Emulsion type antioxidant as well as preparation method and application thereof

Abstract

The invention discloses an emulsion type antioxidant as well as a preparation method and application thereof, and belongs to the fields of chemical engineering and material science. The emulsion-type antioxidant comprises: a) a hindered phenol antioxidant dispersed in water in the form of particles; b) an emulsifier dissolved and dispersed in water; c) a surfactant dissolved and dispersed in water; d) controlling the content of water and dissolved oxygen within 0.3 mg / L; and e) inevitable oxidation products, and the mass ratio of the content of the oxidation degradation products to the hindered phenol antioxidant is controlled within 5% by adopting a spectrum method. The preparation method comprises the following steps: firstly, treating water to control the content of dissolved oxygen in the water within 0.3 mg / L, and then dispersing, shearing and emulsifying the materials; the obtained emulsion type antioxidant is used for preparing PVC and PVC-containing products, and the influence on the performance of the PVC and the PVC-containing products is reduced.

Description

Technical Field

[0001] The invention relates to the fields of chemical engineering and material science, and in particular to an emulsion-type antioxidant and a preparation method and application thereof. Background Art

[0002] In the field of chemical engineering and materials science, antioxidants are very important chemicals that can improve the performance of polyvinyl chloride (PVC). The working principle of antioxidants is to prevent or slow down oxidation reactions by capturing free radicals, thereby protecting PVC from oxidative degradation. However, the oxidation products of antioxidants (such as hindered phenol antioxidants oxidized to quinones) have a destructive effect on the performance of PVC. When preparing emulsion-type antioxidants in the prior art, the materials need to be dispersed in hot water, but the water contains dissolved oxygen, which is more destructive to antioxidants than oxygen in the air, and will produce more oxidation products, which will catalyze the product (PVC) to be further oxidized, thereby affecting the performance of the product (PVC).

[0003] For example, the patent application document with Chinese patent application number 202311830025.X and application publication date April 2, 2024 discloses a method for quickly and efficiently preparing an emulsion-type composite antioxidant and the resulting products and applications. The method of the patent includes: step 1, dissolving the dispersant in deionized water, adding an emulsifier, a diffusant, and a thermal stabilizer to stir and dissolve, and the aqueous phase is prepared; step 2, taking out a portion of the aqueous phase for heating and stirring, heating to T+3°C, and then slowly adding an antioxidant to the aqueous phase in the reactor, wherein T is the hydrophilic-lipophilic equilibrium temperature of the O / W emulsion; step 3, when the reaction temperature is stable at the set value, the heat preservation reaction is carried out, and after completion, the set temperature is T-10°C, and then the remaining aqueous phase is added, and the heat preservation reaction is carried out after the temperature stabilizes; step 4, shear emulsification treatment is carried out to obtain an emulsion-type composite antioxidant. However, the emulsion-type composite antioxidant is prone to produce oxidation products and affects product performance.

[0004] Therefore, in order to reduce the content of oxidation products in the product, it is urgent to develop an emulsion-type antioxidant and its preparation method and application. Summary of the invention

[0005] 1. Problem to be solved

[0006] One of the purposes of the present invention is to provide an emulsion antioxidant, aiming to further improve the performance of the emulsion antioxidant, by controlling the content of oxidation products to be extremely low, thereby reducing the impact on the performance of the product PVC.

[0007] Another object of the present invention is to provide a method for preparing an emulsion-type antioxidant, so as to achieve extremely low content of oxidation products in the emulsion-type antioxidant, and further provide an application of the emulsion-type antioxidant in the preparation of PVC and PVC-containing products.

[0008] 2. Technical solution

[0009] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0010] According to the purpose of the present invention, the first aspect of the present invention provides an emulsion antioxidant, comprising:

[0011] a) a hindered phenolic antioxidant dispersed in water in the form of microparticles;

[0012] b) Emulsifier, dissolved and dispersed in water;

[0013] c) surfactant, dissolved and dispersed in water;

[0014] d) Water, dissolved oxygen content is controlled within 0.3 mg / L;

[0015] e) Inevitable oxidation products, the content of oxidation degradation products measured by spectroscopy to the mass ratio of hindered phenol antioxidant is controlled within 5%. Among them, the oxidation degradation products include quinone degradation products.

[0016] When the above technical solution is adopted, the content of oxidative degradation products is controlled to be extremely low by controlling the dissolved oxygen content in water, thereby preventing the oxidative products from damaging the performance of PVC products when used in PVC products.

[0017] As a possible implementation solution, the dissolved oxygen content in water is controlled within 0.25 mg / L.

[0018] As a possible implementation scheme, the mass ratio of the content of the oxidative degradation product to the hindered phenol antioxidant is controlled within 2%.

[0019] As a possible implementation scheme, the D50 average particle size of the emulsion-type antioxidant is 0.8-1.3 μm, and the D90 average particle size is 1.1-2.5 μm.

[0020] As a possible implementation scheme, according to the performance of PVC products, other additives may be selectively added to the emulsion antioxidant, for example, f) a heat stabilizer, dissolved in water, and / or dispersed in water as microparticles.

[0021] As a possible implementation scheme, the heat stabilizer is one or more of sodium perchlorate, mono- / di-pentaerythritol, and hydrotalcite.

[0022] As a possible implementation scheme, the components and mass fractions are as follows:

[0023]

[0024] As a possible implementation scheme, the hindered phenol antioxidant includes one or more of 1076, 245, 1135, 1010, 264, 2246, 300, 1520, and 1035, that is, specifically: the hindered phenol antioxidant includes β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (1076), triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (245), 3,5-di-tert-butyl-4-hydroxyphenyl propionate (1135), One or more antioxidants selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (1010), 2,6-di-tert-butyl-p-cresol (264), 2,2′-methylenebis(4-methyl-6-tert-butylphenol) (2246), 4,4′-thiobis(6-tert-butyl-3-methylphenol) (300), 4,6-bis(octylthiomethyl)-o-cresol (1520), and 2,2′-mercaptoethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1035).

[0025] As a possible implementation scheme, the emulsifier is one or more of polyvinyl alcohol, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and polyoxyethylene sorbitan monooleate.

[0026] As a possible implementation scheme, the surfactant is one or more of sorbitan trioleate, polyoxyethylene lauryl ether, octylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether.

[0027] The second aspect of the present invention provides a method for preparing an emulsion-type antioxidant, comprising the following steps:

[0028] S1. Dissolved oxygen removal process: Treat the water to control the dissolved oxygen content within 0.3 mg / L;

[0029] S2, dispersion process: dissolving or dispersing the hindered phenol antioxidant, emulsifier, and surfactant in the water treated in step S1, and keeping the temperature at 60°C to 80°C for 1 to 2 hours;

[0030] S3, shearing and emulsification process: after the material in step S2 is cooled to room temperature, shearing and emulsifying for 10 to 15 minutes is performed to obtain an emulsion-type antioxidant.

[0031] In the case of adopting the above technical solution, in step S1, by removing the dissolved oxygen content in the water, that is, controlling the dissolved oxygen content in the water within 0.3 mg / L, the content of oxidation products dispersed in the water can be controlled to be low. The content of oxidation degradation products is controlled to be within 5% of the mass ratio of the hindered phenol antioxidant by spectroscopy. In step S2, the reaction temperature and time will affect the product performance. If the temperature is too high, there will be side reactions and by-products, and if the temperature is too low, it will affect the reaction rate. Sufficient reaction time is an important factor to ensure the complete reaction. If the reaction time is too long, it will lead to overreaction and the generation of new by-products.

[0032] As a possible implementation scheme, it is preferred that the water is treated in step (1) so that the dissolved oxygen content therein is controlled within 0.25 mg / L.

