High-temperature expanded polymer microspheres and preparation method thereof

Abstract

The invention provides high-temperature expanded polymer microspheres and a preparation method thereof and belongs to expandable particles. The high-temperature expanded polymer microspheres are prepared from a thermoplastic resin shell body and a foaming agent packaged in the shell body, wherein an oil-phase composition composed of a polymerizable monomer and a crosslinking agent can be dispersedinto a water-phase dispersed composition; in the presence of the foaming agent, the polymer microspheres coated with the foaming agent are directly prepared through carrying out suspension polymerization reaction and coating the foaming agent in situ; the high-temperature expanded polymer microspheres are characterized in that the oil-phase composition contains the polymerizable monomer and the crosslinking agent, and also comprises a silane coupling agent; the foaming agent is a mixture of isopentane, isooctane and n-octane; the high-temperature expanded polymer microspheres provided by theinvention have the advantages of complete core-shell structure, uniform grain diameter distribution, high foaming agent coating efficiency, good heat resistance of a shell-layer polymer, relatively high initial temperature in an expansion process, relatively high highest expansion temperature and high foaming ratio, have a relatively wide foam stabilizing temperature range, and are suitable for being applied to a thermoplastic resin, rubber or thermoplastic elastomer foaming and processing technology.

Description

technical field [0001] The invention relates to a high-temperature expanded polymer microsphere and a preparation method thereof. Belongs to expandable particles. Background technique [0002] Thermally expandable polymer microspheres are a multifunctional foaming material with a wide range of uses. It is an extremely small spherical particle with a shell-core structure. The core of the microsphere is liquid low-boiling alkanes, and the shell of the microsphere is a thermoplastic polymer with good airtightness that can prevent the substances in the core from escaping. At room temperature, the shell of the microsphere is hard and the particles are tiny. When heated, when the heating temperature is higher than the glass transition temperature of the shell, the shell material softens and the core material gasifies to generate internal pressure, causing the microspheres to expand. The volume increased significantly. The particle size of the microspheres before expansion is ...

AI Technical Summary

Problems solved by technology

[0008] However, in the prior art, the heat-expandable polymer microspheres prepared by the suspension polymerization method still have the following deficiencies, and it is difficult to obtain high-temperature expansion polymer microspheres:

[0009] 1. Uneven particle size distribution

[0010] 2. The thermoplastic resin shell polymer of heat-expandable polymer microspheres has poor heat resistance, which leads to yellowing and rupture of heat-expandable microspheres during resin foaming processing

[0011] 3. The core-structure is incomplete, and the coverage rate of the foaming agent is low

[0012] 5. The heat resistance of the product is not good enough

[0013] 6. The expansion ratio is low, and the temperature range of foam stabilization is not wide enough

[0014] 7. The suspension polymerization reaction time in the prior art is as long as 20 hours, resulting in uneven particle size distribution of the product and low foaming agent coating rate

and increased production costs

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