Rhodia Chimie

Rhone-poulenc Chimie

Compagnie Générale Des Etablissements Michelin-Michelin & Cie

Yves Bomal

Yvonick Chevallier

Evelyne Prat

Philippe Cochet

Gerard Mignani

Olivier Durel

Jean-Manuel Mas

Philippe Karrer

Christian Priou

Nathalie Guennouni

Anny Guez

Pierre Barruel

Antoine Guiu

G&eacute;rard Velleret

The invention relates to the use of a silica having a BET specific surface of at least 60 m/g for increasing the rigidity of a thermoplastic polymeric material while maintaining i.e. improving its impact resistance. The silica used is of the type obtained according to a method involving the drying of a silica suspension obtained by reacting a silicate with an acidulant according to the following successive steps: (i) forming an aqueous starter having a pH between 2 and 5; (ii) simultaneously adding silicate and the acidulant while keeping the pH between 2 and 5; (iii) continuing with only the addition of silicate until a pH between 7 and 10 has been reached; (iv) simultaneously adding silicate and acidulant while keeping the pH of the reaction medium between 7 and 10, and; (v) continuing with only the addition of the acidulant until a pH value lower than 6 has been obtained. The invention also relates to the materials obtained within this scope.

Use of specific silicas for increasing the rigidity of a thermoplastic while maintaining or improving its impact resistance

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

Rubber composition intended for the manufacture of tire casings which have improved hysteretic properties and scorch safety, based on at least one elastomer and silica by way of reinforcing filler enclosing a reinforcing additive consisting of the mixture and/or the product of in situ reaction of at least one functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically to the surface hydroxyl sites of the silica particles and at least one functionalized organosilane compound containing, per molecule, at least one functional group capable of bonding chemically and/or physically to the polyorganosiloxane and/or the hydroxyl sites of the silica particles and at least one other functional group capable of bonding chemically and/or physically to the polymer chains.

Rubber composition for tire casings based on silicas containing a reinforcing additive based on a functionalized polyorganosiloxane and on an organosilane compound

The present invention relates to a process for preparing multifunctionalized polyorganosiloxanes (POSs) comprising alkoxyl functional siloxyl units and siloxyl units each having an SH functional group, which consists in introducing the SH functional group by the reaction of H S on a precursor POS of formula: A&mdash;(RXSiO) &mdash;(RYSiO) &mdash;B where R is especially a C -C alkyl radical, X is a C -C alkoxyl radical, Y is a C -C hydrocarbon group which includes an ethylenically unsaturated group from which the SH functionality derives, a is a number ranging from 1 to 150, b is a number ranging from 1 to 150, the number a&plus;b ranging from 2 to 300 and A and B are terminal groups which are selected respectively, from, in particular, on the one hand (R) SiO&mdash; radicals taken alone or as mixtures with (R) XSiO&mdash; and/or R(X) SiO&mdash; and/or (X) SiO&mdash; radicals and on the other hand &mdash;Si(R) radicals taken alone or as mixtures with &mdash;SiX(R) and/or &mdash;Si(X) R and/or &mdash;Si(X) radicals.

Method for preparing polyorganosiloxanes (POS) with thiol functions, POS obtainable by this method and their use particularly in rubber materials

Particles treated with a functionalized polyorganosiloxane

Use of a combination of silicone compounds as a coupling agent in silica-loaded elastomer compositions

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

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.

Process for the preparation of precipitated silica, new precipitated

Rubber composition intended for the manufacture of tire casings which have mproved hysteretic properties and scorch safety, based on at least one elastomer and silica by way of reinforcing filler enclosing a reinforcing additive consisting of the mixture and/or the product of in situ reaction of at least one functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically to the surface hydroxyl sites of the silica particles and at least one functionalized organosilane compound containing, per molecule, at least one functional group capable of bonding chemically and/or physically to the polyorganosiloxane and/or the hydroxyl sites of the silica particles and at least one other functional group capable of bonding chemically and/or physically to the polymer chains.

Rubber composition for tire casings based on silicas containing a

The present invention relates to compounds composed essentially of a linear, cyclic or branched polyorganosiloxane having, per molecule, at least 3 siloxy units, including at least one siloxy functional unit of formula: ##STR1## where R.sup.1 represents a C.sub.1 to C.sub.4 alkyl or phenyl radical, X contains an N,N'-di- and/or trisubstituted phenylenediamine functional group, bonded to the silicon via an Si-(hydrocarbon linking unit)-N and/or Si-(hydrocarbon linking unit)-C bond, and a is a number chosen from 0, 1 and 2. The present invention also relates to the use of such compounds as antiozonants for rubbers and in particular for rubber compositions for tires.

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Paris, France

Yves Bomal