A method for preparing a polystyrene in-situ reinforced 1,2-polybutadiene rubber product and application

Abstract

The application belongs to the field of rubber modification, and discloses a preparation method of polystyrene in-situ reinforced 1,2-polybutadiene rubber, a product and application. The preparation method comprises the following steps: (1) under a protective atmosphere, a styrene solution is subjected to a polymerization reaction in the presence of a first molybdenum catalyst to obtain a mixture containing polystyrene; (2) the mixture containing polystyrene is mixed with a second solvent, butadiene and a second molybdenum catalyst, and subjected to a second polymerization reaction under a protective atmosphere to obtain in-situ blended polystyrene / 1,2-polybutadiene rubber. The mechanical strength of the modified rubber is obviously improved, the Mooney viscosity is low, the processing performance is better, the molecular weight is high, the content of 1,2 structure is high, the wet skid resistance, heat generation and rolling resistance performance of the rubber are improved, the rubber is suitable for tires and products, the application range of 1,2-polybutadiene rubber is further widened, and the rubber has extremely high application value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of rubber modification, especially relates to the field of in-situ reinforced modified 1,2-polybutadiene rubber, and particularly relates to a preparation method of polystyrene in-situ reinforced 1,2-polybutadiene rubber, a product and application. BACKGROUND

[0002] 1,2-polybutadiene rubber (also known as high-vinyl polybutadiene rubber, abbreviated as HVBR) is a non-polar rubber, the main chain is a saturated alkane chain, and a large number of side vinyl groups (vinyl content is greater than 65%) are contained in the side chain, has excellent properties of high wet skid resistance, low heat build-up and low rolling resistance, and if used in combination with other rubbers such as natural rubber, can be used as a tread rubber of a high-performance green tire, and meanwhile, the rich side vinyl groups improve the relaxation and internal friction of the HVBR molecular chain, and compared with natural rubber, styrene-butadiene rubber and cis-butadiene rubber, the glass transition temperature of the HVBR is closer to room temperature and the loss factor value is higher, and the HVBR can be used as a damping material. However, compared with other synthetic rubbers, the physical and mechanical properties of the HVBR are not outstanding, and after the HVBR is reinforced by fillers such as carbon black and white carbon black, the mechanical properties can be greatly improved, but the mechanical strength is still lower than that of natural rubber and styrene-butadiene rubber after the fillers are used for reinforcement, and therefore, if the mechanical strength of the HVBR can be further improved, the application of the HVBR in tires and products can be expanded.

[0003] In addition to reinforcing the rubber by using fillers, the rubber can also be blended with plastics to improve the mechanical properties. For example, Wuhu Xin Hai Rubber and Plastic Products Co., Ltd. has invented a kind of NBR / PVC blended rubber and plastic material and a preparation method thereof (CN102993500A, application number CN201210399734.2), the NBR / PVC blended rubber and plastic material has the ozone resistance of PVC and the oil resistance and cross-linking property of NBR, and improves the mechanical properties such as tensile strength, tensile stress and tear resistance of the original material. At present, there is no research on improving the mechanical properties of HVBR by rubber and plastic blending, and the HVBR contains rich side vinyl groups and has large Mooney viscosity, and the processing performance of the HVBR is poor, and it is difficult to physically blend and process the HVBR with plastics, and the dispersibility is poor and it is difficult to achieve ideal effects.

[0004] Qingdao University of Science and Technology has invented a kind of HVBR blended in-situ with industrial ethylene-vinyl acetate rubber (CN105777964A, application number CN201610147275.7), and a two-phase polymer molecularly blended material is prepared, and the compatibility of the two phases is obviously improved, and the damping performance of the polymer blend is improved. However, it is found by the inventors of the present application that the rubber or plastic produced industrially generally contains residual catalyst or other impurities, which can poison the molybdenum catalyst and affect the polymerization activity, and limit the industrial production.

[0005] A method for preparing high vinyl butadiene-styrene copolymer using molybdenum catalyst system is invented by China Petroleum Chemical Corporation (CN106699967A, application number CN201510780995.2), but the molybdenum butadiene-styrene rubber obtained by this method has low molecular weight, wide molecular weight distribution, and large compression heat generation, and can only be used as a modifier for high-performance tire tread rubber, high-impact polystyrene, ABS and other high-performance plastics.

[0006] In summary, the physical and mechanical properties of conventional 1,2 polybutadiene rubber need to be further improved, but either the 1,2 polybutadiene rubber has high Mooney viscosity, poor processing performance itself, and it is difficult to physically blend with plastics, and the dispersion is poor and it is difficult to achieve the desired effect; or the in-situ blending polymerization activity is low, it is difficult to use an efficient method to in-situ reinforce rubber or plastic with 1,2 polybutadiene rubber, and it is not suitable for industrial production; or the obtained rubber has low molecular weight or wide molecular weight distribution, and can only be used as a modifier for tires and products. SUMMARY

[0007] To overcome the above-mentioned defects of the prior art, the inventors of the present application have found, through research, that the preparation method of polystyrene in-situ reinforced 1,2-polybutadiene rubber (HVBR) of the present application can obtain polystyrene in-situ reinforced 1,2-polybutadiene rubber (HVBR) by synthesizing polystyrene with a molybdenum catalyst, obtaining a polymerization system, directly blending the polymerization system with butadiene monomer, and adding a molybdenum catalyst to prepare polystyrene in-situ blended HVBR. The mechanical strength of the polystyrene in-situ reinforced 1,2-polybutadiene rubber is significantly improved, and has a lower Mooney viscosity and better processing performance. Furthermore, the polystyrene in-situ reinforced 1,2-polybutadiene rubber has a higher molecular weight, a higher content of 1,2 structure, and improved wet skid resistance, heat generation and rolling resistance performance. The rubber is suitable for tires and products, further broadening the application range of 1,2-polybutadiene rubber, and has extremely high application value.