[0033] As a possible implementation scheme, in step (1), the method for removing dissolved oxygen includes at least one of boiling deoxygenation treatment, low-pressure deoxygenation treatment, and nitrogen replacement deoxygenation treatment, wherein the dissolved oxygen content in deionized water is generally 5 to 8 mg / L. The present invention takes the treatment of dissolved oxygen in deionized water as an example:

[0034] (1) The boiling deoxygenation treatment process includes: heating the deionized water to boiling and keeping it in a boiling state for at least 10 minutes. When the above technical solution is adopted, the water is first boiled, and the dissolved oxygen in the water is removed by high temperature, and then the materials are added to prepare the emulsion type antioxidant. This method is simple and easy to implement, low in cost, and can effectively reduce the damage of oxygen to the antioxidant and improve the performance of the antioxidant; in addition, the boiling state is kept for at least 10 minutes to ensure that the dissolved oxygen in the water is basically removed.

[0035] (2) Low-pressure deoxygenation treatment: Deionized water is placed in a low-pressure environment, and the pressure range is maintained at 3.3-6.7 kPa for 0.5-1 h. When the above technical solution is adopted, the water is deoxygenated by vacuum equipment, and then the materials are added to prepare the emulsion antioxidant. This method can more thoroughly remove the dissolved oxygen in the water and further improve the performance of the antioxidant, but it requires a certain amount of equipment investment and is relatively expensive. Among them, the pressure range of low-pressure deoxygenation is between 3.3 and 6.7 kPa absolute pressure. In this pressure range, the boiling point of water will be reduced to the corresponding temperature (for example, when the absolute pressure is about 3.3 kPa, the boiling point of water is about 25°C). In this way, deoxygenation can be achieved at a lower temperature, avoiding the problems of energy consumption and equipment corrosion caused by high-temperature deoxygenation.

[0036] Inert gas replacement deoxygenation treatment: Inert gases include nitrogen, argon, helium, etc. Deionized water is continuously fed with inert gas, the inert gas flow rate is controlled at 10-50 mL / min, and the time for passing the inert gas is 5-10 minutes. In the case of the above technical solution, the oxygen in the water is replaced by inert gas, and then the materials are added to prepare the emulsion type antioxidant. This method can effectively prevent new oxygen from entering the water body, thereby further affecting the performance of the antioxidant. Moreover, since the amount of inert gas required for a small volume container is small, the internal dissolved oxygen can be quickly replaced to achieve the purpose of protection.

[0037] By adopting the above technical solution, the problem of how to more effectively remove dissolved oxygen in water is solved to reduce the damage of oxygen to antioxidants, thereby improving the performance of antioxidants; reduce production costs and process complexity to achieve a more economical antioxidant preparation process; and avoid new oxygen entering the water body during the preparation process, thereby further affecting the performance of the antioxidant.

[0038] As a possible implementation scheme, step S2 is carried out under normal pressure without applying any additional pressure; at the same time, step S2 can be carried out with or without cooling after the treatment in step S1. It is preferred to carry out step S2 after the water treated in step S1 is cooled to room temperature. Feeding at room temperature is conducive to smaller particle size of the material and less amount of oxidative degradation products.

[0039] As a possible implementation scheme, according to the performance of the PVC product, other additives may be selectively added in step S2, for example, a heat stabilizer may be added, dissolved in water, and / or dispersed in water in the form of microparticles.

[0040] As a possible implementation scheme, the heat stabilizer is one or more of sodium perchlorate, mono- / di-pentaerythritol, and hydrotalcite.

[0041] As a possible implementation scheme, in step S2, the components and mass fractions are as follows:

[0042]

[0043] As a possible implementation scheme, the hindered phenol antioxidant includes but is not limited to one or more of 1076, 245, 1135, 1010, 264, 2246, 300, 1520, and 1035, that is, specifically: the hindered phenol antioxidant includes β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester (1076), triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (245), 3,5-di-tert-butyl-4-hydroxyphenyl propionate octyl ester (1135 ), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (1010), 2,6-di-tert-butyl-p-cresol (264), 2,2′-methylenebis(4-methyl-6-tert-butylphenol) (2246), 4,4′-thiobis(6-tert-butyl-3-methylphenol) (300), 4,6-bis(octylthiomethyl)-o-cresol (1520), and one or more antioxidants selected from 2,2′-mercaptoethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1035).

