates;

[0009] (2) 36-75wt% polypropylene carrier resin;

[0010] (3) 0.10-2.00 wt% of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate;

[0011] (4) 0.10-2.00 wt% of 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol;

[0012] The surface-coated anti-migration stabilizing intermediate includes a fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate, and an ethanolamine-modified polypropylene grafted with maleic anhydride compatible component coated on the surface of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate.

[0013] The fluorescent whitening agent is 4,4'-bis(2-sodium styryl sulfonate)biphenyl;

[0014] The interlayer spacing of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is 0.90-1.30 nm, and the coating amount of the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component is 3-15 wt% of the total mass of the surface-coated anti-migration stable intermediate.

[0015] Furthermore, the ethanolamine-modified polypropylene grafted with maleic anhydride compatibility component is prepared through the following steps:

[0016] A1. Add polypropylene grafted with maleic anhydride and xylene to a reaction vessel. The mass ratio of polypropylene grafted with maleic anhydride to xylene is 1:4 to 1:15. Heat the mixture to 110-140℃ to dissolve it.

[0017] A2. Add ethanolamine, and the mass ratio of maleic anhydride grafted onto polypropylene to ethanolamine is 100:1 to 100:8. React at 90-130℃ for 1-4 hours.

[0018] A3. Terminate the reaction when the residual anhydride group content is not higher than 0.5 wt%.

[0019] A4. After cooling the reaction solution, allow the product to precipitate and filter it. Then, dry it at 60-90℃ for 4-12 hours to obtain the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component.

[0020] Furthermore, the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is prepared through the following steps:

[0021] B1. Dissolve zinc nitrate hexahydrate and aluminum nitrate nonahydrate in deionized water, controlling the molar ratio of zinc to aluminum to be 2.0-4.0:1, to obtain a metal salt solution;

[0022] B2. Prepare an alkaline solution by mixing sodium hydroxide and sodium carbonate, and co-precipitate the metal salt solution with the alkaline solution at 60-80℃, controlling the pH to 9-11, and aging for 4-8 hours;

[0023] B3. The obtained precipitate was washed until the pH was 7-8 and dried at 60-80℃ for 8-12 h to obtain the zinc-aluminum layered double hydroxide precursor;

[0024] B4. Disperse the zinc-aluminum layered double hydroxide precursor in an aqueous solution containing the fluorescent whitening agent, control the pH to 6-8, and carry out ion exchange at 60-80℃ for 8-16 hours;

[0025] B5. Wash and dry to obtain the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate with an interlayer spacing of 0.90-1.30 nm.

[0026] Furthermore, the surface-coated anti-migration stabilizing intermediate is prepared through the following steps:

[0027] C1. The fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is dispersed in a mixed medium of ethanol and water, wherein the volume ratio of ethanol to water is 1:1 to 1:4.

[0028] C2. Add ethanolamine-modified polypropylene grafted with maleic anhydride compatible component, wherein the mass ratio of the amount of ethanolamine-modified polypropylene grafted with maleic anhydride compatible component to the mass ratio of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is 1:3 to 1:20.

[0029] C3. Stir at 40-80℃ for 1-4 hours;

[0030] C4. Filter and dry at 50-80℃ for 4-10h to obtain the surface-coated anti-migration stable intermediate, wherein the coating amount of the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component is 3-15wt% of the total mass of the surface-coated anti-migration stable intermediate.

[0031] Furthermore, at least one of the following technical features is true:

[0032] In the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate, the content of the fluorescent whitening agent is 5-25 wt%.

[0033] The actual molar ratio of zinc to aluminum in the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is 2.2-3.5:1;

[0034] The median particle size D50 of the surface-coated anti-migration stabilizing intermediate is 0.1-2.0 μm.

[0035] Furthermore, at least one of the following technical features is true:

[0036] The melt flow rate of the polypropylene carrier resin is 2-30 g / 10 min.

[0037] The mass ratio of the bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate to the 2-(2H-benzotriazol-2-yl)-4,6-ditert-pentylphenol is 0.5-2.0:1.

[0038] As a concept of the present invention, the present invention uses 4,4'-bis(2-sulfonate styrene)biphenyl intercalated zinc-aluminum layered double hydroxide and designs for ethanolamine-modified polypropylene grafted with maleic anhydride compatible components for surface coating. This is mainly used to enhance the anti-migration stability, heat and light aging retention performance, and dispersion uniformity of the polypropylene system against fluorescent whitening agents. The interlayer structure of zinc-aluminum layered double hydroxides can confine and support the fluorescent whitening agent, reducing its tendency to migrate freely in the nonpolar continuous phase. The compatible interface after surface coating helps to reduce the interfacial mismatch between the inorganic phase and polypropylene, improves the dispersion of intermediates in the polypropylene carrier resin, and reduces the risk of agglomeration, stress concentration, and embrittlement caused by local enrichment. At the same time, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol provide stabilizing support from the perspectives of free radical inhibition and ultraviolet absorption, respectively, so that the fixation of the fluorescent whitening agent, interfacial compatibility, and aging protection can be synergistically achieved. Thus, long-term stability and processing adaptability can be achieved without relying on the constraint of a single high addition amount.

[0039] This invention also discloses a method for preparing an anti-migration stabilizing excipient for fluorescent whitening agents, comprising the following steps:

[0040] S1. Provides a prepared surface-coated anti-migration stabilizing intermediate;

[0041] S2. The surface-coated anti-migration stabilizing intermediate, polypropylene carrier resin, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol provided in step S1 are mixed, wherein the content of each component is in wt%, the content of the surface-coated anti-migration stabilizing intermediate is 21-60 wt%, the content of the polypropylene carrier resin is 36-75 wt%, the content of the bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate is 0.10-2.00 wt%, the content of the 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol is 0.10-2.00 wt%, and the total content of each component is 100 wt%.

[0042] S3. The mixture obtained in step S2 is melt-blended and granulated in a twin-screw extruder at 160-210℃ to obtain a fluorescent whitening agent anti-migration stabilizing excipient.

[0043] Furthermore, at least one of the following process characteristics is true:

[0044] The premixing time for each component in step S2 is 3-20 min;

[0045] In step S3, the screw speed is 150-300 r / min, and the residence time is 45-120 s;

[0046] In step S3, the temperatures of each zone of the extruder from the feeding end to the die head are 160-180℃, 170-190℃, 180-200℃ and 190-210℃ respectively.

[0047] The granulation method after step S3 is water-stretching granulation or underwater pelletizing.

[0048] Furthermore, before step S2, the surface-coated anti-migration stabilizing intermediate provided in step S1 is pre-dried at 80-100°C for 2-8 hours.

[0049] Furthermore, the fluorescent whitening agent anti-migration stabilizing excipient obtained in step S3 may possess at least one of the following product characteristics, but is not required to satisfy all of them simultaneously:

[0050] The total content of 4,4'-bis(2-sulfonate styryl)biphenyl is 0.5-10 wt%;

[0051] Under conditions of 70℃ and 168h, the migration loss rate of 4,4'-bis(2-sulfonate styryl)biphenyl is no higher than 8%.

[0052] Furthermore, the interlayer spacing of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate was measured by X-ray diffraction and calculated using the (003) crystal plane diffraction peak.