[0008] The first aspect of the present application provides a preparation method of polystyrene in-situ reinforced 1,2-polybutadiene rubber, comprising:

[0009] (1) under a protective atmosphere, a styrene solution is subjected to a first polymerization reaction in the presence of a first molybdenum catalyst to obtain a mixture containing polystyrene;

[0010] (2) the mixture containing polystyrene obtained in step (1) is mixed with a second solvent, butadiene and a second molybdenum catalyst, and subjected to a second polymerization reaction under a protective atmosphere to obtain in-situ blended polystyrene / 1,2-polybutadiene rubber;

[0011] The first molybdenum catalyst and the second molybdenum catalyst each comprise a molybdenum compound, an alkyl aluminum and a phosphate ester.

[0012] The present application is based on the preparation of HVBR catalyzed by a molybdenum catalyst, polystyrene is prepared by using a molybdenum catalyst, and then butadiene and a molybdenum catalyst are added to the polymerization system to prepare in-situ reinforced HVBR of styrene.

[0013] According to the present application, the molar ratio of the styrene, the molybdenum compound, the alkyl aluminum and the phosphate ester can be selected in a wide range, and in a preferred embodiment of the present application, in step (1), the molar ratio of the styrene, the molybdenum compound, the alkyl aluminum and the phosphate ester is (100-6000):1:(5-30):(1-5); preferably (1500-6000):1:(8-20):(1-3).

[0014] According to the present application, preferably, the molar ratio of the styrene to the molybdenum compound is (1500-6000):1, for example, 1500, 2000, 2500, 3000, 4000, 5000, 6000 and any two values or any interval of any two values to 1.

[0015] According to the present application, preferably, the molar ratio of the molybdenum compound to the alkyl aluminum is 1:(8-20), for example, 1 to 8, 10, 14, 16, 18, 20 and any two values or any interval of any two values.

[0016] According to the present application, preferably, the molar ratio of the molybdenum compound to the phosphate ester is 1:(1-3), for example, 1 to 1, 1.5, 2, 2.5, 3 and any two values or any interval of any two values.

[0017] According to the present application, the concentration of the styrene solution can be selected in a wide range, and in a preferred embodiment of the present application, the concentration of the styrene solution is 0.96-1.92 mol / L (i.e. M), for example, 0.96 mol / L, 1 mol / L, 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, 1.92 mol / L, and any two values or any interval of any two values.

[0018] According to the present application, the conditions of the first polymerization reaction in step (1) can be selected in a wide range, and in a preferred embodiment of the present application, the conditions of the first polymerization reaction in step (1) include: the temperature is 60-90℃, and / or the time is 8-12h.

[0019] In a preferred embodiment of the present application, the protective atmosphere is nitrogen and / or inert gas.

[0020] According to the present application, the solvent used in the styrene solution can be selected in a wide range, and in a preferred embodiment of the present application, the solvent used in the styrene solution is at least one of toluene, n-pentane, iso-pentane, n-hexane, cyclohexane, n-heptane, and n-octane.

[0021] According to the present application, the amount of the mixture containing polystyrene can be selected in a wide range, and in a preferred embodiment of the present application, the amount of the mixture containing polystyrene is such that the mass ratio of polystyrene to butadiene is (0.5-20): 100, preferably (2-15): 100, for example 2, 5, 8, 10, 13, 15, and any two values or any range of any two values to 100.

[0022] According to the present application, in step (2), the molar ratio of butadiene, molybdenum compound, alkyl aluminum, and phosphate ester can be selected in a wide range, and in a preferred embodiment of the present application, the molar ratio of butadiene, molybdenum compound, alkyl aluminum, and phosphate ester is (500-8000): 1: (5-30): (1-5), preferably (2000-6000): 1: (10-24): (2-4).

[0023] According to the present application, preferably, the molar ratio of butadiene to molybdenum compound is (2000-6000): 1, for example, 2000, 2500, 3000, 4000, 5000, 6000, and any two values or any range of any two values to 1.

[0024] According to the present application, preferably, the molar ratio of molybdenum compound to alkyl aluminum in step (2) is 1: (10-24), for example, 1 to 10, 14, 16, 18, 20, 22, 24, and any two values or any range of any two values.

[0025] According to the present application, preferably, the molar ratio of molybdenum compound to phosphate ester in step (2) is 1: (2-4), for example, 1 to 2, 2.5, 3, 3.5, 4, and any two values or any range of any two values.

[0026] According to the present application, the amount of the second solvent can be selected in a wide range, and in a preferred embodiment of the present application, the amount of the second solvent is such that the concentration of butadiene in the second solvent is 1-5 mol / L, for example, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, and any two values or any range of any two values.

[0027] According to the present application, the second solvent can be selected in a wide range, and in a preferred embodiment of the present application, the second solvent is selected from at least one of toluene, n-pentane, iso-pentane, n-hexane, cyclohexane, n-heptane, n-octane.

[0028] According to the present application, the conditions of the second polymerization reaction in step (2) can be selected in a wide range, and in a preferred embodiment of the present application, the conditions of the second polymerization reaction in step (2) include:

[0029] The temperature is 40-80℃, and / or the reaction time is 4-12h, and / or the mixing mode is stirring, preferably the stirring speed is 20-600rpm.

[0030] In a preferred embodiment of the present application, the protective atmosphere is nitrogen and / or inert gas.

