CA2003073C - Polymeric material for the absorption of electromagnetic waves - Google Patents
Polymeric material for the absorption of electromagnetic waves Download PDFInfo
- Publication number
- CA2003073C CA2003073C CA002003073A CA2003073A CA2003073C CA 2003073 C CA2003073 C CA 2003073C CA 002003073 A CA002003073 A CA 002003073A CA 2003073 A CA2003073 A CA 2003073A CA 2003073 C CA2003073 C CA 2003073C
- Authority
- CA
- Canada
- Prior art keywords
- polymeric material
- absorption
- electromagnetic waves
- fact
- material according
- 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.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/08—Metals
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
- H01Q17/004—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems using non-directional dissipative particles, e.g. ferrite powders
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
- B32B2307/212—Electromagnetic interference shielding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2323/00—Polyalkenes
- B32B2323/04—Polyethylene
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2323/00—Polyalkenes
- B32B2323/16—EPDM, i.e. ethylene propylene diene monomer
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/16—Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
Abstract
Matériau polymère pour l'absorption d'ondes électromagnétiques. Matériau polymère pour l'absorption d'ondes électromagnétiques, caractérisé par le fait qu'il présente une structure composite comprenant: - un polymère à base de polyéthylène et d'EPDM, la proportion (en poids) de polyéthylène étant comprise entre 55% et 75%, - une charge de poudre de nickel dont la granulométrie est comprise entre 1 .mu.m et 200 .mu.m, avec un taux de charge en volume compris entre 5% et 35%.Polymeric material for the absorption of electromagnetic waves. Polymeric material for the absorption of electromagnetic waves, characterized in that it has a composite structure comprising: - a polymer based on polyethylene and EPDM, the proportion (by weight) of polyethylene being between 55% and 75%, - a charge of nickel powder with a particle size between 1 .mu.m and 200 .mu.m, with a charge rate by volume between 5% and 35%.
Description
MATÉRIAU POLYM~RE POUR L'ABSORPTION D'ONDES
ÉLECTROMAGNÉTIQUES
La présente invention concerne des matériaux polymères pour l'absorption d'ondes électromagnétiques, et notamment dans le domaine des ondes radar entre 8 et 12 GHz.
On sait que certains polymères peuvent être des absorbants d'ondes électromagnétiques: de telles indi-cations sont données par A. FELDBLUM (1981 -J.POL.SCI.19,173).
Ainsi ont été étudiées les propriétés d'absorption de structures composites constituées d'une matrice diélectrique et d'un conducteur organique tel que le polyacétylène, le polyparaphénylène et le polythiophène, vis-à-vis des ondes dont les fréquences sont comprises entre 100 MHz et 10 GHz.
Le problème est d'avoir à sa disposition des matériaux stables à l'air ambiant, et dans un domaine de température compris entre - 100°C et +100°C; il est habituellement considéré que leur conductivité 6 doit par exemple tendre vers 10-2 (ohm. cm) -1 pour qu' ils soient de bons absorbants; leur sensibilité aux variations de température doit être faible et leur permittivité relative par rapport à l'air ~ doit être la plus proche possible de la valeur 1 pour rendre minimale la réflexion de l'onde incidente.
Or les structures composites précitées, en particulier lorsqu'elles sont dopées pour répondre aux conditions de conductivité, ne répondent pas aux autres POLYMERIC MATERIAL FOR WAVE ABSORPTION
ELECTROMAGNETIC
The present invention relates to materials polymers for the absorption of electromagnetic waves, and especially in the field of radar waves between 8 and 12 GHz.
We know that certain polymers can be electromagnetic wave absorbers: such indi-cations are given by A. FELDBLUM (1981 -J.POL.SCI.19,173).
So the properties were studied of absorption of composite structures made up of a dielectric matrix and an organic conductor such as polyacetylene, polyparaphenylene and polythiophene, with respect to waves whose frequencies are between 100 MHz and 10 GHz.
The problem is to have at its disposal materials stable to ambient air, and in a field of temperature between - 100 ° C and + 100 ° C; he is usually considered that their conductivity 6 should by example tend towards 10-2 (ohm. cm) -1 so that they are good absorbents; their sensitivity to variations in temperature must be low and their relative permittivity relative to air ~ must be as close as possible to the value 1 to minimize the reflection of the wave incident.
