A multifunctional rubber additive polynitrogen selenium azole and its preparation method and application

Abstract

The present invention relates to the field of multifunctional rubber additives, and specifically discloses a multifunctional rubber additive polyazole selenium and its preparation method and application. The method comprises: dissolving selenium dioxide and polyazole ligands in anhydrous ethanol respectively, then dropping the ethanol solution of selenium dioxide into the ethanol solution of polyazole under heating and stirring, and continuously reacting to obtain a solid precipitate; and filtering, washing, and drying the solid precipitate to obtain the multifunctional rubber additive polyazole selenium. The polyazole selenium rubber multifunctional additive prepared by the present invention can significantly improve the thermal oxidation aging resistance of the material, can stably exert the anti-aging effect for a long time, and has the advantage of reducing the amount of other additives used. At the same time, the preparation method of the present invention is environmentally friendly and pollution-free, low in cost, and high in yield.

Description

Technical Field

[0001] The invention relates to the field of multifunctional rubber additives, and in particular to a multifunctional rubber additive, polynitrogen selenium azole, and a preparation method and application thereof. Background Art

[0002] As a material with high elasticity at room temperature, rubber has special elasticity that other materials do not have. With the development of nearly a hundred years, the synthesis and processing technology of modern rubber has made great progress, and correspondingly, there are always many new problems that need to be solved. At present, the development direction of rubber materials is mainly high performance, functionalization, automation, green, energy saving and other aspects.

[0003] In addition to the base rubber, the rubber raw materials used to produce products also need to be combined with other additives to achieve the performance requirements of rubber products. Currently, the commonly used rubber additives are mainly divided into the following categories: vulcanizers, vulcanization accelerators, vulcanization activators, reinforcing agents and fillers, antioxidants, plasticizers, etc.

[0004] With the development in recent years, rubber materials are facing some difficulties, the most important of which are environmental protection, energy consumption, pollution and other issues. During the vulcanization process, vulcanization accelerators containing secondary amine groups (such as secondary sulfonyl amines, thiurams, dithiocarbamate accelerators, etc.) will react with nitrogen oxides in the air or in additives under certain conditions to generate stable carcinogenic nitrosamines, which will cause harm to the human body when used. As for antioxidants, the commonly used amine antioxidants for rubber mainly include p-phenylenediamine and diphenylamine. Although these antioxidants are anti-aging and anti-ozone, they are polluting and will pollute the environment.

[0005] In the face of environmental problems caused by rubber, some researchers have combined various additives that need to be added to rubber materials into one, and proposed the concept of "one dose with multiple functions" multifunctional additives, providing a new idea for the multifunctionality, high performance, green environmental protection and compounding of rubber additives. This rubber multifunctional additive not only has the functions of a single additive (such as vulcanization, promotion, anti-aging, etc.), but also can improve the performance of rubber, and has the characteristics of environmental protection and low consumption. Compared with the current commonly used method of adding multiple additives to perform their functions, the "one dose with multiple functions" multifunctional rubber additive only uses the same or less amount to achieve the effect of using multiple additives separately, thereby reducing the use of harmful additives, reducing environmental pollution, and reducing the complexity of mixing operations during processing and production. Therefore, the "one dose with multiple functions" multifunctional additive has excellent development prospects.

[0006] There are many ways to realize multifunctional rubber additives, not only by connecting existing commonly used accelerators with fillers or carriers, but also by combining accelerator groups with other substances. However, in general, the idea of ​​realizing multifunctional rubber additives is to combine related groups with vulcanization, acceleration and anti-aging effects to form a single substance, so that it has multiple functions at the same time.

[0007] Patent CN112062701A "A rubber accelerator diethyldithiocarbamate sulfone and its preparation method and application" disperses sodium diethyldithiocarbamate in an organic solvent under stirring, adds sulfonyl chloride to obtain a mixed solution, stirs, filters out the residue, washes, dries, crushes, and sieves to obtain the rubber accelerator diethyldithiocarbamate sulfone. Although the substance is a new accelerator, its synthesis method is relatively complicated, the organic solvent used has certain hazards, and the reaction temperature is low and difficult to control. Summary of the invention

[0008] In order to overcome the shortcomings and deficiencies of the above-mentioned technology, a new multifunctional rubber additive is synthesized. The purpose of the present invention is to provide a multifunctional rubber additive, polynitrogen selenium azole, and a preparation method and application thereof.

[0009] The present invention synthesizes a specific new type of selenium-centered complex, applies it to styrene-butadiene rubber with the help of experimental research and data analysis methods, thereby successfully synthesizing a selenium-centered rubber multifunctional additive, and the selenium-centered rubber multifunctional additive has an effect superior to that of the commonly used rubber additives added separately, thereby demonstrating the feasibility of the selenium-centered complex being used as a rubber multifunctional additive.

