阅读说明：本技术 一种具有抑制氧阻聚作用的端乙烯基橡胶的制备方法 (Preparation method of vinyl-terminated rubber with oxygen inhibition effect ) 是由 陈加立 王建斌 陈田安 解海华 于 2019-10-25 设计创作，主要内容包括：本发明涉及一种具有抑制氧阻聚作用的端乙烯基橡胶的制备方法,其制备过程如下：选用分子量在1500-4000的端羟基聚丁二烯液体橡胶,第一步将分子链两端的羟基与异氰酸酯反应得到异氰酸酯基封端的预聚物,第二步将得到的预聚物与含羟基的烯丙基醚反应合成了端乙烯基橡胶。本发明制备的端乙烯基橡胶主要特点在于分子链两端具有烯丙基醚结构,有显著改善自由基聚合过程中氧阻聚的优点,同时具有柔韧性。(The invention relates to a preparation method of vinyl-terminated rubber with an oxygen inhibition effect, which comprises the following preparation processes: hydroxyl-terminated polybutadiene liquid rubber with the molecular weight of 1500-4000 is selected, hydroxyl at two ends of a molecular chain is reacted with isocyanate to obtain a prepolymer terminated by isocyanate groups in the first step, and the obtained prepolymer is reacted with allyl ether containing hydroxyl groups in the second step to synthesize the vinyl-terminated rubber. The vinyl-terminated rubber prepared by the invention is mainly characterized in that the two ends of a molecular chain have allyl ether structures, has the advantage of remarkably improving oxygen inhibition in the free radical polymerization process, and has flexibility.)

1. A method for preparing a vinyl-terminated rubber having an effect of inhibiting oxygen polymerization, comprising:

adding a catalyst into hydroxyl-terminated polybutadiene liquid rubber, heating to 110 ℃, reacting for 1.5 hours under a vacuum-pumping condition, adding diisocyanate when the temperature is reduced to 70-75 ℃, and reacting for 2 hours under a vacuum-pumping condition at 70-75 ℃ to obtain an isocyanate-terminated polybutadiene polymer resin;

adding hydroxyl-containing allyl ether into the obtained isocyanate-terminated polybutadiene polymer resin, maintaining the temperature at 60-80 ℃, and reacting for 2-4 hours under a vacuum-pumping condition to obtain vinyl-terminated rubber;

the vinyl-terminated rubber is characterized in that the molecular formula is as follows:

wherein n is ₁=15-20, R general structural formula:

R ₁representing hexamethylene diisocyanate, toluene diisocyanate and isophorone diisocyanateOne kind of (1);

R ₂represents

2. The method for preparing the terminal vinyl rubber as claimed in claim 1, wherein the molecular weight of the hydroxyl-terminated polybutadiene liquid rubber is between 1500-.

3. The method for preparing the vinyl-terminated rubber according to claim 1, wherein the catalyst is one of an organotin catalyst and an organobismuth catalyst, and is used in an amount of 0.02 to 0.08 percent by mass of the hydroxyl-terminated polybutadiene liquid rubber.

4. The method of claim 1, wherein the molar ratio of the-OH functional group to the-NC 0 group in the second experiment is 1.00:1 to 1.05: 1.

5. The method for preparing a vinyl-terminated rubber according to claim 1, wherein the diisocyanate is one or a combination of hexamethylene diisocyanate, toluene diisocyanate and isophorone diisocyanate.

Technical Field

The invention relates to a preparation method of vinyl-terminated rubber with an oxygen inhibition effect, belonging to the field of organic synthesis.

