US3900434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wallboard tape joint composition and adhesive therefor containing water soluble polyacrylamide, limestone, asbestos, mica and cellulose ether
Assignee: Dow Chemical Co
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Filing: 1973-09-04
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Granted: 1975-08-19
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Expires: 1993-09-04
Abstract
Abstract Improved wallboard tape joint compositions comprising finely divided minerals, such as calcium carbonate, mica and asbestos and a conditioner, such as a watersoluble cellulose ether, are provided by employing as a binder a polyacrylamide having a low degree of hydrolysis and a particularly defined range of molecular weight whereby aqueous solutions of the polymer have a viscosity of at least 2.4 centipoises for a 0.5% solution but not more than 700 centipoises for a 5.1% solution.
Inventors
- 👤 Fabio B Bruschtein
- 👤 Dennis L Lyftgot
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:40
CPC Classifications
C; C04; C04B; C04B26/00; C04B26/02; C04B26/04; C04B26/06; C08; C08K; C08K3/00; C08K3/18; C08K3/24; C08K3/26; C08K3/34; C08L; C08L1/00; C08L1/08; C08L1/26; C08L33/00; C08L33/24; C08L33/26; C09; C09J; C09J133/00; C09J133/24; C09J133/26; C08L2666/00; C08L2666/02; C08L2666/54
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
188 words
IN A DRY POWDER COMPOSITION SUITABLE ON ADMIXTURE WITH WATER FOR ADHERING AND COVERING WALLBOARD JOINT TAPES WHICH COMPRISES A MAJOR PROPORTION OF UP TO ABOUT 88 PERCENT BY WEIGHT OF MINUS 100 MESH GROUND LIMESTONE, FROM ABOUT 2 TO ABOUT 20 PERCENT BY WEIGHT OF ASBESTOS, FROM ABOUT 5 TO ABOUT 20 PERCENT BY WEIGHT OF MINUS 100 MESH MICA, FROM ABOUT 0.25 TO ABOUT 1 PERCENT BY WEIGHT OF WATER-SOLUBLE CELLULOSE ETHER AND FROM ABOUT 1.5 TO ABOUT 5 PERCENT BY WEIGHT OF A WATER-SOLUBLE POLYACRYLAMIDE, SAID POLYACRYLAMIDE HAVING A LOW DEGREE OF HYDROLYSIS OF FROM 0 TO ABOUT 5 PERCENT, THE IMPROVEMENT WHICH CONSISTS IN EMPLOYING A POLYACRYLAMIDE CHRACTERIZED BY (1) AN OSTWALD VISCOSITY OF AT LEAST 2.4 CENTIPOISES FOR A 0.5 PERCENT BY WEIGHT SOLUTION THEREOF IN DISTILLED WATER AND (2) A BROOKFIELD VISCOSITY OF NO GREATER THAN 700 CENTIPOISES FOR A 5.1 PERCENT BY WEIGHT SOLUTION THEREOF IN AQUEOUS 1 PERCENT BORAX SOLUTION, SAID POLYACRYLAMIDE BEING IN THE FORM OF FINELY DIVIDED SOLIDS HAVING A PARTICLE SIZE SUCH THAT SUBSTANTIALLY 100 PERCENT THEREOF PASSES THROUGH A SCREEN HAVING 35 MESHES TO THE INCH.
