EP0632522A1 - Dielectric lens for an antenna and manufacturing process thereof - Google Patents

Dielectric lens for an antenna and manufacturing process thereof Download PDF

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Publication number
EP0632522A1
EP0632522A1 EP94110099A EP94110099A EP0632522A1 EP 0632522 A1 EP0632522 A1 EP 0632522A1 EP 94110099 A EP94110099 A EP 94110099A EP 94110099 A EP94110099 A EP 94110099A EP 0632522 A1 EP0632522 A1 EP 0632522A1
Authority
EP
European Patent Office
Prior art keywords
radome
dielectric lens
antenna
specified
dielectric
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP94110099A
Other languages
German (de)
French (fr)
Other versions
EP0632522B1 (en
Inventor
Keizo C/O Murata Manufacturing Co. Ltd Yamamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Murata Manufacturing Co Ltd
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Murata Manufacturing Co Ltd
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Filing date
Publication date
Application filed by Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Publication of EP0632522A1 publication Critical patent/EP0632522A1/en
Application granted granted Critical
Publication of EP0632522B1 publication Critical patent/EP0632522B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/02—Refracting or diffracting devices, e.g. lens, prism
    • H01Q15/08—Refracting or diffracting devices, e.g. lens, prism formed of solid dielectric material

Definitions

  • the present invention relates to a dielectric lens, and more particularly to a dielectric lens used as an element of an antenna for receiving microwave for communication and broadcasting.
  • a dielectric lens used as an element of an antenna for receiving microwave of 5GHz or more is conventionally produced by: mixing a resin, for example, polypropylene, polyethylene, polystyrene or the like, with ceramic powder, which acts as a foaming agent and as a dielectric constant conditioner; and molding the mixture into a dome.
  • a resin for example, polypropylene, polyethylene, polystyrene or the like
  • ceramic powder which acts as a foaming agent and as a dielectric constant conditioner
  • the dielectric lens is molded to be thick and accordingly to be heavy. For example, if a mixture of polypropylene and ceramic powder is molded into a dome which is about 180mm in diameter and about 76mm in height, the weight will be about 1kg. Thus, a large quantity of resin is necessary, and the cost of the dielectric lens is high.
  • the thickly molded dielectric lens is likely to have a defect such as a sink mark and a swirl mark on the surface (radome layer) and a void inside.
  • the defect can be fairly avoided by adopting injection compression molding.
  • the injection compression molding requires a mold of a complicated structure and expensive facilities. Even in the injection compression molding, it is difficult to completely prevent occurrence of a sink mark, a swirl mark and a void. Further, a product by the injection compression molding has residual stress, which is a cause of deflection.
  • An object of the present invention is to provide a light and inexpensive dielectric lens which does not have a defect such as a sink mark, a swirl mark and a void.
  • Another object of the present invention is to provide a simple manufacturing process of a dielectric lens which does not require expensive facilities.
  • a dielectric lens according to the present invention comprises a radome which is molded as a dome shell of a specified size, and a foamy body with a specified dielectric constant which is mounted in the radome.
  • the foamy body consists essentially of preexpanded beads.
  • a specified quantity of preexpanded beads are deposited in the radome, and the radome is closed with a lid.
