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WO1996041355A1 - Composition electriquement non lineaire et dispositif - Google Patents

Composition electriquement non lineaire et dispositif Download PDF

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Publication number
WO1996041355A1
WO1996041355A1 PCT/US1996/009113 US9609113W WO9641355A1 WO 1996041355 A1 WO1996041355 A1 WO 1996041355A1 US 9609113 W US9609113 W US 9609113W WO 9641355 A1 WO9641355 A1 WO 9641355A1
Authority
WO
WIPO (PCT)
Prior art keywords
composition
polymeric component
electrode
magnetic
resistivity
Prior art date
Application number
PCT/US1996/009113
Other languages
English (en)
Inventor
William H. Simendinger, Iii
Rudolf R. Bukovnik
Chi Suk Yom
Original Assignee
Raychem Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Raychem Corporation filed Critical Raychem Corporation
Publication of WO1996041355A1 publication Critical patent/WO1996041355A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
    • H01C7/12—Overvoltage protection resistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/027—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient consisting of conducting or semi-conducting material dispersed in a non-conductive organic material

Definitions

  • This invention relates to electrically non-linear compositions and to devices comprising such compositions.
  • compositions are commonly used to protect electrical equipment and circuitry. Such compositions often exhibit non-linear electrical resistivity, decreasing in resistance when exposed to a voltage that exceeds a threshold value. This value is known as the breakdown voltage.
  • Compositions exhibiting non-linear electrical behavior are disclosed in U.S. Patent Nos. 4,977,357 (Shrier) and 5,294,374 (Martinez et al), in International Application No. PCT/US95/06867 (Simendinger et al, filed May 30, 1995), and in U.S. Patent Application No. 08/046,059 (Debbaut et al, filed April 10, 1993). It is common to use such compositions in devices which provide secondary or backup protection for other protection devices, i.e.
  • compositions generally are not able to accommodate the energy levels required to act as primary protection in a way that devices such gas discharge tubes do. Furthermore, such compositions often exhibit a decrease in breakdown voltage on successive impulses, making them unstable for repeated use.
  • an electrically non-linear composition with high energy-carrying capability and improved stability during breakdown can be prepared by selecting a combination of particulate fillers, dispersing the fillers in a polymeric component, and then aligning the fillers in discrete regions throughout the polymeric component.
  • this invention provides an electrically non-linear composition which comprises
  • a polymeric component (2) a first paniculate filler which is magnetic and electrically conductive, and
  • a second particulate filler which is magnetic and has a resistivity of at least 1 x 10 4 ohm-cm
  • said first and second fillers being aligned in discrete regions in the polymeric component.
  • compositions of the first aspect of the invention can be used to prepare electrical devices which themselves act to protect electrical components, e.g. act as a primary protection device in a telecommunications circuit rather than a backup protection device, and thus replace crowbar devices such as gas discharge tubes and thyristors.
  • this invention provides an electrical device which comprises
  • first and second fillers being aligned in discrete regions extending through the resistive element from the first electrode to the second electrode.
  • Figure 1 is a schematic cross-sectional view of an electrical device of the invention
  • Figure 2 is a schematic cross-sectional view of another electrical device of the invention.
  • Figure 3 is a schematic cross-sectional view of a test fixture used to test a device of the invention.
