摘要:
Polyethercyclicpolyols are prepared by thermally condensing a polyol having at least three hydroxyl groups of which at least two of the hydroxyl groups are vicinal, precursors of the polyol, cyclic derivatives of the polyol, or mixtures thereof, and controlling process conditions to avoid substantial undesirable degeneration. Lower molecular weight polyethercyclicpolyols are copolymerized with epoxy resins to form higher molecular weight polyethercyclicpolyols.
摘要:
Polyethercyclicpolyols are prepared by thermally condensing a polyol having at least three hydroxyl groups of which at least two of the hydroxyl groups are vicinal, precursors of the polyol, cyclic derivatives of the polyol, or mixtures thereof, and controlling process conditions to avoid substantial undesirable degeneration. Lower molecular weight polyethercyclicpolyols are copolymerized with epoxy resins to form higher molecular weight polyethercyclicpolyols.
摘要:
Method for preparing polyethercyclicpolyol by heating a reaction mixture of an alkali or alkaline earth metal hydroxide with a polyol, adding epihalohydrin to initiate an addition reaction, and heating the mixture until the reaction is complete.
摘要:
Method for preparing polyethercyclicpolyol by heating alkali and/or alkaline earth hydroxide optionally with polyol, its precursors or derivatives, admixing epoxy alcohol or epihalohydrin therewith to initiate an addition reaction, and thermally condensing the product of the addition reaction.
摘要:
Polyethercyclicpolyols are prepared by thermally condensing a polyol having at least three hydroxyl groups of which at least two of the hydroxyl groups are vicinal, precursors of the glycol, cyclic derivatives of the polyol, or mixtures thereof, and controlling process conditions to avoid substantial undesirable degeneration. Lower molecular weight polyethercyclicpolyols are polycondensed with epoxy alcohols to form higher molecular weight polyethercyclicpolyols.
摘要:
Polyethercyclicpolyols are prepared by thermally condensing a polyol having at least three hydroxyl groups of which at least two of the hydroxyl groups are vicinal, precursors of the polyol, cyclic derivatives of the polyol, or mixtures thereof, and controlling process conditions to avoid substantial undesirable degeneration. Lower molecular weight polyethercyclicpolyols are polycondensed with epoxy alcohols to form higher molecular weight polyethercyclicpolyols.
摘要:
Polyethercyclicpolyols are prepared by thermally condensing a polyol having at least three hydroxyl groups of which at least two of the hydroxyl groups are vicinal, precursors of the polyol, cyclic derivatives of the polyol, or mixtures thereof, and controlling process conditions to avoid substantial undesirable degeneration. Lower molecular weight polyethercyclicpolyols are polycondensed with epihalohydrins to form higher molecular weight polyethercyclicpolyols.
摘要:
A method for providing means for energizing a capacitive load. The capacitive load is connected to an alternating current power source by using a connecting device. The connecting device comprises at least one diode and connecting organs, which can be closed or open.
摘要:
In capacitor equipment which includes a series-connection, connected to an alternating voltage network, of two anti-parallel connected thyristors, one capacitor and one reactor, a control device is connected to the control electrode of the thyristors and arranged to ignite the thyristors alternately at times in the vicinity of the peak value of the alternating voltage. A sensing member is provided for sensing an operating magnitude in the series connection and a level-sensing member is connected to the sensing member and to the control device. The level-sensing member influences the control device to produce ignition of both thyristors of the instantaneous value of the operating magnitude falls outside a pre-determined interval.
摘要:
A capacitor bank for power factor correction and/or voltage control is connectible to an AC network through a bidirectional static switch. Voltage sensing and comparing means effect connection of the capacitor bank to the network at the moment when the instantaneous values of the mains and capacitor voltages coincide. During a predetermined time interval after disconnection of the capacitor bank from the network, the switch is periodically made conducting for keeping the capacitor charged with a voltage of constant polarity. After the end of this time interval, the switch is made non-conducting, whereby the capacitor is allowed to discharge through the discharge resistor.