EP0235454A1 - Compositions contenant du noir de carbone et ayant une résistance à coefficient positif de température - Google Patents

Compositions contenant du noir de carbone et ayant une résistance à coefficient positif de température Download PDF

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Publication number
EP0235454A1
EP0235454A1 EP19860309505 EP86309505A EP0235454A1 EP 0235454 A1 EP0235454 A1 EP 0235454A1 EP 19860309505 EP19860309505 EP 19860309505 EP 86309505 A EP86309505 A EP 86309505A EP 0235454 A1 EP0235454 A1 EP 0235454A1
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EP
European Patent Office
Prior art keywords
carbon black
polymer
weight
amount
carbon
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.)
Withdrawn
Application number
EP19860309505
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German (de)
English (en)
Inventor
William M. Rowe, Jr.
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Sunbeam Corp
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Sunbeam Corp
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Filing date
Publication date
Application filed by Sunbeam Corp filed Critical Sunbeam Corp
Publication of EP0235454A1 publication Critical patent/EP0235454A1/fr
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/146—Conductive polymers, e.g. polyethylene, thermoplastics
    • 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

  • the present invention relates to a new semiconductive material which includes a suitable polymer or blend of polymers and a carbon black material.
  • This PTC phenomenon has been employed most effectively in the electric blanket industry to provide a grid of body heat-responsive PTC material surrounding a pair of conductive wires within a suitable blanket fabric material.
  • the PTC materials have been developed with sufficient self regulating precision to provide electrode (conductor) surrounding material having the capacity to sense and deliver heat to all parts of the body in proportion to the body heat requirements at any given time or location under the blanket without the necessity of internal blanket thermostats.
  • the PTC phenomenon is due to a loss or con­duction due to the more difficult electron tunneling through large intergrain gaps between conductive filler particles upon temperature rise. This theory is based upon the premise that the PTC phenomenon is due to a critical separation distance between carbon particles in the polymer matrix at the higher temperature. Still others have theorized that the PTC phenomenon is direct­ly related to the polymer crystallinity for a given polymer so that increased crystallinity in a particular polymer causes increased PTC anomaly. For this last theory, however, there is no correlation between de­grees of crystallization and the amount of PTC pheno­menon that might be experienced in different polymers.
  • Carbon blacks consist of spherical particles of elemental carbon permanently fused together during the manufacturing process to form aggregates. These aggregates are defined by particle size and surface area; aggregate size or structure (reticulate struc­ture); and surface chemistry.
  • the particle size of carbon blacks is the size of the individual particles which are fused together during manufacture to make the aggregate and varies inversely with the total surface area of the aggregates.
  • the surface area of carbon black aggregates is most commonly expressed in terms of nitrogen adsorption in m2/gram using the B.E.T. (Brunauer, Emmet, Teller) procedure well known in the art. Carbon blacks having a relatively small particle size, and therefore a relatively high aggre­gate surface area, exhibit better conductivity or lower volume resistivity.
  • the size and complexity of the carbon black aggregates is referred to as "structure” or "reticulate structure”.
  • Low structure carbon blacks consist of a relatively small number of spherical carbon particles fused together compactly during manufacture to provide a relatively small amount of void space within the aggregate.
  • High structure carbon blacks consist of more highly branched carbon particle chains which, when fused together during manufacture, provide a large amount of void space within the aggregate.
  • the structure level of carbon blacks is measured by its oil (dibutyl phthalate) absorption. Higher structure grades of carbon blacks absorb more oil than lower structure grades because of the larger void volume within the aggregates.
  • chemisorbed oxygen complexes such as carboxylic, quinonic, lactonic and phenolic groups on the aggregate surfaces.
  • Some carbon blacks are further surface treated to provide more chemisorbed oxygen on the aggregate surfaces.
  • These surface treated carbon blacks can be identified by their low pH, less than 4.0 and generally in the range of about 2.0 to 3.0, and/or by measuring the weight loss of dry carbon black when heated to 950° C. This weight loss is referred to as "volatile con­tent" and for surface treated carbon blacks, generally is at least 3.0 weight percent and generally in the range of about 5.0 to 10.0 weight percent.
  • carbon blacks impart some electrical conduc­tivity (or lessen volume resistivity) to normally non-conductive plastics depends upon four basic pro­perties of the carbon black: surface area, structure, porosity and surface treatment. Higher structure carbon blacks impart higher conductivity (lower volume resistivity) than lower structure grades because the long, irregularly-shaped aggregates provide a better electron path through the compound.
  • Surface treatment on the other hand, always causes the volume resisti­vity to be high (low conductivity) because the surface oxygen electrically insulates the aggregates.
  • PTC polymeric mater­ials One of the knowns about PTC polymeric mater­ials is that the polymer must, in its final state, be partly crystalline in order to exhibit PTC behavior.
  • Poly­meric matrix material having a sharp increase in re­sistance at a predetermined temperature (PTC material) to date has not been electrically conductive without an annealing period ranging from minutes to days.
  • U.S. Patent No. 3,861,029 points out that polymeric materials loaded with a sufficiently high percentage of carbon black to produce a conductive material when first prepared exhibit inferior flexibility, elonga­tion, crack resistance and undesirably low resistivity when brought to peak temperatures.
  • the present invention is directed to a revolutionary new semiconductive material having a sharp rise in electrical resistance at a predeter necessarilymined maximum temperature.
  • This revolutionary new material exhibits a sharp positive temperature coeffi­cient (PTC) of resistance at a predetermined tempera­ture with substantially reduced annealing times neces­sary after extrusion to achieve an essentially constant resistance at room temperature.
  • PTC positive temperature coeffi­cient
  • the PTC composition includes a suitable semicrystalline polymer; a suitable polymeric material including a sufficient number of polar molecules for electrical conductivity; and a finely divided, non surface-treated (essentially non-­oxidized surface as indicated by a pH of at least 4.0 and generally 5.0 to 8.5) carbon black having an inter­mediate dry volume resistivity with a critical relation­ship between N2 surface area and DBP absorption.
  • the carbon blacks incorporated into the compositions of the present invention are extremely mobile to permit rapid movement of the carbon particles during crystallization.
  • the mobility of the carbon blacks provides new and unexpectedly rapid crystallization after an extrusion or other material shaping process resulting in unexpectedly short thermal structuring (annealing) times.
  • the carbon blacks defined herein have been found to be capable of easily moving into the amorphous regions of the polymer por­tion of the composition of the present invention for the purpose of being disposed, quickly, sufficiently close to one or more polar moieties of the amorphous, polar material for interaction with the polar moieties to achieve excellent electrical conduction while exhibit­ing PTC behavior.
  • the carbon particles conduct electrons onto the polar moieties, e.g., carboxyl groups, of the amorphous polymer which then conduct electrons onto the crystal structure of the crystalline portion of the semicrystalline polymer resulting in electrical conductivity.
  • the mobility of the carbon blacks defined herein is extremely important in the crystallization process so that the carbon particles are capable of rapid movement away from the forming crystallites to permit the relatively unhindered, rapid formation of a regular crystal lattice structure through orderly chain packing, thereby substantially lessening the required annealing time.
  • an object of the present inven­tion is to provide a new and improved semiconductive composite polymer/conductive particle material wherein the conductive particles exhibit new and unexpected mobility to permit rapid crystallization of a semicrys­talline polymer to achieve a material having a constant resistance at room temperature with an unexpectedly short annealing period.
  • Another object of the present invention is to provide a new and improved semiconductive composite polymer material containing a crystalline or semi­crystalline polymer; a polymeric material containing polar molecules; and dispersed, finely divided conduc­tive carbon black particles requiring substantially shorter annealing after extrusion.
  • Still another object of the present invention is to provide a new and improved semiconducting compo­site polymeric material exhibiting a sharp positive temperature coefficient of resistance at a predeter­mined temperature.
  • Still another object of the present invention is to provide a new and improved polymeric composite material containing electrically conductive particles in an amount of 25% by weight or less while achieving a material having a stable conductivity and exhibiting sharp PTC behavior with very little annealing of the material needed after shaping.
  • a further object of the present invention is to provide a new and improved PTC material having non-surface treated low reticulate structure carbon blacks capable of substantial electrical conductivity with very little annealing needed.
  • the polymer component used in the semiconduc­tive materials of the present invention may be a single polymer or a mixture of two or more different polymers.
  • the polymers should have at least 10% crystallinity, and since greater crystallinity favors more intense PTC behavior, its crystallinity is preferable about 15% to 25% based on the polymer volume.
