A process for the preparation of a vulcanizing agent based on methyl oleate

Abstract

The present application relates to a kind of preparation methods of methyl oleate-based vulcanizing agent.The preparation method of the present application includes the following processes:(1) methyl oleate and part of sulfur powder are reacted to obtain vulcanized methyl oleate in the presence of dithiol;(2) another part of sulfur powder is mixed with vulcanized methyl oleate to obtain a methyl oleate-based vulcanizing agent.The methyl oleate-based vulcanizing agent prepared by the method of the present application can improve the modification efficiency of modified asphalt as a stabilizer for asphalt modification,reduce the time required for modification while meeting the requirements of modified asphalt penetration and softening point,and the method of the present application reduces the vulcanization temperature to a certain extent,with lower energy consumption.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of asphalt additives, and particularly relates to a preparation method of a modified asphalt vulcanization stabilizer based on methyl oleate. BACKGROUND

[0002] SBS (styrene-butadiene-styrene block copolymer) modified asphalt is a commonly used polymer modified asphalt, which has excellent high and low temperature performance and is widely used in the construction of various grades of pavement, especially high-speed pavement. However, SBS in SBS modified asphalt is only physically mixed with asphalt, which is easy to segregate under high temperature, thereby causing the performance of pavement to decrease. Therefore, various additives are usually added in the preparation process of SBS modified asphalt to promote the compatibility of polymer and asphalt. Sulfur is a commonly used stabilizer for polymer modified asphalt. After high-temperature vulcanization, SBS forms a network structure in asphalt, which makes the strength of modified asphalt greater, the dispersion more uniform, and the mixed structure with asphalt more stable, so as to effectively improve the storage of modified asphalt and the stability of pavement mixed with the modified asphalt. However, due to the high viscosity of asphalt, especially during on-site construction, it is difficult to add sulfur in small amounts for multiple times in a short time. In order to achieve the expected effect of the stabilizer, it is necessary to increase the shearing time or improve the shearing temperature, which affects the construction efficiency.

[0003] Methyl oleate, as a high-carbon fatty acid ester, has the characteristics of high flash point, good compatibility with asphalt and SBS, and good plasticizing effect, and can be used as a functional additive for asphalt. When methyl oleate and sulfur powder are simultaneously added to asphalt, part of the sulfur powder reacts with the double bond on the methyl oleate to form organic sulfide-vulcanized methyl oleate, which is beneficial to the plasticizing effect of SBS. However, due to the modification temperature of asphalt during on-site construction being 165-180℃, the reaction of sulfur powder with methyl oleate usually requires heating to 160-200℃, and the dispersion effect of sulfur powder in asphalt needs to be improved, so the efficient reaction of methyl oleate with sulfur powder is impossible, and the performance improvement of modified asphalt is limited. If a mixed system of vulcanized methyl oleate and sulfur powder is directly used as an asphalt additive, not only the problem of insufficient reaction caused by the construction temperature of asphalt being lower than the reaction temperature of methyl oleate and sulfur powder can be avoided, but also the vulcanized methyl oleate can act as a dispersant for sulfur powder, increase the solubility of sulfur powder in methyl oleate, facilitate the uniform mixing of sulfur powder with asphalt, and play a plasticizing effect on SBS.

[0004] However, there is no related report on the mixed system of vulcanized methyl oleate and sulfur powder being used as an asphalt additive added to the asphalt base material before construction. Vulcanized methyl ester is often used as a functional component of lubricating oil base oil and metal processing fluid, and the method of using sulfur to perform vulcanization reaction to obtain vulcanized methyl ester is not suitable for the asphalt industry.

[0005] The metal processing fluid additive and its preparation method disclosed in Chinese patent CN111793515A, the inventors use lard, cottonseed oil mixed with methyl oleate, and then react with sulfur to produce a metal processing fluid, the reaction temperature is 160-170℃, but the oil and fat used in this method has poorer compatibility with asphalt than methyl oleate, and in this method, triethanolamine is used as a functional additive, which also has poor compatibility with asphalt, and when applied to the asphalt industry, the segregation is serious.

