Patent US3856539A successfully refreshed from Google Patents.
US3856539A
Expired / Lapsed
US
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Solidified silica foam product and process
Assignee: Southwest Research Institute
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Filing: 1971-11-12
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Granted: 1974-12-24
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Expires: 1991-11-12
Abstract
Abstract An inorganic solidified insulating foam material having a rigid structure comprising silicic acid is made by frothing a mixture of aqueous solution of one or both of two certain alkali metal silicates, a surface tension depressant and a silicon dioxide polymer forming agent with or without the inclusion of an alkali metal silicate gelling agent. The foamed material is permitted to harden free of damaging contraction or expansion under conditions of high humidity, approaching 100% relative humidity.
Inventors
- 👤 W Mallow
- 👤 R Owen
- 👤 E Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:30
CPC Classifications
C; C04; C04B; C04B28/00; C04B28/006; C04B28/008; Y; Y02; Y02P; Y02P40/00; Y02P40/10; Y10; Y10S; Y10S65/00; Y10S65/901
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
112 words
IN A METHOD FOR MAKING A FOAMED ALKALI METAL SILICATE PRODUCT INCLUDING THE STEP OF FROTHING INTO A FOAM BY GAS ENTRAINMENT A COMPOSITION COMPRISING AN AQUEOUS SOLUTION OF ALKALI METAL SILICATE SELECTED FROM THE GROUP CONSISTING OF SODIUM SILICATE, AND POTASSIUM SILICATE, TOGETHER WITH A SURFACE TENSION DEPRESSANT, A SILICON DIOXIDE POLYMER FORMING AGENT BEING INTRODUCED INTO THE COMPOSITION IN AN AMOUNT SUFFICIENT TO MAKE THE FOAM RIGID AND RESITANT TO DEGRADATION BY WATER, SHAPING THE FROTHER PRODUCT, AND HARDENING THE SHAPED PRODUCT IN A POLYMERIZATION ZONE, THE IMPROVEMENT COMPRISING PERMITTING THE FROTHED PRODUCT TO HARDENED FREE OF DAMAGING CONTRACTION OR EXPANSION, UNDER CONDITIONS OF HIGH HUMIDITY, APPROACHING 100% RELATIVE HUMIDITY.
Claim 2
Dependent Claim
112 words
IN A METHOD FOR MAKING A FOAMED ALKALI METAL SILICATE PRODUCT INCLUDING THE STEP OF FROTHING INTO A FOAM BY GAS ENTRAINMENT A COMPOSITION COMPRISING AN AQUEOUS SOLUTION OF ALKALI METAL SILICATE SELECTED FROM THE GROUP CONSISTING OF SODIUM SILICATE, AND POTASSIUM SILICATE, TOGETHER WITH A SURFACE TENSION DEPRESSANT, A SILICON DIOXIDE POLYMER FORMING AGENT BEING INTRODUCED INTO THE COMPOSITION IN AN AMOUNT SUFFICIENT TO MAKE THE FOAM RIGID AND RESITANT TO DEGRADATION BY WATER, SHAPING THE FROTHER PRODUCT, AND HARDENING THE SHAPED PRODUCT IN A POLYMERIZATION ZONE, THE IMPROVEMENT COMPRISING PERMITTING THE FROTHED PRODUCT TO HARDENED FREE OF DAMAGING CONTRACTION OR EXPANSION, UNDER CONDITIONS OF HIGH HUMIDITY, APPROACHING 100% RELATIVE HUMIDITY.
Claim 3
Dependent Claim
29 words
A method as in claim 1 wherein the frothing is effected under superatmospheric pressure and the frothed product is permitted to expand at atmospheric pressure before hardening by polymerization.
Claim 4
Dependent Claim
12 words
A method as in claim 1 wherein the entrained gas is air.
Claim 5
Dependent Claim
28 words
A method as in claim 1 wherein the hardening is effected at a temperature not appreciably different from the temperature at which the foam reaches the polymerizing zone.
Claim 6
Dependent Claim
35 words
A method as in claim 1 wherein the hardening is effected at a temperature not more than about 10*F. cooler than the temperature at which the foam reaches the polymerizing zone, to avoid damaging contraction.
Claim 7
Dependent Claim
45 words
A method as in claim 1 wherein the foam is not physically restricted during hardening and wherein the hardening is effected at a temperature not more than about 5*F. above the temperature at which the foam reaches the polymerizing zone, to avoid damaging thermal expansion.
Claim 8
Dependent Claim
65 words
A method as in claim 1, wherein the frothing is effected at a lower temperature, without excessive pre-cure in the range of about 135* to 160*F., and the hardening is effected at a higher temperature more than 5* above the temperature at which the foam reaches the hardening and polymerizing zone, said hardening being effected while the foam is physically restricted to prevent thermal expansion.
Claim 9
Dependent Claim
24 words
A method as in claim 1 wherein the polymer forming agent is added to the composition after the composition is frothed into a foam.
Claim 10
Dependent Claim
35 words
A method as in claim 1 in which the silicon dioxide polymer agent is selected from the group consisting of sodium fluorosilicate, calcium borate, zinc borate, lithium calcium borates, sodium calcium borates and mixtures thereof.
Claim 11
Dependent Claim
25 words
A method as in claim 1 wherein the composition contains not more than about 10% of filler and reinforcement based on the resulting dry product.
Claim 12
Dependent Claim
23 words
A method as in claim 1 wherein the temperature of the frothed product is below about 200*F. when it reaches the polymerization zone.
Claim 13
Dependent Claim
29 words
A process as in claim 11 wherein the temperature of the frothed product is in the range of about 135* to about 200*F., when it reaches the polymerization zone.
Claim 14
Dependent Claim
26 words
A method as in claim 12 wherein the polymer forming agent is added to the foamed product just prior to its arrival in the polymerization zone.
Claim 15
Dependent Claim
14 words
A method as in claim 1 wherein the alkali metal silicate is sodium silicate.
Claim 16
Dependent Claim
23 words
A method as in claim 14 wherein the sodium silicate has a ratio of sodium oxide to silicon dioxide of 1:1 to 1:5.
Claim 17
Dependent Claim
16 words
A method as in claim 14 including not more than about 10% of filler and reinforcement.
Claim 18
Dependent Claim
18 words
A method as in claim 1 wherein the silicate composition further comprises an alkali metal silicate gelling agent.
Claim 19
Dependent Claim
18 words
A method as in claim 9 wherein the silicoN dioxide polymer forming agent is an alkali metal fluorosilicate.
Claim 20
Dependent Claim
19 words
A method as in claim 1 wherein the relative humidity is maintained higher than 80% during the hardening step.
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) | 1977-12-23 | 1978-06-24 | 1978-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-23 | 1982-06-24 | 1982-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-23 | 1986-06-24 | 1986-12-24 | $7700.00 | Window Closed / Lapsed |