  • Suitable polymers include polyolefins, especially polymers of one or more ⁇ -olefins, e.g., polyethylene, polypropy­lene and ethylene, propylene copolymers. Excellent results have been obtained with polyethylene, preferivelyably low density polyethylene.
  • a material e.g., polymer, copolymer or terpolymer, providing a sufficient number of polar groups, e.g., carboxyl groups, is produced in an amount of about 5% by weight to about 20% by weight of the composition to provide sufficient conductivity to the composition.
  • the conductivity of the semiconductive materials of the present invention no longer increases at polar polymer loadings above about 20% by weight although more than 20% by weight of the polar polymer can be included so long as consistent with the structural (strength) requirements of the material.
  • Materials having more than one polar group e.g., di-carboxyls, provide the necessary conductivity to the materials at lower loadings, e.g., 2 to 3% by weight of the composition, while polymers having a single polar group such as ethylene ethyl acrylate, generally are required in an amount of at least about 5% by weight and preferably 10% to 20%.
  • Suitable examples of polar polymers include copolymers of one or more ⁇ -olefins, e.g., ethylene with one or more polar copolymers, e.g., vinyl acetate acrylic acid, ethyl acrylate and methyl acrylate such as ethylene vinyl acetate, ethy­lene ethyl acrylate, and its metal (e.g., Na, Zn) salts, ethylene acrylic acid, terpolymers of ethylene acrylic acid and/or its metal salts and methacrylic acid, polyethylene oxide and its metal salts and polyvinyl alcohol; polyarylenes, e.g., polyarylene ether ketones and sulfones and polyphenylene sulfide; polyesters, including polylactones, e.g., polybutylene terephtha­late, polyethylene terephthalate and polycaprolactone; polyamides; polycarbonates; and fluorocarbon polymers, i
  • the low structure, medium conductivity, low volatile content carbon blacks incorporated in the polymer matrix compositions of the present invention heretofore have not been used with the prior art poly­mers to obtain suitable PTC materials.
  • carbon blacks can be dispersed in the polymeric matrix mater­ials of the present invention, so long as one or more of the above-defined carbon blacks are present in an amount of 4 to 25% by weight and preferably 10 to 20% by weight of the polymeric matrix composition of the present invention.
  • suitable carbon blacks include Black Pearls 800, 880, 900 and 1100 and Regal 660 from Cabot Corp. and Raven 1250 and 1500 from Columbian Chemicals Company.
  • the above Cabot Corp. carbon blacks have apparent densities of 29, 23, 28, 24 and 31 pounds/ft3, respectively. Apparent density is informative of the physical condition of the carbon black - that is, whether the carbon black is in a fluffy or pelletized condition. Either fluffy or pelletized (beaded) forms of carbon black are useful in the present invention to achieve the new and unex­pected properties and advantages found in the composi­tions disclosed herein.
  • the semiconductive polymer matrix composi­tions containing dispersed carbon black particles forming the PTC materials of the present invention preferably contain an antioxidant in an amount of, for example, 0.5 to 4% based on the volume of the polymeric material, as well known in the art, for example, a 1,3-di-t-butyl-2-hydroxy phenyl antioxidant.
  • the antioxidant prevents degradation of the polymer during processing and during ageing.
  • the matrix also can include conventional components such as non-conduc­tive fillers, processing aids, pigments and fire retard­ants.
  • the matrix is preferable shaped by melt-extru­sion, molding or other melt-shaping operation. Exces­sive working of the polymer matrix composition should be avoided to prevent excessive resistivity in the material.
  • the carbon black and any other components are incorporated into polymeric materials using a high-shear intensive mixer such as a Banbury Mixer.
  • a high-shear intensive mixer such as a Banbury Mixer.
  • the material from the Banbury Mixer can be pelletized by feeding it into a chopper and collecting the chopped material and feeding it to a pelletized extruder.
  • the pelletized mix can be used for subse­quent casting of the mix of for extrusion onto appro­priate electrodes to produce heating wire, sensing devices, and the like, and thereafter the product is provided, if desired, with the extrusion of a suitable shape retaining and/or insulating jacket followed by relatively short thermal structuring (annealing).
  • the polymeric matrix composition After the polymeric matrix composition has been shaped, it is then cross-linked to immobilize the conductive carbon black particles dispersed throughout the polymeric material.
  • the cross-linking traps the conductive particles to prevent them from migrating, although there is some mobility in migration of the carbon particles during crystallization when it is believed that the conductive particles are swept into the amorphous regions of the semicrystalline polymeric material.
  • Cross linking not only immobilizes the carbon particles, but also cross-links the amorphous polymer molecules thereby immobilizing the crystalline portion of the polymer and the carbon black in proper position for electron tunneling.