[0010] The purpose of the present invention is achieved through the following technical solutions:

[0011] A method for preparing a multifunctional rubber additive, polynitrogen selenium azole, comprises the following steps:

[0012] Selenium dioxide and polyazole ligand are dissolved in anhydrous ethanol respectively, and then the ethanol solution of selenium dioxide is added dropwise to the ethanol solution of polyazole ligand under heating and stirring conditions, and the reaction is continued to obtain a solid precipitate, which is then filtered, washed and dried to obtain the multifunctional rubber additive polyazole selenium.

[0013] Furthermore, the source of the selenium dioxide is commercially available selenium dioxide with a purity of 99 wt %, and the source of the polyazole ligand is commercially available polyazole ligand with a purity of 97-98 wt %.

[0014] Furthermore, the molar ratio of selenium dioxide to polyazole ligand is 1:(4.0-4.2).

[0015] Furthermore, the polyazole ligand includes but is not limited to: 3-mercapto-1,2,4-triazole, 5-mercapto-1-methyltetrazolyl, 5-mercapto-1-phenyltetrazolyl, and the like.

[0016] Furthermore, the temperature of the heating condition is 45-50° C., and the stirring rate of the stirring condition is 500-600 rpm.

[0017] Furthermore, the concentration of the selenium dioxide ethanol solution is 0.020-0.024 g / mL.

[0018] Furthermore, the concentration of the polyazole ligand in the ethanol solution is 0.076-0.128 g / mL.

[0019] Furthermore, the volume ratio of the selenium dioxide ethanol solution to the polyazole ligand ethanol solution is 1:(1-1.2).

[0020] Furthermore, the continuous reaction is carried out for 5-6 hours at a heating temperature of 45-50° C. and a stirring rate of 500-600 rpm.

[0021] The invention provides a multifunctional rubber additive, selenium polynitrogen azole, prepared by the above-mentioned preparation method.

[0022] The research idea of ​​the present invention is to synthesize a new multifunctional rubber additive with certain vulcanization promoting and heat-oxidative aging resistance effects. The tetravalent selenium ion is used as the center and coordinated with the polynitrogen azole selenium ligand to synthesize a new type of rubber multifunctional additive, and apply it to styrene-butadiene rubber to test its vulcanization and anti-aging properties, so as to determine the functionalization of the rubber additive.

[0023] The present invention adopts a one-step synthesis method, utilizes the dehydration condensation reaction of mercapto groups and oxides, combines positive tetravalent selenium ions with polyazole ligands under a heating and stirring environment, and successfully synthesizes polyazole selenium, a multifunctional rubber additive. The present invention selects selenium ions as the center because experiments have proven that selenium has the function of participating in vulcanization crosslinking and entering the crosslinking network, and at the same time, the oxide of selenium (i.e., selenium dioxide) is cheap and easy to obtain, and can be easily connected to polyazole ligands. The present invention selects polyazole selenium as a ligand because it contains a structure that promotes vulcanization (i.e., "-N=CS-") and an N atom that has an anti-aging effect, and there is a theoretical basis for having both a vulcanization promoting effect and an anti-thermal oxidative aging effect.

[0024] The multifunctional rubber additive polyazole selenium is a vulcanization accelerator for styrene-butadiene rubber and is also an antioxidant for styrene-butadiene rubber. Preferably, it comprises the following components in parts by weight: 100 parts of styrene-butadiene rubber, 50 parts of N550 carbon black, 5 parts of zinc oxide, 1 part of stearic acid, 1 part of sulfur, and 2 parts of multifunctional rubber additive polyazole selenium. Its performance is better than that of the commonly used vulcanization accelerator M (benzothiazole), and no waste gas is generated during its production process, and no dangerous chemical raw materials such as toxic gases, highly toxic substances or carcinogens are used.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] (1) The preparation method provided by the present invention uses anhydrous ethanol as a solvent, which can be recycled after the reaction is completed. The selected polyazole ligand is non-toxic, and the only by-product produced during the reaction is water, which is environmentally friendly and pollution-free.

[0027] (2) The present invention adopts an organic solvent and utilizes the dehydration condensation reaction of mercapto groups and oxides to synthesize the product through a one-pot process. The operation is simple, the reaction environment and conditions are mild, and the yield of the final product is high.

[0028] (3) The polynitrogen azole selenium prepared by the present invention has a better vulcanization accelerating effect as a rubber additive than the existing commonly used vulcanization accelerator M, and its anti-thermal oxidative aging effect is better than the commonly used comprehensive antioxidant 4010NA. Therefore, it can significantly improve the anti-thermal oxidative aging performance of the material, can stably exert the anti-aging effect for a long time, and has the advantage of reducing the amount of other additives used. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The vulcanization curves of the rubber compounds prepared in Examples 4 to 6 and Comparative Examples 1 to 2 are shown.

[0030] Figure 2 The stress-strain curves of the rubber compounds prepared in Examples 4 to 6 and Comparative Examples 1 to 2 are shown.

[0031] Figure 3 The tensile strength retention curve of the rubber compounds prepared in Examples 4 to 6 and Comparative Examples 1 to 2 is shown.

[0032] Figure 4 The graph is a retention rate curve of elongation at break of the rubber compounds prepared in Examples 4 to 6 and Comparative Examples 1 to 2.

[0033] Figure 5 This is the infrared spectrum of the polynitrogen selenium azoles prepared in Examples 1 to 3.

[0034] Figure 6 This is the DSC thermal analysis curve of the polynitrogen selenium azole prepared in Examples 1 to 3.

[0035] Figure 7TG thermal analysis curves of the polynitrogen selenium azoles prepared in Examples 1 to 3. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is further described below in conjunction with examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. If the manufacturer of the reagents or instruments used is not indicated, they are deemed to be conventional products that can be purchased commercially.

[0037] Example 1

[0038] 1g of selenium dioxide (0.0090mol) was dissolved in 50mL of anhydrous ethanol, and then 3.82g of 3-mercapto-1,2,4-triazole (0.0378mol) was dissolved in 50mL of anhydrous ethanol; then the ethanol solution of selenium dioxide was added dropwise to the ethanol solution of 3-mercapto-1,2,4-triazole, and the reaction was continued for 6 hours under the conditions of heating at 45°C and stirring at 500rpm; after the reaction was completed, the precipitate was filtered, dried, and crushed to generate a purple-brown precipitate, and the multifunctional rubber additive triazole selenium (TASe) was obtained. The yield of the obtained product was 88%, the melting point of the product was 225.9°C, and the decomposition temperature was 289.2°C.

[0039] Example 2

[0040] 1.1g of selenium dioxide (0.0099mol) was dissolved in 50mL of anhydrous ethanol, and 4.71g of 5-mercapto-1-methyltetrazolyl (0.0406mol) was dissolved in 55mL of anhydrous ethanol; the ethanol solution of selenium dioxide was then added dropwise to the ethanol solution of 5-mercapto-1-methyltetrazolyl, and the reaction was continued for 5.5h under the conditions of heating at 48°C and stirring at 550rpm; after the reaction was completed, the precipitate was filtered, dried, and crushed to generate a light yellow precipitate, and the multifunctional rubber additive methyltetrazolyl selenium (MTASe) was obtained. The yield of the obtained product was 82%, the melting point of the product was 109.6°C, and the decomposition temperature was 257.1°C.

[0041] Example 3

[0042] 1.2g of selenium dioxide (0.0108mol) was dissolved in 50mL of anhydrous ethanol, and 7.70g of 5-mercapto-1-phenyltetrazolyl (0.0432mol) was dissolved in 60mL of anhydrous ethanol; the ethanol solution of selenium dioxide was then added dropwise to the ethanol solution of 5-mercapto-1-phenyltetrazolyl, and the reaction was continued for 5h under the conditions of heating at 50°C and stirring at 600rpm; after the reaction was completed, the precipitate was filtered, dried, and crushed to generate a purple-black precipitate, and the multifunctional rubber additive phenyltetrazolyl selenium (PTASe) was obtained. The yield of the obtained product was 81%, the melting point of the product was 138.2°C, and the decomposition temperature was 183.9°C.

[0043] Example 4

[0044] 1.25 g of sulfur masterbatch (sulfur content: 80%), 2 g of selenium triazole (prepared in Example 1), 5 g of zinc oxide, 1 g of stearic acid, and 50 g of carbon black N550 were added to 100 g of styrene-butadiene rubber by an open mill to obtain a mixed rubber, which was recorded as SBR / TASe and vulcanized at 170° C. The vulcanization curve is shown in FIG. Figure 1 The vulcanization parameters are shown in Table 1.

[0045] Example 5

[0046] 1.25 g of sulfur masterbatch (sulfur content: 80%), 2 g of methyltetrazolyl selenium (prepared in Example 2), 5 g of zinc oxide, 1 g of stearic acid, and 50 g of carbon black N550 were added to 100 g of styrene-butadiene rubber by an open mill to obtain a mixed rubber, which was recorded as SBR / MTASe and vulcanized at 170° C. The vulcanization curve is shown in FIG. Figure 1 The vulcanization parameters are shown in Table 1.

