The Study Of Phenolic Resin Foam

Phenolic foam is a new type of thermal insulation material, and is of very broad application prospects for its light weight, heat insulation, fire-retardant and other advantages. At present the low-temperature method is used some extent in our country, the average temperature does not exceed 80℃, and the acid is adopted, so the product is of certain acidity. When contacting with metal the acid penetration can take place that brings metal erosion. In this paper, the high-temperature method is studied by experiment, where the foam forms and solidifies by heat, no acid is added, so the acid penetration and metal erosion do not take place.In the low-temperature method, the influence of curing agent, foaming agent, surfactant, foaming temperature, resin viscosity and solid content are studied. The conclusions are draw that with the increase of curing agent, curing time shortens, apparent density increases, compressive strength increases, and when the curing agent usage is 15%-20%, the foam is of better quality. With the increase in the amount of foaming agent, the apparent density and compressive strength of foam decrease. When the amount of foaming agent is more than 14%, the changes of the apparent density and compressive strength are not big. As the surfactant increasing, the apparent density increases in the beginning and then does not change, and the closed cell rate first increases and then reduces, the appropriate amount of surfactant is in 4%-10%. Higher foaming temperature is beneficial to getting good foam, but exorbitant high foaming temperature leads to perforation. The higher the viscosity and the solid content of the resin is, the easier to foam, and the better the apparent quality.In the high-temperature method, the influence of addition agent, surfactant, foaming temperature and resin viscosity are studied. Such conclusions are draw that the auxiliary agent will help to improve the apparent quality of the foam. When its usage is in 3-5%, the foam quality is better. The Influence trend of the Surfactant on the high-temperature foaming is same as on low-temperature foaming, but its usage in 4%-5% is advisable. With the increase of the resin viscosity, curing time shortens, apparent density first increases and then reduces. With the rising of the temperature, curing time shortens, apparent density reduces. The temperature generally is selected from 150℃to 180℃.The conclusions are got that for the high-temperature method, the compression strength is higher, closed cell ratio is lower, thermal conductivity is higher, thermal stability is higher, no acid infiltration and acid corrosion of metal take place, no big difference is observed in the flame-resistance between the two methods.Some dangerous and harmful factors from the two production process are discussed, such as chronic poisoning, skin burn from the acidic substances, explosion hazards from the volatile matter and the heat burn from the high-temperature. The method of the high-temperature has less danger than the low-temperature method.