[0044] As a possible implementation scheme, the emulsifier includes but is not limited to polyvinyl alcohol, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and polyoxyethylene sorbitan monooleate.

[0045] As a possible implementation scheme, the surfactant includes but is not limited to one or more of sorbitan trioleate, polyoxyethylene lauryl ether, octylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether.

[0046] The third aspect of the present invention provides a use of the above-mentioned emulsion antioxidant in the preparation of PVC and PVC-containing products.

[0047] 3. Beneficial effects

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The emulsion-type antioxidant of the present invention controls the content of dissolved oxygen in water to control the content of oxidation products to be low, thereby preventing oxidation products from damaging the performance of PVC products when used in PVC products;

[0050] (2) In the preparation method of the emulsion-type antioxidant of the present invention, oxygen in the water is effectively removed by boiling water, removing dissolved oxygen at low pressure, and replacing with inert gas, thereby reducing the damage of oxygen to the antioxidant, thereby improving the performance of the antioxidant; compared with the prior art, this method can completely remove oxygen from the water and further improve the performance of the antioxidant; wherein: the use of inert gas to replace oxygen effectively prevents the entry of new oxygen, thereby avoiding the damage of oxygen to the antioxidant. Compared with the prior art, this method more effectively prevents the damage of oxygen to the antioxidant and further improves the performance of the antioxidant;

[0051] (3) The preparation method of the present invention is simple to operate, does not require special equipment and environment, and reduces production costs and process complexity; compared with the prior art, the preparation method of the present invention is simpler and easier to operate, suitable for large-scale production, and has good industrial application prospects;

[0052] (4) The preparation method of the present invention can not only remove oxygen from water, but also prevent the entry of new oxygen during the preparation process, thereby more comprehensively ensuring the performance of the antioxidant; compared with the prior art, this method more comprehensively considers the factors affecting the performance of the antioxidant, and further improves the performance of the antioxidant;

[0053] (5) The preparation method of the present invention can be used not only to prepare emulsion-type antioxidants, but also to prepare other chemicals, and has a wide range of applications. Compared with the prior art, this method is more universal and has higher practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 The UV-visible spectrophotometers of the unoxidized antioxidant of Example 1 and the oxidized antioxidant of Comparative Example 1 are shown. DETAILED DESCRIPTION

[0055] The present invention is further described below in conjunction with specific embodiments.

[0056] The present invention provides a method for preparing an emulsion-type antioxidant, comprising the following steps:

[0057] S1. Dissolved oxygen removal process: deionized water is treated to control the dissolved oxygen content within 0.3 mg / L, preferably within 0.25 mg / L; the dissolved oxygen content in the deionized water is controlled by combining one or more of the following methods:

[0058] (1) The boiling deoxygenation process includes: heating the deionized water to boiling and keeping the boiling state for at least 10 minutes.

[0059] (2) Low-pressure deoxygenation treatment: Place deionized water in a low-pressure environment and maintain the pressure in the range of 3.3 to 6.7 kPa for 0.5 to 1 hour.

[0060] (3) Inert gas replacement and deoxygenation treatment: Inert gases include nitrogen, argon, helium, etc. Deionized water is continuously passed through the inert gas, the inert gas flow rate is controlled at 10 to 50 mL / min, and the time for passing the inert gas is 5 to 10 minutes.

[0061] S2, dispersion process: dissolving or dispersing the hindered phenol antioxidant, emulsifier, and surfactant in the water treated in step S1, and keeping the temperature at 60°C to 80°C for 1 to 2 hours; wherein the components and mass fractions are as follows:

[0062]

[0063] The hindered phenol antioxidant includes one or more of 1076, 245, 1135, 1010, 264, 2246, 300, 1520, and 1035; the emulsifier is polyvinyl alcohol, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and polyoxyethylene sorbitan monooleate; the surfactant is one or more of sorbitan trioleate, polyoxyethylene lauryl ether, octylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; the heat stabilizer is one or more of sodium perchlorate, mono- / di-pentaerythritol, and hydrotalcite.

