Thermal insulation phenolic foam production process
DATE：2021/12/23 8:32:03 / READ： / SOURCE：This station
Thermal insulation phenolic foam production process
(1) Raw materials and formula
① Phenolic resin. Phenolic resin is used as the main raw material, and the amount is about 50% to 90% of the total weight of the product. The selected resin is liquid at room temperature, so that it is easy to fill the mold during the foaming process, and it is also conducive to fully mixing with other components. According to the requirements of product performance and production process, the viscosity is usually 3000～5000Pa·s, and the moisture content is controlled at 6% to 8%. In order to prevent the occurrence of polycondensation and increase the viscosity, the general storage period is not more than three months, and it is stored under the condition of less than 20 ℃.
② Curing agent. Hydrochloric acid, sulfuric acid and their mixtures are generally used, but their curing effect is strong, the reaction is difficult to control during the foaming process, and the foam is easy to open. When the requirements are higher, benzene sulfonic acid, petroleum sulfonic acid and β naphthalene sulfonic acid are used as curing agents. In order to ensure uniform dispersion, solid organic sulfonic acid should be mixed into a high-concentration aqueous solution during use.
③Surfactant. It should have high emulsification performance and excellent foam stability to ensure that the components are mixed uniformly and the foam is stable during the foaming process. The best effect is a non-ionic surfactant. The more commonly used fatty alcohol polyoxyethylene polyoxypropylene ethers, alkylphenol polyoxyethylene ethers, polyoxyethylene polyoxypropylene block copolymers, not only have good foam Stable performance and strong emulsification.
④ Blowing agent. Generally, liquid foaming agent is used, which is easy to disperse in the resin during foaming. In the past, chlorofluorocarbons were most commonly used, but they would destroy the ozone layer of the atmosphere and were restricted. Among the chlorinated hydrocarbons, dichloromethane is the most commonly used, which has relatively stable chemical properties and higher gas emission than chlorofluorocarbons. In recent years, many manufacturers have used it instead of chlorofluorocarbons or both. The mixture of aliphatic alkanes C～C is often used in industry, which is cheap but flammable. Sometimes several foaming agents are used together
Solve the problem that the vaporization temperature of the blowing agent does not match the curing reaction speed of the resin. When the foaming agent vaporizes, the resin has an appropriate viscosity, which is beneficial to the formation and stability of the cell structure.
⑤ Other additives. According to product performance and production process requirements, modifiers, fillers, viscosity regulators and antistatic agents are sometimes added.
⑥ Formula. Table 8-14 is a typical formula of insulating phenolic foam with a density of 45kg/m23.
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