Liquid styrene butadiene rubber as well as preparation method and application thereof

Abstract

The invention discloses liquid styrene-butadiene rubber as well as a preparation method and application thereof. According to the invention, sodium isethionate and acrylic acid are used as raw materials to prepare the ester-containing monomer, then the ester-containing monomer is used as a third monomer to prepare the liquid styrene-butadiene rubber, a low-temperature emulsion polymerization method is adopted, and a feeding mode and a raw material ratio are improved, so that the liquid styrene-butadiene rubber is prepared. The liquid styrene-butadiene rubber with more excellent temperature resistance, wear resistance, corrosion resistance and mechanical properties is prepared by adding an emulsifier, an ester monomer, a molecular weight regulator and the like in a multi-stage manner.

Description

Technical Field

[0001] The invention relates to the field of liquid styrene butadiene rubber, and in particular to liquid styrene butadiene rubber and a preparation method and application thereof. Background Art

[0002] Liquid rubber is a viscous oligomer liquid with a relative molecular weight between 500 and 50,000 and a certain fluidity at room temperature. Its viscosity changes with the molecular weight and molecular configuration. There are many types of liquid rubber, such as liquid styrene-butadiene rubber, liquid nitrile rubber, liquid ethylene-propylene rubber, etc. Compared with solid rubber, liquid rubber has the advantages of good fluidity, easy processing, and low energy consumption, and is widely used in sealing materials, adhesives, tires and other fields.

[0003] Liquid styrene butadiene rubber is a diene copolymer liquid rubber prepared by free radical or anionic polymerization of butadiene and styrene. Free radical emulsion polymerization is currently the most commonly used preparation method due to its convenient operation, easy control of reaction temperature and fast polymerization rate. Compared with natural rubber, liquid styrene butadiene rubber has certain adhesion, heat resistance, wear resistance, mechanical properties, and good compatibility with some general-purpose rubbers. Therefore, it is widely used in adhesives, fillers, tires and other fields. However, in the face of some more extreme environments, the performance of traditional liquid styrene butadiene rubber can no longer meet the material requirements, so it is necessary to further develop liquid styrene butadiene rubber with better heat resistance, wear resistance, corrosion resistance and mechanical properties.

[0004] CN103539912A discloses a method for preparing high-performance butadiene-styrene liquid rubber, in which a terpene resin is dissolved at 80 to 110°C and grafted onto styrene butadiene latex through emulsion polymerization to obtain a terpene resin-modified liquid styrene butadiene rubber. However, the essence of this method is the modification of styrene butadiene rubber and does not involve the polymerization process of styrene butadiene rubber. It belongs to the subsequent polymerization modification of liquid styrene butadiene rubber.

[0005] CN115124663A discloses a modified styrene-butadiene rubber, comprising a styrene-butadiene rubber matrix and a modified polymer bonded to at least part of the surface of the styrene-butadiene rubber matrix, wherein the modified polymer comprises a polymer segment of a first monomer and a polymer segment of a second monomer; the first monomer is selected from acrylamide compounds, (methyl) acrylate compounds, polyolefin compounds and combinations thereof; the second monomer is selected from azo initiators containing ethylenically unsaturated groups. The modified styrene-butadiene rubber of the present application has a high grafting rate, and in the preparation process of asphalt waterproofing coiled material, the second monomer polymer segment in the modified styrene-butadiene rubber can continue to promote the cross-linking reaction between the functional groups on the polymer chain of the first monomer and other modifiers containing ethylenically unsaturated groups, thereby giving it good aging resistance. The technical solution uses styrene-butadiene rubber as a substrate, performs free radical solution polymerization on this basis, and uses ester-containing monomers and azo initiators for ternary copolymerization, and does not involve the polymerization of styrene-butadiene rubber, and belongs to the subsequent polymerization modification of styrene-butadiene rubber.

[0006] CN1468877A discloses a method for synthesizing hydroxy-terminated styrene butadiene liquid rubber, which involves using butadiene and styrene as monomers and organic peroxide as initiator to prepare a hydroxy-terminated polybutadiene-styrene liquid rubber by free radical solution polymerization.

[0007] CN111560096A once disclosed a method for preparing styrene-butadiene rubber, which involved an emulsion polymerization method, at a polymerization temperature of ≤5°C and under nitrogen protection, using styrene, butadiene, water, an emulsifier, an electrolyte, a reducing agent, an environmentally friendly molecular weight regulator and an initiator as raw materials to obtain a styrene-butadiene rubber. However, this method replaces the traditional styrene-butadiene rubber regulator and does not further improve its performance.

[0008] CN110527020A discloses a method for preparing styrene-butadiene rubber, comprising the following steps: 1) mixing butadiene, styrene, emulsifier, electrolyte, deoxidizer, activator, oxidant, regulator, and desalted water, and then performing emulsion polymerization reaction; after the reaction is completed, degassing the reaction system and adding an antioxidant to obtain latex, wherein the oxidant is peroxide pinane; 2) adding the latex to water containing a flocculant and concentrated sulfuric acid and stirring, and after the latex is coagulated, filtering and drying to obtain styrene-butadiene raw rubber, wherein the concentrated sulfuric acid is a sulfuric acid solution with a mass fraction greater than or equal to 70%; 3) mixing the styrene-butadiene raw rubber with carbon black and sulfur and performing vulcanization to obtain styrene-butadiene rubber. The preparation method can effectively shorten the polymerization time, reduce the amount of regulator, and reduce energy consumption; and different styrene-butadiene latexes and qualified styrene-butadiene rubber products can be prepared by using the preparation method.

[0009] CN108017743A discloses a modified carboxylated styrene butadiene latex and a preparation method thereof. The preparation method of the modified carboxylated styrene butadiene latex comprises the following steps: (1) in the presence of an initiator, a mixed system containing butadiene, styrene, acrylic acid, a retarder, a molecular weight regulator, water, a pH buffer, a chelating agent and an emulsifier is subjected to polymerization reaction at 55-60°C and 65-75°C in sequence; (2) the polymerization product is mixed with an oil phase containing a nitrile functional monomer, styrene and butadiene and an aqueous phase containing water, an initiator, an emulsifier and a molecular weight regulator, and the obtained mixture is subjected to polymerization reaction at 75-80°C and 85-90°C in sequence. The modified carboxylated styrene butadiene latex prepared by the method provided by the present invention not only has a small particle size, but also has excellent stability and extremely high bonding strength. The method is to carry out ternary copolymerization of carboxyl styrene butadiene latex at 55-60°C and 65-75°C, and then to carry out copolymerization grafting with a nitrile functional monomer. The method has a large number average molecular weight and is complicated. Summary of the invention

[0010] The purpose of the present invention is to provide a liquid styrene-butadiene rubber and a preparation method and application thereof.