[0064] S3, shearing and emulsification process: after the material in step S2 is cooled to room temperature, shearing and emulsifying for 10 to 15 minutes is performed to obtain an emulsion-type antioxidant.

[0065] The emulsion antioxidant prepared by the above method is measured by spectroscopy, and the content of oxidative degradation products is controlled within 5% of the mass ratio of hindered phenol antioxidant, the D50 average particle size is 0.8-1.3 μm, and the D90 average particle size is 1.1-2.5 μm. When used in PVC products, the aging whiteness is 88.4-91.3% and the thermal stability time is 430-490s.

[0066] Several methods for preparing emulsion antioxidants with specific material formulas are listed below. It should be noted that the present invention is not limited to these embodiments.

[0067] Example 1

[0068] This embodiment provides a method for preparing an emulsion-type antioxidant, and the specific preparation method is as follows:

[0069] S1. Dissolved oxygen removal process: Use boiling deoxygenation treatment, first add 200 parts of deionized water into a round-bottom flask, then heat to boiling, keep boiling for 10 minutes, and use high temperature to make the dissolved oxygen in the water escape;

[0070] S2, Dispersion process: Without waiting for the deionized water to cool down, put 30 parts of the pre-prepared antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester, 5 parts of the emulsifier polyoxyethylene sorbitan monooleate, and 5 parts of the surfactant polyoxyethylene lauryl ether into a round-bottom flask. Then adjust the water in the round-bottom flask to 70°C, and continue mechanical stirring to keep the temperature for 1 hour.

[0071] S3, shearing emulsification process: the antioxidant material is cooled to room temperature, and shearing emulsification is performed for 15 minutes to obtain the antioxidant prepared by deoxygenated water.

[0072] Example 2

[0073] This embodiment provides a method for preparing an emulsion-type antioxidant, and the specific preparation method is as follows:

[0074] S1. Dissolved oxygen removal process: Use boiling deoxygenation treatment, first add 200 parts of deionized water into a round-bottom flask, then heat to boiling, keep boiling for 10 minutes, and use high temperature to make the dissolved oxygen in the water escape;

[0075] S2, Dispersion process: Turn off the heating, let it stand for 2 hours, wait until the water temperature drops to room temperature, and put the pre-prepared antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester (15 parts), triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] (15 parts), emulsifier sodium dodecylbenzene sulfonate 5 parts, surfactant sorbitan trioleate 5 parts into the round-bottom flask. Then heat the water in the round-bottom flask to 70°C again, and continue mechanical stirring to keep the temperature for 1 hour.

[0076] S3, shearing emulsification process: the antioxidant material is cooled to room temperature, and shearing emulsification is performed for 15 minutes to obtain the antioxidant prepared by deoxygenated water.

[0077] Example 3

[0078] This embodiment provides a method for preparing an emulsion-type antioxidant, and the specific preparation method is as follows:

[0079] S1. Dissolved oxygen removal process: low-pressure deoxygenation treatment is used. A round-bottom flask containing 200 parts of deionized water is placed in a vacuum device. The pressure is reduced by vacuuming. The pressure range is maintained at 3.3 to 6.7 kPa for 0.5 to 1 hour, so that the dissolved oxygen in the water escapes under low pressure.

[0080] S2, dispersion process: when the dissolved oxygen in the water is controlled within 0.3 mg / L, remove the round-bottom flask and place it in a heating jacket, add 30 parts of the pre-prepared antioxidant 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid octyl ester, 5 parts of the emulsifier polyoxyethylene sorbitan monooleate, and 5 parts of the surfactant octylphenol polyoxyethylene ether into the round-bottom flask. Heat the water in the round-bottom flask to 70°C, and continue mechanical stirring to keep the temperature for 1 hour.

[0081] S3, shearing emulsification process: the antioxidant material is cooled to room temperature, and shearing emulsification is performed for 15 minutes to obtain the antioxidant prepared by deoxygenated water.

[0082] Example 4

[0083] This embodiment provides a method for preparing an emulsion-type antioxidant, and the specific preparation method is as follows:

[0084] S1. Dissolved oxygen removal process: nitrogen replacement deoxygenation treatment is adopted. 200 parts of deionized water are injected into a round-bottom flask, and nitrogen is continuously introduced. The nitrogen flow rate is controlled at 10-50 mL / min. The nitrogen introduction time is 5-10 minutes, so that the nitrogen replaces the oxygen in the water.

[0085] S2, dispersion process: after the oxygen content in the water is detected to be within 0.3 mg / L, the round-bottom flask is removed and placed in a heating mantle, and 30 parts of the pre-prepared antioxidant triethylene glycol bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 5 parts of the emulsifier polyoxyethylene sorbitan monooleate, and 5 parts of the surfactant fatty alcohol polyoxyethylene ether are added into the round-bottom flask. The water in the round-bottom flask is heated to 70°C, and the reaction is kept warm for 1 hour with continuous mechanical stirring.

[0086] S3, shearing emulsification process: the antioxidant material is cooled to room temperature, and shearing emulsification is performed for 15 minutes to obtain the antioxidant prepared by deoxygenated water.

[0087] Example 5

[0088] This embodiment provides a method for preparing an emulsion-type antioxidant, and the specific preparation method is as follows:

[0089] S1. Dissolved oxygen removal process:

[0090] S11. Low-pressure deoxygenation treatment: Place a round-bottom flask containing 200g of deionized water in a vacuum device, reduce the pressure by vacuuming, maintain the pressure range at 3.3-6.7kPa for 0.5-1h, and allow the dissolved oxygen in the water to escape under low pressure.

[0091] S12, boiling deoxygenation treatment: then put the deionized water after the low-pressure deoxygenation treatment in step S11 into a heating jacket and heat the water to boiling, keep the boiling state for 30 minutes, and use the high temperature to make the dissolved oxygen in the water escape.

[0092] S2, dispersion process: without waiting for the deionized water to cool down, put 30 parts of the antioxidant β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl alcohol ester, 5 parts of the emulsifier polyoxyethylene sorbitan monooleate, and 5 parts of the surfactant polyoxyethylene lauryl ether into a round-bottom flask. Adjust the water in the round-bottom flask to 70°C, and continue mechanical stirring to keep the temperature for 1 hour.

[0093] S3, shearing emulsification process: the antioxidant material is cooled to room temperature, and shearing emulsification is performed for 15 minutes to obtain the antioxidant prepared by deoxygenated water.

[0094] Comparative Example 1

[0095] The preparation method of an emulsion-type antioxidant in this comparative example is basically the same as that in Example 1, except that: the process of removing dissolved oxygen in step S1 is not performed, and deionized water is directly used for the dispersion process in step S2 and the shear emulsification process in step S3.

[0096] Comparative Example 2

[0097] The preparation method of an emulsion-type antioxidant in this embodiment is basically the same as that in Embodiment 4, except that: air is introduced in step S1 instead of nitrogen.

[0098] Comparative Example 3

[0099] The preparation method of an emulsion-type antioxidant in this embodiment is basically the same as that in Embodiment 4, except that oxygen is introduced in step S1 instead of nitrogen.

[0100] Performance Testing

[0101] 1. Emulsion Antioxidant Test

[0102] The emulsion antioxidants obtained in the above examples and comparative examples were subjected to accelerated tests, and then their performance indicators were tested. The test method is as follows:

[0103] D50, D90 average particle size: BT-9300ST laser particle size analyzer produced by Dandong Better Instrument Co., Ltd.;

[0104] The steps for measuring oxidative degradation products by spectroscopy are as follows:

[0105] 1. Sample solution preparation: Accurately weigh 100 mg of emulsion antioxidant and place it in a 250 mL volumetric flask; accurately pipette 2 mL of tetrahydrofuran solution into the volumetric flask and gently shake it to dissolve the emulsion antioxidant; then use methanol to make the solution to the scale line of the volumetric flask and shake it thoroughly to obtain the sample solution to be tested.