Claim 2
Dependent Claim
188 words
IN A DRY POWDER COMPOSITION SUITABLE ON ADMIXTURE WITH WATER FOR ADHERING AND COVERING WALLBOARD JOINT TAPES WHICH COMPRISES A MAJOR PROPORTION OF UP TO ABOUT 88 PERCENT BY WEIGHT OF MINUS 100 MESH GROUND LIMESTONE, FROM ABOUT 2 TO ABOUT 20 PERCENT BY WEIGHT OF ASBESTOS, FROM ABOUT 5 TO ABOUT 20 PERCENT BY WEIGHT OF MINUS 100 MESH MICA, FROM ABOUT 0.25 TO ABOUT 1 PERCENT BY WEIGHT OF WATER-SOLUBLE CELLULOSE ETHER AND FROM ABOUT 1.5 TO ABOUT 5 PERCENT BY WEIGHT OF A WATER-SOLUBLE POLYACRYLAMIDE, SAID POLYACRYLAMIDE HAVING A LOW DEGREE OF HYDROLYSIS OF FROM 0 TO ABOUT 5 PERCENT, THE IMPROVEMENT WHICH CONSISTS IN EMPLOYING A POLYACRYLAMIDE CHRACTERIZED BY (1) AN OSTWALD VISCOSITY OF AT LEAST 2.4 CENTIPOISES FOR A 0.5 PERCENT BY WEIGHT SOLUTION THEREOF IN DISTILLED WATER AND (2) A BROOKFIELD VISCOSITY OF NO GREATER THAN 700 CENTIPOISES FOR A 5.1 PERCENT BY WEIGHT SOLUTION THEREOF IN AQUEOUS 1 PERCENT BORAX SOLUTION, SAID POLYACRYLAMIDE BEING IN THE FORM OF FINELY DIVIDED SOLIDS HAVING A PARTICLE SIZE SUCH THAT SUBSTANTIALLY 100 PERCENT THEREOF PASSES THROUGH A SCREEN HAVING 35 MESHES TO THE INCH.
Claim 3
Dependent Claim
30 words
A composition according to claim 1 wherein the polyacrylamide is characterized by a viscosity of 2.45 to 2.7 centipoises for a 0.5 percent by weight solution under the test conditions.
Claim 4
Dependent Claim
20 words
A composition according to claim 2 wherein the polyacrylamide is hydrolyzed to the extent of 0 to about 1 percent.
Claim 5
Dependent Claim
36 words
A composition according to claim 1 wherein the mineral filler consists essentially of about 75 to 88 percent of ground limestone, about 3 to 10 percent of asbestos and about 5 to 20 percent of mica.
Claim 6
Dependent Claim
184 words
A dry powder composition suitable on admixture with water for adhering and covering wallboard joint tapes which comprises in finely ground form from about 55 to 88 percent of limestone, from about 2 to 20 percent of asbestos, from about 5 to 20 percent of mica, from 0.25 to 1 percent of a water-soluble cellulose ether and from about 1.5 to about 5 percent by weight of a polyacrylamide, having a low degree of hydrolysis in the range of 0 to 5 percent and characterized by (1) an Ostwald viscosity of at least 2.4 centipoises for a 0.5 percent by weight solution thereof in distilled water adjusted to a pH of 3 and at a temperature of 25*C. and (2) a Brookfield viscosity of not more than 700 centipoises for an aqueous 5.1 percent by weight solution thereof in 1 percent borax solution at a pH of 9.2 and at a temperature of 25*C. said polyacrylamide being in the form of finely divided solids having a particle size such that substantially 100 percent thereof passes through a screen having 35 meshes to the inch.
Claim 7
Dependent Claim
184 words
A dry powder composition suitable on admixture with water for adhering and covering wallboard joint tapes which comprises in finely ground form from about 55 to 88 percent of limestone, from about 2 to 20 percent of asbestos, from about 5 to 20 percent of mica, from 0.25 to 1 percent of a water-soluble cellulose ether and from about 1.5 to about 5 percent by weight of a polyacrylamide, having a low degree of hydrolysis in the range of 0 to 5 percent and characterized by (1) an Ostwald viscosity of at least 2.4 centipoises for a 0.5 percent by weight solution thereof in distilled water adjusted to a pH of 3 and at a temperature of 25*C. and (2) a Brookfield viscosity of not more than 700 centipoises for an aqueous 5.1 percent by weight solution thereof in 1 percent borax solution at a pH of 9.2 and at a temperature of 25*C. said polyacrylamide being in the form of finely divided solids having a particle size such that substantially 100 percent thereof passes through a screen having 35 meshes to the inch.
Claim 8
Dependent Claim
19 words
A composition according to claim 5 wherein the Brookfield viscosity of the polyacrylamide is no greater than 600 centipoises.
Claim 9
Dependent Claim
22 words
A composition according to claim 6 wherein the polyacrylamide is employed in the amount of from 2 to 3 percent by weight.
References Cited (Backward Citations)
US3793269A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |