US4140536A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gypsum products
Assignee: Gypsum Industries Ltd
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Filing: 1978-03-01
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Granted: 1979-02-20
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Expires: 1998-03-01
Abstract
Abstract This invention relates to a method of making a gypsum product wherein a hot homogeneous mixture of pitch and a suitable organic material are mixed with gypsum and water to form a slurry. This slurry is then formed, allowed to set and then heated to a temperature above the melting points of both constituents of the mixture but below the temperature at which there is any significant deterioration of the product.
Inventors
- 👤 Simbert W. Maier
- 👤 Adriaan J. H. Lamprecht
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:16
CPC Classifications
C; C04; C04B; C04B28/00; C04B28/14; C04B2111/00; C04B2111/00474; C04B2111/00612; C04B2111/0062; C04B2111/20; C04B2111/27
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
143 words
A method of making gypsum products comprising the steps of: A. making at elevated temperatures a homogeneous liquid mixture of pitch and non-wettable organic material which material, at ambient temperatures, is substantially immiscible with pitch and is a solid, the pitch to organic material ratio being between 25:1 and 7:1; B. mixing the liquid mixture formed in Step A with gypsum and water to form a slurry having the correct water demand, the weight of liquid mixture being equal to from ten to twenty percent of the weight of hemi-hydrate gypsum on a dry weight basis; C. forming the resultant slurry into a predetermined shape; D. allowing the formed slurry to set; and E. heating the thus set slurry to a temperature high enough to melt both the pitch and the organic material but low enough to prevent deterioration of the set slurry.
Claim 2
Independent Claim
143 words
A method of making gypsum products comprising the steps of: A. making at elevated temperatures a homogeneous liquid mixture of pitch and non-wettable organic material which material, at ambient temperatures, is substantially immiscible with pitch and is a solid, the pitch to organic material ratio being between 25:1 and 7:1; B. mixing the liquid mixture formed in Step A with gypsum and water to form a slurry having the correct water demand, the weight of liquid mixture being equal to from ten to twenty percent of the weight of hemi-hydrate gypsum on a dry weight basis; C. forming the resultant slurry into a predetermined shape; D. allowing the formed slurry to set; and E. heating the thus set slurry to a temperature high enough to melt both the pitch and the organic material but low enough to prevent deterioration of the set slurry.
Claim 3
Dependent Claim
26 words
A method as claimed in claim 1 in which the pitch to organic material ratio is in a range defined by the ratios 16:1 and 10:1.
Claim 4
Dependent Claim
18 words
A method as claimed in claim 1 in which the pitch to organic material ratio is about 15:1.
Claim 5
Dependent Claim
29 words
A method as claimed in claim 1 in which the weight of liquid mixture is about fifteen percent of the weight of hemi-hydrate gypsum on a dry weight basis.
Claim 6
Dependent Claim
24 words
A method as claimed in claim 1 in which the temperature of the liquid mixture is at least 120° C. on forming the slurry.
Claim 7
Dependent Claim
19 words
A method as claimed in claim 1 in which the pitch is a pitch and heavy residue oil compound.
Claim 8
Dependent Claim
15 words
A method as claimed in claim 1 in which the organic material is a wax.
Claim 9
Dependent Claim
42 words
A method as claimed in claim 7 in which the wax is a paraffin wax having a latent heat of fusion of 1.84 joules per gram, a viscosity at 100° C. of 3.5 centipoise and an average molecular mass of about 400.
Claim 10
Dependent Claim
40 words
A method as claimed in claim 7 in which the wax is a microwax having a melting point of about 77.2° C., an oil content of about 1.5 weight percent and a viscosity at 98.8° C. of about 8.2 centipoise.
Claim 11
Dependent Claim
26 words
A method as claimed in claim 1 in which the slurry is formed in a paper lining waterproofed by saturation with a highly penetrating bituminous compound.
Claim 12
Dependent Claim
16 words
A method as claimed in claim 10 in which the compound is a cut-back bituminous compound.
Claim 13
Dependent Claim
12 words
A product made in accordance with the method claimed in claim 1.
Claim 14
Independent Claim
188 words
A method of manufacturing a substantially waterproof shaped gypsum product, said method including the successive steps of: (1) mixing together at an elevated temperature pitch and a non-wettable organic material selected from the group consisting of micro wax, paraffin wax, fatty acids and mixtures thereof, the organic material selected being substantially unmiscible with pitch and solid at ambient temperatures, the pitch to organic material ratio being between 25:1 and 7:1, to form a homogeneous liquid mixture; (2) mixing the heated liquid mixture formed in step (1) with gypsum and water thereby forming a slurry having a predetermined water demand, the weight of liquid mixture from step (1) used to form said slurry being equal to from 10 to 20 percent of the weight of hemi-hydrate gypsum on a dry weight basis; (3) forming the slurry of step (2) into a predetermined shape; (4) allowing the thus formed slurry to set; and (5) heating the set slurry from step (4) to a temperature sufficient to melt both the pitch and the organic material without deterioration of the set slurry; thereby forming a shaped gypsum product which is substantially waterproof.
Claim 15
Independent Claim
188 words
A method of manufacturing a substantially waterproof shaped gypsum product, said method including the successive steps of: (1) mixing together at an elevated temperature pitch and a non-wettable organic material selected from the group consisting of micro wax, paraffin wax, fatty acids and mixtures thereof, the organic material selected being substantially unmiscible with pitch and solid at ambient temperatures, the pitch to organic material ratio being between 25:1 and 7:1, to form a homogeneous liquid mixture; (2) mixing the heated liquid mixture formed in step (1) with gypsum and water thereby forming a slurry having a predetermined water demand, the weight of liquid mixture from step (1) used to form said slurry being equal to from 10 to 20 percent of the weight of hemi-hydrate gypsum on a dry weight basis; (3) forming the slurry of step (2) into a predetermined shape; (4) allowing the thus formed slurry to set; and (5) heating the set slurry from step (4) to a temperature sufficient to melt both the pitch and the organic material without deterioration of the set slurry; thereby forming a shaped gypsum product which is substantially waterproof.
Claim 16
Dependent Claim
47 words
A method as claimed in claim 13 wherein the ratio of pitch to organic material is about 15:1, the weight of liquid mixture from step (1) used in step (2) is about 15 percent and the liquid mixture is added at a temperature of about 120° C.
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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) | 1982-02-19 | 1982-08-21 | 1983-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-19 | 1986-08-21 | 1987-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-19 | 1990-08-21 | 1991-02-20 | $7700.00 | Window Closed / Lapsed |