Background

The UV light curing glue and the double-component acrylate structural glue are widely suitable for bonding glass, plastics or metal. The curing agent has the advantages of high curing speed, high strength and the like, can realize automatic production line, and is widely applied to industries such as electronic appliances and the like. However, both the UV light-cured glue and the two-component acrylate structural glue follow a free radical polymerization mechanism, so that the UV light-cured glue and the two-component acrylate structural glue are inevitably easily inhibited by oxygen molecules in air in practical application. Thus, incomplete curing, stickiness on the surface, and the like are likely to occur. In order to solve the above disadvantages, physical methods such as addition of high melting point sealing wax or addition of hydrogen donor such as mercaptan, borane or phosphite are currently used in the industry. However, the floating of the sealing wax is incomplete, which affects the performance of adhesive force, and the hydrogen donors such as mercaptan, borane or phosphite cannot achieve good effect in practical application.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation method of terminal vinyl rubber with the function of inhibiting oxygen polymerization. This generated peroxide decomposes to generate highly reactive radicals, which in turn initiates further polymerization of the double bond. The oxygen molecules play a role in promoting polymerization in the whole process, so that the characteristic of poor surface drying caused by oxygen molecule inhibition in the free radical curing process is obviously improved. Besides the advantages of solving poor surface drying, the flexibility of a curing system can be increased, and the cured product prepared by using the method has the advantages of low modulus, high reliability and the like. The technical scheme for solving the technical problems is as follows:

a preparation method of vinyl-terminated rubber with the function of inhibiting oxygen polymerization. The preparation method mainly comprises the following steps: hydroxyl-terminated polybutadiene liquid rubber with the molecular weight of 1500-4500 is selected as an initial raw material, and the vinyl-terminated rubber is synthesized by a two-step method. The structural general formula of the vinyl-terminated rubber is as follows:

wherein n is ₁=15-20, R general structural formula:

r1 represents one of hexamethylene diisocyanate, toluene diisocyanate and isophorone diisocyanate;

R ₂represents

At this time n ₂=1；R ₂Represents

At this time n ₂=2；R ₂Represents

At this time n ₂=3。

Furthermore, the vinyl-terminated rubber related to the invention is mainly characterized in that both ends of a molecular chain have allyl ether structures, and the vinyl-terminated rubber has the advantage of remarkably improving oxygen inhibition in the free radical polymerization process. Meanwhile, in order to optimize the flexibility of the vinyl-terminated rubber, the molecular weight of the hydroxyl-terminated polybutadiene liquid rubber is preferably between 1500-4000.

Further, the preparation process of the isocyanate-terminated polybutadiene polymer resin can be optimized as follows: adding catalyst into hydroxyl-terminated polybutadiene liquid rubber, heating to 110 ℃, and reacting for 1.5 hours under the condition of vacuum pumping. When the temperature is reduced to 70-75 ℃, diisocyanate is added, and the reaction is carried out for 2 hours under the condition of 70-75 ℃ by vacuum pumping, thus obtaining the polybutadiene polymer resin terminated by isocyanate.

And further controlling the reaction ratio of the isocyanate-terminated polybutadiene polymer resin: the molar ratio of the-NC 0 functional group to the-OH is 2.00:1 to 2.10: 1. The reaction ratio can ensure that the hydroxyl in the hydroxyl-terminated polybutadiene rubber is fully reacted.

The catalyst adopted in the first step reaction is selected from organic tin catalyst or organic bismuth catalyst, and the dosage of the catalyst is 0.02-0.08 percent of the mass of the hydroxyl-terminated polybutadiene liquid rubber. The catalyst adopted in the reaction process has the advantages that: the reaction degree is improved, and the reaction time is shortened. Ensuring that the allyl ether is fully grafted to the macromolecular butadiene rubber in the subsequent reaction.

The second step is that: adding hydroxyl-containing allyl ether into the obtained isocyanate-terminated polybutadiene polymer resin, and maintaining the temperature at 60-80 ℃. And (3) reacting for 2-4 hours under a vacuum-pumping condition to obtain the vinyl-terminated rubber.

Controlling the reaction ratio of the vinyl-terminated rubber: the molar ratio of the-OH functional group to the-NC 0 is 1.00:1 to 1.05: 1.

Still further the above reaction for preparing the terminal vinyl rubber can be optimized as follows: the molar ratio of the-OH functional group to the-NC 0 is 1.00:1 to 1.03: 1. The vacuum degree is less than or equal to-0.09 MPa, the temperature is 70-75 ℃, and the reaction time is 3 hours.

Detailed Description

The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.