[0011] The invention uses sodium hydroxyethyl sulfonate and acrylic acid as raw materials to prepare ester-containing monomers, which are then used as the third monomer in the preparation of liquid styrene-butadiene rubber. The invention adopts a low-temperature emulsion polymerization method, improves the feeding method and raw material ratio, and adds an emulsifier, an ester monomer, a molecular weight regulator, etc. in multiple stages to prepare a liquid styrene-butadiene rubber with better temperature resistance, wear resistance, corrosion resistance and mechanical properties.

[0012] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0013] In one aspect, the present invention provides a liquid styrene-butadiene rubber, wherein the polymerization monomers of the liquid styrene-butadiene rubber include butadiene, styrene and a sulfonic acid group-containing ester monomer;

[0014] The structural formula of the sulfonic acid ester monomer is:

[0015] According to the liquid styrene-butadiene rubber of the present invention, preferably, based on 100 parts by total weight of the butadiene, styrene and sulfonic acid ester monomer, the weight parts of each monomer are: 50-75 parts of butadiene, 20-30 parts of styrene, and 5-24 parts of sulfonic acid ester monomer.

[0016] According to the liquid styrene-butadiene rubber of the present invention, preferably, the liquid styrene-butadiene rubber is prepared by emulsion copolymerization of butadiene, styrene and sulfonic acid ester monomers.

[0017] In the liquid styrene-butadiene rubber, the content of the sulfonic acid ester monomer structure is 3wt% to 18wt%.

[0018] According to the liquid styrene butadiene rubber of the present invention, preferably, the Mooney viscosity of the liquid styrene butadiene rubber at 25° C. is 40 to 60 Pa·s, and the molecular weight Mn ranges from 3000 to 5000.

[0019] Another aspect of the present invention provides a method for preparing liquid styrene-butadiene rubber, wherein the preparation method comprises the following steps:

[0020] Based on 100 parts of the total weight of butadiene, styrene and sulfonic acid ester monomer, 160-220 parts of desalted water, 4-8 parts of emulsifier, 0.1-0.3 parts of reducing agent, 0.1-0.4 parts of diffusing agent, 0.4-0.8 parts of electrolyte, 3-6 parts of molecular weight regulator, 20-30 parts of styrene, 3-20 parts of sulfonic acid ester monomer and 0.01-0.1 parts of deoxidizer are added into a reaction container. After the addition is completed, 50-75 parts of butadiene are added in a protective gas atmosphere, and stirred for pre-emulsification, and then 0.1-0.2 parts of initiator are added for polymerization reaction;

[0021] When the three monomers of butadiene, styrene and sulfonic acid ester monomer reach a certain monomer conversion rate, emulsifier, initiator, molecular weight regulator and sulfonic acid ester monomer are added respectively. When the monomer conversion rate reaches 82-87%, 0.05-0.2 parts of terminator are added to terminate the reaction, and then degassing, condensation, washing and drying are carried out to obtain the liquid styrene-butadiene rubber.

[0022] According to the preparation method of the present invention, preferably, when the three monomers of butadiene, styrene and sulfonic acid ester monomer reach a certain monomer conversion rate, the steps of respectively adding an emulsifier, an initiator, a molecular weight regulator and a sulfonic acid ester monomer specifically include:

[0023] When the monomer conversion rate reaches 25% to 30%, add 1 to 2 parts of sulfonic acid ester monomer; when the monomer conversion rate reaches 50% to 55%, add 0.4 to 0.8 parts of emulsifier, 0.002 to 0.004 parts of initiator, and 0.5 to 0.8 parts of molecular weight regulator; when the monomer conversion rate reaches 65% to 70%, add 1 to 2 parts of sulfonic acid ester monomer.

[0024] According to the preparation method of the present invention, preferably, the emulsifier is an anionic compound surfactant or an anionic compound surfactant; wherein the anionic compound surfactant is a compound of rosin soap and fatty alkyl sulfonate, and the compound mass ratio is (4-5):1; the anionic compound surfactant is a compound of rosin soap and polyoxyethylene ether, and the compound mass ratio is (3-4):1.

[0025] According to the preparation method of the present invention, preferably, the amount of the emulsifier used is 5 to 6 parts.

[0026] According to the preparation method of the present invention, preferably, the reducing agent is selected from but not limited to at least one of sodium formaldehyde sulfoxylate, ferrous sulfate, cuprous sulfate, EDTA sodium iron salt, EDTA sodium copper salt and the like.

[0027] According to the preparation method of the present invention, preferably, the amount of the reducing agent is 0.2 to 0.3 parts.

[0028] According to the preparation method of the present invention, preferably, the dispersant is a sodium naphthalenesulfonate formaldehyde condensate, selected from but not limited to at least one of β-naphthalenesulfonate sodium formaldehyde condensate, methylnaphthalenesulfonate sodium formaldehyde condensate, benzylnaphthalenesulfonic acid formaldehyde condensate, etc.; more preferably, it is β-naphthalenesulfonate sodium formaldehyde condensate.

[0029] According to the preparation method of the present invention, preferably, the amount of the diffusing agent is 0.2 to 0.3 parts.

[0030] According to the preparation method of the present invention, preferably, the electrolyte is potassium phosphate or potassium chloride.

[0031] According to the preparation method of the present invention, preferably, the amount of the electrolyte used is 0.5 to 0.6 parts.

[0032] According to the preparation method of the present invention, preferably, the molecular weight regulator is selected from but not limited to at least one of dodecyl mercaptan, tert-dodecyl mercaptan, and 2,4-diphenyl-4-methyl-1-pentene; more preferably, the molecular weight regulator is tert-dodecyl mercaptan or 2,4-diphenyl-4-methyl-1-pentene.

[0033] According to the preparation method of the present invention, preferably, the molecular weight regulator is used in an amount of 4 to 5 parts.

[0034] According to the preparation method of the present invention, preferably, the oxygen scavenger is selected from but not limited to at least one of sodium dithionite, dimethyl ketoxime, isoascorbic acid, etc., more preferably sodium dithionite.

[0035] According to the preparation method of the present invention, preferably, the amount of the deoxidizer is 0.04 to 0.08 parts.

[0036] According to the preparation method of the present invention, preferably, the initiator is an organic hydroperoxide, including but not limited to cumene hydroperoxide, diisopropyl hydroperoxide, isopropyl tert-butyl peroxide, etc., more preferably diisopropyl hydroperoxide.

[0037] According to the preparation method of the present invention, preferably, the amount of the initiator is 0.12 to 0.18 parts.

[0038] According to the preparation method of the present invention, preferably, the polymerization reaction temperature is 5 to 25°C, more preferably 10 to 15°C.

[0039] According to the preparation method of the present invention, preferably, the terminator is selected from but not limited to at least one of hydroxylamine sulfate, diethylhydroxylamine, isopropylhydroxylamine, etc., more preferably isopropylhydroxylamine or diethylhydroxylamine.

[0040] According to the preparation method of the present invention, preferably, the amount of the terminator is 0.05 to 0.1 parts.

