Abstract:
The invention relates to a process for the preparation of polyether polyols by means of double metal cyanide (DMC) catalysts, in which the induction phase is shortened markedly. By continuous dispensing of an alkylene oxide into the starter-catalyst mixture it is possible to achieve a substantial shortening of the induction phase by comparison with the batch-wise activation.
Abstract:
Water soluble or water dispersible polyurethane, which are suitable as thickeners for aqueous systems and prepared from a selected alcohol component a) based on a hydrophilic/hydrophobic mixture of alcohols and an isocyanate component b), and to their use for thickening aqueous systems.
Abstract:
This invention relates to o-tolylenediamine-based polyether polyols having an OH number of about 400 to 630, in which about 5 to 20% of the isocyanate-reactive groups of the polyether polyols are secondary amino groups and which contain less than about 0.2% by weight free o-tolylenediamine. The polyether polyols of the invention are formed by sequential reaction of o-tolylenediamine first with about 2 to 5 mol of ethylene oxide and then with about 1 to 5 mol of propylene oxide per mol of o-tolylenediamine. This invention also relates to the process for the production of polyether polyols using said sequential reaction at a temperature of about 90.degree. to 125.degree. C. and in the presence of an amine catalyst. This invention further relates to a method for the production of polyisocyanate-based plastics, preferably polyurethane foams, comprising reacting organic polyisocyanates with polyether polyols of the invention and compounds containing at least two isocyanate-reactive hydrogen atoms and having a molecular weight range of about 200 to 1,500, and optionally also with chain-extending agents or crosslinking agents and auxiliaries or additives.
Abstract:
The present invention is directed to a process for the strengthening of geological formations in underground workings and mines by the introduction of reaction mixtures which react to form polyurethanes into the formations which are to be strengthened, the reaction mixtures being based on(a) a polyisocyanate component,(b) a polyol component and(c) an ester,the ester having a hydroxyl number of about 10 to 630 and an acid number of at most 10 and obtained from (i) an acid component having a carboxyl functionality of at least 1.5 and containing a polymerized fatty acid having at least 12 carbon atoms or mixtures thereof with unpolymerized saturated or unsaturated fatty acids having at least 12 carbon atoms and (ii) a polyol component containing at least one polyhydric alcohol, the ester being present in a positive amount of up to 5% by weight, based on the weight of component (b).
Abstract:
A superconducting fiber of a superconducting fiber bundle includes a carrier fiber having an outer surface, and superconducting layers and separating layers alternatingly surrounding the outer surface of the carrier fiber and a method for producing the same.
Abstract:
Superconducting fiber bundle which contains a multiplicity of carrier fibers such as, for instance, carbon fibers, boron fibers, steel fibers coated with a superconducting layer of a niobium compound of the general formula NbC.sub.x N.sub.y O.sub.z (x+y+z less than or equal to 1), characterized by the feature that the superconducting layer consists of fine-grained B1-structure niobium compound, the mean grain size of which is between 3 and 50 nm.
Abstract translation:含有多种载体纤维例如碳纤维,硼纤维,涂覆有通式NbC x N y O z的铌化合物超导层的钢纤维(x + y + z小于或等于1)的超导纤维束 ),其特征在于超导层由细粒度的B1结构的铌化合物组成,其平均晶粒尺寸在3和50nm之间。
Abstract:
Manufacture of superconducting fiber bundle coated with niobium carbonitride by a combination of the CVD process with a plasma activation under a low total gas pressure in which niobium chloride, carbon and nitrogen are reacted to produce the niobium compound which deposits from the gaseous phase on the carrier fiber to form a superconducting layer thereon. The combination of CVD process and plasma activation produces more uniform superconducting layers with smaller grain sizes. The application of an ultrasonic field may be combined with the CVD process. The superconducting layer consists of fine-grained B1-structure niobium compound, the mean grain size of which is between 3 and 50 nm.
Abstract:
A single-phase, storage-stable, emulsifier-free polyol mixture comprising 100 parts of a relatively high molecular weight polyoxyalkylene polyol of OH number from 20 to 120, which has at least 5% and less than 80% by weight, of terminal oxyethylene blocks; from 1 to 100 parts of a low molecular weight diol mixture which is a reaction product of ethylene glycol, butane diol-1,4, or a mixture of ethylene glycol and butane diol-1,4, with from 0.05 to 0.50 mols of alkyl oxiranes; from 0.1 to 5 parts of solubilizing additives comprising one or more salts, the cations of which are from Groups I, II and III of the Periodic Table, ammonium or mono- to tetra-alkyl ammonium ions, and the anions of which are produced by removing at least one proton from an acid having a K.sub.s value of at least 10.sup.-7 ; and, optionally, other compounds having isocyanate-reactive hydrogen atoms and other auxiliaries and additives for polyurethane production. Also polyurethanes produced using these polyol mixtures.
Abstract:
A process for the production of a flexible superconductor comprising a carbon fiber having thereon a layer of niobium carbonitride, and an outer layer of a highly conductive metal. Initially, niobium is deposited on the fiber, and the niobium-coated fiber is then exposed to gaseous sources of carbon and nitrogen while the temperature is subsequently raised.
Abstract:
The instant invention is directed to a novel process for the production of inorganic/organic plastic materials and the resultant products. The process generally comprises reacting an aqueous alkali metal silicate solution with a liquid organic polyisocyanate having a viscosity at 25.degree. C of at least about 400 cP. Preferably, the process is utilized to produce high quality, lightweight foams having excellent physical properties.