Aqueous emulsion antioxidant, preparation method therefor, and use thereof

Abstract

The present invention provides an efficient aqueous emulsion antioxidant, a preparation method therefor, and a use thereof. The efficient aqueous emulsion antioxidant comprises an oil-soluble antioxidant, an emulsifier, a defoaming agent, and water, wherein the emulsifier is an anionic surfactant, a nonionic surfactant, and / or a colloid-protecting composition. The beneficial effects of the present invention lie in: the efficient aqueous emulsion antioxidant of the present invention has good compatibility with an emulsion-polymerized polymer by utilizing the synergistic effect of the emulsifier, the anti-aging performance is good, the effective utilization rate of the emulsion antioxidant is high, the stability is high, and the emulsion antioxidant can be stored for a long time. The efficient aqueous emulsion antioxidant of the present invention is an environmentally friendly aqueous product, avoids dust pollution and explosion risks caused by direct addition of a solid antioxidant, the problem of conventional liquid antioxidants having poor compatibility with emulsion-polymerized polymer systems, and the resource utilization rate is improved.

Description

Aqueous emulsion antioxidant and its preparation method and application Technical Field

[0001] The invention belongs to the technical field of fine chemicals, and particularly relates to an aqueous emulsion antioxidant and a preparation method and application thereof. Background Art

[0002] Emulsion polymerization involves dispersing monomers in water with the aid of an emulsifier and mechanical stirring to form an emulsion, followed by the addition of an initiator to initiate polymerization. Polymers prepared via emulsion polymerization primarily include latex and its products (including but not limited to natural rubber latex, nitrile latex, styrene-butadiene latex, styrene-butadiene-pyrrolidone latex, chloroprene latex, isoprene latex, and natural latex), emulsion-polymerized rubber (including but not limited to latex styrene-butadiene rubber, nitrile rubber, and chloroprene rubber), and other polymers containing specific functional groups (including but not limited to ABS, ASA, MBS, polymethacrylates and their copolymers, polyvinyl chloride, polyvinyl acetate and their copolymers, and polytetrafluoroethylene). Millions of tons of polymers are produced annually worldwide through emulsion polymerization, making emulsion polymerization increasingly important for polymer production.

[0003] However, during the synthesis, processing, transportation, storage, and use of emulsion polymers, they are inevitably exposed to oxygen, light, heat, and mechanical stress, which can generate free radicals and cause degradation. Therefore, antioxidants are often added before use. Conventional antioxidants are mostly oil-soluble, with poor compatibility with water and low effective utilization rates. Furthermore, with increasing environmental protection requirements, water-based antioxidants are increasingly favored by society.

[0004] Currently, commercially available water-based antioxidants are primarily formulated with solid antioxidants, limiting the application of water-based liquid antioxidants. Therefore, developing a process for preparing water-based antioxidants that can utilize both solid and liquid antioxidants is imperative. Furthermore, the relatively large particle size of water-based antioxidants used in emulsion polymerization, coupled with the low antioxidant dosage of a few thousandths, results in low antioxidant coverage, hindering the ability of the water-based antioxidant to penetrate the polymer micelles and provide targeted protection, severely impacting anti-aging effectiveness. Therefore, developing an emulsion antioxidant with a small particle size and rapid migration rate that can penetrate the polymer micelles to provide targeted protection against polymer aging and improve antioxidant coverage is crucial. Furthermore, conventional water-based emulsion antioxidants suffer from poor stability, prone to delamination, precipitation, and oily bleeds, hindering their use and long-term storage. Therefore, developing highly stable emulsion antioxidants is crucial for polymer applications in emulsion polymerization. Summary of the Invention

[0005] The main purpose of the present invention is to provide an aqueous emulsion antioxidant with small particle size, high stability, long storage time and good anti-aging performance, as well as a preparation method and application thereof.

[0006] In a first aspect of the present invention, there is provided an aqueous emulsion antioxidant comprising an oil-soluble antioxidant, an emulsifier, a defoaming agent and water;

[0007] The oil-soluble antioxidant comprises at least one compound represented by formula I;

[0008] in:

[0009] R1 is a C1-C4 alkyl group;

[0010] R2 and R3 are each independently selected from one of C1-C4 alkyl, -CH2-S-R4 or -CH2-CH2-COO-R4;

[0011] R4 is C8-C 18 or C8-C 12 Alkyl;

[0012] The emulsifier includes one or more of anionic surfactants, nonionic surfactants and protective colloids.

