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WO2025125647A1 - Dispositif de chauffage autorégulé - Google Patents

Dispositif de chauffage autorégulé Download PDF

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Publication number
WO2025125647A1
WO2025125647A1 PCT/EP2024/086391 EP2024086391W WO2025125647A1 WO 2025125647 A1 WO2025125647 A1 WO 2025125647A1 EP 2024086391 W EP2024086391 W EP 2024086391W WO 2025125647 A1 WO2025125647 A1 WO 2025125647A1
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WO
WIPO (PCT)
Prior art keywords
semiconductive
portions
layer
electrically
composition
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.)
Pending
Application number
PCT/EP2024/086391
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English (en)
Inventor
Per-Ola Hagstrand
Niklas THORN
Sven EDEBLAD
Florian Schütz
Suhas Donthy SURESH BABU
Juan Pablo TORRES
Mithun GOSWAMI
Bert Broeders
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.)
Borealis GmbH
Original Assignee
Borealis GmbH
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Filing date
Publication date
Application filed by Borealis GmbH filed Critical Borealis GmbH
Publication of WO2025125647A1 publication Critical patent/WO2025125647A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • 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
    • 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
    • H05B3/02—Details
    • H05B3/03—Electrodes
    • 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
    • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
    • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
    • 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
    • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
    • H05B3/34—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater flexible, e.g. heating nets or webs
    • 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
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/011—Heaters using laterally extending conductive material as connecting means
    • 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
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/013—Heaters using resistive films or coatings
    • 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
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/017—Manufacturing methods or apparatus for heaters
    • 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
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/02—Heaters using heating elements having a positive temperature coefficient
    • 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
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/029—Heaters specially adapted for seat warmers
    • 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
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/036—Heaters specially adapted for garment heating

Definitions

  • This invention relates to a self-regulating heater and to processes for the preparation of such a structure.
  • the invention relates to an electrical heater comprising a semiconductive layer of an electrically semiconductive composition with a positive temperature coefficient where a plurality of semiconductive portions are located on and protrude from the electrically semiconductive layer. These semiconductor portions act as the conductors within the heater transferring power from a power source to the semiconductive layer.
  • Parallel resistance self-regulating heating cables are known. Such cables normally comprise two conductors extending longitudinally along the cable. Typically, the conductors are embedded within a resistive polymeric heating element, the element being extruded continuously along the length of the conductors.
  • the cable thus has a parallel resistance form, with power being applied via the two conductors to the heating element connected in parallel across the two conductors.
  • the heating element usually has a positive temperature coefficient of resistance. Thus as the temperature of the heating element increases, the resistance of the material electrically connected between the conductors increases, thereby reducing power output.
  • Such heating cables, in which the power output varies according to temperature are said to be self-regulating or self-limiting.
  • Self-regulation utilises a conversion from electrical to thermal energy by allowing a current to pass through a semiconductive medium with Positive temperature coefficient (PTC) characteristics, which elevates the object temperature above that of its surroundings, until a steady state is reached (self-regulation).
  • PTC Positive temperature coefficient
  • a material with a PTC has an electrical resistance that increases with temperature, and is the mechanism behind the self-regulating function.
  • PTC cables are often used in underfloor heating or wrapped around pipes for e.g. anti-freeze purposes. Cables however, do not offer a significant surface area of heat so it takes a large number of cables to provide underfloor heating for example.
  • an electrical heater that comprises conductors and a heating element disposed between the conductors wherein the heating element comprises an electrically conductive material distributed within a first electrically insulating material.
  • the insulating material separates the conductor from the electrically conductive material.
  • US7250586 describes a surface heating system for a car seat or the like comprising a support and a heating layer that contains an electrically conductive plastic, which is characterized by the fact that the heating layer is formed by a flexible film and that the support is flexible.
  • US4247756 describes a heated floor mat in which two inner electrically conductive inner layers sandwich conductors. These conductors are adhered to the inner layers.
  • US7053344 describes a flexible heater for a fabric.
  • US2021112631 describes a heating element that has at least one film of an electrically conductive polymer material.
  • US5451747 discloses a heat mat with PTC material.
  • WO2008/133562 describes a heating device comprising two elongated electrodes arranged at a distance and being inter-connected by a semiconducting heat generating member of a polymer based material having positive temperature coefficient regarding resistivity (PTC-material), wherein the heat generating member comprises electrode interconnection sections of a low resistivity PTC material compared with the PTC material of intermediate section.
  • PTC-material positive temperature coefficient regarding resistivity
  • EP1275274 describes a device for floor heating comprising a bendable, electrically conductive, thermoplastic mat.
  • the device is provided with at least two electrodes. Current is conducted through the device, which heats up and emits heat.
  • WO2021/188595 describes a blanket comprising a first outer panel, a selfregulating heating element proximate to said first outer panel and a second outer panel proximate to said self-regulating heating element joined to said first outer panel wherein said first outer panel and said second outer panel contain said selfregulating heating elements.
  • WO2022/129251 describes a self-regulating flat sheet heater prepared by coextrusion where conductors are embedded within the semiconductive composition.
  • EP-A-100919 discloses a sheet-shaped heater comprising plural electrode covering members, each electrode covering member covering a wire like electrode. This arrangement of electrode and covering member is located on a sheet-shaped heating resistance sheet. This sheet can be a PTC sheet.
  • the relatively low conductivity of the semiconductive portions compared to metal conductors is compensated by increased cross-sectional area.
  • the polymer used in all the semiconductive materials present in the heater can be the same and hence the heater can be prepared as a mono-material construction, facilitating easy recycling.
  • an electrical heater such as a flat sheet electrical heater, comprising a semiconductive layer, said semiconductive layer comprising a first electrically semiconductive composition with a positive temperature coefficient, said first semiconductive composition comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; a plurality of semi-conductive portions located on and protruding from the semiconductive layer wherein said semiconductive portions comprise a second electrically semiconductive composition with a positive temperature coefficient said second electrically semiconductive composition comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; wherein the semi-conductive portions are arranged on the semiconductive layer in a regular pattern; and wherein said semi-conductive portions have a conductance which is higher, such as at least 5x higher, than the semiconductive layer, e.g. wherein the higher conductance of said semi-conductive portions being provided through geometry, spacing, thickness and/or content of conductive filler of the semiconductive portions.
