阅读说明：本技术 一种高伯位溴溴化丁基橡胶及其合成方法 (High-primary-position brominated butyl rubber and synthesis method thereof ) 是由 韩飞 谢晴 张�杰 陈立财 栾波 王耀伟 任学斌 于 2021-11-02 设计创作，主要内容包括：本发明提供了一种高伯位溴溴化丁基橡胶,所述高伯位溴溴化丁基橡胶中,所述伯位溴结构占所述溴化丁基橡胶中异戊二烯单元总摩尔数的摩尔含量为20％～30％；所述高伯位溴溴化丁基橡胶由溶液法制备得到。本发明提供的溶液法合成的高伯位溴溴化丁基橡胶,能够有效的控制溴化丁基橡胶溴代结构,较高的伯位溴结构大大提高了硫化速率,在一定程度上缩短了下游制品的处理时间,而且拉伸、密封等性能均满足汽车无内胎轮胎、医用胶塞等工业品使用要求。(The invention provides a high-primary-position bromobutyl rubber, wherein the mole content of a primary-position bromine structure in the high-primary-position bromobutyl rubber in the total mole number of isoprene units in the bromobutyl rubber is 20-30%; the high-primary-position bromobutyl rubber is prepared by a solution method. The high-primary-position bromine brominated butyl rubber synthesized by the solution method provided by the invention can effectively control the bromination structure of the brominated butyl rubber, the high-primary-position bromine structure greatly improves the vulcanization rate, the processing time of downstream products is shortened to a certain extent, and the performances of stretching, sealing and the like meet the use requirements of industrial products such as automobile tubeless tires, medical rubber plugs and the like.)

1. The high-primary-position bromobutyl rubber is characterized in that in the high-primary-position bromobutyl rubber, the mole content of the primary-position bromine structure in the total mole number of isoprene units in the bromobutyl rubber is 20-30%;

the high-primary-position bromobutyl rubber is prepared by a solution method.

2. The high primary bromobutyl rubber of claim 1 wherein the primary bromine structure comprises 30 to 50 percent of the mole content of primary and secondary bromine structures;

in the high primary bromine brominated butyl rubber, the molar weight of a primary bromine structure and a secondary bromine structure in the brominated butyl rubber is 0.85-1.05%;

the normal vulcanization time t90 of the high-primary-position bromobutyl rubber is 8-9.5 min.

3. The high-primary-position bromobutyl rubber of claim 1, wherein said high-primary-position bromobutyl rubber comprises, in parts by mass of the raw materials:

the structural stabilizer includes the first structural stabilizer and the second structural stabilizer.

4. A synthetic method of high-primary-position bromobutyl rubber is characterized by comprising the following steps:

1) mixing the butyl rubber organic solution with water to obtain a mixed glue solution;

2) mixing the mixed glue solution obtained in the step with the liquid bromine organic solution again, and carrying out bromination reaction under the condition of no light;

3) adding an alkaline solution into the reaction system in the step for pre-neutralization, then adding the alkaline solution again, and neutralizing again to obtain a brominated butyl rubber glue solution;

4) and adding a structural stabilizer and an antioxidant into the brominated butyl rubber glue solution obtained in the step to obtain the high-primary brominated butyl rubber.

5. The synthesis method according to claim 4, wherein the mass concentration of the butyl rubber organic solution is 10-25%;

the organic solvent in the butyl rubber organic solution comprises a weak polar and/or non-polar alkane solvent;

in the step 1), one or more of inorganic peroxide, high-valent chlorine salt and high-valent bromine salt are also added;

the mass of the water accounts for 0.1-10% of the mass of the butyl rubber organic solution.

6. The synthesis method according to claim 5, wherein the organic solvent in the butyl rubber organic solution comprises n-hexane and/or isohexane;

the molar ratio of one or more of the inorganic peroxide, the high-valence chloride salt and the high-valence bromide salt to the liquid bromine is (0.05-2): 1;

the addition mode of one or more of the inorganic peroxide, the high-valence chlorine salt and the high-valence bromine salt comprises a mode of forming an aqueous solution with water.

7. The synthesis method of claim 5, wherein the inorganic peroxide comprises hydrogen peroxide;

the high valent chlorine salt comprises sodium hypochlorite;

the high-valence bromine salt comprises sodium bromate.