  • the polymeric matrix preferably is cross-linked by irradia­tion. The cross-linking forms strong carbon-carbon bonds to effectively immobilize the free carbon parti­cles in their positions at the time of cross-linking to prevent the formation of conductive carbon chains above the melt transition temperature.
  • the polymeric matrix material should be irradiated to a total dose that exceeds 20 Mrads. pre­ ferably at least 30 Mrad.
  • the carbon black while necessary in order to produce a polymeric matrix having a sharp increase in resistance at a predetermined temperature requiring a relatively short anneal time appears to be a relatively minor although necessary conduction material in the PTC materials of the present invention.
  • composition of the present invention containing possibly less carbon black load­ing than the materials of the prior art, have excellent properties of elongation, flexibility and crack resis­tance. Further, because the tunneling mode of electri­cal conductivity is the major mode of electrical con­duction in the materials of the present invention, although the carbon black loading is relatively small, the material has good initial conductivity shortly after exiting the extruder while also achieving very high resistance at the higher temperatures as necessary in accordance with the PTC phenomenon.
  • the polymeric matrix materials of the present invention are particularly useful for the manufacture of self limiting heating wire, for electric blankets and the like.
  • a suitable electric blanket generally designated by numeral 10, containing heating wire, generally designated 12, manufactured with the polymeric matrix compositions of the present invention.
  • the heating wire 12 contains a pair of spaced conductors 14 and 16 which may be suitably wrapped around core materials 18 and 20, respectively, as well known in the art.
  • this heating cable 12 is disposed within a suitable fabric material, e.g. polyester and/or acrylic fabric 28 provided with an electrically connected on-­off switch 30 and an ambient responsive control 32.
  • Such heating wires exhibiting PTC character­istics are well known and have extruded thereon (in accordance with standard extrusion techniques) the composition of this invention generally designated by reference numeral 22 in what is referred to as a "dumb­bell" cross-section so as to cover the conductors 14, 16 and cores 18 and 20 and provide a continuous inter-­connecting web 24 of polymeric matrix material forming heating paths, as shown in FIG. 1.
  • a suitable form-­retaining and insulating jacket or covering 26 is also extruded by conventional techniques over the full length of the heating cable 12.
  • Cross-linking is effected preferably by irradiation immediately after extrusion.
  • the desired annealing for the requi­site time is thereafter provided at the desired tempera­ture, the cable being conventionally spooled for ease of handling and placed in a suitable oven.
  • this heating cable 12 is disposed within a suitable fabric material, e.g., polyester and/or acrylic fabric 28 provided with an electrically connected on-off switch 30 and an ambient responsive control 32.
  • a suitable fabric material e.g., polyester and/or acrylic fabric 28 provided with an electrically connected on-off switch 30 and an ambient responsive control 32.
  • the polymeric matrix material forming the ground wire or other con­figuration becomes relatively insensitive to temperatures in the melting range of most jacketing materials. Accordingly, if the jacket is extruded around the polymeric matrix material at 2 to 3 hundred feet per minute, there will be no problems with heat degrada­tion. However, if the extrusion process is stopped for any reason, the polymeric matrix material in the extruder cross head may undergo degradation.
  • Composite polymeric matrix materials were prepared using only 14.4% Regal 660 carbon black from Cabot Corporation having a nitrogen surface area of 112 m2/gram, a particle size of 24 millimicrons, a DBP of 60cc/100grams, a volatile content of 1.0%, a pH of 7.5, and an apparent density of 31 pounds/ft3.
  • the polymer used was a combination of Union Carbide DFD 6005 polyethylene and an ethylene ethyl acrylate copolymer. The formulation was as follows:
  • the materials of the above formulation were granulated, mixed in a Banbury mixer, and plaques were pressed from the ground materials around a pair of electrodes at a temperature of 350°F at 1500 p.s.i.g. for three minutes and the volume resistivity measured and found to be 6,154 ohm-cm.
  • the material of the above formulation was then extruded around a pair of electrodes, as shown in the drawing, and it was found that constant room temperature conductivity was achieved within 70 seconds of annealing at 350°F.
  • the resulting PTC wire had a room temperature conduc­tivity of 2.4 watts per foot and excellent steeply sloped PTC behavior.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermistors And Varistors (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
EP19860309505 1985-12-06 1986-12-05 Compositions contenant du noir de carbone et ayant une résistance à coefficient positif de température Withdrawn EP0235454A1 (fr)