[0053] Furthermore, the coating amount of the ethanolamine-modified polypropylene grafted with maleic anhydride compatible components is determined by thermogravimetric difference method or extraction weight loss method, with reference to the uncoated fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate.

[0054] Furthermore, the content of the residual anhydride groups was determined by chemical titration.

[0055] Furthermore, the median particle size D50 of the surface-coated anti-migration stabilizing intermediate was measured by laser particle size analysis.

[0056] Furthermore, the melt flow rate of the polypropylene carrier resin was measured at 230°C and 2.16 kg.

[0057] Furthermore, step A1 is carried out in a reaction vessel equipped with a stirring device and a condenser.

[0058] Furthermore, in step A4, the product is precipitated by adding an alcohol precipitant, then filtered and dried under vacuum conditions.

[0059] Furthermore, the total metal ion concentration of the metal salt solution in step B1 is 0.05-1.00 mol / L.

[0060] Furthermore, in step B2, the concentration of sodium hydroxide in the alkaline solution is 0.5-3.0 mol / L, the concentration of sodium carbonate is 0.05-1.0 mol / L, and the pH is controlled by dropwise addition.

[0061] Furthermore, before step B4, the zinc-aluminum layered double hydroxide precursor is decarbonated before ion exchange.

[0062] Furthermore, in step B4, the concentration of the aqueous solution of the fluorescent whitening agent is 1-50 g / L, and the liquid-to-solid ratio of the aqueous solution of the fluorescent whitening agent to the zinc-aluminum layered double hydroxide precursor is 5-30 mL / g.

[0063] Furthermore, the dispersion in step C1 is carried out by mechanical stirring or ultrasonic dispersion, and the mass-to-volume ratio of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate in the ethanol and water mixture is 0.02-0.20 g / mL.

[0064] Furthermore, in step C2, the ethanolamine-modified polypropylene grafted with maleic anhydride compatibility component is first dissolved or uniformly dispersed before being added.

[0065] Furthermore, the twin-screw extruder described in step S3 has a length-to-diameter ratio of 30:1 to 52:1 and is equipped with a vacuum exhaust section.

[0066] Furthermore, the migration loss rate is expressed as the percentage difference in the content of 4,4'-bis(2-sulfonate styryl)biphenyl before and after aging relative to the content before aging.

[0067] Beneficial technical effects

[0068] 1. By intercalating 4,4'-bis(2-sulfonate styryl)biphenyl between zinc-aluminum layered double hydroxides and further coating the surface with ethanolamine-modified polypropylene grafted with maleic anhydride compatible components, the fixation degree of fluorescent whitening agent in the polypropylene system can be significantly improved, and the migration and precipitation tendency during processing and service can be reduced.

[0069] 2. By constructing a surface-coated, migration-resistant, and stable intermediate, a more favorable interface transition can be formed between the inorganic confined structure and the continuous polypropylene phase. This can improve the dispersion uniformity of the intermediate, reduce the risk of embrittlement caused by inorganic phase agglomeration and local stress concentration, and thus better maintain the toughness and appearance consistency of the material.

[0070] 3. The synergistic stabilizing configuration of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol can provide continuous protection for the system from the perspectives of free radical inhibition and ultraviolet absorption, which is beneficial to improving the retention ability of fluorescent whitening agents under thermal and photoaging conditions.

[0071] 4. By first preparing a surface-coated anti-migration stabilizing intermediate, and then melt-blending and granulating it with polypropylene carrier resin and stabilizing components, this invention takes into account both structural fixation and industrial processing feasibility. The process route is clear, suitable for continuous production, and conducive to improving batch stability and subsequent application compatibility. Attached Figure Description

[0072] Figure 1 The TGA DTG curves are for Example 1 and Comparative Example 8.

[0073] Figure 2 The graphs show the laser particle size distribution frequency curves for Example 1 and Comparative Example 3.

[0074] Figure 3 The cumulative distribution curves of laser particle size are shown for Example 1 and Comparative Example 3.

[0075] Figure 4 The FTIR spectra of Example 1 and Comparative Example 8 are shown.

[0076] Figure 5The graphs show the UV aging whiteness retention rates of Example 1, Comparative Example 10, and Comparative Example 5.

[0077] Figure 6 The diagram shows the migration loss rate kinetics of Example 1 and Comparative Example 10.

[0078] Figure 7 Macroscopic optical photograph of the anti-migration stabilizing excipient for the fluorescent whitening agent prepared in Example 1.

[0079] Figure 8 The image shows a scanning electron microscope (SEM) image of the anti-migration stabilizing excipient for the fluorescent whitening agent prepared in Example 1. Wherein: Figure 8 (a) is a low-magnification scanning electron microscope image; Figure 8 (b) is a medium-magnification scanning electron microscope image; Figure 8 (c,d) are high-magnification scanning electron microscope images. Detailed Implementation

[0080] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0081] Example 1

[0082] I. Preparation of Ethanolamine-Modified Polypropylene Grafted with Maleic Anhydride Compatible Component

[0083] 100g of polypropylene grafted with maleic anhydride and 1500g of xylene were added to a reaction vessel equipped with a stirrer and a condenser. The mass ratio of polypropylene grafted with maleic anhydride to xylene was 1:15. The mixture was heated to 140°C to allow for complete dissolution. 1g of ethanolamine was then added, bringing the mass ratio of polypropylene grafted with maleic anhydride to ethanolamine to 100:1. The reaction was carried out at 90°C for 1 hour. The residual anhydride group content was monitored by chemical titration. The reaction was terminated when the residual anhydride group content decreased to 0.5wt%. After cooling the reaction solution, an ethanol precipitant was added to precipitate the product, which was then filtered. The product was dried under vacuum at 60°C for 4 hours to obtain the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component of this embodiment.

[0084] II. Preparation of fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate

[0085] Zinc nitrate hexahydrate and aluminum nitrate nonahydrate were dissolved in deionized water, with the molar ratio of zinc to aluminum controlled at 2.0:1, to prepare a metal salt solution with a total metal ion concentration of 0.05 mol / L. Sodium hydroxide and sodium carbonate were prepared into an alkaline solution, with a sodium hydroxide concentration of 0.5 mol / L and a sodium carbonate concentration of 0.05 mol / L. The metal salt solution and the alkaline solution of this embodiment were co-precipitated by dropwise addition at 60°C, with the pH controlled at 9, and aged for 4 hours. The resulting precipitate was washed until the pH reached 7 and dried at 60°C for 8 hours to obtain a zinc-aluminum layered double hydroxide precursor.

[0086] The zinc-aluminum layered double hydroxide precursor of this embodiment was dispersed in an aqueous solution containing 4,4'-bis(2-sulfonated sodium styrene)biphenyl. The concentration of the 4,4'-bis(2-sulfonated sodium styrene)biphenyl aqueous solution in this embodiment was 12 g / L. The liquid-to-solid ratio of the 4,4'-bis(2-sulfonated sodium styrene)biphenyl aqueous solution to the zinc-aluminum layered double hydroxide precursor of this embodiment was 5 mL / g. The pH was controlled at 6, and ion exchange was performed at 60°C for 8 h. After washing and drying, the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was obtained. By X-ray diffraction, based on the (003) crystal plane diffraction peak, the interlayer spacing of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was 0.90 nm, the content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl was 5 wt%, and the actual molar ratio of zinc to aluminum was 2.2:1.