8. The method of synthesis of claim 4, wherein the liquid bromine organic solution comprises a liquid bromine alkane solution;

the molar ratio of the liquid bromine to the isoprene unit in the butyl rubber is (0.4-1.0): 1;

the bromination reaction time is 5-20 min;

the temperature of the bromination reaction is 20-60 ℃;

the mode of the bromination reaction includes carrying out the reaction with stirring.

9. The method of synthesis of claim 4, wherein the basic solution comprises one or more of a hydroxide solution of an alkali metal, a hydroxide solution of an alkaline earth metal, and a strong base weak acid salt solution;

the alkaline solution comprises a sodium hydroxide solution and/or a sodium carbonate solution;

the mass concentration of the alkaline solution is 0.5-5%;

the pre-neutralization time is 0.1-5 min.

10. The synthesis method according to claim 4, wherein in the pre-neutralization step, the mass of the added alkaline solution accounts for 5-95% of the mass of the total alkaline solution;

in the pre-neutralization step, the ratio of the molar weight of the solute of the added alkaline solution to the molar weight of the bromine simple substance is (1-90): 100, respectively;

the mass ratio of the alkaline solution added in the pre-neutralization to the total alkaline solution is positively correlated with the amount of the liquid bromine;

the pH value after the secondary neutralization is 6.5-8.0;

and the time for neutralizing again is 0.5-3 min.

Technical Field

The invention relates to the technical field of synthesis of brominated butyl rubber, in particular to high-primary-position brominated butyl rubber and a synthesis method thereof.

Background

Brominated butyl rubber (BIIR) is an isobutylene-isoprene copolymer elastomer containing active bromine, and has the advantages of high vulcanization speed, good mutual viscosity and compatibility, capability of being vulcanized by zinc oxide alone and the like. The brominated butyl rubber mainly contains butyl rubber with three structures, namely an unbrominated butyl rubber structure (structure I type), a brominated secondary allyl structure (structure II type) and a brominated primary allyl structure (structure III type), wherein the III type is more stable. Brominated butyl rubber has a substantially saturated backbone of butyl rubber, and therefore has many of the performance characteristics of butyl polymers, such as higher physical strength, better damping, low permeability, aging resistance, and weathering resistance. The invention and use of halogenated butyl rubber innerliners have in many respects led to modern radial tires. The use of such polymers in tire innerliner compounds can improve the holding pressure performance, improve the adhesion between the innerliner and the carcass, and improve the durability of the tire. Brominated butyl rubber has thus gradually replaced conventional butyl rubber in a variety of applications, such as industrial products like radial tires, heat resistant inner tubes, container liners, pharmaceutical stoppers and machine liners. And the brominated butyl rubber is an irreplaceable raw material for manufacturing tubeless tires, is also an essential raw material for medical rubber products, and belongs to strategic materials.

With the development of tubeless tires and medical rubber plug butylated products in China, the demand of the market for brominated butyl rubber is continuously increased. However, at present, domestic brominated butyl rubber is mainly used for middle and low-end field supply, and more high-quality brominated butyl rubber still needs to depend on import.

Therefore, the development of a novel preparation process of brominated butyl rubber for producing high-quality brominated butyl rubber has important practical significance for future popularization of domestic brominated butyl rubber, and is one of the problems to be solved urgently by a plurality of research and development type manufacturers and front-line researchers in the industry.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a high-primary-position bromobutyl rubber and a synthesis method thereof, and the method for synthesizing the high-primary-position bromobutyl rubber by a solution method provided by the present invention can effectively control the bromination structure of the bromobutyl rubber, so that the primary-position bromine structure reaches about 30%, and the method has the advantages of mild conditions, simple process, and contribution to industrial production, popularization and application.

The invention provides a high-primary-position bromobutyl rubber, wherein the mole content of a primary-position bromine structure in the high-primary-position bromobutyl rubber in the total mole number of isoprene units in the bromobutyl rubber is 20-30%;

the high-primary-position bromobutyl rubber is prepared by a solution method.

