EP0140059A1
Expired / Lapsed
EP
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Pre-expanding process and apparatus for the same
Assignee: Kanegafuchi Chemical Industry Co Ltd
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Filing: 1984-09-07
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Granted: —
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Expires: 2004-09-07
Abstract
Abstract A process for preparing pre-expanded particles of a thermoplastic resin which comprises; heating under an elevated pressure an aqueous dispersion comprising thermoplastic resin particles (2) containing a volatile foaming agent and an aqueous medium (3) in a pressure vessel (1); releasing the dispersion from the pressure vessel (1) into a space within a sealed low-pressure vessel (7) wherein the pressure is lower than that in the pressure vessel (1), whereby expanding the thermoplastic resin particles (2) to give pre-expanded particles (8); and simultaneously recovering the foaming agent volatilized from the thermoplastic resin particles by discharging the foaming agent out of the space in the low-pressure vessel (7) with controlling the pressure in the low-pressure vessel (7) to substantially a given pressure. According to the process, the release of the volatile foaming agent into the air is prevented.
Inventors
- 👤 Hirofumi Maeda
- 👤 Kyoichi Nakamura
- 👤 Hisatoshi Fukui
- 👤 Toshihiro Hatamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 16:18
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/3461; C; C08; C08J; C08J11/00; C08J11/02; C08J9/00; C08J9/22; C08J9/228
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
A process for preparing pre-expanded particles of a thermoplastic resin which comprises; heating under an elevated pressure an aqueous dispersion comprising thermoplastic resin particles containing a volatile foaming agent and an aqueous medium in a pressure vessel; releasing the dispersion from the pressure vessel into a space within a sealed low-pressure vessel wherein the pressure is lower than that in the pressure vessel, whereby expanding the thermoplastic resin particles to give pre-expanded particles; and simultaneously recovering the foaming agent volatilized from the thermoplastic resin particles by discharging the foaming agent out of the space in the low-pressure vessel with controlling the pressure in the low-pressure vessel to substantially a given pressure.
Claim 2
Dependent Claim
111 words
A process for preparing pre-expanded particles of a thermoplastic resin which comprises; heating under an elevated pressure an aqueous dispersion comprising thermoplastic resin particles containing a volatile foaming agent and an aqueous medium in a pressure vessel; releasing the dispersion from the pressure vessel into a space within a sealed low-pressure vessel wherein the pressure is lower than that in the pressure vessel, whereby expanding the thermoplastic resin particles to give pre-expanded particles; and simultaneously recovering the foaming agent volatilized from the thermoplastic resin particles by discharging the foaming agent out of the space in the low-pressure vessel with controlling the pressure in the low-pressure vessel to substantially a given pressure.
Claim 3
Dependent Claim
18 words
The process of Claim 1, wherein the given pressure in the low-pressure vessel is substantially a constant pressure.
Claim 4
Dependent Claim
63 words
The process of Claim 1, wherein the space in the low-pressure vessel is sealed with an aqueous medium which exists in the lower portion of the vessel and communicates with the outside of the vessel, and the pre-expanded particles are sunk under the aqueous medium and taken out of the vessel through the aqueous medium which communicates with the outside of the vessel.
Claim 5
Dependent Claim
59 words
The process of Claim 3, wherein the pre-expanded particles are sunk under the aqueous medium by a pushing plate which moves up and down along the inner surface of the separation wall of the low-pressure vessel so that the pre-expanded particles are taken out of the vessel through the aqueous medium which communicates with the outside of the vessel.
Claim 6
Dependent Claim
47 words
The process of Claim 3, wherein the pre-expanded particles are sunk under the aqueous medium by a rotary impeller provided in the low-pressure vessel so that the pre-expanded particles are taken out of the vessel through the aqueous medium which communicates with the outside of the vessel.
Claim 7
Independent Claim
193 words
An apparatus for preparing pre-expanded particles of a thermoplastic resin which comprises: a pressure vessel for heating under an elevated pressure an aqueous dispersion comprising thermoplastic resin particles containing a volatile foaming agent and an aqueous medium; a release line the one end of which communicates with the pressure vessel and which is provided with a release outlet at the other end thereof; a low-pressure vessel in which the thermoplastic resin particles containing the volatile foaming agent in the aqueous dispersion released thereinto through the release outlet is pre-expanded and the volatile foaming agent contained in the particles is volatilized, the space in the low-pressure vessel being sealed with an aqueous medium which exists in the lower portion of the vessel and communicates with the outside of the vessel; a means for discharging the volatilized foaming agent from the low-pressure vessel and recovering it with controlling the inner pressure of the low-pressure vessel to substantially a given pressure; and a means for sinking the pre-expanded particles under the aqueous medium in the low-pressure vessel to take them out of the vessel through the aqueous medium which communicates with the outside of the vessel.
Claim 8
Independent Claim
193 words
An apparatus for preparing pre-expanded particles of a thermoplastic resin which comprises: a pressure vessel for heating under an elevated pressure an aqueous dispersion comprising thermoplastic resin particles containing a volatile foaming agent and an aqueous medium; a release line the one end of which communicates with the pressure vessel and which is provided with a release outlet at the other end thereof; a low-pressure vessel in which the thermoplastic resin particles containing the volatile foaming agent in the aqueous dispersion released thereinto through the release outlet is pre-expanded and the volatile foaming agent contained in the particles is volatilized, the space in the low-pressure vessel being sealed with an aqueous medium which exists in the lower portion of the vessel and communicates with the outside of the vessel; a means for discharging the volatilized foaming agent from the low-pressure vessel and recovering it with controlling the inner pressure of the low-pressure vessel to substantially a given pressure; and a means for sinking the pre-expanded particles under the aqueous medium in the low-pressure vessel to take them out of the vessel through the aqueous medium which communicates with the outside of the vessel.
Claim 9
Dependent Claim
38 words
The apparatus of Claim 6, wherein the means for sinking and taking out the pre-expanded particles is a pushing plate which moves up and down along the inner surface of the separation wall of the low pressure vessel.
Claim 10
Dependent Claim
26 words
The apparatus of Claim 6, wherein the means for sinking and taking out the pre-expanded particles is 3 a rotary impeller provided in the low-pressure vessel.
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