Antioxidant and preparation method thereof

Abstract

The invention belongs to the technical field of fine chemical engineering, and particularly relates to an antioxidant and a preparation method thereof. The antioxidant is prepared from the following components in parts by weight: 30 to 60 parts of a main antioxidant, 8 to 20 parts of an auxiliary antioxidant, 5 to 15 parts of modified tannic acid, 10 to 15 parts of a nucleating agent and 15 to 20 parts of a lubricating agent; the main antioxidant is a hindered phenol antioxidant, and the auxiliary antioxidant is a thioester or phosphite ester antioxidant. The modified tannic acid is compounded with a common antioxidant of a polymer, so that the oxidation induction period of the polymer can be prolonged, the yellow index of the polymer is obviously reduced, and the application of the tannic acid in the field of polymer antioxidants is further expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemical industry, and in particular relates to an antioxidant and a preparation method thereof. Background Art

[0002] Antioxidants are used to inhibit the oxidative degradation of polymers during manufacturing, processing and use. The demand for antioxidants has increased with the expansion of the production scale of rubber and plastic products. Currently, commonly used antioxidants include hindered phenols (such as 1010, 1076), phosphites (such as 168, 626) and thioethers (such as DSTDP, DLTDP). These varieties are widely praised and in high demand. However, as the polymer processing industry pursues high-performance and high-value-added products, the requirements for anti-oxidation and color improvement in resin processing are increasing, and the advantages and disadvantages of single antioxidants are becoming apparent. In view of the difficulty in developing new antioxidants, compounding with existing products to improve efficiency has become a research and development hotspot in recent years.

[0003] CN106336526A discloses a composite antioxidant. The patent adds color powder to the antioxidant and then adds it during the polymer processing. It is found that only a small amount of color powder added to the antioxidant can achieve long-term protection of the color of the polymer material. CN104356507A discloses a hindered phenol polypropylene composite antioxidant. The main antioxidant includes N,N-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hexanediamine, α-vitamin E and tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester; the auxiliary antioxidant is tris(2,4-di-tert-butylphenyl) phosphite; the composite antioxidant can better meet the requirements of various comprehensive properties of polypropylene, improve antioxidant performance and reduce costs.

[0004] The prior art discloses a method for adjusting the yellow index of an antioxidant by using a color powder and the antioxidant effect of tannic acid in the field of polymers. However, the natural color of tannic acid affects its function as an antioxidant to optimize the color index of polymers. Therefore, it is urgent to develop an antioxidant comprising modified tannic acid, thereby reducing the effect of the color of tannic acid itself on the color of polymers and expanding the application field of tannic acid as an oxidant. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, one of the objects of the present invention is to provide an antioxidant having good color stability and antioxidant properties.

[0006] One of the purposes of the present invention is achieved by the following technical solution:

[0007] An antioxidant, comprising the following components by weight: 30 to 60 parts of a primary antioxidant, 8 to 20 parts of an auxiliary antioxidant, 5 to 15 parts of modified tannic acid, 10 to 15 parts of a nucleating agent, and 15 to 20 parts of a lubricant;

[0008] The main antioxidant is a hindered phenol antioxidant, and the auxiliary antioxidant is a thioester or phosphite antioxidant;

[0009] The preparation process of the modified tannic acid comprises the following steps:

[0010] (1) 4-Hydroxy-7-N,N-diethylaminocoumarin, malononitrile, p-nitrobenzaldehyde and potassium hydrogen phthalate are added to water, reacted at 50-70° C. for 5-7 hours, and then treated to obtain intermediate 1;

[0011] (2) Intermediate 1 and N,N-dimethylformamide dimethyl acetal are mixed, reacted at 105-115° C. for 20-40 min, and then treated to obtain intermediate 2;

[0012] (3) adding intermediate 2 and iron powder to acetic acid, reacting for 12 to 18 hours, and then treating to obtain intermediate 3;

[0013] (4) adding the intermediate 3,4-fluoro-3-formaldehyde phenylboronic acid and magnesium sulfate to dichloromethane, reacting for 8 to 16 hours, and then treating to obtain a tannic acid modifier;

[0014] (5) Adding a tannic acid modifier, tannic acid and magnesium sulfate into water, stirring at room temperature for 12 to 16 hours, and obtaining the modified tannic acid.

