Abstract: Provided is a modified blowing agent, wherein the surface of a blowing agent powder is coated with a metallic siloxylated compound. When the modified blowing agent is included in a polymer resin, dispersibility of the modified blowing agent is excellent in the polymer resin and fluidity of the polymer resin is improved in an extrusion molding machine and an injection molding machine, and thus productivity and processability can be improved. In addition, the foam that is formed using the polymer resin composition including the modified blowing agent has excellent tear strength, durability, and masking sound properties due to fine and uniform size of foam cells and increased number of foam cells per unit surface area.

Abstract: Provided are methods and devices for preparing biuret and cyanuric acid by thermal decomposition of urea. Specifically, a product of thermal decomposition is cooled to precipitate a crystal and the precipitated crystal is dissolved using an alkali aqueous solution and cooled to obtain biuret having high purity. Furthermore, the cyanuric acid that is one of byproducts by the thermal decomposition of urea is effectively recovered with high purity.

Abstract: The method for preparing hydrazodicarbonamide (HDCA) using biuret as a starting material is disclosed. The method comprises the steps of; obtaining metal monohalobiuret salt by reacting a biuret with a metal hypohalogen compound, or by reacting the biuret with a halogenating agent and a base; and reacting the obtained metal monohalobiuret salt with ammonia, wherein the hydrazodicarbonamide is produced in the presence of a catalyst including bromine or iodine atom and generating bromine or iodine ion during the reaction.

Abstract: The present invention relates to a method and apparatus for preparing hydrazodicarbonamide using urea as starting material economically and environmentally desirably. The apparatus includes a pyrolysis furnace to obtain biuret and ammonia by pyrolyzing urea; a recrystallization reactor to purify the biuret obtained from the pyrolysis furnace; a first reactor to obtain an metal monohalobiuret salt by reacting the biuret with metal hypohalogen compound or with halogen and base; a second reactor to synthesize the hydrazodicarbonamide by reacting the monohalobiuret metal salt with ammonia; and an ammonia evaporator to separate the excess ammonia from hydrazodicarbonamide and to supply the separated ammonia to an ammonia concentrator.

Abstract: A method for synthesizing hydrazodicarbonamide (HDCA) by a reaction of monohalobiuret metal salt having the formula 1 or 2, which is derived from biuret, and ammonia, wherein M is a metal and X is a halogen. The monohalobiuret metal salt is inexpensive and easy to synthesize and thus a great yield of HDCA can be obtained from the monohalobiuret metal salt at low cost.