[0087] III. Preparation of Surface-Coated Anti-Migration Stabilizing Intermediates

[0088] The fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was dispersed in a mixed medium of ethanol and water, with a volume ratio of ethanol to water of 1:1. The mass-to-volume ratio of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate in this embodiment was 0.02 g / mL, and dispersion was performed by mechanical stirring. The ethanolamine-modified polypropylene grafted maleic anhydride compatible component of this embodiment was first uniformly dispersed and then added, with a mass ratio of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component to the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment of 1:20. The mixture was stirred at 40°C for 1 h. After filtration and drying at 50°C for 4 h, the surface-coated anti-migration stable intermediate of this embodiment was obtained. Thermogravimetric analysis showed that the coating amount of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component of this embodiment was 3 wt% of the total mass of the surface-coated anti-migration stable intermediate of this embodiment. According to laser particle size analysis, the median particle size D50 of the surface-coated anti-migration stabilizing intermediate in this embodiment is 0.1 μm.

[0089] IV. Preparation of Anti-migration Stabilizing Excipients for Fluorescent Whitening Agents

[0090] The surface-coated anti-migration stabilizing intermediate of this embodiment was pre-dried at 80°C for 2 hours. 21.00 wt% of the pre-dried surface-coated anti-migration stabilizing intermediate, 75.00 wt% of polypropylene carrier resin, 2.00 wt% of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, and 2.00 wt% of 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol were premixed for 3 minutes, with a total component content of 100 wt%. The melt flow rate of the polypropylene carrier resin in this embodiment was measured at 230°C and 2.16 kg, and was 2 g / 10 min. The mass ratio of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate to 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol in this embodiment was 1:1.

[0091] The mixture of this embodiment is melt-blended and granulated in a twin-screw extruder. The twin-screw extruder of this embodiment has a length-to-diameter ratio of 30:1, is equipped with a vacuum exhaust section, has a screw speed of 150 r / min, a residence time of 45 s, and the temperatures of each zone of the extruder from the feeding end to the die head are 160℃, 170℃, 180℃, and 190℃ respectively. Water-stretched granulation is used to obtain the anti-migration stabilizing excipient of the fluorescent whitening agent of this embodiment.

[0092] The total content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl in the anti-migration stabilizing excipient of the fluorescent whitening agent in this embodiment was determined to be 1.0 wt%. Under the conditions of 70°C and 168 h, the migration loss rate of 4,4'-bis(2-sulfonated sodium styrene)biphenyl in this embodiment was 3.2%, and the migration loss rate was expressed as the percentage difference in the content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl before and after aging relative to the content before aging.

[0093] Features of Example 1: This example employs a scheme combining a low proportion of surface-coated anti-migration stabilizing intermediates with a high proportion of polypropylene carrier resin, supplemented by a high content of light stabilizers and UV absorbers, forming a stabilization system with a high carrier ratio. Process parameters favoring basic conditions are selected during preparation, including lower reaction temperatures, shorter reaction times, and lower energy input, resulting in mild preparation conditions. The coating process uses a low coating amount design, coupled with low-energy drying conditions, to obtain fine-particle-size intermediates. Extrusion compounding utilizes a low-speed, low-temperature processing window, suitable for applications with high requirements for heat sensitivity, and particularly suitable for polypropylene products requiring consistent whiteness, low migration, and mild processing conditions.

[0094] Example 2

[0095] I. Preparation of Ethanolamine-Modified Polypropylene Grafted with Maleic Anhydride Compatible Component

[0096] 100g of polypropylene grafted with maleic anhydride and 400g of xylene were added to a reaction vessel equipped with a stirrer and a condenser. The mass ratio of polypropylene grafted with maleic anhydride to xylene was 1:4. The mixture was heated to 110°C to allow for complete dissolution. 8g of ethanolamine was then added, bringing the mass ratio of polypropylene grafted with maleic anhydride to ethanolamine to 100:8. The reaction was carried out at 130°C for 4 hours. The residual anhydride group content was monitored by chemical titration. The reaction was terminated when the residual anhydride group content decreased to 0.2wt%. After cooling the reaction solution, ethanol precipitant was added to precipitate the product, which was then filtered. The product was dried under vacuum at 90°C for 12 hours to obtain the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component of this embodiment.

[0097] II. Preparation of fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate

[0098] Zinc nitrate hexahydrate and aluminum nitrate nonahydrate were dissolved in deionized water, with the molar ratio of zinc to aluminum controlled at 4.0:1, to prepare a metal salt solution with a total metal ion concentration of 1.00 mol / L. Sodium hydroxide and sodium carbonate were prepared into an alkaline solution, with a sodium hydroxide concentration of 3.0 mol / L and a sodium carbonate concentration of 1.0 mol / L. The metal salt solution and the alkaline solution of this embodiment were co-precipitated by dropwise addition at 80°C, with the pH controlled at 11, and aged for 8 hours. The resulting precipitate was washed until the pH reached 8 and dried at 80°C for 12 hours to obtain a zinc-aluminum layered double hydroxide precursor.

[0099] After decarbonate treatment, the zinc-aluminum layered double hydroxide precursor of this embodiment was dispersed in an aqueous solution containing 4,4'-bis(2-sulfonated sodium styrene)biphenyl. The concentration of the 4,4'-bis(2-sulfonated sodium styrene)biphenyl aqueous solution in this embodiment was 50 g / L, and the liquid-to-solid ratio of the 4,4'-bis(2-sulfonated sodium styrene)biphenyl aqueous solution to the zinc-aluminum layered double hydroxide precursor of this embodiment was 30 mL / g. The pH was controlled at 8, and ion exchange was carried out at 80°C for 16 h. After washing and drying, the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was obtained. According to X-ray diffraction, based on the (003) crystal plane diffraction peak, the interlayer spacing of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was 1.30 nm, the content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl was 25 wt%, and the actual molar ratio of zinc to aluminum was 3.5:1.

[0100] III. Preparation of Surface-Coated Anti-Migration Stabilizing Intermediates

[0101] The fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was dispersed in a mixed medium of ethanol and water, with a volume ratio of ethanol to water of 1:4. The mass-to-volume ratio of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate in this embodiment was 0.20 g / mL, and dispersion was performed using ultrasonic dispersion. The ethanolamine-modified polypropylene grafted maleic anhydride compatible component of this embodiment was dissolved first and then added, with a mass ratio of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component to the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment of 1:3. The mixture was stirred at 80°C for 4 h. After filtration and drying at 80°C for 10 h, the surface-coated anti-migration stable intermediate of this embodiment was obtained. Thermogravimetric analysis showed that the coating amount of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component of this embodiment was 15 wt% of the total mass of the surface-coated anti-migration stable intermediate of this embodiment. According to laser particle size analysis, the median particle size D50 of the surface-coated anti-migration stabilizing intermediate in this embodiment is 2.0 μm.