Preferably, in the high primary bromine brominated butyl rubber, the molar content of primary bromine structures in the primary bromine structures and secondary bromine structures is 30-50%;

in the high primary bromine brominated butyl rubber, the molar weight of a primary bromine structure and a secondary bromine structure in the brominated butyl rubber is 0.85-1.05%;

the normal vulcanization time t90 of the high-primary-position bromobutyl rubber is 8-9.5 min.

Preferably, the high-primary-position bromobutyl rubber comprises the following raw materials in parts by weight:

the structural stabilizer includes the first structural stabilizer and the second structural stabilizer.

The invention also provides a synthesis method of the high-primary-position bromobutyl rubber, which comprises the following steps:

1) mixing the butyl rubber organic solution with water to obtain a mixed glue solution;

2) mixing the mixed glue solution obtained in the step with the liquid bromine organic solution again, and carrying out bromination reaction under the condition of no light;

3) adding an alkaline solution into the reaction system in the step for pre-neutralization, then adding the alkaline solution again, and neutralizing again to obtain a brominated butyl rubber glue solution;

4) and adding a structural stabilizer and an antioxidant into the brominated butyl rubber glue solution obtained in the step to obtain the high-primary brominated butyl rubber.

5. The synthesis method according to claim 4, wherein the mass concentration of the butyl rubber organic solution is 10-25%;

the organic solvent in the butyl rubber organic solution comprises a weak polar and/or non-polar alkane solvent;

in the step 1), one or more of inorganic peroxide, high-valent chlorine salt and high-valent bromine salt are also added;

the mass of the water accounts for 0.1-10% of the mass of the butyl rubber organic solution.

Preferably, the organic solvent in the butyl rubber organic solution comprises n-hexane and/or isohexane;

the molar ratio of one or more of the inorganic peroxide, the high-valence chloride salt and the high-valence bromide salt to the liquid bromine is (0.05-2): 1;

the addition mode of one or more of the inorganic peroxide, the high-valence chlorine salt and the high-valence bromine salt comprises a mode of forming an aqueous solution with water.

Preferably, the inorganic peroxide comprises hydrogen peroxide;

the high valent chlorine salt comprises sodium hypochlorite;

the high-valence bromine salt comprises sodium bromate.

Preferably, the liquid bromine organic solution comprises a liquid bromine alkane solution;

the molar ratio of the liquid bromine to the isoprene unit in the butyl rubber is (0.4-1.0): 1;

the bromination reaction time is 5-20 min;

the temperature of the bromination reaction is 20-60 ℃;

the mode of the bromination reaction includes carrying out the reaction with stirring.

Preferably, the alkaline solution comprises one or more of an alkali metal hydroxide solution, an alkaline earth metal hydroxide solution and a strong base weak acid salt solution;

the alkaline solution comprises a sodium hydroxide solution and/or a sodium carbonate solution;

the mass concentration of the alkaline solution is 0.5-5%;

the pre-neutralization time is 0.1-5 min.

Preferably, in the pre-neutralization step, the mass ratio of the added alkaline solution to the total alkaline solution is 5-95%;

in the pre-neutralization step, the ratio of the molar weight of the solute of the added alkaline solution to the molar weight of the bromine simple substance is (1-90): 100, respectively;

the mass ratio of the alkaline solution added in the pre-neutralization to the total alkaline solution is positively correlated with the amount of the liquid bromine;

the pH value after the secondary neutralization is 6.5-8.0;

and the time for neutralizing again is 0.5-3 min.

The invention provides a high-primary-position bromobutyl rubber, wherein the mole content of a primary-position bromine structure in the high-primary-position bromobutyl rubber in the total mole number of isoprene units in the bromobutyl rubber is 20-30%; the high-primary-position bromobutyl rubber is prepared by a solution method. Compared with the prior art, the invention aims at the current situation that the existing brominated butyl rubber is mainly used for supplying in the middle and low-end fields, and more high-quality brominated butyl rubber is urgently needed in the industry. The invention creatively provides high-primary-position bromine brominated butyl rubber synthesized by a solution method, wherein the molar content of a primary-position bromine structure in the brominated butyl rubber in the total mole number of isoprene units can reach about 30%. The high-primary-position bromine brominated butyl rubber synthesized by the solution method provided by the invention can effectively control the bromination structure of the brominated butyl rubber, the high-primary-position bromine structure greatly improves the vulcanization rate, and the treatment time of downstream products is shortened to a certain extent.

