Microencapsulation And Superfine Processing: What Are These New Flame Retardant Technologies About?

Microencapsulation and Superfine Processing: What Are These New Flame Retardant Technologies About?

Since the birth of self-extinguishing chlorinated rubber, using chemical methods to flame-retard polymers has a history of over a hundred years. In recent years, with increasing awareness of safety and environmental protection, flame retardancy requirements have received greater attention, leading to rapid development in flame retardant technologies and the continuous emergence of new techniques.

Below is a brief introduction to several new flame retardant technologies.

Microencapsulation Technology

The application of microencapsulation in flame retardants is a relatively new technology developed in recent years. The essence of microencapsulation involves crushing the flame retardant into fine particles, then coating them with organic or inorganic substances to form microcapsules with a diameter of 1–5000 μm, featuring semi-permeable or sealed membranes. Alternatively, flame retardants can be adsorbed into the pores of inorganic carriers with large surface areas, forming honeycomb-like microencapsulated flame retardants.

The shapes of microcapsules are diverse. They can be spherical like grape clusters or irregular in shape. The capsule surface can be smooth or folded. The capsule membrane can be single-layered, double-layered, or multi-layered. The core material enclosed by the membrane can be single-core or multi-core, as shown in the figure below.

Microencapsulation technology offers numerous advantages, such as preventing flame retardant migration, improving flame retardant efficiency, and enhancing thermal stability. It is also highly beneficial for component compounding and synergy, as well as for manufacturing multifunctional flame retardant materials.

Superfine Processing Technology

Inorganic flame retardants offer advantages such as high stability, low volatility, low smoke toxicity, and low cost. However, their poor compatibility with polymers and the large amounts required often reduce the mechanical and thermal properties of the material. Currently, the main research and development direction focuses on the superfine processing and nanonization of Aluminum Hydroxide (ATH).

Adding large amounts of ATH can reduce the mechanical properties of materials. However, filling with microfine ATH can instead produce a reinforcing effect similar to that of rigid particles, particularly with nanomaterials. Since the effectiveness of flame retardancy is governed by chemical reactions, for the same amount of flame retardant, smaller particle sizes result in larger surface areas and better flame retardant effects.

Furthermore, superfine nano ATH, due to enhanced interfacial interactions, can disperse more uniformly in the base resin, thereby more effectively improving the mechanical properties of the blend. Flame retardant polymers utilizing superfine technology combine the flexibility, low density, and easy processability of organic polymers with the strength, hardness, heat resistance, and dimensional stability of inorganic fillers, demonstrating strong vitality.

Macromolecular Technology

Current developments in flame retardant technology show many new trends. Macromolecular technology is one of the newly emerging technologies in flame retardant research. In recent years, research in this area has been very active and has yielded a series of achievements. For example, new developments in brominated flame retardants focus on increasing bromine content and molecular weight. It is well known that the main drawbacks of brominated flame retardants are their tendency to reduce the UV stability of the substrate and to generate more smoke, corrosive gases, and toxic gases during combustion, which limits their use to some extent. Macromolecular brominated flame retardants are significantly superior to many small molecule flame retardants in terms of migration resistance, compatibility, thermal stability, and flame retardancy, potentially making them the next generation of upgraded products.

Another example is phosphate ester compounds, which have high volatility and low heat resistance, requiring improvements in both their flame retardant performance and the mechanical properties of the compounded resin materials. Macromolecular flame retardants, such as polyaryl silico-diphosphates, not only exhibit excellent flame retardancy but also offer advantages like high thermal stability, low volatility, good compatibility with resins, no impact on processing performance, and durability, light resistance, and water resistance. Polymeric organophosphorus flame retardants have also become a key development focus, with a series of new high molecular weight or polymeric organophosphorus flame retardants featuring good compatibility and high stability having emerged successively.

Yinsu Flame Retardant has been dedicated to microencapsulated flame retardants for 21 years, covering the entire range from red phosphorus to phosphorus-nitrogen and organophosphorus systems. We use an "invisible armor" to address shortcomings in flame retardancy and upgrade physical properties, making every particle of flame retardant a tool for reducing costs and enhancing efficiency in our customers' formulations!