[0041] In the preparation method of the present invention, the degassing is preferably carried out in a degassing tower, more preferably for 4 to 5 hours, and the ester-containing styrene butadiene latex is obtained after degassing; and the liquid styrene butadiene rubber is obtained after coagulation, washing and drying. Coagulation, washing and drying are conventional techniques in the preparation of liquid styrene butadiene rubber, and the present invention does not limit this. "Protective gas" is, for example, nitrogen, argon, etc.

[0042] The preparation method of the modified high-performance liquid styrene-butadiene rubber of the present invention is simple and clear, and can be used for ternary copolymerization industrial production using existing equipment. Sulfonic acid group-containing ester monomers are introduced on the basis of traditional styrene-butadiene rubber, which contains ester groups and sulfonic acid groups at the same time. The introduction of the ester structure has the advantages of improving the heat resistance and ozone stability of the liquid styrene-butadiene rubber, improving the mechanical properties, etc., and the introduction of the sulfonic acid group can change the polarity of the liquid styrene-butadiene rubber, and further improve the wear resistance by changing the surface polarity of the styrene-butadiene rubber. At the same time, the present invention uses a method of multi-stage addition of an emulsifier, a sulfonic acid group-containing ester monomer, an initiator, and a molecular weight regulator to regulate the molecular weight of the modified high-performance liquid styrene-butadiene rubber, and improves the problem of uniform distribution of ester groups in the liquid styrene-butadiene rubber.

[0043] According to the preparation method of the present invention, preferably, the sulfonic acid ester monomer is prepared by the following reaction formula, and the specific steps include:

[0044]

[0045] Acrylic acid, sodium isethionate, a dehydrating agent and a catalyst are added to a reaction container, and the temperature is raised under a protective gas atmosphere to carry out an esterification reaction. During the reaction, generated water and the dehydrating agent are continuously evaporated, and the dehydrating agent is separated and refluxed into the reaction container to continue the reaction. When the amount of separated water no longer increases and reaches a theoretical calculated amount, the reaction is stopped, the reaction system is filtered to obtain a filter cake, and the filter cake is subjected to reduced pressure distillation to obtain the sulfonic acid group-containing ester monomer.

[0046] In the preparation process of the sulfonic acid group-containing ester monomer of the present invention, preferably, the temperature of the esterification reaction is 110-120° C., and the reaction time is 12-15 hours.

[0047] In the preparation process of the sulfonic acid ester monomer of the present invention, preferably, the molar ratio of sodium isethionate to acrylic acid is 1:(1-1.5), more preferably 1:(1.2-1.3).

[0048] In the preparation process of the sulfonic acid group-containing ester monomer of the present invention, preferably, the dehydrating agent is selected from at least one of toluene, ethylbenzene and p-toluene; more preferably, toluene or xylene.

[0049] In the preparation process of the sulfonic acid ester monomer of the present invention, preferably, the added amount of the dehydrating agent is 4 to 6 times the total mass of acrylic acid and sodium isethionate.

[0050] In the preparation process of the sulfonic acid ester monomer of the present invention, preferably, the catalyst is an organic sulfonic acid selected from but not limited to at least one of methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and 2-naphthalenesulfonic acid, more preferably benzenesulfonic acid or p-toluenesulfonic acid.

[0051] In the preparation process of the sulfonic acid ester monomer of the present invention, preferably, the amount of the catalyst used is 0.2 wt% to 0.8 wt% of the total mass of sodium hydroxyethyl sulfonate and acrylic acid, and more preferably 0.4 wt% to 0.6 wt%.

[0052] Another aspect of the present invention provides liquid styrene-butadiene rubber obtained by the above preparation method.

[0053] According to the liquid styrene butadiene rubber of the present invention, preferably, in the liquid styrene butadiene rubber, the content of the sulfonic acid ester monomer structure is 3wt% to 18wt%; the Mooney viscosity of the liquid styrene butadiene rubber at 25°C is 40 to 60 Pa·s, and the molecular weight Mn ranges from 3000 to 5000.

[0054] The preparation method of the sulfonic acid ester functional monomer designed and developed by the present invention is very suitable for industrial synthesis. Different from the current industrial production using concentrated sulfuric acid as a catalyst, the present invention uses sodium isethionate and acrylic acid as raw materials, uses organic sulfonic acid as a catalyst, and uses a dehydrating agent as a solvent. The esterification reaction efficiency is improved by removing the generated water in the esterification reaction by azeotropic removal. The sulfonic acid ester monomer can be prepared industrially by adopting this method, and the yield can reach more than 90%, realizing the self-sufficiency of the sulfonic acid ester monomer raw materials when preparing the modified high-performance liquid styrene-butadiene rubber. Subsequently, the sulfonic acid ester monomer is ternary copolymerized with butadiene and styrene by an emulsion copolymerization method, and a modified high-performance liquid styrene-butadiene rubber is prepared by a process of multi-stage addition of an emulsifier, a sulfonic acid ester monomer, a molecular weight regulator, and an initiator. The modified high-performance liquid styrene-butadiene rubber introduces a sulfonic acid ester, and the Mooney viscosity ranges from 40 to 60 Pa·s (25°C), the molecular weight Mn ranges from 3000 to 5000, and has good fluidity and easy processing performance. The introduction of ester structure improves the heat resistance of polymer, and the introduction of sulfonic acid group improves the wear resistance of polymer. The modified high-performance liquid styrene butadiene rubber can be used to replace rubber processing oil, toughening agent, improve tire tread rubber and other fields.

[0055] Another aspect of the present invention provides the use of the above liquid styrene-butadiene rubber in tires or epoxy resin toughening agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is the NMR spectrum of the sulfonic acid ester monomer prepared in Example 3.

[0057] Figure 2 This is the nuclear magnetic resonance spectrum of the modified high-performance liquid styrene-butadiene rubber prepared in Example 3.

[0058] Figure 3 This is a graph showing the effect of different addition amounts of modified high-performance liquid styrene-butadiene rubber on the wear resistance of epoxy resin cured products. DETAILED DESCRIPTION

[0059] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0060] All numerical specifications herein (e.g., temperature, time, concentration, and weight, etc., including ranges for each thereof) are generally approximate values ​​that may be appropriately varied (+) or (-) in increments of 0.1 or 1.0. All numerical specifications may be understood as being preceded by the term "about."

[0061] Example 1

[0062] This embodiment prepares a modified high-performance liquid styrene-butadiene rubber, comprising the following specific steps:

[0063] S1: At room temperature, sodium isethionate (148g, 1mol), acrylic acid (72g, 1mol) and benzenesulfonic acid (0.44g, 0.2wt%) were added to a reactor containing 880g toluene. Under nitrogen protection, the temperature was raised to 110°C for 12 hours to carry out the esterification reaction of acrylic acid and sodium isethionate. During the reaction, the water and dehydrating agent generated in the reaction were continuously evaporated. The dehydrating agent was separated and refluxed into the reactor to continue the reaction. The amount of separated water was calculated. After reaching the theoretical value, the reaction was stopped. The feed liquid was filtered to obtain a filter cake, which was added to the reactor. The dehydrating agent toluene was removed by reduced pressure distillation at 50°C and 0.2MPa, and then 175.1g of the sulfonic acid group-containing ester monomer was obtained by reduced pressure distillation at 72°C and 0.4MPa, with a yield of 86.7%.

