阅读说明：本技术 一种羧基氯丁胶乳的制备方法 (Preparation method of carboxyl neoprene latex ) 是由 戴祖宏 曾维亮 于凯华 叶伟 于 2019-10-31 设计创作，主要内容包括：本发明涉及胶乳生产技术领域,公开了一种羧基氯丁胶乳的制备方法,步骤包括配制水相、配制油相、配制终止剂、聚合,其特征在于：所述配制油相包括以下步骤：油相一的配制,S1：使用氮气将氯丁二烯压送到油相配制槽I内,并对氯丁二烯搅拌；S2：将S1中的氯丁二烯加热至16～20℃；S3：向油相配制槽I内加入调丁,搅拌至少20min,待调丁溶解,完成油相一的配制；油相二的配制,S4：计量软水放入到油相配制槽II内且搅拌软水,搅拌软水的过程中加入NaOH；S5：向油相配制槽II内加入丙烯酸单体,完成油相二的配制。本方案,可以在聚合时,避免聚合单体发生自聚。(The invention relates to the technical field of latex production, and discloses a preparation method of carboxyl neoprene latex, which comprises the following steps of preparing a water phase, preparing an oil phase, preparing a terminator and polymerizing, and is characterized in that: the oil phase preparation comprises the following steps: preparation of oil phase one, S1: pressing chloroprene into the oil phase preparation tank I by using nitrogen, and stirring chlorobutadiene; s2: heating chloroprene in S1 to 16-20 ℃; s3: adding the blend blocks into the oil phase preparation tank I, stirring for at least 20min, and completing the preparation of the oil phase I after the blend blocks are dissolved; preparation of oil phase two, S4: adding measured soft water into the oil phase preparation tank II, stirring the soft water, and adding NaOH in the process of stirring the soft water; s5: and adding an acrylic acid monomer into the oil phase preparation tank II to finish the preparation of the oil phase II. According to the scheme, the self-polymerization of the polymerized monomer can be avoided during polymerization.)

1. The preparation method of carboxyl neoprene latex comprises the steps of preparing water phase, preparing oil phase, preparing terminator and polymerizing, and is characterized in that: the oil phase preparation comprises the following steps:

preparation of oil phase I

S1: pressing chloroprene into the oil phase preparation tank I by using nitrogen, and stirring chlorobutadiene;

s2: heating chloroprene in S1 to 16-20 ℃;

s3: adding the blend blocks into the oil phase preparation tank I, stirring for at least 20min, and completing the preparation of the oil phase I after the blend blocks are dissolved;

preparation of oil phase two

S4: adding measured soft water into the oil phase preparation tank II, stirring the soft water, and adding NaOH in the process of stirring the soft water;

s5: and adding an acrylic acid monomer into the oil phase preparation tank II to finish the preparation of the oil phase II.

2. The process for preparing a carboxylated polychloroprene latex according to claim 1, wherein: in S5, the temperature of the solution in the oil phase preparation tank II is heated to 30 +/-5 ℃.

3. The process for preparing a carboxylated polychloroprene latex according to claim 1, wherein: when preparing the aqueous phase, the method also comprises the preparation of an electrolyte solution, wherein the preparation of the electrolyte solution comprises the following steps: adding soft water into the preparation container, heating the soft water in the preparation container, adding sodium phosphate into the preparation container, and stirring to dissolve the sodium phosphate to complete the preparation of the electrolyte solution.

4. The process for the preparation of carboxylated polychloroprene latex according to claim 2, characterized in that: the temperature for preparing the electrolyte solution is 50-55 ℃.

5. The process for preparing a carboxylated polychloroprene latex according to claim 4, wherein: during polymerization, the first oil phase is first put into a polymerization kettle, the second oil phase is then put into the polymerization kettle, and the first oil phase and the second oil phase are stirred and mixed.

6. The process for preparing a carboxylated polychloroprene latex according to claim 1, wherein: the preparation of the water phase comprises the following steps: the method comprises the following steps: metering soft water, putting the soft water into a water phase preparation tank, and heating the soft water; step two: adding a polyoxyethylene ether emulsifier into the water phase preparation tank, stirring for at least 1h, then adding sodium petroleum sulfonate into the water phase preparation tank, and stirring for at least 1h until the solution in the water phase preparation tank is uniform, and the step three: and (5) cooling the solution in the water phase preparation tank to room temperature to finish the water phase semi-finished product.

7. The process for preparing a carboxylated polychloroprene latex according to claim 6, comprising the steps of: heating the soft water in the step one to 60-70 ℃.