The invention uses weak polar or non-polar alkane as solvent to prepare brominated butyl rubber by solution method, mainly using¹H-NMR specifically analyzed the bromine content and microstructure of the brominated butyl rubber. The method comprises the steps of firstly adding oxidant solution with a certain proportion into butyl rubber solution, and then mixing the oxidant solution with the butyl rubber solutionThe bromine alkane solution is mixed for bromination reaction, alkaline solution is added after the reaction to lead the system to be neutral or alkalescent, and the alkaline solution is added by a two-step method, and finally brominated butyl rubber with primary bromine structure content of about 30 percent is obtained by post-treatment, the bromine utilization rate reaches more than 90 percent, and the rubber has faster vulcanization rate, and the performances of stretching, sealing and the like which meet the use requirements of industrial products such as automobile tubeless tires, medical rubber plugs and the like.

Compared with the existing similar reaction process, the method has the advantages that the oxidant with a certain proportion is added into the glue solution before bromination, the bromine utilization rate is improved, the production cost is greatly saved, the reaction condition is easier to realize, particularly, the water environment is easier to realize, the bromination time is more flexible, and the industrial application is facilitated.

Experimental results show that Mooney degradation of the high-primary-position bromobutyl rubber synthesized by the method is about 2-3 (ML (1+8),125 ℃), the high-primary-position bromobutyl rubber is similar to common bromobutyl rubber, the primary-position bromine structure accounts for 20-30% of the total mole number of isoprene units in the bromobutyl rubber, the vulcanization rate T90 is about 8-9 min, and the product performance can meet the use requirements of products such as automobile tires, medical rubber plugs and the like.

Drawings

FIG. 1 shows the nuclear magnetic spectrum comparison of high-primary brominated butyl rubber prepared by the invention and common butyl rubber.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.

All the raw materials of the present invention are not particularly limited in their purity, and the present invention preferably employs purity requirements that are conventional in the art of analytical purification or molecular sieve catalyst preparation.

All the raw materials, the marks and the acronyms thereof belong to the conventional marks and acronyms in the field, each mark and acronym is clear and definite in the field of related application, and the raw materials can be purchased from the market or prepared by a conventional method by the technical staff in the field according to the marks, the acronyms and the corresponding application.

The invention provides a high-primary-position bromobutyl rubber, wherein the mole content of a primary-position bromine structure in the high-primary-position bromobutyl rubber in the total mole number of isoprene units in the bromobutyl rubber is 20-30%;

the high-primary-position bromobutyl rubber is prepared by a solution method.

In the present invention, the brominated butyl rubber mainly contains butyl rubber with three structures, an unbrominated butyl rubber structure (structure I type), a brominated secondary allyl structure (structure II type, secondary structure containing secondary halogen atom in halogenated butyl rubber) and a brominated primary allyl structure (structure III type, primary structure containing primary halogen atom in halogenated butyl rubber), wherein the structural formulas of type II and III are as follows:

in the invention, the molar content of the primary bromine structure in the total moles of isoprene units in the brominated butyl rubber is 20-30%, preferably 22-29%, and more preferably 24-28%. It is to be noted that the molar content is a primary bromine structure, i.e., the content of form III is the total number of moles of form I, form II and form III.

In the high primary bromine-brominated butyl rubber, the molar content of the primary bromine structure in the primary bromine structure and the secondary bromine structure is preferably 30 to 50%, more preferably 33 to 47%, more preferably 36 to 44%, and more preferably 39 to 41%.

In the present invention, in the high primary brominated butyl rubber, the molar amount of the primary bromine structure and the secondary bromine structure in the brominated butyl rubber is preferably 0.85 to 1.05%, more preferably 0.89 to 1.01%, and still more preferably 0.93 to 0.97%. I.e., the amount of structural bromine species as a percentage of the amount of butyl rubber monomer species.

In the invention, the normal vulcanization time t90 of the high-primary-position bromobutyl rubber is preferably 8-9.5 min, more preferably 8.3-9.2 min, and more preferably 8.6-8.9 min.

In the invention, the high-primary-position bromobutyl rubber preferably comprises the following raw materials in parts by mass:

in the present invention, the addition amount of the brominated butyl rubber cement is preferably 100 parts by weight.

