Patent US5519971A successfully refreshed from Google Patents.
Patent US5079277A successfully refreshed from Google Patents.
US5079277A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Poly-vinylphosphonic acid and metal oxide or cermet or glass ionomer cement
Assignee: BTG International Ltd
•
Filing: 1989-04-27
•
Granted: 1992-01-07
•
Expires: 2009-04-27
Abstract
Abstract A glass ionomer cement composition comprises poly(vinyl phosphonic acid) dissolved in its own mass of water; and (in treble the total mass of the solution) a powder, being glass or MgO or a cermet. The powder has to be deactivated so that the setting reaction with the acid is not too fast, and this is achieved either by a raised Si:Al ratio or by heat-treating.
Inventors
- 👤 Alan D. Wilson
- 👤 John Ellis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:51
CPC Classifications
C; C04; C04B; C04B28/00; C04B28/28; A; A61; A61K; A61K6/00; A61K6/80; A61K6/829; A61K6/849; A61K6/876; A61K6/884; A61K6/887; A61K6/889; C04B14/00; C04B14/02; C04B14/04; C04B14/22; C04B40/00; C04B40/0028; C04B40/0039; C04B2111/00; C04B2111/00474; C04B2111/00836
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
68 words
A cement composition, comprising an intimately blended mixture of a water-containing liquid, a cation-crosslinkable polymeric acid containing on average one phosphonic acid group per one to three backbone carbon atoms, and a cation-leachable surgically acceptable glass powder containing Si and Al in the mole proportions 0.6-0.2:1 if previously heat-treated, otherwise exceeding 1.6:1, in the mass proportions (1-x) polymeric acid: (1-5) glass: x liquid, where x is from 0.3-0.7.
Claim 2
Dependent Claim
68 words
A cement composition, comprising an intimately blended mixture of a water-containing liquid, a cation-crosslinkable polymeric acid containing on average one phosphonic acid group per one to three backbone carbon atoms, and a cation-leachable surgically acceptable glass powder containing Si and Al in the mole proportions 0.6-0.2:1 if previously heat-treated, otherwise exceeding 1.6:1, in the mass proportions (1-x) polymeric acid: (1-5) glass: x liquid, where x is from 0.3-0.7.
Claim 3
Dependent Claim
17 words
A cement composition according to claim 1, wherein the glass has been metallised to form a cement.
Claim 4
Dependent Claim
17 words
A cement composition according to claim 1, wherein the glass has been washed in a dilute acid.
Claim 5
Dependent Claim
29 words
A cement composition according to claim 3, wherein the dilute acid is acetic acid in a concentration of y% and the washing has been for z hours where yz<4.
Claim 6
Dependent Claim
22 words
A cement composition according to claim 1 wherein the glass powder consists of particles all of which are smaller than 100 microns.
Claim 7
Dependent Claim
23 words
A cement composition according to claim 1, wherein the glass powder has been heat-treated at least 400° C. for at least 40 minutes.
Claim 8
Dependent Claim
51 words
A cement composition, comprising an intimately blended mixture of a water-containing liquid, a cation-crosslinkable polymeric acid containing on average one phosphonic acid group per one to three backbone carbon atoms, and a metal oxide powder, in the mass proportions (1-x) polymeric acid: (1-5) oxide: x liquid, where x is from 0.3-0.7.
Claim 9
Dependent Claim
51 words
A cement composition, comprising an intimately blended mixture of a water-containing liquid, a cation-crosslinkable polymeric acid containing on average one phosphonic acid group per one to three backbone carbon atoms, and a metal oxide powder, in the mass proportions (1-x) polymeric acid: (1-5) oxide: x liquid, where x is from 0.3-0.7.
Claim 10
Dependent Claim
16 words
A cement composition according to claim 7, wherein the metal oxide is CaO, ZnO or MgO.
Claim 11
Dependent Claim
21 words
A cement composition according to claim 8, wherein the metal oxide is MgO which has been heat-treated at least 900° C.
Claim 12
Dependent Claim
16 words
A composition according to claim 1, wherein the polymeric acid is or comprises poly(vinyl phosphonic acid).
Claim 13
Dependent Claim
14 words
A composition according to claim 10, wherein the polymer acid further comprises poly(acrylic acid).
Claim 14
Dependent Claim
11 words
A composition according to claim 1, wherein the liquid is water.
Claim 15
Dependent Claim
16 words
A pack comprising two pastes which when mixed form a cement composition according to claim 1.
Claim 16
Dependent Claim
26 words
A pack according to claim 13, wherein the first paste contains the acid(s) plus water and the second contains the powder suspended in aqueous thickening agent.
Claim 17
Dependent Claim
25 words
A pack comprising the acid(s) in dry form and the powder in the proportions and the compositions of a cement composition according to claim 1.
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) | 1995-01-06 | 1995-07-08 | 1996-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-06 | 1999-07-08 | 2000-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-06 | 2003-07-08 | 2004-01-07 | $7700.00 | Window Closed / Lapsed |