Process for the preparation of an anti-aging agent and its use in plastics

Abstract

The application relates to the technical field of anti-aging agents, and discloses a preparation method of an anti-aging agent and application of the anti-aging agent in plastics, wherein the anti-aging agent contains a styrene group, can be well melt-grafted with polyolefins such as polypropylene under the action of an initiator such as dibenzoyl peroxide or dicumyl peroxide, has little influence on the mechanical strength of the polyolefin plastics, and can avoid the problem that physical blending has a great influence on the mechanical strength and use performance of the plastics. Meanwhile, the anti-aging agent contains a phenol group triazine structure, has unique ultraviolet absorption effect, and contains a hindered amine structure, can inhibit the photo-oxidation degradation reaction of the polyolefin plastics through various ways such as capturing free radicals and decomposing hydrogen peroxide, the plastics keep high tensile strength through xenon lamp irradiation accelerated aging experiment, and excellent thermal-oxidative aging resistance and ultraviolet irradiation aging resistance are shown.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-aging agents, in particular to a preparation method of an anti-aging agent and application of the anti-aging agent in plastics. BACKGROUND

[0002] Polyolefin plastics mainly include polyethylene, polyvinyl chloride, polypropylene, polystyrene, etc., and have good chemical resistance, electrical insulation, high strength mechanical properties, and are widely used. However, the heat-oxidative aging resistance and ultraviolet aging resistance of polyolefin plastics such as polyvinyl chloride and polypropylene are poor, and their performance will be affected after long-term heat treatment or light exposure.

[0003] Antioxidants, ultraviolet absorbers, etc. are usually added during the processing of polyolefin to improve the heat-oxidative aging resistance and ultraviolet aging resistance of polyolefin. The current anti-aging agents mainly include phosphite antioxidants, hindered amine light stabilizers, benzophenone ultraviolet absorbers, and triazine ultraviolet absorbers. Developing new dual-function anti-aging agents for application in polyolefin plastics is a research hotspot.

[0004] Patent No. CN109134928B discloses an N-substituted triazine hindered amine light stabilizer, which can be used as a stabilizer and an organic substance flame retardant for organic substances sensitive to degradation caused by light, heat or oxidation. Patent No. CN110724165B discloses a hexahydrotriazine compound with heat-oxidative aging resistance, which contains a large number of benzene rings, hindered phenols, triazine ring structures, etc. in its molecular structure, and can improve the aging resistance of polyvinyl chloride. However, directly physically blending antioxidants, ultraviolet absorbers, anti-aging agents with polypropylene, polyvinyl chloride and other polyolefin plastics will result in poor compatibility of the anti-aging agents with the matrix, affecting the mechanical strength and performance of the plastics, and the antioxidants and anti-aging agents may be precipitated and migrated. SUMMARY

[0005] The present application solves the following technical problems: a preparation method of a dual-function anti-aging agent is provided, which solves the problem of poor anti-aging performance of polypropylene and other polyolefin plastics.

[0006] The present application provides the following technical solutions:

[0007] A preparation method of an anti-aging agent, the structural formula of the anti-aging agent is shown as formula (I);

[0008]

[0009] The preparation method is as follows:

[0010] S1, adding solvent, 2-amino-4, 6-dichlorotriazine, 4-vinylbenzoyl chloride and catalyst pyridine to the flask at-5 to 0℃, reacting for 3-6h at 15-25℃, after reaction, concentrated by rotary evaporation, washed with n-hexane, dried to obtain intermediate 1;

[0011] S2, adding chloroform solvent, intermediate 1, 2, 4-dihydroxytoluene, catalyst aluminum trichloride to the flask, after reaction, concentrated by rotary evaporation, washed with saturated sodium chloride solution, acetone in turn, dried to obtain intermediate 2;

[0012] S3, adding n-butanol solvent, formaldehyde aqueous solution, intermediate 2 and 2, 2, 6, 6-tetramethylpiperidinamine to the flask, after reaction, concentrated by rotary evaporation, adding water, ethyl acetate, separating by extraction, concentrating the organic layer by rotary evaporation, washing with acetone, recrystallizing the product with a mixed solution of ethanol and ethyl acetate in a volume ratio of 1:1 to obtain the anti-aging agent.

