# US 11,111,360 B2 · Rubber composition comprising at least one silica as inorganic reinforcing filler

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- Number: US 11,111,360 B2
- Document ID: US11111360B2
- Status: Granted
- Kind: B2
- Application number: 16/610,685
- Filed: 2018-05-03
- Published: 2020-05-28
- Granted: 2021-09-07
- Earliest claimed: 2017-05-05
- Assignees: Compagnie Generale Des Etablissements Michelin
- Applicants: Compagnie Generale Des Etablissements Michelin
- Inventors: Angélique Pawlak; Emmanuelle Allain Najman; Stéphane Badaire; Caroline Fayolle; Pascaline Garbey; Laurent Guy; Sylvaine Neveu; Fabien Stocklouser
- Web page: https://patentgrep.com/patent/US11111360B2

## CPC

- C08L 9/06: Copolymers with styrene
- B60C 1/00: Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
- B60C 1/0016: {Compositions of the tread}
- C01B 33/12: Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C08K 3/04: Carbon
- C08K 3/06: Sulfur
- C08K 3/22: of metals
- C08K 3/36: Silica
- C08K 5/09: Carboxylic acids; Metal salts thereof; Anhydrides thereof
- C08K 5/18: with aromatically bound amino groups
- C08K 5/31: Guanidine; Derivatives thereof
- C08K 5/47: Thiazoles
- C08K 5/548: containing sulfur {(C08K5/5477 takes precedence)}
- C08L 7/00: Compositions of natural rubber
- C08L 15/00: Compositions of rubber derivatives (C08L11/00, C08L13/00 take precedence)
- C08L 57/02: Copolymers of mineral oil hydrocarbons
- C08K 2003/2296: {of zinc}
- C08K 2201/003: Additives being defined by their diameter
- C08K 2201/006: Additives being defined by their surface area
- C08K 2201/016: Additives defined by their aspect ratio
- C08L 2205/02: containing two or more polymers of the same C08L -group
- C08L 2312/00: Crosslinking
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A rubber composition is based on at least one elastomer, a reinforcing inorganic filler, an agent for coupling the elastomer to the reinforcing inorganic filler, and a crosslinking system. The reinforcing inorganic filler comprises at least one silica S having: a CTAB specific surface area SCTAB within a range extending from 40 to 300 m2/g; a difference between the BET specific surface area SBET and the CTAB specific surface area SCTAB of greater than or equal to 35 m2/g; an aluminium content WAl within a range extending from 0.5 to 7.0% by weight relative to the weight of the silica S; a width of the aggregate size distribution Ld, measured by centrifugal sedimentation, of greater than or equal to 1.5; and a median aggregate diameter d50, measured by centrifugal sedimentation, such that for a given value of CTAB specific surface area SCTAB and a given aluminium content WAl, a magnitude A is defined by the following equation (I): A=[d50]+0.782×[SCTAB]−8.524×[WAl] (I), in which: [d50] is the numerical value of d50, expressed in nm; [SCTAB] is the numerical value of SCTAB, expressed in m2/g; [WAl] is the numerical value of WAl, expressed in % by weight relative to the weight of the silica S; and said magnitude A satisfies the relationship (II): A≥253 (II). The compositions of the invention are of use in tyres or semi-finished articles for tyres.

## Claims

### Claim 1

A rubber composition based on at least one elastomer, a reinforcing inorganic filler, an agent for coupling the elastomer to the reinforcing inorganic filler, and a crosslinking system, wherein the reinforcing inorganic filler comprises at least one silica S having:
a CTAB specific surface area SCTAB within a range extending from 40 to 300 m2/g;
a difference between a BET specific surface area SBET and the CTAB specific surface area SCTAB of greater than or equal to 35 m2/g;
an aluminium content WAl within a range extending from 0.5 to 7.0% by weight relative to a weight of the silica S;
a width of the aggregate size distribution Ld, measured by centrifugal sedimentation, of greater than or equal to 1.5; and
a median aggregate diameter d50, measured by centrifugal sedimentation, such that for a given value of CTAB specific surface area SCTAB and a given aluminium content WAl, a magnitude A is defined by the following equation (I):
A=[d50]+0.782×[SCTAB]−8.524×[WAl] (I)
in which:
[d50] is the numerical value of d50, expressed in nm;
[SCTAB] is the numerical value of SCTAB, expressed in m2/g;
[WAl] is the numerical value of WAl, expressed in % by weight relative to the weight of the silica S; and
the magnitude A satisfies the relationship (II):
A≥253 (II), and
wherein the content of reinforcing inorganic filler is within a range extending from 80 to 150 phr.