[0031] According to the present application, the molybdenum compound can be selected in a wide range, and in a preferred embodiment of the present application, the molybdenum compound is selected from at least one of molybdenum pentachloride, molybdenum tetrachloride, molybdenum dichloride dioxide.

[0032] According to the present application, the alkyl aluminum can be selected in a wide range, and in a preferred embodiment of the present application, the alkyl aluminum is selected from at least one of trimethyl aluminum, tripropyl aluminum, tributyl aluminum, diisobutyl aluminum hydride, m-cresol aluminum.

[0033] According to the present application, the phosphate ester can be selected in a wide range, and in a preferred embodiment of the present application, the phosphate ester is selected from at least one of triethyl phosphate, tripropyl phosphate, tributyl phosphate, triphenyl phosphate, di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester, triisopropyl phenyl phosphate, triisooctyl phosphate.

[0034] In a preferred embodiment of the present application, the preparation method further comprises vulcanizing the in-situ blended polystyrene / 1,2-polybutadiene rubber with the auxiliary obtained in step (2) to obtain polystyrene in-situ reinforced 1,2-polybutadiene rubber.

[0035] According to the present application, the auxiliary for vulcanization can use the conventional auxiliary in the art. In a preferred embodiment of the present application, the auxiliary for vulcanization includes, in parts by mass, relative to 100 parts of the in-situ blended polystyrene / 1,2-polybutadiene rubber: 20-60 parts of carbon black, 1-3 parts of ZnO, 0.5-1.5 parts of stearic acid, 0.4-0.6 parts of accelerator, 0.4-0.8 parts of antioxidant, 0.5-2 parts of vulcanizing agent.

[0036] According to the present application, the accelerators, anti-aging agents, and vulcanizing agents are all commonly used additives in rubber, including but not limited to the types or models of the additives used in the present application.

[0037] In a preferred embodiment of the present application, the mixing step before vulcanization comprises:

[0038] The in-situ blended polystyrene / 1,2-polybutadiene rubber and the additives except for the vulcanizing agent are first mixed in an internal mixer, and then the vulcanizing agent is added to the open mill.

[0039] According to the present application, the vulcanization conditions can be selected within a wide range, and in a preferred embodiment of the present application, the vulcanization conditions include: temperature 120-160℃, and / or, time 1-60min, and / or, pressure 1-10MPa.

[0040] In order to facilitate the understanding of the present application, the following describes a preferred embodiment of the present application:

[0041] The preparation method of the polystyrene in-situ reinforced 1,2-polybutadiene rubber of the present application comprises the following steps:

[0042] (1) Under a nitrogen atmosphere, a styrene solution of a certain concentration and a molybdenum catalyst are added to a reactor, heated to 60-90℃, and reacted for 8-12h.

[0043] (2) The polystyrene solution obtained in step (1) is dissolved to a certain concentration, preferably using a solvent, under a nitrogen atmosphere, a butadiene solution is added to the polystyrene solution reactor, and then a molybdenum catalyst is added to the reactor, heated to 40-80℃, and then stirred for 4-12h at a stirring speed of 20-600rpm;

[0044] (3) The prepared polystyrene in-situ blended high-vinyl polybutadiene rubber is processed and vulcanized according to a certain formula to obtain a PS plastic / polybutadiene in-situ intercalated plastic / rubber composite (in situ-Plastic / HVBR).

[0045] On the basis of the above technical solution, preferably, the styrene concentration in step (1) is 0.96-1.92M, and the solvent used is one or more of toluene, n-pentane, isopentane, n-hexane, cyclohexane, n-heptane, and n-octane.

[0046] On the basis of the above technical solution, preferably, the solvent used in step (2) is one or two of n-pentane, isopentane, n-hexane, cyclohexane, n-heptane, and n-octane.

[0047] On the basis of the above technical solution, preferably, the mass fraction of polystyrene in butadiene in step (2) is 0.5%-20%, and the solvent of butadiene solution is selected from one or more than two of toluene, n-pentane, isopentane, n-hexane, cyclohexane, n-heptane, and n-octane.

[0048] On the basis of the above technical solution, preferably, the components of the molybdenum catalyst used in steps (1) and (2) are a molybdenum compound, an alkyl aluminum, and a phosphate ester, the molybdenum compound is one or more than two of molybdenum pentachloride, molybdenum tetrachloride, or dichlorodimolybdenum; the alkyl aluminum is one or more than two of trimethyl aluminum, tripropyl aluminum, tributyl aluminum, diisobutyl aluminum hydride, and m-cresol aluminum; and the phosphate ester is one or more than two of triethyl phosphate, tripropyl phosphate, tributyl phosphate, triphenyl phosphate, di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester, triisopropyl phenyl phosphate, and triisooctyl phosphate.

[0049] On the basis of the above technical solution, preferably, the molar ratio of butadiene, molybdenum compound, alkyl aluminum, and phosphate ester is 5000:1:10-24:2-4.

[0050] On the basis of the above technical solution, more preferably, the formula in step (3) is: in situ-Plastic / HVBR 100 phr; carbon black 45 phr, ZnO 1.65 phr; stearic acid 1.1 phr; accelerator NS 0.55 phr; antioxidant RD 0.55 phr; and sulfur 1 phr.

[0051] On the basis of the above technical solution, more preferably, the processing technology in step (3) is: the above formula (except for sulfur) is mixed in a torque rheometer at 80°C for 15 min at 60 r / min, then the sulfur is added to the open mill for 4 times, and then the rubber is sheeted, with a sheet thickness of 2 mm.

[0052] On the basis of the above technical solution, more preferably, the vulcanization process in step (3) is: temperature 120°C-160°C, time 1-60 min, and pressure 1-10 MPa.

