US3915927A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the preparation of fibrous soluble calcium sulfate anhydrite
Assignee: Johns Manville Corp
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Filing: 1974-08-05
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Granted: 1975-10-28
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Expires: 1994-08-05
Abstract
Abstract A reinforced plastic article is described, in which the plastic matrix is an organic polymeric resin and the reinforcing fiber is fibrous soluble calcium sulfate anhydrite, the fibers thereof having specified dimensions. The fibers are produced by a process in which a dilute aqueous suspension of gypsum is first formed and converted to the fibrous soluble anhydrite by reaction in the presence of saturated steam at 140*C to 200*C for 0.5 to 3.0 hours.
Inventors
- 👤 Karlis L Jaunarajs
- 👤 Julie C Yang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:23
CPC Classifications
C; C04; C04B; C04B14/00; C04B14/38; C04B11/00; C04B11/02; C08; C08K; C08K3/00; C08K3/30; C08K7/00; C08K7/02; C08K7/04; C08K7/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
146 words
A RESINFORCED COMPOSITE ARTICLE COMPRISING AN ORGANIC POLYMERIC RESIN MATRIX REINFORCED WITH FIBROUS CALCIUM SULFATE ANHYDRITE PRODUCED BY A PROCESS WITH COMPRISES: A. FORMING AN AQUEOUS SUSPENSION OF GYPSUM, SAID SUSPENSION BEING NOT GREATER THAN 0.30 MOLAR IN GYPSUM, AND SAID GYPSUM PRIOR TO DISPERSION BEING IN THE FORM OF PARTICLES AT LEAST 90% OF WHICH ARE MINUS 4 MESH IN SIZE, AND B. CONVERTING THE GYPSUM IN SAID SUSPENSION TO SAID FIBROUS SOLUBLE ANHYDRITE BY REACTION IN A PRESSURE VESSEL IN THE PRESENCE OF SATURATED STEAM AT A TEMPERATURE IN THE RANGE OF FROM 140*C TO 200*C FOR A PERIOD OF 0.5 TO 3.0 HOURS, THEREBY FORMING FIBERS OF SOLUBLE CALCIUM SULFATE ANHYDRITE HAVING AN OVERALL AVERAGE LENGTH IN THE RANGE OF FROM 25 TO 70 MICRONS, INDIVIDUAL MAXIMUM LENGTHS NOT EXCEEDING 150 MICRONS, AND ASPECT RATIOS IN THE RANGE OF FROM 10:1 TO 100:1.
Claim 2
Dependent Claim
146 words
A RESINFORCED COMPOSITE ARTICLE COMPRISING AN ORGANIC POLYMERIC RESIN MATRIX REINFORCED WITH FIBROUS CALCIUM SULFATE ANHYDRITE PRODUCED BY A PROCESS WITH COMPRISES: A. FORMING AN AQUEOUS SUSPENSION OF GYPSUM, SAID SUSPENSION BEING NOT GREATER THAN 0.30 MOLAR IN GYPSUM, AND SAID GYPSUM PRIOR TO DISPERSION BEING IN THE FORM OF PARTICLES AT LEAST 90% OF WHICH ARE MINUS 4 MESH IN SIZE, AND B. CONVERTING THE GYPSUM IN SAID SUSPENSION TO SAID FIBROUS SOLUBLE ANHYDRITE BY REACTION IN A PRESSURE VESSEL IN THE PRESENCE OF SATURATED STEAM AT A TEMPERATURE IN THE RANGE OF FROM 140*C TO 200*C FOR A PERIOD OF 0.5 TO 3.0 HOURS, THEREBY FORMING FIBERS OF SOLUBLE CALCIUM SULFATE ANHYDRITE HAVING AN OVERALL AVERAGE LENGTH IN THE RANGE OF FROM 25 TO 70 MICRONS, INDIVIDUAL MAXIMUM LENGTHS NOT EXCEEDING 150 MICRONS, AND ASPECT RATIOS IN THE RANGE OF FROM 10:1 TO 100:1.
Claim 3
Dependent Claim
28 words
The reinforced composite article of claim 1 wherein said organic polymeric resin matrix comprises a resin selected from the group consisting of polyesters, polyolefins, poly(vinyl halides) and polystyrene.
Claim 4
Dependent Claim
22 words
The reinforced composite article of claim 2 wherein said resin is a polyolefin selected from the group consisting of polyethylene and polypropylene.
Claim 5
Dependent Claim
14 words
The reinforced composite article of claim 2 wherein said poly(vinyl halide) is poly(vinyl chloride).
Claim 6
Dependent Claim
29 words
The reinforced composite article of claim 1 wherein the weight ratio of polymeric resin to fibrous soluble anhydrite is in the range of from about 2:1 to about 12:1.
Claim 7
Dependent Claim
19 words
The reinforced composite article of claim 5 wherein said weight ratio is in the range of 2:1 to 6:1.
Claim 8
Dependent Claim
22 words
The reinforced composite article of claim 1 wherein said polymeric resin is extended by addition of up to about 50% of filler.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |