Like most other polymer materials, polyurethane is not heat-resistant, can be easily ignited, produces toxic gases, and endangers personal and property safety. Therefore, various methods are generally used to make polyurethane products have certain flame retardancy. Adding flame retardants is the most commonly used method. Flame retardants are important additives for polyurethane materials.

First, halogenated phosphate

Halogenated phosphoric acid ester compounds are a large class of additive organic flame retardants which are widely used in polyurethane foams and have significant effects. Most halogenated phosphates are liquid at room temperature, easy to use, have good compatibility with polyols, and are affordable. There are many types of halogenated phosphate flame retardants, and we will introduce the commonly used ones.

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 rigid foam. However, it is more effective for rigid foam because the closed cell ratio of rigid foam is low, the air permeability is small, the flame retardant is difficult to evaporate, and the flame retardant effect is maintained for a long time. Its disadvantage is that the amount is large. If the amount exceeds 15%, the physical properties of the foam will decrease.

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

TCEP is the earliest, most widely used and cheapest flame retardant. It has good hydrolysis resistance and high flame retardant efficiency, but it is easy to volatilize and lose flame retardance.

Manufacturers: Antiblaze100, Clariant, 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 it contains both phosphorus and chlorine in the molecule, it has significant flame retardancy, and also has plasticizing, moisture-proof, and antistatic functions. Because the phosphorus and chlorine content is lower than TCEP, its flame retardant effect is also relatively weakened.

TCPP is mainly used as a flame retardant for polyurethane foam. Generally used in rigid polyurethane foam and PIR rigid foam, also used in flexible polyurethane foam. It has poor durability when used for polyurethane soft foam, but it will not cause scorching of the foam.

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

Second, phosphate ester flame retardants

There are many types of phosphate esters, and many phosphate esters can be used as flame retardants for polyurethanes. But phosphate ester has plasticizing effect at the same time, it 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, which is characterized by high phosphorus content, excellent flame retardancy, low addition, low price, convenient use, and reduced Dual role of viscosity and flame retardant. In addition, the decomposition temperature of DMMP is greater than 187 ° C, so its thermal stability is better than that of halogen-containing flame retardants. It can be used for flexible and rigid polyurethane foams, and has a good flame retardant effect. Especially suitable for transparent or light-colored products and spraying applications. As an additive flame retardant for polyurethane foam, unsaturated polyester resin, and epoxy resins, the amount is generally in the range of 3% to 15%. However, DMMP is not suitable for pre- compounding in composites. It is recommended to add flame retardants before foam production.

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

2, ethyl diethyl 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 rigid foam formulations of various foaming systems. Its flame retardant efficiency is 1.5 to 2 times that of TCPP. DEEP has low viscosity and no halogen, and its chemical stability makes it very stable in the two-component system of polyether polyol and isocyanate. At the same time, it is a highly effective viscosity reducing agent, improving the operability of water-foamed rigid foams and polyester rigid foam systems. However, DEEP is not suitable for formulation in isocyanate components, such as prepolymers and one-component foams. Manufacturer: AntiblazeV490, Leveg-ardVPAC4048, DEEP, etc.