Patent US4048272A successfully refreshed from Google Patents.
US4048272A
Expired / Lapsed
US
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Method for preparing improved expanded polystyrene sheet
Assignee: Lyondell Chemical Technology LP
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Filing: 1976-01-02
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Granted: 1977-09-13
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Expires: 1996-01-02
Abstract
Abstract Expanded styrene polymer sheet material is produced by extruding expandable and/or general purpose styrene polymer with a conventional blowing agent, a nucleating system and a small amount of finely divided hydrophobic silicon dioxide. The resulting product has very fine, uniformly sized pores and improved flexibility.
Inventors
- 👤 John P. Spicuzza, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:05
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/0066; B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/46; B29C44/50; B29C44/505; C08K; C08K3/00; C08K3/01; C08K3/34; C08K3/36; B29K; B29K2025/00; B29K2105/00; B29K2105/06; B29K2105/16; B29L; B29L2007/00; B29L2007/002; C08J2325/00; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/13; Y10S264/17
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
61 words
In a process for producing microcellular expanded styrene polymer sheet by extruding a mixture containing styrene polymer, a blowing agent and a nucleating system, the improvement comprising extruding with said mixture about 0.002 to 2%, based on the total weight of styrene polymer, of hydrophobic silica, said hydrophobic silica being uniformly distributed throughout said mixture whereby said sheet has improved flexability.
Claim 2
Dependent Claim
61 words
In a process for producing microcellular expanded styrene polymer sheet by extruding a mixture containing styrene polymer, a blowing agent and a nucleating system, the improvement comprising extruding with said mixture about 0.002 to 2%, based on the total weight of styrene polymer, of hydrophobic silica, said hydrophobic silica being uniformly distributed throughout said mixture whereby said sheet has improved flexability.
Claim 3
Dependent Claim
23 words
The improved process of claim 1 wherein said hydrophobic silica is blended with the styrene polymer before it is fed into the extruder.
Claim 4
Dependent Claim
22 words
The improved process of claim 1 wherein said hydrophobic silica is added to the styrene polymer in the barrel of the extruder.
Claim 5
Dependent Claim
29 words
The improved process of claim 1 wherein the amount of hydrophobic silica extruded with said mixture is about 0.01 to 0.5%, based on the total weight of styrene polymer.
Claim 6
Dependent Claim
16 words
The improved process of claim 1 wherein expandable polystyrene material is used in forming said mixture.
Claim 7
Dependent Claim
39 words
The improved process of claim 1 wherein a portion of the styrene polymer is general purpose polystyrene and a portion of the blowing agent is injected into the molten polymer while it is in the barrel of the extruder.
Claim 8
Dependent Claim
33 words
The improved process of claim 1 wherein the styrene polymer is general purpose polystyrene and the blowing agent is injected into the molten polymer while it is in the barrel of the extruder.
Claim 9
Dependent Claim
69 words
A process of extruding expanded styrene polymer sheet having a small and uniform cell size from styrene polymer feedstock comprising extruding a mixture comprised of the styrene polymer, about 3-10% blowing agent, about 0.01 to 5% nucleating system, and about 0.002 to 2% hydrophobic silica having an average particle size of about 1 to 100 millimicrons, said percentages being based on the total weight of styrene polymer being extruded.
Claim 10
Dependent Claim
69 words
A process of extruding expanded styrene polymer sheet having a small and uniform cell size from styrene polymer feedstock comprising extruding a mixture comprised of the styrene polymer, about 3-10% blowing agent, about 0.01 to 5% nucleating system, and about 0.002 to 2% hydrophobic silica having an average particle size of about 1 to 100 millimicrons, said percentages being based on the total weight of styrene polymer being extruded.
Claim 11
Dependent Claim
57 words
The process of claim 8 wherein said blowing agent, nucleating system and hydrophobic silica are present in the amounts of about 5 to 7%, about 0.05 to 3% and about 0.01 to 0.5% respectively, based on the total weight of styrene polymer and said hydrophobic silica has an average particle size of about 2 to 50 millimicrons.
Claim 12
Dependent Claim
40 words
The process of claim 9 wherein the styrene polymer is polystyrene, the blowing agent is pentane, the nucleating system is comprised of an organic acid and alkali or alkaline earth metal carbonate, and the hydrophobic silica is hydrophobic fumed silica.
Claim 13
Dependent Claim
17 words
The process of claim 10 wherein the nucleating system is comprised of citric acid and sodium bicarbonate.
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) | 1980-09-12 | 1981-03-14 | 1981-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-12 | 1985-03-14 | 1985-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-12 | 1989-03-14 | 1989-09-13 | $7700.00 | Window Closed / Lapsed |