[0013] When the anionic surfactants described in the present invention are used in combination with nonionic surfactants, the two types of surfactant molecules alternately adsorb on the surface of latex particles, with nonionic surfactant molecules "wedged" between the ionic surfactant molecules. This increases the distance between the surfactants on the latex particle surface, while the electrostatic shielding effect of the nonionic surfactant significantly reduces the electrostatic tension on the latex particle surface, increasing the adsorption fastness of the emulsifier on the latex particles and thus improving the stability of the polymer emulsion. Furthermore, since ionic surfactants stabilize emulsions primarily through electrostatic repulsion, while nonionic surfactants primarily rely on hydration, the combined use of the two emulsifiers forms a thick hydration layer on the latex particle surface, even when there is strong electrostatic repulsion between the latex particles. This dual effect results in a highly stable emulsion.

[0014] The protective colloid molecules described in this invention are adsorbed on the surface of latex particles, forming a thick hydration layer that prevents the particles from colliding and coalescing. Furthermore, because the protective colloid is soluble in the aqueous phase, it increases the viscosity of the system, which in turn increases the resistance to collision between latex particles, further stabilizing the emulsion.

[0015] The above-mentioned aqueous emulsion antioxidant, as a preferred embodiment, is made from the following raw materials in parts by weight: 10-70 parts of oil-soluble antioxidant, 3-30 parts of emulsifier, 0.001-1 part of defoaming agent, and 30-70 parts of water.

[0016] The above-mentioned aqueous emulsion antioxidant, as a preferred embodiment, the compound represented by formula I includes at least one compound represented by formula Ia-Ig;

[0017] The structural formula of the compound shown in Formula Ia is:

[0018] The structural formula of the compound shown in Formula Ib is:

[0019] The structural formula of the compound shown in Formula Ic is:

[0020] The structural formula of the compound represented by Formula Id is:

[0021] The structural formula of the compound represented by Formula 1e is:

[0022] The structural formula of the compound shown in Formula If is:

[0023] The structural formula of the compound shown in Formula Ig is:

[0024] Where: R is C7-C 18 At least one of the alkyl groups, preferably, R is C7-C9, C 12 -C 18 At least one of the alkyl groups.

[0025] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the oil-soluble antioxidant is 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid C7-C9 mixed ester.

[0026] According to some embodiments of the aqueous emulsion antioxidant described herein, the oil-soluble antioxidant is 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionic acid C13-15 branched and linear alkyl ester.

[0027] According to some embodiments of the aqueous emulsion antioxidant described herein, the oil-soluble antioxidant is 4,6-bis(octylthiomethyl)-o-cresol.

[0028] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the oil-soluble antioxidant is 2,4-di-tert-butyl-6-n-octylthiomethylenephenol.

[0029] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the emulsifier includes or consists of an anionic surfactant, a nonionic surfactant and a protective colloid; or the emulsifier includes or consists of an anionic surfactant and a nonionic surfactant.

[0030] According to some embodiments of the aqueous emulsion antioxidant described herein, the emulsifier includes or consists of anionic carboxylates, anionic sulfates, nonionic ethers, and protective colloids.

[0031] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the emulsifier includes or consists of anionic sulfates and nonionic higher fatty alcohols.

[0032] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the anionic surfactant includes at least one of a carboxylate surfactant, a sulfate surfactant, a sulfonate surfactant, and a phosphate surfactant.

[0033] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the carboxylate surfactant is fatty alcohol polyoxyethylene ether carboxylate, oleate soap, ricinoleate soap, rosin acid soap, fatty acid soap or tall oil soap.

[0034] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the sulfate surfactant is polyoxyethylene alkylphenol ether sulfate, fatty alcohol polyoxyethylene ether sulfate or arylalkylphenol polyoxyethylene ether sulfate.

[0035] According to some embodiments of the aqueous emulsion antioxidant described herein, the sulfonate surfactant is an alkyl sulfonate, alkylbenzene sulfonate, alkylnaphthalene sulfonate, alkyl succinate sulfonate, disodium succinate sulfonate mixture, fatty amide taurate, such as sodium lauryl sulfonate, polyoxyethylene alkoxy ether sulfonate, or fatty amide sarcosinate.

[0036] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the phosphate surfactant is fatty acid polyoxyethylene ether phosphate, polyoxyethylene alkylphenol ether phosphate or alkyl polyoxyethylene ether phosphite monoester and diester.