  • Figures 4, 5, 6a, and 6b are graphs of breakdown voltage as a function of test number for devices of the invention.
  • composition of the invention exhibits electrically non-linear behavior.
  • non-linear means that the composition is substantially electrically
  • non-conductive i.e. has a resistivity of more than 10 ohm-cm, and preferably more than 10 8 ohm-cm, when an applied voltage is less than the impulse breakdown voltage, but then becomes electrically conductive, i.e. has a resistivity of substantially less than 10 ohm-cm, when the applied voltage is equal to or greater than the impulse breakdown voltage.
  • the composition have a resistivity in the "non-conducting" state of more than 10 ohm-cm, e.g. 10 ohm-cm, and a resistivity in the "conducting" state of less than 10 ohm-cm.
  • the electrically non-linear composition comprises a polymeric component which acts as a matrix to contain the first, second, and optional third paniculate fillers.
  • the polymeric component may be any appropriate polymer, e.g. a thermoplastic material such as a polyolefin, a fluoropolymer, a polyamide, a polycarbonate, or a polyester; a thermosetting material such as an epoxy; an elastomer (including silicone elastomers, acrylates, polyurethanes, polyesters, and liquid ethylene/propylene/diene monomers); a grease; or a gel. It is preferred that the polymeric component be a curable material, i.e.
  • the polymeric component is generally present in an amount of 30 to 99.8%, preferably 35 to 95%, particularly 40 to 90% by volume of the total composition.
  • Suitable extender fluids include mineral oil, vegetable oil, paraffinic oil, silicone oil, plasticizer such as trimellitate, or a mixture of these, generally in an amount of 30 to 90% by volume of the total weight of the gel without filler.
  • the gel may be a thermosetting gel, e.g. silicone gel, in which the crosslinks are formed through the use of multifunctional crosslinking agents, or a thermoplastic gel, in which microphase separation of domains serves as junction points. Disclosures of gels which may be suitable as the polymeric component in the composition are found in U.S. Patent Nos.4,600,261 (Debbaut),
  • the polymeric component prior to any curing, have a viscosity at room temperature of at most 200,000 cps, preferably at most 100,000 cps, particularly at most 10,000 cps, especially at most 5,000 cps, more especially at most 1,000 cps.
  • This viscosity is generally measured by means of a Brookfield viscometer at the cure temperature, T c , if the polymeric component is curable, or at the mixing temperature at which the particulate fillers are dispersed and subsequently aligned if the polymeric component is not curable.
  • the term "magnetic” is used to include ferromagnetic, ferrimagnetic, and paramagnetic materials.
  • the filler may be completely magnetic, e.g. a nickel sphere, it may comprise a non-magnetic core with a magnetic coating, e.g. a nickel-coated ceramic particle, or it may comprise a magnetic core with a non-magnetic coating, e.g.
  • Suitable first fillers include nickel, iron, cobalt, ferric oxide, silver-coated nickel, silver-coated ferric oxide, or alloys of these materials. If the polymeric component is a gel, it is important that the selected filler not interfere with the crosslinking of the gel, i.e. not "poison" it.
  • the first filler is generally present in an amount of 0.1 to 30%, preferably 1 to 25%, particularly 2 to 20% by volume of the total composition.
  • the zinc borate and an oxidizing agent, e.g. magnesium perchlorate or potassium permanganate. It is preferred that the oxidizing agent be present in an amount 0.1 to 1.0 times that of the arc suppressing agent or flame retardant. Particularly good results are achieved when the oxidizing agent is coated onto the arc suppressing agent or flame retardant prior to mixing. While we do not wish to be bound by any theory, it is believed that the presence of the zinc borate and the oxidizing agent controls the plasma chemistry of the plasma generated during an electrical discharge, and provides discharge products that are nonconductive. The volume loading, shape, and size of the fillers affect the non-linear electrical properties and the breakdown voltage of the composition, in part because of the spacing between the particles. Any shape particle may be used, e.g.