  • each semi-conductive portion which are preferably the same, is 0.05 to 0.5 times the distance between adjacent semiconductive portions.
  • the distance between adjacent semi- conductive portions is measured as the distance between the nearest edges of two adjacent semiconductive portions.
  • an electric heater such as a flat sheet electrical heater, comprising a semiconductive layer, said semiconductive layer comprising a first electrically semiconductive composition with a positive temperature coefficient, said first semiconductive composition comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; a plurality of semi-conductive portions located on and protruding from the electrically semiconductive layer wherein said semiconductive portions comprise a second electrically semiconductive composition with a positive temperature coefficient said second semiconductive composition comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; wherein the semi-conductive portions are arranged on the semiconductive layer in a regular pattern; and said semi-conductive portions are at least two times thicker than the semiconductive layer. It is preferred if the width of each semi-conductive conductor portion, which are preferably the same, is 0.05 to 0.5 times the distance between adjacent semi- conductive portions.
  • the invention provides the use of a second semiconductive composition with a positive temperature coefficient comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler as a conductor in a heating device comprising a first electrically semiconductive composition, which may be the same or different to the second composition, having a positive temperature coefficient and comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler.
  • the present invention relates to an electrical heater in which conventional metal conductors such as metal wires are replaced with semiconductive portions which are located on and protrude from the semiconductive layer in the heater.
  • the resulting structure can be made almost exclusively from recyclable polymer material.
  • the heater provides heat in a safe, cheap and simple manner.
  • the heater of the invention uses the principle of positive temperature coefficient (PTC). To avoid overheating and potential destruction of the heater, the heat generated is self-limiting and requires no regulating electronics. As temperature increases within the semiconductive layer caused by the power applied to the semiconductive portions, resistance within the semiconductive layer increases until a steady state is reached and no further heating takes place. In one embodiment therefore, the heater of the invention contains no regulating electronics, e.g. a heat cut off to prevent overheating.
  • PTC positive temperature coefficient
  • the first and second electrically semiconductive compositions cannot overheat and require no overheat protection.
  • the technical solution in this particular invention utilises conversion from electrical to thermal energy by allowing a current to pass through a semiconductive composition with PTC characteristics, which elevates the object temperature above that of its surroundings, until a steady state is reached (self-regulation).
  • the first and second electrically semiconductive compositions preferably comprise a polyethylene and a conductive filler (e.g. carbon black). They can be the same or different.
  • the self-regulating thermal phenomenon occurs due to two parallel antagonistic processes: a. Poor conduction of electrons through the semiconductive medium generates electrical losses, manifested in heat emission. b. Thermal expansion of the non-conductive part of the material leads to further decrease of the conductivity by separation of the conductive filler particles.
  • the temperature increase in the first electrically semiconductive layer is governed by a number of factors. These include the distance between the semiconductive portions present, the conductance of the semiconductive portions, the dimensions of the semiconductive portions, the thickness of the electrically semiconductive layer, the amount of conductive filler present in the first electrically semiconductive composition, and the applied voltage.
  • a thicker electrically semiconductive layer increases the temperature at which a steady elevated temperature plateau is reached.
  • the steady state elevated temperature in the semiconductive layer is no more than 50°C, such as no more than 45°C.
  • the heater should ideally achieve a temperature of at least 30 °C.
  • the heater of the invention comprises a first electrically semiconductive composition which forms a semiconductive layer structure within the heater.
  • the first semiconductive layer therefore comprises or consists of the first electrically semiconductive composition.
  • the first electrically semiconductive composition comprises a polyethylene.
  • the heater of the invention is essentially a flexible flat sheet which can be manipulated into desired shapes (such as a cylinder) as required.
  • the heater therefore comprises a first electrically semiconductive composition in a semiconductive layer.
  • This first electrically semiconductive composition comprises a polyethylene, a polypropylene or a mixture thereof. It is preferred if the first semiconductive composition comprises a polyethylene. It preferred if the polyethylene is one prepared in a high temperature autoclave or tubular process such as a LDPE homopolymer or copolymer.
  • LDPE low density polyethylene
  • HP polyethylene low density polyethylene
  • LDPE-like high pressure (HP) polyethylenes The term LDPE describes and distinguishes only the nature of HP polyethylene with typical features, such as different branching architecture, compared to the polyethylene produced in the presence of an olefin polymerisation catalyst.
  • LDPE means a low density homopolymer of ethylene (referred herein as LDPE homopolymer) or a low density copolymer of ethylene with one or more comonomer(s) (referred herein as LDPE copolymer).
  • the first electrically semiconductive composition comprises an LDPE copolymer.
  • the one or more comonomers of LDPE copolymer are preferably selected from the polar comonomer(s), non-polar comonomer(s) or from a mixture of the polar comonomer(s) and non-polar comonomer(s).
  • said LDPE homopolymer or LDPE copolymer may optionally be unsaturated.
  • polar comonomer(s) containing carboxyl and/or ester group(s) are used as said polar comonomer.
  • the polar comonomer(s) of LDPE copolymer is selected from the groups of acrylate(s), methacryl ate(s) or acetate(s), or any mixtures thereof.
  • the polar comonomer(s) is preferably selected from the group of alkyl acrylates, alkyl methacrylates or vinyl acetate, or a mixture thereof.
  • the use of ethylene alkyl acylates or ethylene vinyl acetate is preferred.
  • said polar comonomers are selected from Ci- to Ce-alkyl acrylates, Ci- to Ce-alkyl methacrylates or vinyl acetate.
  • said LDPE copolymer is a copolymer of ethylene with Ci- to C4-alkyl acrylate, such as methyl, ethyl, propyl or butyl acrylate, or vinyl acetate, or any mixture thereof.
  • EMA ethylene methyl acrylate
  • ESA ethylene ethyl acrylate
  • EBA ethylene butyl acrylate
  • EVA ethylene vinyl acetate
  • non-polar comonomer(s) for the LDPE copolymer preferred options are polyunsaturated comonomers comprising C and H atoms only.
  • the polyunsaturated comonomer consists of a straight carbon chain with at least 8 carbon atoms and at least 4 carbon atoms between the non-conjugated double bonds, of which at least one is terminal.