[0037] The nonionic surfactant is at least one of esters, ethers or higher fatty alcohols.

[0038] According to some embodiments of the aqueous emulsion antioxidant described herein, the ester is polyoxyethylene carboxylate, polyol carboxylate or polyoxyethylene polyol carboxylate.

[0039] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the ethers are polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl ethers, fatty alcohol polyoxyethylene ethers, and condensates of fatty alcohols and ethylene oxide.

[0040] According to some embodiments of the aqueous emulsion antioxidant described in this application, the higher fatty alcohol is hexadecanol, octadecanol, C 16-17Branched chain fatty alcohol or polyoxyethylene stearyl alcohol.

[0041] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the protective colloid is at least one of polyvinyl alcohol, sodium polymethacrylate, polyethylene glycol, polyvinyl pyrrolidone, hydroxyethyl cellulose, hydroxymethyl cellulose, xanthan gum, gelatin, and gum arabic.

[0042] According to some embodiments of the aqueous emulsion antioxidant described herein, the emulsifier includes potassium ricinoleate soap, sodium fatty alcohol polyoxyethylene ether sulfate, fatty alcohol polyoxyethylene ether, and xanthan gum. The emulsifier is particularly suitable for the oily antioxidant of Formula Ia, Ib, Ic, Id, and If.

[0043] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the emulsifier includes hexadecanol / octadecanol / C 16-17 Branched fatty alcohol / polyoxyethylene octadecyl alcohol, sodium lauryl sulfonate. The emulsifier is particularly suitable for the oily antioxidant of formula Ia, Ib, Ic, Id, If.

[0044] According to some embodiments of the aqueous emulsion antioxidant described in the present application, the defoaming agent is at least one of silicone oil, a higher alcohol fatty acid ester complex, polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, polyoxypropylene glycerol ether, and polyoxypropylene.

[0045] The second aspect of the present invention provides a method for preparing an aqueous emulsion antioxidant, wherein the preparation method is a phase transfer method or an ultrasonic dispersion method;

[0046] Preferably, the phase transfer method comprises the following steps:

[0047] (1) adding an emulsifier to an oil-soluble antioxidant in a heated and heat-insulating state to obtain a mixture system;

[0048] (2) adding water, preferably deionized water, to the mixed system obtained in step (1); after the addition is complete, performing heat preservation and cooling treatment; and then adding a defoaming agent to obtain the high-efficiency aqueous emulsion antioxidant;

[0049] More preferably, the ultrasonic dispersion method comprises the following steps:

[0050] a. Heat the oil-soluble antioxidant, add the emulsifier, and stir to mix evenly;

[0051] b. Add water, preferably deionized water, to the mixed system obtained in step a and stir to obtain an aqueous antioxidant system;

[0052] c. The aqueous antioxidant system obtained in step b is ultrasonically dispersed, stirred and cooled, and then a defoaming agent is added and discharged to obtain the efficient aqueous emulsion antioxidant.

[0053] According to some embodiments of the preparation method described in the present application, in step (1), an emulsifier is added to the oil-soluble antioxidant heated at a holding temperature of 50-180° C., and stirred at a stirring speed of 30-600 rpm for 10-60 minutes; preferably, the emulsifier includes an anionic surfactant, a nonionic surfactant, and a protective colloid;

[0054] According to some embodiments of the preparation method described in the present application, in step (2), deionized water is added dropwise to the mixed system obtained in step (1) at a stirring temperature of 50-100° C. and a stirring speed of 300-3000 rpm. After the system becomes thinner and becomes yogurt-like, the stirring speed is reduced to 30-600 rpm.

[0055] After the deionized water is added, keep warm for 30-60 minutes, cool to a temperature below 50°C, and then add the defoaming agent and discharge.

[0056] According to some embodiments of the preparation method described herein, in step a, the oil-soluble antioxidant is heated to 30-70°C.

[0057] According to some embodiments of the preparation method described herein, the emulsifier includes an anionic surfactant and a nonionic surfactant.

[0058] According to some embodiments of the preparation method described in the present application, in step c, the temperature of ultrasonic dispersion is controlled below 80°C, and the ultrasonic dispersion time is 30 min; the ultrasonically dispersed system is cooled to below 50°C under a stirring speed of 300 rpm, and a defoaming agent is added and the material is discharged.

