摘要:
The surface-modified polymethylsilsesquioxane spherical fine particles of this invention comprise polymethylsilsesquioxane spherical fine particles serving as nuclei, and at least one member of an alkyl group having two or more carbon atoms, an alkenyl group, a phenyl group, an epoxy group, an acryloxy group and an amino group is bonded to the surface of a particle. They are prepared by a process comprising the step of carrying out reaction in an aqueous suspension of polymethylsilsesquioxane fine particles in the presence of an alkali catalyst. The surface-modified spherical fine particles can have various organic groups on their surfaces, and are used in various fields such as rubbers, plastics, coating materials, inks, and cosmetics, depending on the types of the organic groups.
摘要:
A method for manufacturing synthetic silica glass by reacting methyl silicate and aqueous ammonia, dispersing the silica particles produced in water, solidifying the silica by the addition of methyl silicate and heating, dehydrating, de-solventing, decarburizing and sintering the solid silica to produce a glass product. The sintered glass may be pulverized to produce a powder. The inventive method is easily carried out and avoids the high energy costs of the prior art. The glass product obtained exhibits excellent high temperature viscosity.
摘要:
A process for producing fine spherical silica, comprising a step of hydrolyzing an alkoxysilane in a mixed solution comprising water and alcohol and containing an alkaline catalyst, wherein the amount of said alkaline catalyst is 0.5 to 10 in molar ratio to the alkoxysilane used, the concentration of water in said mixed solution of water and alcohol in 5 to 20 mol/lit., and the reaction temperature for said hydrolysis is 30.degree. C. or more.According to this process, there can be obtained highly monodisperse spherical silica containing only a very small amount of impurities and having a particle size of 100 nm or less.
摘要:
This invention is a method for preventing sticking of a resin plate surface by coating the solution of binder and photopolymerizable monomer on the surface of a photosensitive resin composed of binder, photopolymerizable monomer, and photopolymerization initiator, developing relief images by a photomechanical process, and then by drying the coating solution.
摘要:
The present invention provides a method for obtaining high purity chlorosilanes from chlorosilanes containing boron impurities and phosphorus impurities. On the basis of the finding that solid by-product formation in the purification of chlorosilanes by adding an aromatic aldehyde results from a catalytic reaction by iron ions or rust-like iron, a Lewis base having a masking effect is added to chlorosilanes. Examples of the Lewis base include a divalent sulfur-containing compound and an alkoxysilane. The divalent sulfur-containing compound is preferably a compound represented by the formula: R—S—R′ (wherein R is a hydrocarbon group or a carbonyl group; and the sum of the carbon atoms in R and R′ is 7 or more), and the alkoxysilane is preferably a compound represented by the formula: RxSi(OR′)4-x (wherein R and R′ are each an alkyl group having 1 to 20 carbon atoms).
摘要:
A by-product mixture produced in a process for producing polycrystalline silicon is made to react with chlorine to form tetrachlorosilane (STC) distillate in a chlorination reaction vessel, and the tetrachlorosilane (STC) distillate is made to react with hydrogen in a hydrogenation reaction vessel to be converted into trichlorosilane (TCS). In the chlorination step, methyl chlorosilanes having boiling points close to TCS are hyper-chlorinated to be converted into hyper-chlorinated methyl chlorosilanes having higher boiling points, which facilitates the hyper-chlorinated methyl chlorosilanes to be separated into high concentration, and inhibits carbon from contaminating the polycrystalline silicon. A donor/acceptor eliminator is provided in the circulation cycle for producing TCS, and accordingly there is no need to take out a by-product produced in the process for producing TCS to the outside of the system, which can highly purify the TCS.
摘要:
A barcode scanner comprising a laser driving circuit to drive a laser by a pulse signal generated by an oscillator, a preamplifier to amplify a voltage of a barcode signal from a photodetector corresponding to a reflected light from a barcode scanned by a light output of the laser driven by the pulse signal, a high-pass filter to remove a direct current component contained in an output signal of the preamplifier, a variable gain amplifier which controls an amplification gain of an output signal of the high-pass filter and performs automatic gain control to set an output level almost constant, a synchronous detector to detect a pulse signal contained in an output signal of the variable gain amplifier in synchronization with the output pulse of the oscillator, and a binarization circuit to binarize an output signal of the synchronous detector.
摘要:
This invention provides twisted nematic liquid crystal compositions obtained by adding a cyclohexane ring-containing optically active compound of the following general formula (1) to a mixture of nematic liquid crystal compounds including at least one silacyclohexane compound, as well as guest-host liquid crystal compositions and liquid crystal display devices utilizing the same. ##STR1##
摘要:
Silacyclohexane compounds of the following formula (I) or (II) along with intermediate compounds therefor are described ##STR1## wherein R is an organic residue, one of ##STR2## represents a trans-1-sila-1,4-cyclohexylene group or trans-4-sila-1,4-cyclohexylene group having a substituent of H, F, Cl or CH.sub.3, and the other represents a trans-1,4-cyclohexylene group, or such a trans-1-sila-1,4-cyclohexylene group or trans-4-sila-1,4-cyclohexylene group as defined above, n is 0 or 1, L.sub.1 represents H or F, L.sub.2 represents H, F or Cl, and Z represents CN, F, Cl or an organic residue, and ##STR3## The processes for preparing the compounds (I) and (II) are also described along with liquid crystal compositions comprising the compounds and the liquid crystal devices comprising the compositions.
摘要:
A silacyclohexane compound represented by the following general formula (I). ##STR1## In this formula, R denotes a linear-chain alkyl group with a carbon number of 1-10, a mono- or di- fluoro-alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, or an alkenyl group with a carbon number of 2-8. ##STR2## denotes trans-1-sila-1,4-cyclohexylene or trans-4-sila-1,4-cyclohexylene group whose silicon at position 1 or position 4 has a substitutional group(s) of H, F, Cl or CH.sub.3. X denotes a CN, F, Cl, CF.sub.3, CF.sub.2 Cl, CHFCl, OCF.sub.3, OCHF.sub.2, OCF.sub.2 Cl, OCHFCl, R or OR group (R is the same as defined in the general formula (I)). Y.sub.2 and Z denote H or F, independently to each other. Y.sub.1 denotes H, F or Cl.