[0013] Further, the solvent in S1 includes ethyl acetate, 1, 4-dioxane, acetone, tetrahydrofuran.

[0014] Further, the ratio of 2-amino-4, 6-dichlorotriazine, 4-vinylbenzoyl chloride and pyridine in S1 is 1mol:(2-2.2)mol:(2-2.4)mol.

[0015] Further, the ratio of intermediate 1, 2, 4-dihydroxytoluene, aluminum trichloride in S2 is 1mol:(3.6-4.8)mol:(3.5-4.5)mol.

[0016] Further, the reaction temperature in S2 is 20-35℃, and the reaction time is 6-12h.

[0017] Further, the ratio of formaldehyde, intermediate 2 and 2, 2, 6, 6-tetramethylpiperidinamine in S3 is (6-7.2):1mol:(2.6-3.5)mol.

[0018] Further, the reaction temperature in S3 is 85-100℃, and the reaction time is 10-18h.

[0019] Further, the polyolefin, the anti-aging agent, the initiator dibenzoyl peroxide or dicumyl peroxide are placed in a twin-screw extruder for melt grafting, the temperature of each section of the extruder is 180-210℃, the screw rotation speed is 100-150r / min, extruded, then the material is dissolved in xylene, precipitated by adding acetone, filtered, washed with acetone, dried to obtain the anti-aging plastic.

[0020] Further, the ratio of polyolefin, anti-aging agent, initiator is 1g:(1-6)mg:(0.3-3)mg.

[0021] Further, the polyolefins include polyethylene, polyvinyl chloride, polypropylene, polystyrene, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene-styrene copolymer.

[0022] The present application has the following technical effects:

[0023] The present application uses 2-amino-4,6-dichloro-s-triazine, 4-vinyl benzoyl chloride, 2,2,6,6-tetramethylpiperidine amine, 2,4-dihydroxytoluene, etc. as the raw materials, and through esterification reaction, Friedel-Crafts reaction and Mannich reaction, a novel anti-aging agent is prepared, which has the advantages of novel and efficient preparation method, simple operation, high product yield and novel structure. The methyl group is introduced at the 3rd position of the benzene ring using 2,4-dihydroxytoluene as the raw material, and the intermediate 2 is obtained, which can avoid the reaction between 2,2,6,6-tetramethylpiperidine amine and the carbon atom at the 3rd position of the benzene ring in the subsequent reaction, and can reduce the complexity of the reaction system, so that the anti-aging agent product with high yield is obtained.

[0024] The anti-aging agent prepared by the present application contains a styryl group, which can be well melt-grafted with polyolefins such as polypropylene and polyethylene under the action of initiator dibenzoyl peroxide or dicumyl peroxide, has little effect on the mechanical strength of polyolefin plastics such as polypropylene and polyethylene, and can avoid the problem that physical blending has a great influence on the mechanical strength and use performance of polyolefin plastics such as polypropylene and polyethylene. Meanwhile, the phenolic triazine structure contained in the anti-aging agent has a unique ultraviolet absorption effect, and contains a hindered amine structure, which can inhibit the photo-oxidation degradation reaction of plastics such as polypropylene and polyethylene through multiple ways such as capturing free radicals and decomposing hydroperoxide. After xenon lamp irradiation accelerated aging test, the plastics such as polypropylene and polyethylene maintain high tensile strength, and exhibit excellent thermal-oxidative aging resistance and ultraviolet radiation aging resistance. The anti-aging agent prepared by the present application has a broad application prospect in the field of polyolefin plastics. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the preparation route of the anti-aging agent.

[0026] Figure 2 is the infrared spectrum of the anti-aging agent. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] The polyolefin, anti-aging agent, initiator dibenzoyl peroxide or dicumyl peroxide are placed in a twin-screw extruder in a ratio of 1 g:(1-6) mg:(0.3-3) mg for melt grafting, wherein the polyolefin includes polyethylene, polyvinyl chloride, polypropylene, polystyrene, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene-styrene copolymer; the temperature of each section of the extruder is 180-210°C, the screw rotation speed is 100-150 r / min, and the material is extruded, then dissolved in xylene, precipitated by adding acetone, filtered, washed with acetone, and dried to obtain the anti-aging plastic.

