Double-shell self-repairing microcapsule, and preparation method and application thereof

Abstract

The invention provides a double-shell self-repairing microcapsule, and a preparation method and application thereof. The double-shell microcapsule comprises a core material, a first wall material layer wrapping the core material and a second wall material layer wrapping the first wall material. The double-shell microcapsule provided by the invention is provided with two wall material layers, and thus has high mechanical strength; the double-shell microcapsule is a single-component repairing system, and after a coating is damaged, the microcapsule is broken to release isocyanate core material which reacts with moisture in air for curing so as to intelligently repair damage; and meanwhile, in a high-humidity environment, the isocyanate core material in the microcapsule can absorb moisture slowly permeating into the coating, so the waterproof performance of a coating material is enhanced.

Description

technical field [0001] The invention belongs to the technical field of coatings, and in particular relates to a double-shell layer self-repairing microcapsule and a preparation method and application thereof. Background technique [0002] Metal corrosion is a long-term problem that has plagued people, often involving very large economic costs and labor costs. According to the statistics of the American Society for Metals, the loss caused by corrosion in the United Kingdom in recent years has averaged 10 billion pounds, accounting for 3.5% of GDP; the loss in Germany is about 450 billion euros, accounting for 3.0% of GDP, and the annual corrosion loss in the United States is more than 300 billion US dollars, accounting for 4.2% of GDP. The loss in China is about 3-5% of GDP. In 2018, the total GDP of the country was 11.94 trillion US dollars. In other words, about 358.2-597 billion US dollars of metal was corroded, and about one third of it was corroded. It can be avoided by...

AI Technical Summary

Problems solved by technology

[0005] However, intrinsic self-healing materials can only repair some very fine scratches through the material's own elasticity or the interaction of chemical bonds. For large-area coating damage caused by scratches, it cannot be repaired. Heating or light is often required to trigger the repair effect. and other external force intervention, unable to adapt to complex and diverse use environments

However, the double-capsule repair system needs to prepare liquid resin repair base material and catalyst (curing) agent into microcapsules respectively. The materials of catalyst (curing) agent are often of various types, most of which are solid materials, and the process of preparing microcapsules is complicated. The cost is high, and the particle size of the two microcapsules is difficult to achieve uniformity. In addition, it is necessary to ensure that the two microcapsules are actually damaged, and the resin is released at the damaged site to repair the substrate and the catalyst to achieve the best reaction ratio to achieve a good repair effect.

[0006] In the synthesis process of traditional polyurethane / polyurea and polyurea-formaldehyde double-shell microcapsules, it is usually necessary to wash after the reaction to form the first layer of shell to remove the emulsifier and shell-forming agent in the reaction solution, so as to avoid contact with the next layer. The raw materials of the wall material have side reactions, but the microcapsules with only one layer of polyurethane / polyurea shell tend to have weak mechanical strength and are easily broken during cleaning, causing the microcapsules to stick together and affect the yield

Images