阅读说明：本技术 甲基丁苯橡胶及其制备方法 (Methyl styrene-butadiene rubber and preparation method thereof ) 是由 侯军 殷兰 郭睿达 庞建勋 孙继德 王秀芝 李永茹 石捷强 于 2019-04-02 设计创作，主要内容包括：本发明提供了一种甲基丁苯橡胶及其制备方法。该制备方法包括：在真空和氮气置换条件下,以α-甲基苯乙烯、丁二烯、水、乳化剂、电解质、还原剂、分子量调节剂及引发剂为原料进行乳液聚合反应,得到乳液聚合产物；当乳液聚合反应体系的转化率为60～65％时,向乳液聚合反应体系中依次加入终止剂及破乳剂,得到甲基丁苯橡胶。以α-甲基苯乙烯与丁二烯为主要原料通过乳液聚合反应制备甲基丁苯橡胶,该甲基丁苯橡胶的玻璃化转变温度在-70℃以下,结合α-甲基苯乙烯的含量在8～15％,门尼粘度(ML<Sub>1+4</Sub><Sup>100℃</Sup>)35～45,且具有较高的拉伸强度和良好的环保性。(The invention provides a methyl styrene-butadiene rubber and a preparation method thereof, wherein the preparation method comprises the steps of carrying out emulsion polymerization reaction on α -methyl styrene, butadiene, water, an emulsifier, an electrolyte, a reducing agent, a molecular weight regulator and an initiator as raw materials under the conditions of vacuum and nitrogen replacement to obtain an emulsion polymerization product, sequentially adding a terminator and a demulsifier into an emulsion polymerization reaction system when the conversion rate of the emulsion polymerization reaction system is 60-65% to obtain the methyl styrene-butadiene rubber, preparing the methyl styrene-butadiene rubber by using α -methyl styrene and butadiene as main raw materials through emulsion polymerization, controlling the glass transition temperature of the methyl styrene-butadiene rubber to be below 70 ℃ below zero, controlling the content of α -methyl styrene to be 8-15%, and carrying out Mooney reactionViscosity (ML) 1+4 100℃ ) 35-45 and has higher tensile strength and good environmental protection.)

1. A preparation method of methyl styrene-butadiene rubber is characterized by comprising the following steps:

under the vacuum and nitrogen replacement condition, carrying out emulsion polymerization reaction by taking alpha-methylstyrene, butadiene, water, an emulsifier, an electrolyte, a reducing agent, a molecular weight regulator, an initiator and a terminator as raw materials to obtain an emulsion polymerization product, wherein the raw materials comprise, by weight, 15-25 parts of the alpha-methylstyrene, 75-85 parts of the butadiene, 3.5-5.0 parts of the emulsifier, 0.63-1.03 parts of the electrolyte, 0.02-0.1 part of the initiator, 0.065-0.085 part of the reducing agent, 0.2-0.30 part of the molecular weight regulator, 180-200 parts of the water and 0.35-0.5 part of the terminator;

and when the conversion rate of the emulsion polymerization reaction system is 60-65%, sequentially adding a terminator and a demulsifier into the emulsion polymerization reaction system to obtain the methyl styrene-butadiene rubber.

2. The method according to claim 1, wherein the raw material comprises, by weight, 18 to 22 parts of the α -methylstyrene, 77 to 80 parts of the butadiene, 4 to 4.5 parts of the emulsifier, 0.8 to 0.9 part of the electrolyte, 0.2 to 0.5 part of the initiator, 0.07 to 0.075 part of the reducing agent, 0.23 to 0.28 part of the molecular weight modifier, 185 to 195 parts of water, and 0.38 to 0.48 part of the terminating agent.

3. The production method according to claim 1 or 2, wherein the electrolyte is at least two selected from the group consisting of phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetate, and sodium dodecylbenzenesulfonate.

4. The production method according to claim 3, wherein the electrolyte comprises, in parts by weight: 0.2-0.3 part of phosphoric acid, 0.3-0.5 part of potassium hydroxide, 0.01-0.03 part of tetrasodium ethylene diamine tetraacetate and 0.1-0.2 part of sodium dodecyl benzene sulfonate.

5. The production method according to claim 1 or 2, wherein the reducing agent is selected from one or more of the group consisting of ferrous sulfate, sodium formaldehyde sulfoxylate, and tetrasodium ethylenediaminetetraacetate;

preferably, the reducing agent comprises 0.01-0.03 part of ferrous sulfate, 0.03-0.05 part of sodium formaldehyde sulfoxylate and 0.03-0.05 part of tetrasodium ethylenediaminetetraacetate in parts by weight.

6. The production method according to claim 1 or 2, characterized in that the terminating agent is selected from N-isopropylhydroxylamine and/or di-N-propylthiourea;

preferably, the terminator comprises 0.05 to 0.1 part by weight of the N-isopropylhydroxylamine and 0.3 to 0.4 part by weight of the di-N-propylthiourea.

7. The production method according to claim 1 or 2, characterized in that the molecular weight regulator is selected from tertiary dodecyl mercaptan and/or n-dodecyl mercaptan;

preferably, the initiator is selected from one or more of the group consisting of p-menthane hydroperoxide, p-pinane hydroperoxide and diisopropylbenzene hydroperoxide;

preferably, the emulsifier is selected from disproportionated potassium rosinate soap and/or sodium fatty acid soap.

8. The method according to claim 1, wherein the emulsion polymerization is carried out at a reaction temperature of 4 to 6 ℃ for 5 to 10min in parts by weight.

9. The method of claim 1, wherein the emulsion polymerization reaction comprises: and placing the alpha-methylstyrene, the butadiene, the water, the emulsifier, the electrolyte, the reducing agent, the molecular weight regulator and the polymer into a polymerization kettle, and adding the initiator into the polymerization kettle to carry out the polymerization reaction when the temperature of the polymerization kettle is reduced to 4-6 ℃.

10. The preparation method according to claim 1, further comprising adding the product system of the emulsion polymerization reaction into a dilute sulfuric acid solution with a concentration of 0.3-0.8 wt%, stirring, condensing, washing, and drying to obtain the methyl styrene-butadiene rubber;

preferably, the temperature in the stirring process is controlled to be 55-65 ℃, and the stirring time is 5-10 min.

11. A methyl styrene-butadiene rubber, characterized in that the methyl styrene-butadiene rubber is prepared by the preparation method of any one of claims 1 to 10.

Technical Field

The invention relates to the field of rubber, and particularly relates to methyl styrene-butadiene rubber and a preparation method thereof.

Background

Styrene Butadiene Rubber (SBR) is a copolymer rubber prepared by polymerizing butadiene and styrene, and is a general synthetic rubber with the highest yield and the highest consumption in the world as one of important Synthetic Rubber (SR) varieties.

Styrene-butadiene rubber has repeating units of butadiene and repeating units of styrene. The styrene unit provides a rigid structure for the styrene butadiene rubber, so that the styrene butadiene rubber has certain strength and wet skid resistance. Unsaturated bonds in the butadiene structure provide cross-linking bonds for styrene butadiene rubber, and the molecular chain of the butadiene rubber has certain flexibility due to the 1, 4-butadiene structure. The glass transition temperature of the styrene-butadiene rubber is closely related to the molecular structure composition of the styrene-butadiene rubber, and the glass transition temperature is reduced along with the increase of the content of butadiene in the styrene-butadiene rubber.

The methyl styrene-butadiene rubber is obtained by copolymerizing alpha-methyl styrene and butadiene, the typical properties of the raw rubber and the physical and mechanical properties of vulcanized rubber are similar to those of styrene-butadiene rubber, the application of the methyl styrene-butadiene rubber is the same as that of styrene-butadiene rubber with a corresponding grade, and the methyl styrene-butadiene rubber is mainly used for manufacturing tires and various rubber industrial products such as conveying belts, sealing gaskets and the like.

The rubber gasket generally needs to have the performances of oil resistance, acid and alkali resistance, cold and heat resistance, aging resistance and the like, and is widely applied to the industries of automobiles, electronics, chemical industry, static resistance, flame retardance, food and the like. For some special machines, due to the limitation of working environment, the rubber sealing gasket has high requirements on low temperature resistance, good compression cold resistance coefficient, high temperature oxidation resistance and certain tensile strength. Although the traditional styrene butadiene rubber can meet the low-temperature working requirement of the sealing gasket rubber, the high-temperature oxidation resistance is poor. Compared with styrene, alpha-methyl styrene contained in methyl styrene-butadiene rubber has better rigidity, and the existence of the alpha-methyl styrene provides better tensile strength and high-temperature oxidation resistance for the material. However, the research on the preparation method of α -methylstyrene is relatively rare in the art, and thus it is required to develop a method for preparing α -methylstyrene.