[0053] The second aspect of the present application provides a polystyrene in situ reinforced 1,2-polybutadiene rubber, which is prepared by the preparation method of the first aspect.

[0054] In a preferred embodiment of the present application, the mass content of 1,2 structure of the polystyrene in situ reinforced 1,2-polybutadiene rubber is 80%-85%, and / or the Mooney viscosity is 60-75.

[0055] In the present application, "and / or" means that one of the two conditions on the left and right of "and / or" can be adopted, or both conditions can exist.

[0056] The third aspect of the present application provides a use of the polystyrene in-situ reinforced 1,2-polybutadiene rubber of the second aspect in a tire and / or a tire product.

[0057] As can be known from the above description, the preparation method of the polystyrene in-situ reinforced 1,2-polybutadiene rubber (HVBR) of the present application is as follows: polystyrene is synthesized by using a molybdenum catalyst, a polymerization system is obtained after polystyrene is synthesized, the polymerization system is directly blended with butadiene monomers, and a molybdenum catalyst is added to prepare the polystyrene in-situ blended HVBR, so that the polystyrene in-situ reinforced 1,2-polybutadiene rubber (HVBR) is obtained. Because the same molybdenum catalyst is used, the post-processing is simple, the process is simple, and the problem that the residual catalyst or other impurities in the plastic reinforced by the conventional different catalytic systems will poison the molybdenum catalyst, affect the polymerization activity, and limit the industrial production is avoided. Moreover, the in-situ blended polystyrene in the HVBR has good dispersibility, the obtained product has a reduced Mooney viscosity and a high molecular weight, the processing performance is good, and the mechanical strength is improved. In addition, the polystyrene in-situ reinforced 1,2-polybutadiene rubber of the present application has improved wet skid resistance, heat generation, and rolling resistance.

[0058] The present application has the following beneficial effects:

[0059] 1) The polystyrene is prepared by using a molybdenum catalyst, and after the polymerization is completed, the impurities that poison the molybdenum catalyst in the system are few, which does not affect the polymerization of the molybdenum polybutadiene in the next step, the post-processing process is less, the process is simple, and it is beneficial to industrial amplification.

[0060] 2) In the butadiene polymerization process, the mass fraction of the polystyrene can be adjusted, the high ethylene group polybutadiene rubber with a high molecular weight and a high 1,2-structure content can be controlled, and the excellent properties of the HVBR, such as high wet skid resistance, low heat generation, and low rolling resistance, are not affected.

[0061] 3) The polystyrene is reinforced to the 1,2-polybutadiene by using the in-situ blending method, the disadvantages of poor dispersibility and poor processing performance of the polystyrene in the HVBR are avoided, the mechanical strength of the obtained product is obviously improved, the Mooney viscosity is reduced, the processing performance is good, and the wet skid resistance, heat generation, and rolling resistance are improved.

[0062] In summary, on one hand, the preparation method of the present application has high polymerization activity and monomer conversion rate, and is suitable for industrial production; on the other hand, the polystyrene in-situ reinforced 1,2-polybutadiene rubber of the present application has obvious improvement in mechanical strength, and not only that, the polystyrene in-situ reinforced 1,2-polybutadiene rubber has lower Mooney viscosity and better processing performance, and more unexpectedly, has higher molecular weight under the condition of lower Mooney viscosity, and not only that, the polystyrene in-situ reinforced 1,2-polybutadiene rubber has slightly improved wet skid resistance, heat generation and rolling resistance performance. In view of the comprehensive performance of the polystyrene in-situ reinforced 1,2-polybutadiene rubber of the present application, the rubber is suitable for tires and products, further broadens the application range of 1,2-polybutadiene rubber, and has extremely high application value. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 The infrared spectra of Comparative Example 1 and Examples 1-2 are shown in the following figure:

[0064] The infrared spectra of Comparative Example 1 and Examples 1-2 are shown in the following figure: Figure 1 As can be seen, in the infrared spectra of Comparative Example 1 and Examples 1-2, the absorption peak at 698 cm-1 is the polystyrene absorption peak, the absorption peak at 908 cm-1 is the absorption peak of 1,2-polybutadiene structure, and the absorption peak at 968 cm-1 is the absorption peak of 1,4-polybutadiene structure. -1 -1 -1 The absorption peak at 968 cm-1 is the absorption peak of 1,4-polybutadiene structure. It is shown that the polybutadiene chain in the polymerization product is mainly 1,2-polybutadiene, and the product is a high-vinyl polymerization product.

[0065] Figure 2 The scanning electron micrographs of Comparative Examples 1-3 and Example 1 are shown in the following figure. The scale in the figure is 10 μm, and the white circles are the etched polystyrene;

[0066] Figure 3 The dynamic mechanical property graphs of Comparative Examples 1-3 and Example 1 are shown in the following figure. DETAILED DESCRIPTION

[0067] It is necessary to point out here that the following examples are only used to further illustrate the present application, and cannot be understood as limiting the protection scope of the present application, and some non-essential improvements and adjustments of the present application made by those skilled in the art according to the content of the present application still fall within the protection scope of the present application.

[0068] The specific embodiments of the present application are further described below in combination with examples and drawings.

[0069] ​​The experimental methods described in the following examples are conventional methods, unless otherwise specified; the specific techniques or conditions not specified in the examples are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions; the reagents and materials used are analytical reagents, unless otherwise specified, which can be obtained commercially.

[0070] The unit of amount phr is the number of parts added per 100 parts of rubber by mass. In the following examples, as an example, M in the styrene toluene solution with a concentration of 1.5M refers to mol / L.

