Preparation method of heat-resistant foamed microcapsule

Abstract

The invention provides a preparation method of a heat-resistant foamed microcapsule. The heat-resistant foamed microcapsule is prepared through suspension polymerization by taking an acrylonitrile monomer polymer as a cyst wall and taking a low-boiling-point alkane foaming agent as a core material. The method comprises the following steps of: (1) generating a main dispersing agent: adding silica sol into a reflowing and stirrinreaction kettle, and dripping an organic silicon coupling agent at a constant temperature for reacting to obtain a main dispersing agent; (2) generating a suspension emulsion: dispersing an aqueous mixed liquid and an oil-phase mixed liquid into small liquid drops under the action of a high-speed homogenizer to obtain a suspension emulsion; and (3) preparing a foamed microcapsule: transferring the suspension emulsion into a stirring reaction kettle, performing suspension polymerization at a constant temperature, reacting, naturally cooling to the room temperature, filtering, cleaning, drying and sieving to obtain a foamed microcapsule product. A product obtained with the preparation method implemented in the invention has the characteristics of high foaming rate, high heat resistance and uniform particle diameters, and can be applied in the fields of spinning, papermaking, ink, plastic, rubber and the like.

Description

technical field [0001] The invention relates to the technology of preparing foaming microcapsules by coating a physical foaming agent with a polymer shell, in particular to a preparation method of heat-resistant foaming microcapsules. The heat-resistant foaming microcapsules can be applied to the fields of textile, papermaking, printing ink, plastics, rubber and the like, where the foaming temperature is relatively high. Background technique [0002] Foaming microcapsules, also known as thermally expandable microcapsules, are microcapsules formed by wrapping a low-boiling point physical foaming agent with a thermoplastic polymer shell with good gas barrier properties. The foaming agent is formed by suspension polymerization. [0003] When the foaming microcapsules are heated, the blowing agent is vaporized, and an expansion force is generated to act on the polymer shell, reducing its modulus. When the temperature rises to a certain temperature, the capsules expand rapidly, ...

AI Technical Summary

Problems solved by technology

The Chinese invention patent with the patent number ZL02811733.6 titled "Thermal Foamable Microspheres and Its Manufacturing Method" proposes a technical solution for adding a silane coupling agent to the polymerization system after suspension polymerization for a certain period of time in the same polymerization system , which can reduce the adhesion of foamed particles and wide foaming behavior at lower temperatures; the main reason is that the added coupling agent is not uniformly dispersed in the suspension system, resulting in the phenomenon of gel groups in the crude product

The patent application number is 200680047764.X, and the Chinese invention patent application titled "Thermal Foamable Microspheres and Its Manufacturing Method and Application" proposes that the copolymerization scheme of methacrylonitrile and methacrylic acid is adopted, due to the formation of polymethacrylic acid The polymer shell with imide structure has a heat-resistant temperature above 220°C, but tests have found that this solution has the following two problems: (1) The polymer shell after foaming has little or no elasticity; 2) It cannot be miscible with alkaline substances (baking soda is usually added in shoe material processing), if it is miscible, it will shrink immediately after foaming

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