[0106] 2. Preparation of antioxidant stock solution: Antioxidant 245 is used as a standard substance to calculate the total amount of phenolic groups in the antioxidant (the ultraviolet absorbance of each phenolic antioxidant is basically the same). Follow the same method as the above "sample solution preparation" to obtain the antioxidant stock solution.

[0107] 3. Preparation of standard solution series: Pipette appropriate volumes of stock solution into different volumetric flasks and make up to volume with methanol to prepare a series of standard solutions with concentrations of 5%, 10%, 20%, 50%, 80% and 100%.

[0108] 4. UV detection: Use methanol as the reference solution, place the sample solution and standard solutions of different concentrations into the sample light path, and detect the absorbance of the sample and standard solution at 276 nm.

[0109] 5. Draw a standard curve and calculate the content: Draw a standard curve. Substitute the average absorbance value of the sample solution at 276nm into the standard curve equation to calculate the concentration of the antioxidant in the sample. By calculating the content difference of samples with the same formula but different processes, the specific content of the degradation product can be known.

[0110] 6. The method has been verified for precision and accuracy, and it is determined that the difference between different samples is much greater than the repeatability and reproducibility RSD, which means that the influence of detection error is eliminated.

[0111] The results of the above tests are shown in Table 1 below:

[0112] Table 1 Test results of examples and comparative examples

[0113]

[0114]

[0115] From the test results in Table 1, it can be seen that the D50 average particle size of the emulsion antioxidant provided by the present invention is 0.8-1.3 μm, the D90 average particle size is 1.1-2.5 μm, the dissolved oxygen content is 0.06-0.23 mg / L, and the oxidative degradation product / phenol accounts for 0.31-1.21%. The optimal method is the method adopted in Example 5, which has the advantages of small particle size, narrow particle size distribution range, good stability, and high effective ingredient. The preparation method adopted by the present invention is simple to operate, low in energy consumption, and energy-saving and environmentally friendly.

[0116] Compared with Example 5, Comparative Examples 1, 2, and 3 respectively adopted untreated deionized water, air, and oxygen. Although the initial particle sizes of the antioxidants were similar, in the accelerated stability test, the antioxidants of Comparative Examples 1, 2, and 3 were more easily oxidized and destroyed, more easily agglomerated, and the particle sizes of D50 and D90 increased.

[0117] 2. Application test of emulsion antioxidant

[0118] The technical performance indicators of the emulsion antioxidants obtained in the above examples and comparative examples were tested, and the testing method is as follows:

[0119] Aging whiteness: The test method is determined in accordance with standard GB / T 15595-2008.

[0120] Thermal stability: The test method is determined in accordance with standard GB / T 2917.1-2002.

[0121] The results of the above tests are shown in Table 2 below:

[0122] Table 2 Test results of examples and comparative examples

[0123] Test items Aging whiteness (%) Thermal stability(s) Example 1 89.0 440 Example 2 89.3 450 Example 3 88.4 430 Example 4 91.2 490 Example 5 91.3 490 Comparative Example 1 80.3 380 Comparative Example 2 76.8 340 Comparative Example 3 74.4 300

[0124] It can be seen from the test results in Table 2 that the aging whiteness of the emulsion antioxidant provided by the present invention is 88-92, and the thermal stability test is 430-490s, and the application effect is good, among which the best method is Example 4; while in the comparative example, due to the gradual increase of dissolved oxygen in deionized water, the performance of the prepared antioxidant is poor, and the oxidation products of the antioxidant will further damage PVC, thereby causing the antioxidant emulsion to have a poor application effect in PVC.

[0125] The UV-visible spectrophotometers of the unoxidized antioxidant in Example 1 and the oxidized antioxidant in Comparative Example 1 are as follows: Figure 1 As shown: the larger absorption peak is the absorption peak of the emulsion antioxidant of Example 1, and the smaller absorption peak is the absorption peak of the emulsion antioxidant of Comparative Example 1. From the figure, it can be seen intuitively that the antioxidant in Comparative Example 1 is more degraded, indicating that the deoxygenation method can reduce degradation.