[0102] IV. Preparation of Anti-migration Stabilizing Excipients for Fluorescent Whitening Agents

[0103] The surface-coated anti-migration stabilizing intermediate of this embodiment was pre-dried at 100°C for 8 hours. The pre-dried surface-coated anti-migration stabilizing intermediate (60.00 wt%), polypropylene carrier resin (37.00 wt%), bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (2.00 wt%), and 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol (1.00 wt%) were premixed for 20 minutes, with a total component content of 100 wt%. The melt flow rate of the polypropylene carrier resin in this embodiment was measured at 230°C and 2.16 kg, and was 30 g / 10 min. The mass ratio of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate to 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol in this embodiment was 2.0:1.

[0104] The mixture of this embodiment is melt-blended and granulated in a twin-screw extruder. The twin-screw extruder of this embodiment has a length-to-diameter ratio of 52:1, is equipped with a vacuum exhaust section, has a screw speed of 300 r / min, a residence time of 120 s, and the temperatures of each zone of the extruder from the feeding end to the die head are 180℃, 190℃, 200℃, and 210℃ respectively. Underwater pelletizing is used to obtain the anti-migration stabilizing excipient of the fluorescent whitening agent of this embodiment.

[0105] The total content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl in the anti-migration stabilizing excipient of the fluorescent whitening agent in this embodiment was determined to be 12.8 wt%. Under the conditions of 70°C and 168 h, the migration loss rate of 4,4'-bis(2-sulfonated sodium styrene)biphenyl in this embodiment was 7.8%, and the migration loss rate was expressed as the percentage difference in the content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl before and after aging relative to the content before aging.

[0106] Features of Example 2: This example employs a scheme combining a high proportion of surface-coated anti-migration stabilizing intermediates with a low proportion of polypropylene carrier resin, supplemented by a high mass ratio of light stabilizers and UV absorbers, forming a reinforced and stabilized system with a high proportion of functional components. Process parameters favoring reinforcement conditions are selected during preparation, including higher reaction temperatures, longer reaction times, and higher concentrations, to ensure sufficient reaction conditions. The coating process employs a high coating amount design, combined with high-temperature, long-duration drying conditions and a high-energy-input dispersion method to obtain intermediates with large particle sizes. The extrusion compounding utilizes a high-speed, high-temperature processing window and a long residence time, suitable for applications requiring high fluorescent whitening effects and strong anti-migration properties, particularly suitable for outdoor weather-resistant polypropylene products and functional masterbatches with high fluorescent whitening agent content.

[0107] Example 3

[0108] I. Preparation of Ethanolamine-Modified Polypropylene Grafted with Maleic Anhydride Compatible Component

[0109] 100g of polypropylene grafted with maleic anhydride and 950g of xylene were added to a reaction vessel equipped with a stirrer and a condenser. The mass ratio of polypropylene grafted with maleic anhydride to xylene was 1:9.5. The mixture was heated to 125°C to allow for complete dissolution. 4.5g of ethanolamine was added, bringing the mass ratio of polypropylene grafted with maleic anhydride to ethanolamine to 100:4.5. The reaction was carried out at 110°C for 2.5 hours. The residual anhydride group content was monitored by chemical titration. The reaction was terminated when the residual anhydride group content decreased to 0.3 wt%. After cooling the reaction solution, ethanol precipitant was added to precipitate the product, which was then filtered. The product was dried under vacuum at 75°C for 8 hours to obtain the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component of this embodiment.

[0110] II. Preparation of fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate

[0111] Zinc nitrate hexahydrate and aluminum nitrate nonahydrate were dissolved in deionized water, with the molar ratio of zinc to aluminum controlled at 3.0:1, to prepare a metal salt solution with a total metal ion concentration of 0.50 mol / L. Sodium hydroxide and sodium carbonate were prepared into an alkaline solution, with a sodium hydroxide concentration of 1.5 mol / L and a sodium carbonate concentration of 0.50 mol / L. The metal salt solution and the alkaline solution of this embodiment were co-precipitated by dropwise addition at 70°C, with the pH controlled at 10, and aged for 6 hours. The resulting precipitate was washed until the pH reached 7.5 and dried at 70°C for 10 hours to obtain a zinc-aluminum layered double hydroxide precursor.

[0112] The zinc-aluminum layered double hydroxide precursor of this embodiment was dispersed in an aqueous solution containing 4,4'-bis(2-sulfonated sodium styrene)biphenyl. The concentration of the 4,4'-bis(2-sulfonated sodium styrene)biphenyl aqueous solution in this embodiment was 25 g / L, and the liquid-to-solid ratio of the 4,4'-bis(2-sulfonated sodium styrene)biphenyl aqueous solution to the zinc-aluminum layered double hydroxide precursor of this embodiment was 15 mL / g. The pH was controlled at 7, and ion exchange was carried out at 70°C for 12 h. After washing and drying, the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was obtained. According to X-ray diffraction, based on the (003) crystal plane diffraction peak, the interlayer spacing of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was 1.10 nm, the content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl was 15 wt%, and the actual molar ratio of zinc to aluminum was 2.8:1.

[0113] III. Preparation of Surface-Coated Anti-Migration Stabilizing Intermediates

[0114] The fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was dispersed in a mixed medium of ethanol and water, with a volume ratio of ethanol to water of 1:2.5. The mass-to-volume ratio of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate in the ethanol-water mixed medium of this embodiment was 0.10 g / mL. Dispersion was carried out using mechanical stirring. The ethanolamine-modified polypropylene grafted maleic anhydride compatible component of this embodiment was first uniformly dispersed and then added. The mass ratio of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component to the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was 1:10. The mixture was stirred at 60°C for 2.5 h. After filtration, it was dried at 65°C for 7 h to obtain the surface-coated anti-migration stable intermediate of this embodiment. Thermogravimetric analysis showed that the coating amount of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component of this embodiment was 9 wt% of the total mass of the surface-coated anti-migration stable intermediate of this embodiment. According to laser particle size analysis, the median particle size D50 of the surface-coated anti-migration stabilizing intermediate in this embodiment is 1.0 μm.

[0115] IV. Preparation of Anti-migration Stabilizing Excipients for Fluorescent Whitening Agents

[0116] The surface-coated anti-migration stabilizing intermediate of this embodiment was pre-dried at 90°C for 5 hours. 40.00 wt% of the pre-dried surface-coated anti-migration stabilizing intermediate, 59.70 wt% of polypropylene carrier resin, 0.10 wt% of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, and 0.20 wt% of 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol were premixed for 10 minutes, with a total component content of 100 wt%. The melt flow rate of the polypropylene carrier resin in this embodiment was measured at 230°C and 2.16 kg, and was 15 g / 10 min. The mass ratio of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate to 2-(2H-benzotriazol-2-yl)-4,6-ditert-amylphenol in this embodiment was 0.5:1.

[0117] The mixture of this embodiment is melt-blended and granulated in a twin-screw extruder. The twin-screw extruder of this embodiment has a length-to-diameter ratio of 40:1, is equipped with a vacuum exhaust section, has a screw speed of 220 r / min, a residence time of 80 s, and the temperatures of each zone of the extruder from the feeding end to the die head are 170℃, 180℃, 190℃, and 200℃ respectively. Water-stretch granulation is used to obtain the anti-migration stabilizing excipient of the fluorescent whitening agent of this embodiment.

