摘要:
The present invention provides polyurethane foams and elastomers made with an alkoxylated vegetable oil hydroxylate replacing at least a portion of the typically used petroleum-based polyol(s). Also provided are processes for making the inventive foams and elastomers and for making alkoxylated vegetable oil hydroxylates. The alkoxylated vegetable oil hydroxylates are environmentally-friendly, bio-based polyols which advantageously also offer the potential of improved hydrophobicity in polyurethane foams and elastomers. The inventive polyurethane foams and elastomers may find use in a wide variety of products such as automobile interior parts, polyurethane structural foams, floor coatings and athletic running tracks.
摘要:
Double metal cyanide-catalyzed polyols are made by an improved process in which a starter is continuously added during polymerization of the epoxide. The process includes a continuously added starter (S.sub.c), and optionally, an initially charged starter (S.sub.i). The continuously added starter comprises at least about 2 equivalent percent of the total starter used. The process enables the use of water and low molecular weight polyol starters in DMC-catalyzed polyol synthesis. In addition, the process gives polyether polyols having reduced levels of high molecular weight polyol tail, which can adversely affect polyurethane foam processing.
摘要:
A continuous process for the preparation of polyoxyalkylene polyethers using DMC catalysts as the polyoxyalkylation catalyst employs continuous addition of alkylene oxide in conjunction with continuous addition of starter and catalyst to a continuous oxyalkylation reactor. Despite the continuous introduction of starter, the molecular weight distribution of the polyether product is quite narrow, as indicated by the exceptionally low polydispersity of the product. The presence of low molecular weight species during the majority of the polyoxyalkylation also substantially eliminates extremely high molecular weight fractions having molecular weights greater than 100,000 Da, again without appreciably broadening molecular weight distribution. By withdrawing intermediate molecular weight polyether product or diverting a portion of the end product to prepare a catalyst/starter mixture, rapid and sustained reaction rates can be achieved while employing low molecular weight starters. Continuous build ratios in excess of 0.98 can be achieved.
摘要:
The invention provides a polymer adapted for use in melt processes, the polymer having a thermally reversible bond which is adapted to evanesce at an elevated temperature and revert to a thermally reversible bond upon cooling to ambient temperature so that the polymer is adapted, upon being heated to the elevated temperature, to dissociate into melt processable polymeric fragments and, upon being cooled to ambient temperature, to re-associate. The thermally reversible bond is a bond that is capable of evanescing at a temperature which is lower than the degradation temperature of the polymer fragments. The thermally reversible bond may be, for example, a thermally reversible aromatic urethane bond.
摘要:
A superabsorbent polyurethane foam which contains a plurality of polycarbonyl moieties covalently attached to the polyurethane through at least one urethane, thiourethane, or urea linkage. The carbonyl portions of such polycarbonyl moieties can be carbamoyl, substituted carbamoyl, or carboxy or the alkali metal or ammonium salts thereof. The foam can be prepared by mixing an isocyanate-terminated prepolymer with a first compound having at least one isocyanate-reactive group and at least one carbon-carbon double bond, allowing the mixture to react, and then mixing with the resulting product an aqueous solution of a carboxylate-containing second compound having at least one carbon-carbon double bond. A thermally activated free radical initiator is present in the final reaction mixture.Preferably, the polyurethane is derived from an isocyanate-terminated poly(oxyalkylene) polyol having an isocyanate functionality greater than two and the polycarbonyl moieties are derived from second compounds which typically are acrylate or methacrylate salts, i.e., alkali metal or ammonium salts of acrylic or methacrylic acid. The first compound usually is the 2-hydroxyethyl ester of acrylic or methacrylic acid.Such superabsorbent polyurethane foam is useful in the manufacture of absorbent articles, especially disposable absorbent articles such as diapers, sanitary napkins, bedpads, incontinent pads, and the like.
摘要:
Thermally stable photopolymerizable compositions comprise(i) at least one nongaseous ethylenically unsaturated compound,(ii) a nitroso dimer which is a noninhibitor of free-radical polymerization but thermally dissociates to nitroso monomer which is an inhibitor of free-radical polymerization, and(iii) an organic, radiation-sensitive free-radical generating system.
摘要:
The present invention provides a process for the polyoxyalkylation of a starter involving establishing oxyalkylation conditions in an oxyalkylation reactor in the presence of a double metal cyanide (DMC) catalyst, continuously introducing into the reactor at least one alkylene oxide and an acidified, ultra-low water content starter, in which the starter contains greater than about 100 ppm and less than or equal to about 500 ppm water, based on the weight of the starter, and recovering an oxyalkylated low molecular weight starter polyether product. The inventive process allows the production of short chain polyether polyols which have hydroxyl numbers of from greater than 250 up to about 500, from hygroscopic initiators, such as glycerin, without DMC catalyst deactivation.
摘要:
During polyoxyalkylation in the presence of certain double metal cyanide catalysts, a very high molecular weight hydrophobic fraction, i.e. a "tail", is produced during preparation of high secondary hydroxyl polyols which is believed to contribute to foam collapse in polyurethane foam formulations. The processing latitude of such foams may be improved by altering the hydrophile/lipophile balance of the high molecular weight tail by oxyalkylating with a mixture of ethylene oxide and higher alkylene oxide during the greatest portion of total oxyalkylation such that essentially pure higher alkylene oxide is present in a terminal portion of oxyalkylation not exceeding 15 weight percent of total polyol weight.
摘要:
Double metal cyanide-catalyzed polyols are made by an improved process in which a starter is continuously added during polymerization of the epoxide. The process includes a continuously added starter (S.sub.c), and optionally, an initially charged starter (S.sub.i). The continuously added starter comprises at least about 2 equivalent percent of the total starter used. The process enables the use of water and low molecular weight polyol starters in DMC-catalyzed polyol synthesis. In addition, the process gives polyether polyols having reduced levels of high molecular weight polyol tail, which can adversely affect polyurethane foam processing.
摘要:
Oligomeric polyoxyalkylene polyethers are prepared by oxyalkylating a low molecular weight hydroxyl-functional starter molecule with one or more alkylene oxides in the presence of a solid, heterogeneous magnesium oxide catalyst. The catalyst is readily and rapidly removed by simple filtration to yield a polyether with minimal metal ion content suitable for use directly or as a starter molecule for further double metal cyanide complex catalyzed oxyalkylation.