| Phenolic resins in solution include two major categories, water-soluble andorganic solvent phenolic resins. The water-soluble phenolic resins are small molecularweight, poor stability, poor resistance to weather and miscibility with water to reducewith the time prolonging, which are various problems in practical applications.Phenolic resins are general soluble in organic solvents before cured, and people useorganic solvent dilution to reduce its viscosity can meet the needs of the storage anduse. The production process of the organic solvent phenolic resins is mature. But theorganic solvent phenolic resins which is not only higher production costs, easy toproduce toxic gas in the production and application, but also harmful to human healthand the environment, and there are some disadvantages including flammable, volatile,poor storage stability and so on. With the improvement of environmental awareness,the study of water-based phenolic resin system has attracted much attention. Withwater as solvent instead of organic solvent, which not only reduce the productioncosts, but also eliminates the environmental pollution caused by organic solvent.In this paper, the stable aqueous phenolic resin was synthesized via one-stepmethod. Then the aqueous phenolic resin dispersions were used to preparefire-retardant coatings and its flame-retardant property and water resitance werecharacterizated.1. The aqueous phenolic resin dispersions were prepared by one-step withhydroxyethyl cellulose (HEC) as protective colloid and sodium dodecyl-benzenesulfonate (SDBS) as emulsifier. the influences of the ratio of formaldehyde to phenol,amount of catalyst, reaction time, proportion of monomer to water, amount ofprotective colloid and the amount of emulsifier on the product stability, solid content,particle size and the content of free formaldehyde were discussed.2. Aqueous phenolic dispersions and melamine pyrophosphate (MPP) complexas a flame retardant, and the synergism between pheolic and melamine pyrophosphatewas discussed through TGA analysis and IR analysis on combustion residues. IRshowed that MPP and phenolic resin had generated ester at high temperatures. TGA showed that MPP mixed with phenolic resins had a better performance in thermalstability than they were used separately in the same test conditions, and the onsetdecomposition temperature decreased relative to phenolic resins, it was benefit to theflame retardant effect.3. The aqueous phenolic resin dispersions and MPP were used as a flameretardant to prepare fire-retardant coatings, the effects of quality ratio of MPP tophenolic resin and amount of silicone-acrylic emulsion to flame resistance, waterresistance and adhesive force were discussed. The coating obtained from the formulahas good comprehensive properties such as good water resistance and flame resistance. |