Now the aforementioned composite structures, in especially when they are doped to respond to conductivity conditions, do not respond to others
2 conditions, notamment en ce qui concerne la stabilité à
l'air et aux variations de température. Conjointement il existe des structures métalliques composites produites commercialement; leur caractéristique est une excellente conductivité avec des densités très faibles de sorte que l'onde électromagnétique soit totalement réfléchie.
La présente invention a pour but d'éviter les inconvénients cités ci-dessus et de mettre en oeuvre des matériaux polymères particulièrement intéressants dans le domaine des ondes radar, car susceptibles de dissiper ces ondes.
La présente invention a pour objet un matériau polymère pour l'absorption d'ondes électromagnétiques, caractérisé par le fait qu'il présente une structure composite comprenant:
- un polymère à base de polyéthylène et d' EPDM, la proportion (en poids) de polyéthylène étant comprise entre 55~ et 75%, - une charge de poudre de nickel dont la granulométrie est comprise entre 1 ~m et 200 um, avec un taux de charge en volume compris entre 5% et 35~.
De préférence ladite granulométrie est comprise entre 3 um et 20 ~m avec une valeur optimale de 5 um.
De préférence ledit taux de charge est compris entre 15% et 25%, avec un taux optimal de 19~.
De préférence la proportion de polyéthylène dans la matrice est de l'ordre de 65~.
La présente invention a également pour objet une structure pour l'absorption des ondes électromagnétiques dans le domaine compris entre 8 et 12 GHz, caractérisée 2 conditions, in particular with regard to stability at air and temperature variations. Jointly it exist composite metallic structures produced commercially; their characteristic is excellent conductivity with very low densities so that the electromagnetic wave is fully reflected.
The object of the present invention is to avoid disadvantages mentioned above and to implement particularly interesting polymer materials in the radar wave domain, because likely to dissipate these waves.
The subject of the present invention is a material polymer for the absorption of electromagnetic waves, characterized by the fact that it has a structure composite comprising:
- a polymer based on polyethylene and EPDM, the proportion (by weight) of polyethylene being included between 55 ~ and 75%, - a charge of nickel powder, the particle size is between 1 ~ m and 200 µm, with a volume charge rate between 5% and 35 ~.
Preferably said particle size is understood between 3 µm and 20 ~ m with an optimal value of 5 µm.
Preferably said charge rate is understood between 15% and 25%, with an optimal rate of 19 ~.
Preferably the proportion of polyethylene in the matrix is of the order of 65 ~.
The present invention also relates to a structure for the absorption of electromagnetic waves in the range between 8 and 12 GHz, characterized
3 par le fait qu'elle comporte au moins une couche du matériau précité, avec une épaisseur maximale de 5 mm.
Une telle structure peut comporter en outre au moins une couche du polymère précité exempt de charge.
D'autres caractéristiques et avantages de la présente invention apparaîtront au cours de la description suivante de modes de réalisation donnés à titre illustratif mais non limitatif.
Dans le dessin annexé:
- La figure 1 montre une courbe du coefficient de réflexion R d'une couche absorbante selon l'invention en fonction de la fréquence f (GHz).
- La figure 2 est une vue analogue à la figure 1 pour une autre structure absorbante selon l'invention.
- La figure 3 montre l' influence du taux de charge c (%) en nickel dans le matériau selon l'invention, sur l'absorption A de ce matériau.
- La figure 4 montre l'influence de la granulométrie g (um) de la poudre de nickel dans le matériau selon l'invention, sur l'absorption A de ce matériau.
Pour préparer un exemple de matériau selon l'invention on opère de la façon suivante.
Dans un mélangeur préchauffé à 120°, on introduit de l'EPDM puis du polyéthylène, ce dernier se trouvant dans une proportion de 65% en poids. Après quatre minutes, on incorpore au mélange un antioxydant, puis le mélange obtenu est repris dans un mélangeur à cylindres à
160°C. On réalise une granulation puis une fusion à 160°C;
on incorpore ensuite une charge de nickel présentant une granulométrie de 5 ~Zm avec un taux de charge de 19%.
3a On homogénéise l'ensemble pendant quinze minutes et on réalise une nouvelle granulation. Les granulés sont ensuite fondus à 160°C, puis, après une nouvelle homo-généisation de quinze minutes, une nouvelle granulation est effectuée.