Disclosure of Invention

The invention mainly aims to provide methyl styrene-butadiene rubber and a preparation method thereof, and aims to solve the problem that the existing sealing material cannot meet the application requirement at high temperature.

In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a methyl styrene-butadiene rubber, the method comprising: under the vacuum and nitrogen replacement condition, carrying out emulsion polymerization reaction by taking alpha-methylstyrene, butadiene, water, an emulsifier, an electrolyte, a reducing agent, a molecular weight regulator, an initiator and a terminator as raw materials to obtain an emulsion polymerization product, wherein the raw materials comprise, by weight, 15-25 parts of alpha-methylstyrene, 75-85 parts of butadiene, 3.5-5.0 parts of the emulsifier, 0.63-1.03 parts of the electrolyte, 0.02-0.1 part of the initiator, 0.065-0.085 part of the reducing agent, 0.2-0.30 part of the molecular weight regulator, 180-200 parts of water and 0.35-0.5 part of the terminator; and when the conversion rate of the emulsion polymerization reaction system is 60-65%, sequentially adding a terminator and a demulsifier into the emulsion polymerization reaction system to obtain the methyl styrene-butadiene rubber.

Further, the raw materials comprise, by weight, 18-22 parts of alpha-methyl styrene, 77-80 parts of butadiene, 4-4.5 parts of an emulsifier, 0.8-0.9 part of an electrolyte, 0.2-0.5 part of an initiator, 0.07-0.075 part of a reducing agent, 0.23-0.28 part of a molecular weight regulator, 185-195 parts of water and 0.38-0.48 part of a terminator.

Further, the electrolyte is selected from at least two of the group consisting of phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetate, and sodium dodecylbenzenesulfonate.

Further, the electrolyte comprises the following components in parts by weight: 0.2 to 0.3 portion of phosphoric acid, 0.3 to 0.5 portion of potassium hydroxide, 0.01 to 0.03 portion of tetrasodium ethylene diamine tetraacetate and 0.1 to 0.2 portion of sodium dodecyl benzene sulfonate.

Further, the reducing agent is selected from one or more of the group consisting of ferrous sulfate, sodium formaldehyde sulfoxylate and tetrasodium ethylenediaminetetraacetate; preferably, the reducing agent comprises 0.01-0.03 part of ferrous sulfate, 0.03-0.05 part of sodium formaldehyde sulfoxylate and 0.03-0.05 part of tetrasodium ethylenediamine tetraacetate in parts by weight.

Further, the terminating agent is selected from N-isopropyl hydroxylamine and/or di-N-propyl thiourea; preferably, the terminator comprises 0.05 to 0.1 part by weight of N-isopropylhydroxylamine and 0.3 to 0.4 part by weight of di-N-propylthiourea.

Further, the molecular weight regulator is selected from tertiary dodecyl mercaptan and/or n-dodecyl mercaptan; preferably, the initiator is selected from one or more of the group consisting of p-menthane hydroperoxide, p-pinane hydroperoxide and diisopropylbenzene hydroperoxide; preferably, the emulsifier is selected from disproportionated potassium rosinate soap and/or sodium fatty acid soap.

Further, the reaction temperature of the emulsion polymerization reaction is 4-6 ℃ and the reaction time is 5-10 min in parts by weight.

Further, the emulsion polymerization reaction comprises: placing alpha-methyl styrene, butadiene, water, an emulsifier, an electrolyte, a reducing agent and a molecular weight regulator into a polymerization kettle, and adding an initiator into the polymerization kettle to carry out polymerization reaction when the temperature of the polymerization kettle is reduced to 4-6 ℃.

Further, the preparation method comprises the steps of adding a product system of the emulsion polymerization reaction into a dilute sulfuric acid solution with the concentration of 0.3-0.8 wt%, stirring, coagulating, washing and drying to obtain the methyl styrene-butadiene rubber; preferably, the temperature in the stirring process is controlled to be 55-65 ℃, and the stirring time is 5-10 min.

The application also provides methyl styrene-butadiene rubber which is prepared by the preparation method.