[0059] When the phase transfer method is used to prepare aqueous emulsion antioxidants, the best emulsifier is a combination of anionic carboxylates + anionic sulfates + nonionic ethers + protective colloids.

[0060] When using an aqueous emulsion antioxidant prepared by ultrasonic dispersion method, the best emulsifier is a combination of anionic sulfates + non-ionic higher fatty alcohols.

[0061] The third aspect of the present invention provides a polymer material containing the aqueous emulsion antioxidant described in the first aspect of the present invention or the aqueous emulsion antioxidant prepared by the preparation method described in the second aspect of the present invention.

[0062] According to some embodiments of the polymer material described in the present application, the polymer material is rubber and latex, which can be specifically selected from one or more of natural latex, nitrile latex, styrene butadiene latex, styrene butadiene rubber latex, chloroprene latex, isoprene latex, natural latex, latex polystyrene butadiene rubber, nitrile rubber, chloroprene rubber, ABS, ASA, MBS, polymethacrylate and copolymers thereof, polyvinyl chloride, polyvinyl acetate and copolymers thereof, and polytetrafluoroethylene.

[0063] The beneficial effects of the present invention are as follows: the high-efficiency aqueous emulsion antioxidant of the present invention utilizes the synergistic effect of the emulsifier to make it have good compatibility with the emulsion polymerized polymer and good anti-aging performance, and the emulsion antioxidant has high effective utilization rate, high stability, and can be stored for a long time.

[0064] The high-efficiency aqueous emulsion antioxidant of the present invention is an environmentally friendly aqueous product, which avoids the dust pollution and explosion risks caused by directly adding solid antioxidants, avoids the poor compatibility of polymer systems in traditional liquid antioxidant emulsion polymerization, and improves resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] FIG1 is a particle size diagram of the aqueous emulsion antioxidant obtained in Example 2 of the present application. DETAILED DESCRIPTION

[0066] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the following embodiments and accompanying drawings. The specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention in any way. In addition, descriptions of known structures and techniques are omitted in the following description to avoid unnecessary confusion regarding the concepts of the present disclosure. Such structures and techniques are also described in many publications.

[0067] Some of the raw materials used in the examples of the present invention come from the following sources:

[0068] 3,5-Di-tert-butyl-4-hydroxyphenylpropionic acid C7-C9 mixed esters (RIANOX 1135): Tianjin Li'anlong New Materials Co., Ltd., CAS No.: 125643-61-0;

[0069] Potassium ricinoleate soap: Tianjin Li'anlong New Materials Co., Ltd., CAS No.: 8013-05-6;

[0070] Sodium fatty alcohol polyoxyethylene ether sulfate: Zanyu Technology Group Co., Ltd., CAS No.: 9004-82-4;

[0071] Fatty alcohol polyoxyethylene ether: Suzhou Yuantairun Chemical Co., Ltd., CAS No.: 52292-17-8;

[0072] Xanthan gum: Hubei Qifei Pharmaceutical Chemical Co., Ltd., CAS No.: 11138-66-2;

[0073] Polyoxyethylene polyoxypropanolamine ether: Hubei Chengfeng Chemical Co., Ltd.

[0074] 3,5-Bis(1,1-dimethylethyl)-4-hydroxyphenylpropionic acid C13-15 branched and linear alkyl esters (RIANOX 1315): Tianjin Li'anlong New Materials Co., Ltd., CAS No.: 171090-93-0;

[0075] Octadecanol: Shanghai Better Chemical Co., Ltd., CAS No.: 112-92-5;

[0076] Sodium lauryl sulfate: Jinan Daorong Chemical Co., Ltd., CAS No.: 151-21-3;

[0077] Polyoxypropylene glycerol ether: Jining Tangyi Chemical Co., Ltd., CAS No.: 25791-96-2;

[0078] 4,6-Bis(octylthiomethyl)-o-cresol (RIANOX 1520): Tianjin Li'anlong New Materials Co., Ltd., CAS No.: 110553-27-0.

