摘要:
The invention relates to a highly-structured precipitated silica having a low water uptake and high dispersibility in different pasty or solid matrices or media, elastomers or silicon, and to the preparation method thereof. The invention also relates to the use of said silica, for example, as a reinforcing filler in matrices based on elastomers (clear or semi-clear for shoe soles), in silicon matrices (in particular, for the coating of electric cables), as a filler and/or support and/or vehicle in different compositions (food compositions, cosmetic compositions, pharmaceutical compositions, compositions for the production of paints or paper, compositions for the production of porous membrane separators for batteries) or as a thickening agent in toothpastes.
摘要:
The invention concerns a method for preparing low water uptake precipitated silicas, comprising successive steps which consist in: (a) producing an initial starter including a silicate, the silicate concentration in said starter, expressed in SiO2 equivalent, being less than 15 g/L; (b) bringing the medium pH to a value ranging between 7 and 8 by adding an acidifying agent, (c) in the resulting medium, simultaneously adding a silicate and an acidifying agent the respective amounts of silicate and acidifying agent added in time being specifically such that, during the entire addition (1) the reaction medium pH stays between 7 and 8, and (ii) the silicon concentration in the medium, expressed in SiO2 equivalent, stays below 35 g/L; (d) adding an acidifying agent in the medium resulting from step (c), so as to bring the medium to a pH ranging between 3 and 6.5; and (e) filtering the resulting aqueous silica dispersion, then drying the filter cake obtained at the end of the filtering step. The invention also concerns low water uptake silicas obtained by said method and their use, in particular for reinforcing silicones or polymer or elastomer matrices.
摘要:
The invention concerns a method for preparing low water uptake precipitated silicas, comprising successive steps which consist in: (a) producing an initial starter including a silicate, the silicate concentration in said starter, expressed in SiO2 equivalent, being less than 15 g/L; (b) bringing the medium pH to a value ranging between 7 and 8 by adding an acidifying agent, (c) in the resulting medium, simultaneously adding a silicate and an acidifying agent the respective amounts of silicate and acidifying agent added in time being specifically such that, during the entire addition (1) the reaction medium pH stays between 7 and 8, and (ii) the silicon concentration in the medium, expressed in SiO2 equivalent, stays below 35 g/L; (d) adding an acidifying agent in the medium resulting from step (c), so as to bring the medium to a pH ranging between 3 and 6.5; and (e) filtering the resulting aqueous silica dispersion, then drying the filter cake obtained at the end of the filtering step. The invention also concerns low water uptake silicas obtained by said method and their use, in particular for reinforcing silicones or polymer or elastomer matrices.
摘要:
The invention relates to a novel method of preparing silicas and to highly-structured silicas having the following characteristics: a specific surface area CTAB (SCTAB) of between 40 and 525 m2/g; a specific surface area BET (SBET) of between 45 and 550 m2/g; an object size distribution width Ld ((d84−d16)/d50), which is measured by XDC particle size analysis after deagglomeration with ultrasound, of at least 0.91; and a pore-size distribution such that ratio V(d5−d50)/V(d5−d100) is at least 0.66. The invention also relates to the use of said silicas as polymer reinforcing fillers.
摘要:
The invention relates to a method of controlling the level of corrosivity of an aqueous solution recovered during a process for producing a blanket of mineral fibers, comprising in particular the fiberizing and the coating of said fibers with a binder comprising a polyacid typically of the acrylic type, said aqueous solution being at least partly recycled into a zone in which said resin is prepared and/or a scrubbing zone of the production plant, said method being characterized in that the pH of the solution in the recycling circuit is maintained between minimum and maximum values by injecting into said circuit an agent for modifying said pH, such as a base, the quantity injected or the flow rate of the pH-modifying agent being adjusted directly according to the quantity or the flow rate of acid binder injected during the fiberizing process.The invention also relates to the device for implementing the method.
摘要:
The invention concerns compounds, for use as liquid support and as anticaking agent, and, simultaneously, as nutrient additive in particular for animals, consisting of precipitated silica and phosphate selected among phosphates of elements of groups Ia or IIa of the periodic table of the elements and rare-earth phosphates, said compounds being in the form of substantially spherical pellets.
摘要:
The invention relates to a novel method of preparing silicas and to highly-structured silicas having the following characteristics: a specific surface area CTAB (SCTAB) of between 40 and 525 m2/g; a specific surface area BET (SBET) of between 45 and 550 m2/g; an object size distribution width Ld ((d84−d16)/d50), which is measured by XDC particle size analysis after deagglomeration with ultrasound, of at least 0.91; and a pore-size distribution such that ratio V(d5−d50)/V(d5−d100) is at least 0.66. The invention also relates to the use of said silicas as polymer reinforcing fillers.
摘要:
Carboxylic acids are employed during the preparation of precipitated silica or a suspension of precipitated silica to provide precipitated silicas with low water uptake, which are useful, for example, as reinforcing fillers for silicon matrices.
摘要:
Diene rubber compositions are described containing a diene elastomer, a reinforcing inorganic filler, and a coupling agent wherein the inorganic filler includes a silica having the following characteristics: (a) a BET specific surface area between 45 and 400 m2/g; (b) a CTAB specific surface area between 40 and 380 m2/g; (c) an average particle size (by mass), dw, of 20 to 300 nm; and at least one of the following characteristics, preferably two and more preferably all three: (d) a particle size distribution such that dw≧/CTAB)−30; (e) a porosity which meets the criterion L/FI≧−0.0025 CTAB+0.85; (f) an amount of silanols per unit of surface area, NSiOH/nm2; NSiOH/nm2≦−0.027 CTAB+10.5. These diene rubber compositions can be used for the manufacture of tires or of semi-finished products intended for tires.