  • a preferred diene compound is 1,7-octadiene, 1,9-decadiene, 1,11- dodecadiene, 1,13 -tetradecadiene, or mixtures thereof. Furthermore, dienes like 7- methyl-l,6-octadiene, 9-methyl-l,8-decadiene, or mixtures thereof can be mentioned.
  • the LDPE polymer is a copolymer, it preferably comprises 1.0 to 40 wt.- %, more preferably 5.0 to 35 wt.-%, still more preferably 10 to 30 wt%%, of one or more comonomer(s).
  • the comonomer content is preferably 5.0 to 30 wt%, such as 7.5 to 20 wt% in the polymer.
  • EMA ethylene methyl acrylate
  • ESA ethylene ethyl acrylate
  • EBA ethylene butyl acrylate
  • EVA ethylene vinyl acetate
  • the MFR of the polymer when measured under a load of 21.6 kg/125°C may be 4.0 g/lOmin or more are required, such as at least 6.0 g/10 min, even more preferably 8.0 to 15 g/10 min, and most preferably at least 10.0 g/10 min.
  • An upper limit of 25 g/1 Omin is preferred, such as 18 g/1 Omin.
  • Any LDPE homopolymer or copolymer may have a density of 905 to 935 kg/m 3 , such as 910 to 925 kg/m 3 .
  • the polyethylene can be produced by any conventional polymerisation process.
  • it is an LDPE and is produced by radical polymerisation, such as high pressure radical polymerisation.
  • High pressure polymerisation can be effected in a tubular reactor or an autoclave reactor.
  • it is a tubular reactor.
  • the pressure can be within the range of 1200-3500 bars and the temperature can be within the range of 150°C-350°C. Further details about high pressure radical polymerisation are given in WO93/08222, which is herewith incorporated by reference.
  • the first electrically semiconductive composition may comprise at least 50 wt% of the polyethylene, polypropylene or mixture thereof, such as at least 60 wt%. Any layer in which the first electrically semiconductive composition is present may consist of the first electrically semiconductive composition. Thus, any layer in which the first electrically semiconductive composition is present may comprise at least 50 wt% of the polyethylene, polypropylene or mixture thereof, such as at least 60 wt%. The polyethylene, polypropylene or mixture thereof will form the balance of the first electrically semiconductive composition once all other components are determined.
  • the first electrically semiconductive composition further comprises a conductive filler such as carbon black.
  • a conductive filler such as carbon black.
  • Suitable conductive fillers include graphite, graphene, carbon fibres, carbon nanotubes, metal powders, metal strands or carbon black. The use of carbon black is preferred.
  • the amount of conductive filler is at least such that a semiconducting composition is obtained.
  • the amount of conductive filler can vary.
  • the first electrically semiconductive composition comprises 5-50 wt% conductive filler, such as 15 to 50 wt%.
  • the amount of conductive filler is 5-48 wt.-%, 10-45 wt%, 20-45 wt%, 25-45 wt% or 30-41 wt%, based on the weight of the first electrically semiconductive composition.
  • the first composition may comprise 5-50 wt% conductive filler, such as 15 to 50 wt%.
  • the amount of conductive filler in the first layer is 5-48 wt.%, 10-45 wt%, 20-45 wt%, 25-45 wt% or 30-41 wt%, based on the weight of the layer.
  • Any carbon black can be used which is electrically conductive.
  • suitable carbon blacks include furnace blacks, channel blacks, gas blacks, lamp blacks, thermal blacks and acetylene blacks. Additionally, graphitised furnace blacks (as produced by Imerys) and high structure blacks (known as Ketjenblacks produced by Nouryon) may also be used. Mixtures may also be used. Where a blend of carbon blacks is used then this percentage refers to the sum of the carbon blacks present.
  • the carbon black may have a nitrogen surface area (BET) of 5 to 1500 m 2 /g, for example of 10 to 300 m 2 /g, e.g. of 30 to 200 m 2 /g, when determined according to ASTM D3037-93. Further, the carbon black may have one or more of the following properties: i) a primary particle size of at least 5 nm which is defined as the number average particle diameter according to ASTM D3849-95a, ii) iodine adsorption number (IAN) of at least lOmg/g, for example 10 to 300 mg/g, e.g.
  • BET nitrogen surface area
  • DBP dibutyl phthalate
  • absorption number oil absorption number
  • the carbon black may have one or more of the following properties: a) a primary particle size of at least 15 nm which is defined as the number average particle diameter according ASTM D3849-95a; b) iodine number of at least 30 mg/g according to ASTM DI 510; c) oil absorption number of at least 30 ml/lOOg which is measured according to ASTM D2414.
  • Furnace carbon blacks are preferred. This is a generally acknowledged term for the well-known carbon black type that is produced continuously in a furnacetype reactor.
  • carbon blacks the preparation process thereof and the reactors, reference can be made to i.a. EP-A-0629222 of Cabot, US 4,391,789, US 3,922,335 and US 3,401,020.
  • ASTM D 1765-98b i.a. N351, N293 and N550, can be mentioned.
  • the first semiconductive composition may be crosslinked using peroxide or silane moisture curing systems. Crosslinking may also be effected using irradiation to avoid the need for a crosslinking agent.
  • the semiconductive composition of the invention is preferably not crosslinked.
  • the first semiconductive composition may contain an antioxidant.
  • an antioxidant sterically hindered or semi-hindered phenols, aromatic amines, aliphatic sterically hindered amines, organic phosphates, thio compounds, polymerized 2,2,4- trimethyl-l,2-dihydroquinoline and mixtures thereof, can be mentioned.
  • the antioxidant is selected from the group of 4,4'- bis(l,l'dimethylbenzyl)diphenylamine, para-oriented styrenated diphenylamines, 4,4’-thiobis (2 -tert, butyl-5-methylphenol), polymerized 2,2,4-trimethyl-l,2- dihy droquinoline, 4-( 1 -methyl- 1 -phenylethyl)N- [4-( 1 -methyl- 1 -phenyl ethyl )phenyl] aniline or derivatives thereof.