[0118] The total content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl in the anti-migration stabilizing excipient of the fluorescent whitening agent in this embodiment was determined to be 5.5 wt%. Under the conditions of 70°C and 168 h, the migration loss rate of 4,4'-bis(2-sulfonated sodium styrene)biphenyl in this embodiment was 5.5%, and the migration loss rate was expressed as the percentage difference in the content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl before and after aging relative to the content before aging.

[0119] Features of Example 3: This example employs a combination of a moderately high polypropylene carrier resin ratio and a moderate ratio of surface-coated anti-migration stabilizing intermediates, supplemented by a low content of light stabilizers and UV absorbers in a low mass ratio, forming a balanced, fundamentally stable system. Moderate process parameters, including moderate reaction temperature, reaction time, and concentration, are selected during the preparation process to create standardized preparation conditions. The coating process uses a moderate coating amount, coupled with moderate temperature and time drying conditions, to obtain intermediates with moderate particle sizes. The extrusion compounding uses a moderate speed and temperature processing window, suitable for conventional whitening applications of general-purpose polypropylene products, and particularly suitable for the standardized fluorescent whitening requirements of injection-molded and blow-molded polypropylene.

[0120] Example 4

[0121] I. Preparation of Ethanolamine-Modified Polypropylene Grafted with Maleic Anhydride Compatible Component

[0122] 100g of polypropylene grafted with maleic anhydride and 700g of xylene were added to a reaction vessel equipped with a stirrer and a condenser. The mass ratio of polypropylene grafted with maleic anhydride to xylene was 1:7. The mixture was heated to 120°C to allow for complete dissolution. 3g of ethanolamine was then added, bringing the mass ratio of polypropylene grafted with maleic anhydride to ethanolamine to 100:3. The reaction was carried out at 105°C for 2 hours. The residual anhydride group content was monitored by chemical titration. The reaction was terminated when the residual anhydride group content decreased to 0.4wt%. After cooling the reaction solution, an ethanol precipitant was added to precipitate the product, which was then filtered. The product was dried under vacuum at 70°C for 6 hours to obtain the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component of this embodiment.

[0123] II. Preparation of fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate

[0124] Zinc nitrate hexahydrate and aluminum nitrate nonahydrate were dissolved in deionized water, with the molar ratio of zinc to aluminum controlled at 2.5:1, to prepare a metal salt solution with a total metal ion concentration of 0.30 mol / L. Sodium hydroxide and sodium carbonate were prepared into an alkaline solution, with a sodium hydroxide concentration of 1.0 mol / L and a sodium carbonate concentration of 0.30 mol / L. The metal salt solution and the alkaline solution of this example were co-precipitated by dropwise addition at 65°C, with the pH controlled at 9.5, and aged for 5 hours. The resulting precipitate was washed until the pH reached 7.2 and dried at 65°C for 9 hours to obtain a zinc-aluminum layered double hydroxide precursor.

[0125] The zinc-aluminum layered double hydroxide precursor of this embodiment was dispersed in an aqueous solution containing 4,4'-bis(2-sulfonated sodium styrene)biphenyl. The concentration of the 4,4'-bis(2-sulfonated sodium styrene)biphenyl aqueous solution in this embodiment was 15 g / L, and the liquid-to-solid ratio of the 4,4'-bis(2-sulfonated sodium styrene)biphenyl aqueous solution to the zinc-aluminum layered double hydroxide precursor of this embodiment was 20 mL / g. The pH was controlled at 7.5, and ion exchange was carried out at 65°C for 10 h. After washing and drying, the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was obtained. According to X-ray diffraction, based on the (003) crystal plane diffraction peak, the interlayer spacing of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was 1.05 nm, the content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl was 12 wt%, and the actual molar ratio of zinc to aluminum was 2.5:1.

[0126] III. Preparation of Surface-Coated Anti-Migration Stabilizing Intermediates

[0127] The fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment was dispersed in a mixed medium of ethanol and water, with a volume ratio of ethanol to water of 1:3. The mass-to-volume ratio of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate in this embodiment was 0.05 g / mL, and dispersion was performed using ultrasonic dispersion. The ethanolamine-modified polypropylene grafted maleic anhydride compatible component of this embodiment was first uniformly dispersed and then added, with a mass ratio of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component to the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate of this embodiment of 1:12. The mixture was stirred at 55°C for 2 h. After filtration and drying at 60°C for 6 h, the surface-coated anti-migration stable intermediate of this embodiment was obtained. Thermogravimetric analysis determined that the coating amount of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component of this embodiment was 7 wt% of the total mass of the surface-coated anti-migration stable intermediate of this embodiment. According to laser particle size analysis, the median particle size D50 of the surface-coated anti-migration stabilizing intermediate in this embodiment is 0.5 μm.

[0128] IV. Preparation of Anti-migration Stabilizing Excipients for Fluorescent Whitening Agents

[0129] The surface-coated anti-migration stabilizing intermediate of this embodiment was pre-dried at 85°C for 4 hours. The pre-dried surface-coated anti-migration stabilizing intermediate (30.00 wt%), polypropylene carrier resin (68.50 wt%), bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (1.00 wt%), and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol (0.50 wt%) were premixed for 15 minutes, with a total component content of 100 wt%. The melt flow rate of the polypropylene carrier resin in this embodiment was measured at 230°C and 2.16 kg, and was 10 g / 10 min. The mass ratio of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate to 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol in this embodiment was 2.0:1.

[0130] The mixture of this embodiment was melt-blended and granulated in a twin-screw extruder. The twin-screw extruder of this embodiment had a length-to-diameter ratio of 45:1, a vacuum exhaust section, a screw speed of 250 r / min, a residence time of 90 s, and extruder temperatures of 165°C, 175°C, 185°C, and 195°C from the feed end to the die head, respectively. Underwater pelleting was used to obtain the anti-migration stabilizing excipient of the fluorescent whitening agent of this embodiment.

[0131] The total content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl in the anti-migration stabilizing excipient of the fluorescent whitening agent in this embodiment was determined to be 3.3 wt%. Under the conditions of 70°C and 168 h, the migration loss rate of 4,4'-bis(2-sulfonated sodium styrene)biphenyl in this embodiment was 4.5%, and the migration loss rate was expressed as the percentage difference in the content of 4,4'-bis(2-sulfonated sodium styrene)biphenyl before and after aging relative to the content before aging.

[0132] Features of Example 4: This example employs a combination of a moderately high polypropylene carrier resin ratio and a moderately low ratio of a surface-coated, anti-migration stabilizing intermediate, supplemented with a moderate amount of light stabilizer and UV absorber in a relatively high mass ratio, forming a carrier-dominated optimized stabilization system. The preparation process uses moderately low process parameters, including moderately low reaction temperature, moderate reaction time, and moderate concentration, creating mild and optimized preparation conditions. The coating process employs a moderately low coating amount, combined with moderate temperature and time drying conditions, to obtain intermediates with moderately small particle sizes. The extrusion compounding utilizes a medium-to-high speed and medium temperature processing window, suitable for applications requiring good processing performance and moderate fluorescent whitening effects, particularly suitable for the balanced performance requirements of film-grade and fiber-grade polypropylene.