[0071] The test methods used in the examples and comparative examples are described as follows:

[0072] 1. Infrared spectroscopy (FTIR) test was determined on a VERTEX 70 (Bruker, Germany) infrared spectrometer in the total reflection mode.

[0073] 2. Scanning electron microscopy (SEM) test was analyzed on a JMS-6700F (Japan JEOL) scanning microscope equipped with an energy dispersive X-ray (EDX ISIS 300, Oxford, UK) microanalysis system. Before the SEM test, the sample was frozen in liquid nitrogen and then extracted with toluene in a Soxhlet extractor for 24 hours.

[0074] 3. Tensile and tear tests were performed on a GT-AT-7000M (Taiwan Gotech, China) electronic tensile testing machine at a speed of 500 mm / min.

[0075] 4. Dynamic mechanical properties were measured by DMA Q800 (TA, United States) in temperature sweep mode at -60°C to 80°C at a rate of 3°C / min, with a vibration amplitude of 10 μm and a frequency of 1 Hz.

[0076] 5. The detection method of monomer conversion rate is weighing method;

[0077] 6. The detection method of number average molecular weight is GPC; the detection method of Mw / Mn is mass spectrometry;

[0078] 7. The detection method of Mooney viscosity is GB / T 1232.1-2016;

[0079] 8. The detection method of 1,2-butadiene structure content is infrared spectroscopy;

[0080] 9. The detection method of damping performance: DMA Q800 (TA, United States) in temperature sweep mode at -60°C to 80°C at a rate of 3°C / min, with a vibration amplitude of 10 μm and a frequency of 1 Hz.

[0081] Preparation Example 1 (Preparation of molybdenum-based polystyrene)

[0082] A styrene toluene solution with a concentration of 1.5 M was added to the reactor and heated to 70°C, then the molybdenum-based catalyst was injected into the reactor, the molar ratio of styrene, molybdenum pentachloride, m-cresol aluminum and triethyl phosphate was 5000:1:10:2, the polymerization reaction was 9h, to obtain molybdenum-based polystyrene (PS), and cooled for standby.

[0083] Preparation Example 2 (Preparation of molybdenum-based polystyrene)

[0084] A styrene toluene solution with a concentration of 1.0 M was added to the reactor and heated to 80°C, then the molybdenum-based catalyst was injected into the reactor, the molar ratio of styrene, molybdenum pentachloride, m-cresol aluminum and triethyl phosphate was 4000:1:12:1.5, the polymerization reaction was 8h, to obtain molybdenum-based polystyrene (PS), and cooled for standby.

[0085] Preparation Example 3 (Preparation of molybdenum-based polystyrene)

[0086] A styrene toluene solution with a concentration of 1.2 M was added to the reactor and heated to 75°C, then the molybdenum-based catalyst was injected into the reactor, the molar ratio of styrene, molybdenum pentachloride, m-cresol aluminum and triethyl phosphate was 6000:1:15:1.2, the polymerization reaction was 8.5h, to obtain molybdenum-based polystyrene (PS), and cooled for standby.

[0087] Example 1

[0088] A certain amount of polystyrene toluene solution obtained from Preparation Example 1 was added to a butadiene n-hexane solution with a concentration of 2.6 M under a nitrogen atmosphere and heated to 60°C, wherein the mass of polystyrene was 5% of the mass of butadiene. Then, the molybdenum-based catalyst was injected into the reactor, the molar ratio of butadiene, molybdenum pentachloride, m-cresol aluminum and tri-n-butyl phosphate was 5000:1:10:2. The reaction was 6h, ethanol was added to terminate polymerization, the obtained rubber-plastic composite material was poured into boiling water to obtain a precipitate, and vacuum dried at 80°C to constant weight to obtain in-situ blended polystyrene / 1,2-polybutadiene rubber (HVBR / PS5).

[0089] The obtained 100 phr in situ blended polystyrene / 1,2-polybutadiene rubber was in situ blended in an internal mixer with 45 phr carbon black, 1.65 phr ZnO, 1.1 phr stearic acid, 0.55 phr accelerator NS, 0.55 phr antioxidant RD, and then, after mixing for 15 min at 80°C and 60 r / min, 1 phr sulfur was added to the mixer and passed through four times, and then the rubber was discharged and the thickness of the sheet was 2 mm. The rubber was cured at 150°C for 30 min under a pressure of 5 MPa to obtain vulcanized polystyrene / 1,2-polybutadiene rubber (in situ-HVBR / PS5).

[0090] Example 2

[0091] The same method as in Example 1 was used, except that the solvent for the butadiene solution was selected from n-pentane, the mass fraction of polystyrene in butadiene was 8%, the molybdenum compound was molybdenum tetrachloride, the alkyl aluminum and the phosphate were tripropyl aluminum and di(2-ethylhexyl) phosphate, respectively, and the molar ratio of butadiene, molybdenum compound, alkyl aluminum and phosphate was 5000:1:14:2. The same mixing formula and curing process as in Example 1 were used to prepare an HVBR / PS rubber-plastic composite material (HVBR / PS8) with a mass fraction of polystyrene of 8%, which was named in situ-HVBR / PS8.

[0092] Example 3

[0093] The same method as in Example 1 was used, except that the solvent for the butadiene solution was selected from n-pentane, the mass fraction of polystyrene in butadiene was 10%, the molybdenum compound was molybdenum tetrachloride, the alkyl aluminum and the phosphate were tripropyl aluminum and di(2-ethylhexyl) phosphate, respectively, and the molar ratio of butadiene, molybdenum compound, alkyl aluminum and phosphate was 5000:1:14:2. The same mixing formula and curing process as in Example 1 were used to prepare an HVBR / PS rubber-plastic composite material (HVBR / PS10) with a mass fraction of polystyrene of 10%, which was named in situ-HVBR / PS10.

