The most important use of paraformaldehyde is as a source of formaldehyde groups in the production of many thermosetting resins, together with phenol, urea, melamine, resorcinol and other similar reagents. These resins are used as moulding powders; in the wood industry as glues for chipboard, plywood and furniture; as bonding resins for brakes, abrasives and foundry dyes; as finishing resins for paper and textiles; as driers and glossing agents for paints; as insulating varnishes for electrical parts.
Some typical formulations for the production of such resins starting from paraformaldehyde include dichloroethyl formal, methyl phenol, disinfectants, insecticides, pharmaceuticals such as vitamin A, embalming preparations, dyestuff and special plasticizers.
In addition, paraformaldehyde is used as a fungicide and bactericide in industries as varied as crude oil production, beet sugar refining, and warehousing.
Paraformaldehyde has widespread acceptance as an additive to stop fermentation of the starch on oil-well-drilling muds.
The sugar beet industry used it to minimize the growth of algae in its continuous diffusers. Hotels and motels in humid areas often use it, with or without added mothproofing agents, in small bags hung in closets to prevent the formation of mildew.