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US80588085A 1985-12-06 1985-12-06
US805880 1985-12-06

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EP0235454A1 true EP0235454A1 (fr) 1987-09-09

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EP (1) EP0235454A1 (fr)
JP (1) JPS62155502A (fr)
AU (1) AU589714B2 (fr)
NZ (1) NZ218551A (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0307205A2 (fr) * 1987-09-09 1989-03-15 Raychem Limited Composition de polymère conductible
WO1989012308A1 (fr) * 1988-06-03 1989-12-14 Raychem Corporation Composition ctp polymere et son dispositif electrique
WO1990003651A1 (fr) * 1988-09-20 1990-04-05 Raychem Corporation Composition polymere conductrice
WO1990003420A1 (fr) * 1988-09-20 1990-04-05 Raychem Corporation Composition polymere conductrice
US4980541A (en) * 1988-09-20 1990-12-25 Raychem Corporation Conductive polymer composition
US5181006A (en) * 1988-09-20 1993-01-19 Raychem Corporation Method of making an electrical device comprising a conductive polymer composition
WO1993023968A1 (fr) * 1992-05-19 1993-11-25 Gustavsson Magnus Peter M Dispositif de rechauffement electrique
WO1998001010A1 (fr) * 1996-06-28 1998-01-08 Raychem Corporation Cable de chauffage
EP0908902A2 (fr) * 1997-10-07 1999-04-14 Sony Chemicals Corporation Elément PTC, dispositif de protection et panneau à circuit électrique
EP3440140A4 (fr) * 2016-04-08 2020-07-22 Littelfuse, Inc. Feuille ultramince à coefficient de température positif et son procédé de fabrication
US10834786B2 (en) 2016-01-12 2020-11-10 3M Innovative Properties Company Heating tape and system
CN114085518A (zh) * 2021-10-27 2022-02-25 金发科技股份有限公司 一种阻燃尼龙复合材料及其制备方法和应用

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4818439A (en) * 1986-01-30 1989-04-04 Sunbeam Corporation PTC compositions containing low molecular weight polymer molecules for reduced annealing

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4388607A (en) * 1976-12-16 1983-06-14 Raychem Corporation Conductive polymer compositions, and to devices comprising such compositions
JPS6093702A (ja) * 1983-10-26 1985-05-25 松下電器産業株式会社 導電性組成物の製造方法

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU583655B2 (en) * 1985-09-02 1989-05-04 Commonwealth Scientific And Industrial Research Organisation Method for producing composite metal articles

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4388607A (en) * 1976-12-16 1983-06-14 Raychem Corporation Conductive polymer compositions, and to devices comprising such compositions
JPS6093702A (ja) * 1983-10-26 1985-05-25 松下電器産業株式会社 導電性組成物の製造方法

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0307205A2 (fr) * 1987-09-09 1989-03-15 Raychem Limited Composition de polymère conductible
EP0307205A3 (fr) * 1987-09-09 1991-03-20 Raychem Limited Composition de polymère conductible
WO1989012308A1 (fr) * 1988-06-03 1989-12-14 Raychem Corporation Composition ctp polymere et son dispositif electrique
US5250226A (en) * 1988-06-03 1993-10-05 Raychem Corporation Electrical devices comprising conductive polymers
WO1990003651A1 (fr) * 1988-09-20 1990-04-05 Raychem Corporation Composition polymere conductrice
WO1990003420A1 (fr) * 1988-09-20 1990-04-05 Raychem Corporation Composition polymere conductrice
US4980541A (en) * 1988-09-20 1990-12-25 Raychem Corporation Conductive polymer composition
US5093036A (en) * 1988-09-20 1992-03-03 Raychem Corporation Conductive polymer composition
US5181006A (en) * 1988-09-20 1993-01-19 Raychem Corporation Method of making an electrical device comprising a conductive polymer composition
EP0803879A1 (fr) * 1988-09-20 1997-10-29 Raychem Corporation Composition polymère conductrice
US5643480A (en) * 1992-05-19 1997-07-01 Nordica S.P.A. Field of the invention
WO1993023968A1 (fr) * 1992-05-19 1993-11-25 Gustavsson Magnus Peter M Dispositif de rechauffement electrique
WO1998001010A1 (fr) * 1996-06-28 1998-01-08 Raychem Corporation Cable de chauffage
US6005232A (en) * 1996-06-28 1999-12-21 Raychem Corporation Heating cable
EP0908902A2 (fr) * 1997-10-07 1999-04-14 Sony Chemicals Corporation Elément PTC, dispositif de protection et panneau à circuit électrique
EP0908902A3 (fr) * 1997-10-07 1999-09-22 Sony Chemicals Corporation Elément PTC, dispositif de protection et panneau à circuit électrique
US6114672A (en) * 1997-10-07 2000-09-05 Sony Corporation PTC-element, protective device and electric circuit board
US10834786B2 (en) 2016-01-12 2020-11-10 3M Innovative Properties Company Heating tape and system
EP3440140A4 (fr) * 2016-04-08 2020-07-22 Littelfuse, Inc. Feuille ultramince à coefficient de température positif et son procédé de fabrication
CN114085518A (zh) * 2021-10-27 2022-02-25 金发科技股份有限公司 一种阻燃尼龙复合材料及其制备方法和应用

Also Published As

Publication number Publication date
AU589714B2 (en) 1989-10-19
NZ218551A (en) 1989-11-28
JPS62155502A (ja) 1987-07-10
AU6588486A (en) 1987-06-11

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