Like most other polymer materials, polyurethane is not heat-resistant, easily ignited, generates toxic gases, and endangers the safety of personal property. Therefore, polyurethane products are generally made flame retardant by various methods. Adding flame retardant is the most commonly used method. Flame retardant is an important additive for polyurethane materials.

　　1. Halophosphate

　　Halogenated phosphoric acid ester compound is a kind of added organic flame retardant which is widely used in polyurethane foam and has remarkable effect. Most halogenated phosphoric esters are liquid at room temperature, easy to use, have good compatibility with polyols, and are affordable. There are many varieties of halogenated phosphate flame retardants, and we will introduce the commonly used ones separately.

　　1 、 Tris (2-chloroethyl) phosphate

　　Tris (2-chloroethyl) phosphate (TCEP) is an additive flame retardant, which can be used in the production of polyurethane soft foam and hard foam. However, it is better for hard foam because of its high closed cell rate, low air permeability, difficulty in volatilization of flame retardant, and long-lasting flame retardant effect. Its disadvantage is that the dosage is large. If the dosage exceeds 15%, the physical properties of the foam plastic will decline.

　　TCEP is widely used in flame-retardant polyurethane foams. Adding 10% TCEP to polyurethane rigid or semi-rigid foam can obtain significant effects. The use of TCEP reduces the brittleness of hard foam without weakening the foam's corrosion resistance. When TCEP is used for flexible polyurethane foam, such as flame retardant modified high resilience foam, TCEP can be used in combination with melamine. TCEP can be injected directly into the mixing head as a separate component during the foaming process, or it can be mixed with polyether polyol before foaming, while reducing the viscosity of the polyol component.

　　TCEP is the earliest, the most widely used and the cheapest flame retardant. It has better hydrolysis resistance and higher flame retardant efficiency, but it is easy to volatilize and the flame retardancy is poor.

　　Manufacturers: Antiblaze100, Clariant Germany, Compton Group, Jiangdu Dajiang, Jiangsu Jacques, etc.

　　2. Tris (2-chloropropyl) phosphate

　　Tris (2-chloropropyl) phosphate (TCPP) is an additive flame retardant with good plasticizing effect. Because both phosphorus and chlorine elements are contained in the molecule, the flame retardant performance is remarkable, and it also has the functions of plasticization, moisture resistance, and antistatic. Because the phosphorus and chlorine content is lower than TCEP, its flame retardant effect is also relatively weakened.

　　TCPP is mainly used as flame retardant for polyurethane foam. Generally used in rigid polyurethane foam and PIR rigid foam, but also used in flexible polyurethane foam. When used in polyurethane soft foam, the durability is not good, but it will not cause the foam to scorch.

　　Manufacturers: American Yabao (AntiblazeTMCP and Antiblaze80), German Clariant, German Bayer (LevagardPP), Jiangdu Dajiang, Jiangsu Jacques, Zhangjiagang Changyu, etc.

　　Second, phosphate ester flame retardant

　　There are many varieties of phosphate esters, and many phosphate esters can be used as flame retardants for polyurethane. However, phosphate ester also has a plasticizing effect and is a plasticizer. When the amount is too large, it will soften the polyurethane and reduce the physical properties such as strength.

　　1. Dimethyl methyl phosphate

　　Dimethyl methyl phosphate (DMMP) is a halogen-free low-viscosity liquid additive flame retardant. It is characterized by high phosphorus content, excellent flame retardant performance, low additive amount, low price, easy to use, and reduced The dual function of viscosity and flame retardancy. In addition, the decomposition temperature of DMMP is greater than 187 ℃, so the thermal stability is better than halogen-containing flame retardants. It can be used for flexible and rigid polyurethane foams with good flame retardant effect. Especially suitable for the application of transparent or light-colored products and spraying. As an additive flame retardant for polyurethane foams, unsaturated polyester resins, and epoxy resins, the amount added is generally in the range of 3% to 15%. However, DMMP is not suitable for pre-mixing in the compound, it is recommended to add flame retardant before foam production.

　　Manufacturers: FyrolDMMP, AntiblazeDMMP, Lianmei　Qingdao,Shunchang Zhangjiagang, Qingdao Haida Chemical, etc.

　　2. Diethyl ethyl phosphate

　　Ethyl diethyl phosphate (DEEP) is a new type of highly efficient organic phosphorus flame retardant, which can be widely added to various rigid polyurethane foams, including hard foam formulations of various foaming systems. Its flame retardant efficiency is 1.5 to 2 times that of TCPP. DEEP has low viscosity and is halogen-free. Its chemical stability makes it very stable in polyether polyol and isocyanate two-component systems. At the same time, it is a high-efficiency viscosity-reducing agent and improves the operability of water-foamed rigid foam and polyester-based rigid foam systems. However, DEEP is not suitable for mixing in isocyanate components, such as prepolymers and single-component foams. Manufacturer: Antiblaze V490, Bayer (Leveg-ardVPAC4048, DEEP), etc.