In the present invention, the first structure stabilizer is preferably added in an amount of 2.0 to 2.6 parts by weight, more preferably 2.1 to 2.5 parts by weight, and still more preferably 2.2 to 2.4 parts by weight.

In the present invention, the first structure stabilizer preferably includes an alkali metal carboxylate and/or an alkaline earth metal carboxylate, more preferably an alkali metal carboxylate or an alkaline earth metal carboxylate.

In the present invention, the second structure stabilizer is preferably added in an amount of 1.0 to 1.5 parts by weight, more preferably 1.1 to 1.4 parts by weight, and still more preferably 1.2 to 1.3 parts by weight.

In the present invention, the second structure stabilizer preferably includes a polyethylene glycol-based compound.

In the present invention, the structural stabilizer preferably includes the first structural stabilizer and the second structural stabilizer, i.e., the first structural stabilizer and the second structural stabilizer are preferably collectively referred to as the structural stabilizer.

In the invention, the addition amount of the antioxidant is preferably 0.03-0.1 part by weight, more preferably 0.04-0.09 part by weight, more preferably 0.05-0.08 part by weight, and more preferably 0.06-0.07 part by weight.

In the present invention, the antioxidant preferably comprises an antioxidant commonly used in brominated butyl rubber raw materials.

The invention also provides a synthesis method of the high-primary-position bromobutyl rubber, which comprises the following steps:

1) mixing the butyl rubber organic solution with water to obtain a mixed glue solution;

2) mixing the mixed glue solution obtained in the step with the liquid bromine organic solution again, and carrying out bromination reaction under the condition of no light;

3) adding an alkaline solution into the reaction system in the step for pre-neutralization, then adding the alkaline solution again, and neutralizing again to obtain a brominated butyl rubber glue solution;

4) and adding a structural stabilizer and an antioxidant into the brominated butyl rubber glue solution obtained in the step to obtain the high-primary brominated butyl rubber.

The invention firstly mixes the butyl rubber organic solution and water to obtain the mixed glue solution.

In the present invention, the mass concentration of the butyl rubber organic solution is preferably 10% to 25%, more preferably 13% to 22%, and still more preferably 16% to 19%.

In the present invention, the organic solvent in the organic solution of butyl rubber preferably comprises a weakly polar and/or non-polar alkane solvent, more preferably a weakly polar or non-polar alkane solvent.

In the present invention, the mass fraction of the water in the butyl rubber organic solution is preferably 0.1% to 10%, more preferably 0.3% to 5%, and still more preferably 0.5% to 1%.

In the present invention, the organic solvent in the organic solution of butyl rubber preferably includes n-hexane and/or isohexane, more preferably n-hexane or isohexane.

In the present invention, one or more of inorganic peroxide, high-valent chlorine salt and high-valent bromine salt is preferably added to the raw material of the step 1), and inorganic peroxide, high-valent chlorine salt or high-valent bromine salt is more preferably added.

In the invention, the molar ratio of one or more of the inorganic peroxide, the high-valent chlorine salt and the high-valent bromine salt to the liquid bromine is preferably (0.05-2): 1, more preferably (0.4 to 1.6): 1, more preferably (0.8 to 1.2): 1.

in the present invention, the addition manner of one or more of the inorganic peroxide, the higher chlorine salt and the higher bromine salt preferably includes a manner of forming an aqueous solution with water.

In the present invention, the inorganic peroxide preferably includes hydrogen peroxide.

In the present invention, the higher chlorine salt preferably includes sodium hypochlorite.

In the present invention, the higher bromine salt preferably includes sodium bromate.

The invention mixes the mixed glue solution obtained in the above step and the liquid bromine organic solution again, and then carries out bromination reaction under the condition of no light.

In the present invention, the liquid bromine organic solution preferably comprises a liquid bromine alkane solution.

In the present invention, the liquid bromoalkane solution requires a light-shielding treatment.

In the present invention, the molar ratio of the liquid bromine to the isoprene units in the butyl rubber is preferably (0.4 to 1.0): 1, more preferably (0.5 to 0.9): 1, more preferably (0.6 to 0.8): 1.

in the invention, the time of the bromination reaction is preferably 5-20 min, more preferably 8-17 min, and more preferably 11-14 min.