8. The process for preparing a carboxylated polychloroprene latex according to claim 7, wherein: sampling and detecting the water phase semi-finished product to detect the density and the content of each component of the water phase semi-finished product.

9. The process for preparing a carboxylated polychloroprene latex according to claim 8, wherein: and (3) when polymerization is carried out, sending the water-phase semi-finished product obtained in the step three into a water-phase metering tank, introducing steam, and adding soft water to dilute the water-phase semi-finished product to finish preparation of the water-phase liquid.

10. The process for preparing a carboxylated polychloroprene latex according to claim 9, characterized in that: and (3) raising the temperature of the water-phase semi-finished product to 45-55 ℃ by introducing steam.

Technical Field

The invention relates to the technical field of latex production, in particular to a preparation method of carboxyl neoprene latex.

Background

The carboxyl neoprene latex is emulsion obtained by copolymerizing chloroprene and acrylic acid compounds, which is called XCRL for short. As the main chain is introduced with strong polarity-COOH, the material has a series of advantages of oil resistance, solvent resistance, aging resistance, particularly good storage stability, good adhesion, elasticity, film forming property, chemical resistance, non-flammability, non-explosion, safety, non-toxicity, no environmental pollution and no harm to health.

The advantages and disadvantages of the carboxyl chloroprene latex are generally determined by the stability of the carboxyl chloroprene latex, and in the prior art, the reactivity ratios of chloroprene and unsaturated acrylic monomers are greatly different, so that the self-polymerization phenomenon of comonomers is very easy to occur in the polymerization process, and therefore, the selection of the emulsion polymerization mode and the emulsifier type are the key points and difficulties of the chloroprene and the unsaturated acrylic monomers. The prior art adopts: the oil phase is averagely divided into 2 parts, a second monomer of unsaturated carboxylic acid is added into one part, then the mixture is mixed and emulsified with the water phase, then the polymerization reaction is initiated, then the other part of the oil phase is dripped to continue the reaction, and after the reaction is finished, a stabilizing agent is added to terminate the reaction, so that the polymerization operation is complex. Therefore, the applicant has studied a polymerization method of carboxyl chloroprene latex in order to reduce the operational difficulty.

Disclosure of Invention

The invention aims to provide a preparation method of carboxyl neoprene latex, which is used for reducing the difficulty of polymerization operation of the carboxyl neoprene latex.

In order to achieve the purpose, the invention provides the following technical scheme: the preparation method of carboxyl neoprene latex comprises the steps of preparing water phase, preparing oil phase, preparing terminator and polymerizing, and is characterized in that: the oil phase preparation comprises the following steps:

preparation of oil phase I

S1: pressing chloroprene into the oil phase preparation tank I by using nitrogen, and stirring chlorobutadiene;

s2: heating chloroprene in S1 to 16-20 ℃;

s3: adding the blend blocks into the oil phase preparation tank I, stirring for at least 20min, and completing the preparation of the oil phase I after the blend blocks are dissolved;

preparation of oil phase two

S4: adding measured soft water into the oil phase preparation tank II, stirring the soft water, and adding NaOH in the process of stirring the soft water;

s5: and adding an acrylic acid monomer into the oil phase preparation tank II to finish the preparation of the oil phase II.

The principle and the beneficial effects of the invention are as follows: the carboxyl chloroprene latex is mainly prepared by introducing strong polar-COOH groups on a chloroprene main chain in a copolymerization mode by taking an acrylic monomer as a second monomer and chloroprene. However, the reactivity ratio of chloroprene and unsaturated acrylic monomer is high, so that the self-polymerization phenomenon of comonomer is very easy to occur in the polymerization process, and the selection of emulsion polymerization mode and emulsifier type is the key point and difficulty of copolymerization of chloroprene and unsaturated acrylic monomer. In the prior art, during polymerization, an oil phase is averagely divided into 2 parts, a second monomer of unsaturated carboxylic acid is added into one part of the oil phase, the second monomer is mixed with a water phase and emulsified to initiate polymerization reaction, then the other part of the oil phase is dripped to continue reaction, a stabilizer is added after the reaction is finished to terminate the reaction, and during polymerization, the amount and time for adding the second part of the oil phase are difficult to master, so that the operation difficulty is increased.

