Patent US4781940A successfully refreshed from Google Patents.
US4781940A
Expired / Lapsed
US
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Method for producing filler for microfilled dental composite material
Assignee: Johnson and Johnson Dental Products Co
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Filing: 1987-06-26
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Granted: 1988-11-01
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Expires: 2007-06-26
Abstract
Abstract A filler for use in dental composites is made by the following process: (a) finely divided silica, such as fumed silica, is coated with a polymerizable monomeric material by (e.g., an acrylic monomer) by mixing the silica with an organic solvent solution of the monomer; (b) the solvent is removed by evaporation by any convenient means; (c) the coated silica particles are individualized, as by screening, to produce a powder of a predetermined particle size (e.g., 90 microns or smaller); and (d) the resin is then polymerized. Some individualization of the product of step (d) may be required. Light screening is usually sufficient.
Inventors
- 👤 Robert K. Denton, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:50
CPC Classifications
C; C08; C08F; C08F2/00; C08F2/44; A; A61; A61K; A61K6/00; A61K6/15; A61K6/17; A61K6/70; A61K6/71; A61K6/76; A61K6/77; A61K6/78; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
92 words
A process for the production of a filler for use in a microfilled dental composite formulation, which process comprises the steps of: (a) coating colloidal silica with a polymerizable monomer by mixing said silica with an organic solvent solution of said monomer and an effective amount of a polymerization catalyst, and then evaporating said solvent; (b) individualizing the coated silica by screening to product particles having a maximum size of about 90 microns; (c) polymerizing said monomer; and (d) individualizing the coated silica particles comprising the product of step (c) by screening.
Claim 2
Dependent Claim
92 words
A process for the production of a filler for use in a microfilled dental composite formulation, which process comprises the steps of: (a) coating colloidal silica with a polymerizable monomer by mixing said silica with an organic solvent solution of said monomer and an effective amount of a polymerization catalyst, and then evaporating said solvent; (b) individualizing the coated silica by screening to product particles having a maximum size of about 90 microns; (c) polymerizing said monomer; and (d) individualizing the coated silica particles comprising the product of step (c) by screening.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein the monomer is an acrylic monomer.
Claim 4
Dependent Claim
37 words
The process of claim 2 wherein the acrylic monomer contains a peroxide catalyst, and wherein step (c) is carried out by heating the product of step (b) to a temperature above the activation temperature of said catalyst.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-01 | 1992-05-02 | 1992-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-01 | 1996-05-02 | 1996-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-01 | 2000-05-02 | 2000-11-01 | $7700.00 | Window Closed / Lapsed |