[0094] Example 4

[0095] The polystyrene in situ reinforced 1,2-polybutadiene rubber (after vulcanization) was prepared according to the method of Example 2, except that the polystyrene toluene solution in Preparation Example 2 was used instead of the polystyrene toluene solution in Preparation Example 1.

[0096] Example 5

[0097] The polystyrene in situ reinforced 1,2-polybutadiene rubber (after vulcanization) was prepared according to the method of Example 2, except that the polystyrene toluene solution in Preparation Example 3 was used instead of the polystyrene toluene solution in Preparation Example 1.

[0098] Example 6

[0099] The polystyrene in-situ reinforced 1,2-polybutadiene rubber (after vulcanization) was prepared according to the method of Example 3, except that the polystyrene toluene solution in Preparation Example 3 was used instead of the polystyrene toluene solution in Preparation Example 1.

[0100] Example 7

[0101] The polystyrene in-situ reinforced 1,2-polybutadiene rubber (after vulcanization) was prepared according to the method of Example 3, except that the amount of the mixture of polystyrene was such that the mass ratio of polystyrene to butadiene was 18:100.

[0102] Example 8

[0103] The polystyrene in-situ reinforced 1,2-polybutadiene rubber (after vulcanization) was prepared according to the method of Example 3, except that the amount of the mixture of polystyrene was such that the mass ratio of polystyrene to butadiene was 20:100, and the molar ratio of butadiene, molybdenum compound, alkyl aluminum and phosphate was 7000:1:8:3.

[0104] Example 9

[0105] The polystyrene in-situ reinforced 1,2-polybutadiene rubber (after vulcanization) was prepared according to the method of Example 3, except that the amount of the mixture of polystyrene was such that the mass ratio of polystyrene to butadiene was 18:100, and the molar ratio of butadiene, molybdenum compound, alkyl aluminum and phosphate was 7000:1:8:1.5.

[0106] Comparative Example 1 (HVBR without styrene)

[0107] A pure HVBR 01 was prepared by polymerizing butadiene using the same polymerization method as in Example 1 but without adding polystyrene, and a HVBR 02 vulcanizate without polystyrene was prepared by using the same mixing formulation and vulcanization process as in Example 1 for the obtained pure HVBR.

[0108] Comparative Example 2 (HVBR / PS rubber-plastic composite by physical blending)

[0109] A pure HVBR was prepared by polymerizing butadiene using the same polymerization method as in Example 1 but without adding polystyrene, and a physical blend of 100 phr of the obtained polymer and 5% polystyrene was prepared to obtain a physical blend of 100 phr of the obtained polymer and 5% polystyrene, and a HVBR / PS rubber-plastic composite with a polystyrene mass fraction of 5% was prepared by using the same mixing formulation and vulcanization process as in Example 1 on a two-roll open mill, and was named Ph-HVBR / PS5.

[0110] Comparative Example 3 (Solution coagulation method HVBR / PS rubber- plastic composite)

[0111] The same polymerization method as in Example 1 was used to polymerize butadiene, but no polystyrene was added to prepare pure HVBR. After the HVBR was dissolved, 5% by mass of the polystyrene obtained in Preparation Example 1 was added, the product was poured into boiling water to precipitate, and dried to constant weight in a vacuum drying oven at 80°C to obtain solution coagulation method HVBR / PS5. The same mixing formulation and vulcanization process as in Example 1 were used to obtain a solution coagulation HVBR / PS rubber-plastic composite with a polystyrene mass fraction of 5%, which was named So-HVBR / PS5.

[0112] Polymerization activity and performance test

[0113] As can be seen from Table 1:

[0114] Monomer conversion rate is an important indicator for evaluating the catalytic effect of the catalytic system. High conversion rate is conducive to improving monomer utilization and reducing catalyst usage and raw material consumption. As can be seen from Table 1, the addition of molybdenum-based polystyrene does not affect the polymerization activity. As can be seen by comparing with Comparative Example 1, when the amount of molybdenum-based polystyrene added is 10%, the monomer conversion rate only decreases by 1%.

[0115] As can be seen from Comparative Example 1, the catalyst activity in the molybdenum-based HVBR is high, chain transfer is not easy, the molecular weight is large, the Mooney viscosity is large, and the processing performance is poor. After the addition of polystyrene, although the number average molecular weight of HVBR is significantly reduced, it is still above 300,000, and the molecular weight distribution is widened. Therefore, the addition of polystyrene can reduce the Mooney viscosity and improve the processing performance without affecting the performance.

[0116] Different conditions of conventional preparation methods can affect the 1,2-structure content. Low 1,2-structure content can affect the performance of the product, and high 1,2-structure content can improve the wet skid resistance and rolling resistance performance of the product. After the addition of polystyrene using the preparation method of the present application, the 1,2-structure content of HVBR is above 80%, which also indicates that this in-situ blending method does not affect the configuration of the active center of the molybdenum-based HVBR. The product obtained still belongs to high-vinyl polybutadiene.

[0117] Table 1 Effect of polystyrene on the activity and structure of polybutadiene

[0118]

[0119]

[0120] After the sample was vulcanized, the brittle sample strip was extracted with toluene using a Soxhlet extractor for 24 hours to remove styrene from the system. Then, SEM scanning was performed to analyze the dispersion of styrene in HVBR by different dispersion methods. Figure 2 In the figure, the white circles mark the holes left after the styrene is etched away. The largest hole size (10 μm) is found in Comparative Example 2 (Ph-HVBR / PS5), indicating that the styrene dispersion in HVBR is relatively poor in the physical blending method. The hole size is also relatively small in Comparative Example 3 (So-HVBR / PS5) and Example 1 (Insitu-HVBR / PS5). Moreover, compared with So-HVBR / PS5, the surface of the material in Example 1 is smoother and the styrene dispersion is better.