  • the antioxidant is selected from the group (but not limited to) of 4,4'- bis(l,l'dimethylbenzyl)diphenylamine, para-oriented styrenated diphenylamines, 4,4’-thiobis (2-tert. butyl-5-methylphenol), 2,2’-thiobis(6-t-butyl-4- methylphenol), distearylthiodipropionate, 2,2’-thio-diethyl-bis-(3-(3,5-di-tertbutyl- 4-hydroxyphenyl)propionate, polymerized 2, 2, 4-trimethyl-l,2-dihy droquinoline, or derivatives thereof.
  • the antioxidants may be used but also any mixture thereof.
  • the amount of antioxidant can range from 0.005 to 2.5 wt-%, such as 0.01 to 2.5 wt-%, preferably 0.01 to 2.0 wt-%, more preferably 0.03 to 2.0 wt-%, especially 0.03 to 1.5 wt-%, more especially 0.05 to 1.5 wt%, or 0.1 to 1.5 wt% based on the weight of the semi conductive composition.
  • the first semiconductive composition may comprise further additives.
  • additives stabilisers, processing aids, flame retardant additives, acid scavengers, inorganic fillers, voltage stabilizers, or mixtures thereof can be mentioned.
  • the first electrically semiconductive composition has a volume resistivity, measured at 40°C, of less than 20 Ohm • cm
  • the first electrically semiconductive composition has a volume resistivity, measured at 25°C, of less than 12 Ohm • cm
  • the semiconductive layer may have a thickness of 50 to 3000 pm, such as 75 to 2000 pm, especially 100 to 1000 pm. It is especially preferred if the thickness is 125 to 800 pm.
  • the heater of the invention may take the form of a sheet, such as a flat sheet, and therefore contain a number of layers.
  • a semiconductive layer comprising the first electrically semiconductive composition
  • a further layer may be present which acts as an insulation layer.
  • a decorative top layer may also be present.
  • the electrical heater is provided with at least one further layer above and/or at least one further layer below said electrically semiconductive layer, preferably an insulation layer, e.g. a thermal insulation layer.
  • the semiconductive layer is provided with semiconductive portions thereon. It is particularly preferred if the gap between the semiconductive portions is filled with an insulating polymer layer such as a layer based on a polyethylene as herein defined but in the absence of the conductive filler.
  • an LDPE copolymer comprising a polyunsaturated comonomer consisting of a straight carbon chain with at least 8 carbon atoms and at least 4 carbon atoms between the non- conjugated double bonds, of which at least one is terminal.
  • the gap between the semiconductive portions is filled with a second layer of the semiconductive composition as defined herein, i.e. one with a lower conductance that the semiconductive portions.
  • the semiconductive composition used to prepare this second layer is conveniently the same as that used to prepare the semiconductive layer.
  • the heater of the invention may be provided with one or more layers to protect the semiconductive composition from damage.
  • an aesthetic top layer can be textile fabric, non-woven or solid sheet (rubber, plastic, paper, wood, metal, etc.).
  • no top layer(s) are used.
  • Any additional layer may be extrudable, e.g. a polyolefin layer.
  • the heater is provided with an insulation layer or heat reflective layer at the base of the heater.
  • Such an insulation layer may be electrically insulating, thermally insulating or both.
  • Such a layer increases the heating effectiveness of the heater.
  • Such a layer may comprise a polyolefin such as a polyethylene, especially an LDPE, e.g. an LDPE homopolymer or copolymer.
  • Preferred insulation layers use LDPE as the only polymer component.
  • Such a layer is preferably one that can be coextruded although lamination of this layer is also an option.
  • the heater may be provided with a support to provide mechanical strength.
  • a conventional PTC heater there are a plurality of metal conductors, typically wires.
  • these metallic conductors are replaced a plurality of electrically semiconductive portions which are located on and protrude from the electrically semiconductive layer. These portions have a higher conductance that the first electrically semiconductive composition/layer, e.g. because of their geometric shape or due to increases in the amount of conductive filler present relative to the filler content in the semiconductive layer.
  • the skilled person can devise various means of increasing the conductance of the semiconductive portions.
  • the semi-conductive portions have a conductance which is higher, such as at least 5x higher than the electrically semiconductive composition/layer. In one embodiment, the semi-conductive portions have a conductance which is higher, such as 2 to 20 x higher than the electrically semiconductive composition/layer. Conductance is measured as 1/resistance and is measured from the ratio between applied voltage and resulting current (Ohm’s law).
  • the term plurality is used herein to imply at least 2, preferably at least 4 semiconductive portions.
  • the heater of the invention comprises an even number of semiconductive portions.
  • the semiconductive portions have alternate polarity.
  • the semiconductive portions comprise a second electrically semiconductive composition which comprises a polyethylene, polypropylene or a mixture thereof and a conductive filler.
  • the first and second electrically semiconductive compositions can be the same or different.
  • the semiconductive portions may consist of a second electrically semiconductive composition.
  • the second electrically semiconductive composition preferably comprises a polyethylene.
  • the second electrically semiconductive composition preferably consists essentially of a polyethylene and a conductive filler, i.e. these are the only components present other than any standard polymer additives.
  • the semiconductive portions preferably consist of the second electrically semiconductive composition so it is preferred if the semiconductive portions consist of polyethylene and conductive filler only.
  • the nature of the polyethylene and the conductive filler are as defined above for the first electrically semiconductive composition. It is particularly preferred if the same polyethylene material is used in both first and second semi-conductive compositions as this makes the recycling of the product easier.
  • the polyethylene used in the second electrically semiconductive composition is preferably therefore one described above for the first electrically semiconductive composition.
  • the semiconductive portion may be useful for the semiconductive portion to offer weaker PTC at the operating temperature interval in question. This would make the resistance more “metal like”.
  • the low density polyethylenes typically used in the second electrically semiconductive composition might be replaced by a low pressure polyolefin such as LLDPE, MDPE, HDPE or PP copolymer. These polymers tend of offer higher conductivities than LDPE and weaker PTC.
  • first and second semiconductive compositions are the same and the difference in conductance is achieved through the shape of the semiconductive portions. In another embodiment the first and second semiconductive compositions are different. In one embodiment the first and second semiconductive compositions use the same polyethylene but are different in terms of the conductive filler content.