[0126] It should be noted that the applicant proved that it was the oxidative degradation products in the antioxidant that caused the poor application effect in PVC:

[0127] Sample ① prepared in Comparative Example 1;

[0128] Sample ② prepared in Example 1;

[0129] A small amount of hydrogen peroxide was added and sample ③ was prepared in the same manner as in Comparative Example 1.

[0130] After adding PVC to the three samples ①, ②, and ③, the PVC performance was evaluated: sample ①> blank> sample ②>> sample ③,

[0131] This shows that oxidative degradation products are not good for PVC.

[0132] Although the present invention has been described in detail above by means of general description, specific implementation methods and tests, it is obvious to those skilled in the art that some modifications or improvements may be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. An emulsion antioxidant, characterized in that: include: a) a hindered phenolic antioxidant dispersed in water in the form of microparticles; b) Emulsifier, dissolved and dispersed in water; c) surfactant, dissolved and dispersed in water; d) Water, dissolved oxygen content is controlled within 0.3 mg / L; e) Inevitable oxidation products: the content of the oxidation degradation products measured by spectroscopy is controlled within 5% of the mass ratio of the hindered phenol antioxidant.

2. An emulsion antioxidant according to claim 1, characterized in that: The dissolved oxygen content in water is controlled within 0.25 mg / L; the mass ratio of the content of oxidative degradation products to the hindered phenol antioxidant is controlled within 2%; the D50 average particle size of the emulsion antioxidant is 0.8-1.3 μm, and the D90 average particle size is 1.1-2.5 μm.

3. An emulsion-type antioxidant according to claim 2, characterized in that: The emulsion-type antioxidant further comprises, f) a heat stabilizer, dissolved in water, and / or dispersed in water in the form of microparticles.

4. An emulsion antioxidant according to claim 3, characterized in that: The components and mass fractions are as follows:

5. An emulsion antioxidant according to claims 1 to 4, characterized in that: The hindered phenol antioxidant includes one or more of 1076, 245, 1135, 1010, 264, 2246, 300, 1520, and 1035; the emulsifier is one or more of polyvinyl alcohol, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, and polyoxyethylene sorbitan monooleate; the surfactant is one or more of sorbitan trioleate, polyoxyethylene lauryl ether, octylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether; the heat stabilizer is one or more of sodium perchlorate, mono- / di-pentaerythritol, and hydrotalcite.

6. A method for preparing the emulsion antioxidant according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Dissolved oxygen removal process: Treat the water to control the dissolved oxygen content within 0.3 mg / L; S2, dispersion process: dissolving or dispersing the hindered phenol antioxidant, emulsifier, and surfactant in the water treated in step S1, and keeping the temperature at 60°C to 80°C for 1 to 2 hours; S3, shearing and emulsification process: after the material in step S2 is cooled to room temperature, shearing and emulsifying for 10 to 15 minutes is performed to obtain an emulsion-type antioxidant.

7. The method for preparing an emulsion-type antioxidant according to claim 6, characterized in that: In step (1), the water is treated so that the dissolved oxygen content is controlled within 0.25 mg / L.

8. The method for preparing an emulsion-type antioxidant according to claim 6, characterized in that: In step S1, the water is deionized water, and the dissolved oxygen content in the deionized water is reduced by one or more of the following methods: (1) Boiling deoxygenation treatment: Heat the deionized water to boiling and keep boiling for at least 10 minutes; (2) Low-pressure deoxygenation treatment: Deionized water is placed in a low-pressure environment, maintaining the pressure range of 3.3 to 6.7 kPa for 0.5 to 1 hour; (3) Inert gas replacement and deoxygenation treatment: Inert gases include nitrogen, argon, helium, etc. Deionized water is continuously passed through the inert gas, the inert gas flow rate is controlled at 10 to 50 mL / min, and the time for passing the inert gas is 5 to 10 minutes.

9. The method for preparing an emulsion antioxidant according to any one of claims 6 to 8, characterized in that: Step S2 is carried out under normal pressure.

10. Use of the emulsion antioxidant according to any one of claims 1 to 5 in the preparation of PVC and PVC-containing products.

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