[0079] Example 1

[0080] A water-based emulsion antioxidant comprises the following raw materials in parts by weight: an oil-soluble antioxidant, an emulsifier, a defoaming agent, and deionized water;

[0081] Oil-soluble antioxidant: (3,5-di-tert-butyl-4-hydroxyphenylpropionic acid C7-C9 mixed ester (RIANOX 1135)) 50 parts by weight;

[0082] Emulsifier: 3 parts by weight of potassium ricinoleate soap, 3 parts by weight of sodium sulfate of fatty alcohol polyoxyethylene ether, 2 parts by weight of fatty alcohol polyoxyethylene ether and 1 part by weight of xanthan gum;

[0083] Defoaming agent: 1 part by weight of polyoxyethylene polyoxypropanolamine ether;

[0084] The preparation is carried out by phase transfer method, comprising the following steps:

[0085] (1) Add 50 parts of oil-soluble antioxidant 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid C7-C9 mixed ester (RIANOX 1135) to the reactor, heat it to maintain the temperature at 70°C, and stir it at a low speed of 30-600 rpm to mix evenly;

[0086] (2) Add 3 parts of potassium ricinoleate soap, 3 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 2 parts of fatty alcohol polyoxyethylene ether, and 1 part of xanthan gum to the reactor and stir at 600 rpm to mix them with the antioxidant melt for 10-60 min;

[0087] (3) At 70°C, high-speed stirring was started at a stirring rate of 3000 rpm, and 40 parts of deionized water were added dropwise to the reactor. After the aqueous system became thin, the stirring rate was reduced to 600 rpm;

[0088] (4) After adding water, the aqueous emulsion is kept warm for 30 minutes, and then cooled to below 50°C, and 1 part of defoaming agent polyoxyethylene polyoxypropanolamine ether is added to obtain a highly stable and efficient aqueous emulsion antioxidant.

[0089] Example 2

[0090] A water-based emulsion antioxidant comprises the following raw materials in parts by weight: an oil-soluble antioxidant, an emulsifier, a defoaming agent, and deionized water;

[0091] Oil-soluble antioxidant: 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionic acid C 13-15 50 parts by weight of branched and linear alkyl esters (RIANOX 1315);

[0092] Emulsifier: 1 part by weight of stearyl alcohol, 2 parts by weight of sodium lauryl sulfate;

[0093] Defoaming agent: 0.001 parts by weight of polyoxypropylene glycerol ether;

[0094] The preparation method is ultrasonic dispersion method, which includes the following steps:

[0095] a. Add 50 parts of an oil-soluble antioxidant 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionic acid C13-15 branched and linear alkyl ester (RIANOX 1315) to the reactor and heat to 50°C;

[0096] b. Add 1 part of octadecyl alcohol and 2 parts of sodium lauryl sulfate, stir well, then add 47 parts of deionized water and continue stirring for 30 minutes;

[0097] c. Then place the aqueous antioxidant system in an ultrasonic disperser and maintain ultrasonication below 80°C for 30 minutes;

[0098] d. The ultrasonically dispersed aqueous antioxidant was cooled to below 50°C under stirring at a speed of 300 rpm, and a defoaming agent was added to obtain a highly stable aqueous emulsion antioxidant.

[0099] The particle size diagram of the aqueous emulsion antioxidant obtained in Example 2 is shown in FIG1 ;

[0100] As can be seen from FIG1 , the overall particle size of the obtained aqueous emulsion antioxidant is micro-nanoscale, the particle size is small, and the particle size distribution range is very narrow.

[0101] Example 3

[0102] A water-based emulsion antioxidant is provided, which differs from Example 1 in that the oil-soluble antioxidant used is 4,6-bis(octylthiomethyl)-o-cresol (RIANOX 1520).

[0103] Example 4

[0104] A water-based emulsion antioxidant is provided, which differs from Example 2 in that the oil-soluble antioxidant used is 2,4-di-tert-butyl-6-n-octylthiomethylenephenol.

[0105] Example 5

[0106] A water-based emulsion antioxidant, which is different from Example 2 in that the oil-soluble antioxidant used is 4,6-bis(octylthiomethyl)-o-cresol (RIANOX 1520).

[0107] Comparative Example 1

[0108] A water-based emulsion antioxidant is different from the water-based emulsion antioxidant described in Example 1 in that the emulsifiers used are 2 parts by weight of gum arabic (non-ionic emulsifier), 5 parts by weight of stearic acid (anionic surfactant), and 1 part of xanthan gum.

[0109] Comparative Example 2

[0110] An aqueous emulsion antioxidant is different from the aqueous emulsion antioxidant described in Example 2 in that the emulsifier used is 2 parts by weight of N-dodecyldimethylamine (cationic surfactant) and 1 part by weight of cetyl alcohol.

[0111] Comparative Example 3

[0112] A water-based emulsifier is different from the water-based emulsion antioxidant described in Example 1 in that the oil-soluble antioxidant used is bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.