According to the scheme, the oil phase I and the oil phase II are separately prepared, so that on one hand, the raw materials in the two oil phases can be fully dissolved, and on the other hand, the self-polymerization phenomenon of acrylic monomers can be prevented during polymerization, so that the acrylic monomers are all copolymerized. Secondly, before polymerization, the oil phase I and the oil phase II are added into a polymerization kettle together, so that the oil phase is not required to be added in the polymerization reaction process, and the difficulty of the polymerization operation of the carboxyl neoprene latex is reduced.

Further, in S5, the temperature of the solution in oil phase preparation tank II was heated to 30 ± 5 ℃.

Has the advantages that: at the temperature, NaOH and acrylic acid monomer are favorably mixed, a large amount of volatilization and self-polymerization of acrylic acid are avoided in the temperature range, and a refrigerant in the temperature range of 30 +/-5 ℃ is easier to select.

Further, when preparing the water phase, the method also comprises the step of preparing an electrolyte solution, wherein the step of preparing the electrolyte solution comprises the following steps: adding soft water into the preparation container, heating the soft water in the preparation container, adding sodium phosphate into the preparation container, and stirring to dissolve the sodium phosphate to complete the preparation of the electrolyte solution.

Has the advantages that: in the prior art, the electrolyte solution is added at the time of the preparation of the terminating agent, and the stability of the latex is adjusted only after the termination. The electrolyte solution is prepared in advance, the electrolyte solution is added when the water phase is added into the polymerization kettle, the electrolyte solution enters a polymerization system during emulsification, the pH of the emulsion can be adjusted in the whole polymerization process, and the stability of the chloroprene latex in the whole polymerization process and finally is ensured.

Further, the temperature for preparing the electrolyte solution is 50-55 ℃.

Has the advantages that: in this temperature range, sodium phosphate can be sufficiently dissolved in soft water.

Further, during polymerization, the oil phase I is firstly placed into a polymerization kettle, then the oil phase II is placed into the polymerization kettle, and the oil phase I and the oil phase II are stirred and mixed.

Has the advantages that: in the traditional technology, during polymerization, an oil phase is averagely divided into 2 parts, a second monomer of unsaturated carboxylic acid is added into one part, then the two parts are mixed and emulsified with a water phase, then polymerization reaction is initiated, the other part of the oil phase is dripped to continue reaction, and after the reaction is finished, a stabilizer is added to terminate the reaction, so that the polymerization operation is complex. The scheme is improved, and the oil phase I and the oil phase II are put into a polymerization kettle before polymerization, so that the oil phase is prevented from being added in the polymerization process, and the operation difficulty is reduced.

Further, the preparation of the aqueous phase comprises the following steps: the method comprises the following steps: metering soft water, putting the soft water into a water phase preparation tank, and heating the soft water; step two: adding a polyoxyethylene ether emulsifier into the water phase preparation tank, stirring for at least 1h, then adding sodium petroleum sulfonate into the water phase preparation tank, and stirring for at least 1h until the solution in the water phase preparation tank is uniform, and the step three: and (5) cooling the solution in the water phase preparation tank to room temperature to finish the water phase semi-finished product.

Has the advantages that: the traditional method for preparing the water phase is to directly prepare a finished product, and the scheme firstly prepares a semi-finished product of the water phase, and then heats up to prepare the water phase liquid when the semi-finished product needs to be polymerized for use, so that a stable emulsion is formed by using the solution, and the stability of the emulsion after the water phase liquid is prepared is prevented from being reduced.

Further, heating the soft water in the step one to 60-70 ℃.

Has the advantages that: the soft water temperature is in the range, which is beneficial to fully dissolving the polyoxyethylene ether emulsifier and the petroleum sodium sulfonate.

Further, sampling and detecting the water phase semi-finished product to detect the density and the content of each component of the water phase semi-finished product.

Has the advantages that: by measuring the density and the content of each component of the water phase semi-finished product, whether the addition of the polyoxyethylene ether emulsifier, the petroleum sodium sulfonate and the like is correct or not can be examined, and meanwhile, the volume measured by the water phase can be conveniently converted.

And further, when in polymerization, sending the water-phase semi-finished product obtained in the step three into a water-phase metering tank, introducing steam, and adding soft water to dilute the water-phase semi-finished product to finish the preparation of the water-phase liquid.

Has the advantages that: the emulsifying effect of the polyoxyethylene ether emulsifier is greatly influenced by the temperature, and the temperature rise is favorable for forming stable emulsion when in use.

Further, the temperature of the water phase semi-finished product is raised to 45-55 ℃ by the introduced steam.

Has the advantages that: the emulsifying effect of the polyoxyethylene ether emulsifier is more appropriate within the range of 45-55 ℃.

Detailed Description