What is microencapsulation technology?

Microencapsulation is a technology that encapsulates trace substances in a polymer film, a miniature packaging technology for storing solids, liquids, and gases.

Specifically, it refers to completely encapsulating a target substance (core or inner phase) with a continuous thin film (wall or outer phase) of various natural or synthetic polymer compounds, without damaging the original chemical properties of the target substance. Then, gradually, through certain external stimuli or sustained-release effects, the function of the target substance is presented externally again, or the protective effect of the core material is achieved by the shielding effect of the capsule wall. The diameter of microcapsules is generally 1~500μm, and the thickness of the wall is 0.5~150μm. Ultra-microcapsules with a particle size of less than 1μm have been developed. In some instances, microcapsule particles are enlarged to 0.25～1000μm. When the particle size of microcapsules is less than 5μm, it is not easy to collect due to the intensified Brownian motion; when the particle size is greater than 300μm, its surface friction coefficient will suddenly decrease and lose its microencapsulation effect. The general capsule membrane wall thickness is 1-30μm. Those used in cosmetics are mostly 32μm and 180μm. The ultra-thin wall microcapsule membrane wall thickness is 0.01μm. Abroad, microcapsules have been used in cover creams, moisturizers, lipsticks, eye shadows, perfumes, bath soaps, and powders, etc. Microcapsules can improve product stability and prevent interference between various components.

Uses

Microcapsule: refers to a miniature container or package with a polymer shell. Its size generally ranges from 5-200μm, and its shape varies depending on the raw materials and preparation methods. Microencapsulation: The process of preparing microcapsules is called microencapsulation. Microencapsulation technology: refers to the technology of embedding solids, liquids, or gases in tiny, sealed capsules, so that they are only released at a controlled rate under specific conditions. Among them, the embedded substance is called the core material, including fragrances, acidulants, sweeteners, pigments, lipids, vitamins, minerals, enzymes, microorganisms, gases, and various other feed additives. The substance that encapsulates the core material to achieve microcapsule formation is called the wall material.

Core material: Can be oil-soluble, water-soluble compounds or mixtures, and its state can be powder, solid, liquid, or gas. The types of encapsulable substances are extremely diverse, such as cross-linking agents, catalysts, chemical reactants, color developers, humectants, drugs, insecticides, mineral oils, aqueous solutions, dyes, pigments, detergents, foods, liquid crystals, solvents, gases, hydrophobic compounds, and inorganic colloids, etc.

Wall material: Natural polymers, semi-synthetic polymers, and synthetic polymer materials can be used as microcapsule encapsulating materials. Depending on the nature of the encapsulated substance (core material), oil-soluble core materials require water-soluble encapsulating materials, and water-soluble core materials require oil-soluble encapsulating materials. That is, the encapsulating material should not react with the core material and should not be miscible with the core material. The properties of the polymer encapsulating material itself are also factors to be considered when selecting the encapsulating material, such as permeability, stability, solubility, polymerizability, viscosity, electrical properties, hygroscopicity, and film-forming properties, etc.