  • the semiconductive portions should have a higher conductance that the first semiconductive composition/layer. This can also be calculated based on geometry and known VR value for given temperature. Change in conductance can therefore be achieved through manipulation of the geometry of the semiconductive portions or through manipulation of the content/nature of the conductive filler in the second electrically semiconductive composition.
  • the semiconductive portions are preferably at least two, such as at least three times thicker than the semiconductive layer.
  • the semiconductive layer is in the form of a layer and semiconductive portions are located on and protrude from the semiconductive layer.
  • the semiconductive portions should be at least two times thicker than the semiconductive layer.
  • the semiconductive layer is 2 mm in thickness then the semi conductive portions should be at least 4 mm in thickness.
  • semiconductive portions should be at least 5 times thicker than the semiconductive layer, such as 5 to 10 times thicker.
  • the semiconductor portions are significantly thicker than the semiconductive layer.
  • the semiconductor portions might be 5 Ox thicker or lOOx thicker, up to 200x thicker.
  • the semiconductor portions are 5000 micrometer in thickness.
  • the thickness of semiconductor portions does not need to be uniform. The values above might therefore apply to the thickest aspect of the semiconductive portions.
  • the semiconductive portions are subject to the same voltage and current as the semiconductive layer but heating occurs within the semiconductive layer due to higher resistance.
  • the difference in conductance may also be achieved by using more conductive filler than in the semiconductive layer or by using conductive filler(s) that are of higher conductance than ones used in the semiconductive layer.
  • the conductive pathways are semiconductive, heat will not just be generated in the semiconductive layer but also in the semiconductive portions to an extent. This, is in contrast to metal conductors, which for typical low current densities, will exhibit insignificant temperature rise due to resistive losses in the metal. This adds therefore to the overall heating capability of the heater.
  • the semiconductor portions are arranged in a regular pattern to ensure that heating within the semiconductive layer occurs evenly.
  • the semiconductor portions must be spaced apart in some way.
  • regular pattern means therefore that the motif (or motifs) is repeated in a way that is predictable.
  • the semiconductive portions are simply arranged in parallel strips on the semiconductive layer. In other embodiments, the semiconductive portions may be arranged in a zig zag, keeping the semiconductive portions equally spaced apart.
  • the person skilled in the art can devise various arrangements of the semiconductive portions on the semiconductive layer. It may be that to connect the heater and hence the semi conductive portions to a power supply a metal connector or conductor such as a wire is required to connect from the heater to the power supply but it is preferred if the heater itself is substantially free of metal conductors, such as wire metal conductors.
  • the flat sheet is free of wire like conductors running across its length or width.
  • the flat sheet may be provided with electrodes or connectors in the semiconductor portions such as to allow a connection to a power source.
  • the semiconductive portions which protrude from the semiconductive layer should however be free of wire like conductors that run along the length or width of the semiconductive portions.
  • metal wire conductors normally embedded in the semiconductor composition are replaced by portions of semiconductive material, which have higher conductance than the semiconductive layer on which they are placed.
  • connectors or electrodes which can be metal, might be required to connect the semiconductor portions to the power supply.
  • Such electrodes might be small areas of metal like a disk.
  • an electrical heater such as a flat sheet electrical heater, comprising a semiconductive layer, said semiconductive layer comprising a first electrically semiconductive composition with a positive temperature coefficient, said first semiconductive composition comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; a plurality of semi-conductive portions located on and protruding from the semiconductive layer wherein said semiconductive portions comprise a second electrically semiconductive composition with a positive temperature coefficient said second electrically semiconductive composition comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; wherein the semi-conductive portions are arranged on the semiconductive layer in a regular pattern; and wherein said semi-conductive portions have a conductance which is higher, such as at least 5x higher, than the semiconductive layer, wherein a metal conductor wire is not embedded within or located on the semiconductive portions along a substantial part of their length or width.
  • the only wire that might be present is that to allow connection from a connector to the power supply.
  • the semiconductive portions are obviously of considerably lower conductance than a metal wire. In order therefore to ensure that sufficient power is transmitted to the semiconductive layer through the semiconductive portions, it may be that semiconductive portions are provided with more than one connection point to the power supply. It is preferred that if multiple connection points are required that these are evenly spaced to try to ensure even temperature and power distribution within the semiconductor portions. Connection points should not be connected via a metal wire.
  • connection points are metallic electrodes that are adapted to connect to a metal wire from the power supply.
  • the metallic electrodes/connectors can be placed on or embedded within the semiconductor portions, typically therefore at the edge of the semi conductive portion to minimise the amount of semiconductive portion through which any connection to the power supply needs to pass.
  • These can be made of any conventional metal used for conductors such as copper or aluminium.
  • Semiconductive portions may have a thickness (or height) of 0.5 to 15 mm, such as 1.0 to 10 mm i.e. the semiconductor portions protrude from the semiconductive layer by, for example, 0.5 to 5.0 mm, such as 1.0 to 3.0 mm. It is preferred if the thickness of the semiconductive portions is at least twice that of the semiconductive layer, preferably three times the thickness. Thicknesses up to 100 times that of the semiconductive layer are possible.
  • the semiconductive portions may have a width of 0.5 to 15 mm, such as 1.0 to 10 mm. A minimum of 3.0 mm is preferred.
  • the width of each semi-conductive portion is preferably the same. Moreover, it is preferred if the width of the semiconductive portions is 0.05 to 0.5 times the distance between adjacent semiconductive conductor portions, such as 0.1 to 0.25 x. The distance between adjacent semi-conductive conductor portions is measured as the closest distance between the closest edges of adjacent portions, see scheme 1: width
  • the length of the semiconductive portions is governed by the size of the semiconductive layer onto which the semiconductive portions will be incorporated.
  • the semiconductive portions preferably extend along the majority, such as the whole, of the semiconductive layer.
  • the heater may comprise a minimum of 2 separate semiconductive portions but it may contain many more semiconductive portions.
  • the semiconductive portions are spaced apart from each and hence do not touch.
  • the semiconductive portions are preferably substantially parallel to each other.
  • Semiconductive portions should preferably be evenly spaced from each other to ensure an even temperature on application of power. By evenly spaced means that the distance between adjacent semiconductive portions is always the same.
  • the semiconductive portions are preferably arranged parallel and linear to each other. In theory however the semiconductive portions might be curved (SS shaped for example) such that they remain equidistant from each other at all times. We regard this as being “parallel”.