[0029] Example 1

[0030] A flask is added with 20 mL of acetone solvent, 6 mmol of 2-amino-4,6-dichlorotriazine, 12 mmol of 4-vinylbenzoyl chloride, and 12 mmol of catalyst pyridine at 0°C, and reacted at 25°C for 3 h. After the reaction, rotary evaporation is performed for concentration, n-hexane washing, and drying to obtain intermediate 1. Theoretical yield 1.77 g (6 mmol), actual yield 1.47 g, yield 83.1%.

[0031] A flask is added with 10 mL of chloroform solvent, 4 mmol of intermediate 1, 14.4 mmol of 2,4-dihydroxytoluene, and 14 mmol of catalyst aluminum chloride at 25°C, and reacted for 10 h. After the reaction, rotary evaporation is performed for concentration, washing with saturated sodium chloride solution and acetone in sequence, and drying to obtain intermediate 2. Theoretical yield 1.88 g (4 mmol), actual yield 1.70 g, yield 90.4%.

[0032] A flask is added with 10 mL of n-butanol solvent, an aqueous solution containing 24 mmol of formaldehyde, 4 mmol of intermediate 2, and 10.4 mmol of 2,2,6,6-tetramethylpiperidinamine at 100°C, and reacted for 10 h. After the reaction, rotary evaporation is performed for concentration, water is added, ethyl acetate is extracted and separated, the organic layer is rotary evaporated for concentration, acetone is washed, and the product is recrystallized with a mixed solution of ethanol and ethyl acetate in a volume ratio of 1:1 to obtain the anti-aging agent. Theoretical yield 3.11 g (4 mmol), actual yield 1.81 g, yield 58.2%.

[0033] Description Figure 2 The infrared spectrum of the anti-aging agent shows that 3384 cm -1 is the absorption peak of the secondary amine bond N-H; 1561 cm -1 and 1492 cm -1 are the absorption peaks of the C=N bond and the C=C bond in the triazine ring, respectively; 1361 cm -1 and 1198 cm -1 are the out-of-plane vibration peak and the contraction vibration peak of the phenolic hydroxyl group, respectively.

[0034] Example 2

[0035] Into a flask, 25 mL of ethyl acetate solvent, 6 mmol of 2-amino-4,6-dichloro-s-triazine, 12.6 mmol of 4-vinylbenzoyl chloride, and 13 mmol of a catalyst pyridine were added at -5°C, and reacted for 6 h at 15°C, and after the reaction, concentrated by rotary evaporation, washed with n-hexane, and dried to obtain an intermediate 1. Theoretical yield 1.77 g (6 mmol), actual yield 1.64 g, yield 92.7%.

[0036] Into a flask, 10 mL of chloroform solvent, 4 mmol of the intermediate 1, 16.8 mmol of 2,4-dihydroxytoluene, and 16 mmol of a catalyst aluminum chloride were added, and reacted for 6 h at 35°C, and after the reaction, concentrated by rotary evaporation, sequentially washed with a saturated sodium chloride solution and acetone, and dried to obtain an intermediate 2. Theoretical yield 1.88 g (4 mmol), actual yield 1.79 g, yield 95.2%.

[0037] Into a flask, 15 mL of n-butanol solvent, an aqueous solution containing 26.5 mmol of formaldehyde, 4 mmol of the intermediate 2, and 12.5 mmol of 2,2,6,6-tetramethylpiperidine amine were added, and reacted for 12 h at 90°C, and after the reaction, concentrated by rotary evaporation, water was added, and extraction was performed using ethyl acetate, the organic layer was concentrated by rotary evaporation, washed with acetone, and the product was recrystallized using a mixed solution of ethanol and ethyl acetate in a volume ratio of 1:1 to obtain an anti-aging agent. Theoretical yield 3.11 g (4 mmol), actual yield 2.19 g, yield 70.4%.