[0006] The vulcanized methyl oleate and its preparation method and application disclosed in Chinese patent CN115594619B, the inventors mix sulfur, hydrogen sulfide and organic amine, then add methyl oleate for mixing, reaction and distillation to produce, this process uses hydrogen sulfide as a mixed vulcanizing agent, which is not suitable for the asphalt industry.

[0007] Therefore, it is necessary to develop a preparation method of a vulcanization stabilizer based on methyl oleate suitable for the asphalt industry to achieve the purpose of directly using a mixed system of vulcanized methyl oleate and sulfur powder as an asphalt additive to improve the performance of modified asphalt. SUMMARY

[0008] The purpose of the present application is to provide a preparation method of a vulcanization stabilizer based on methyl oleate suitable for the asphalt industry.

[0009] To achieve the above purpose, the technical solution adopted by the present application is:

[0010] A preparation method of a vulcanization stabilizer based on methyl oleate, the preparation method comprising the following steps:

[0011] (I) reacting methyl oleate and part of sulfur powder in the presence of a dithiol to obtain vulcanized methyl oleate;

[0012] (II) mixing another part of sulfur powder with the vulcanized methyl oleate to obtain the vulcanization stabilizer based on methyl oleate.

[0013] Preferably, in the step (I), the dithiol is 1,6-hexanedithiol and / or 1,4-butanedithiol.

[0014] According to some embodiments, when 1,6-hexanedithiol and 1,4-butanedithiol are used at the same time, the mass ratio of the two is (0.8-1.2):1, and most preferably 1:1.

[0015] Preferably, in the step (I), the temperature of the reaction is 120-150℃.

[0016] Further preferably, in the step (I), the temperature of the reaction is 120-140℃.

[0017] Preferably, in step (a), the reaction time is 1 hour to 3 hours.

[0018] More preferably, in step (a), the reaction time is 1.5h to 2.5h.

[0019] Preferably, in step (ii), the mixing temperature is 110℃~130℃.

[0020] More preferably, in step (ii), the mixing temperature is 120℃~130℃.

[0021] Preferably, in step (a), the methyl oleate is derived from soybean oil, corn oil or rapeseed oil, and the iodine value of the methyl oleate is ≤120g I2 / 100g.

[0022] Preferably, the sulfur powder has a particle size of 60-100 mesh.

[0023] Preferably, in step (a), the amount of sulfur powder used is 8 wt% to 10 wt% of the methyl oleate.

[0024] Preferably, in step (a), the amount of dithiol used is 5 wt% to 10 wt% of the methyl oleate.

[0025] Preferably, in step (ii), the amount of the other part of the sulfur powder is 8wt% to 10wt% of the methyl oleate.

[0026] According to some specific and preferred embodiments, the amount of sulfur powder used in step (I) is equal to the amount of sulfur powder used in another part of step (II).

[0027] According to some specific embodiments, the preparation method of the methyl oleate-based vulcanizing agent includes the following specific steps:

[0028] Step 1: Mix methyl oleate and a portion of sulfur powder at 60 rpm until homogeneous to obtain a suspension;

[0029] Step 2: Mix the suspension from Step 1 with dithiol at a speed of 60 rpm;

[0030] Step 3; Continue stirring while slowly heating to 120℃;

[0031] Step 4: Continue heating to 140℃~150℃, and maintain the temperature at 140℃~150℃ for 1h~3h.

[0032] Step 5: Mix the product from Step 4 with another portion of sulfur powder at 110℃~130℃ and stir until the sulfur powder is evenly dispersed.

[0033] This invention uses dithiol as an addition agent for the double bond structure of sulfur powder and methyl oleate, which reduces the reaction conditions of methyl oleate sulfurization, allowing the reaction to begin at 120°C. At the same time, the reaction product, methyl oleate sulfurization, increases the viscosity of the product after the reaction, providing conditions for the stable dispersion of the insoluble sulfur powder. In addition, according to the principle of like compatibility, it also increases the dispersion of sulfur powder in methyl oleate sulfurization.