  • the gap between the nearest edges of the semiconductive portions is 20 to 150 mm, preferably 30 to 90 mm, such as 40 to 80 mm.
  • the heater comprises a plurality of semiconductive portions that are evenly spaced apart from and substantially parallel to each other, e.g. wherein the distance between conductors is 20 to 150 mm.
  • the semiconductive portions are in direct contact with the electrically semiconductive layer. There should not therefore be a layer separating the electrically semiconductive layer from the semiconductive portions (an adhesive may be used).
  • the semiconductive portions may be attached to the outside of the semiconductive layer. This can be achieved if the semiconductive portions are coextruded with the first electrically semi-conductive composition. It might also be achieved by laminating the semiconductive portions to a layer of first electrically semiconductive composition, e.g. using well known lamination techniques.
  • the semiconductive portions can have a rectangular shape when viewed from above cross section.
  • the semiconductive portions can have a rectangular cross section. However, if the semiconductive portion has a raised edge where it meets the semiconductive layer, this will introduce a mechanical stress. It is preferred therefore if the edges of the semiconductor portions slowly reduce in height so that a smooth interface between the semiconductive portions and layer are achieved. This is illustrated in scheme 2 or 3 : width
  • the semiconductive portions are chamfered or beveled at the interface between the semi-conductive portions and an electrically semiconductive layer. There is therefore a smooth interface between these components and a smooth increase in the thickness of the semiconductive portions until the target thickness is reached, e.g. as shown in figure 2.
  • the semiconductor portions may cover between 5%-25% of the surface area of the semiconductive layer.
  • the heater of the invention comprises a plurality of semiconductor portions.
  • the semiconductive portions are formed from a semiconductive composition. It is preferred if the semiconductors portions are all made from the same semiconductive composition to ensure that each individual semiconductive portion behaves the same when the power is applied.
  • the chemical structure therefore of the semiconductive portions is ideally all the same, i.e. each semiconductive portion contains the same polymer and the same amount of conductive filler.
  • connection point a particular part of the semiconductor portion is.
  • power enters the semiconductive portion through a connection point, typically a metal electrode connection point embedded within or attached to the semiconductor portion. This connection point is then connected to the power supply.
  • the metal conductor is melt-embedded within the semiconductive portion along its whole length. This reduces the risk of voltage drop.
  • any part of the semiconductor portion is.
  • adjacent semiconductive portions are designed so that the distance between adjacent parts of the semi-conductive portions decreases the further the parts of the semi-conductive portion are from the nearest respective connection point.
  • the semiconductor portions may therefore be arranged in a zig zag type arrangement as shown in the scheme below: To Power source To Power source
  • parts of the semiconductive portion that are directly attached to the power source are spaced apart from the adjacent semiconductive portion. Parts more remote from connection points are closer together. This means that the power transmitted to the semiconductor layer is more even.
  • the electrical heater is substantially free of metal conductors, such as metal wire conductors and comprises an electrically semiconductive layer comprising a first electrically semiconductive composition with a positive temperature coefficient comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; a plurality of semi-conductive portions located on the electrically semiconductive layer wherein said semiconductive portions comprise a second electrically conductive composition having a positive temperature coefficient and comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; said semi-conductive portions are at least three times thicker than the electrically semiconductive layer and wherein the width of each semi-conductive portion at any point is at least 3.0 mm.
  • the heater can be produced by several techniques including:
  • extrusion or lamination is most convenient. It is possible for the claimed heater to be prepared by colamination. In such a process, an electrically semi conductive layer can be prepared, e.g. via extrusion, such as cast fdm extrusion or blown film extrusion. This may be allowed to cool before colamination occurs.
  • the semi conductive portions which can also take the form of extruded films, can then be laminated onto the semiconductive layer.
  • Semiconductive portions can also be prepared via extrusion, such as cast film extrusion or blown film extrusion.
  • the films or portions required therefore may be prepared using cast or blown film extrusion.
  • a slit die is employed positioned vertically so as to extrude a fine melt film onto a highly polished, high speed chill roll.
  • the melt is pinned to the surface of the chill roll by either the pressure from an air knife or a vacuum box located close to the roll. This causes the fine film to be rapidly quenched, which improves its mechanical properties and clarity.
  • the film then travels through a further series of chill, polishing and nip rolls, which help to draw the film down to the correct thickness, before its edges are trimmed and it is wound onto a drum for storage.
  • the molten plastic from the extruder passes through an annular die and emerges as a thin tube.
  • a supply of air to the inside of the tube prevents it from collapsing and may be used to inflate it to a larger diameter.
  • the bubble consists of molten plastic but a jet of air around the outside of the tube (cooling ring) promotes cooling and at a certain distance from the die exit, a freeze line can be identified.
  • the cooled film passes through collapsing guides and nip rolls before being taken off to storage drums or, for example, gussetted and cut to length.
  • a preferred key aspect of the invention is that the claimed heater can be prepared using coextrusion.
  • the heater of the invention is preferably not therefore a typical laminate where the various layers are prepared separately and laminated together, perhaps using an adhesive. We do not require adhesive in our product.
  • the heater of the invention can therefore be prepared continuously.
  • the semiconductive composition can be co-extruded with the semiconductive portions.
  • the heater of the invention is cheap. It is also thin and flexible.
  • the semiconductive portions are preferably provided with at least one connecting point to allow connection of the semiconductive portions to a power source.
  • a connection point will be a metallic electrode adapted such that a metal conductor from the power source can be readily connected thereto.
  • the semiconductive portions may comprise a plurality of such connection points.
  • the connection points should be evenly spaced apart to ensure that even heating in the semiconductive layer to which the semiconductive portions are in contact.
  • These connecting points can be attached to or embedded within the semiconductive portions when the polymer is in melt form.
  • the process comprises the steps of (a)
  • step (a) a meltmix of the second electrically semiconductive composition obtained from step (a), to form a heater having a semiconductive layer comprising said first electrically semiconductive composition with a positive temperature coefficient comprising a polyethylene, polypropylene or a mixture thereof and a conductive filler; a plurality of semi-conductive portions comprising said second semiconductive composition located on and protruding from the first electrically semiconductive layer wherein said second semiconductive composition has a positive temperature coefficient and comprise a polyethylene, polypropylene or a mixture thereof and a conductive filler; wherein the semi-conductive portions are arranged on the semiconductive layer in a regular pattern; and wherein said semi-conductive portions have a conductance which is higher, such as at least 5 higher than the electrically semiconductive layer.
