Supramolecular cage modified hindered amine light stabilizer as well as preparation method and application thereof

Abstract

The invention discloses a supramolecular cage modified hindered amine light stabilizer as well as a preparation method and application thereof, and belongs to the field of compound modification. The hindered amine light stabilizer in the light stabilizer is distributed in the cavity of the molecular cage with the hollow structure; the preparation method comprises the following steps: (1) preparing a solution containing a supramolecular cage; (2) preparing a solution containing a hindered amine light stabilizer; and (3) adding the solution containing the hindered amine light stabilizer into the solution containing the supramolecular cage, heating to react, adding a precipitation solvent after the reaction is finished, and washing and drying the obtained precipitate. According to the present invention, the combination ability of the molecular cage and the hindered amine light stabilizer is adjusted so as to improve the oxidation resistance of the molecular cage applied to the polymer, the synthesized molecular cage has the tetrahedral structure, the cavity of the molecular cage has the high hydrophobicity and the rich hydrogen bond binding sites, and the amino functional group existing on the surface of the molecular cage is utilized to improve the oxidation resistance of the polymer; the binding capacity of the molecular cage and the polymer is enhanced, so that the stability of the material is improved.

Description

Technical Field

[0001] The invention belongs to the field of compound modification, and in particular relates to a supramolecular cage-modified hindered amine light stabilizer and a preparation method and application thereof. Background Art

[0002] Polymer materials are closely related to people's lives. Common organic polymer materials include plastic films, coatings, polypropylene, polyvinyl chloride, polystyrene, polyacrylonitrile and nylon, etc. These materials are widely used in various engineering fields. Among them, outdoor engineering materials account for a considerable proportion. Due to long-term exposure to the outdoors, these materials are affected by external factors, shortening their service life and reducing their performance. Factors affecting material properties include physical factors, chemical factors and other factors. Physical factors include heat, light radiation and ambient temperature; chemical factors include oxygen, ozone, acid rain and alkali in the air. The main cause of polymer material aging is ultraviolet radiation from the sun. In order to protect outdoor engineering materials from photolysis and oxidation, people have studied and applied a series of polymer material additives with chemical functions. These additives include light stabilizers, antioxidants, heat stabilizers and flame retardants. Among them, light stabilizers are an important type of additives, and their mechanism of action and application fields have been widely studied.

[0003] Hindered amine light stabilizers (HALS) are a type of organic polymer material additives with excellent light stability and thermal stability. Due to its low cost and low toxicity, HALS is widely used in various industrial fields and has good compatibility with most polymers. Its light stabilization effect is better than other types of ultraviolet absorbers, making it one of the most widely used additives in industry. As a new type of light stabilizer, HALS is considered to be one of the most promising materials. However, traditional HALS generally has high alkalinity and is easily converted into salts when in contact with acidic substances produced during polymer processing and use, thereby reducing the activity of the piperidine amino group and limiting its synergistic stabilization effect with halogen-containing resins and acidic resins. In order to solve this problem, the current popular method is to protect the N atom in piperidine with an alkyl group, but this will lead to a decrease in its antioxidant capacity.

[0004] Therefore, developing a HALS derivative that has both acid resistance and high antioxidant capacity is a key issue that needs to be solved urgently. Summary of the invention

[0005] Purpose of the invention: The first purpose of the present invention is to provide a supramolecular cage-modified hindered amine light stabilizer with acid resistance and high-efficiency antioxidant capacity. The second purpose of the present invention is to provide a preparation method of the above supramolecular cage-modified hindered amine light stabilizer. The third purpose of the present invention is to provide an application of the above supramolecular cage-modified hindered amine light stabilizer.

[0006] Technical solution: In the hindered amine light stabilizer modified by supramolecular cages provided by the present invention, the hindered amine light stabilizer is distributed inside the cavity of the molecular cage with a hollow structure.

[0007] Further, the supramolecular cage is prepared by reacting a divalent transition metal ion as a node and tetra(4-aminophenyl)methane (TAPM) as a ligand.

[0008] Further, the divalent transition metal ion is a zinc ion.

[0009] Further, the hindered amine light stabilizer includes 2,2,6,6-tetramethylpiperidinol (TMP), 2,2,6,6-tetramethylpiperidineamine (TAD), or 2,2,6,6-tetramethylpiperidone (TAA), and the molecular formulas are as follows:

[0010]

[0011] In the present invention, through the supramolecular coordination self-assembly method, a tridentate chelating ligand coordinates with metal ions to form a molecular cage with a hollow structure, and its cavity is used to encapsulate the guest hindered amine molecules through van der Waals forces.

[0012] The present invention provides a preparation method of the above-mentioned hindered amine light stabilizer modified by supramolecular cages, including the following steps:

[0013] (1) Prepare a solution containing supramolecular cages;

[0014] (2) Prepare a solution containing a hindered amine light stabilizer;

[0015] (3) Slowly add the solution containing the hindered amine light stabilizer to the solution containing supramolecular cages, carry out a heating reaction, and then add a precipitation solvent after completion. The obtained precipitate is washed and dried to obtain the hindered amine light stabilizer modified by supramolecular cages.

