US4443393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of pressurizing treatment of pre-foamed particles of polyolefin resin
Assignee: JSP Corp
•
Filing: 1982-12-07
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Granted: 1984-04-17
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Expires: 2002-12-07
Abstract
Abstract A method for pressurizing pre-foamed particles of a polyolefin resin by maintaining the pre-foamed particles in an atmosphere of a pressurized gas to impart a predetermined internal pressure thereto, which comprises first maintaining the particles under a pressure which does not cause shrinkage to the particles, and then increasing the applied pressure gradually under conditions which do not cause shrinkage to the particles.
Inventors
- 👤 Hiroyuki Akiyama
- 👤 Hideki Kuwabara
- 👤 Toru Yamaguchi
- 👤 Masahiko Kishida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:56
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/22; C08J9/228; B; B29; B29C; B29C44/00; B29C44/34; B29C44/3461; C08J2323/00; C08J2323/02; Y; Y10; Y10S; Y10S264/00; Y10S264/09; Y10S264/15
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
135 words
A method for pressurizing pre-foamed particles of a polyolefin resin by maintaining the pre-foamed particles in an atmosphere of a pressurized gas to impart thereto an internal pressure of from 0.2 to 2.5 kg/cm 2 (G), which comprises subjecting the particles while at room temperature or elevated temperature to an initial pressure of not more than 0.5 kg/cm 2 (G) by feeding an inorganic gas or a mixture of an inorganic gas and a blowing agent into a vessel, and said initial pressure not causing shrinkage to the particles, and thereafter gradually increasing the applied pressure stepwise or continuously at a rate of not more than 0.2 kg/cm 2 (g) per hour until the pressure reach 0.7 to 3 kg/cm 2 (G), said step of increasing the applied pressure not causing shrinkage to the particles.
Claim 2
Independent Claim
135 words
A method for pressurizing pre-foamed particles of a polyolefin resin by maintaining the pre-foamed particles in an atmosphere of a pressurized gas to impart thereto an internal pressure of from 0.2 to 2.5 kg/cm 2 (G), which comprises subjecting the particles while at room temperature or elevated temperature to an initial pressure of not more than 0.5 kg/cm 2 (G) by feeding an inorganic gas or a mixture of an inorganic gas and a blowing agent into a vessel, and said initial pressure not causing shrinkage to the particles, and thereafter gradually increasing the applied pressure stepwise or continuously at a rate of not more than 0.2 kg/cm 2 (g) per hour until the pressure reach 0.7 to 3 kg/cm 2 (G), said step of increasing the applied pressure not causing shrinkage to the particles.
Claim 3
Independent Claim
135 words
A method for pressurizing pre-foamed particles of a polyolefin resin by maintaining the pre-foamed particles in an atmosphere of a pressurized gas to impart thereto an internal pressure of from 0.5 to 0.9 kg/cm 2 (G), which comprises subjecting the particles while at room temperature or elevated temperature to an initial pressure of not more than 0.4 kg/cm 2 (G) by feeding an inorganic gas or a mixture of an inorganic gas and a blowing agent into a vessel, and said initial pressure not causing shrinkage to the particles, and thereafter gradually increasing the applied pressure stepwise or continuously at a rate of from 0.03 to 0.2 kg/cm 2 (G) per hour, until the pressure reaches 0.9 to 2 kg/cm 2 (G), said step of increasing the applied pressure not causing shrinkage to the particles.
Claim 4
Independent Claim
135 words
A method for pressurizing pre-foamed particles of a polyolefin resin by maintaining the pre-foamed particles in an atmosphere of a pressurized gas to impart thereto an internal pressure of from 0.5 to 0.9 kg/cm 2 (G), which comprises subjecting the particles while at room temperature or elevated temperature to an initial pressure of not more than 0.4 kg/cm 2 (G) by feeding an inorganic gas or a mixture of an inorganic gas and a blowing agent into a vessel, and said initial pressure not causing shrinkage to the particles, and thereafter gradually increasing the applied pressure stepwise or continuously at a rate of from 0.03 to 0.2 kg/cm 2 (G) per hour, until the pressure reaches 0.9 to 2 kg/cm 2 (G), said step of increasing the applied pressure not causing shrinkage to the particles.
References Cited (Backward Citations)
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US3126432A
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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) | 1987-04-17 | 1987-10-17 | 1988-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-17 | 1991-10-17 | 1992-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-17 | 1995-10-17 | 1996-04-17 | $7700.00 | Window Closed / Lapsed |