  • first and second fillers are aligned columns per unit volume as possible to increase and/or maintain voltage breakdown stability, so a relatively small particle size filler for both the first and second fillers is preferred.
  • a mixture of different size, shape, and/or type particles may be used for the first, second, and third fillers.
  • first and second components are aligned in discrete regions in the polymeric component, e.g. as a column that extends through the polymeric component from one side to the other, or, when electrodes are present, as a column that extends through the polymeric component from the first electrode to the second electrode to form a resistive element.
  • Such domains can be formed in the presence of a magnetic field that causes the magnetic first and second filler particles to align.
  • a magnetic field that causes the magnetic first and second filler particles to align.
  • the polymeric component may be cured by any suitable means, including heat, light, microwave, electron beam, or gamma irradiation, and is often cured by using a combination of time and temperature suitable to substantially cure the resin.
  • the curing temperature T c may be at any temperature that allows substantial curing of the resin, i.e. that cures the resin to at least 70%, preferably at least 80%, particularly at least 90% of complete cure.
  • the curable polymeric component is a thermosetting resin which has a glass transition temperature Tg, it is preferred that the curing be conducted at a curing temperature T c which is greater than Tg.
  • a catalyst e.g. a platinum catalyst, may be added to initiate the cure and control the rate and/or uniformity of the cure.
  • Example 2 Following the procedure of Example 1, 5% by volume nickel (available from Alfa Aesar, with a mesh size of -250 mesh and a particle size of less than 53 to 63 microns), 5% by volume BaFe 1 O 19 , 10% by volume magnesium perchlorate (available from Alfa Aesar), 20% by volume zinc borate (available from Alfa Aesar), and 60% by volume silicone gel (formulated using 50% by weight 50 cs silicone oil, 50% by weight 10,000 cs divinyl-polydimethylsiloxane, and 0.2% by weight tetrakis(dimethyl siloxy silane)) were mixed.
  • nickel available from Alfa Aesar, with a mesh size of -250 mesh and a particle size of less than 53 to 63 microns
  • BaFe 1 O 19 10% by volume magnesium perchlorate (available from Alfa Aesar)
  • 20% by volume zinc borate available from Alfa Aesar
  • silicone gel formulated using 50% by weight 50 cs silicone oil, 50% by weight
  • Intermediate layers were formed from a conductive polymer composition prepared by drying blending 95% by volume ultrahigh molecular weight polyethylene having a molecular weight of about 4.0 million (Hostalen GUR-413, available from Hoechst) with 5% by volume carbon black (Ketjenblack EC 300, available from Akzo Chemie). The mixture was extruded through a ram extruder to produce a sintered rod and the rod was skived to produce a flexible tape 0.030 inch (0.76 mm) thick and 4.0 inch (102 mm) wide having a resistivity of about 2.5 ohm-cm. Two pieces of the tape were cut to the dimensions of the resistive element and were placed directly in contact with the element to sandwich it.
  • Figures 6a and 6b show the breakdown voltage for the Standard Impulse Breakdown Test at 60A and 250A, respectively, for 50 cycles. The device had substantially less scatter in breakdown voltage than devices shown in Figures 4 and 5.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Soft Magnetic Materials (AREA)