[0133] Comparative Example 1: Basically the same as Example 1, except that in step S2, the content of the surface-coated anti-migration stabilizing intermediate is 15.00 wt%, the content of polypropylene carrier resin is adjusted to 81.00 wt%, the content of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol is kept at 2.00 wt%, and the amounts of other components and preparation conditions remain unchanged.

[0134] Comparative Example 2: Basically the same as Example 1, except that in the preparation of the surface-coated anti-migration stable intermediate, the mass ratio of the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component to the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate was changed to 1:40. After stirring at 40°C for 1 hour, the mixture was filtered and dried at 50°C for 4 hours to obtain an intermediate with a coating amount of 1.50 wt%. The amounts of other components and the preparation conditions remained unchanged.

[0135] Comparative Example 3: Basically the same as Example 1, except that in the preparation of the surface-coated anti-migration stable intermediate, the mass-to-volume ratio of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate in the ethanol and water mixed medium was changed to 0.25 g / mL. Under the same conditions, dispersion, coating, filtration and drying were completed to obtain an intermediate with a median particle size D50 of 2.50 μm. The amount of other components and preparation conditions remained unchanged.

[0136] Comparative Example 4: Basically the same as Example 1, except that in step S2, a polypropylene carrier resin with a melt flow rate of 35 g / 10 min was used, and the amounts of the surface-coated anti-migration stabilizing intermediate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol remained unchanged, while other preparation conditions remained unchanged.

[0137] Comparative Example 5: Basically the same as Example 1, except that in step S2, the content of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate is 0.10 wt%, the content of 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol is 2.00 wt%, the content of polypropylene carrier resin is adjusted to 76.90 wt%, and the amounts of other components and preparation conditions remain unchanged.

[0138] Comparative Example 6: It is basically the same as Example 1, except that before step S2, the pre-drying conditions of the surface-coated anti-migration stable intermediate are changed to 60°C for 1 hour, while the subsequent premixing, extrusion and granulation conditions remain unchanged.

[0139] Comparative Example 7: It is basically the same as Example 1, except that the screw speed of the twin-screw extruder in step S3 is changed to 320 r / min, while the residence time, temperature of each zone, granulation method and dosage of other components remain unchanged.

[0140] Comparative Example 8: Essentially the same as Example 1, except that in step three, the ethanolamine-modified polypropylene grafted maleic anhydride compatible component was not added during the preparation of the surface-coated anti-migration stabilizing intermediate. Instead, the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate was directly filtered and dried at 50°C for 4 hours before being used in subsequent batching. In step S2, 21.00 wt% of the uncoated fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate replaced the surface-coated anti-migration stabilizing intermediate. The amounts of other components and preparation conditions remained unchanged. This comparative example was used to verify the synergistic effect of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate and the surface coating of the ethanolamine-modified polypropylene grafted maleic anhydride compatible component.

[0141] Comparative Example 9: Essentially the same as Example 1, except that in step two, the ion exchange step B4 was omitted when preparing the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate. Instead of intercalating with 4,4'-bis(2-sulfonate sodium styrene)biphenyl, the zinc-aluminum layered double hydroxide precursor was mechanically mixed with an aqueous solution of 4,4'-bis(2-sulfonate sodium styrene)biphenyl at room temperature for 30 minutes, filtered, dried, and then surface-coated according to step three of Example 1. In step S2, the obtained material was still prepared at 21.00 wt%, and the amounts of other components and preparation conditions remained unchanged. This comparative example was used to verify the synergistic effect of intercalation confinement and surface coating interface construction.

[0142] Comparative Example 10: Essentially the same as Example 1, except that 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol was not added in step S2; instead, 2.00 wt% of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate was added, and the content of the polypropylene carrier resin was adjusted accordingly to 77.00 wt%. The amounts of other components and preparation conditions remained unchanged. This comparative example was used to verify the synergistic effect of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol.

[0143] Performance testing:

[0144] In the examples and comparative examples, the fluorescent whitening agent anti-migration stabilizing excipient tablets were placed at 70°C for 24, 72, 120, and 168 hours. The peak area change of 4,4'-bis(2-sulfonate styryl)biphenyl was detected by DMF / water mixed solvent extraction and external standard method in high-performance liquid chromatography. The tablet thickness was controlled at 2.0 mm, and five parallel samples were tested in each group. The migration loss rate was calculated by comparing the content difference before and after heat aging, using the formula: Migration loss rate = (C0 - C...) / (C...) t The result is reported as mean ± standard deviation and is used to evaluate the migration stability of fluorescent whitening agents under thermal aging conditions.

[0145] The injection-molded standard specimens corresponding to the examples and comparative examples underwent accelerated aging tests under fluorescent ultraviolet lamp irradiation to evaluate their whiteness retention ability after photoaging. A UVA-340 light source was used, the black panel temperature was controlled at 60℃, and the test was conducted according to the set light / condensation cycle mode. Whiteness values ​​were measured at 0 hours, 72 hours, and 168 hours. Five parallel samples were tested in each group. The whiteness retention rate was calculated as W... t The whiteness change after photoaging is calculated using / W0×100%, and the results are reported as mean ± standard deviation, which is used to characterize the light aging resistance of the material.

[0146] The fluorescent whitening agent anti-migration stabilizing excipient granules corresponding to the examples and comparative examples were pre-dried and then subjected to melt flow rate tests at 230°C and 2.16 kg load. Five parallel tests were performed on each sample group. After removing outliers, the mean ± standard deviation was calculated, and the results were combined with extrusion stability analysis to evaluate the material's processing fluidity and processing window width.

[0147] The notched impact specimens used in the examples and comparative examples were evaluated for system toughness through cantilever beam impact testing. Standard injection-molded specimens were notched with a V-shape, conditioned at 23°C and 50% relative humidity, and tested, with ten parallel specimens per group. The impact resistance and embrittlement tendency of the materials were characterized by determining the energy required for impact failure. The results were statistically analyzed as the mean ± standard deviation of the notched cantilever beam impact strength.

[0148] The tensile specimens corresponding to the examples and comparative examples were subjected to uniaxial tensile tests at 23°C to evaluate the degree of disturbance of the continuous phase and the fracture elongation. Stress-strain curves were recorded at a constant rate. Five parallel specimens were tested in each group, and the tensile strength and elongation at break data were output. The results were reported in the form of mean ± standard deviation to characterize the mechanical properties and deformation capacity of the materials.

[0149] The fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediates corresponding to the examples and comparative examples were characterized by low-angle powder X-ray diffraction. Original diffraction patterns were acquired in the range of 2θ = 2°–15° with a step size of 0.02°, and the data were output in CSV format. The interlayer spacing d was calculated according to Bragg's law based on the position of the characteristic peak (003). 003 The peak position, interlayer spacing, and repeatability data are provided to evaluate the intercalation degree of fluorescent whitening agents in layered double hydroxides.

[0150] The coating amount of the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component was evaluated by thermogravimetric analysis (TGA) for the surface-coated anti-migration stabilizing intermediates corresponding to the examples and comparative examples. Under a nitrogen atmosphere, the samples were heated from room temperature to 800°C at a rate of 10°C / min, and TG / DTG curves were obtained. Three parallel samples were tested in each group. The mass fraction of the organic coating layer was calculated by integrating the target weight loss interval. The results were output as mean ± standard deviation to characterize the effectiveness of the coating process.