[0038] Example 3

[0039] Into a flask, 30 mL of tetrahydrofuran solvent, 6 mmol of 2-amino-4,6-dichloro-s-triazine, 13.2 mmol of 4-vinylbenzoyl chloride, and 14.4 mmol of a catalyst pyridine were added at 0°C, and reacted for 4 h at 20°C, and after the reaction, concentrated by rotary evaporation, washed with n-hexane, and dried to obtain an intermediate 1. Theoretical yield 1.77 g (6 mmol), actual yield 1.58 g, yield 89.3%.

[0040] Into a flask, 15 mL of chloroform solvent, 4 mmol of the intermediate 1, 19.2 mmol of 2,4-dihydroxytoluene, and 18 mmol of a catalyst aluminum chloride were added, and reacted for 12 h at 20°C, and after the reaction, concentrated by rotary evaporation, sequentially washed with a saturated sodium chloride solution and acetone, and dried to obtain an intermediate 2. Theoretical yield 1.88 g (4 mmol), actual yield 1.81 g, yield 96.3%.

[0041] Into a flask was added 20 mL of n-butanol solvent, an aqueous solution containing 28.8 mmol of formaldehyde, 4 mmol of intermediate 2, and 14 mmol of 2,2,6,6-tetramethylpiperidinamine, and the reaction was carried out at 85°C for 18 h. After the reaction, the mixture was concentrated by rotary evaporation, water was added, and the mixture was extracted with ethyl acetate. The organic layer was concentrated by rotary evaporation, washed with acetone, and recrystallized from a mixture of ethanol and ethyl acetate (1:1 by volume) to obtain the anti-aging agent. The theoretical yield was 3.11 g (4 mmol), and the actual yield was 2.09 g, with a yield of 67.2%.

[0042] Example 4

[0043] Into a twin-screw extruder were placed 100 g of a polypropylene resin, 0.1 g of the anti-aging agent (prepared in the same manner as in Example 2), and 0.03 g of the initiator dicumyl peroxide, and the mixture was melt-grafted at a temperature of 180, 195, 210, 210, and 210°C in the first to fifth stages of the extruder, respectively, at a screw rotation speed of 120 r / min. The mixture was then extruded, dissolved in xylene, precipitated with acetone, filtered, washed with acetone, and dried to obtain an anti-aging polypropylene plastic.

[0044] Example 5

[0045] In this example, the difference from Example 4 is that the initiator was 0.03 g of dibenzoyl peroxide, and an anti-aging polypropylene plastic was obtained.

[0046] Example 6

[0047] In this example, the difference from Example 4 is that the amount of the anti-aging agent was 0.4 g, and the amount of the initiator dicumyl peroxide was 0.17 g, and an anti-aging polypropylene plastic was obtained.

[0048] Example 7

[0049] In this example, the difference from Example 4 is that the amount of the anti-aging agent was 0.6 g, and the amount of the initiator dicumyl peroxide was 0.3 g, and an anti-aging polypropylene plastic was obtained.

[0050] Comparative Example 1 was a pure polypropylene resin.

[0051] Comparative Example 2

[0052] Into a twin-screw extruder were placed 100 g of a polypropylene resin and 0.1 g of the anti-aging agent (prepared in the same manner as in Example 2), and the mixture was melt-blended at a temperature of 180, 195, 210, 210, and 210°C in the first to fifth stages of the extruder, respectively, at a screw rotation speed of 120 r / min. The mixture was then extruded to obtain a polypropylene plastic.

[0053] Comparative Example 3

[0054] 100 g of polypropylene resin, 0.1 g of 2,2,6,6-tetramethylpiperidine amine were placed in a twin-screw extruder for melt blending, the temperatures of the extruder 1-5 segments were 180, 195, 210, 210, 210 ℃ respectively, the screw rotation speed was 120 r / min, and extrusion was performed to obtain polypropylene plastic.