  • the preexpanded beads are deposited in a mold and are fusion-molded into a body which has a curved surface identical with the inner surface of the radome. Then, the fusion-molded body is mounted in the radome, and the radome is closed with a lid.
  • the radome and the foamy body are molded separately, and the produced lens is less likely to have a sink mark, a swirl mark and/or a void compared with a conventional dielectric lens produced by integral molding. Also, since preexpanded beads are used for the foamy body, only a small quantity of resin is necessary, thereby lessening the weight.
  • the radome is formed by ordinary thinwall injection molding, and the foamy body is formed by ordinary foaming. Therefore, such expensive facilities as to be used for injection compression molding are not required, and the cost for facilities is low.
  • a dielectric lens according to the present invention and a manufacturing process thereof are hereinafter described with reference to the accompanying drawings.
  • numeral 1 denotes a radome
  • numeral 5 denotes a lid
  • numeral 10 denotes a foamy body.
  • the radome 1 is molded as a dome shell of a specified size.
  • the foamy body 10 has a curved surface which is identical with the inner surface of the radome 1 such that the foamy body 10 will be mounted in the radome 1 with no space in-between.
  • the foamy body 10 is produced by the following process.
  • an aliphatic hydrocarbon for example, hexane, butane, pentane or the like, is impregnated into polymer particles of polystyrene.
  • a dielectric constant conditioner is added, and the polystyrene is preexpanded.
  • polystyrene preexpanded beads are obtained.
  • the preexpanded beads are deposited in a mold and are fusion-molded.
  • the inner surface of the mold is identical with the inner surface of the radome 1 such that the fusion-molded body 10 can be mounted in the radome 1 with no space in-between.
  • the radome 1 and the lid 5 are made thin, out of the same polystyrene used for the foamy body 10 by a conventional method such as injection molding.
  • the foamy body 10 is mounted in the radome 1, and the lid 5 is set at the opening of the radome 1.
  • a dielectric lens is assembled.
  • the radome 1 and the lid 5 are preferably bonded airtight by an adhesive or by ultrasonic welding.
  • the radome 1 is desirably thin for a high antenna gain and is made to be 2mm, and more desirably 1mm or less, in thickness. In point of the antenna gain, it is further preferred that the space between the radome 1 and the foamy body 10 is not more than 0.5mm. If a pigment such as titanium oxide is added to the material of the radome 1, the radome 1 will absorb ultraviolet rays, which helps the foamy body 10 maintain its characteristic and lengthens the life of the lens.
  • the followings are exemplary constituents of the foamy body 10.
  • resin polystyrene at a mixing ratio by weight of 100 dielectric constant conditioner: calcium titanate at a mixing ratio by weight of 60 foaming agent: butane
  • dielectric constant conditioner and the foaming agent were added to the resin, and the resin was preexpanded at an expansion ratio of 15. Then, the preexpanded resin was fusion-molded.
  • a foamy body 10 which has a dielectric constant of 1.5 and has a weight of 250g was produced.
  • the preexpanded beads are deposited directly in the radome 1, and the radome 1 is closed with the lid 5.
  • the constituents of the materials of the radome 1, the lid 5 and the foamy body 10 are not limited to those described above.
  • the resin polystyrene, polypropylene, polyethylene, etc. can be used.
  • the foaming agent butane, pentane, etc. can be used.
  • the dielectric constant conditioner calcium titanate, barium titanate, etc. can be used.