  • This process can be readily adapted to include further layers above or below the semiconductive layer.
  • a second layer as defined herein can also be coextruded above or below the electrically semiconductive layer.
  • a second layer can be laminated above or below the electrically semiconductive layer.
  • crosslinking conditions can then be applied to cause a crosslinking reaction. It is preferred however if no crosslinking reaction is used.
  • Melt mixing means mixing above the melting point of at least the major polymer component(s) of the mixture and is typically carried out in a temperature of at least 10-15°C above the melting or softening point of polymer component(s).
  • coextrusion means herein that two or more layers are extruded in the same extrusion step.
  • coextrusion means that all or part of the layer(s) are formed simultaneously using one or more extrusion heads. For instance triple extrusion can be used for forming three layers.
  • the heater of the invention is flexible. It is preferably in the form of a flat sheet although such a flat sheet is flexible and can adopt the shape of a substrate onto which it is applied or can be formed into a cylinder.
  • the heater can be prepared in any desired dimensions.
  • the width of the heater can be adjusted readily to any possible use.
  • the width may be a function of the coextrusion apparatus and sheets from 5 cm to 5 metres can be produced readily.
  • the heater of the invention can be utilised in many fields. Applications of the technology described herein are therefore widespread.
  • the heater of the invention may therefore be employed within an item of furniture such as a screen, chair or sofa.
  • the heater of the invention might be used in a heated garment.
  • Heated garments available today have small wires (often made of brittle carbon fibres) built into them. They heat up when a low voltage electric current is passed through.
  • the heaters of the invention are ideally suited for use in both these applications.
  • the heater may also be used in a blanket. A major concern with electric heating blankets on the market today is fire risk. These blankets tend to overheat. Using the heater of the present invention that risk is eliminated.
  • the invention provides a textile comprising the heater of the invention.
  • Radiators are large, immobile and often unattractive. In many parts of the world, radiators are hidden behind more aesthetically pleasing covers of various designs. These covers may also reduce noise or protect against the touching of radiators that get excessively hot. But hiding the radiator is not efficient because adding a radiator cover slows the movement of heat out of the radiator and into the room. The rate of heat loss out through the building’s exterior wall is likely to be increased.
  • the heaters of the invention can replace radiators or be used in walls, under floors, in ceilings as heaters.
  • the heaters could even be included within a carpet or rug or other floor covering.
  • Electric cars generate next to no heat as opposed to conventional passenger vehicles, which produce more than enough engine heat to heat the interior. An additional electric heater is therefore required in an electric vehicle to heat the interior.
  • This heater is supplied with power by the same battery that provides the engine with energy. This can reduce the maximum possible drive distance by a considerable amount.
  • the present invention might be used to heat inner contact surfaces such as steering wheel, armrest, door panels, seats within the vehicle. More efficient heating can be envisaged compared to heating the entire inner volume of the car, especially for short journeys.
  • the heater of the invention could be used to prevent ice or snow build up on a critical surface such as a solar panel. Heaters might therefore have utility in deicing operations. Other surfaces might be wing mirrors.
  • the heaters are flexible and might be wrapped around pipes to prevent liquid freezing therein. Heaters can furthermore be used to keep fluids heated e.g. in swimming pools or liquid containers. The skilled person can device many applications of these versatile heaters.
  • Figure 1 shows a flat sheet heater of the invention viewing from above and in cross section.
  • the heater has parallel semiconductive portions which are located on and protrude from the semiconductive layer.
  • the semiconductive portions are spaced apart, e.g. by 8 cm and may be 2 to 3 mm in height or thicker.
  • the semiconductive composition may be formed from EVA or EBA.
  • Figure 2 shows a flat sheet heater of the invention viewing from above and in cross section.
  • the heater has parallel semiconductive portions which are located on and protrude from the semiconductive layer.
  • the semiconductive portions are spaced apart, e.g. by 8 cm and may be 2 to 3 mm in height.
  • the semiconductive composition may be formed from EVA or EBA.
  • the adjacent edges of the semiconductive portions are bevelled to create a smooth increase in gradient from the semiconductive composition to the full height of the semiconductive portion mainly in order to reduce mechanical stress.
  • Figure 3 shows a flat sheet heater of the invention viewing from above.
  • the heater has semiconductive portions which are located on and protrude from the semiconductive layer.
  • the semiconductive composition may be formed from EVA or EBA.
  • the heater is provided with connection points to a voltage source. The part of the semiconductive portions nearest these respective connection points are spaced far apart from the adjacent semiconductive portion but as the distance from the connection points increases the adjacent semiconductive portions are moved closer to each other creating therefore the ⁇ > type arrangement.
  • the use of these non-parallel semiconductive portions compensates for the voltage drop that occurs along the semiconductive portions as the distance from the connection points and hence the source of power increases.
  • Figure 4a and Figure 4b show a flat sheet heater of figure 1 viewing from above and in cross section.
  • the heater has parallel semiconductive portions (2) which are located on and protrude from the semiconductive layer (1).
  • the semiconductive portions are spaced apart, e.g. by 8 cm and may be 2 to 3 mm in height or thicker.
  • the semiconductive composition may be formed from EVA or EBA.
  • the semiconductive portions contains metal connectors or electrodes (3), e.g. in the form of disks that can be connected to a power supply via an electrical wire 4.
  • Metal conductor wires do not however pass through a substantial portion of the semiconductive portions.
  • the melt flow rate (MFR) is determined according to ISO 1133 and is indicated in g/10 min.
  • the MFR is an indication of the flowability, and hence the processability, of the polymer.
  • the MFR is determined at 125°C for polyethylene present within the semiconductive composition. It may be determined at loading of 21.6 kg (MFR21).
  • Example 1 - Semiconductive layer A film was prepared using a 3 -layer cast film lab line manufactured by Collin.
  • the line is equipped with a 30 mm core extruder and two 25 mm outer extruders, each in a length of 30 / LD.