[0121] Table 2 Mechanical properties of samples prepared under different conditions

[0122] PS (wt% Bd) Tensile strength (MPa) Tear strength (MPa) Comparative Example 1 0 10 28 Comparative Example 2 5 12 30 Comparative Example 3 5 14 31 Example 1 5 16 36 Example 2 8 18 34 Example 3 10 17 32 Example 4 8 18 33 Example 5 8 18.5 33 Example 6 10 17.5 34 Example 7 18 16 33 Example 8 20 15 32 Example 9 20 15.5 32

[0123] The effects of different blending methods on the tensile strength and tear strength of the materials (after vulcanization) are shown in Table 2. Compared with Comparative Examples 1-3, the tensile strength and tear strength of the rubber materials obtained by the in-situ blending method of this invention are significantly improved. For example, the tensile strength of Example 1 obtained by the in-situ blending method is increased by 1.5 times, and the tear strength is increased by 1.2 times. The HVBR without styrene reinforcement in Comparative Example 1 has the worst mechanical properties, while the mechanical properties of the HVBR with added styrene in Comparative Examples 2 and 3 are improved compared with the comparative examples, but are significantly lower than those of the products of the embodiments of this invention.

[0124] Table 3 Damping performance of Comparative Examples 1-3 and Example 1

[0125]

[0126] Depend on Figure 3 Table 2 shows that the effective damping temperature range (tanδ>0.3) of the mechanically blended comparative example 2 (Ph-HVBR / PS5) is 32.73℃, which is lower than that of the non-styrene-added comparative example 1 (HVBR) at 35.62℃. In Example 1, the damping temperature range of 1 (Insitu-HVBR / PS5) is the largest decrease at 32.37℃. This indicates that the mechanical blending method results in the least uniform dispersion of PS in HVBR, while the in-situ blending method results in a more uniform dispersion of PS in HVBR.

[0127] In Example 1 of the in-situ blending method, the In situ-HVBR / PS5 had the highest tanδ value at 0°C, indicating improved wet skid resistance, while the lowest tanδ values ​​were at 60°C and 80°C, indicating reduced rolling resistance and heat generation.

[0128] In conclusion, the present application can reduce the Mooney viscosity of HVBR polymer, improve the processing performance, the Mooney viscosity of the obtained polymer is reduced to 60-75, so that the processing performance is better, the molecular weight can still be maintained at about 300,000, the tensile strength is above 16 MPa, the tear strength is above 32 MPa, and the mechanical property is obviously improved. Moreover, the content of 1,2-structure in the polymer is above 80 wt%, and the product is a high ethylene group polymerization product.

[0129] The rubber product is used in a tire, and the tire has good wet skid resistance, so that the tire can reduce the probability of slipping on a wet ground. The system has good heat generation performance, so that the tire has low heat generation during movement friction, and reduces the temperature of the tire. The improved rolling resistance performance indicates that the tire has small resistance and low energy consumption during rolling. According to the above detection, the polymer product is applied to a tire product of an automobile or an airplane, which has good wet skid resistance on a wet road, can reduce the temperature of the tire during use, improve the service life, and has small rolling resistance of the tire, so that the energy consumption can be reduced.

[0130] Of course, the above content is only a preferred embodiment of the present application, and cannot be considered as limiting the scope of the embodiments of the present application. The present application is also not limited to the above examples, and equivalent changes and improvements made by those skilled in the art within the essential scope of the present application should be attributed to the patent coverage range of the present application.

[0131] It should be noted that the above-described embodiments are only used to explain the present application and do not constitute any limitation on the present application. The present application is described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. The present application can be modified within the scope of the claims of the present application, and the present application can be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and embodiments, it does not mean that the present application is limited to the specific examples disclosed therein, on the contrary, the present application can be extended to all other methods and applications having the same function.

[0132] All publications, patent applications, patents and other references mentioned in this specification are hereby incorporated by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the definition in this specification applies.

[0133] When the specification derives a material, substance, method, step, device or component, etc. with the word head "known to those skilled in the art", "prior art" or similar words, the object derived by the word head covers those commonly used in the art at the time of the present application, but also includes those which are not yet commonly used but will be recognized as suitable for similar purposes in the art.

[0134] The endpoints of the ranges and any values disclosed in the present application document are not limited to the precise values recited as implicitly contained therein. The ranges and values are approximations that are already sufficiently accurate for the purposes to be served by the present application. When the application recites a range of values, it is contemplated that any other range or value within the scope of the range is also contemplated. Any value within the range is also contemplated. The upper and lower limits of these intervening ranges can be independently combined with any other range or value, and this applies to every range and value contained in the above description. All instances of any value or range of values are intended to encompass individual values and ranges of values therein. All instances of the term "comprising" or "containing" shall be understood to encompass the presence of the stated feature, integer, step, or component as well as those additional features, integers, steps, or components that can or can not be present. All instances of the term "including" shall be understood to encompass the presence of the stated feature, integer, step, or component as well as those additional features, integers, steps, or components that can or can not be present. All instances of the term "comprising" or "containing" shall be understood to encompass the presence of the stated feature, integer, step, or component as well as those additional features, integers, steps, or components that can or can not be present. All instances of the term "including" shall be understood to encompass the presence of the stated feature, integer, step, or component as well as those additional features, integers, steps, or components that can or can not be present. All instances of the term "including" shall be understood to encompass the presence of the stated feature, integer, step, or component as well as those additional features, integers, steps, or components that can or can not be present.

