US4251281A
Expired / Lapsed
US
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Synthetic amorphous silica for elastomeric reinforcement and methods therefor
Assignee: Rhone Poulenc Industries SA
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Filing: 1979-05-01
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Granted: 1981-02-17
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Expires: 1999-05-01
Abstract
Abstract A synthetic amorphous silica having a CTAB surface area of from about 80 to about 125 m 2 /g and a structure index of at least 0.80 is disclosed as adapted for the reinforcement of elastomeric materials, as well as methods for the preparation thereof.
Inventors
- 👤 Jean Machurat
- 👤 Jean-Claude Morawski
- 👤 Georges Vrisakis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:42
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/18; C01B33/187; C01B33/193; C08; C08K; C08K3/00; C08K3/34; C08K3/36; C01P; C01P2002/00; C01P2002/02; C01P2006/00; C01P2006/12; C01P2006/19; C01P2006/80; C01P2006/82; C01P2006/90
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
98 words
A synthetic amorphous silica adapted for the reinforcement of elastomeric materials and having a reinforcement-effective structure, comprising particulates having a CTAB surface area of from about 80 to about 125 m 2 /g, a structure index of at least about 0.80, an oil absorption index (DBP) of from about 240 to about 320 cm 3 /100 g, a BET surface area of from about 80 to about 310 m 2 /g and wherein the ratio of BET area to CTAB area is at least about 1.1, and a wet cake moisture content of from about 75 to 82%.
Claim 2
Dependent Claim
98 words
A synthetic amorphous silica adapted for the reinforcement of elastomeric materials and having a reinforcement-effective structure, comprising particulates having a CTAB surface area of from about 80 to about 125 m 2 /g, a structure index of at least about 0.80, an oil absorption index (DBP) of from about 240 to about 320 cm 3 /100 g, a BET surface area of from about 80 to about 310 m 2 /g and wherein the ratio of BET area to CTAB area is at least about 1.1, and a wet cake moisture content of from about 75 to 82%.
Claim 3
Dependent Claim
12 words
The synthetic amorphous silica as defined by claim 1, in dried state.
Claim 4
Dependent Claim
26 words
A composition of matter comprising an elastomeric material, said elastomeric material having homogeneously dispersed therein a reinforcing amount of the particulates as defined by claim 2.
Claim 5
Independent Claim
211 words
A method for producing a synthetic amorphous silica adapted for the reinforcement of elastomeric materials and having a reinforcement-effective structure, said method comprising the steps of: (a) reacting a strong acid with an alkaline silicate solution having an initial SiO 2 /Na 2 O molar ratio of from about 2 to about 4, and an initial silicate concentration of from about 90 to about 150 g/l SiO 2 ; (b) maintaining essentially constant the residual alkalinity of the reaction mixture during the reaction by adding said strong acid at a variable rate to the reaction mixture; (c) adjusting said molar ratio to about 3.5 to effect a final silicate concentration of from about 60 to about 90 g/l SiO 2 ; and, (d) adjusting the reaction temperature within the range of about 65° to about 95° C. to yield a silica product having a wet cake moisture of from about 75 to about 82%, corresponding to from about 2.6 to about 3.9 kg of water per kg of finished product; to yield an amorphous silica particulate having a CTAB surface area of from about 80 to about 125 m 2 /g and a structure index of at least 0.80 in a total reaction time of from about 40 to 200 minutes.
Claim 6
Independent Claim
211 words
A method for producing a synthetic amorphous silica adapted for the reinforcement of elastomeric materials and having a reinforcement-effective structure, said method comprising the steps of: (a) reacting a strong acid with an alkaline silicate solution having an initial SiO 2 /Na 2 O molar ratio of from about 2 to about 4, and an initial silicate concentration of from about 90 to about 150 g/l SiO 2 ; (b) maintaining essentially constant the residual alkalinity of the reaction mixture during the reaction by adding said strong acid at a variable rate to the reaction mixture; (c) adjusting said molar ratio to about 3.5 to effect a final silicate concentration of from about 60 to about 90 g/l SiO 2 ; and, (d) adjusting the reaction temperature within the range of about 65° to about 95° C. to yield a silica product having a wet cake moisture of from about 75 to about 82%, corresponding to from about 2.6 to about 3.9 kg of water per kg of finished product; to yield an amorphous silica particulate having a CTAB surface area of from about 80 to about 125 m 2 /g and a structure index of at least 0.80 in a total reaction time of from about 40 to 200 minutes.
Claim 7
Dependent Claim
31 words
The method of claim 4, wherein the acid additions are interrupted at least once during a period of from about 5 to about 20 minutes when maximum polymer formation is achieved.
Claim 8
Dependent Claim
21 words
The method of claim 5, wherein said total reaction time, excluding said interruptions, is from about 40 to about 200 minutes.
Claim 9
Dependent Claim
39 words
The method of claim 4, wherein said step of maintaining essentially constant said residual alkalinity comprises the step of periodically introducing fractions of said acid to the reaction mixture at intervals not exceeding about 10 minutes between successive additions.
Claim 10
Dependent Claim
37 words
A vulcanized elastomeric composition having homogeneously dispersed therein and firmly adhered thereto, a reinforcing amount of particulates of the synthetic amorphous silica as defined by claim 2, said vulcanizate having a percentage dispersion of at least 90%.
Claim 11
Dependent Claim
37 words
A vulcanized elastomeric composition having homogeneously dispersed therein and firmly adhered thereto, a reinforcing amount of particulates of the synthetic amorphous silica as defined by claim 2, said vulcanizate having a percentage dispersion of at least 95%.
Claim 12
Dependent Claim
37 words
A vulcanized elastomeric composition having homogeneously dispersed therein and firmly adhered thereto, a reinforcing amount of particulates of the synthetic amorphous silica as defined by claim 2, said vulcanizate having a percentage dispersion of at least 98%.
Claim 13
Dependent Claim
12 words
A tire comprising the vulcanized elastomeric composition as defined by claim 8.
Claim 14
Dependent Claim
12 words
A tire comprising the vulcanized elastomeric composition as defined by claim 9.
Claim 15
Dependent Claim
12 words
A tire comprising the vulcanized elastomeric composition as defined by claim 10.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-17 | 1984-08-18 | 1985-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-17 | 1988-08-18 | 1989-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-17 | 1992-08-18 | 1993-02-17 | $7700.00 | Window Closed / Lapsed |