Abstract: Treating compositions for application to particles of a filler consist of 5-95 percent by weight of a silicon atom containing hydrophobic-type treating agent, and 5-95 percent by weight of a silicon atom containing functional-type treating agent, based on the weight of the composition. Useful functional-type treating agents include bis(alkoxysilylalkyl)polysulfides and mercaptoorganosilicon compounds. Useful hydrophobic-type treating agents include polyorganohydrogensiloxanes and silanol terminated silicone oligomers. The filler most preferred is precipitated (i.e., synthetic) calcium carbonate.

Abstract: Treating compositions for application to particles of a filler consist of 5-95 percent by weight of a silicon atom containing hydrophobic-type treating agent, and 5-95 percent by weight of a silicon atom containing functional-type treating agent, based on the weight of the composition. Useful functional-type treating agents include bis(alkoxysilylalkyl)polysulfides and mercaptoorganosilicon compounds. Useful hydrophobic-type treating agents include polyorganohydrogensiloxanes and silanol terminated silicone oligomers. The filler most preferred is precipitated (i.e., synthetic) calcium carbonate.

Abstract: This invention is a process for making modified silica filler comprising the steps of: (A) contacting an acidic aqueous suspension of precipitated or colloidal silica, optionally in the presence of a surfactant and/or a water-miscible solvent, with a combination of (a) a functionalizing coupling agent, and (b) an organometallic hydrophobing compound in a weight ratio of (a) to (b) of at least 0.001 to 1 to form an acidic aqueous suspension of chemically treated silica filler having a pH of 2.0 or less (B) treating the acidic aqueous suspension of the chemically treated filler with an acid-neutralizing agent to increase the pH of the suspension to a range of from greater than 2.0 to 10, and (C) recovering the chemically treated filler. This invention is also modified silica filler that has a pH of from about 5.0 to 10.0, where the silica filler is made by the method of this invention.

Abstract: 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.

Abstract: The present invention is neutral-aged hydrophobic silica gels having a reduced surface area and a method for their preparation. The method comprises three steps, where in the first step a mixture comprising a silica hydrosol and colloidal silica is contacted with a strong mineral acid at a pH less than about 1 to form a silica hydrogel having incorporated therein colloidal silica. In the second step the silica hydrogel is aged at a pH within a range of about pH 3.5 to pH 8. In the third step the silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel to form a hydrophobic silica hydrogel having a surface area within a range of about 100 m.sup.2 /g to 450 m.sup.2 /g in the dry state. In a preferred method the hydrophobic silica hydrogel and is further contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.

Abstract: The present invention is hydrophobic silica gels having a reduced surface area and a method for their preparation under neutral conditions. The method comprises two steps, where in the first step the pH of a mixture comprising a silica hydrosol and colloidal silica is adjusted with a base to within a range of pH 3 to pH 6 to facilitate formation of a silica hydrogel having incorporated therein colloidal silica. In the second step the silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel to form a hydrophobic silica gel having a surface area within a range of about 100 m.sup.2 /g to 450 m.sup.2 /g in the dry state. In a preferred process the hydrophobic silica gel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.

Abstract: The present invention is neutral-aged hydrophobic organosilicate-modified silica gels and a method for their preparation. The method comprises three steps, where in the first step an organosilicate-modified silica hydrosol is contacted with a strong mineral acid at a pH less than about 1 to form an organosilicate-modified silica hydrogel. In the second step the organosilicate-modified silica hydrogel is aged at a pH within a range of about pH 3.5 to pH 8. In the third step the neutral-aged organosilicate-modified silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the organosilicate-modified silica hydrogel to form a hydrophobic organosilicate-modified silica hydrogel having a surface area within a range of about 100 m.sup.2 /g to 750 m.sup.2 /g in the dry state.

Abstract: The present invention is hydrophobic organosilicate-modified silica gels and a method for their preparation under neutral conditions. The method comprises two steps, where in the first step the pH of an organosilicate-modified silica hydrosol is adjusted with a base to within a range of about pH 3 to pH 7 to facilitate formation of an organosilicate-modified silica hydrogel. In the second step the organosilicate-modified silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the organosilicate-modified silica hydrogel to form a hydrophobic organosilicate-modified silica gel having a surface area within a range of about 100 m.sup.2 /g to 850 m.sup.2 /g in the dry state.

Abstract: A method for the preparation of hydrophobic silica gels which are useful as reinforcing fillers in rubber compositions. The method comprises two steps, where in the first step a silica hydrosol is contacted with a sufficient concentration of a strong mineral acid at a pH less than about pH 1 to form a silica hydrogel. In the second step the silica hydrogel is contacted with described organosilicon compounds in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel thereby forming a hydrophobic silica gel having a surface area within a range of about 100 m.sup.2 /g to 750 m.sup.2 /g as measured in the dry state. In a preferred method the hydrophobic silica hydrogel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.

Abstract: The present invention is hydrophobic organosilicate-modified silica gels and a method for their preparation. The method comprises two steps, where in the first step an organosilicate-modified silica hydrosol is heat treated in the presence of a strong mineral acid at a pH less than about pH 1 to form an organosilicate-modified silica hydrogel. In the second step the organosilicate-modified silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the organosilicate-modified silica hydrogel thereby forming a hydrophobic organosilicate-modified silica hydrogel having a surface area within a range of about 100 m.sup.2 /g to 750 m.sup.2 /g as measured in the dry state.

Abstract: The present invention is hydrophobic silica gels and a method for their preparation under neutral conditions. The method comprises two steps, where in the first step the pH of a silica hydrosol is adjusted with a base to within a range of about pH 3 to pH 7 to facilitate formation of a silica hydrogel. In the second step the silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel. In a preferred method, in a third step the hydrophobic silica gel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.