[0135] In the context of the present specification, any matter or item not mentioned, in addition to the explicitly stated content, directly applies to those known in the art without any change.

[0136] Furthermore, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or technical ideas formed thereby are considered to be part of the original disclosure or original description of the present application, and should not be considered as new content that has not been disclosed or anticipated herein, unless the combination is considered to be obviously unreasonable by those skilled in the art.

Claims

1. A method for preparing polystyrene in-situ reinforced 1,2-polybutadiene rubber, comprising: (1) performing a first polymerization reaction of a styrene solution in the presence of a first molybdenum catalyst under a protective atmosphere to obtain a mixture containing polystyrene; (2) mixing the mixture containing polystyrene obtained in step (1) with a second solvent, butadiene and a second molybdenum catalyst, and performing a second polymerization reaction under a protective atmosphere to obtain in-situ blended polystyrene / 1,2-polybutadiene rubber; the first molybdenum catalyst and the second molybdenum catalyst each comprise a molybdenum compound, an alkyl aluminum and a phosphate ester; in step (1) : the molar ratio of the styrene, the molybdenum compound, the alkyl aluminum and the phosphate ester is (100-6000) : 1 : (5-30) : (1-5) ; in step (2) : the amount of the mixture containing polystyrene is such that the mass ratio of polystyrene to butadiene is (0.5-20) : 100, based on the mass of polystyrene; and the molar ratio of the butadiene, the molybdenum compound, the alkyl aluminum and the phosphate ester is (500-8000) : 1 : (5-30) : (1-5). 2.The method according to claim 1, wherein: in step (1) : the concentration of the styrene solution is 0.96-1.92 mol / L. 3.The method according to claim 1, wherein: the conditions of the first polymerization reaction in step (1) include: a temperature of 60-90 ℃, and / or a time of 8-12 h; and / or the protective atmosphere is nitrogen and / or an inert gas; and / or the solvent used for the styrene solution is at least one of toluene, n-pentane, iso-pentane, n-hexane, cyclohexane, n-heptane and n-octane. 4.The method according to claim 1, wherein: in step (2) : the amount of the mixture containing polystyrene is such that the mass ratio of polystyrene to butadiene is (2-15) : 100, based on the mass of polystyrene; and / or the molar ratio of the butadiene, the molybdenum compound, the alkyl aluminum and the phosphate ester is (2000-6000) : 1 : (10-24) : (2-4). 5.The method according to claim 1, wherein: the amount of the second solvent is such that the concentration of butadiene in the second solvent is 1-5 mol / L; and / or the second solvent is at least one of toluene, n-pentane, iso-pentane, n-hexane, cyclohexane, n-heptane and n-octane. 6.The method according to claim 1, wherein: the conditions of the second polymerization reaction in step (2) include: a temperature of 40-80 ℃, and / or a reaction time of 4-12 h, and / or a mixing mode of stirring; and / or the protective atmosphere is nitrogen and / or an inert gas. 7.The method according to claim 1, wherein: the conditions of the second polymerization reaction in step (2) include: a mixing mode of stirring, and a stirring speed of 20-600 rpm. 8.The method according to any one of claims 1-7, wherein: the molybdenum compound is selected from at least one of molybdenum pentachloride, molybdenum tetrachloride, molybdenum dichloride dioxide; and / or, the aluminum alkyl is selected from at least one of trimethylaluminum, tripropylaluminum, tributylaluminum, diisobutylaluminum hydride, m-cresol aluminum; and / or, the phosphate ester is selected from at least one of triethyl phosphate, tripropyl phosphate, tributyl phosphate, triphenyl phosphate, di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester, triisopropyl phenyl phosphate, triisooctyl phosphate.

9. The preparation method of any one of claims 1-7, wherein: the preparation method further comprises vulcanizing the in-situ blended polystyrene / 1,2-polybutadiene rubber and the auxiliary agent mixed in step (2) to obtain the polystyrene in-situ reinforced 1,2-polybutadiene rubber.

10. The preparation method of claim 9, wherein: the auxiliary agent used for vulcanization comprises, in parts by mass, relative to 100 parts of the in-situ blended polystyrene / 1,2-polybutadiene rubber: 20-60 parts of carbon black, 1-3 parts of ZnO, 0.5-1.5 parts of stearic acid, 0.4-0.6 parts of an accelerator, 0.4-0.8 parts of an antioxidant, and 0.5-2 parts of a vulcanizing agent.

11. The preparation method of claim 9, wherein: the mixing step before vulcanization comprises: firstly mixing and compounding the in-situ blended polystyrene / 1,2-polybutadiene rubber and the auxiliary agent except the vulcanizing agent, and then adding the vulcanizing agent to open the mill; and / or, the vulcanization conditions comprise: temperature 120-160℃, and / or, time 1-60min, and / or, pressure 1-10MPa.

12. A polystyrene in-situ reinforced 1,2-polybutadiene rubber, characterized in that, The polystyrene in-situ reinforced 1,2-polybutadiene rubber is prepared by the preparation method of any one of claims 1-11.

13. The polystyrene in-situ reinforced 1,2-polybutadiene rubber of claim 12, wherein: the mass content of 1,2 structure of the polystyrene in-situ reinforced 1,2-polybutadiene rubber is 80%-85%, and / or, the Mooney viscosity is 60-75.

14. Use of the polystyrene in-situ reinforced 1,2-polybutadiene rubber of claim 12 or 13 in tires and / or tire products.

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