[0064] S2: In a 10L polymerization kettle, 160 parts of desalted water, 4 parts of emulsifier (rosin soap and fatty alkyl sulfonate in a 4:1 ratio), 0.1 parts of sodium formaldehyde sulfoxylate, 0.1 parts of sodium β-naphthalenesulfonate formaldehyde condensate, 0.4 parts of potassium phosphate, 3 parts of tert-dodecyl mercaptan, 20 parts of styrene, 3 parts of sulfonic acid ester monomers and 0.01 parts of sodium dithionite were added. After the addition was completed, nitrogen was replaced three times, 75 parts of butadiene were added, and then 0.1 parts of diisopropylbenzene hydroperoxide were added at 5°C to carry out polymerization reaction.

[0065] When the monomer conversion rate of butadiene, styrene and sulfonic acid ester monomer reaches 25%, 1 part of sulfonic acid ester monomer is added; when the monomer conversion rate reaches 50%, 0.4 part of emulsifier, 0.002 part of diisopropylbenzene hydroperoxide and 0.5 part of tert-dodecyl mercaptan are added; when the monomer conversion rate reaches 65%, 1 part of sulfonic acid ester monomer is added. When the monomer conversion rate reaches 82%, 0.05 part of hydroxylamine sulfate is added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 4 hours to obtain ester-containing styrene butadiene latex, and after coagulation, washing and drying, the high-performance liquid styrene butadiene rubber containing sulfonic acid and ester groups can be obtained.

[0066] Example 2

[0067] This embodiment prepares a modified high-performance liquid styrene-butadiene rubber, comprising the following specific steps:

[0068] S1: At room temperature, sodium isethionate (148g, 1mol), acrylic acid (108g, 1.5mol) and benzenesulfonic acid (2.048g, 0.8wt%) were added to a reactor containing 1536g toluene. Under nitrogen protection, the temperature was raised to 120°C for 15 hours to carry out the esterification reaction of acrylic acid and sodium isethionate. During the reaction, the water and dehydrating agent generated in the reaction were continuously evaporated. The dehydrating agent was separated and refluxed into the reactor to continue the reaction. The amount of separated water was calculated. After reaching the theoretical value, the reaction was stopped. The feed liquid was filtered to obtain a filter cake. The filter cake was added to the reactor, and the dehydrating agent toluene was removed by reduced pressure distillation at 50°C and 0.2MPa. Then, 178.4g of the sulfonic acid group-containing ester monomer was obtained by reduced pressure distillation at 72°C and 0.4MPa, with a yield of 88.3%.

[0069] S2: In a 10L polymerization kettle, 220 parts of desalted water, 8 parts of emulsifier (rosin soap and fatty alkyl sulfonate with a compound ratio of 5:1 emulsifier), 0.3 parts of ferrous sulfate, 0.4 parts of sodium methylnaphthalene sulfonate formaldehyde condensate, 0.8 parts of potassium chloride, 6 parts of dodecyl mercaptan, 21 parts of styrene, 5 parts of sulfonic acid ester monomer and 0.1 parts of sodium dithionite were added. After the addition was completed, nitrogen was replaced three times, 70 parts of butadiene were added, and then 0.1 parts of cumene hydroperoxide were added at 25°C to carry out polymerization reaction.

[0070] When the monomer conversion rate of butadiene, styrene and sulfonic acid ester monomer reaches 30%, 2 parts of sulfonic acid ester monomer are added; when the monomer conversion rate reaches 55%, 0.8 parts of emulsifier, 0.004 parts of cumene hydroperoxide and 0.8 parts of dodecyl mercaptan are added; when the monomer conversion rate reaches 70%, 2 parts of sulfonic acid ester monomer are added. When the monomer conversion rate reaches 87%, 0.05 parts of diethylhydroxylamine are added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 5 hours to obtain ester-containing styrene butadiene latex, and after coagulation, washing and drying, the high-performance liquid styrene butadiene rubber containing sulfonic acid and ester groups can be obtained.

[0071] Example 3

[0072] This embodiment prepares a modified high-performance liquid styrene-butadiene rubber, comprising the following specific steps:

[0073] S1: At room temperature, sodium isethionate (148 g, 1 mol), acrylic acid (86.4 g, 1.2 mol) and benzenesulfonic acid (1.172 g, 0.5 wt%) were added to a reactor containing 950 g toluene. Under nitrogen protection, the temperature was raised to 120°C for 15 hours to carry out the esterification reaction of acrylic acid and sodium isethionate. During the reaction, the water and dehydrating agent generated in the reaction were continuously evaporated. The dehydrating agent was separated and refluxed into the reactor to continue the reaction. The amount of separated water was calculated. When the theoretical value was reached, the reaction was stopped. The feed liquid was filtered to obtain a filter cake. The filter cake was added to the reactor, and the dehydrating agent toluene was removed by reduced pressure distillation at 50°C and 0.2 MPa. Then, 186.6 g of the sulfonic acid group-containing ester monomer was obtained by reduced pressure distillation at 72°C and 0.4 MPa, with a yield of 92.4%.

[0074] S2: In a 10L polymerization kettle, 190 parts of desalted water, 5 parts of emulsifier (rosin soap and fatty alkyl sulfonate in a 4:1 ratio), 0.2 parts of EDTA sodium iron salt, 0.3 parts of benzylnaphthalenesulfonic acid formaldehyde condensate, 0.5 parts of potassium phosphate, 4 parts of 2,4-diphenyl-4-methyl-1-pentene, 26 parts of styrene, 12 parts of sulfonic acid ester monomer and 0.05 parts of isoascorbic acid were added. After the addition was completed, nitrogen was replaced three times, 60 parts of butadiene were added, and then 0.15 parts of isopropyl tert-butyl peroxide were added at 15°C for polymerization.

[0075] When the monomer conversion rate of butadiene, styrene and sulfonic acid ester monomer reaches 25%, 1 part of sulfonic acid ester monomer is added; when the monomer conversion rate reaches 50%, 0.5 part of emulsifier, 0.003 part of isopropyl tert-butyl peroxide and 0.6 part of 2,4-diphenyl-4-methyl-1-pentene are added; when the monomer conversion rate reaches 65%, 1 part of sulfonic acid ester monomer is added. When the monomer conversion rate reaches 85%, 0.05 part of isopropyl hydroxylamine is added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 5 hours to obtain ester-containing styrene butadiene latex. After coagulation, washing and drying, the high-performance liquid styrene butadiene rubber containing sulfonic acid and ester groups can be obtained.