[0016] Further, in step (1), the preparation process of the solution containing supramolecular cages is as follows: Dissolve tetra(4-aminophenyl)methane and pyridine-2-carboxaldehyde in an organic solvent to obtain a mixed solution, and then slowly add a divalent transition metal ion salt, and heat and stir to obtain it.

[0017] Further, the molar ratio of the tetra(4-aminophenyl)methane (TAPM), pyridine-2-carboxaldehyde and divalent transition metal ion salt is 1:3-4:1-2, preferably 1:3:1; the concentration of the tetra(4-aminophenyl)methane in the mixed solution is 1-100 mM, preferably 10-20 mM; the divalent transition metal ion salt is zinc trifluoromethanesulfonate; the rate of the slow addition is: 5-10 mL / min; the conditions of the heating and stirring are: reacting at 70±5 °C for 2-24 h, preferably 10-24 h.

[0018] Further, in step (2), the preparation method of the solution containing the hindered amine light stabilizer is: dissolving the hindered amine light stabilizer in an organic solvent and stirring and mixing to obtain; the concentration of the hindered amine light stabilizer in the solution containing the hindered amine light stabilizer is 1-50 mM, preferably 10-50 mM.

[0019] Further, the organic solvent is acetonitrile.

[0020] Further, in step (3), the rate of the slow addition is: 2-2.5 mL / min; the conditions of the heating reaction are: reacting at 70±5 °C for 5-6 h; the precipitation solvent is an ether solvent, preferably isopropyl ether.

[0021] Further, the volume ratio of the solution containing the supramolecular cage and the solution containing the hindered amine light stabilizer is (1:1-6).

[0022] The present invention provides an application of the above-mentioned supramolecular cage-modified hindered amine light stabilizer in polymer melt spinning.

[0023] Further, the polymer includes nylon 6, nylon 66 and polyethylene terephthalate.

[0024] Principle of the invention: By designing a novel ligand and a supramolecular coordination self-assembly mechanism, the present invention prepares a class of molecular cages with high stability and strong selectivity. The molecular cage is formed by self-assembly of a specific ligand and metal ions in an acetonitrile solution, and has a specific cavity structure, which can efficiently recognize and encapsulate the target hindered amine molecules. By adding an ether solvent to the composite solution of the molecular cage and the hindered amine, the composite is transformed from a solution state to a solid state that is more convenient for storage and transportation. Experiments show that the composite formed by the molecular cage and the hindered amine exhibits excellent performance in the antioxidant experiment and has broad application prospects.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following remarkable effects: (1) The molecular cage synthesized by the present invention has a relatively large cavity structure for accommodating guest molecules - hindered amine light stabilizers, and the amino groups on the outer surface of the molecular cage contribute to enhancing the binding force between the molecular cage and the polymer, thereby improving the stability of the polymer material; (2) The structure of the hindered amine light stabilizer modified by the supramolecular cage synthesized by the present invention is stable, effectively reducing the possibility of HALS overflow, reducing the quenching of TMP by acidic functional groups in high molecular polymer substrates such as nylon 6, nylon 66, and polyethylene terephthalate, and improving the antioxidant efficiency of HALS. Compared with the TMP and nylon 6 composite without adding the molecular cage, the antioxidant time is increased by 4 times; (3) The preparation method of the present invention is relatively convenient and has a relatively low cost, without the participation of other irrelevant substances, facilitating the purification of the material, and having a broad application prospect. Description of the Drawings

[0026] Figure 1 1H NMR spectrum of the hindered amine light stabilizer TMP@Zn4L4 modified by the supramolecular cage prepared in Example 1;

[0027] Figure 2 Thermal stability diagram of the hindered amine light stabilizer TMP@Zn4L4 modified by the supramolecular cage prepared in Example 1;

[0028] Figure 3 Photostability diagram of the hindered amine light stabilizer TMP in nylon;

[0029] Figure 4 Photostability diagram of the hindered amine light stabilizer TMP@Zn4L4 modified by the supramolecular cage prepared in Example 1 in nylon. Detailed Description of the Invention

[0030] The present invention will be further described in detail below with reference to the examples and the drawings.

[0031] Example 1: The hindered amine light stabilizer TMP@Zn4L4 modified by the supramolecular cage provided in this example is prepared as follows:

[0032] (1) Prepare a mixed acetonitrile solution of 10 mM TAPM and 30 mM pyridine-2-carboxaldehyde, and slowly drip it into a 10 mM zinc trifluoromethanesulfonate (Zn(OTf)2) solution at a rate of 8 mL / min, and stir and react at 70 °C for 10 h to obtain a Zn4L4 solution;

[0033] (2) Prepare a 10 mM acetonitrile solution of TMP, and slowly add it to the above Zn4L4 solution at a rate of 2 mL / min. The volume ratio of the Zn4L4 solution to the TMP acetonitrile solution is 1:6, and then stir and react at 70 °C for 5 h;

[0034] (3) Add 500 mL of isopropyl ether to the above-mentioned mixed solution, a large amount of purple precipitate will be produced. Filter the obtained precipitate, wash it with 200 mL of isopropyl ether, and dry it under vacuum to obtain the target product TMP@Zn4L4.