  • the die- width is 300 mm and equipped with a flexible die-lip in a range of 0,5-1, 2 mm which results in a final film width of ⁇ 250 mm.
  • the chill roll unit consists of three polished chill rolls tempered in a range of 15 - 120 °C. The film was wounded to 3 inch cores.
  • EVAI was extruded in layers 1 to 3 to form a monolayer.
  • the overall film thickness was 125 pm.
  • the film was prepared using a 3 -layer cast film lab line manufactured by Collin.
  • the line is equipped with a 30 mm core extruder and two 25 mm outer extruders, each in a length of 30 / LD.
  • the die- width is 300 mm and equipped with a flexible die-lip in a range of 0,5-1, 2 mm which results in a final film width of ⁇ 250 mm.
  • the chill roll unit consists of three polished chill rolls tempered in a range of 15 - 120 °C.
  • the film was wounded to 3 inch cores.
  • EVAI was extruded in layers 1 to 3 to form a monolayer.
  • the overall film thickness was 300 pm but can be cut to desired dimensions for a semiconductor portion strip.
  • the semiconductive portions of example 2 were laminated onto the semiconductive layer of example 1 by preheating followed by heat lamination.

Landscapes

  • Resistance Heating (AREA)

Abstract

L'invention concerne un dispositif de chauffage électrique, tel qu'un dispositif de chauffage électrique à feuille plate, comprenant une couche semi-conductrice, ladite couche semi-conductrice comprenant une première composition électriquement semi-conductrice présentant un coefficient de température positif, ladite première composition semi-conductrice comprenant un polyéthylène, un polypropylène ou un mélange de ceux-ci et une charge conductrice; une pluralité de parties semi-conductrices situées sur la couche électriquement semi-conductrice, et faisant saillie à partir de celle-ci, lesdites parties semi-conductrices comprenant une seconde composition électriquement semi-conductrice présentant un coefficient de température positif, ladite seconde composition semi-conductrice comprenant un polyéthylène, un polypropylène ou un mélange de ceux-ci et une charge conductrice; les parties semi-conductrices étant agencées sur la couche semi-conductrice selon un motif régulier; et lesdites parties semi-conductrices étant au moins deux fois plus épaisses que la couche semi-conductrice.
PCT/EP2024/086391 2023-12-13 2024-12-13 Dispositif de chauffage autorégulé Pending WO2025125647A1 (fr)

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EP23216472 2023-12-13
EP23216472.3 2023-12-13

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US3922335A (en) 1974-02-25 1975-11-25 Cabot Corp Process for producing carbon black
US4247756A (en) 1979-06-29 1981-01-27 Victor Cucinotta Heated floor mat
US4391789A (en) 1982-04-15 1983-07-05 Columbian Chemicals Company Carbon black process
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EP1275274A1 (fr) 2000-01-28 2003-01-15 Polyohm AB Dispositif de chauffage par le sol
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US20160264809A1 (en) * 2015-03-09 2016-09-15 1-Material Inc Polymeric Positive Temperature Coefficient Composition with Improved Temperature Homogeneity
US20210112631A1 (en) 2019-10-15 2021-04-15 Arte Reverse Engineering Gbr Heating element for a surface component of a motor vehicle
WO2021188595A1 (fr) 2020-03-16 2021-09-23 Neptech, Inc. Couverture chauffante
WO2022129251A1 (fr) 2020-12-15 2022-06-23 Borealis Ag Dispositif de chauffage autorégulé

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3401020A (en) 1964-11-25 1968-09-10 Phillips Petroleum Co Process and apparatus for the production of carbon black
US3922335A (en) 1974-02-25 1975-11-25 Cabot Corp Process for producing carbon black
CA1150754A (fr) * 1979-05-10 1983-07-26 George M. Gale Elements chauffants souples, et methodes de production connexes
US4247756A (en) 1979-06-29 1981-01-27 Victor Cucinotta Heated floor mat
US4391789A (en) 1982-04-15 1983-07-05 Columbian Chemicals Company Carbon black process
EP0100919A1 (fr) 1982-08-11 1984-02-22 Allied Corporation Alliage à base de nickel présentant une résistance mécanique élevée pour le brasage à températures relativement basses
EP0340361B1 (fr) * 1988-05-03 1995-09-20 Raychem Corporation Dispositif électrique comprenant un élément résistif PTC en polymère
WO1993008222A1 (fr) 1991-10-22 1993-04-29 Neste Oy Copolymeres d'ethylene insature/diene non conjugue et preparation de ces copolymeres par polymerisation de radicaux
US5451747A (en) 1992-03-03 1995-09-19 Sunbeam Corporation Flexible self-regulating heating pad combination and associated method
EP0629222A1 (fr) 1992-03-05 1994-12-21 Cabot Corporation Procede de production de noirs de carbone et nouveaux noirs de carbone
EP1009196A1 (fr) * 1997-01-13 2000-06-14 Idemitsu Kosan Co., Ltd. Element chauffant planar
US7053344B1 (en) 2000-01-24 2006-05-30 Illinois Tool Works Inc Self regulating flexible heater
EP1275274A1 (fr) 2000-01-28 2003-01-15 Polyohm AB Dispositif de chauffage par le sol
US7250586B2 (en) 2000-12-23 2007-07-31 Braincom Ag Surface heating system and method for producing it and a heatable object
SE529543C2 (sv) * 2005-11-06 2007-09-11 Claes-Goeran Gustafsson Bred självreglerande värmematta process
WO2008133562A1 (fr) 2007-04-30 2008-11-06 Intelliohm Ab Dispositif de chauffage
WO2014188190A1 (fr) 2013-05-21 2014-11-27 Heat Trace Limited Chauffage électrique
US20160264809A1 (en) * 2015-03-09 2016-09-15 1-Material Inc Polymeric Positive Temperature Coefficient Composition with Improved Temperature Homogeneity
US20210112631A1 (en) 2019-10-15 2021-04-15 Arte Reverse Engineering Gbr Heating element for a surface component of a motor vehicle
WO2021188595A1 (fr) 2020-03-16 2021-09-23 Neptech, Inc. Couverture chauffante
WO2022129251A1 (fr) 2020-12-15 2022-06-23 Borealis Ag Dispositif de chauffage autorégulé

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