摘要:
The present invention provides a process for producing polycarbonates in the presence of one or more alkali metal or alkaline-earth metal catalysts, and subsequently removing the catalyst residues by chelation, to yield a clear polycarbonate product that is free from catalyst residues, and is thus suitable for use as a binding material in the ceramics industry where residual amounts of catalysts in the binder are burdensome.
摘要:
Disclosed are derivatives of isophorone diamine exhibiting a synergistic relationship with other commonly employed chain extenders offering enhanced efficacy with regard to slowing of the polyurea elastomer cure profile, and processes employing their use. According to the invention, extensions of the gel-free and tack-free times are more readily achieved at lower loading levels for these chain extender blends than are afforded through the sole use of the individual molecules.
摘要:
A method for the preparation of &ggr;-hydroxy ethers from cyclic organic carbonates and active-hydrogen-containing compounds in one form includes the steps of contacting an active-hydrogen-containing compound and a cyclic organic carbonate compound containing a six-membered ring, and a catalyst, running the reaction at a suitable temperature, and isolating the &ggr;-hydroxy ether as a mixture that can be purified or used directly as produced in the reaction.
摘要:
A method of preparing hydroxyalkylcarbamates from six-membered cyclic carbonates. The method involves reacting a six-membered cyclic carbonate with anhydrous ammonia or aqueous ammonium hydroxide. The present invention also provides for hydroxyalkylcarbamates prepared from six-membered cyclic carbonates, and for coating compositions comprising hydroxyalkylcarbamates prepared according to the present invention.
摘要:
Provided herein are cross-linked super absorbing polymers made by reacting a copolymer having an esterifiable acid group with a cyclic alkylene carbonate. The resulting cross-linked materials have an increased ability to retain absorbed liquids even under the influence of applied stress. Catalysts are also disclosed which are useful in promoting the reaction between the alkylene carbonate and copolymer.
摘要:
A method of preparing hydroxyalkylcarbamates from six-membered cyclic carbonates. The method involves reacting a six-membered cyclic carbonate with anhydrous ammonia or aqueous ammonium hydroxide. The present invention also provides for hydroxyalkylcarbamates prepared from six-membered cyclic carbonates, and for coating compositions comprising hydroxyalkylcarbamates prepared according to the present invention.
摘要:
An improved method for preparing amino polyols is disclosed. The method is the Mannich condensation of phenol, formaldehyde and diethanolamine in a molar ratio of (1:1:1), and then alkoxylation with a mixture of ethylene oxide and propylene oxide in a weight ratio of about 5:95 to 20:80 to form an amino polyol of hydroxyl number 440 to 515.The method gives higher yields of aromatic amino polyols of lower viscosity than those of the comparative example.
摘要:
Polyol-catalyst mixtures, useful in the preparation of rigid polyurethane cellular products, are prepared simultaneously by reacting a Mannich base compound, water, and an epoxide and subsequently removing the water from the reaction mixture. Also provided are new rigid polyurethane cellular products having a high content of isocyanurate linkages, superior heat distortion temperatures and improved insulating properties, which products are obtained by reacting a polyisocyanate with the aforementioned polyol-catalyst mixture.
摘要:
The use of tertiary amino substituted oxazolidines as polyisocyanurate catalysts is disclosed. Said catalysts are useful in promoting the reaction between a polyol and an aromatic polyisocyanate to prepare a polymer containing recurring isocyanurate and urethane linkages.