[0035] Application Example 1: Apply the TMP@Zn4L4 prepared in Example 1 to nylon spinning. The preparation steps are as follows:

[0036] S1. Place the TMP@Zn4L4 prepared in Example 1 in a mill and crush and grind it into a hindered amine powder with a particle size of 10 to 20 microns.

[0037] S2. Put the hindered amine powder and nylon chips together in a stainless-steel stirrer at a mass ratio of 20% and stir for 30 - 45 min at a stirring speed of 500 r / min to obtain mixed nylon particles.

[0038] S3. Add the nylon particles mixed with 20% of the hindered amine material into a masterbatch manufacturing machine for melting (melting temperature 220 - 235 °C), extrusion, water cooling, and pelletizing to obtain a hindered amine-based supramolecular nylon masterbatch.

[0039] S4. Add the hindered amine-based supramolecular nylon masterbatch to the nylon spinning screw at a weight ratio of 1% - 3.5%. Extrude and spin at a melting temperature of 230 - 235 - 220 - 215 °C in each zone of the screw. After cooling with side blowing air, introduce it between draw roll 1 and draw roll 2 for stretching at a ratio of 1.5 - 1.6 times, with a stretching speed of 4100 - 4500 m / min. Finally, wind it into a cake on a winder at a speed of 4200 - 4600 m / min to obtain polyamide filaments with high antioxidant performance.

[0040] Perform performance tests on the materials prepared in Example 1 and Application Example 1. The results are shown in Figures 1-4 .

[0041] It can be seen from the nuclear magnetic resonance spectrum ( Figure 1 ) that the TMP@Zn4L4 prepared in Example 1 has a high purity (>99%); it can be seen from the thermogravimetric spectrum ( Figure 2 ) that the TMP@Zn4L4 prepared in Example 1 has high thermal stability and can be stable up to 350 °C. It can be seen from the photothermal diagram ( Figure 4 ) that the light-blocking performance of TMP alone in nylon is weak, and the decomposition rate after 200 hours is 21.4% ( Figure 3 ); it can be seen from the photothermal diagram ( Figure 4 ) that the TMP@Zn4L4 prepared in Example 1 has obvious light-blocking performance in nylon, and the decomposition rate after 200 hours is only 5.1%.

Claims

1. A supramolecular cage-modified hindered amine light stabilizer, characterized in that: The hindered amine light stabilizer is distributed inside the cavity of the molecular cage with a hollow structure.

2. The supramolecular cage-modified hindered amine light stabilizer according to claim 1, characterized in that: The supramolecular cage is prepared by using divalent transition metal ions as nodes and tetrakis(4-aminophenyl)methane as a ligand.

3. The supramolecular cage-modified hindered amine light stabilizer according to claim 1, characterized in that: The hindered amine light stabilizer includes 2,2,6,6-tetramethylpiperidinol, 2,2,6,6-tetramethylpiperidinamine or 2,2,6,6-tetramethylpiperidone.

4. A method for preparing the supramolecular cage-modified hindered amine light stabilizer according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) preparing a solution containing a supramolecular cage; (2) preparing a solution containing a hindered amine light stabilizer; (3) slowly adding a solution containing a hindered amine light stabilizer into a solution containing a supramolecular cage to carry out a heating reaction, and then adding a precipitation solvent after the reaction is completed. The obtained precipitate is washed and dried to obtain a supramolecular cage-modified hindered amine light stabilizer.

5. The preparation method according to claim 4, characterized in that: In step (1), the preparation process of the solution containing the supramolecular cage is as follows: tetrakis(4-aminophenyl)methane and pyridine-2-carboxaldehyde are dissolved in an organic solvent to obtain a mixed solution, and then a divalent transition metal ion salt is slowly added, and the mixture is heated and stirred to obtain the solution.

6. The preparation method according to claim 5, characterized in that: The molar ratio of tetrakis(4-aminophenyl)methane, pyridine-2-carboxaldehyde and divalent transition metal ion salt is 1:3-4:1-2; the concentration of tetrakis(4-aminophenyl)methane in the mixed solution is 1-100 mM; the divalent transition metal ion salt is zinc trifluoromethanesulfonate; the slow addition speed is: 5-10 mL / min; the heating and stirring conditions are: reacting at 70±5°C for 2-24 hours.

7. The preparation method according to claim 4, characterized in that: In step (2), the concentration of the hindered amine light stabilizer in the solution containing the hindered amine light stabilizer is 1-50 mM.

8. The preparation method according to claim 4, characterized in that: In step (3), the speed of the slow addition is 1-3 mL / min; the heating reaction conditions are 70±5° C. for 1-10 h; and the precipitation solvent is an ether solvent.

9. Use of the supramolecular cage-modified hindered amine light stabilizer according to any one of claims 1 to 3 in polymer melt spinning.

10. The use according to claim 9, characterized in that: The polymers include nylon 6, nylon 66 and polyethylene terephthalate.

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