Process for polymerization preparation of macromolecular emulsion without heating

Abstract

The invention discloses a polymeric preparing method of macromolecular emulsion without heating, which comprises the following steps: acting 15-62 percent unsaturated olefin, 0.5-15 percent emulsifying agent, 0-8 percent pH adjustant and 82-33 percent water together at atmosphere temperature with oxidant and reducer; forming macromolecular emulsion through emulsion polymeric parttern. The invention improves the polymeric efficiency, which saves large amount of cool water.

Description

Technical field: [0001] The invention relates to a preparation method for polymer emulsion polymerization without heating or heating. Background technique: [0002] Emulsion polymerization is an important method for synthesizing polymers. There are three main methods: continuous method, semi-continuous method and batch method. The most commonly used method is the semi-continuous method, which is usually initiated by persulfate and polymerized at a temperature of 65 to 90 °C. The advantage of this polymerization is that the polymerization process is simple to control, the reaction can be kept relatively stable, and the quality is relatively stable. However, this process obviously has some disadvantages: in the dropwise addition process, the monomer concentration in the reaction system is always at a low level, and the reaction temperature is relatively high, which is not conducive to increasing the molecular weight of the polymer in terms of polymerization principle, and at ...

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Problems solved by technology

However, this technique obviously has some disadvantages: during the dropping process, the monomer concentration in the reaction system is always at a low level, and the reaction temperature is relatively high, which is not conducive to improving the molecular weight of the polymer from the principle of polymerization, and at the same time The continuous introduction of polymerization inhibitors (inhibitors, impurities, oxygen, etc. in the monomer) into the monomer emulsion that is added will also lead to a decrease in the molecular weight of the polymer.

Emulsion polymerization is usually the main industrial method for us to pursue high molecular weight polymers. In many applications, the molecular weight of polymers plays an important role in determining the properties of latex. Therefore, the performance of latex produced by semi-continuous method is limited to a certain extent.

At the same time, due to the use of ionic initiators, it is easy to produce some oligomers when the monomer concentration is very low. These oligomers generally have surface activity. many adverse effects

Another problem with the traditional emulsion polymerization process is that heating equipment is generally required, because the monomer emulsion polymerization of unsaturated olefins is usually initiated by free radical polymerization

Among them, the photolysis and radiation initiation of initiators can initiate emulsion polymerization at a very wide temperature, but because the polymerization process is too complicated, the equipment investment is too high, and the application is limited. At present, there are few successful industrial examples.

Initiator thermal decomposition is an important method of traditional emulsion polymerization. The disadvantage is that the decomposition temperature of the initiator is generally relatively high. For example, the commonly used persulfate triggers emulsion polymerization. If you want to observe an obvious polymerization process, the temperature should not be lower than 50 ° C. Obviously, even at such temperature, heating is unavoidable for the polymerization process, because the ambient temperature is usually below 30 °C

The redox decomposition of the initiator can initiate emulsion polymerization in a very wide temperature range. However, among the methods introduced by industry and patents, there are many methods whose initiation temperature has dropped to 30°C, which can meet the requirements of the ambient temperature. However, during the polymerization process Due to process design issues, heating is still required to complete the polymerization process

At the same time, when the ambient temperature is lower, or when the heat release of the polymerization system is relatively high, the method is limited, and a two-step method is required to obtain a polymer emulsion with a conventional solid content, which is obviously unfavorable for the synthesis of polymer emulsions.

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