摘要:
Reinforced precipitated silica having, on a coating-free and impregnant-free basis, a surface area of from about 220 to about 340 square meters per gram, a pore diameter at the maximum of the volume pore size distribution function of from about 9 to about 20 nanometers, and a total intruded volume of from about 2.6 to about 4.4 cubic centimeters per gram, is produced by a process wherein precipitated silica is heavily reinforced using a multiplicity of precipitation and aging steps.
摘要:
Described are high solids aqueous slurries of amorphous precipitated hydrated silica, which slurries are of relatively low viscosity. The slurry typically contains from about 40 to about 60 weight percent of hydrated precipitated high structure silica. The viscosity of the high solids slurry is less than about 1000 centipoises. Processes for producing the aqueous high solids silica slurry are disclosed. In one embodiment, a wet cake of amorphous precipitated hydrated silica is liquified and the liquified wet cake charged to a high intensity mill wherein the silica is wet milled until the median agglomerate particle size of the silica is between about 0.3 and about 3 microns. In a further embodiment, finely-divided dry amorphous precipitated silica is slurried in a dispersion mill to the desired solids level and this slurry charged to a high-intensity mill and wet milled therein until the aforesaid agglomerate particle size range is attained. The resulting high solids slurry can be shipped in bulk with only mild agitation to prevent setting. A dispersant may also be added to the slurry prior to milling to retard settling of the silica.
摘要:
Free flowing, substantially dust-free, dense granular amorphous precipitated silica having a principal particle size of between about 0.14 millimeters and about 0.84 millimeters are described. This material is particularly suitable as an inert carrier for water-soluble and fat soluble nutritional supplements, e.g., vitamins, which are added to feeds for livestock.
摘要:
A method for the preparation of hydrophobic precipitated silica. The method comprises contacting an aqueous suspension of a hydrophilic precipitated silica with (1) a catalytic amount of an acid and (2) an organosilicon compound in the presence of (3) a water-miscible organic solvent in an amount sufficient to facilitate reaction of the hydrophilic precipitated silica with the organosilicon compound to form a hydrophobic precipitated silica.
摘要:
Cured tread rubber compositions of tires contain cured organic rubber, from 0 to 20 phr of reinforcing carbon black, and from 40 to 120 phr of reinforcing reinforced amorphous precipitated silica wherein the silica has a surface area of from 160 to 340 m.sup.2 /g and a pore diameter at the maximum of the volume pore size distribution function of from 5 to 19 nm. The presence of such reinforcing silica provides improved tire performance characteristics, especially improved paved highway performance, to tires having treads of the cured tread rubber compositions.
摘要:
Precipitated amorphous silica useful for manufacturing microporous battery separators is prepared by establishing an aqueous solution of alkali metal silicate having an alkali metal oxide concentration of (a) from 2.1-2.6 grams per liter and a temperature of from about 179.degree. F. to 186.degree. F., or (b) from 5.6 to 7.2 grams per liter and a temperature of from 190.degree. to 198.degree. F.; adding from (a) 14.5 to 19 times or (b) 2 to 5 times respectively the amount of alkali metal silicate initially present in the initial aqueous solution simultaneously with acidifying agent, e.g., sulfuric acid, to the initial aqueous solution while maintaining the initial alkali metal oxide concentration therein substantially constant; reducing the pH of the resulting slurry to from 8 to 9; ageing the slurry at precipitation temperatures for from 15 to 90 minutes; reducing the pH of the aged slurry to from 3.8 to 4.7 and then recovering, e.g., separating, the silica from its entraining slurry, washing the recovered silica, and drying the washed precipitated silica. Optionally, the recovered and dried silica is milled after drying to produce a product having a median agglomerate particle size of from 6 to 15 micrometers.
摘要:
Amorphous precipitated high structure silica pigment useful in the reinforcement of silicone rubber is described. The silica pigment is treated with an aqueous solution of a metal, e.g., calcium and barium, which forms a relatively water insoluble, white or colorless sulfate salt in amounts sufficient to provide at least an equal molar amount of the metal compared to the amount of alkali metal in the silica. Silicone rubber reinforced with such silica pigment exhibits a water swell of less than 4 volume percent.
摘要:
Amorphous precipitated silica which may be used to form battery separators of very low shrinkage is characterized by (a) a BET surface area in the range of from 60 to 200 m.sup.2 /g; (b) a CTAB surface area in the range of from 40 to 150 m.sup.2 /g; (c) a DBP oil absorption in the range of from 180 to 300 cm.sup.3 /100 g; (d) a mean ultimate particle size in the range of from 20 to 30 nm; (e) a total intruded volume in the range of from 2.5 to 4 cm.sup.3 /g; (f) an intruded volume in the range of from 0.3 to 1.2 cm.sup.3 /g for pores having diameters in the range of from 20 to 100 nm; and (g) a pore diameter at the maximum of the volume pore size distribution function in the range of from 30 to 200 nm.
摘要:
Cured tread rubber compositions of tires contain cured organic rubber, from 40 to 150 phr of reinforcing carbon black, and reinforcing reinforced amorphous precipitated silica wherein the silica has a surface area of from 160 to 340 m.sup.2 /g and a pore diameter at the maximum of the volume pore size distribution function of from 5 to 19 nm. The presence of such reinforcing silica provides improved tire performance characteristics, especially improved paved highway performance, to tires having treads of the cured tread rubber compositions.
摘要:
Free flowing, substantially dust-free, dense granular amorphous precipitated silica having a principal particle size of between about 0.14 millimeters and about 0.84 millimeters are described. This material is particularly suitable as an inert carrier for water-soluble and fat soluble nutritional supplements, e.g., vitamins, which are added to feeds for livestock.