[0151] The intermediate powders in the examples and comparative examples were evaluated for agglomeration and particle size distribution using wet laser diffraction particle size analysis. After ultrasonic dispersion for 2 minutes, the samples were tested based on the measured refractive index input parameters, with three parallel measurements per group. Based on the volume distribution curve retrieved from the laser scattering signal, the D10, D50, and D90 particle size parameters and distribution width were output, and the original particle size-distribution CSV data was exported to characterize the powder's dispersibility and particle size window.

[0152] Figure 1 The TGA and DTG curves of Example 1 and Comparative Example 8 are shown. Thermogravimetric analysis was used to compare the thermogravimetric behavior and thermal decomposition characteristics of the samples. Example 1 showed a clearer stepwise weight loss process and a higher thermal stability onset temperature, indicating that its coating and interface bonding were more sufficient, which is beneficial to improving the thermal stability of the system.

[0153] Figure 2 The laser particle size distribution frequency curves for Example 1 and Comparative Example 3 are shown. The particle size distribution characteristics were characterized by laser particle size analysis. The particle size distribution of Example 1 is more concentrated and mainly located in the smaller particle size range, indicating that the obtained particles have better dispersibility and more uniform particle size control, which is beneficial to the stable distribution and interface transfer in the subsequent system.

[0154] Figure 3 The cumulative particle size distribution curves of Example 1 and Comparative Example 3 are shown. The cumulative particle size distribution characteristics of the samples were further compared using the laser particle size analysis method. The cumulative distribution of Example 1 rises more steeply and is concentrated in a narrower particle size range, indicating that its particle size uniformity is higher, reflecting that the particle size control during the preparation process is more effective.

[0155] Figure 4 The FTIR spectra of Example 1 and Comparative Example 8 are shown. The functional group composition and interfacial interaction characteristics of the samples were analyzed by Fourier transform infrared spectroscopy. The signal changes in the carbonyl and related characteristic absorption regions of Example 1 were more obvious, indicating that more complete interfacial interactions and surface modification occurred in the system, which verified the rationality of the component design.

[0156] Figure 5 The UV aging whiteness retention rate curves for Example 1, Comparative Example 10, and Comparative Example 5 are shown. The UV aging test method was used to evaluate the whiteness retention ability of the samples under continuous light conditions. Example 1 showed a higher whiteness retention rate at each aging time point, indicating that it has stronger resistance to UV decay and can better maintain the stability of the system.

[0157] Figure 6 The graphs show the migration loss rate kinetics of Example 1 and Comparative Example 10. The migration behavior of the effective components in the samples was evaluated by using thermal aging combined with chromatographic quantification. Example 1 showed a consistently low migration loss rate throughout the aging process, indicating that it had a better fixation and inhibition effect on the fluorescent whitening components, demonstrating a superior stability retention effect.

[0158] Figure 7 This is a macroscopic optical photograph of the anti-migration stabilizing excipient for the fluorescent whitening agent prepared in Example 1. The sample exhibits a regular cylindrical granule morphology with a light grayish-white surface, uniform gloss, good flowability, and no agglomeration or adhesion. The granules within the same batch show high consistency in color and size, with no discoloration, cracks, or irregular shapes observed. This reflects the reasonable setting of the twin-screw extrusion mixing process parameters and the effective use of water-jet granulation to ensure the dimensional uniformity and surface quality of the product. It also proves that the low-temperature, low-speed processing window achieves sufficient plasticization and uniform dispersion of the material.

[0159] Figure 8 Scanning electron microscope image of the anti-migration stabilizing excipient for the fluorescent whitening agent prepared in Example 1. Figure 8(a) The low magnification image shows that the particle cross-section is dense and uniform, with no macroscopic cracks or phase separation. Figure 8 (b) The medium magnification image reveals that the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide is distributed in a plate-like morphology in the polypropylene matrix. Figure 8 (c,d) High-magnification images show that the layered double hydroxide sheets are tightly bonded to the polypropylene matrix interface, with no debonding or void defects. The sheet surface exhibits a step-like growth texture with irregularly serrated edges, and the matrix fracture surface shows ductile fracture characteristics. This demonstrates that a 3% coating of the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component achieves effective interface modification and compatibility, ensuring the nanoscale dispersion and interfacial strength of the inorganic filler phase.

[0160] Table 1 Performance summary of examples and comparative examples

[0161] Sample number Interlayer spacing / nm Coating amount / wt% D50 / μm <![CDATA[MFR / g·10min -1 ]]> Migration loss rate / % UV whiteness retention rate / % <![CDATA[Izod impact / kJ·m -2 > Elongation at break / % Example 1 0.90±0.02 3.0±0.2 0.10±0.01 7.1±0.3 3.2±0.2 92.8±1.2 10.6±0.4 142±6 Example 2 1.30±0.03 15.0±0.4 2.00±0.08 8.8±0.4 7.8±0.3 94.6±1.0 9.1±0.3 132±5 Example 3 1.10±0.02 9.0±0.3 1.00±0.05 7.9±0.3 5.5±0.2 91.4±1.1 12.7±0.5 176±7 Example 4 1.05±0.02 7.0±0.3 0.50±0.03 8.3±0.3 4.5±0.2 93.2±1.0 13.6±0.5 188±8 Comparative Example 1 0.90±0.02 3.0±0.2 0.10±0.01 8.0±0.4 8.6±0.3 84.1±1.4 8.3±0.4 118±6 Comparative Example 2 0.90±0.02 1.5±0.1 0.14±0.02 7.6±0.3 9.1±0.3 82.6±1.5 7.8±0.4 110±5 Comparative Example 3 0.90±0.03 3.0±0.2 2.50±0.10 5.9±0.3 8.8±0.4 83.5±1.3 6.7±0.3 96±5 Comparative Example 4 0.90±0.02 3.0±0.2 0.10±0.01 12.6±0.5 8.4±0.3 85.2±1.4 7.2±0.3 104±6 Comparative Example 5 0.90±0.02 3.0±0.2 0.10±0.01 7.3±0.3 8.7±0.3 79.4±1.6 8.0±0.4 116±6 Comparative Example 6 0.90±0.02 3.0±0.2 0.12±0.02 6.5±0.3 8.2±0.3 84.8±1.4 7.5±0.4 109±5 Comparative Example 7 0.90±0.02 3.0±0.2 0.11±0.01 9.5±0.4 8.9±0.4 83.7±1.5 6.9±0.3 101±5 Comparative Example 8 0.90±0.02 0.0±0.0 0.18±0.02 6.1±0.3 10.8±0.4 81.3±1.5 6.4±0.3 88±4 Comparative Example 9 0.76±0.02 3.0±0.2 0.22±0.03 5.7±0.3 11.6±0.5 78.6±1.7 5.9±0.3 81±4 Comparative Example 10 0.90±0.02 3.0±0.2 0.10±0.01 7.2±0.3 8.3±0.3 80.1±1.5 8.1±0.4 114±5

[0162] As can be seen from the performance of the embodiments and comparative examples in Table 1, Examples 1-4 all fall within the balance window determined by interlayer spacing, coating amount, and particle size. Therefore, they are generally superior to the comparative examples in terms of migration loss rate, UV whiteness retention rate, notched impact strength, and elongation at break. Among them, Example 1 is the most outstanding in terms of low migration, Example 4 is the best in terms of toughness and processing balance, Example 3 demonstrates robustness under medium structural parameters, and Example 2 proves that it can still maintain acceptable overall performance under higher functional component loading. In contrast, the conventional comparative examples suffer from decreased fixation efficiency, deteriorated dispersion, or unbalanced processing window due to deviations in formulation, process, or particle size. However, the synergistic comparative examples show a synchronous decline in migration, weather resistance, and toughness after disassembling the intercalation-coating interface or the compounded stable system, indicating that the solution of the present invention is not caused by a single factor, but is the result of the coupling of multiple technical units.

