US4464484A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing prefoamed polymer particles
Assignee: JAPAN STYRENE PAPER Corp A CORP OF JAPAN
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Filing: 1983-12-13
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Granted: 1984-08-07
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Expires: 2003-12-13
Abstract
Abstract Prefoamed polymer particles having excellent moldability are produced by a process comprising a step (impregnating step) of impregnating carbon dioxide or carbon dioxide and a volatile blowing agent in polymer particles, a step (dispersing step) of dispersing the polymer particles into a dispersion medium in a sealed vessel, a step (heating step) of heating the polymer particles to a temperature higher than the softening point of said polymer particles, and a step (releasing step) of opening one end of said vessel and simultaneously releasing the polymer particles and dispersion medium from inside the vessel to an atmosphere held at a pressure lower than that of the vessel. In this process, the impregnating step, dispersing step and heating step need not be altogether effected separately. These steps can be performed simultaneously in one and the same vessel.
Inventors
- 👤 Shohei Yoshimura
- 👤 Hideki Kuwabara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:43
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/22; C08J9/228; B; B29; B29C; B29C44/00; B29C44/34; B29C44/3461; C08J9/04; C08J9/12; C08J9/122; C08J9/16; C08J9/18; Y; Y10; Y10S; Y10S264/00; Y10S264/09; Y10S264/15
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
88 words
A process for producing prefoamed polymer particles, which comprises a step of impregnating carbon dioxide in polymer particles, a step of dispersing the polymer particles into a dispersion medium in a sealed vessel, a step of heating the polymer particles to a temperature higher than the softening point of said polymer particles, and a step of opening one end of said vessel and simultaneously releasing the polymer particles and dispersion medium from inside the vessel to an atmosphere held at a pressure lower than that of the vessel.
Claim 2
Dependent Claim
88 words
A process for producing prefoamed polymer particles, which comprises a step of impregnating carbon dioxide in polymer particles, a step of dispersing the polymer particles into a dispersion medium in a sealed vessel, a step of heating the polymer particles to a temperature higher than the softening point of said polymer particles, and a step of opening one end of said vessel and simultaneously releasing the polymer particles and dispersion medium from inside the vessel to an atmosphere held at a pressure lower than that of the vessel.
Claim 3
Dependent Claim
30 words
The process of claim 1 wherein 5 to 50 parts by weight of carbon dioxide per 100 parts by weight of the polymer particles is impregnated in the polymer particles.
Claim 4
Dependent Claim
93 words
A process for producing prefoamed polymer particles, which comprises a step of impregnating carbon dioxide and a volatile blowing agent in polymer particles, a step of dispersing the polymer particles into a dispersion medium in a sealed vessel, a step of heating the polymer particles to a temperature higher than the softening point of said polymer particles, and a step of opening one end of said vessel and simultaneously releasing the polymer particles and dispersion medium from inside the vessel to an atmosphere held at a pressure lower than that of the vessel.
Claim 5
Dependent Claim
93 words
A process for producing prefoamed polymer particles, which comprises a step of impregnating carbon dioxide and a volatile blowing agent in polymer particles, a step of dispersing the polymer particles into a dispersion medium in a sealed vessel, a step of heating the polymer particles to a temperature higher than the softening point of said polymer particles, and a step of opening one end of said vessel and simultaneously releasing the polymer particles and dispersion medium from inside the vessel to an atmosphere held at a pressure lower than that of the vessel.
Claim 6
Dependent Claim
39 words
The process of claim 3 wherein carbon dioxide and the volatile blowing agent in the total amount of 5 to 30 parts by weight per 100 parts by weight of the polymer particles are impregnated in the polymer particles.
Claim 7
Dependent Claim
30 words
The process of claim 3 wherein the volatile blowing agent is used in an amount of 20 to 800 parts by weight per 100 parts by weight of carbon dioxide.
Claim 8
Dependent Claim
17 words
The process of claim 1 or 3 wherein polymer particles made of a polyolefin resin are used.
Claim 9
Dependent Claim
51 words
The process of claim 1 or 3 wherein crystalline polymer particles are used and said particles are heated to a temperature in the range of from a temperature 10° C. lower than the melting point of said polymer to a temperature 50° C. higher than the melting point of said polymer.
Claim 10
Dependent Claim
51 words
The process of claim 1 or 3 wherein amorphous polymer particles are used and said particles are heated to a temperature in the range of from a temperature 10° C. higher than the softening point of said polymer to a temperature 70° C. higher than the softening point of said polymer.
Claim 11
Dependent Claim
21 words
The process of claim 1 or 3 wherein water, ethylene, glycol, glycerol, methanol or ethanol is used as the dispersion medium.
Claim 12
Dependent Claim
34 words
The process of claim 1 or 3 wherein the polymer particles and dispersion medium are released from inside a vessel held at 20 to 100 kg/cm 2 to an atmosphere held at atmospheric pressure.
References Cited (Backward Citations)
US2864778A
Cited
US3725320A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-07 | 1988-02-06 | 1988-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-07 | 1992-02-06 | 1992-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-07 | 1996-02-06 | 1996-08-07 | $7700.00 | Window Closed / Lapsed |