In the invention, the temperature of the bromination reaction is preferably 20-60 ℃, more preferably 25-55 ℃, more preferably 30-50 ℃, and more preferably 35-45 ℃.

In the present invention, the mode of the bromination reaction preferably includes stirring to carry out the reaction.

Adding an alkaline solution into the reaction system of the step for pre-neutralization, then adding the alkaline solution again, and neutralizing again to obtain the brominated butyl rubber glue solution.

In the present invention, the basic solution preferably includes one or more of a hydroxide solution of an alkali metal, a hydroxide solution of an alkaline earth metal, and a strongly basic weakly acidic salt solution, and more preferably includes a hydroxide solution of an alkali metal, a hydroxide solution of an alkaline earth metal, or a strongly basic weakly acidic salt solution.

In the present invention, the alkaline solution preferably includes a sodium hydroxide solution and/or a sodium carbonate solution, more preferably a sodium hydroxide solution or a sodium carbonate solution.

In the present invention, the mass concentration of the alkaline solution is preferably 0.5% to 5%, more preferably 1% to 4.5%, more preferably 1.5% to 4%, more preferably 2% to 3.5%, more preferably 2.5% to 3%.

In the invention, the time for pre-neutralization is preferably 0.1-5 min, more preferably 1-4 min and 2-3 min.

In the present invention, in the pre-neutralization step, the mass ratio of the added alkaline solution to the total alkaline solution is preferably 5% to 95%, more preferably 25% to 75%, and still more preferably 45% to 55%.

In the invention, in the pre-neutralization step, the ratio of the molar weight of the solute in the alkaline solution to the molar weight of the bromine is preferably (1-90): 100, more preferably (20 to 70): 100, more preferably (40 to 50): 100. it is to be noted that, in the present invention, the sum of the alkaline solution added in the preliminary neutralization step and the alkaline solution added in the secondary neutralization step is referred to as a total alkaline solution.

In the present invention, the mass ratio of the mass of the alkaline solution added for the pre-neutralization to the total alkaline solution is preferably in positive correlation with the amount of the liquid bromine. I.e. they have a positive correlation, and when the amount of liquid bromine is increased, the mass ratio of the alkaline solution added for pre-neutralization to the total alkaline solution is increased.

In the invention, the percentage of the amount of the alkaline solution (calculated by sodium hydroxide) added in the pre-neutralization to the amount of the bromine simple substance is preferably (1-90): 100, more preferably (10 to 80): 100, more preferably (30 to 70): 100, more preferably (40 to 60): 100. the system is strongly acidic during pre-neutralization and has a small amount of bromine simple substance residues. After pre-neutralization, the speed of the water phase-organic phase separation is high, the organic phase bromine salt can be removed to a greater extent, and the cleanness of the product is ensured.

In the invention, the pH value after the secondary neutralization is preferably 6.5-8.0, more preferably 6.8-7.7, and more preferably 7.1-7.4.

In the invention, the time for the secondary neutralization is preferably 0.5-3 min, more preferably 1-2.5 min, and still more preferably 1.5-2 min.

According to the invention, the high-primary-position bromobutyl rubber is obtained by adding a structural stabilizer and an antioxidant into the bromobutyl rubber glue solution obtained in the step.

In the present invention, the structural stabilizer preferably includes a first structural stabilizer and a second structural stabilizer.

In the present invention, the first structure stabilizer preferably includes an alkali metal carboxylate and/or an alkaline earth metal carboxylate, more preferably an alkali metal carboxylate or an alkaline earth metal carboxylate.

In the present invention, the second structure stabilizer preferably includes a polyethylene glycol-based compound.

In the present invention, the antioxidant preferably comprises an antioxidant commonly used in brominated butyl rubber raw materials.

The invention is a complete and refined integral synthesis process, better ensures the structure and the characteristics of the high-primary-position bromobutyl rubber, improves the content of primary-position bromine, and the synthesis method of the high-primary-position bromobutyl rubber can specifically comprise the following steps:

the invention relates to a synthesis method for synthesizing high-primary-position bromobutyl rubber by a solution method by taking weak polar or nonpolar alkane as a solvent, which preferably comprises the following steps:

a. dissolving butyl rubber by using weak polar or non-polar alkane, adding a certain mass of inorganic peroxide or high-valent chloride (bromine salt) solution after fully dissolving, and fully mixing;

b. mixing the mixed glue solution with the liquid bromoalkane solution, and fully stirring;

c. adding an alkaline solution into a bromination system until the pH value of the system is 6.5-8.0, and stopping the reaction;

d. adding a certain proportion of auxiliary agents such as a structural stabilizer, an antioxidant and the like into the glue solution, and removing the solvent.

