Stable formaldehyde-free photosensitive microcapsule and preparation method thereof

Abstract

The invention relates to a stable formaldehyde-free photosensitive microcapsule and a preparation method thereof. The formaldehyde-free photosensitive microcapsule is composed of a capsule wall and a capsule core, the capsule wall material is a wall material, and a polysiloxane modified polyurea-polyurethane copolymer is used. The capsule core material is a core material and uses a photochromic high polymer material or a photochromic polymer, an epoxy resin copolymer, an ultraviolet absorbent and an inert diluent. The invention further provides a preparation method of the stable formaldehyde-free photosensitive microcapsule, the preparation method is simple and easy to operate, the prepared stable formaldehyde-free photosensitive microcapsule is good in light transmission, good in color development effect and excellent in mechanical property, the integrity of a microcapsule body can be guaranteed under the impact of external force, meanwhile, the stable formaldehyde-free photosensitive microcapsule also has good thermal stability, deformation, adhesion and leakage are avoided in a high-temperature environment, and good color changing performance is still achieved after long-time ultraviolet irradiation and repeated color changing.

Description

technical field [0001] The invention belongs to the technical field of polymer materials, and in particular relates to a stable formaldehyde-free photosensitive microcapsule containing a photosensitive color-changing material and a preparation method thereof. Background technique [0002] Photochromism refers to the reversible transformation process of certain chemical substances between two states with different colors after being excited by light. For example: the photochromic reaction of azobenzenes, fulgid anhydrides, spiropyrans, spirooxazines, diarylethenes and several new organic photochromic materials, wherein the diarylethene system has It is one of the most promising photochromic systems currently due to its extremely high thermal stability, excellent fatigue resistance, and significant differences in physical and chemical properties between different isomer states. Photochromic materials belong to photosensitive materials in the field of new materials, and are ma...

AI Technical Summary

Problems solved by technology

Since photosensitive microcapsules are often used in surface coatings and electronic equipment, the scratch resistance, extrusion performance and temperature resistance of the wall material are particularly important. When preparing traditional photosensitive microcapsules, melamine-formaldehyde resin and urea-formaldehyde resin are usually selected. As a wall material, although this type of low-cost resin can provide excellent mechanical properties to protect the microcapsules from rupture and failure due to external factors, it will produce a large amount of aldehydes that are harmful to health, and will rapidly age and decompose in an environment exceeding 150 °C And then lose the original function; while the core material simply melts and disperses the photochromic material into the inert diluent, once the wall material is damaged and broken, the photochromic material will be lost quickly, and the microcapsules will lose their effect

[0005] Chinese patent CN109876743A application discloses a photosensitive microcapsule containing a photosensitive color-changing material and its preparation method and application. The photosensitive microcapsule selects acrylate monomer or acrylate epoxy resin to synthesize polyacrylate or epoxy resin capsule wall. Although these substances can provide good mechanical properties at room temperature, their glass transition temperature (Tg) is low. When the temperature exceeds 120 °C, the capsule wall will rapidly soften and adhere to even rupture, which reduces the protection ability at high temperature. Difficult to apply to electronic equipment that needs to be exposed to high temperature for a long time

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