[0113] Comparative Example 4

[0114] A water-based emulsifier is different from the water-based emulsion antioxidant described in Example 2 in that the oil-soluble antioxidant used is pentaerythritol distearyl diphosphite.

[0115] Performance study of the aqueous emulsion antioxidant described in this application:

[0116] The test method is as follows:

[0117] 1. Volume average particle size: Bettersize2600 laser particle size distribution analyzer is used to test the particle size of water-based emulsion antioxidants;

[0118] 2. Centrifugal stability: Centrifuge at 5000 rpm for 30 minutes to observe whether there is clear liquid or precipitation;

[0119] 3. Storage stability: Leave the emulsion at room temperature and observe whether there is any clear liquid or sedimentation;

[0120] 4. Anti-aging performance: Add a certain amount of emulsion antioxidant to styrene-butadiene latex and mix evenly. Make the mixed latex into a film, age it at 150℃ for 3h, and test the color of the film.

[0121] The test results are shown in Table 1:

[0122] Table 1

[0123] As can be seen from Table 1, the high-efficiency aqueous emulsion antioxidant described in the present application has a small particle size, high stability, and excellent aging performance. The aqueous emulsions described in Comparative Examples 1 and 2 do not use the types and combinations of emulsifiers in the present application, so the emulsion particle size is significantly large, the emulsion centrifugal stability and storage stability are very low, and the anti-aging performance is also very poor due to the influence of the emulsion particle size and stability. Comparative Examples 3 and 4 use other oil-soluble antioxidants, so their emulsion particle size is larger, the emulsion stability is lower, and their anti-aging performance is significantly poor.

[0124] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. An aqueous emulsion antioxidant, comprising an oil-soluble antioxidant, an emulsifier, a defoaming agent and water; The oil-soluble antioxidant comprises at least one compound of formula I, in: R1 is a C1-C4 alkyl group; R2 and R3 are each independently selected from one of C1-C4 alkyl, -CH2-S-R4 or -CH2-CH2-COO-R4; R4 is C8-C 18 or C8-C 12 The alkyl group; The emulsifier includes one or more of anionic surfactants, nonionic surfactants and protective colloids.

2. The aqueous emulsion antioxidant according to claim 1, characterized in that The invention is prepared from the following raw materials in parts by weight: 10-70 parts of oil-soluble antioxidant, 3-30 parts of emulsifier, 0.001-1 part of defoamer and 30-70 parts of water.

3. The aqueous emulsion antioxidant according to claim 1, characterized in that The compound represented by formula I includes at least one of the compounds represented by formulas Ia-Ig; The structural formula of the compound shown in Formula Ia is: The structural formula of the compound shown in Formula Ib is: The structural formula of the compound shown in Formula Ic is: The structural formula of the compound shown in Formula Id is: The structural formula of the compound shown in Formula Ie is: The structural formula of the compound shown in Formula If is: The structural formula of the compound shown in formula Ig is: Where: R is C7-C 18 At least one of the alkyl groups, preferably, R is C7-C9, C 12 -C 18 At least one of the alkyl groups; Preferably, the oil-soluble antioxidant is 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid C7-C9 mixed ester; Preferably, the oil-soluble antioxidant is 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionic acid C13-15 branched and linear alkyl ester; Preferably, the oil-soluble antioxidant is 4,6-bis(octylthiomethyl)-o-cresol; Preferably, the oil-soluble antioxidant is 2,4-di-tert-butyl-6-n-octylthiomethylenephenol.

4. The aqueous emulsion antioxidant according to claim 1, characterized in that The emulsifier includes or consists of anionic surfactant, nonionic surfactant and protective colloid; or the emulsifier includes or consists of anionic surfactant and nonionic surfactant; Preferably, the emulsifier includes or consists of anionic carboxylates, anionic sulfates, nonionic ethers and protective colloids; Preferably, the emulsifier includes or consists of anionic sulfates and nonionic higher fatty alcohols.