A partir de ces granulés on réalise une plaque de diamètre 250 mm et d'épaisseur 1,5 mm.
Pour cela on chauffe les granulés à 200°C
pendant quinze minutes, puis 3 minutes à 200°C sous 200 bars. Enfin on refroidit pendant cinq minutes sous 100 tonnes.
Une telle couche, dont la résistivité est de 0,5 ohm. cm, est déposée sur un support métallique; elle présente un taux d'absorption des ondes électromagnétiques très intéressant, comme le montre la figure 1. Dans cette figure apparaissent les fréquences f (GHz) en abscisses et le facteur de réflexion R en ordonnées.
Selon un autre exemple de mise en oeuvre, on dépose sur du métal une couche du polymère précédent non chargé et présentant une épaisseur de 500 ~.m, puis une couche de 1500 ~.m analogue à la couche dont les caractéristiques apparaissent dans la figure 1. La figure 2 montre les variations du facteur de réflexion R en fonction de la fréquence f.
Dans la figure 3 on a montré comment évolue l' absorption moyenne de la couche unitaire à la fréquence de 10 GHz (cf figure 1) lorsque le taux de charge en nickel varie de 5 % à 35 % . On a noté en abscisses le taux de charge en volume c % et en ordonnées l'absorption en décibels.
3b Dans la figure 4 le taux de charge est de 19~
mais on modifie la granulométrie g de la poudre de nickel entre 0 et 200 gym. La fréquence est toujours 10 GHz. En abscisses figurent les granulométries g en microns et en ordonnées le coefficient d'absorption A en décibels.
Bien entendu l'invention n'est pas limitée aux exemples qui viennent d'être décrits. 3 by the fact that it comprises at least one layer of the aforementioned material, with a maximum thickness of 5 mm.
Such a structure may further include at minus one layer of the aforementioned polymer free of charge.
Other features and advantages of the present invention will appear during the description following of embodiments given as illustrative but not limiting.
In the attached drawing:
- Figure 1 shows a curve of the coefficient of reflection R of an absorbent layer according to the invention in function of frequency f (GHz).
- Figure 2 is a view similar to Figure 1 for a another absorbent structure according to the invention.
- Figure 3 shows the influence of the charge rate c (%) of nickel in the material according to the invention, on the absorption A of this material.
- Figure 4 shows the influence of the particle size g (um) of nickel powder in the material according to the invention, on the absorption A of this material.
To prepare an example material according to the invention operates as follows.
In a mixer preheated to 120 °, we introduces EPDM then polyethylene, the latter found in a proportion of 65% by weight. After four minutes, we incorporate an antioxidant into the mixture, then mixture obtained is taken up in a cylinder mixer with 160 ° C. Granulation is carried out followed by melting at 160 ° C .;
then incorporating a nickel charge having a particle size of 5 ~ Zm with a charge rate of 19%.
3a The whole is homogenized for fifteen minutes and a new granulation is carried out. The granules are then melted at 160 ° C, then, after another homo-fifteen minutes of genitization, a new granulation is done.
From these granules, a plate is produced.
250 mm in diameter and 1.5 mm thick.
For this, the granules are heated to 200 ° C.
for fifteen minutes, then 3 minutes at 200 ° C under 200 bars. Finally we cool for five minutes under 100 tonnes.
Such a layer, the resistivity of which is 0.5 ohm. cm, is deposited on a metal support; she has an absorption rate of electromagnetic waves very interesting, as shown in Figure 1. In this figure the frequencies f (GHz) appear on the abscissa and the reflection factor R on the ordinate.
According to another example of implementation, we deposits on metal a layer of the preceding polymer not loaded and having a thickness of 500 ~ .m, then a 1500 ~ .m layer similar to the layer whose features appear in Figure 1. Figure 2 shows the variations of the reflection factor R in frequency function f.
In figure 3 we showed how evolves the average absorption of the unitary layer at the frequency 10 GHz (see Figure 1) when the charge rate in nickel ranges from 5% to 35%. We have noted on the abscissa the rate load in volume c% and on the ordinate the absorption in decibels.
3b In Figure 4 the charge rate is 19 ~
but the particle size g of the nickel powder is modified between 0 and 200 gym. The frequency is always 10 GHz. In abscissas are the particle sizes g in microns and ordered the absorption coefficient A in decibels.
Of course, the invention is not limited to examples which have just been described.