According to the technical scheme, α -methyl styrene and butadiene are used as main raw materials to prepare methyl styrene-butadiene rubber through emulsion polymerization, and the styrene-butadiene rubber molecule can be changed by controlling the dosage of each componentThe glass transition temperature of the methyl styrene-butadiene rubber is below-70 ℃, the content of the combined α -methyl styrene is 8-15%, and the Mooney viscosity (ML) is₁₊₄ ^100℃) 35-45 and has higher tensile strength. The prepared product has no nitrosamine parent, and can not generate nitrosamine, so that the product has good environmental protection property and conforms to the EU related regulation TRGS 552. In conclusion, the methyl styrene-butadiene rubber prepared by the preparation method has the advantages of low glass transition temperature, high tensile strength, excellent environmental protection property, excellent processability and the like.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As described in the background section, the prior art sealing materials have not met the application requirements at high temperatures. In order to solve the technical problem, the application provides a preparation method of methyl styrene-butadiene rubber, which comprises the following steps: under the vacuum and nitrogen replacement condition, carrying out emulsion polymerization reaction by taking alpha-methyl styrene, butadiene, water, an emulsifier, an electrolyte, a reducing agent, a molecular weight regulator, an initiator and a terminator as raw materials to obtain an emulsion polymerization product, wherein the raw materials comprise, by weight, 15-25 parts of alpha-methyl styrene, 75-85 parts of butadiene, 3.5-5.0 parts of the emulsifier, 0.63-1.03 parts of the electrolyte, 0.02-0.1 part of the initiator, 0.065-0.085 part of the reducing agent, 0.2-0.30 part of the molecular weight regulator, 180-200 parts of water and 0.35-0.5 part of the terminator. And when the conversion rate of the emulsion polymerization reaction system is 60-65%, sequentially adding a terminator and a demulsifier into the emulsion polymerization reaction system to obtain the methyl styrene-butadiene rubber.

In the preparation method, α -methyl styrene and butadiene are used as main raw materials to prepare the methyl styrene-butadiene rubber through emulsion polymerization, and the purposes of changing the content of combined α -styrene in the molecular structure of the styrene-butadiene rubber and adjusting the Mooney of the product can be realized by controlling the dosage of each componentThe transformation temperature is below-70 ℃, the content of combined α -methyl styrene is 8-15%, and the Mooney viscosity (ML) is₁₊₄ ^100℃) 35-45 and has higher tensile strength. The prepared product has no nitrosamine parent, and can not generate nitrosamine, so that the product has good environmental protection property and conforms to the EU related regulation TRGS 552. In conclusion, the methyl styrene-butadiene rubber prepared by the preparation method has the advantages of low glass transition temperature, high tensile strength, excellent environmental protection property, excellent processability and the like.

The methyl styrene-butadiene rubber prepared from the raw materials has excellent comprehensive performance, so that the methyl styrene-butadiene rubber has a wider application range. In a preferred embodiment, the raw materials comprise, by weight, 18 to 22 parts of alpha-methylstyrene, 77 to 80 parts of butadiene, 4 to 4.5 parts of an emulsifier, 0.8 to 0.9 part of an electrolyte, 0.2 to 0.5 part of an initiator, 0.07 to 0.075 part of a reducing agent, 0.23 to 0.28 part of a molecular weight regulator, 185 to 195 parts of water and 0.38 to 0.48 part of a terminator. The amount of the raw material for preparation includes, but is not limited to, the above range, and it is preferable to further improve the tensile strength and processability of the methyl styrene-butadiene rubber by limiting the amount to the above range.

The electrolyte may be selected from those commonly used in the art. In a preferred embodiment, the electrolyte includes, but is not limited to, at least two of the group consisting of phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetate, and sodium dodecylbenzenesulfonate. Two electrolytes can form a stable electrolyte system, so that the reaction efficiency of emulsion polymerization reaction is improved, and the generation of nitrite is reduced. More preferably, the electrolyte comprises, in parts by weight: 0.2 to 0.3 portion of phosphoric acid, 0.3 to 0.5 portion of potassium hydroxide, 0.01 to 0.03 portion of tetrasodium ethylene diamine tetraacetate and 0.1 to 0.2 portion of sodium dodecyl benzene sulfonate.

