Effect Of Catalyst Species On Phenol Content Of Phenolic Resin And Formaldehyde Content Of Phenolic Resin

Because of excellent insulation performance of phenolic resin, it is gradually be applied to the wall thermal insulation material, etc. But phenolic resin of the current industrial production is strong acid, phenol, aldehyde content of products is more, it is damage to the environment and harmful to human body. This paper mainly studies that effect of catalyst on p H value and phenol and formaldehyde content of phenolic resin.This experiment in the under condition of phenol and aldehyde ratio, temperature and pressure unchanged, using phenol and paraformaldehyde as raw materials, with sodium hydroxide, barium hydroxide, ammonia, zinc oxide, hydrochloric acid and oxalic acid as the catalyst, discusses the effect of the acidity and alkalinity of catalyst and catalyst dosage on viscosity, solid content, acidity and alkalinity of prepolymer, free phenol and free aldehyde of phenolic resin, mechanical properties and structure of the resin. Studies have shown that: With the increase of catalyst dosage, solid content and viscosity of phenolic resin prepolymer, tensile strength and impact strength of phenolic resin products are gradually enlarged, phenol and formaldehyde content of phenolic resin products are gradually reduced; When using sodium hydroxide, barium hydroxide, ammonia as the catalyst, synthesis the phenolic resin is thermosetting, formaldehyde content differences of phenolic resin products is very big; formaldehyde content respectively was 0.29%, 0.58%, 0.87%, 2%, formaldehyde mainly addition on ortho-position and para-position of phenol; When using Zinc oxide as catalyst, formaldehyde mainly addition on the ortho position of phenol, forming high ortho thermosetting phenolic resin; When using hydrochloric acid and oxalic acid as a catalyst, synthesis the phenolic resin is thermoplastic, the addition degree of formaldehyde on ortho-position of phenol is different with different acidity; When sodium hydroxide dosage of 3.5%, the solid-content of prepolymer is 86%, viscosity of prepolymer is 3.0Pa.s, the phenol content of products is 4.0%, the aldehyde of products is 4.0%, p H value of products is 14.0 and is strong alkaline, but when using ammonia as catalyst preparation of resin’s p H value is 7.41 and relatively well; When oxalic acid dosage of 1.5%, viscosity of prepolymer is 0.75 Pa.s, the solid-content of prepoiymer is 78%, the phenol of phenolic resin products is 8%, the aldehyde content of phenolic resin products is 0.04%, p H value of phenolic resin products is 3.55 and close to neutral. So when using ammonia and oxalic acid as the catalyst, prepared phenolic resin’s overall performance are optimal.