### Claim 2 (depends on 1)

The rubber composition according to claim 1, wherein the relationship (II) is 259≤A≤300 (IIf).

### Claim 3 (depends on 1)

The rubber composition according to claim 1, wherein the aluminium content WAl of the silica S is within a range extending from 0.5 to 5.0% by weight relative to the weight of the silica S.

### Claim 4 (depends on 1)

The rubber composition according to claim 1, wherein the width of the aggregate size distribution Ld, measured by centrifugal sedimentation, of the silica S is within a range extending from 1.5 to 3.5.

### Claim 5 (depends on 1)

The rubber composition according to claim 1, wherein the difference between the BET specific surface area SBET and the CTAB specific surface area SCTAB of the silica S is greater than or equal to 40 m2/g.

### Claim 6 (depends on 1)

The rubber composition according to claim 1, wherein the CTAB specific surface area SCTAB of the silica S is within a range extending from 110 to 300 m2/g.

### Claim 7 (depends on 1)

The rubber composition according to claim 1, wherein the silica S has a BET specific surface area SBET of greater than or equal to 160 m2/g.

### Claim 8 (depends on 1)

The rubber composition according to claim 1, wherein the reinforcing inorganic filler further comprises an additional silica other than the silica S.

### Claim 9 (depends on 1)

The rubber composition according to claim 1, wherein the silica S represents at least 50% by weight of the total weight of the reinforcing inorganic filler.

### Claim 10 (depends on 1)

The rubber composition according to claim 1, wherein the silica S represents 100% by weight of the total weight of the reinforcing inorganic filler.

### Claim 11 (depends on 1)

The rubber composition according to claim 1 further comprising a reinforcing organic filler which is carbon black.

### Claim 12 (depends on 1)

The rubber composition according to claim 1, wherein the elastomer is a diene elastomer.

### Claim 13 (depends on 12)

The rubber composition according to claim 12, wherein the diene elastomer is selected from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers and mixtures thereof.

### Claim 14 (depends on 12)

The rubber composition according to claim 12, wherein the diene elastomer is selected from the group consisting of polybutadienes, butadiene/styrene copolymers, isoprene/butadiene copolymers, isoprene/styrene copolymers, isoprene/butadiene/styrene copolymers and mixtures thereof.

### Claim 15 (depends on 12)

The rubber composition according to claim 12, wherein the elastomer is a functionalized diene elastomer.

### Claim 16 (depends on 1)

A semi-finished article comprising at least one composition according to claim 1.

### Claim 17 (depends on 16)

The semi-finished article according to claim 16, wherein the semi-finished article is a tire tread.

### Claim 18 (depends on 1)

A tire comprising at least one composition according to claim 1.

### Claim 19

A process for preparing a rubber composition based on at least one elastomer, a reinforcing inorganic filler, an agent for coupling the elastomer to the reinforcing inorganic filler, and a crosslinking system, the process comprising the following steps:
contacting the at least one elastomer, the at least one reinforcing inorganic filler, and the at least one agent for coupling the elastomer to the reinforcing inorganic filler to make a mixture, wherein the content of reinforcing inorganic filler is within a range extending from 80 to 150 phr,
wherein the reinforcing inorganic filler comprises at least one silica S having:
a CTAB specific surface area SCTAB within a range extending from 40 to 300 m2/g;
a difference between a BET specific surface area SBET and the CTAB specific surface area SCTAB of greater than or equal to 35 m2/g;
an aluminium content WAl within a range extending from 0.5 to 7.0% by weight relative to a weight of the silica S;
a width of the aggregate size distribution Ld, measured by centrifugal sedimentation, of greater than or equal to 1.5; and
a median aggregate diameter d50, measured by centrifugal sedimentation, such that for a given value of CTAB specific surface area SCTAB and a given aluminium content WAl, a magnitude A is defined by the following equation (I):
A=[d50]+0.782×[SCTAB]−8.524×[WAl] (I)
in which:
[d50] is the numerical value of d50, expressed in nm;
[SCTAB] is the numerical value of SCTAB, expressed in m2/g;
[WAl] is the numerical value of WAl, expressed in % by weight relative to the weight of the silica S; and
the magnitude A satisfies the relationship (II):
A≥253 (II);
thermomechanically kneading the mixture, once or several times, until a maximum temperature of between 110° C. and 190° C. is reached;
cooling the mixture from the preceding step to a temperature below 100° C.;
incorporating a crosslinking system into the cooled mixture from the preceding step; and
kneading the mixture comprising the crosslinking system up to a maximum temperature below 110° C.