[0015] The principle of preparing the modified tannic acid of the present invention is as follows: first, 4-hydroxy-7-N, N-diethylaminocoumarin, malononitrile, p-nitrobenzaldehyde and potassium hydrogen phthalate are subjected to a Knoevenagel condensation reaction to obtain an intermediate 1; then, DMF-DMA is used as a formylation reagent to react with a primary amine of the intermediate 1 to generate a corresponding amidine compound, namely, an intermediate 2; then, the intermediate 2 is reduced to an amine group by iron powder under acidic conditions to obtain an intermediate 3; then, the amine group of the intermediate 3 reacts with the aldehyde group of 4-fluoro-3-formylphenylboronic acid to obtain a Schiff base, namely, a tannic acid modifier; finally, the active functional group boric acid of the tannic acid modifier and the active functional group phenolic hydroxyl group of the tannic acid can generate the modified tannic acid under relatively mild reaction conditions.

[0016] Furthermore, the molar ratio of 4-hydroxy-7-N,N-diethylaminocoumarin, malononitrile, p-nitrobenzaldehyde and potassium hydrogen phthalate in step (1) is 1:(1-1.2):(1-1.2):(0.98-1).

[0017] Furthermore, in step (2), the molar ratio of the intermediate 1 to N,N-dimethylformamide dimethyl acetal is 1:(65-75).

[0018] Furthermore, in step (3), the molar ratio of the intermediate 2 to the iron powder is 1:(15-18).

[0019] Furthermore, in step (4), the molar ratio of the intermediate 3, 4-fluoro-3-formaldehyde phenylboronic acid and magnesium sulfate is 1: (1-1.2): (0.02-0.04).

[0020] Furthermore, in step (5), the molar ratio of tannic acid, tannic acid modifier and magnesium sulfate is 1:(4.1-4.5):(4.2-4.5).

[0021] Furthermore, the hindered phenol antioxidant is one of antioxidant 1010, antioxidant 1076 and antioxidant 736; the thioester is one of antioxidant DLTDP and antioxidant DTPDP; and the phosphite antioxidant is antioxidant 618.

[0022] Furthermore, the nucleating agent is one of HPN-20E and nucleating agent 713; the lubricant is one of zinc stearate and calcium stearate.

[0023] A second object of the present invention is to provide a method for preparing an antioxidant.

[0024] The second object of the present invention is achieved by adopting the following technical solution:

[0025] The method for preparing the above-mentioned antioxidant comprises the following steps: adding a primary antioxidant, an auxiliary antioxidant, modified tannic acid, a nucleating agent and a lubricant into a kneader and stirring for 30 minutes, then heating to 130-150° C., and continuing stirring for 45-60 minutes. After the blending is completed, the mixture is cooled to 20-45° C. for granulation to obtain the antioxidant.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The invention can increase the oxidation induction period of the polymer by compounding the modified tannic acid with a common antioxidant for the polymer. Meanwhile, the modified tannic acid can also reduce the influence of the color of the tannic acid itself on the color of the polymer, thereby significantly reducing the yellow index thereof, and further expanding the application of tannic acid in the field of polymer antioxidants. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart for preparing the modified tannic acid;

[0029] Figure 2 IR schematic diagram of the modified tannic acid of the present invention. DETAILED DESCRIPTION

[0030] Below, in conjunction with the accompanying drawings and specific embodiments, the present invention is further described. It should be noted that, under the premise of no conflict, the embodiments described below or the technical features can be arbitrarily combined to form new embodiments. The specific conditions not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, unless otherwise specified, are conventional products obtained through commercial channels.

[0031] Example 1

[0032] An antioxidant comprises the following components by weight: 45 parts of antioxidant 1010, 15 parts of antioxidant 618, 8 parts of modified tannic acid, 12 parts of nucleating agent 713, and 17 parts of zinc stearate.

