文档介绍：Pu Synthetic Process
Pu Introduction
Pu Synthetic
Pu Variety Classification Applications
AND Applications
Pu Introduction
Pu whole called polyethylene carbamate, is contained in the molecular structure of the unit —NHCOO— the unit by high-pounds, and hydroxyl reaction system, reactive is as follows:
—N=C=O + HOˉ→—NH-COOˉ
In the 1970s, Germany to Bayer first synthesized PU. In 1950, PU as textile finishing agent in Europe, but mostly for solvent products used in dry coating. In the 1960s, due to the people environmental protection consciousness enhancement and the environmental protection laws and regulations, PU coating system. Since 1970's, PU PU fabric rapid development, has been widely used. Since the 1980s, the research and application of PU technical breakthrough progress appeared. Compared with the foreign and domestic textile finishing agent on PU study later.
Pu Synthetic
Pu by two phase position, including soft and hard and soft section is long chain polyols hard segment is by isocyanate and extender chain agent. Polyurethane is by isocyanate and polyols as by Mr Reaction, then with extender chain reaction. Sulfide agent, Sometimes use "one-step" for synthesis of polyurethane to reduce cost and increase the reaction speed. The so-called "one-step" will be polyols, isocyanate and extender chain reaction, step with polyurethane.
For synthesis of polyurethane, everyone knows that all the ingredients, pany easily absorbing polyether in shipping during drying, manufacturer can effectively use directly. During operation, so often accidental into water to degas. Small sample easily absorb a certain amount of moisture, therefore is synthesized in the lab before any isocyanate reaction should degas. Can be mixed gas off into the air. Below are adopted in the recipe or dry degas.
Terathane can be soft material and general diisocyanate reaction, global monly diisocyanate as 454 '- ErBenJi methane diisocyanate (MDI) and toluene diisocyanate (TDI), (2,4-difloo