Paraformaldehyde (PF) is an industrially important linear formaldehyde polymer, also known as polymerized formaldehyde, paraformaldehyde, and solid formaldehyde. It appears as a white or colorless flammable crystalline powder or granular or flake solid. Paraformaldehyde is divided into two types: low polymerization degree paraformaldehyde and solid paraformaldehyde, but generally refers to low polymerization degree solid formaldehyde products, industrial products conventional powder with a CH2O content of greater than or equal to 95% and a CH2O content of 91 %-93% granular or powdery products for easy storage and transportation.

Paraformaldehyde is a high molecular polymer with the molecular formula (CH2O)n. It is a white amorphous powder with the smell of formaldehyde and is a linear polymer of formaldehyde. It has no fixed melting point and decomposes when heated. Melting point 120~170℃. It is easily soluble in hot water and releases formaldehyde, slowly soluble in cold water, soluble in caustic alkali and alkali metal carbonate solutions, insoluble in alcohol and ether, and its high polymer is insoluble in water. Reactions similar to formaldehyde can occur, such as chloromethylation, acetal formation with alcohols, etc.

Paraformaldehyde is mainly used in the production and use of herbicides, and is also used in the preparation of synthetic resins (such as artificial horn products or artificial ivory) and adhesives. Paraformaldehyde is used in the pharmaceutical industry (active ingredient in contraceptive creams) and pharmacies, clothing and bedding, etc. Paraformaldehyde can also be used as a fumigation disinfectant, bactericide and insecticide. Low polymerization degree paraformaldehyde replaces ordinary industrial formaldehyde aqueous solutions in various formaldehyde downstream products such as synthetic pesticides, synthetic resins, coatings, and the preparation of fumigation disinfectants. It can not only reduce the energy consumption of dehydration, but also greatly reduce wastewater treatment. This is a green and environmentally friendly project that benefits the country and the people. Paraformaldehyde with a low degree of polymerization has higher active ingredients than industrial formaldehyde and is a solid particle, which is beneficial to chemical synthesis and other industrial applications in chemical industry, pharmaceuticals, etc., especially in synthesis that requires the use of anhydrous formaldehyde as raw material, and has a wide range of uses. . It can also be used as a disinfectant, bactericide, fumigant and herbicide, as well as in the manufacture of resin and artificial ivory.