摘要:
A process for preparing organopolysiloxane compositions (A) having a viscosity measured at 25° C. of at least 500 Pa·s., wherein organopolysiloxanes (O) and fillers (F) are mixed and kneaded in a first process stage in a kneading cascade having at least two kneading chambers arranged in series adjacent one another, each containing kneading tools having parallel axes and capable of being driven in co-rotating or counter-rotating directions, the chambers connected to one another by means of openings through which material can pass in a direction transverse to the axes of the kneading tools, with the first kneading chamber having a feed opening and the last kneading chamber having a discharge opening, to give raw mixtures, and the raw mixtures are kneaded and degassed in a reciprocating kneader in a second process stage.
摘要:
The present invention relates to heat-transfer concentrates for solar installations, containing a) from 92 to 99% by weight of at least one polyglycol of the formula R—O—(CH2—CH2—O)n—H, in which n is an integer of from 3 to 500 and R is H, a C1- to C4-alkyl group or an aromatic radical having 6 to 12 carbon atoms, b) from 1 to 8% by weight of at least one corrosion inhibitor, with the proviso that its content of ethylene glycol and 1,2-propylene glycol is less than 0.2% by weight.
摘要:
A process for the continuous production of organopolysiloxane compositions which vulcanize at elevated temperature and have a viscosity of at least 500 Pa·s at 25° C., involves mixing and homogenizing high-viscosity organopolysiloxanes and crosslinking additives in a kneading cascade having at least two kneading chambers arranged in series proximate one another, containing two axially parallel kneading tools which can be driven in the same or opposite directions, and which are connected to one another by means of openings transverse to the axes of the kneading tools, with the first kneading chamber having a feed opening and the last kneading chamber having a discharge opening, and the temperature in the kneading chambers containing crosslinking additives being not more than 95° C.
摘要:
The invention relates to a dynamic gas mounting of a motor spindle, with a rotating shaft 2 which is gas-mounted in a housing 3 in the radial and axial direction, at least one radial gas bearing 4 being present for radial mounting along the shaft 2 and at least two axial gas bearings 5, 6 being present for the axial mounting of the shaft 2, and the two axial gas bearings 5, 6 having different surface profiles 12 for generating a flow of the bearing gas in the axial direction 14 of the shaft 2 in order to vent the mounting.
摘要:
A gradient coil system for a magnetic resonance apparatus has gradient coils and at least one cooling tube for cooling the gradient coils using a coolant flowing through the cooling tube. The cooling tube is formed of a flexible thermoplastic material, augmented with a filler, and has a thermal conductivity greater than 0.5 W/mK.
摘要:
A process for the continuous preparation of addition-crosslinking silicone rubbers from a base composition containing at least one polyvinyl polysiloxane and at least 10% by weight, based on the liquid silicone rubber, of hydrophobicized filler, by removing the base composition from a container whose volume reduces proportionally with the amount removed, and conveying the composition by way of a pump with a positive pressure difference to two further pumps (4) which convey the base composition onward, so a component A is prepared continuously by admixing at least one metal catalyst with one stream of the base composition, and a component B is prepared continuously and simultaneously by admixing the crosslinker and inhibitor with a second stream of the base composition, where the metal catalyst, crosslinker, and inhibitor are fed by way of a feed unit which meters in each of the substances.
摘要:
The invention relates to a concentrate for a heat transfer medium for solar units, comprisinga) from 45 to 98% by weight of triethylene glycol and/or tetraethylene glycol,b) from 1 to 55% by weight of 1,2-propylene glycol and/or ethylene glycol, andc) from 1 to 6% by weight of corrosion inhibitors.The concentrate is used in admixture with water for heat transport in solar units.
摘要:
The organopolysiloxane compositions are prepared by mixing(1) organopolysiloxanes which contain on average at least 2 aliphatic carbon-carbon multiple bonds per molecule,(2) prehydrophobized oxidic reinforcing fillers having a carbon content, obtained by the hydrophobizing, of at least 0.5% by weight and(3) compounds which are chosen from(3a) silanol compounds of the formulaR--[SiR.sub.2 --O--].sub.a H (I)in whichR is identical or different monovalent, C.sub.1 - to C.sub.10 -hydrocarbon radicals which are free from aliphatic carbon-carbon multiple bonds anda has values from 1 to 10, and(3b) saturated C.sub.1 - to C.sub.18 -alkanols.
摘要:
In a method for reducing noise during operation of a magnetic resonance apparatus, a gradient coil which exhibits a vibratory node during operation of the apparatus is attached to a holder exclusively in a region of the vibratory node. In a magnetic resonance apparatus, a gradient coil having at least one vibratory node along a longitudinal length thereof during operation of the magnetic resonance apparatus is attached to the holder exclusively in a region of the vibratory node.
摘要:
A process for purifying organopolysiloxanes, which comprises treating organopolysiloxanes after their preparation with an elemental metal. Impurities which are related to the preparation of organopolysiloxanes and cause changes in color, in particular during storage under the influence of heat, subsequent clouding, inhibition of catalysts, a lack of heat stability, a lack of dielectric strength or the formation of odors, especially after exposure to light, are removed by the process of this invention.