[0076] Example 4

[0077] This embodiment prepares a modified high-performance liquid styrene-butadiene rubber, comprising the following specific steps:

[0078] S1: At room temperature, sodium isethionate (148g, 1mol), acrylic acid (93.6g, 1.3mol) and benzenesulfonic acid (0.9664g, 0.4wt%) were added to a reactor containing 1208g toluene. Under nitrogen protection, the temperature was raised to 115°C for 14 hours to carry out the esterification reaction of acrylic acid and sodium isethionate. During the reaction, the water and dehydrating agent generated in the reaction were continuously evaporated. The dehydrating agent was separated and refluxed into the reactor to continue the reaction. The amount of separated water was calculated. After reaching the theoretical value, the reaction was stopped. The feed liquid was filtered to obtain a filter cake, which was added to the reactor. The dehydrating agent toluene was removed by reduced pressure distillation at 50°C and 0.2MPa, and then 181.3g of the sulfonic acid ester monomer was obtained by reduced pressure distillation at 72°C and 0.4MPa, with a yield of 89.8%.

[0079] S2: In a 10L polymerization kettle, 200 parts of desalted water, 6 parts of emulsifier (rosin soap and polyoxyethylene ether compound ratio 3:1 emulsifier), 0.1 parts of EDTA copper sodium salt, 0.2 parts of sodium β-naphthalenesulfonate formaldehyde condensate, 0.4 parts of potassium chloride, 5 parts of 2,4-diphenyl-4-methyl-1-pentene, 23 parts of styrene, 15 parts of sulfonic acid ester monomer and 0.06 parts of dimethyl ketone oxime were added. After the addition was completed, nitrogen was replaced three times, 60 parts of butadiene were added, and then 0.12 parts of diisopropylbenzene hydroperoxide were added at 10°C for polymerization reaction.

[0080] When the monomer conversion rate of butadiene, styrene and sulfonic acid ester monomer reaches 25%, 1 part of sulfonic acid ester monomer is added; when the monomer conversion rate reaches 55%, 0.8 part of emulsifier, 0.002 part of diisopropylbenzene hydroperoxide and 0.5 part of 2,4-diphenyl-4-methyl-1-pentene are added; when the monomer conversion rate reaches 65%, 1 part of sulfonic acid ester monomer is added. When the monomer conversion rate reaches 83%, 0.05 part of hydroxylamine sulfate is added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 4 hours to obtain ester-containing styrene butadiene latex. After coagulation, washing and drying, the high-performance liquid styrene butadiene rubber containing sulfonic acid and ester groups can be obtained.

[0081] Example 5

[0082] This embodiment prepares a modified high-performance liquid styrene-butadiene rubber, comprising the following specific steps:

[0083] S1: At room temperature, sodium isethionate (148 g, 1 mol), acrylic acid (86.4 g, 1.2 mol) and benzenesulfonic acid (1.4064 g, 0.6 wt%) were added to a reactor containing 1200 g toluene. Under nitrogen protection, the temperature was raised to 110°C for 13 hours to carry out the esterification reaction of acrylic acid and sodium isethionate. During the reaction, water and dehydrating agent generated in the reaction were continuously evaporated. The dehydrating agent was separated and refluxed into the reactor to continue the reaction. The amount of separated water was calculated. After reaching the theoretical value, the reaction was stopped. The feed liquid was filtered to obtain a filter cake, which was added to the reactor. The dehydrating agent toluene was removed by reduced pressure distillation at 50°C and 0.2 MPa, and then 185.2 g of the sulfonic acid group-containing ester monomer was obtained by reduced pressure distillation at 72°C and 0.4 MPa, with a yield of 91.7%.

[0084] S2: In a 10L polymerization kettle, 180 parts of desalted water, 7 parts of emulsifier (rosin soap and polyoxyethylene ether compound ratio 4:1 emulsifier), 0.3 parts of sodium formaldehyde sulfoxylate, 0.3 parts of benzylnaphthalenesulfonic acid formaldehyde condensate, 0.6 parts of potassium phosphate, 4 parts of tert-dodecyl mercaptan, 25 parts of styrene, 8 parts of sulfonic acid ester monomer and 0.04 parts of isoascorbic acid were added. After the addition was completed, nitrogen was replaced three times, 63 parts of butadiene were added, and then 0.18 parts of diisopropylbenzene hydroperoxide were added at 10°C for polymerization reaction.

[0085] When the monomer conversion rate of butadiene, styrene and sulfonic acid ester monomer reaches 30%, 2 parts of sulfonic acid ester monomer are added; when the monomer conversion rate reaches 55%, 0.4 parts of emulsifier, 0.002 parts of diisopropylbenzene hydroperoxide and 0.6 parts of tert-dodecyl mercaptan are added; when the monomer conversion rate reaches 70%, 2 parts of sulfonic acid ester monomer are added. When the monomer conversion rate reaches 86%, 0.15 parts of isopropylhydroxylamine are added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 5 hours to obtain ester-containing styrene butadiene latex, and after coagulation, washing and drying, the high-performance liquid styrene butadiene rubber containing sulfonic acid and ester groups can be obtained.

[0086] Example 6

[0087] This embodiment provides a preparation method and application of a modified high-performance liquid styrene-butadiene rubber, which is prepared by a preparation method comprising the following specific steps:

[0088] S1: At room temperature, sodium isethionate (148g, 1mol), acrylic acid (108g, 1.5mol) and benzenesulfonic acid (0.512g, 0.2wt%) were added to a reactor containing 1350g toluene. Under nitrogen protection, the temperature was raised to 115°C for 12 hours to carry out the esterification reaction of acrylic acid and sodium isethionate. During the reaction, the water and dehydrating agent generated in the reaction were continuously evaporated. The dehydrating agent was separated and refluxed into the reactor to continue the reaction. The amount of separated water was calculated. After reaching the theoretical value, the reaction was stopped. The feed liquid was filtered to obtain a filter cake. The filter cake was added to the reactor, and the dehydrating agent toluene was removed by reduced pressure distillation at 50°C and 0.2MPa. Then, 172.1g of the sulfonic acid group-containing ester monomer was obtained by reduced pressure distillation at 72°C and 0.4MPa, with a yield of 85.2%.

[0089] S2: In a 10L polymerization kettle, 210 parts of desalted water, 5 parts of emulsifier (rosin soap and fatty alkyl sulfonate with a compound ratio of 4:1 emulsifier), 0.2 parts of ferrous sulfate, 0.3 parts of sodium β-naphthalenesulfonate formaldehyde condensate, 0.5 parts of potassium phosphate, 5 parts of tert-dodecyl mercaptan, 29 parts of styrene, 18 parts of sulfonic acid ester monomer and 0.08 parts of dimethyl ketoxime were added. After the addition was completed, nitrogen was replaced three times, 50 parts of butadiene were added, and then 0.16 parts of diisopropylbenzene hydroperoxide were added at 10°C to carry out polymerization reaction.

[0090] When the monomer conversion rate of butadiene, styrene and sulfonic acid ester monomer reaches 25%, 2 parts of sulfonic acid ester monomer are added; when the monomer conversion rate reaches 50%, 0.5 parts of emulsifier, 0.004 parts of diisopropylbenzene hydroperoxide and 0.5 parts of tert-dodecyl mercaptan are added; when the monomer conversion rate reaches 65%, 1 part of sulfonic acid ester monomer is added. When the monomer conversion rate reaches 85%, 0.15 parts of diethylhydroxylamine are added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 4 hours to obtain ester-containing styrene butadiene latex, and after coagulation, washing and drying, the high-performance liquid styrene butadiene rubber containing sulfonic acid and ester groups can be obtained.