In the above synthesis method, the reducing agent may be selected from those commonly used in the art. In a preferred embodiment, the reducing agent includes, but is not limited to, one or more of the group consisting of ferrous sulfate, sodium formaldehyde sulfoxylate, and tetrasodium ethylenediaminetetraacetate. The selection of the reducing agents is beneficial to improving the oxidation resistance of the methyl styrene butadiene rubber. In order to further improve the oxidation resistance of the methyl styrene butadiene rubber, more preferably, the reducing agent comprises one or more of the group consisting of 0.01 to 0.03 parts by weight of ferrous sulfate, 0.03 to 0.05 parts by weight of sodium formaldehyde sulfoxylate and 0.03 to 0.05 parts by weight of tetrasodium ethylene diamine tetraacetate.

In the above synthesis method, the terminator may be selected from those commonly used in the art. In a preferred embodiment, the terminating agent includes, but is not limited to, N-isopropylhydroxylamine and/or di-N-propylthiourea. The use of the above-mentioned specific composition of the terminating agent is advantageous in improving the terminating efficiency of the emulsion polymerization reaction. More preferably, the terminator comprises 0.05 to 0.1 part by weight of N-isopropylhydroxylamine and 0.3 to 0.4 part by weight of di-N-propylthiourea.

In the above synthesis method, the molecular weight regulator may be selected from those commonly used in the art. In a preferred embodiment, the molecular weight regulator includes, but is not limited to, tertiary dodecyl mercaptan and/or n-dodecyl mercaptan. The molecular weight regulator is favorable for more accurately controlling the molecular weight of the methyl styrene-butadiene rubber.

Preferably, the initiator includes, but is not limited to, one or more of the group consisting of p-menthane hydroperoxide, p-pinane hydroperoxide and diisopropylbenzene hydroperoxide. The initiators include, but are not limited to, the above initiators, which are selected to facilitate a reduction in initiation time and an increase in initiation efficiency.

Preferably, the emulsifier includes, but is not limited to, disproportionated potassium rosinate soap and/or sodium fatty acid soap. The types of the emulsifiers include but are not limited to the above emulsifiers, and the emulsifiers are selected to be beneficial to improving the stability of the emulsion environment in the emulsion polymerization reaction process, and further beneficial to improving the yield of the methyl styrene butadiene rubber.

In a preferred embodiment, the emulsion polymerization reaction is carried out at a reaction temperature of 4 to 6 ℃ for 5 to 10min in parts by weight. The polymerization temperature and reaction time include, but are not limited to, the above ranges, and it is advantageous to further improve the reaction efficiency of the emulsion polymerization by limiting the temperature and reaction time to the above ranges.

More preferably, the emulsion polymerization reaction comprises: placing alpha-methyl styrene, butadiene, water, an emulsifier, an electrolyte, a reducing agent and a molecular weight regulator into a polymerization kettle, and adding an initiator into the polymerization kettle to carry out polymerization reaction when the temperature of the polymerization kettle is reduced to 4-6 ℃.

In order to reduce the content of impurities in the methyl styrene-butadiene rubber, in a preferred embodiment, the preparation method further comprises adding a product system of the emulsion polymerization reaction into a dilute sulfuric acid solution with the concentration of 0.3-0.8 wt%, stirring, condensing, washing, and drying to obtain the methyl styrene-butadiene rubber. Preferably, the temperature in the stirring process is controlled to be 55-65 ℃, and the stirring time is 5-10 min. Limiting the temperature and time of the stirring process within the above ranges is beneficial to further improving the removal rate of impurities in the methyl styrene-butadiene rubber.

The application also provides methyl styrene-butadiene rubber which is prepared by the preparation method.

α -methyl styrene and butadiene are used as main raw materials to prepare methyl styrene-butadiene rubber through emulsion polymerization, the glass transition temperature of the methyl styrene-butadiene rubber is below-70 ℃, the content of combined α -methyl styrene is 8-15%, and the Mooney viscosity (ML) is₁₊₄ ^100℃) 35-45 and has higher tensile strength. The prepared product has no nitrosamine parent, and can not generate nitrosamine, so that the product has good environmental protection property and conforms to the EU related regulation TRGS 552. In conclusion, the methyl styrene-butadiene rubber prepared by the preparation method has the advantages of low glass transition temperature, high tensile strength, excellent environmental protection property, excellent processability and the like.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.