[0034] The present invention also provides a methyl oleate-based sulfur stabilizer prepared by the preparation method described above.

[0035] The present invention also provides the application of the above-mentioned methyl oleate-based vulcanization stabilizer in asphalt modification.

[0036] Using the methyl oleate-based sulfurization stabilizer of this invention as an asphalt additive can not only accelerate the uniform dispersion speed of the sulfurization stabilizer during the production of modified asphalt, thereby improving the processing efficiency of modified asphalt, but also achieve better plasticizing effect after construction, further improving the anti-aging performance of modified asphalt.

[0037] The present invention also provides a modified asphalt, the modified asphalt comprising base asphalt, SBS, the above-mentioned methyl oleate-based vulcanization stabilizer and modified co-solvent.

[0038] According to some specific embodiments, the modified co-solvent is industrial grease 1031D.

[0039] According to some specific implementation methods, the base asphalt is GB 70.

[0040] Preferably, the methyl oleate-based vulcanization stabilizer is added in an amount of 0.1% to 0.3% of the mass of the base asphalt, based on the mass of sulfur.

[0041] More preferably, the methyl oleate-based vulcanization stabilizer is added in an amount of 0.15% to 0.25% of the mass of the base asphalt, based on the mass of sulfur.

[0042] Preferably, the amount of SBS used is 4% to 6% of the mass of the base bitumen.

[0043] Preferably, the amount of the modified co-solvent is 1% to 3% of the mass of the base asphalt.

[0044] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0045] The methyl sulfate-based sulfuric acid stabilizer prepared by the method of this invention can improve the modification efficiency of modified asphalt when used as a stabilizer for asphalt modification. While meeting the requirements for penetration and softening point of modified asphalt, it reduces the modification time required. At the same time, the method of this invention reduces the reaction temperature to a certain extent, resulting in lower energy consumption. Attached Figure Description

[0046] Figure 1 The diagram shows the state of the methyl oleate-based vulcanizing agents of Example 1 and Comparative Examples 1 and 2 (from left to right: Comparative Example 1, Comparative Example 2, and Example 1). Detailed Implementation

[0047] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific applications, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0048] The technical solution of the present invention will be further described below with reference to embodiments and comparative examples.

[0049] The methyl oleate used in the following examples and comparative examples was purchased from Suzhou Fengbei Biotechnology Co., Ltd. (methyl oleate 1192), with an iodine value ≤120g I2 / 100g.

[0050] The sulfur powder used in the following examples and comparative examples has a particle size of 60-100 mesh.

[0051] Example 1

[0052] This embodiment provides a method for preparing a vulcanizing agent based on methyl oleate, which includes the following steps:

[0053] Step 1: Add 100 parts of methyl oleate and 10 parts of sulfur powder to the reaction vessel and stir at 60 rpm for half an hour.

[0054] Step 2: Add 5 parts of 1,6-hexanedithiol to the reaction vessel and continue stirring for 10 minutes.

[0055] Step 3: Control the heating efficiency to 10℃ / 10 minutes, heat to 120℃, and continue stirring while heating.

[0056] Step 4: Continue heating to 140℃ and maintain the temperature at 140℃ for 2 hours.

[0057] Step 5: Add 10 parts of sulfur powder to the reaction vessel, keep it at 120°C and stir at 60 rpm for half an hour. The product is brown and slightly transparent, with no visible sulfur droplets. After cooling to room temperature, the product is the desired methyl oleate-based vulcanizing agent.

[0058] Example 2

[0059] This embodiment provides a method for preparing a vulcanizing agent based on methyl oleate, which includes the following steps:

[0060] Step 1: Add 100 parts of methyl oleate and 10 parts of sulfur powder to the reaction vessel and stir at 60 rpm for half an hour.

[0061] Step 2: Add 5 parts of 1,4-butanedithiol to the reaction vessel and continue stirring for 10 minutes.