[0091] Structural characterization and performance testing:

[0092] In order to characterize the structural characteristics of the obtained high-performance liquid styrene-butadiene rubber, the sulfonic acid ester monomer and the liquid styrene-butadiene rubber obtained in Example 3 were subjected to nuclear magnetic resonance measurement. The test results are as follows: Figure 1 and Figure 2 shown.

[0093] from Figure 1 It can be seen from the nuclear magnetic hydrogen spectrum of the sulfonic acid ester monomer: 1HNMR (400MHz, CDCl3), δ6.48~6.41 (m, CH2=CH-, 1H), 6.22~6.12 (m, CH2=CH-, 1H), 5.83~5.62 (m, CH2=CH-, 1H), 4.59~4.52 (t, CH2=CH-COO-CH2-, 2H), 2.78~2.71 (m, CH2=CH-COO-CH2-CH2-SO3Na, 2H). All of them correspond to the characteristic peaks of sulfonic acid ester monomers, indicating that sulfonic acid ester monomers have been successfully prepared. The remaining embodiments are not listed here one by one. The yields of sulfonic acid ester monomers in embodiments 1 to 6 are all maintained at about 85%. At the same time, different from laboratory synthesis, this method can be used for industrial synthesis and production amplification.

[0094] from Figure 2 It can be seen from the NMR hydrogen spectrum of liquid styrene butadiene rubber: 1 HNMR (400 MHz, CDCl3), the peak at δ4.66 (a) is -COO-CH2-CH2-SO3Na next to the ester group, the peak at δ2.74 (b) is -CH2-SO3Na next to the sulfonic acid group, the peak at δ2.56 (c) is C6H5-CH- next to the benzene ring, and the peak at δ2.26 (d) is -CH-COO-CH2-CH2-SO3Na next to the ester group. This proves that the high-performance liquid styrene-butadiene rubber modified with sulfonic acid ester monomer was successfully prepared.

[0095] In order to characterize the basic properties of the obtained liquid styrene-butadiene rubber, the liquid styrene-butadiene rubber containing sulfonic acid groups and ester groups prepared in Examples 1 to 6 was subjected to corresponding performance tests. Among them, the styrene content was measured according to the refractive index method in GB / T 8658-1998; the content of sulfonic acid ester monomers was obtained by nuclear magnetic area integration; the molecular weight was measured according to the gel permeation chromatography method in SH / T1759-2007; the Mooney viscosity was measured according to GB / T 1232.1-2016 using a Mooney viscometer (GT-7082S2). The test results are shown in Table 1.

[0096] Table 1

[0097] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Bound styrene content, wt% 19.3 20.4 24.7 21.2 23.1 28.3 Sulfonic acid ester content, wt% 3.4 8.1 12.7 14.6 10.3 17.8 Molecular weight, Mn 4584 3169 3956 3768 4327 3862 Mooney viscosity, Pa·s@25℃ 56.1 44.3 49.8 47.2 54.7 50.2 Glass transition temperature, °C -46 -49 -56 -58 -51 -54

[0098] As can be seen from Table 1, the modified high-performance liquid styrene-butadiene rubbers prepared in Examples 1 to 6 all have sulfonic acid esters introduced therein, and have Mooney viscosities ranging from 40 to 60 Pa·s and molecular weights Mn ranging from 3000 to 5000, and have good fluidity and easy processing properties.

[0099] In order to verify the effect of multi-stage addition of emulsifier, sulfonic acid ester monomer, initiator and molecular weight regulator on the performance of modified high-performance liquid styrene-butadiene rubber during the preparation process, the relevant data were compared with the comparative examples under different conditions with reference to Example 3. The comparative example preparation method is as follows:

[0100] Comparative Example 1

[0101] Compared with Example 3, Comparative Example 1 adopts a one-time monomer addition method without any additional addition, and the specific S2 is as follows:

[0102] In a 10L polymerization kettle, 190 parts of desalted water, 5 parts of emulsifier (rosin soap and fatty alkyl sulfonate compound ratio 4:1 emulsifier), 0.2 parts of EDTA sodium iron salt, 0.3 parts of benzylnaphthalenesulfonic acid formaldehyde condensate, 0.5 parts of potassium phosphate, 4 parts of 2,4-diphenyl-4-methyl-1-pentene, 26 parts of styrene, 14 parts of sulfonic acid ester monomer and 0.05 parts of isoascorbic acid were added. After the addition was completed, nitrogen was replaced three times, 60 parts of butadiene were added, and then 0.15 parts of isopropyl tert-butyl peroxide were added at 15°C for polymerization.

[0103] When the monomer conversion rate reaches 50%, 0.5 parts of emulsifier, 0.003 parts of isopropyl tert-butyl peroxide and 0.6 parts of 2,4-diphenyl-4-methyl-1-pentene are added; when the monomer conversion rate reaches 85%, 0.05 parts of isopropylhydroxylamine are added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 5 hours to obtain ester-containing styrene butadiene latex, and liquid styrene butadiene rubber can be obtained after coagulation, washing and drying.

[0104] Comparative Example 2

[0105] Compared with Example 3, Comparative Example 2 adopts a one-time addition of initiator, and other conditions remain unchanged. Specific S2 is as follows:

[0106] In a 10L polymerization kettle, 190 parts of desalted water, 5 parts of emulsifier (rosin soap and fatty alkyl sulfonate compound ratio 4:1 emulsifier), 0.2 parts of EDTA sodium iron salt, 0.3 parts of benzylnaphthalenesulfonic acid formaldehyde condensate, 0.5 parts of potassium phosphate, 4 parts of 2,4-diphenyl-4-methyl-1-pentene, 26 parts of styrene, 12 parts of sulfonic acid ester monomer and 0.05 parts of isoascorbic acid were added. After the addition was completed, nitrogen was replaced three times, 60 parts of butadiene were added, and then 0.153 parts of isopropyl tert-butyl peroxide were added at 15°C for polymerization.

[0107] When the monomer conversion rate of butadiene, styrene and sulfonic acid ester monomer reaches 25%, 1 part of sulfonic acid ester monomer is added; when the monomer conversion rate reaches 50%, 0.5 parts of emulsifier and 0.6 parts of 2,4-diphenyl-4-methyl-1-pentene are added; when the monomer conversion rate reaches 65%, 1 part of sulfonic acid ester monomer is added. When the monomer conversion rate reaches 85%, 0.05 parts of isopropylhydroxylamine are added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 5 hours to obtain ester-containing styrene butadiene latex. After condensation, washing and drying, the high-performance liquid styrene butadiene rubber containing sulfonic acid and ester groups can be obtained.