Abstract

L'invention concerne une composition électriquement non linéaire dans laquelle un constituant polymère durcissable (9) contient une première charge particulaire (13) magnétique et électroconductrice, une deuxième charge particulaire (15) magnétique et non électroconductrice, et éventuellement une troisième charge particulaire non électroconductrice et non magnétique. Les première et deuxième charges sont alignées dans des régions distinctes (11) du constituant polymère. Lorsque la composition est utilisée dans un dispositif électrique (1), ces régions distinctes s'étendent d'une première électrode (3) à une deuxième électrode (5).
PCT/US1996/009113 1995-06-07 1996-06-06 Composition electriquement non lineaire et dispositif WO1996041355A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US48102895A 1995-06-07 1995-06-07
US08/481,028 1995-06-07

Publications (1)

Publication Number Publication Date
WO1996041355A1 true WO1996041355A1 (fr) 1996-12-19

Family

ID=23910295

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1996/009113 WO1996041355A1 (fr) 1995-06-07 1996-06-06 Composition electriquement non lineaire et dispositif

Country Status (3)

Country Link
AR (1) AR002199A1 (fr)
TW (1) TW302486B (fr)
WO (1) WO1996041355A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999024992A1 (fr) * 1997-11-08 1999-05-20 Littelfuse, Inc. Composites polymeres destinees a la protection contre les surtensions
EP0930623A1 (fr) * 1998-01-16 1999-07-21 Littelfuse, Inc. Matériau polymère composite pour protection contre des décharges électrostatiques
WO2001047078A3 (fr) * 1999-12-23 2002-01-03 Mc Graw Edison Co Joint elastique forme entre des composants electriques
US7183891B2 (en) 2002-04-08 2007-02-27 Littelfuse, Inc. Direct application voltage variable material, devices employing same and methods of manufacturing such devices
US7202770B2 (en) 2002-04-08 2007-04-10 Littelfuse, Inc. Voltage variable material for direct application and devices employing same
US7258819B2 (en) 2001-10-11 2007-08-21 Littelfuse, Inc. Voltage variable substrate material
US8085520B2 (en) 2004-01-23 2011-12-27 Cooper Technologies Company Manufacturing process for surge arrester module using pre-impregnated composite
WO2017097976A1 (fr) * 2015-12-09 2017-06-15 Dbk David + Baader Gmbh Résistance de décharge

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4518737A (en) * 1978-12-26 1985-05-21 Rogers Corporation Dielectric material and method of making the dielectric material
WO1990005166A1 (fr) * 1988-11-09 1990-05-17 Raychem Limited Gels
US4977357A (en) * 1988-01-11 1990-12-11 Shrier Karen P Overvoltage protection device and material
US5294374A (en) * 1992-03-20 1994-03-15 Leviton Manufacturing Co., Inc. Electrical overstress materials and method of manufacture
US5322641A (en) * 1989-05-12 1994-06-21 Alcan International Limited Magnetic materials and products made therefrom

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4518737A (en) * 1978-12-26 1985-05-21 Rogers Corporation Dielectric material and method of making the dielectric material
US4977357A (en) * 1988-01-11 1990-12-11 Shrier Karen P Overvoltage protection device and material
WO1990005166A1 (fr) * 1988-11-09 1990-05-17 Raychem Limited Gels
US5322641A (en) * 1989-05-12 1994-06-21 Alcan International Limited Magnetic materials and products made therefrom
US5294374A (en) * 1992-03-20 1994-03-15 Leviton Manufacturing Co., Inc. Electrical overstress materials and method of manufacture

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999024992A1 (fr) * 1997-11-08 1999-05-20 Littelfuse, Inc. Composites polymeres destinees a la protection contre les surtensions
EP0930623A1 (fr) * 1998-01-16 1999-07-21 Littelfuse, Inc. Matériau polymère composite pour protection contre des décharges électrostatiques
WO2001047078A3 (fr) * 1999-12-23 2002-01-03 Mc Graw Edison Co Joint elastique forme entre des composants electriques
US6483685B1 (en) 1999-12-23 2002-11-19 Mcgraw Edison Company Compliant joint between electrical components
US7258819B2 (en) 2001-10-11 2007-08-21 Littelfuse, Inc. Voltage variable substrate material
US7183891B2 (en) 2002-04-08 2007-02-27 Littelfuse, Inc. Direct application voltage variable material, devices employing same and methods of manufacturing such devices
US7202770B2 (en) 2002-04-08 2007-04-10 Littelfuse, Inc. Voltage variable material for direct application and devices employing same
US7609141B2 (en) 2002-04-08 2009-10-27 Littelfuse, Inc. Flexible circuit having overvoltage protection
US8085520B2 (en) 2004-01-23 2011-12-27 Cooper Technologies Company Manufacturing process for surge arrester module using pre-impregnated composite
WO2017097976A1 (fr) * 2015-12-09 2017-06-15 Dbk David + Baader Gmbh Résistance de décharge

Also Published As

Publication number Publication date
TW302486B (fr) 1997-04-11
AR002199A1 (es) 1998-01-07

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