[0047] Example 6

[0048] 1.25 g of sulfur masterbatch (sulfur content: 80%), 2 g of phenyltetrazolyl selenium (prepared in Example 3), 5 g of zinc oxide, 1 g of stearic acid, and 50 g of carbon black N550 were added to 100 g of styrene-butadiene rubber by an open mill to obtain a mixed rubber, which was recorded as SBR / PTASe and vulcanized at 170° C. The vulcanization curve is shown in FIG. Figure 1 The vulcanization parameters are shown in Table 1.

[0049] Comparative Example 1

[0050] 1.25 g of sulfur masterbatch (sulfur content: 80%), 2 g of accelerator M (purchased from Dongguan Siqi Rubber Technology Co., Ltd.), 5 g of zinc oxide, 1 g of stearic acid, 1 g of antioxidant 4010NA, and 50 g of carbon black N550 were added to 100 g of styrene butadiene rubber by an open mill to obtain a mixed rubber, recorded as SBR / M / 4010NA, which was vulcanized at 170°C. The vulcanization curve is shown in FIG. Figure 1The vulcanization parameters are shown in Table 1.

[0051] Comparative Example 2

[0052] 1.25 g of sulfur masterbatch (sulfur content: 80%), 2 g of accelerator NS (purchased from Dongguan Siqi Rubber Technology Co., Ltd.), 5 g of zinc oxide, 1 g of stearic acid, 1 g of antioxidant 4010NA, and 50 g of carbon black N550 were added to 100 g of styrene-butadiene rubber by an open mill to obtain a mixed rubber, recorded as SBR / NS / 4010NA, which was vulcanized at 170°C. The vulcanization curve is shown in FIG. Figure 1 The vulcanization parameters are shown in Table 1.

[0053] The vulcanization parameters of the rubber compounds obtained in Examples 4 to 6 and Comparative Examples 1 to 2 are shown in Table 1. Figure 1 The vulcanization curves of the rubber compounds obtained in Examples 4 to 6 and Comparative Examples 1 to 2 are shown in Table 1. Figure 1 It can be seen that within 2 minutes of the initial vulcanization, the vulcanization speed of polynitrogen selenium azole is faster than that of accelerator M and is similar to that of accelerator NS. However, the vulcanization speed slows down after 2 minutes, the time to reach the positive vulcanization point is longer, and the maximum torque is higher than that of accelerator M and accelerator NS. From the above results, it can be seen that the multifunctional rubber additive polynitrogen selenium azole prepared by the present invention has a certain vulcanization efficiency, and has vulcanization characteristics of short scorch time and long positive vulcanization time. The overall vulcanization performance is slightly better than that of accelerator M, and the final vulcanization degree is higher than that of accelerator NS.

[0054] Table 1 Vulcanization parameters of the rubber compounds obtained in Examples 4 to 6 and Comparative Examples 1 to 2

[0055]

[0056] The physical property parameters of the rubber compounds obtained in Examples 4 to 6 and Comparative Examples 1 to 2 are shown in Table 2. Figure 2 The tensile curves of the rubber compounds obtained in Examples 4 to 6 and Comparative Examples 1 to 2 are shown in Table 2. Figure 2It can be seen that the tensile strength of SBR / MTASe and SBR / PTASe vulcanizates is enhanced by 39.2% compared with SBR / M / 4010NA, and is enhanced by 33.3% compared with SBR / NS / 4010NA. The elongation at break of SBR / MTASe and SBR / PTASe vulcanizates is lower than that of SBR / M / 4010NA, but is enhanced by 25.2% compared with SBR / NS / 4010NA. The crosslinking density of the vulcanizate of polynitrogen selenium azoles is increased by 65.4%-72.8% compared with SBR / M / 4010NA, which is similar to or slightly higher than SBR / NS / 4010NA. From the above results, it can be seen that the multifunctional rubber additive polynitrogen selenium azoles prepared by the present invention can effectively improve the tensile strength, elongation at break and crosslinking density of rubber, which means that the mechanical properties of rubber are comprehensively improved.

