US5133913A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing a foamed resin using a blowing and extracting agent
Assignee: Toyo Engineering Corp
•
Filing: 1989-12-13
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Granted: 1992-07-28
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Expires: 2009-12-13
Abstract
Abstract There is disclosed a method for producing a foamed resin which incolves the steps of removing volatile substances from a polymer by contacting the polymer with an extractant and foaming the purified polymer by using the same extractant dissolved in the polymer as a foaming agent. According to the disclosure the purification and blowing of a polymer can be carried out efficiently and economically with a purification sufficient to meet market demand and with a desired blowing expansion rate.
Inventors
- 👤 Hisashi Miyakawa
- 👤 Takanobu Shinohara
- 👤 Tetsuo Maeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:16
CPC Classifications
B; B01; B01D; B01D11/00; B01D11/02; B01D11/0203; C; C08; C08G; C08G85/00; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/122; C08J9/14
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
82 words
In a method for producing a foamed polymer, the improvement comprising contacting a molten ppolymer containing volatile components with a flowing extractant for said volatile components in an extractor at a pressure and temperature sufficient to remove said volatile components from said molten polymer and dissolve said extractant therein and conducting foam molding with said polymer having said extractant dissolved therein under conditions such that said dissolved extractant serves as a blowing agent for said polymer and causes said polymer to foam.
Claim 2
Dependent Claim
82 words
In a method for producing a foamed polymer, the improvement comprising contacting a molten ppolymer containing volatile components with a flowing extractant for said volatile components in an extractor at a pressure and temperature sufficient to remove said volatile components from said molten polymer and dissolve said extractant therein and conducting foam molding with said polymer having said extractant dissolved therein under conditions such that said dissolved extractant serves as a blowing agent for said polymer and causes said polymer to foam.
Claim 3
Dependent Claim
15 words
The method as claimed in claim 1, wherein the extractant is in a supercritical state.
Claim 4
Dependent Claim
20 words
The method as claimed in claim 1, wherein the extractant in the extraction operation is used in the sub-critical state.
Claim 5
Dependent Claim
62 words
The method as claimed in claim 1, wherein the polymer is a thermoplastic polymer selected from the group consisting of polyethylene, polypropylene, polystyrene, acrylonitrile/styrene copolymer, acrylonitrile/butadiene/styrene terpolymer, polyvinyl acetate, polyacrylate, polymethacrylate, polyvinyl chloride, polyvinylidene chloride, fluorocarbon polymers, polyacrylonitrile, polyvinyl ether, polyvinyl ketone, polyethers, thermoplastic polyesters, polyamides, styrene/butadiene polymers, diene polymers, polyurethane polymers, urea polymers, phenol polymers, polyxylylene, polycarbonate, polyphenylene oxide, and polysulfone.
Claim 6
Dependent Claim
15 words
The method as claimed in claim 1, wherein the molten polymer comprises a polystyrene polymer.
Claim 7
Dependent Claim
35 words
The method as claimed in claim 1, wherein the extractant is selected from the group consisting of carbon dioxide, dinitrogen oxide, carbon disulfide, an aliphatic hydrocarbon, a halogenated hydrocarbon, an aromatic hydrocarbon, and mixtures thereof.
Claim 8
Dependent Claim
21 words
The method as claimed in claim 1, wherein said pressure is in a range of 20 to 500 kg/cm 2 G.
Claim 9
Dependent Claim
22 words
The method as claimed in claim 1, wherein said temperature is at least as high as the melting point of the polymer.
Claim 10
Dependent Claim
31 words
The method as claimed in claim 1, wherein the volatile components to be removed is an impurity selected from the group consisting of an unreacted monomer, a solvent and an oligomer.
Claim 11
Dependent Claim
14 words
The method as claimed in claim 1, wherein the extractor is a tank-type extractor.
Claim 12
Dependent Claim
22 words
The method as claimed in claim 1, wherein the extractor is a packed tower-type, a tray tower-type or a spray tower-type extractor.
Claim 13
Dependent Claim
24 words
The method as claimed in claim 1, wherein said contacting of said molten polymer with said extractant occurs in plural extractors arranged in parallel.
Claim 14
Dependent Claim
24 words
The method as claimed in claim 1, wherein said contacting of said molten polymer with said extractant occurs in plural extractors arranged in series.
Claim 15
Dependent Claim
17 words
The method as claimed in claim 1, wherein said foam molding is carried out in the extractor.
Claim 16
Dependent Claim
27 words
The method as claimed in claim 1, wherein a mold for foaming is previously placed in the extractor before said molten polymer is contacted with said extractant.
Claim 17
Dependent Claim
30 words
The method as claimed in claim 1, wherein said foam molding is carried out in a storage tank in which the polymer containing the extractant is supplied from the extractor.
Claim 18
Dependent Claim
30 words
The method as claimed in claim 16, wherein the polymer in a melted state is spouted out of a blow nozzle provided on said storage tank during said foam molding.
Claim 19
Independent Claim
104 words
A method for producing a foamed polymer from a molten polymer having a volatile impurity level of at least 400 ppm, said method comprising the steps of contacting said molten polymer with a flowing extractant for said volatile impurity in an extractor at a temperature and pressure sufficient to lower said volatile impurity level in said polymer to no higher than 100 ppm and dissolve said extractant therein; stopping the contact of said polymer with said flowing extractant; and reducing said pressure on said polymer such that said dissolved extractant serves as a blowing agent for said polymer and causes said polymer to foam.
Claim 20
Independent Claim
104 words
A method for producing a foamed polymer from a molten polymer having a volatile impurity level of at least 400 ppm, said method comprising the steps of contacting said molten polymer with a flowing extractant for said volatile impurity in an extractor at a temperature and pressure sufficient to lower said volatile impurity level in said polymer to no higher than 100 ppm and dissolve said extractant therein; stopping the contact of said polymer with said flowing extractant; and reducing said pressure on said polymer such that said dissolved extractant serves as a blowing agent for said polymer and causes said polymer to foam.
Claim 21
Dependent Claim
15 words
The method as claimed in claim 18, wherein said extractant is in a supercritical state.
Claim 22
Dependent Claim
12 words
The method as claimed in claim 18, wherein said polymer is polystyrene.
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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) | 1995-07-28 | 1996-01-27 | 1996-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-28 | 2000-01-27 | 2000-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-28 | 2004-01-27 | 2004-07-28 | $7700.00 | Window Closed / Lapsed |