摘要:
A precipitated silica having an SiOHisolated absorbance ratio of greater than or equal to 1.5, a silanol group density of 1 to 3.0 SiOH/nm2, a modified tapped density of 1 to 50 g/l, and a pH of 3-5, when measured as a aqueous suspension of 5.00 g of the precipitated silica in 100 ml. of deionized water allows preparation of storage-stable RTV-1 silicone rubber formulations without stabilizer. A process for preparing the precipitated silica and its use in thickening sealants is provided.
摘要:
A precipitated silica having an SiOHisolated absorbance ratio of greater than or equal to 1.5, a silanol group density of 1 to 3.0 SiOH/nm2, a modified tapped density of 1 to 50 g/l, and a pH of 3-5, when measured as a aqueous suspension of 5.00 g of the precipitated silica in 100 ml. of deionized water allows preparation of storage-stable RTV-1 silicone rubber formulations without stabilizer. A process for preparing the precipitated silica and its use in thickening sealants is provided.
摘要:
Hydrophilic precipitated silicas which combine a particularly low initial moisture content with low moisture absorption over time, a low tapped density and a low silanol group density, have the following physicochemical parameters: equilibrium moisture content (at 70% relative humidity/20° C.) of 0.5%-5.0% by weight, based on the weight of the hydrophilic precipitated silica, BET surface area of 50-250 m2/g, CTAB surface area of 50-250 m2/g, and DBP (anhydrous) of 200-350 g/100 g.
摘要:
Precipitated silicas having an SiOHisolated absorbance ratio of greater than or equal to 1, may be used as reinforcers and thickeners for sealants.
摘要:
Hydrophilic precipitated silicas which combine a particularly low initial moisture content with low moisture absorption over time, a low tapped density and a low silanol group density, have the following physicochemical parameters: equilibrium moisture content (at 70% relative humidity/20° C.) of 0.5%-5.0% by weight, based on the weight of the hydrophilic precipitated silica, BET surface area of 50-250 m2/g, CTAB surface area of 50-250 m2/g, and DBP (anhydrous) of 200-350 g/100 g.
摘要:
The present invention relates to a method of purifying strong acids or strongly acidic media to remove di- and higher valent metal ions, which can be used within the context of the production of high-purity silica. The invention further relates to the use of special ion exchangers for carrying out the method according to the invention and the resultant high-purity silicas.
摘要:
The invention relates to a novel method for producing high-purity SiO2 from silicate solutions, a novel high-purity SiO2 with a specific impurity profile and use thereof.
摘要:
It has been found that conventional cheap waterglass qualities in a strongly acidic medium react to give high-purity silica grades, the treatment of which with a base leads to products which can be processed further to give glass bodies with low silanol group contents.
摘要:
The invention relates to a novel method for producing high-purity SiO2 from silicate solutions, a novel high-purity SiO2 having a specific impurity spectrum and use thereof.
摘要:
A controller unit includes a PI-controller for harmonic command variables. The transfer function of the PI-controller has a conjugate complex pole at a controller angular frequency ωr in the s-plane or a pole at e±jωrT in the z-plane, wherein T is the sampling time of a discrete input signal of the PI-controller and ωr is larger than 0. The controller angular frequency ωr is chosen equal to the resonance angular frequency ω0 of an oscillator. The controller parameters, are, for example determined by pole/zero compensation. The controller unit allows, for example, a broad band control of harmonic oscillators in rotation rate sensors.