[0057] Table 2 Physical property parameters of the rubber compounds obtained in Examples 4 to 6 and Comparative Examples 1 to 2

[0058]

[0059] The thermal oxidation aging properties of the rubber compounds obtained in Examples 4 to 6 and Comparative Examples 1 to 2 are shown in Table 3. Figure 3 The tensile strength retention curve of the rubber compounds prepared in Examples 4 to 6 and Comparative Examples 1 to 2 is shown in FIG. Figure 4 The elongation at break retention curves of the rubber compounds prepared in Examples 4 to 6 and Comparative Examples 1 to 2 are shown in Table 3. Figure 3 and Figure 4 It can be seen that: when aged for 48-96 hours, the heat-oxidative aging resistance of the vulcanized rubber containing polynitrogen selenium is similar to or slightly better than that of the vulcanized rubber containing the antioxidant 4010NA; when aged for 144-192 hours, the heat-oxidative aging resistance of the vulcanized rubber containing polynitrogen selenium has a significant advantage over the vulcanized rubber containing the antioxidant 4010NA, with a significant gap of 10%-15%. From the above results, it can be seen that the polynitrogen selenium prepared by the present invention has a longer-term heat-oxidative aging resistance and can stably exert an anti-aging effect in rubber for a long time.

[0060] Table 3 Thermal oxidative aging properties of the rubber compounds obtained in Examples 4 to 6 and Comparative Examples 1 to 2

[0061]

[0062]

[0063] The infrared spectra of the polynitrogen azole selenium prepared in Examples 1 to 3 of the present invention are as follows: Figure 5 As shown, from Figure 5 It can be seen that for TASe, 3080cm- 1It is the absorption peak of NH bond, 1533cm- 1 It is the absorption peak of C=N bond, 1232cm- 1 It is the absorption peak of CN bond, 998cm- 1 is the absorption peak of CS bond. For MTASe, 1383cm- 1 It is the absorption peak of the CH bond of the methyl group, 1171cm- 1 It is the absorption peak of CN bond, 1021cm- 1 is the absorption peak of CS bond. For PTASe, 1593cm- 1 、1494cm- 1 、1405cm- 1 It is the absorption peak of the benzene ring skeleton, 1226cm- 1 It is the absorption peak of CN bond, 1014cm- 1 It is the absorption peak of CS bond, 764cm- 1 The above data prove that the present invention synthesizes a product with a target structure.

[0064] The DSC thermal analysis curves of the polynitrogen selenium azoles prepared in Examples 1 to 3 of the present invention are as follows: Figure 6 Its TG thermal analysis curve is shown in Figure 7 As shown. Figure 6 and Figure 7 It can be seen that the melting point of TASe is 225.9°C and the decomposition temperature is 289.2°C; the melting point of MTASe is 109.6°C and the decomposition temperature is 257.1°C; the melting point of PTASe is 138.2°C and the decomposition temperature is 183.9°C. In addition, the curves of polynitrogen selenium have only one sharp endothermic peak and one thermal weight loss step, indicating that the obtained product has a high purity.

[0065] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a multifunctional rubber additive polynitrogen selenium azole, characterized in that: The steps include: Selenium dioxide and polyazole ligands are dissolved in anhydrous ethanol respectively, and then the ethanol solution of selenium dioxide is added dropwise to the ethanol solution of polyazole ligands under heating and stirring conditions, and the reaction is continued to obtain a solid precipitate, which is filtered, washed and dried to obtain the multifunctional rubber additive polyazole selenium; the polyazole ligand is selected from one or more of 3-mercapto-1,2,4-triazole, 5-mercapto-1-methyltetrazolyl, and 5-mercapto-1-phenyltetrazolyl.

2. The method for preparing the multifunctional rubber additive polynitrogen selenium azole according to claim 1, characterized in that: The molar ratio of selenium dioxide to polyazole ligand is 1:(4.0-4.2).

3. The preparation method of the multifunctional rubber additive polynitrogen selenium azole according to claim 1, characterized in that: The temperature of the heating condition is 45-50° C., and the stirring rate of the stirring condition is 500-600 rpm.

4. The method for preparing the multifunctional rubber additive polynitrogen selenium azole according to claim 1, characterized in that: The concentration of the selenium dioxide ethanol solution is 0.020-0.024 g / mL.

5. The method for preparing the multifunctional rubber additive polynitrogen selenium azole according to claim 1, characterized in that: The concentration of the polyazole ligand ethanol solution is 0.076-0.128 g / mL.

6. The method for preparing the multifunctional rubber additive polynitrogen selenium azole according to claim 1, characterized in that: The volume ratio of the selenium dioxide ethanol solution to the polyazole ligand ethanol solution is 1:(1-1.2).

7. The method for preparing the multifunctional rubber additive polynitrogen selenium azole according to claim 1, characterized in that: The continuous reaction is carried out at a heating temperature of 45-50° C. and a stirring speed of 500-600 rpm for 5-6 hours.

Images