[0108] Comparative Example 3

[0109] Compared with Example 3, Comparative Example 3 adopts a method of adding the sulfonic acid ester monomer once, and the other polymerization process conditions remain unchanged. The specific S2 is as follows:

[0110] In a 10L polymerization kettle, 190 parts of desalted water, 5 parts of emulsifier (rosin soap and fatty alkyl sulfonate, 4:1 emulsifier), 0.2 parts of EDTA sodium iron salt, 0.3 parts of benzylnaphthalenesulfonic acid formaldehyde condensate, 0.5 parts of potassium phosphate, 4 parts of 2,4-diphenyl-4-methyl-1-pentene, 26 parts of styrene, 14 parts of sulfonic acid ester monomer and 0.05 parts of isoascorbic acid were added. After the addition was completed, nitrogen was replaced three times. After 60 parts of butadiene were added, 0.15 parts of isopropyl tert-butyl peroxide were added at 15°C for polymerization.

[0111] When the monomer conversion rate of butadiene, styrene and sulfonic acid ester monomers reaches 50%, 0.5 parts of emulsifier, 0.003 parts of isopropyl tert-butyl peroxide and 0.6 parts of 2,4-diphenyl-4-methyl-1-pentene are added. When the monomer conversion rate reaches 85%, 0.05 parts of isopropyl hydroxylamine are added to terminate the reaction and discharge the material. After discharge, the material is degassed in a degassing tower for 5 hours to obtain ester-containing styrene butadiene latex. After coagulation, washing and drying, the high-performance liquid styrene butadiene rubber containing sulfonic acid and ester groups can be obtained.

[0112] The properties of the liquid styrene-butadiene rubber prepared in Comparative Examples 1 to 3 are compared with those in Example 3 and are shown in Table 2.

[0113] Table 2

[0114] Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Bound styrene content, wt% 24.7 21.6 23.2 24.3 Sulfonic acid ester content, wt% 12.7 7.4 9.6 8.3 Molecular weight, Mn 3956 5138 3864 4016 Mooney viscosity, Pa·s@25℃ 49.8 61.3 48.6 50.2

[0115] Comparative Example 1 is compared with Example 3 to find that the combined styrene content and the sulfonic acid ester content are reduced accordingly, and the molecular weight and Mooney viscosity are increased accordingly. This is because the one-time feeding method is adopted, which leads to the accelerated polymerization of styrene in the initial stage of the polymerization reaction, thereby making the styrene distribution on the polymer chain uneven and causing the combined rate of the sulfonic acid ester monomer to decrease. At the same time, due to the one-time addition of the molecular weight regulator and the emulsifier, the molecular weight control is not good.

[0116] By comparing Comparative Example 2 with Example 3, it can be found that the content of styrene and the content of sulfonic acid ester are reduced accordingly. This is because the initiator is added once, which leads to a faster reaction in the early stage of the polymerization reaction and a slower reaction in the later stage. According to field tests, the time required for the reaction of Comparative Example 2 is much greater than that of Example 3.

[0117] Comparative Example 3 Compared with Example 3, it can be found that the content of bound styrene has not decreased significantly, but the content of sulfonate ester has been greatly reduced. This is because the reactivity rate of sulfonate ester is weaker than that of styrene and butadiene. Therefore, adding sulfonate ester at one time will make the sulfonate ester chain segments unevenly distributed in the polymer molecular chain and reduce the binding rate, thereby resulting in a decrease in content.

[0118] In order to further characterize the application performance of the obtained liquid styrene-butadiene rubber, the present invention provides an application as an epoxy resin toughening agent, including but not limited to a toughening agent. The modified high-performance liquid styrene-butadiene rubber prepared in Example 3 was tested for epoxy resin toughening, and the ordinary liquid styrene-butadiene rubber of Comparative Example 4 without adding sulfonic acid ester monomer was used as a control, and the addition amount was 5wt%. The thermal decomposition temperature and erosion wear performance of the cured epoxy resin after toughening were tested, and the test results are shown in Tables 3 and 4, respectively. Figure 3 shown.

[0119] Comparative Example 4

[0120] Compared with Example 3, no sulfonic acid ester monomer is added in Comparative Example 4. The specific S2 is as follows:

[0121] In a 10L polymerization kettle, 190 parts of desalted water, 5 parts of emulsifier (rosin soap and fatty alkyl sulfonate with a compound ratio of 4:1 emulsifier), 0.2 parts of EDTA sodium iron salt, 0.3 parts of benzylnaphthalenesulfonic acid formaldehyde condensate, 0.5 parts of potassium phosphate, 4 parts of 2,4-diphenyl-4-methyl-1-pentene, 26 parts of styrene and 0.05 parts of isoascorbic acid were added. After the addition was completed, nitrogen was replaced three times, 74 parts of butadiene were added, and then 0.15 parts of isopropyl tert-butyl peroxide were added at 15°C for polymerization.

[0122] When the conversion rate of butadiene and styrene monomers reaches 50%, 0.5 parts of emulsifier, 0.003 parts of isopropyl tert-butyl peroxide and 0.6 parts of 2,4-diphenyl-4-methyl-1-pentene are added; when the monomer conversion rate reaches 85%, 0.05 parts of isopropyl hydroxylamine are added to terminate the reaction and discharge the material; after discharge, the material is degassed in a degassing tower for 5 hours to obtain ester-containing styrene butadiene latex; after coagulation, washing and drying, the common liquid styrene butadiene rubber can be obtained.

[0123] Table 3

[0124] Thermal decomposition temperature, Tmax, ℃ Epoxy resin cured product 373 Comparative Example 4: Modified Epoxy Resin Cured Material 365 Example 3: Modified epoxy resin cured product 387

[0125] From the comparative data in Table 3, it can be seen that the thermal decomposition temperature of the pure epoxy resin cured product is 373°C, and the thermal decomposition temperature of the modified epoxy resin cured product of Comparative Example 4 is 365°C. This is because the ordinary liquid styrene-butadiene rubber and the epoxy resin undergo a cross-linking reaction to form an incompletely cross-linked network structure. At the same time, since the thermal stability of the liquid styrene-butadiene rubber is relatively weaker than that of the epoxy resin, the thermal decomposition temperature of the ordinary liquid styrene-butadiene rubber modified epoxy resin cured product is reduced. However, the thermal decomposition temperature of the modified epoxy resin cured product of Example 3 is 387°C, which is higher than 373°C of the pure epoxy resin cured product. This is because the introduction of the ester structure improves the heat resistance of the polymer.

[0126] Depend on Figure 3 It can be seen that as the amount of liquid styrene butadiene rubber prepared in Comparative Example 4 and Example 3 increases, the erosion wear rate decreases and the wear resistance gradually increases, but the epoxy resin modified by the modified high-performance liquid styrene butadiene rubber in Example 3 has better wear resistance, which is because the addition of sulfonic acid groups further improves the mechanical properties of the material. At the same time, it is found that the wear resistance will weaken when a certain amount is added, because the wear resistance of the cured product is not only affected by the modifier, but also by the bonding performance, so when a certain amount is added, the wear resistance of the cured product will weaken.