[0163] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any equivalent structural transformations made under the concept of the present invention and using the contents of the specification and drawings of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A fluorescent whitening agent anti-migration stabilizing excipient, characterized in that, The product includes the following components, each in wt%, and the total content of all components is 100 wt%: (1) 21-60wt% of surface-coated anti-migration stabilizing intermediates; (2) 36-75wt% polypropylene carrier resin; (3) 0.10-2.00 wt% of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate; (4) 0.10-2.00 wt% of 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol; The surface-coated anti-migration stabilizing intermediate includes a fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate, and an ethanolamine-modified polypropylene grafted with maleic anhydride compatible component coated on the surface of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate. The fluorescent whitening agent is 4,4'-bis(2-sodium styryl sulfonate)biphenyl; The interlayer spacing of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is 0.90-1.30 nm, and the coating amount of the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component is 3-15 wt% of the total mass of the surface-coated anti-migration stable intermediate.

2. The fluorescent whitening agent anti-migration stabilizing excipient according to claim 1, characterized in that, The ethanolamine-modified polypropylene grafted with maleic anhydride compatible component was prepared through the following steps: A1. Add polypropylene grafted with maleic anhydride and xylene to a reaction vessel. The mass ratio of polypropylene grafted with maleic anhydride to xylene is 1:4 to 1:

15. Heat the mixture to 110-140℃ to dissolve it. A2. Add ethanolamine, and the mass ratio of polypropylene grafted with maleic anhydride to ethanolamine is 100:1 to 100:

8. React at 90-130℃ for 1-4 hours. A3. Terminate the reaction when the residual anhydride group content is not higher than 0.5 wt%. A4. After cooling the reaction solution, allow the product to precipitate and filter it. Then, dry it at 60-90℃ for 4-12 hours to obtain the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component.

3. The fluorescent whitening agent anti-migration stabilizing excipient according to claim 1, characterized in that, The fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is prepared through the following steps: B1. Dissolve zinc nitrate hexahydrate and aluminum nitrate nonahydrate in deionized water, controlling the molar ratio of zinc to aluminum to be 2.0-4.0:1, to obtain a metal salt solution; B2. Prepare an alkaline solution by mixing sodium hydroxide and sodium carbonate, and co-precipitate the metal salt solution with the alkaline solution at 60-80℃, controlling the pH to 9-11, and aging for 4-8 hours; B3. The obtained precipitate was washed until the pH was 7-8 and dried at 60-80℃ for 8-12 h to obtain the zinc-aluminum layered double hydroxide precursor; B4. Disperse the zinc-aluminum layered double hydroxide precursor in an aqueous solution containing the fluorescent whitening agent, control the pH to 6-8, and carry out ion exchange at 60-80℃ for 8-16 hours; B5. Wash and dry to obtain the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate with an interlayer spacing of 0.90-1.30 nm.

4. The fluorescent whitening agent anti-migration stabilizing excipient according to claim 1, characterized in that, The surface-coated anti-migration stabilizing intermediate is prepared through the following steps: C1. The fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is dispersed in a mixed medium of ethanol and water, wherein the volume ratio of ethanol to water is 1:1 to 1:

4. C2. Add ethanolamine-modified polypropylene grafted with maleic anhydride compatible component, wherein the mass ratio of the amount of ethanolamine-modified polypropylene grafted with maleic anhydride compatible component to the mass ratio of the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is 1:3 to 1:

20. C3. Stir at 40-80℃ for 1-4 hours; C4. Filter and dry at 50-80℃ for 4-10h to obtain the surface-coated anti-migration stable intermediate, wherein the coating amount of the ethanolamine-modified polypropylene grafted with maleic anhydride compatible component is 3-15wt% of the total mass of the surface-coated anti-migration stable intermediate.

5. The fluorescent whitening agent anti-migration stabilizing excipient according to claim 1, characterized in that, At least one of the following technical features is true: In the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate, the content of the fluorescent whitening agent is 5-25 wt%. The actual molar ratio of zinc to aluminum in the fluorescent whitening agent intercalated zinc-aluminum layered double hydroxide intermediate is 2.2-3.5:1; The median particle size D50 of the surface-coated anti-migration stabilizing intermediate is 0.1-2.0 μm.

6. The fluorescent whitening agent anti-migration stabilizing excipient according to claim 1, characterized in that, At least one of the following technical features is true: The melt flow rate of the polypropylene carrier resin is 2-30 g / 10 min. The mass ratio of the bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate to the 2-(2H-benzotriazol-2-yl)-4,6-ditert-pentylphenol is 0.5-2.0:

1.

7. A method for preparing a fluorescent whitening agent anti-migration stabilizing excipient as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Provides a prepared surface-coated anti-migration stabilizing intermediate; S2. The surface-coated anti-migration stabilizing intermediate, polypropylene carrier resin, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol provided in step S1 are mixed, wherein the content of each component is in wt%, the content of the surface-coated anti-migration stabilizing intermediate is 21-60 wt%, the content of the polypropylene carrier resin is 36-75 wt%, the content of the bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate is 0.10-2.00 wt%, the content of the 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol is 0.10-2.00 wt%, and the total content of each component is 100 wt%. S3. The mixture obtained in step S2 is melt-blended and granulated in a twin-screw extruder at 160-210℃ to obtain a fluorescent whitening agent anti-migration stabilizing excipient.

8. The preparation method according to claim 7, characterized in that, At least one of the following process characteristics is true: The premixing time for each component in step S2 is 3-20 min; In step S3, the screw speed is 150-300 r / min, and the residence time is 45-120 s; In step S3, the temperatures of each zone of the extruder from the feeding end to the die head are 160-180℃, 170-190℃, 180-200℃ and 190-210℃ respectively. The granulation method after step S3 is water-stretching granulation or underwater pelletizing.

9. The preparation method according to claim 7, characterized in that, Before step S2, the surface-coated anti-migration stabilizing intermediate provided in step S1 is pre-dried at 80-100℃ for 2-8 hours.

10. The preparation method according to claim 7, characterized in that, The fluorescent whitening agent anti-migration stabilizing excipient obtained in step S3 has at least one of the following product characteristics: The total content of 4,4'-bis(2-sulfonate styryl)biphenyl is 0.5-10 wt%; Under conditions of 70℃ and 168h, the migration loss rate of 4,4'-bis(2-sulfonate styryl)biphenyl is no higher than 8%.

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