Abstract

A dielectric lens which consists of a radome (1) which is a dome shell, a lid (5), and a foamy body (10) produced by fusion-molding of preexpanded beads. The foamy body is mounted in the radome, and the radome is closed with the lid.

Description

    [Technical Field]
  • The present invention relates to a dielectric lens, and more particularly to a dielectric lens used as an element of an antenna for receiving microwave for communication and broadcasting.
    • [Background Art]
  • A dielectric lens used as an element of an antenna for receiving microwave of 5GHz or more is conventionally produced by: mixing a resin, for example, polypropylene, polyethylene, polystyrene or the like, with ceramic powder, which acts as a foaming agent and as a dielectric constant conditioner; and molding the mixture into a dome. In the molding, the surface of the dielectric lens is solidified, and a radome layer is formed. The radome layer protects the inner foamy body from weathering and reinforces the foamy body.
  • In the conventional manufacturing process, the dielectric lens is molded to be thick and accordingly to be heavy. For example, if a mixture of polypropylene and ceramic powder is molded into a dome which is about 180mm in diameter and about 76mm in height, the weight will be about 1kg. Thus, a large quantity of resin is necessary, and the cost of the dielectric lens is high.
  • The thickly molded dielectric lens is likely to have a defect such as a sink mark and a swirl mark on the surface (radome layer) and a void inside. The defect can be fairly avoided by adopting injection compression molding. However, the injection compression molding requires a mold of a complicated structure and expensive facilities. Even in the injection compression molding, it is difficult to completely prevent occurrence of a sink mark, a swirl mark and a void. Further, a product by the injection compression molding has residual stress, which is a cause of deflection.
    • [Disclosure of the Invention]
  • An object of the present invention is to provide a light and inexpensive dielectric lens which does not have a defect such as a sink mark, a swirl mark and a void.
  • Another object of the present invention is to provide a simple manufacturing process of a dielectric lens which does not require expensive facilities.
  • In order to attain the above objects, a dielectric lens according to the present invention comprises a radome which is molded as a dome shell of a specified size, and a foamy body with a specified dielectric constant which is mounted in the radome.
  • The foamy body consists essentially of preexpanded beads. A specified quantity of preexpanded beads are deposited in the radome, and the radome is closed with a lid. Alternatively, the preexpanded beads are deposited in a mold and are fusion-molded into a body which has a curved surface identical with the inner surface of the radome. Then, the fusion-molded body is mounted in the radome, and the radome is closed with a lid.
  • According to the present invention, the radome and the foamy body are molded separately, and the produced lens is less likely to have a sink mark, a swirl mark and/or a void compared with a conventional dielectric lens produced by integral molding. Also, since preexpanded beads are used for the foamy body, only a small quantity of resin is necessary, thereby lessening the weight. The radome is formed by ordinary thinwall injection molding, and the foamy body is formed by ordinary foaming. Therefore, such expensive facilities as to be used for injection compression molding are not required, and the cost for facilities is low.
    • [Brief Description of the Drawings]
  • These and other objects and features of the present invention will be apparent from the following description in connection with the accompanying drawings, in which:
    • Fig. 1 is an explosive perspective view of a dielectric lens which is an embodiment of the present invention; and
    • Fig. 2 is a sectional view of the assembled dielectric lens.
    [Best Mode for Carrying out the Invention]
  • A dielectric lens according to the present invention and a manufacturing process thereof are hereinafter described with reference to the accompanying drawings.
  • In Figs. 1 and 2, numeral 1 denotes a radome, numeral 5 denotes a lid, and numeral 10 denotes a foamy body. The radome 1 is molded as a dome shell of a specified size. The foamy body 10 has a curved surface which is identical with the inner surface of the radome 1 such that the foamy body 10 will be mounted in the radome 1 with no space in-between.
  • The foamy body 10 is produced by the following process. In a water disperse system in an autoclave, an aliphatic hydrocarbon, for example, hexane, butane, pentane or the like, is impregnated into polymer particles of polystyrene. Further, a dielectric constant conditioner is added, and the polystyrene is preexpanded. By the preexpansion, polystyrene preexpanded beads are obtained. Next, the preexpanded beads are deposited in a mold and are fusion-molded. The inner surface of the mold is identical with the inner surface of the radome 1 such that the fusion-molded body 10 can be mounted in the radome 1 with no space in-between.
  • The radome 1 and the lid 5 are made thin, out of the same polystyrene used for the foamy body 10 by a conventional method such as injection molding.
  • The foamy body 10 is mounted in the radome 1, and the lid 5 is set at the opening of the radome 1. Thus, a dielectric lens is assembled. The radome 1 and the lid 5 are preferably bonded airtight by an adhesive or by ultrasonic welding. The radome 1 is desirably thin for a high antenna gain and is made to be 2mm, and more desirably 1mm or less, in thickness. In point of the antenna gain, it is further preferred that the space between the radome 1 and the foamy body 10 is not more than 0.5mm. If a pigment such as titanium oxide is added to the material of the radome 1, the radome 1 will absorb ultraviolet rays, which helps the foamy body 10 maintain its characteristic and lengthens the life of the lens.
  • The followings are exemplary constituents of the foamy body 10.
       resin: polystyrene at a mixing ratio by weight of 100
       dielectric constant conditioner: calcium titanate at a mixing ratio by weight of 60
       foaming agent: butane
       The dielectric constant conditioner and the foaming agent were added to the resin, and the resin was preexpanded at an expansion ratio of 15. Then, the preexpanded resin was fusion-molded. As a result, a foamy body 10 which has a dielectric constant of 1.5 and has a weight of 250g was produced.
  • It is possible to eliminate the fusion-molding process. The preexpanded beads are deposited directly in the radome 1, and the radome 1 is closed with the lid 5.
  • The constituents of the materials of the radome 1, the lid 5 and the foamy body 10 are not limited to those described above. As the resin, polystyrene, polypropylene, polyethylene, etc. can be used. As the foaming agent, butane, pentane, etc. can be used. As the dielectric constant conditioner, calcium titanate, barium titanate, etc. can be used.
  • Although the present invention has been described in connection with the preferred embodiment, it is to be noted that various changes and modifications are possible to those who are skilled in the art. Such changes and modifications are to be understood as being within the scope of the present invention.

