| 摘要 |
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 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 100M2/G TO 750M2/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.
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