[0033] The preparation process of the modified tannic acid is as follows Figure 1 As shown, the following steps are included:

[0034] (1) 4-Hydroxy-7-N,N-diethylaminocoumarin (0.1 mol), malononitrile (0.1 mol), p-nitrobenzaldehyde (0.1 mol) and potassium hydrogen phthalate (KHP, 98 mmol) were added to 150 mL of deionized water, stirred evenly and heated to 50°C for 6 h; the reaction solution was cooled to room temperature and filtered, the filter cake was collected (the filter cake was washed with deionized water during the filtration process) and dried, and then slurried with a mixed solvent (1 g of filter cake: 3 mL of mixed solvent, V 氯仿 :V 乙醇 =1:2) to obtain intermediate 1.

[0035] (2) Intermediate 1 (0.1 mol) and N,N-dimethylformamide dimethyl acetal (DMF-DMA, 7 mol) were reacted at 110° C. for 30 min; the reaction solution was filtered to collect the filter cake, which was washed with ethanol and dried during the filtration process. The filter cake was dissolved with chloroform and the solid was precipitated from the chloroform solution with ethanol to obtain Intermediate 2.

[0036] (3) Intermediate 2 (0.05 mol) was added to 100 mL of acetic acid, and then iron powder (0.8 mol) was added to react at 25°C for 16 h; the reaction solution was filtered through Celite (the filter cake was washed with ethyl acetate during filtration), the filtrate was collected and concentrated, and then the concentrate was diluted with water, and the aqueous phase was extracted with ethyl acetate, and then the ethyl acetate phase was washed with saturated brine, and the ethyl acetate phase was dried over sodium sulfate, concentrated, and passed through a column (eluent, petroleum ether: ethyl acetate = 10:1) to obtain intermediate 3. MS result of intermediate 3: [M+H] + m / z: 458.21, ESI-MS (m / z): 458.23.

[0037] (4) Intermediate 3 (0.1 mol), 4-fluoro-3-formaldehyde phenylboronic acid (0.11 mol), and magnesium sulfate (3 mmol) were added to 200 mL of dichloromethane and reacted at 28° C. for 12 h. The reaction solution was dried, concentrated, and column-filtered (1 wt % acetic acid was added to the eluent, and the eluent was petroleum ether:ethyl acetate = 7:1) to obtain a tannic acid modifier.

[0038] MS results of tannic acid modifier: [M+H] + m / z: 608.24, ESI-MS (m / z): 608.25; NMR results of tannic acid modifier: 1 H NMR (C 33 H 31 BFN5O5, 400MHz, DMSO-d6): δ8.69 (d, 2H), 7.78 (m, 1H), 7.65 (d, 1H), 7.42 (m, 1H), 7.38 (m, 3H), 7.15 (m, 1H), 6.93 (m, 1H), 6.68 (m, 1H), 6.49 (s, 1H), 4.25 (s, 1H), 3.36 (q, 4H), 2.99 (s, 6H), 1.12 (t, 6H).

[0039] (5) Add tannic acid modifier (42 mmol) and tannic acid (10 mmol) to a mixed solvent of 150 mL THF and 3 mL water, stir for 20 min, then add magnesium sulfate (43 mmol), and stir at room temperature for 14 h; concentrate the reaction solution, dilute the concentrated solution with ethanol, dialyze through a dialysis bag (molecular weight cutoff 3000D) to remove impurities with a molecular weight lower than 3000D, and concentrate and dry the solution in the dialysis bag to obtain modified tannic acid.

[0040] The IR results of the modified tannic acid are as follows: Figure 2 As shown in the figure: Compared with tannic acid, the absorption of the phenolic hydroxyl group of modified tannic acid (3600~3200cm -1 ) is weakened and at 2240cm -1 The characteristic peak of cyano group (from tannic acid modifier) ​​appears at , and the above results indicate that the modified tannic acid is successfully prepared by the present invention.