[0055] The polypropylene plastics of Examples 4-7 and Comparative Examples 2-3, and the pure polypropylene resin of Comparative Example 1 were respectively placed in a flat vulcanizing machine, 10 MPa, 200 ℃, and molded for 6 min; according to the method of GB / T1622.2-2014, xenon lamp aging test was performed in an accelerated aging test box, the xenon lamp power was controlled at 600 W, the temperature was 65 ℃, the relative humidity was 65%, and the aging time was 0, 24 h, 48 h, 96 h, 192 h, and 384 h, respectively.

[0056] The tensile properties of the polypropylene plastics were tested according to the method of GB / T 1040.2-2006.

[0057]

[0058]

[0059] Examples 4 and 5 were respectively melt-grafted with the prepared anti-aging agent and polypropylene using dibenzoyl peroxide or dicumyl peroxide, and compared with the tensile strength (36.7 MPa) of the pure polypropylene of Comparative Example 1, the tensile strengths of Examples 4 and 5 had almost no difference, indicating that the anti-aging agent had no effect on the mechanical properties of polypropylene after grafting. Meanwhile, the phenolic triazine structure contained in the anti-aging agent has a unique ultraviolet absorption effect, and contains a hindered amine structure, which can inhibit the polypropylene photo-oxidation degradation reaction through multiple pathways such as capturing free radicals and decomposing hydroperoxide, and after 384 h of xenon lamp ultraviolet irradiation, the tensile strength retention rate reaches more than 96%.

[0060] In Examples 6 and 7, as the amount of anti-aging agent increases, the initial tensile strength of polypropylene (0 h of xenon lamp irradiation) has a decreasing trend, but after xenon lamp ultraviolet irradiation, the retention rate gradually increases, and the highest reaches 97.7%.

[0061] Comparative Example 1 is pure polypropylene, the initial tensile strength is 36.7 MPa, after 384 h of xenon lamp ultraviolet irradiation, the tensile strength is 25.1 MPa, and the retention rate is only 68.4%, which is the worst anti-aging performance.

[0062] Comparative Example 2 The prepared anti-aging agent was physically blended with polypropylene, and the initial tensile strength of the polypropylene was 32.7 MPa, which was significantly lower than that of Example 3 (36.4 MPa), possibly because the anti-aging agent was less compatible with the polypropylene, and the physical blending affected the mechanical properties of the polypropylene plastic

[0063] Comparative Example 3 2,2,6,6-tetramethylpiperidine amine was added as a light stabilizer, which did not contain the anti-ultraviolet structure of the phenolic triazine, and the anti-ultraviolet aging performance was poor. After 384 h of xenon lamp ultraviolet irradiation, the tensile strength of the polypropylene plastic was 28.6 MPa, and the retention rate was only 81.2%.

[0064] Example 8

[0065] 100 g of polyethylene resin, 0.4 g of anti-aging agent (the preparation method was the same as that of Example 2), and 0.17 g of initiator dicumyl peroxide were placed in a twin-screw extruder for melt grafting. The temperatures of the 1-5 sections of the extruder were 180, 190, 205, 205, and 200°C, respectively, and the screw rotation speed was 100 r / min. The material was extruded, then dissolved in xylene, and precipitated by adding acetone. After filtration and acetone washing, the material was dried to obtain an anti-aging polyethylene plastic.

[0066] Comparative Example 4

[0067] 100 g of polyethylene resin, 0.4 g of anti-aging agent (the preparation method was the same as that of Example 2), were placed in a twin-screw extruder for melt grafting. The temperatures of the 1-5 sections of the extruder were 180, 190, 205, 205, and 200°C, respectively, and the screw rotation speed was 100 r / min. The material was extruded to obtain a polyethylene plastic.

[0068] Comparative Example 5 was pure polyethylene resin.

[0069] The polyethylene plastics of Example 8 and Comparative Example 4, and the pure polyethylene resin of Comparative Example 5 were respectively placed in a flat vulcanizing machine and molded at 10 MPa and 200°C for 5 min. According to the method of GB / T 1622.2-2014, xenon lamp aging experiments were carried out in an accelerated aging test box, with a xenon lamp power of 600 W, a temperature of 65°C, a relative humidity of 65%, and aging times of 0, 24 h, 48 h, 96 h, 192 h, and 384 h, respectively.