The solvent is preferably a nonpolar or weakly polar alkane solution with a relatively low price, including but not limited to n-hexane, isohexane and the like, and the concentration of the butyl rubber is preferably 10-25%.

The molar ratio of the inorganic peroxide or the high-valent chlorine salt (bromine salt) to the bromine is about 0.05-2, the inorganic peroxide includes but is not limited to hydrogen peroxide, and the high-valent chlorine salt (bromine salt) includes but is not limited to sodium hypochlorite, sodium bromate and the like. One or more of inorganic peroxide, high-valence chloride and high-valence bromide is/are used as oxidant to oxidize the hydrogen bromide entering the water phase into bromine, and the bromination reaction is continued, so that the bromine utilization rate is improved.

The desalted water is water, and the water can be added in the form of oxidant aqueous solution or can be independently used as raw material to be added into the reaction system.

In the invention, the bromination reaction lasts for about 5-20 min, the bromination needs to be carried out under the conditions of light shielding and stirring, the bromination temperature is controlled at 20-60 ℃, and the bromination reaction is carried out in an organic phase, and the oxidation reaction of hydrogen bromide is carried out in a water phase, so that the stirring efficiency needs to be improved and the mass transfer needs to be enhanced.

After the reaction of the invention is finished, alkaline solution is added into the glue solution. The alkali solution is added to neutralize residual bromine and hydrogen bromide. Moreover, the invention particularly employs a two-step addition of the alkaline solution. Specifically, the brominated glue solution is pre-neutralized in a neutralization reaction kettle A, the mass ratio of the added alkali liquor to the total alkali liquor is preferably 5-95%, more preferably 20-80%, the pre-neutralization time is preferably more than 0.5min, more preferably more than 3min, and at this time, the glue solution contains a small amount of residual bromine and hydrobromic acid. The alkaline solution may be a hydroxide solution of an alkali metal or an alkaline earth metal, such as a sodium hydroxide solution, or a strong base weak acid salt solution, such as a sodium carbonate solution.

The pre-neutralized glue solution is re-neutralized in a neutralization reaction kettle B, the pH of the system is adjusted to 6.5-8.0, and the neutralization time is about 0.5-3 min.

And finally, adding an auxiliary agent into the neutralized glue solution, and removing the solvent to obtain the brominated butyl rubber.

Referring to fig. 1, fig. 1 is a nuclear magnetic spectrum comparison of high-primary brominated butyl rubber prepared by the invention and common butyl rubber.

Wherein, the upper curve is a nuclear magnetic spectrum of common brominated butyl rubber, and the lower curve is a nuclear magnetic spectrum of high-primary brominated butyl rubber.

The invention provides high-primary-position bromobutyl rubber and a synthesis method thereof, wherein the high-primary-position bromobutyl rubber synthesized by the solution method has a primary-position bromine structure, and the molar content of the primary-position bromine structure in the bromobutyl rubber accounts for about 30 percent of the total molar number of isoprene units in the bromobutyl rubber. The high-primary-position bromine brominated butyl rubber provided by the invention can effectively control the bromination structure of the brominated butyl rubber, and the higher primary-position bromine structure greatly improves the vulcanization rate and shortens the processing time of downstream products to a certain extent.

The invention uses weak polar or non-polar alkane as solvent to prepare brominated butyl rubber by solution method, mainly using¹H-NMR specifically analyzed the bromine content and microstructure of the brominated butyl rubber. The method comprises the steps of firstly adding an oxidant solution in a certain proportion into a butyl rubber solution, then mixing the butyl rubber solution with a liquid bromine alkane solution for bromination reaction, adding an alkaline solution after the reaction is finished to enable a system to be neutral or alkalescent, adding the alkaline solution by a two-step method, and finally carrying out aftertreatment to obtain the brominated butyl rubber with the primary bromine structure content of about 30 percent, wherein the bromine utilization rate reaches over 90 percent, and the brominated butyl rubber has higher vulcanization rate and has the performances of stretching, sealing and the like which meet the use requirements of industrial products such as automobile tubeless tires, medical rubber plugs and the like.