[0041] This embodiment also provides a method for preparing the above antioxidant, the process comprising the following steps:

[0042] Add antioxidant 1010, antioxidant 618, modified tannic acid, nucleating agent 713 and zinc stearate into a kneader and stir for 30 minutes. Then heat to 140°C and continue stirring for 52 minutes. After blending, transfer the mixed material to a storage tank through an insulated pipe, cool to 25°C and then transport to a granulator for granulation to obtain the antioxidant.

[0043] Example 2

[0044] An antioxidant comprises the following components by weight: 30 parts of antioxidant 1076, 8 parts of antioxidant DLTDP, 5 parts of modified tannic acid, 10 parts of nucleating agent HPN-20E, and 15 parts of calcium stearate.

[0045] The preparation process of the modified tannic acid comprises the following steps:

[0046] (1) 4-Hydroxy-7-N,N-diethylaminocoumarin (0.1 mol), malononitrile (0.11 mol), p-nitrobenzaldehyde (0.11 mol) and potassium hydrogen phthalate (KHP, 99 mmol) were added to 150 mL of deionized water, stirred evenly and heated to 70°C for 5 h; the reaction solution was cooled to room temperature and filtered, the filter cake was collected (the filter cake was washed with deionized water during the filtration process) and dried, and then slurried with a mixed solvent (1 g of filter cake: 3 mL of mixed solvent, V 氯仿 :V 乙醇 =1:2) to obtain intermediate 1;

[0047] (2) Intermediate 1 (0.1 mol) and N,N-dimethylformamide dimethyl acetal (7.5 mol) were reacted at 105° C. for 40 min; the reaction solution was filtered to collect the filter cake, and the filter cake was washed with ethanol during the filtration process, dried, and then recrystallized with a mixed solvent (the filter cake was dissolved with chloroform and then the solid was precipitated from the chloroform solution with ethanol) to obtain Intermediate 2;

[0048] (3) Intermediate 2 (0.05 mol) was added to 100 mL of acetic acid, and iron powder (0.75 mol) was added to react at 23° C. for 18 h; the reaction solution was filtered through Celite (the filter cake was washed with ethyl acetate during filtration), the filtrate was collected and concentrated, and the concentrate was diluted with water, and the aqueous phase was extracted with ethyl acetate, and the ethyl acetate phase was washed with saturated brine, and the ethyl acetate phase was dried over sodium sulfate, concentrated, and passed through a column (eluent, petroleum ether:ethyl acetate=10:1) to obtain intermediate 3. The MS results of intermediate 3 in this example are consistent with those shown in Example 1.

[0049] (4) Intermediate 3 (0.1 mol), 4-fluoro-3-formaldehyde phenylboronic acid (0.12 mol), and magnesium sulfate (2 mmol) were added to 200 mL of dichloromethane and reacted at 25° C. for 16 h; the reaction solution was dried, concentrated, and column-filtered (1 wt% acetic acid was added to the eluent, and the eluent was petroleum ether: ethyl acetate = 7:1) to obtain a tannic acid modifier. The MS and NMR results of the tannic acid modifier in this example were consistent with those shown in Example 1.

[0050] (5) Add tannic acid modifier (45 mmol) and tannic acid (10 mmol) to a mixed solvent of 150 mL THF and 3 mL water, stir for 20 min, then add magnesium sulfate (45 mmol), and stir at room temperature for 12 h; concentrate the reaction solution, dilute the concentrated solution with ethanol, dialyze through a dialysis bag (molecular weight cutoff 3000D) to remove impurities with a molecular weight lower than 3000D, and concentrate and dry the solution in the dialysis bag to obtain modified tannic acid.

[0051] The IR results of the modified tannic acid in this example are consistent with those shown in Example 1.

[0052] The preparation process of the antioxidant comprises the following steps: adding antioxidant 1076, antioxidant DLTDP, modified tannic acid, nucleating agent HPN-20E and calcium stearate into a kneader and stirring for 30 minutes, then heating to 130° C. and continuing stirring for 60 minutes. After the blending is completed, the mixed material is transferred to a storage tank through an insulation pipe, cooled to 35° C. and then transported to a granulator for granulation to obtain the antioxidant.