[0062] Step 3: Control the heating efficiency to 10℃ / 10 minutes, heat to 120℃, and continue stirring while heating.

[0063] Step 4: Continue heating to 140℃ and maintain the temperature at 140℃ for 2 hours.

[0064] Step 5: Add 10 parts of sulfur powder to the reaction vessel, keep it at 120°C and stir at 60 rpm for half an hour. The product is brown and slightly transparent, with no visible sulfur droplets. After cooling to room temperature, the product is the desired methyl oleate-based vulcanizing agent.

[0065] Example 3

[0066] This embodiment provides a method for preparing a vulcanizing agent based on methyl oleate, which includes the following steps:

[0067] Step 1: Add 100 parts of methyl oleate and 10 parts of sulfur powder to the reaction vessel and stir at 60 rpm for half an hour.

[0068] Step 2: Add 2.5 parts of 1,6-hexanedithiol and 2.5 parts of 1,4-butanedithiol to the reaction vessel and continue stirring for 10 minutes.

[0069] Step 3: Control the heating efficiency to 10℃ / 10 minutes, heat to 120℃, and continue stirring while heating.

[0070] Step 4: Continue heating to 140℃ and maintain the temperature at 140℃ for 2 hours.

[0071] Step 5: Add 10 parts of sulfur powder to the reaction vessel, keep it at 120°C and stir at 60 rpm for half an hour. The product is brown and slightly transparent, with no visible sulfur droplets. After cooling to room temperature, the product is the desired methyl oleate-based vulcanizing agent.

[0072] Comparative Example 1

[0073] This comparative example provides a method for preparing a vulcanizing agent based on methyl oleate, which includes the following steps:

[0074] Step 1: Add 100 parts of methyl oleate and 10 parts of sulfur powder to the reaction vessel and stir at 60 rpm for half an hour.

[0075] Step 2: Control the heating efficiency to 10℃ / 10 minutes, heat to 120℃, and continue stirring while heating.

[0076] Step 3: Heat to 140℃ and maintain the temperature at 140℃ for 2 hours.

[0077] Step 4: Add 10 parts of sulfur powder to the reaction vessel, keep it at 120°C and stir for half an hour. The product is light brown and a large number of yellow sulfur droplets are visible to the naked eye. Continue to keep it at the temperature and stir for half an hour, then cool it to room temperature. There are still a large number of sulfur powder particles that are visible to the naked eye.

[0078] Comparative Example 2

[0079] This comparative example provides a method for preparing a vulcanizing agent based on methyl oleate, which includes the following steps:

[0080] Step 1: Add 100 parts of methyl oleate and 10 parts of sulfur powder to the reaction vessel and stir at 60 rpm for half an hour.

[0081] Step 2: Control the heating efficiency to 10℃ / 10 minutes, heat to 120℃, and continue stirring while heating.

[0082] Step 3: Heat to 180℃ and maintain the temperature for 2 hours.

[0083] Step 4: Add 10 parts of sulfur powder to the reaction vessel, keep it at 120°C and stir for half an hour. The product is dark brown with yellow-brown sulfur particles suspended in the air.

[0084] Performance testing as a modified asphalt additive:

[0085] The methyl oleate-based vulcanizing agents of the above examples and comparative examples were mixed with base asphalt (National Standard No. 70), SBS (Sinopec Baling Petrochemical Synthetic Rubber SBS YH-815), and modified co-solvent (Industrial Oil 1031D of Suzhou Fengbei Biotechnology Co., Ltd.). The methyl oleate-based vulcanizing agent was added at a rate of 0.2% of the mass of sulfur powder to the mass of base asphalt, SBS was added at a rate of 4.8% of the mass of base asphalt, and the modified co-solvent was added at a rate of 1.8% of the mass of base asphalt. Asphalt was modified using conventional methods in the field by holding it at 180℃ for 2 hours. After modification, the penetration index (referring to GB / T 4509-2010 Asphalt Penetration Test Method) and softening point index (referring to T0606-2000 Asphalt Softening Point Test (Ring and Ball Method)) of the modified asphalt were tested. Performance was compared with modified asphalt using a mixture of sulfur powder and methyl oleate (mass ratio of sulfur powder to methyl oleate 100:20) instead of the methyl oleate-based vulcanizing agent. The mixture of sulfur powder and methyl oleate was added at a sulfur content of 0.2% of the mass of the base asphalt.

