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Compagnie Generale Des Establissements Michelin - Michelin & Cie

Yvonick Chevallier

Evelyne Prat

Yves Bomal

Philippe Cochet

Adrien Dromard

Jean-Claude Morawski

Michel Rabeyrin

Pierre-Yves Lahary

Jean Berthoux

Rémi Valero

Jacques-Pierre Martinaud

Remi Valero

Dominique Petit

Francois Meiller

Jean-Marie Micouin

Patrick Lamy

Jacques Billion

Céline Marcandelli

Fr&egrave;d&egrave;ric Amiche

Patrick Fourre

Francis Bomo

Precipitated silica specifically useful in the paper industry and in particular in paper-coating applications for inject printing, is characterized by an uptake of DOP oil lower than 260 ml/100 g, a pore volume (V) of greater than 0.8 ml/g formed by pores having a diameter of less than 25 nm, a CTAB specific surface area of greater than 280 m/g.

Precipitated silica and paper industry/other applications thereof

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.

Highly-structured silica having a low water uptake, preparation method thereof and uses of same

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 SiOequivalent, 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 SiOequivalent, 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.

Low water uptake silicas

The invention concerns the use, as thickening or texturing agent in toothpaste compositions, of a highly dispersible precipitated silica having a pH of 3.5 to 9, a DOP oil absorption higher than 200 ml/g, a CTAB specific surface area from 70 to 250 m2, a median diameter of at least 20 &#x3bc;m determined by ultrasound-free laser diffraction, a residual anion rate, expressed in sodium sulphate, less than 5 wt. %.

Use of a high structure and dispersible precipitated silica as a thickening or texturing agent in toothpaste compositions

The invention relates to a new process for the preparation of precipitated silica which has an excellent dispersibility and very satisfactory reinforcing properties. It also relates to new precipitated silicas which are in the form of powder, of substantially spherical beads or of granules, these silicas being characterized by the fact that they have a CTAB specific surface of between 140 and 200 m /g, a BET specific surface of between 140 and 200 m /g, a DOP oil uptake lower than 300 ml/100 g, a median diameter, after disintegration with ultrasound, smaller than 3 &mgr;m, an ultrasonic disintegration factor higher than 10 ml and an aluminum content of at least 0.35% by weight. The invention also relates to the use of the said silicas as reinforcing fillers for elastomers.

Process for the preparation of precipitated silica, new precipitated silicas containing aluminum and their use for the reinforcement of elastomers

Process for preparation of abrasive precipitated silica

The invention relates to a novel process for the preparation of precipitated silica which can be used as a reinforcing filler for elastomers. The invention also relates to novel precipitated silicas in the form of powder, granules or, preferably, substantially spherical beads, these silicas being characterized in that they have a BET specific surface of between 185 and 250 m /g, a CTAB specific surface of between 180 and 240 m /g, and a pore distribution such that the pore volume V2 made up of the pores with a diameter of between 175 and 275 &angst; represents less than 50% of the pore volume V1 made up of the pores with diameters of less than or equal to 400 &angst;, a pore volume (V ), made up of the pores with a diameter of less than 1 &mgr;m, of greater than 1.65 cm /g, a fineness value (F.V.) of between 70 and 100 &angst;, and a content of fines (&tgr; ), after deagglomerability with ultrasound, of at least 50%.

Precipitated silica used as reinforcing filler for elastomers

Silicas in the form of powder and substantially spherical beads or granules are characterized by a CTAB specific surface of 140 and 240 m /g a high ultrasonic disaggregation factor, an average diameter, which is small after ultrasonic disaggregation, and optionally, a porous distribution, the porous volume formed by the pores with a diameter of 175 to 275 &angst; being less than 50% of the porous volume formed by the pores with diameters of 400 &angst; or less. The silicas may be used as reinforcing fillers for elastomers. The invention also concerns a method for preparing precipitated silica of the type comprising the reaction of an alkaline metal silicate M with an acidifying agent, resulting in a suspension of precipitated silica, and the separation and drying of said suspension, wherein precipitation is performed as follows: (i) an initial seed is formed comprising a portion of the total quantity of alkaline metal silicate M in the reaction, the silicate concentration (expressed as SiO ) in said seed being less than 20 g/l; (ii) an acidifying agent is added to the initial seed until at least 5% of the quantity of M O in the initial seed is neutralized; (iii) the acidifying agent and the remaining quantity of alkaline metal silicate M are added simultaneously so that the ratio of the quantity of added silicate (expressed as SiO ) to the quantity of silica in the initial seed (expressed as SiO ) is greater than 4 and at most 100.

Precipitated silica

Essentially spherical precipitated silica beads, well adapted for the reinforcement of elastomeric matrices, have a mean particle size of at least 80 &mgr;m, a BET specific surface area ranging from 60 to 130 m,/g, a fill density in packed state ranging from 0.28 to 0.37, and a total pore volume ranging from 1.6 to 3.3 cm,/g.