[0053] Example 3

[0054] An antioxidant comprises the following components by weight: 60 parts of antioxidant 736, 20 parts of antioxidant DTPDP, 15 parts of modified tannic acid, 15 parts of nucleating agent 713, and 20 parts of zinc stearate.

[0055] The preparation process of the modified tannic acid comprises the following steps:

[0056] (1) 4-Hydroxy-7-N,N-diethylaminocoumarin (0.1 mol), malononitrile (0.12 mol), p-nitrobenzaldehyde (0.12 mol) and potassium hydrogen phthalate (KHP, 0.1 mol) were added to 150 mL of deionized water, stirred evenly and then heated to 50°C for 7 h. The reaction solution was cooled to room temperature and filtered, the filter cake was collected (the filter cake was washed with deionized water during the filtration process) and dried, and then slurried with a mixed solvent (1 g of filter cake: 3 mL of mixed solvent, V 氯仿 :V 乙醇 =1:2) to obtain intermediate 1;

[0057] (2) Intermediate 1 (0.1 mol) and N,N-dimethylformamide dimethyl acetal (6.5 mol) were reacted at 115° C. for 20 min; the reaction solution was filtered to collect the filter cake, and the filter cake was washed with ethanol during the filtration process, dried, and then recrystallized with a mixed solvent (the filter cake was dissolved with chloroform and then the solid was precipitated from the chloroform solution with ethanol) to obtain Intermediate 2;

[0058] (3) Intermediate 2 (0.05 mol) was added to 100 mL of acetic acid, and iron powder (0.9 mol) was added to react at 28° C. for 12 h; the reaction solution was filtered through Celite (the filter cake was washed with ethyl acetate during filtration), the filtrate was collected and concentrated, and the concentrate was diluted with water, and the aqueous phase was extracted with ethyl acetate, and the ethyl acetate phase was washed with saturated brine, and the ethyl acetate phase was dried over sodium sulfate, concentrated, and passed through a column (eluent, petroleum ether:ethyl acetate = 10:1) to obtain Intermediate 3.

[0059] The MS results of intermediate 3 in this example are consistent with those shown in Example 1.

[0060] (4) Intermediate 3 (0.1 mol), 4-fluoro-3-formaldehyde phenylboronic acid (0.1 mol), and magnesium sulfate (4 mmol) were added to 200 mL of dichloromethane and reacted at 30° C. for 8 h; the reaction solution was dried, concentrated, and column-filtered (1 wt% acetic acid was added to the eluent, and the eluent was petroleum ether:ethyl acetate = 7:1) to obtain a tannic acid modifier. The MS and NMR results of the tannic acid modifier in this example were consistent with those shown in Example 1.

[0061] (5) Add tannic acid modifier (41 mmol) and tannic acid (10 mmol) to a mixed solvent of 150 mL THF and 3 mL water, stir for 20 min, then add magnesium sulfate (42 mmol), and stir at room temperature for 16 h; concentrate the reaction solution, dilute the concentrated solution with ethanol, dialyze through a dialysis bag (molecular weight cutoff 3000D) to remove impurities with a molecular weight lower than 3000D, and concentrate the solution in the dialysis bag and dry it to obtain modified tannic acid.

[0062] The IR results of the modified tannic acid in this example are consistent with those shown in Example 1.

[0063] The preparation process of the antioxidant comprises the following steps: adding antioxidant 736, antioxidant DTPDP, modified tannic acid, nucleating agent 713 and zinc stearate into a kneader and stirring for 30 minutes, then heating to 150° C. and continuing stirring for 45 minutes. After the blending is completed, the mixed material is transferred to a storage tank through an insulation pipe, cooled to 35° C. and then transported to a granulator for granulation to obtain the antioxidant.

[0064] Comparative Example 1

[0065] An antioxidant, which is different from Example 1 in that the modified tannic acid is omitted.

[0066] Comparative Example 2

[0067] An antioxidant, which is different from Example 1 in that the modified tannic acid is replaced by an equal amount of tannic acid.