[0070] The tensile properties of the polyethylene plastics were tested according to the method of GB / T 1040.2-2006.

[0071]

[0072] Example 8 melt grafted polyethylene resin with anti-aging agent, the polyethylene plastic was subjected to 384 hours of xenon lamp UV irradiation, and the tensile strength retention rate of the polyethylene plastic reached 96.9%.

[0073] Comparative Example 4 physically blended anti-aging agent with polyethylene resin, and the initial tensile strength of the polyethylene plastic was only 27.1 MPa.

[0074] Comparative Example 5 was pure polyethylene resin, and the tensile strength retention rate was only 70.2% after 384 hours of xenon lamp UV irradiation.

Claims

1. A method for preparing an anti-aging agent, characterized by, The structural formula of the anti-aging agent is shown as formula (I); Formula (I); The preparation method is: S1, adding solvent, 2-amino-4, 6-dichlorotriazine, 4-vinyl benzoyl chloride and catalyst pyridine into a flask at-5 to 0℃, reacting for 3-6h at 15-25℃, concentrating after reaction, washing with n-hexane, drying to obtain intermediate 1; S2, adding chloroform solvent, intermediate 1, 2, 4-dihydroxytoluene and catalyst aluminum chloride into a flask, concentrating after reaction, washing with saturated sodium chloride solution and acetone in sequence, drying to obtain intermediate 2; S3, adding n-butanol solvent, formaldehyde aqueous solution, intermediate 2 and 2, 2, 6, 6-tetramethylpiperidinamine into a flask, concentrating after reaction, adding water and ethyl acetate, separating by extraction, concentrating the organic layer, washing with acetone, recrystallizing the product with a mixed solution of ethanol and ethyl acetate in a volume ratio of 1:1 to obtain the anti-aging agent.

2. The method of claim 1, wherein the anti-aging agent is prepared by the steps of: The solvent in S1 is selected from ethyl acetate, 1, 4-dioxane, acetone and tetrahydrofuran.

3. The method of claim 1, wherein the anti-aging agent is prepared by the steps of: The ratio of 2-amino-4, 6-dichlorotriazine, 4-vinyl benzoyl chloride and pyridine in S1 is 1mol:(2-2.2)mol:(2-2.4)mol.

4. The method of claim 1, wherein the anti-aging agent is prepared by the steps of: The ratio of intermediate 1, 2, 4-dihydroxytoluene and aluminum chloride in S2 is 1mol:(3.6-4.8)mol:(3.5-4.5)mol.

5. The method for preparing the anti-aging agent according to claim 1, characterized in that, The reaction temperature in S2 is 20-35℃, and the reaction time is 6-12h.

6. The method of claim 1, wherein the anti-aging agent is prepared by the steps of: The ratio of formaldehyde, intermediate 2 and 2, 2, 6, 6-tetramethylpiperidinamine in S3 is (6-7.2):1mol:(2.6-3.5)mol.

7. The method for preparing the anti-aging agent according to claim 1, characterized in that, The reaction temperature in S3 is 85-100℃, and the reaction time is 10-18h.

8. Use of an anti-aging agent prepared according to the process of any one of claims 1 to 7 in plastics, characterized in that: The polyolefin, the anti-aging agent and the initiator peroxide dibenzoyl or dicumyl peroxide are placed in a twin-screw extruder for melt grafting, the temperature of each section of the extruder is 180-210℃, the screw rotation speed is 100-150r / min, the material is extruded, then dissolved in xylene, precipitated by adding acetone, filtered, washed with acetone and dried to obtain the anti-aging plastic.

9. Use of an anti-aging agent in plastics according to claim 8, characterized in that: The ratio of the polyolefin, the anti-aging agent and the initiator is 1g:(1-6)mg:(0.3-3)mg.

10. Use of an anti-aging agent in plastics according to claim 8, characterized in that: The polyolefin is selected from polyethylene, polyvinyl chloride, polypropylene, polystyrene, ethylene-vinyl acetate copolymer and acrylonitrile-butadiene-styrene copolymer.

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