摘要:
The invention relates to a method of preparing wholly aromatic polyester including: mixing monomers, introducing the mixed monomers into a reactor having a rectangular or trapezoidal plate type stirring impeller, and polymerizing the introduced monomers through esterification with a power per unit volume of 10˜60 kW/m3, a length (L) to diameter (D) ratio of the stirring impeller is 1˜3:1, and a distance between the bottom of the reactor and a lower portion of the stirring impeller is 1/100˜ 1/15 times of the diameter (D); b) pulverizing the obtained polymer; and c) solid state polymerizing the pulverized polymer. The present invention also relates to a method of preparing wholly aromatic polyester having excellent heat resistant properties in which byproduct is effectively discharged by controlling a heating rate and reaction holding time between the weight loss initiating temperature and the melting point of a low molecular weight polymer generated in a melt polymerization in a solid state polymerization, adhesion does not occur, and discoloration due to heating does not occur.
摘要:
Disclosed are a production method for a wholly aromatic liquid crystalline polyester resin, a wholly aromatic liquid crystalline polyester resin produced using the method, and a compound of the wholly aromatic liquid crystalline polyester resin. The disclosed production method for a wholly aromatic liquid crystalline polyester resin comprises the steps of synthesizing a wholly aromatic liquid crystalline polyester resin by synthesizing a wholly aromatic liquid crystalline polyester prepolymer by a condensation polymerization of a monomer and then reducing the pressure inside a reaction vessel containing the synthesized prepolymer at a predetermined internal pressure reduction rate of the reaction vessel.
摘要:
Provided is a method of preparing a wholly aromatic liquid crystalline polyester resin and a wholly aromatic liquid crystalline polyester resin prepared by the method, and a compound of the wholly aromatic liquid crystalline polyester resin. The disclosed method of preparing the wholly aromatic liquid crystalline polyester resin includes a step (a first temperature increasing step) of increasing the temperature of a reaction mixture including at least one monomer at a first temperature increasing rate up to a first temperature; a step (an isothermal maintaining step) of maintaining the reaction mixture that passed through the first temperature increasing step at the first temperature for a first time; and a step (a second temperature increasing step) of increasing the temperature of the reaction mixture that passed through the isothermal maintaining step at a second temperature increasing rate.
摘要:
Disclosed are a production method for a wholly aromatic liquid crystalline polyester resin, a wholly aromatic liquid crystalline polyester resin produced using the method, and a compound of the wholly aromatic liquid crystalline polyester resin. The disclosed production method for a wholly aromatic liquid crystalline polyester resin comprises the steps of synthesizing a wholly aromatic liquid crystalline polyester resin by synthesizing a wholly aromatic liquid crystalline polyester prepolymer by a condensation polymerization of a monomer and then reducing the pressure inside a reaction vessel containing the synthesized prepolymer at a predetermined internal pressure reduction rate of the reaction vessel.
摘要:
Disclosed are a wholly aromatic liquid crystal polyester resin compound, a preparation method thereof, parts for optical pickup, and a preparation method thereof. The disclosed wholly aromatic liquid crystal polyester resin compound comprises two kinds of wholly aromatic liquid crystal polyester resins having different melting points and an additive, and most of the terminal groups in the resins having lower melting points among the resins comprise a carboxyl group.
摘要:
The present invention relates to an overvoltage repetition prevention circuit, a method thereof, and a power factor correction circuit including the same. The power factor correction circuit includes: an inductor receiving an input voltage and supplying an output voltage; a power switch connected to the inductor and controlling an inductor current to the inductor; and a power factor correction controller differently controlling a control structure generating a control voltage controlling a switching operation of the power switch during a predetermined overvoltage stabilization period generated in synchronization with a time that an output voltage is an overvoltage and the control structure generating the control voltage in a normal state in which the output voltage is not the overvoltage, wherein the control structure is determined according to a difference between the output voltage and a predetermined output target voltage during the overvoltage stabilization period.
摘要:
The present invention relates to an energy-saving anti-corrosive metal film composition and manufacturing method for the same. The energy-saving anti-corrosive metal film composition includes: at least one metal powder selected from the group consisting of aluminum, magnesium, and alloys thereof, having particle size of 5-10 um; a first sol-gel resin selected from the group consisting of zirconium tetra-n-butanolate, zirconium butoxide, isopropyl titanate, and mixtures thereof; a second sol-gel resin selected from the group consisting of tris[3-(trimethoxysilyl)propyl] isocyanurate, gamma-meta-acryloxypropyl trimethoxysilane and n-phenyl-gamma-aminopropyltrimetoxysilane, and mixtures thereof; and a solvent.
摘要:
A cooling unit cooling a coil assembly that generates electromagnetic force for driving a nuclear reactor control rod, and including a coil surrounding a driving shaft of the nuclear reactor control rod so as to generate the electromagnetic force; a coil housing surrounding the coil so as to enclose the coil; a cooling shroud-shell forming a cooling flow path between the cooling shroud-shell and the coil housing, whereby a cooling fluid for cooling heat that is generated in the coil passes through the cooling flow path; and a plurality of cooling fins disposed on the cooling flow path in a radial direction so as to allow heat to be effectively exchanged between the coil and the cooling fluid that flows through the cooling flow path.
摘要:
Disclosed are a light emitting device package and a lighting system. The light emitting device package includes a body including a cavity, at least one light emitting device in the cavity, a resin member filled in the cavity while covering the light emitting device, and a reflective layer on a lateral side of the cavity. The reflective layer is formed while opening the upper region of the cavity. The reflective layer is selectively formed only in a lower region of the lateral side of the cavity in the body, and the resin member, which is filled in the upper portion of the cavity, directly adheres to the body. The air-tightness between the resin member and the body is improved.
摘要:
A white Light Emitting Diode (LED) device that enables the adjustment of a Correlated Color temperature to realize emotional illumination is provided. The white LED device includes a package body for accommodating a plurality of light source units; a first light source unit accommodated in the package body, configured to have one or more first LED chips and a first phosphor, and configured to emit white light having a first Correlated Color Temperature (CCT); a second light source unit accommodated in the package body, configured to have one or more second LED chips and a second phosphor, and configured to emit white light having a second CCT; and a current control unit for varying current, to be supplied to at least one of the first and second LED chips, so as to adjust the first and second CCTs.