[0086] The surface appearance of the modified asphalt samples after cooling to room temperature was observed. See Table 1 for details.

[0087] Table 1

[0088] Modified asphalt sample number Vulcanizing agent Surface appearance 1# Example 1 Smooth, no small particle protrusions 2# Example 2 Smooth, no small particle protrusions 3# Example 3 Smooth, no small particle protrusions 4# Comparative example 1 With slight small particle protrusions 5# Comparative example 2 Without small particle protrusions 6# Sulfur powder With small particle protrusions

[0089] The results of the penetration and softening point tests are shown in Table 2:

[0090] Table 2

[0091] Modified asphalt sample number Penetration at 25°C (μm) Softening point (°C) 1# 52 83 2# 53 85 3# 53 85 4# 48 76 5# 50 79 6# 46 74

[0092] The above results show that the use of dithiol as an addition agent for the double bond structure of sulfur powder and methyl oleate in this invention not only reduces the reaction conditions of sulfurized methyl oleate, allowing the reaction to begin at 120°C, but also increases the viscosity of the product after the reaction, providing conditions for the stable dispersion of the insoluble sulfur powder. Furthermore, based on the principle of like dissolves like, it also increases the solubility of sulfur powder in sulfurized methyl oleate. The methyl sulfate-based sulfurization stabilizer of this invention, as an asphalt additive, can effectively improve the penetration and softening point of modified asphalt, thereby increasing the production efficiency of modified asphalt.

[0093] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.

Claims

1. A process for the preparation of a vulcanization stabilizer based on methyl oleate, characterized in that: The preparation method comprises the following steps: (1) reacting methyl oleate and part of sulfur powder in the presence of a dithiol to obtain sulfurized methyl oleate, wherein the dithiol is 1,6-hexanedithiol and / or 1,4-butanedithiol, the amount of the part of sulfur powder is 8wt%-10wt% of the methyl oleate, and the amount of the dithiol is 5wt%-10wt% of the methyl oleate; (2) mixing another part of sulfur powder with the sulfurized methyl oleate to obtain the methyl oleate-based vulcanization stabilizer, wherein the amount of the another part of sulfur powder is 8wt%-10wt% of the methyl oleate.

2. The process for the preparation of methyl oleate based vulcanizing agents according to claim 1, characterized in that: In the step (1), the temperature of the reaction is 120°C-150°C; And / or, in the step (1), the time of the reaction is 1h-3h; And / or, in the step (2), the temperature of the mixing is 110°C-130°C.

3. The process for the preparation of methyl oleate based vulcanizing agents according to claim 1, characterized in that: In the step (1), the methyl oleate is derived from soybean oil, corn oil or rapeseed oil, and the iodine value of the methyl oleate is ≤120g I2 / 100g; And / or, the particle size of the sulfur powder is 60-100 mesh.

4. The process for the preparation of methyl oleate based vulcanizing agents according to claim 1, characterized in that: The amount of the part of sulfur powder in the step (1) is equal to the amount of the another part of sulfur powder in the step (2).

5. The methyl oleate-based vulcanization stabilizer prepared by the preparation method in any one of claims 1-4.

6. The use of the methyl oleate-based vulcanization stabilizer in claim 5 in asphalt modification.

7. A modified bitumen characterized in that, The modified asphalt comprises base asphalt, SBS, the methyl oleate-based vulcanization stabilizer in claim 5 and a modified cosolvent.

8. The modified bitumen of claim 7, wherein, The amount of the methyl oleate-based vulcanization stabilizer in claim 5 is added in an amount of 0.1%-0.3% of the mass of sulfur powder in the raw material based on the mass of the base asphalt.

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