What are the flame-retardant materials for temperature control boxes?

They are widely used in various fields such as construction, electronics, transportation, and furniture, serving as an important defense line for ensuring safe production and living.

I. Inorganic Flame-Retardant Materials

Inorganic flame-retardant materials, with their advantages of being non-toxic, environmentally friendly, high-temperature resistant, and low cost, are currently the most widely used flame-retardant materials. The core mechanism involves absorbing heat to cool down and forming an isolation layer to block the spread of flames. They are mostly in powder form and are often added as additives to various substrates.

(1) Metal Hydroxides

This type of material is the mainstream in the field of inorganic flame-retardants. During combustion, it releases crystalline water to absorb heat and form metal oxides to form a dense isolation layer, blocking oxygen from reaching the combustible material. Common examples include aluminum hydroxide (ATH) and magnesium hydroxide (MDH): Aluminum hydroxide has a lower decomposition temperature and is suitable for low-temperature processing scenarios such as plastics, rubber, and coatings; Magnesium hydroxide has a higher decomposition temperature and better thermal resistance, suitable for use in high-temperature environments such as cables and flame-retardant fabrics, and has a better smoke suppression effect than aluminum hydroxide.

(2) Metal Oxides and Salts

They mainly rely on their own high-temperature resistance or the release of inert gases to inhibit combustion. Some can also work synergistically with other flame-retardants. For example, antimony oxide is a commonly used synergistic flame-retardant agent. Used alone, its flame-retardant effect is limited, but when combined with halogen-based flame-retardants, it can significantly improve the flame-retardant efficiency and is widely used in plastics and rubber products; Zinc borate also has flame-retardant, smoke-suppressing, and drip-reducing functions, can replace some antimony oxide, reduce environmental hazards, and is suitable for materials such as coatings, wood, and fabrics; Calcium carbonate and magnesium sulfate are often used as auxiliary flame-retardants, reducing the burning rate of the material and improving the mechanical properties of the substrate.

(3) Inorganic Fillers

These are made from natural minerals and dilute the concentration of combustible substances in the substrate through the filling process, forming a physical barrier to block the spread of flames. Common examples include talc powder, kaolin, and mica powder. These materials not only enhance the flame-retardant properties of the substrate but also increase its hardness and wear resistance, and are widely used in products such as plastics, ceramics, and building panels.

II. Organic Flame-Retardant Materials

Organic flame-retardant materials are mostly organic compounds. The flame-retardant mechanism is mainly gas-phase flame retardancy, releasing flame-retardant gases to inhibit the combustion chain reaction. Some can form a carbon layer to block the flames, and are divided into halogen-based and non-halogen-based categories. Among them, non-halogen-based organic flame-retardants have become a trend due to their environmental friendliness.

(1) Halogen-Based Organic Flame-Retardants

These materials have high flame-retardant efficiency, low addition amount, and good compatibility with the substrate. They were widely used in various polymer materials, but when burned, they release toxic and harmful gases (such as hydrogen chloride and hydrogen bromide), polluting the environment and harming human health. Currently, they have been restricted in use by many countries and are only used in a few special high-end scenarios. Common examples include tetrabromobisphenol A (TBBPA), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecane (HBCD), which are mainly used for flame-retardancy in plastics, cables, and electronic components.

(2) Non-Halogen-Based Organic Flame-Retardants

They were developed to replace halogen-based flame-retardants and have excellent environmental performance. When burned, they do not release toxic gases, are suitable for high-end and environmentally demanding scenarios, and are gradually expanding their application. Common types include:

1. Phosphorus-Based Organic Flame-Retardants: The core mechanism involves forming a carbon layer to isolate oxygen during combustion and releasing phosphoric acid, polyphosphoric acid, and other substances to inhibit the combustion chain reaction. Phosphoric acid esters are suitable for plastics, coatings, and adhesives; Polyphosphorammonium (APP) has high flame-retardant efficiency and low cost, is currently the mainstream product in the non-halogen flame-retardant field, and is widely used in wood, paper, plastics, and fabrics. 2. Nitrogen-based organic flame retardants: They release inert gases such as nitrogen and ammonia to dilute the oxygen concentration, and simultaneously undergo exothermic decomposition to inhibit combustion. These are environmentally friendly, non-toxic, and have good smoke suppression effects. Common examples include melamine, melamine cyanurate (MCA), urea-formaldehyde resin, etc. They are suitable for plastics, rubber, wood, cables, etc. They are often used in combination with phosphorus-based flame retardants to enhance the fire resistance.

III. High-molecular material flame retardants

These materials are based on high-molecular polymers and achieve flame retardant properties by adding flame retardants or grafting flame-retardant groups. They combine the mechanical properties of the base material with the flame-retardant characteristics, and are suitable for scenarios requiring material toughness and molding properties. They are divided into flame-retardant plastics, flame-retardant rubbers, and flame-retardant fabrics.

(1) Flame-retardant plastics

They are the most widely used category of high-molecular flame retardants, using general-purpose plastics and engineering plastics as the base material and modified with flame retardants. Common examples include flame-retardant polyethylene (PE), flame-retardant polypropylene (PP), flame-retardant ABS, and flame-retardant PVC: Flame-retardant PVC has certain inherent flame retardancy and does not require a large amount of flame retardants to be added, and is often used in building pipes and cable sheaths; Flame-retardant PP and PE are modified with inorganic or halogen-free organic flame retardants, suitable for electronic enclosures and automotive components; Flame-retardant ABS has both toughness and flame retardancy and is used for household appliances, electronic component enclosures.

(2) Flame-retardant rubber

They are made from natural rubber or synthetic rubber and modified with flame retardants (such as aluminum hydroxide, phosphate esters, nitrogen-based flame retardants). They balance the elasticity of rubber with flame retardancy and are mainly used in cables, tires, seals, and mining conveyor belts, especially suitable for fire-resistant requirements in high-temperature and humid environments.

(3) Flame-retardant fabrics

They are made by treating natural fabrics (cotton, hemp) or synthetic fabrics (polyester, nylon) with flame retardant treatment. They are divided into durable flame-retardant fabrics and disposable flame-retardant fabrics. Durable flame-retardant fabrics use grafting of flame-retardant groups to achieve a flame-retardant effect that can withstand multiple washes and are used in fire-resistant clothing, protective clothing, curtains, carpets, etc.; Disposable flame-retardant fabrics achieve flame retardancy through surface spraying of flame retardants and are cost-effective, used for temporary protective items, packaging materials, etc.

IV. Other special flame retardant materials

In addition to the above three categories, there are also some special flame retardant materials suitable for extreme scenarios, such as flame-retardant wood (modified by impregnating with flame retardants, used in buildings and furniture), flame-retardant coatings (applied to the surface of the base material to form a flame-retardant protective layer, used for building walls, steel structures), flame-retardant foams (including polyurethane flame-retardant foams and polystyrene flame-retardant foams, used for insulation, soundproofing, packaging, etc.).