Claims (6)

  1. A dielectric lens for an antenna, comprising:
       a radome which is a dome shell of a specified size; and
       an expanded material which is deposited in the radome, the expanded material having a specified dielectric constant.
  2. A dielectric lens for an antenna as claimed in claim 1, wherein the expanded material is shaped into a dome whose curved surface is substantially identical with an inner surface of the radome.
  3. A dielectric lens for an antenna as claimed in claim 1, wherein the expanded material is preexpanded beads.
  4. A dielectric lens for an antenna as claimed in claim 1, wherein the radome contains a ultraviolet-ray absorbing agent.
  5. A method for producing a dielectric lens for an antenna, the method comprising the steps of:
       molding a radome as a dome shell of a specified size;
       forming preexpanded beads with a specified dielectric constant;
       fusion-molding the preexpanded beads into a dome whose curved surface is substantially identical with an inner surface of the radome; and
       mounting the fusion-molded dome in the radome and setting a lid at an opening of the radome.
  6. A method for producing a dielectric lens for an antenna, the method comprising the steps of:
       molding a radome as a dome shell of a specified size;
       forming preexpanded beads with a specified dielectric constant; and
       depositing a specified quantity of the preexpanded beads in the radome and setting a lid at an opening of the radome.
EP94110099A 1993-06-30 1994-06-29 Dielectric lens for an antenna and manufacturing process thereof Expired - Lifetime EP0632522B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP5161006A JPH0722834A (en) 1993-06-30 1993-06-30 Dielectric lens for antenna and its production
JP161006/93 1993-06-30

Publications (2)

Publication Number Publication Date
EP0632522A1 true EP0632522A1 (en) 1995-01-04
EP0632522B1 EP0632522B1 (en) 1999-02-03

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Country Status (3)

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EP (1) EP0632522B1 (en)
JP (1) JPH0722834A (en)
DE (1) DE69416347T2 (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0903807A2 (en) * 1997-09-18 1999-03-24 Robert Bosch Gmbh Method for producing a lens for an antenna
FR2777117A1 (en) * 1998-04-06 1999-10-08 Alsthom Cge Alcatel MULTI-LAYERED FOCUSING SPHERICAL LENS
EP0969550A1 (en) * 1998-06-29 2000-01-05 Murata Manufacturing Co., Ltd. Dielectric lens antenna and radio equipment including the same
WO2000076027A1 (en) * 1999-06-07 2000-12-14 Spike Broadband Systems, Inc. Axially symmetric gradient lenses and antenna systems employing same
EP1089377A2 (en) * 1999-09-30 2001-04-04 Kabushiki Kaisha Toshiba Antenna apparatus
FR2804249A1 (en) * 2000-01-26 2001-07-27 Thomson Multimedia Sa DEVICE FOR TRANSMITTING AND / OR RECEIVING ELECTROMAGNETIC WAVES COMPRISING A LENS HAVING A CONFORMED VOLUME OF DIELECTRIC MATERIAL
EP1653559A1 (en) * 2003-07-31 2006-05-03 Sumitomo Electric Industries, Ltd. Luneberg lens and antenna device using the same
EP1750329A1 (en) * 2005-07-30 2007-02-07 Hella KG Hueck & Co. Radome for a vehicle radar system and method of manufacturing a radome
WO2016113328A1 (en) 2015-01-14 2016-07-21 Synthos S.A. Use of a mineral having perovskite structure in vinyl aromatic polymer foam
EP3245247B1 (en) 2015-01-14 2018-12-26 Synthos S.A. Combination of silica and graphite and its use for decreasing the thermal conductivity of vinyl aromatic polymer foam
US10639829B2 (en) 2015-01-14 2020-05-05 Synthos S.A. Process for the production of expandable vinyl aromatic polymer granulate having decreased thermal conductivity
US10961154B2 (en) 2015-01-14 2021-03-30 Synthos S.A. Geopolymer composite and expandable vinyl aromatic polymer granulate and expanded vinyl aromatic polymer foam comprising the same