[0127] In order to further characterize the application performance of the obtained modified high-performance liquid styrene butadiene rubber, the modified high-performance liquid styrene butadiene rubber prepared in Example 3 was used to replace rubber processing oil in the preparation of tire rubber compound, using the mixing formula in Table 4.

[0128] Table 4

[0129] Components Formula 1, g Recipe 2, g Solution Polymerized Styrene Butadiene Rubber 60 60 Butadiene rubber 40 40 8# Carbon Black 7.5 7.5 sulfur 0.5 0.5 Accelerator TMTD 3.0 3.0 Processing oil 20.0 0.0 Example 3 0.0 20.0 Stearic acid 1.0 1.0 Zinc Oxide 5.0 5.0

[0130] The properties of the vulcanized rubber obtained by processing according to Table 4 are shown in Table 5.

[0131] Table 5

[0132] project Recipe 1 Recipe 2 Tensile strength, MPa 14.54 16.32 Tear strength, MPa 43.15 45.76 Shore A hardness 73 74 <![CDATA[DIN wear volume, cm 3 > 0.173 0.064

[0133] It can be seen from Table 5 that after the modified high-performance liquid styrene butadiene rubber is used to replace the rubber processing operating oil, the tensile strength and tear strength of the tire vulcanized rubber are improved, and the wear resistance is enhanced. Therefore, the modified high-performance liquid styrene butadiene rubber can be used to replace the rubber processing operating oil, thereby improving the physical and mechanical properties of the tread rubber.

[0134] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A liquid styrene-butadiene rubber, wherein: The polymerization monomers of the liquid styrene-butadiene rubber include butadiene, styrene and sulfonic acid ester monomers; The structural formula of the sulfonic acid ester monomer is: Based on 100 parts of the total weight of the butadiene, styrene and sulfonic acid group-containing ester monomer, the weight parts of each monomer are: 50-75 parts of butadiene, 20-30 parts of styrene, and 5-24 parts of sulfonic acid group-containing ester monomer.

2. The liquid styrene-butadiene rubber according to claim 1, wherein The liquid styrene-butadiene rubber is prepared by emulsion copolymerization of butadiene, styrene and sulfonic acid ester monomers.

3. The liquid styrene-butadiene rubber according to claim 1, wherein The liquid styrene-butadiene rubber contains 3wt% to 18wt% of the sulfonic acid ester monomer structure; The Mooney viscosity of the liquid styrene-butadiene rubber at 25° C. is 40-60 Pa·s, and the molecular weight Mn ranges from 3000 to 5000.

4. A method for preparing the liquid styrene-butadiene rubber according to any one of claims 1 to 3, wherein: The preparation method comprises the following steps: Based on 100 parts of the total weight of butadiene, styrene and sulfonic acid ester monomer, 160-220 parts of desalted water, 4-8 parts of emulsifier, 0.1-0.3 parts of reducing agent, 0.1-0.4 parts of diffusing agent, 0.4-0.8 parts of electrolyte, 3-6 parts of molecular weight regulator, 20-30 parts of styrene, 3-20 parts of sulfonic acid ester monomer and 0.01-0.1 parts of deoxidizer are added into a reaction container. After the addition is completed, 50-75 parts of butadiene are added in a protective gas atmosphere, and stirred for pre-emulsification, and then 0.1-0.2 parts of initiator are added for polymerization reaction; When the three monomers of butadiene, styrene and sulfonic acid ester monomer reach a certain monomer conversion rate, emulsifier, initiator, molecular weight regulator and sulfonic acid ester monomer are added respectively. When the monomer conversion rate reaches 82-87%, 0.05-0.2 parts of terminator are added to terminate the reaction, and then degassing, condensation, washing and drying are carried out to obtain the liquid styrene-butadiene rubber.

5. The preparation method according to claim 4, wherein When the three monomers of butadiene, styrene and sulfonic acid ester monomer reach a certain monomer conversion rate, the steps of respectively adding an emulsifier, an initiator, a molecular weight regulator and a sulfonic acid ester monomer specifically include: When the monomer conversion rate reaches 25% to 30%, add 1 to 2 parts of sulfonic acid ester monomer; when the monomer conversion rate reaches 50% to 55%, add 0.4 to 0.8 parts of emulsifier, 0.002 to 0.004 parts of initiator, and 0.5 to 0.8 parts of molecular weight regulator; when the monomer conversion rate reaches 65% to 70%, add 1 to 2 parts of sulfonic acid ester monomer.

6. The preparation method according to claim 4 or 5, wherein: The emulsifier is an anionic compound surfactant or an anionic compound surfactant; wherein the anionic compound surfactant is a compound of rosin soap and fatty alkyl sulfonate, and the compounding mass ratio is (4-5):1; the anionic compound surfactant is a compound of rosin soap and polyoxyethylene ether, and the compounding mass ratio is (3-4):1; The reducing agent is selected from at least one of sodium formaldehyde sulfoxylate, ferrous sulfate, cuprous sulfate, EDTA sodium iron salt, and EDTA sodium copper salt; The diffusant is selected from at least one of β-naphthalenesulfonate sodium formaldehyde condensate, methylnaphthalenesulfonate sodium formaldehyde condensate, and benzylnaphthalenesulfonic acid formaldehyde condensate; The electrolyte is potassium phosphate or potassium chloride; The molecular weight regulator is selected from at least one of dodecyl mercaptan, tert-dodecyl mercaptan, and 2,4-diphenyl-4-methyl-1-pentene; The deoxidizer is selected from at least one of sodium dithionite, dimethyl ketoxime and isoascorbic acid; The initiator is selected from at least one of cumene hydroperoxide, diisopropyl hydroperoxide, and isopropyl tert-butyl peroxide; The terminator is selected from at least one of hydroxylamine sulfate, diethylhydroxylamine, and isopropylhydroxylamine.

7. The preparation method according to claim 4, wherein The sulfonic acid ester monomer is prepared by the following steps: Acrylic acid, sodium isethionate, a dehydrating agent and a catalyst are added to a reaction container, and the temperature is raised under a protective gas atmosphere to carry out an esterification reaction. During the reaction, generated water and the dehydrating agent are continuously evaporated, and the dehydrating agent is separated and refluxed into the reaction container to continue the reaction. When the amount of separated water no longer increases and reaches a theoretical calculated amount, the reaction is stopped, the reaction system is filtered to obtain a filter cake, and the filter cake is subjected to reduced pressure distillation to obtain the sulfonic acid group-containing ester monomer.

8. The preparation method according to claim 7, wherein: The molar ratio of the sodium isethionate to acrylic acid is 1:(1-1.5).

9. The preparation method according to claim 7, wherein: The dehydrating agent is selected from at least one of toluene, ethylbenzene and p-toluene; the catalyst is selected from at least one of methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and 2-naphthalenesulfonic acid.

10. Use of the liquid styrene-butadiene rubber according to any one of claims 1 to 3 in tires or epoxy resin toughening agents.

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