摘要:
The method is based on the fact that the particular components are conveyed through separate pipes into a mixing chamber. By measuring the transit time in at least one of the pipes the flowrate can be measured. The flow in the other pipes which is in a fixed ratio to the first flow is then adjusted automatically. For measuring the transit time a heat pulse is injected in at least one of the pipes and the transit time of the heat impulse is measured. The so-measured transit time is converted into an inversely proportional voltage and the flowrate in the other pipes is adjusted proportionally to this voltage. An apparatus is provided for practicing the method. The apparatus comprises flow measuring elements which are electrical connected to control devices which operate flow control devices in the pipes leading to the mixing chamber.
摘要:
The instant invention is directed to new liquid bicycloaliphatic triisocyanates and to the use thereof as the isocyanate component in the production of polyurethane plastics by the known isocyanate-polyaddition process. The new triisocyanates are particularly suitable for use as the isocyanate component in low-solvent, light-stable two-component polyurethane lacquers.
摘要:
The invention relates to blends of polyarylene sulfides, epoxides, glass fibers, optionally anhydride-containing polymers and optionally other additives. They are distinguished by good mechanical properties.
摘要:
Molded articles are produced in a two-stage process. In the first stage, an organic polyisocyanate is reacted with an organic compound containing at least two epoxide groups (NCO: epoxide equivalent ratio of 1.2:1 to 500:1) in the presence of a tertiary amine catalyst. This reaction is stopped when no more than 65% of the isocyanate groups have reacted by adding an alkylating sulfonic acid alkyl ester of methyl iodide and/or of dimethyl sulfate in an amount equivalent to the amount of tertiary amine catalyst present. A latent catalyst capable of being activated by heat is subsequently added to the intermediate product and the resultant mixture is heated in a mold to complete the crosslinking of the intermediate product and to form the molded article.
摘要:
The present invention relates to a process for the production of metal effect lacquerings having improved weather-resistance by the multilayered lacquering of various substrates, using a clear layer as top coat and a lacquer containing metal pigments to form the outer layer of the multilayered lacquering which is covered by the layer of clear lacquer, characterized in that the clear lacquer used is one the main binder of which is a two-component system consisting of:(a) a polyol component consisting essentially of polyester polyols having a low aromatic component content and optionally also polyacrylate polyols; and(b) a polyisocyanate component having biuret and/or isocyanurate groups, as well as aliphatically-bound isocyanate groups which may be blocked with isocyanate blocking agents. The present invention also relates to the substrates coated with these lacquers.
摘要:
The present invention is concerned with an improved process for the production of partially trimerized hexamethylene diisocyanate which yields isocyanurate isocyanates which have low viscosity and low monomer contents by the use of a quaternary ammonium hydroxide catalyst which is hydroxyalkyl substituted at its N atom.
摘要:
This invention discloses mixtures for use as binders for solvent-free lacquers which are liquid at room temperature, can be prepared in the presence of moisture and have good light stability and resistance to weather.The mixtures contain:(a) at least one organic polyisocyanate which contains aliphatically bound isocyanate groups;(b) at least one polyhydroxyl compound with a molecular weight of 200 to 2000 which is free from ether groups; and(c) 0-40 percent by weight, based on the total mixture of monohydric and/or polyhydric alcohols with a molecular weight below 200;the components of the mixture being used in such quantities that the NCO/OH ratio is between 0.8:1 and 1.2:1.
摘要:
The instant invention provides a method for determining the streaming velocity of a streaming liquid by injecting a thermopulse into the liquid and measuring its transit time. The pulse is detected by its ascending flank at downstream points and by its ascending or descending flank at its point of injection. For short transit times, provision is made to eliminate the heat up time of the heating wire imparting the pulse from the transit time measurement. The liquid may stream continuously or discontinuously, and if the later, provision is made to delay measurement on initiation of flow until the flow pattern has stabilized. The time is determined by counting pulses from a pulse generator during the period the pulse is traveling between the point of injection and a detection point or between two detection points.
摘要:
A process for the production of a crosslinkable low-molecular weight acrylic resin containing hydroxyl-groups and having a low-molecular consistency factor by the radical bulk copolymerization of(A) 0 to 30 parts by weight of a hydroxyalkyl ester of acrylic acid or methacrylic acid or mixtures thereof;(B) 0 to 60 parts by wt. of styrene or a substituted styrene or methyl methacrylate or mixtures thereof;(C) 10 to 90 parts by weight of an acrylic acid ester or of a methacrylic acid ester with 2 to 12 carbon atoms in the alcohol radical or mixtures thereof;(D) 0 to 30 parts by weight of an .alpha.,.beta.-monoolefinically saturated mono- or di-carboxylic acid with 3 to 5 carbon atoms or of a maleic acid semiester or mixtures thereof or reaction products thereof with a monoglycidyl compound, in the presence of 10 to 70 parts by weight of a monoallyl ether of an at least trihydric alcohol,The sum of the parts by weight of all the monomers A - E amounting to 100,Wherein the indicated quantity of monomer E is initially introduced and, at temperatures above 100.degree. C, monomers A to D together with 0.5 to 6% by weight, based on A to D, of an initiator with a half-life period at 100 to 160.degree. C of 0.01 to 100 minutes, are introduced over a period of 1 to 6 hours and polymerized, at least 98% by weight of the monomers A to D and from 36 to 95% by weight of monomer E being converted. Acrylate resins of this type are eminently suitable for the production of readily processible binder mixtures which although low in viscosity, have a very high solids content.
摘要:
The present invention is concerned with a process for producing biuret polyisocyanates and the polyisocyanates so produced. These isocyanates are produced by the reaction of at least about a four fold molar excess of a diisocyanate having aliphatically bound isocyanate groups with amino alcohols having a particular structure at a temperature between about 90 and 200.degree. C. The amino alcohols contain at least three carbon atoms, have their hydroxyl and amino groups separated by at least two carbon atoms, and may contain urea, urethane, ether or amino bonds. The present invention is also concerned with a process for producing two component and one component moisture curing lacquers using the biuret polyisocyanates of the present invention and the lacquers so produced.