US4778829A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing pre-expanded particles of thermoplastic resin
Assignee: Kanegafuchi Chemical Industry Co Ltd
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Filing: 1987-08-11
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Granted: 1988-10-18
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Expires: 2007-08-11
Abstract
Abstract A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing the dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40 DEG C. According to the process of the present invention, there can be obtained pre-expanded thermoplastic resin particles with a large average diameter of cells. By molding the pre-expanded particles obtained by the present invention, molded articles which are small in dimensional shrinkage and excellent in surface appearance can be obtained without imparting expandability to the particles or aging the particles under pressure prior to molding.
Inventors
- 👤 Tadayuki Ichimura
- 👤 Kenichi Senda
- 👤 Masao Ando
- 👤 Hirofumi Maeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:20
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/22; C08J9/228; C08J9/232; B; B29; B29C; B29C44/00; B29C44/34; B29C44/3461; B29C44/36; B29C44/38; B29C44/44; B29C44/445; B29C44/3415; B29C44/3426; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2995/00; B29K2995/0037; B29K2995/0063; C08J2323/00; C08J2323/02
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
64 words
A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing said dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40° C.
Claim 2
Dependent Claim
64 words
A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing said dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40° C.
Claim 3
Dependent Claim
138 words
A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing said dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40° C.; said thermoplastic resin being a member selected from the group consisting of a styrene polymer, a vinyl chloride polymer, a polyamide, a polyester resin, a polypropylene resin, a low density polyethylene, a medium density polyethylene, a high density polyethylene, a crosslinked linear low density polyethylene, a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and methyl methacrylate, an ionomer resin, poly-1-butene, polypentene, and a terpolymer of ethylene, acrylic acid and maleic anhydride.
Claim 4
Dependent Claim
138 words
A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing said dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40° C.; said thermoplastic resin being a member selected from the group consisting of a styrene polymer, a vinyl chloride polymer, a polyamide, a polyester resin, a polypropylene resin, a low density polyethylene, a medium density polyethylene, a high density polyethylene, a crosslinked linear low density polyethylene, a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and methyl methacrylate, an ionomer resin, poly-1-butene, polypentene, and a terpolymer of ethylene, acrylic acid and maleic anhydride.
Claim 5
Dependent Claim
74 words
A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing said dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40° C., said thermoplastic resin being a non-crosslinked linear low density polyethylene.
Claim 6
Dependent Claim
74 words
A process for preparing pre-expanded particles of a thermoplastic resin, which comprises heating an aqueous dispersion of thermoplastic resin particles containing a volatile blowing agent to a high temperature under pressure in a pressure vessel, and releasing said dispersion into an atmosphere maintained at a lower pressure than the pressure in the pressure vessel and at a temperature of not lower than 40° C., said thermoplastic resin being a non-crosslinked linear low density polyethylene.
Claim 7
Dependent Claim
32 words
The process of claim 1, wherein said atmosphere is an atmosphere in which hot water of 40° to 90° C. is sprayed or injected from a plurality of nozzles having small holes.
Claim 8
Dependent Claim
32 words
The process of claim 2, wherein said atmosphere is an atmosphere in which hot water of 40° to 90° C. is sprayed or injected from a plurality of nozzles having small holes.
Claim 9
Dependent Claim
32 words
The process of claim 3, wherein said atmosphere is an atmosphere in which hot water of 40° to 90° C. is sprayed or injected from a plurality of nozzles having small holes.
Claim 10
Dependent Claim
16 words
The process of claim 1, wherein said atmosphere is an atmosphere in which steam is introduced.
Claim 11
Dependent Claim
16 words
The process of claim 2, wherein said atmosphere is an atmosphere in which steam is introduced.
Claim 12
Dependent Claim
16 words
The process of claim 3, wherein said atmosphere is an atmosphere in which steam is introduced.
Claim 13
Dependent Claim
49 words
The process of claim 1, wherein said dispersion is brought into contact with an atmosphere in which steam is introduced and then brought into contact with an atmosphere in which hot water of 40° to 90° C. is sprayed or injected from a plurality of nozzles having small holes.
Claim 14
Dependent Claim
49 words
The process of claim 2, wherein said dispersion is brought into contact with an atmosphere in which steam is introduced and then brought into contact with an atmosphere in which hot water of 40° to 90° C. is sprayed or injected from a plurality of nozzles having small holes.
Claim 15
Dependent Claim
49 words
The process of claim 3, wherein said dispersion is brought into contact with an atmosphere in which steam is introduced and then brought into contact with an atmosphere in which hot water of 40° to 90° C. is sprayed or injected from a plurality of nozzles having small holes.
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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) | 1991-10-18 | 1992-04-18 | 1992-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-18 | 1996-04-18 | 1996-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-18 | 2000-04-18 | 2000-10-18 | $7700.00 | Window Closed / Lapsed |