5. The aqueous emulsion antioxidant according to claim 4, characterized in that The anionic surfactant includes at least one of a carboxylate surfactant, a sulfate surfactant, a sulfonate surfactant, and a phosphate surfactant; Preferably, the carboxylate surfactant is fatty alcohol polyoxyethylene ether carboxylate, oleate soap, ricinoleate soap, rosin acid soap, fatty acid soap or tall oil soap; More preferably, the sulfate surfactant is polyoxyethylene alkylphenol ether sulfate, fatty alcohol polyoxyethylene ether sulfate or arylalkylphenol polyoxyethylene ether sulfate; Further preferably, the sulfonate surfactant is alkyl sulfonate, alkylbenzene sulfonate, alkylnaphthalene sulfonate, alkyl succinate sulfonate, disodium succinate sulfonate mixture, fatty amide taurate, polyoxyethylene alkoxy ether sulfonate or fatty amide sarcosinate; More preferably, the phosphate surfactant is fatty acid polyoxyethylene ether phosphate, polyoxyethylene alkylphenol ether phosphate or alkyl polyoxyethylene ether phosphite monoester and diester; The nonionic surfactant is at least one of esters, ethers or higher fatty alcohols; Preferably, the ester is polyoxyethylene carboxylate, polyol carboxylate or polyoxyethylene polyol carboxylate; More preferably, the ether is a polyoxyethylene alkyl aryl ether, a polyoxyethylene alkyl ether or a fatty alcohol polyoxyethylene ether, a condensate of a fatty alcohol and ethylene oxide; More preferably, the higher fatty alcohol is hexadecanol, stearyl alcohol, C 16-17 Branched chain fatty alcohol or polyoxyethylene stearyl alcohol.

6. The aqueous emulsion antioxidant according to claim 4, characterized in that The protective colloid is at least one of polyvinyl alcohol, sodium polymethacrylate, polyethylene glycol, polyvinyl pyrrolidone, hydroxyethyl cellulose, hydroxymethyl cellulose, xanthan gum, gelatin, and gum arabic; The defoaming agent is at least one of silicone oil, high carbon alcohol fatty acid ester complex, polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, polyoxypropylene glycerol ether and polyoxypropylene.

7. A method for preparing an aqueous emulsion antioxidant, characterized in that: The preparation method is a phase transfer method or an ultrasonic dispersion method; Preferably, the phase transfer method comprises the following steps: (1) adding an emulsifier to an oil-soluble antioxidant in a heated and heat-insulating state to obtain a mixture system; (2) adding water to the mixed system obtained in step (1), and after the addition is completed, performing heat preservation and cooling treatment, and then adding a defoaming agent and a protective colloid to obtain the aqueous emulsion antioxidant; More preferably, the ultrasonic dispersion method comprises the following steps: a. Heat the oil-soluble antioxidant, add the emulsifier and mix well; b. adding water to the mixed system obtained in step a to obtain an aqueous antioxidant system; c. The aqueous antioxidant system obtained in step b is ultrasonically dispersed, cooled, and then a defoaming agent is added to obtain the highly efficient aqueous emulsion antioxidant.

8. The preparation method according to claim 7, characterized in that: In step (1), an emulsifier is added to the oil-soluble antioxidant at a heating and insulation temperature of 50-180° C., and stirred at a stirring speed of 30-600 rpm for 10-60 min; preferably, the emulsifier comprises an anionic surfactant, a nonionic surfactant and a protective colloid; Preferably, in step (2), deionized water is added dropwise to the mixed system obtained in step (1) at a stirring temperature of 50-100° C. and a stirring speed of 300-3000 rpm, and the stirring speed is reduced to 30-600 rpm; After the deionized water is added, keep warm, cool down to a temperature below 50°C, add defoamer and protective colloid and discharge.

9. The preparation method according to claim 7, characterized in that: In step a, the oil-soluble antioxidant is heated to 30-70° C.; Preferably, the emulsifier comprises anionic surfactant and nonionic surfactant; Preferably, in step c, the system dispersed by ultrasound is stirred at a temperature of 50-70° C. for 30 minutes, then cooled to below 50° C., and a defoaming agent is added and discharged.

10. A polymer material, characterized in that: Containing the aqueous emulsion antioxidant according to any one of claims 1 to 6 or the aqueous emulsion antioxidant prepared by the preparation method according to any one of claims 7 to 9; Preferably, the polymer material is rubber and latex, more preferably, the polymer material is selected from one or more of natural latex, nitrile latex, styrene butadiene latex, styrene butadiene latex, chloroprene latex, isoprene latex, natural latex, latex polystyrene butadiene rubber, nitrile rubber, chloroprene rubber, ABS, ASA, MBS, polymethacrylate and copolymers thereof, polyvinyl chloride, polyvinyl acetate and copolymers thereof, and polytetrafluoroethylene.

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