Precipitated silica beads

The invention relates to a new process for the preparation of precipitated silica which has a very good dispersibility and very satisfactory reinforcing properties. It also relates to new precipitated silicas which are in the form of powder, of substantially spherical beads or of granules, these silicas being characterized by the fact that they have a CTAB specific surface of between 100 and 240 m,/g, a DOP oil uptake lower than 300 ml/100 g, a pore distribution such that the pore volume consisting of the pores whose diameter is between 175 and 275 &angst; represents less than 50% of the pore volume consisting of the pores of diameters which are smaller than or equal to 400 &angst;, a median diameter, after disintegration with ultrasound, smaller than 5 &mgr;m and an aluminum content of at least 0.35% by weight. The invention also relates to the use of the said silicas as reinforcing fillers for elastomers.

Process for the preparation of precipitated silica, new precipitated silicas containing aluminium and their use for the reinforcement of elastomers

A mechanically strong, vulcanized elastomeric matrix having an effective amount of a reinforcing filler material homogeneously dispersed and distributed therethrough, the reinforcing filler material comprising finely divided precipitated silica particulates and the precipitated silica particulates deriving from a powder having a CTAB specific surface ranging from 100 to 140 m,/g, a median diameter &phgr;,, after ultrasonic disintegration, less than 2.8 &mgr;m, exhibiting an ultrasonic disintegration factor F,greater than 3 ml, having a BET specific surface ranging from 100 to 200 m,/g, having a mean particle size greater than 15 &mgr;m, a packing density in the tamped state of at least 0.17, and a DOP oil uptake ranging from 150 to 400 ml/100 g.

Elastomeric matrix reinforced with precipitated silicas

The present invention relates to a rubber composition intended for the manufacture of road tires of improved resistance to rolling having a base of precipitated silica with a relatively high specific surface and special porosity properties.

Silica-Base rubber composition intended for the manufacture of highway tires improved resistance to rolling

Silicas in the form of powder and substantially spherical beads or granules are characterized by a CTAB specific surface of 140 and 240 m,/g a high ultrasonic disaggregation factor, an average diameter, which is small after ultrasonic disaggregation, and optionally, a porous distribution, the porous volume formed by the pores with a diameter of 175 to 275 &angst; being less than 50% of the porous volume formed by the pores with diameters of 400 &angst; or less. The silicas may be used as reinforcing fillers for elastomers. The invention also concerns a method for preparing precipitated silica of the type comprising the reaction of an alkaline metal silicate M with an acidifying agent, resulting in a suspension of precipitated silica, and the separation and drying of said suspension, wherein precipitation is performed as follows: (i) an initial seed is formed comprising a portion of the total quantity of alkaline metal silicate M in the reaction, the silicate concentration (expressed as SiO,) in said seed being less than 20 g/l; (ii) an acidifying agent is added to the initial seed until at least 5% of the quantity of M,O in the initial seed is neutralized; (iii) the acidifying agent and the remaining quantity of alkaline metal silicate M are added simultaneously so that the ratio of the quantity of added silicate (expressed as SiO,) to the quantity of silica in the initial seed (expressed as SiO,) is greater than 4 and at most 100.

The invention relates to a new process for the preparation of precipitated silica which has a good dispersibility and very satisfactory reinforcing properties. It also relates to new precipitated silicas which are in the form of powder, of substantially spherical beads or of granules, these silicas being characterized by the fact that they have a CTAB specific surface of between 90 and 250 m.sup.2 /g, a BET specific surface of between 90 and 250 m.sup.2 /g, a DOP oil uptake lower than 300 ml/100 g, a zinc content of between 1 and 5% by weight, and by the fact that the number N of stearic acid molecules consumed per nm.sup.2 of silica surface, when stearic acid is reacted with this silica in xylene for 2 hours at 120.degree. C., is at least 1. The invention also relates to the use of the said silicas as reinforcing fillers for elastomers, especially for improving their rheological properties.

Process for the precipitated silica new precipitated silicas containing

The invention relates to a new process for the preparation of precipitated silica which has a good dispersibility and very satisfactory reinforcing properties. It also relates to new precipitated silicas which are in the form of powder, of substantially spherical beads or of granules, these silicas being characterized by the fact that they have a CTAB specific surface of between 90 and 250 m.sup.2 /g, a DOP oil uptake lower than 300 ml/100 g, a pore distribution such that the pore volume consisting of the pores whose diameter is between 175 and 275 .ANG. represents less than 50% of the pore volume consisting of the pores of diameters smaller than or equal to 400 .ANG., a zinc content of between 1 and 5% by weight and by the fact that the number N of molecules of stearic acid consumed per nm.sup.2 of silica surface, when stearic acid is reacted with the said silica in xylene for 2 hours at 120.degree. C., is at least 1. The invention also relates to the use of the said silicas as reinforcing fillers for elastomers especially for improving their rheological properties.

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Speracedes, France

Yvonick Chevallier