Claims (8)
- un polymère à base de polyéthylène et d'EPDM, le polyéthylène constituant une proportion en poids comprise entre 55 % et 75 %, - une charge de poudre de nickel ayant une granulométrie comprise entre 1 µm et 200 µm, avec un taux de charge en volume compris entre 5% et 35%. 1. Polymeric material to absorb electromagnetic waves, characterized by the fact that it has a composite structure comprising:
- a polymer based on polyethylene and EPDM, polyethylene constituting a proportion by weight included between 55% and 75%, - a charge of nickel powder having a particle size between 1 µm and 200 µm, with a charge rate of volume between 5% and 35%.
par le fait que ladite granulométrie est comprise entre 3 µm et 20 µm. 2. Polymeric material according to claim 1, characterized by the fact that said particle size is between 3 μm and 20 µm.
par le fait que ladite granulométrie est de l'ordre de 5 µm. 3. Polymeric material according to claim 1, characterized by the fact that said particle size is of the order of 5 μm.
par le fait que ledit taux de charge est de l'ordre de 19%. 5. Polymeric material according to claim 4, characterized by the fact that said charge rate is of the order of 19%.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8814939A FR2736647B1 (en) | 1988-11-17 | 1988-11-17 | POLYMERIC MATERIAL FOR THE ABSORPTION OF ELECTROMAGNETIC WAVES |
FR8814939 | 1988-11-17 |
Publications (2)
Publication Number | Publication Date |
---|---|
CA2003073A1 CA2003073A1 (en) | 1996-10-11 |
CA2003073C true CA2003073C (en) | 2000-01-18 |
Family
ID=9371930
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002003073A Expired - Fee Related CA2003073C (en) | 1988-11-17 | 1989-11-16 | Polymeric material for the absorption of electromagnetic waves |
Country Status (8)
Country | Link |
---|---|
BE (1) | BE1011412A4 (en) |
CA (1) | CA2003073C (en) |
DE (1) | DE3936196C2 (en) |
FR (1) | FR2736647B1 (en) |
GB (1) | GB2307106B (en) |
IT (1) | IT1267134B1 (en) |
NL (1) | NL8902826A (en) |
NO (1) | NO306888B1 (en) |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2996710A (en) * | 1945-09-20 | 1961-08-15 | Du Pont | Electromagnetic radiation absorptive article |
JPS54124298A (en) * | 1978-03-20 | 1979-09-27 | Tdk Corp | Material for radio wave absorber |
JPS5887142A (en) * | 1981-11-20 | 1983-05-24 | Showa Denko Kk | Polyolefin composition |
JPS60127366A (en) * | 1983-12-15 | 1985-07-08 | Tounen Sekiyu Kagaku Kk | Thermoplastic resin composition |
-
1988
- 1988-11-17 FR FR8814939A patent/FR2736647B1/en not_active Expired - Fee Related
-
1989
- 1989-10-31 DE DE3936196A patent/DE3936196C2/en not_active Expired - Fee Related
- 1989-11-03 GB GB8924800A patent/GB2307106B/en not_active Expired - Fee Related
- 1989-11-07 IT IT06795689A patent/IT1267134B1/en active IP Right Grant
- 1989-11-08 NO NO894439A patent/NO306888B1/en not_active IP Right Cessation
- 1989-11-15 NL NL8902826A patent/NL8902826A/en active Search and Examination
- 1989-11-16 CA CA002003073A patent/CA2003073C/en not_active Expired - Fee Related
- 1989-11-16 BE BE8901210A patent/BE1011412A4/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
GB8924800D0 (en) | 1996-12-18 |
DE3936196C2 (en) | 2000-02-03 |
IT8967956A1 (en) | 1991-05-07 |
FR2736647A1 (en) | 1997-01-17 |
GB2307106A (en) | 1997-05-14 |
FR2736647B1 (en) | 1998-05-15 |
NO894439L (en) | 1996-08-13 |
NL8902826A (en) | 1997-08-01 |
NO306888B1 (en) | 2000-01-03 |
BE1011412A4 (en) | 1999-09-07 |
DE3936196A1 (en) | 1997-02-20 |
IT8967956A0 (en) | 1989-11-07 |
GB2307106B (en) | 1998-01-07 |
CA2003073A1 (en) | 1996-10-11 |
IT1267134B1 (en) | 1997-01-24 |
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