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JP2001279014A (en) * 2000-03-31 2001-10-10 Achilles Corp Dielectric expansion-molded product having improved dimensional stability
JP3521845B2 (en) * 2000-05-12 2004-04-26 日本電気株式会社 Dielectric lens and method of manufacturing the same
CN1759505B (en) * 2003-03-11 2010-05-26 住友电气工业株式会社 Luneberg lens and process for producing the same
US7301504B2 (en) 2004-07-14 2007-11-27 Ems Technologies, Inc. Mechanical scanning feed assembly for a spherical lens antenna
CN104149228B (en) * 2014-07-08 2016-08-24 中国电子科技集团公司第二十研究所 The integrated molding mould of a kind of fiberglass radome and forming method

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US3917773A (en) * 1973-12-26 1975-11-04 Us Navy Method for fabricating a shaped dielectric antenna lens
US4288337A (en) * 1977-05-02 1981-09-08 Tokyo Keiki Company Limited Lightweight materials having a high dielectric constant and their method of manufacture
US4482513A (en) * 1981-03-10 1984-11-13 General Dynamics, Pomona Division Method of molding foam/aluminum flake microwave lenses
US4640280A (en) * 1985-08-12 1987-02-03 Rca Corporation Microwave hyperthermia with dielectric lens focusing
WO1989008932A1 (en) * 1988-02-23 1989-09-21 The Secretary Of State For Defence In Her Britanni A solid dielectric lens aerial
WO1993010572A1 (en) * 1991-11-19 1993-05-27 Thomson Consumer Electronics S.A. Dielectric material for antennas

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GB8603206D0 (en) * 1986-02-10 1986-03-19 Ca Minister Nat Defence Projectile
JPS63300608A (en) * 1987-05-29 1988-12-07 Mitsubishi Electric Corp Antenna system
JPH0380604A (en) * 1989-08-23 1991-04-05 Murata Mfg Co Ltd Dielectric lens antenna
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JP2738143B2 (en) * 1990-10-31 1998-04-08 日本電気株式会社 Satellite receiving antenna
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Publication number Priority date Publication date Assignee Title
US3917773A (en) * 1973-12-26 1975-11-04 Us Navy Method for fabricating a shaped dielectric antenna lens
US4288337A (en) * 1977-05-02 1981-09-08 Tokyo Keiki Company Limited Lightweight materials having a high dielectric constant and their method of manufacture
US4482513A (en) * 1981-03-10 1984-11-13 General Dynamics, Pomona Division Method of molding foam/aluminum flake microwave lenses
US4640280A (en) * 1985-08-12 1987-02-03 Rca Corporation Microwave hyperthermia with dielectric lens focusing
WO1989008932A1 (en) * 1988-02-23 1989-09-21 The Secretary Of State For Defence In Her Britanni A solid dielectric lens aerial
WO1993010572A1 (en) * 1991-11-19 1993-05-27 Thomson Consumer Electronics S.A. Dielectric material for antennas