[0068] Test example

[0069] The antioxidant properties of the antioxidants prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were measured. The oxidation induction period of the composite antioxidant was measured by DSC method, and the yellowness index of the composite antioxidant was measured according to GB 2409-1980. The results are shown in Table 1:

[0070] Table 1 Antioxidant properties of antioxidants

[0071]

[0072] As can be seen from Table 1, compared with Comparative Examples 1 to 2 in which the modified tannic acid is omitted, the technical solutions of Examples 1 to 3 increase the oxidation induction period, which indicates that the modified tannic acid can optimize the oxidation performance of the polymer; compared with Comparative Example 3, the technical solutions of Examples 1 to 3 increase the oxidation induction period, and the yellowness index is significantly reduced, which indicates that the modified tannic acid, i.e., the modified tannic acid, can optimize the yellowness index of the polymer.

[0073] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. An antioxidant, characterized in that The composition comprises the following components by weight: 30 to 60 parts of a primary antioxidant, 8 to 20 parts of an auxiliary antioxidant, 5 to 15 parts of modified tannic acid, 10 to 15 parts of a nucleating agent, and 15 to 20 parts of a lubricant; The main antioxidant is a hindered phenol antioxidant, and the auxiliary antioxidant is a thioester or phosphite antioxidant; The preparation process of the modified tannic acid comprises the following steps: (1) 4-Hydroxy-7-N,N-diethylaminocoumarin, malononitrile, p-nitrobenzaldehyde and potassium hydrogen phthalate are added to water, reacted at 50-70° C. for 5-7 hours, and then treated to obtain intermediate 1; (2) Intermediate 1 and N,N-dimethylformamide dimethyl acetal are mixed, reacted at 105-115° C. for 20-40 min, and then treated to obtain intermediate 2; (3) adding intermediate 2 and iron powder to acetic acid, reacting for 12 to 18 hours, and then treating to obtain intermediate 3; (4) adding the intermediate 3,4-fluoro-3-formaldehyde phenylboronic acid and magnesium sulfate to dichloromethane, reacting for 8 to 16 hours, and then treating to obtain a tannic acid modifier; (5) Adding a tannic acid modifier, tannic acid and magnesium sulfate into water, stirring for 12 to 16 hours, and obtaining the modified tannic acid through treatment.

2. The antioxidant according to claim 1, characterized in that The molar ratio of 4-hydroxy-7-N,N-diethylaminocoumarin, malononitrile, p-nitrobenzaldehyde and potassium hydrogen phthalate in step (1) is 1:(1-1.2):(1-1.2):(0.98-1).

3. The antioxidant according to claim 1, characterized in that The molar ratio of the intermediate 1 to N,N-dimethylformamide dimethyl acetal in step (2) is 1:(65-75).

4. The antioxidant according to claim 1, characterized in that In step (3), the molar ratio of the intermediate 2 to the iron powder is 1:(15-18).

5. The antioxidant according to claim 1, characterized in that In step (4), the molar ratio of the intermediate 3, 4-fluoro-3-formaldehyde phenylboronic acid and magnesium sulfate is 1: (1-1.2): (0.02-0.04).

6. The antioxidant according to claim 1, characterized in that The molar ratio of tannic acid, tannic acid modifier and magnesium sulfate in step (5) is 1:(4.1-4.5):(4.2-4.5).

7. The antioxidant according to claim 1, characterized in that The hindered phenol antioxidant is one of antioxidant 1010, antioxidant 1076 and antioxidant 736; the thioester antioxidant is one of antioxidant DLTDP and antioxidant DTPDP; and the phosphite antioxidant is antioxidant 618.

8. The antioxidant according to claim 1, characterized in that The nucleating agent is one of HPN-20E and nucleating agent 713; the lubricant is one of zinc stearate and calcium stearate.

9. The method for preparing the antioxidant according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: adding a primary antioxidant, an auxiliary antioxidant, modified tannic acid, a nucleating agent and a lubricant into a kneader and stirring for 30 minutes, then heating the mixture to 130-150° C., and continuing stirring for 45-60 minutes. After the blending is completed, cooling the mixture to 20-45° C. for granulation to obtain the antioxidant.

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