Compared with the existing similar reaction process, the method has the advantages that the oxidant with a certain proportion is added into the glue solution before bromination, the bromine utilization rate is improved, the production cost is greatly saved, the reaction condition is easier to realize, particularly, the water environment is easier to realize, the bromination time is more flexible, the industrial application is convenient, and the existing similar reaction process has the two difficulties that the bromination time is short, the bromine content is lower, and the reaction time is longer, and the rubber degradation is serious.

Experimental results show that Mooney degradation of the high-primary-position bromobutyl rubber synthesized by the method is about 2-3 (ML (1+8),125 ℃), the high-primary-position bromobutyl rubber is similar to common bromobutyl rubber, the primary-position bromine structure accounts for 20-30% of the total mole number of isoprene units in the bromobutyl rubber, the vulcanization rate T90 is about 8-9 min, and the product performance can meet the use requirements of products such as automobile tires, medical rubber plugs and the like.

For further illustration of the present invention, a high primary bromobutyl rubber and its synthesis method are described in detail below with reference to the following examples, but it should be understood that these examples are carried out on the premise of the technical solution of the present invention, and that the detailed embodiments and specific procedures are given only for further illustration of the features and advantages of the present invention, not for limitation of the claims of the present invention, and the scope of the present invention is not limited to the following examples.

Example 1

30g of 268 butyl rubber are dissolved in 170g of n-hexane. After the solution was sufficiently dissolved, 0.5g of 33% hydrogen peroxide and 1g of demineralized water were added to the solution, and 0.28ml of a bromine solution was dissolved in 10ml of hexane and sufficiently mixed with the solution at 50 ℃. After 15min of reaction in the dark, 14g of 1% sodium hydroxide solution was added and neutralized for five minutes. 7g of 1% sodium hydroxide solution is added into the system, and the reaction is continued for 3 min. Adding a structure stabilizer (calcium stearate, epoxidized soybean oil) and an antioxidant (1010) into the glue solution, and then removing the solvent, wherein the proportion of the primary bromine structure of the obtained product is about 20%, the content of functional bromine is about 0.9-1.0%, and the vulcanization time T90 is about 8.5-9 min.

Example 2

30g of 268 butyl rubber are dissolved in 170g of n-hexane. After the solution was sufficiently dissolved, 2g of demineralized water was added to the gum solution, 0.40ml of the bromine solution was dissolved in 10ml of hexane, and the resulting solution was sufficiently mixed with the gum solution at 50 ℃. After 9min of reaction in the dark, 20g of 1% sodium hydroxide solution was added and neutralized for five minutes. 20g of 1% sodium hydroxide solution is added into the system, and the reaction is continued for 3 min. Adding a structure stabilizer (calcium stearate, epoxidized soybean oil) and an antioxidant (1010) into the glue solution, and then removing the solvent, wherein the proportion of the primary bromine structure of the obtained product is about 25%, the content of functional bromine is about 0.9-1.0%, and the vulcanization time T90 is about 8.3-8.8 min.

Comparative example 1

30g of 268 butyl rubber are dissolved in 170g of n-hexane. After the solution was sufficiently dissolved, 2g of demineralized water was added to the gum solution, 0.40ml of the bromine solution was dissolved in 10ml of hexane, and the resulting solution was sufficiently mixed with the gum solution at 40 ℃. After 9min of reaction in the dark, 40g of 1% sodium hydroxide solution was added and neutralized for five minutes. Adding a structure stabilizer (calcium stearate, epoxidized soybean oil) and an antioxidant (1010) into the glue solution, and then removing the solvent, wherein the proportion of the primary bromine structure of the obtained product is about 10%, the content of functional bromine is about 0.9-1.0%, and the vulcanization time T90 is about 9.2-9.8 min.

The above detailed description of a highly primary bromobutyl rubber and the method of synthesizing the same provided by the present invention, and the principles and embodiments of the present invention are described herein using specific examples, which are provided to facilitate an understanding of the method and its core concepts of the present invention, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.