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0903807A3 (en) * 1997-09-18 2000-07-05 Robert Bosch Gmbh Method for producing a lens for an antenna
EP0903807A2 (en) * 1997-09-18 1999-03-24 Robert Bosch Gmbh Method for producing a lens for an antenna
US6229500B1 (en) 1998-04-06 2001-05-08 Alcatel Multilayer focusing spherical lens
WO1999052180A1 (en) * 1998-04-06 1999-10-14 Alcatel Multilayer focusing spherical lens
EP0949710A1 (en) * 1998-04-06 1999-10-13 Alcatel Spherical multilayer focalising lens
FR2777117A1 (en) * 1998-04-06 1999-10-08 Alsthom Cge Alcatel MULTI-LAYERED FOCUSING SPHERICAL LENS
EP0969550A1 (en) * 1998-06-29 2000-01-05 Murata Manufacturing Co., Ltd. Dielectric lens antenna and radio equipment including the same
US6175335B1 (en) * 1998-06-29 2001-01-16 Murata Manufacturing Co., Ltd. Dielectric lens antenna having heating body and radio equipment including the same
WO2000076027A1 (en) * 1999-06-07 2000-12-14 Spike Broadband Systems, Inc. Axially symmetric gradient lenses and antenna systems employing same
EP1089377A2 (en) * 1999-09-30 2001-04-04 Kabushiki Kaisha Toshiba Antenna apparatus
EP1089377A3 (en) * 1999-09-30 2003-10-29 Kabushiki Kaisha Toshiba Antenna apparatus
FR2804249A1 (en) * 2000-01-26 2001-07-27 Thomson Multimedia Sa DEVICE FOR TRANSMITTING AND / OR RECEIVING ELECTROMAGNETIC WAVES COMPRISING A LENS HAVING A CONFORMED VOLUME OF DIELECTRIC MATERIAL
EP1120857A3 (en) * 2000-01-26 2001-09-19 THOMSON multimedia Device for emitting and/or receiving electromagnetic waves comprising a lens made of a shaped volume of dielectric material
US6426731B2 (en) 2000-01-26 2002-07-30 Thomson Licensing, Sa Device for emitting and/or receiving electromagnetic waves comprising a lens made of a shaped volume of dielectric material
EP1653559A1 (en) * 2003-07-31 2006-05-03 Sumitomo Electric Industries, Ltd. Luneberg lens and antenna device using the same
EP1653559A4 (en) * 2003-07-31 2006-11-15 Sumitomo Electric Industries Luneberg lens and antenna device using the same
EP1750329A1 (en) * 2005-07-30 2007-02-07 Hella KG Hueck & Co. Radome for a vehicle radar system and method of manufacturing a radome
WO2016113328A1 (en) 2015-01-14 2016-07-21 Synthos S.A. Use of a mineral having perovskite structure in vinyl aromatic polymer foam
CN107428979A (en) * 2015-01-14 2017-12-01 西索斯公司 Use of the mineral matter with perovskite structure in vinyl aromatic polymers foam
EP3245242B1 (en) 2015-01-14 2018-08-29 Synthos S.A. Use of a mineral having perovskite structure in vinyl aromatic polymer foam
EP3245247B1 (en) 2015-01-14 2018-12-26 Synthos S.A. Combination of silica and graphite and its use for decreasing the thermal conductivity of vinyl aromatic polymer foam
US10639829B2 (en) 2015-01-14 2020-05-05 Synthos S.A. Process for the production of expandable vinyl aromatic polymer granulate having decreased thermal conductivity
US10808093B2 (en) 2015-01-14 2020-10-20 Synthos S.A. Combination of silica and graphite and its use for decreasing the thermal conductivity of vinyl aromatic polymer foam
US10961154B2 (en) 2015-01-14 2021-03-30 Synthos S.A. Geopolymer composite and expandable vinyl aromatic polymer granulate and expanded vinyl aromatic polymer foam comprising the same
CN107428979B (en) * 2015-01-14 2021-06-08 西索斯公司 Use of mineral substances with perovskite structure in vinylaromatic polymeric foams
US11267170B2 (en) 2015-01-14 2022-03-08 Synthos S.A. Process for the production of expandable vinyl aromatic polymer granulate having decreased thermal conductivity
US11447614B2 (en) 2015-01-14 2022-09-20 Synthos S.A. Combination of silica and graphite and its use for decreasing the thermal conductivity of vinyl aromatic polymer foam
US11708306B2 (en) 2015-01-14 2023-07-25 Synthos S.A. Geopolymer composite and expandable vinyl aromatic polymer granulate and expanded vinyl aromatic polymer foam comprising the same
US11859066B2 (en) 2015-01-14 2024-01-02 Synthos S.A. Use of a mineral having perovskite structure in vinyl aromatic polymer foam

Also Published As

Publication number Publication date
EP0632522B1 (en) 1999-02-03
DE69416347T2 (en) 1999-07-15
DE69416347D1 (en) 1999-03-18
JPH0722834A (en) 1995-01-24

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