EP0918638A1 - Verfahren zum herstellen von laminaten aus leitenden polymerzusammensetzungen - Google Patents
Verfahren zum herstellen von laminaten aus leitenden polymerzusammensetzungenInfo
- Publication number
- EP0918638A1 EP0918638A1 EP97934350A EP97934350A EP0918638A1 EP 0918638 A1 EP0918638 A1 EP 0918638A1 EP 97934350 A EP97934350 A EP 97934350A EP 97934350 A EP97934350 A EP 97934350A EP 0918638 A1 EP0918638 A1 EP 0918638A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- laminate
- polymeric component
- mixing apparatus
- sheet
- polymeric
- 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- Withdrawn
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
- B32B15/085—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
- B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
- B32B37/14—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
- B32B37/15—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state
- B32B37/153—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state at least one layer is extruded and immediately laminated while in semi-molten state
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41D—APPARATUS FOR THE MECHANICAL REPRODUCTION OF PRINTING SURFACES FOR STEREOTYPE PRINTING; SHAPING ELASTIC OR DEFORMABLE MATERIAL TO FORM PRINTING SURFACES
- B41D7/00—Shaping elastic or deformable material, e.g. rubber, plastics material, to form printing surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41K—STAMPS; STAMPING OR NUMBERING APPARATUS OR DEVICES
- B41K1/00—Portable hand-operated devices without means for supporting or locating the articles to be stamped, i.e. hand stamps; Inking devices or other accessories therefor
- B41K1/02—Portable hand-operated devices without means for supporting or locating the articles to be stamped, i.e. hand stamps; Inking devices or other accessories therefor with one or more flat stamping surfaces having fixed images
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2305/00—Condition, form or state of the layers or laminate
- B32B2305/30—Fillers, e.g. particles, powders, beads, flakes, spheres, chips
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
- B32B2307/202—Conductive
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/704—Crystalline
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2457/00—Electrical equipment
Definitions
- This invention relates to a method of making a laminate comprising a conductive polymer composition and electrical devices comprising such laminate.
- Conductive polymer compositions which exhibit PTC (positive temperature coefficient of resistance) behavior are well-known for use in electrical devices such as circuit protection devices.
- Such compositions comprise a polymeric component, and dispersed therein, a particulate conductive filler such as carbon black or metal.
- the amount and type of filler in the composition are determined by the required resistivity for each application, as well as by the nature of the polymeric component.
- Compositions suitable for use in circuit protection devices have low resistivities at room temperature, e.g. less than 100 ohm-cm, and generally comprise relatively high levels of conductive filler. When such highly filled compositions are prepared by conventional methods such as melt-mixing, they are subject to substantial shear.
- Such sh&ar generates heat, which may degrade the polymer and result in an increased resistivity. Further shear and/or heat exposure results from the subsequent processing steps, e.g. extrusion, melt-forming, and attachment of electrodes, e.g. by lamination.
- Conventional processing techniques provide that some of these steps, e.g. extrusion and lamination, can be performed in a continuous process, but it is common, due to the desire to ensure adequate dispersion of the filler in the polymer, to divide the manufacturing process into several discrete, i.e. separate, steps. The more times the composition is heated, cooled, and subjected to shear, the greater the chances of degradation and resistivity change.
- Compositions with low resistivity are desirable for use in circuit protection devices which respond to changes in ambient temperature and/or current conditions. Under normal conditions, a circuit protection device remains in a low temperature, low resistance state in series with a load in an electrical circuit. When exposed to an overcurrent or overtemperature condition, however, the device increases in resistance, effectively shutting down the current flow to the load in the circuit. For many applications it is desirable that the device have as low a resistance as possible in order to minimize the effect on the resistance of the electrical circuit during normal operation.
- low resistance devices can be made by changing dimensions, e.g. making the distance between the electrodes very small or the device area very large, small devices are preferred because they occupy less space on a circuit board and generally have desirable thermal properties.
- the most common technique to achieve a small device is to use a composition that has a low resistivity.
- the resistivity of a conductive polymer composition can be decreased by adding more conductive filler, but this process can affect the processability of the composition, e.g. by increasing the viscosity.
- the addition of conductive filler generally reduces the size of the PTC anomaly, i.e. the size of the increase in resistivity of the composition in response to an increase in temperature, generally over a relatively small temperature range.
- the required PTC anomaly is determined by the applied voltage and the application. It is therefore necessary to minimize the effects of processing which result in resistivity increases, in order to achieve a composition with acceptable size and electrical properties.
- the method of the invention allows the elimination of the pelletizing step, along with drying of the pellets before the sheet- forming step. This means that the composition is exposed to one less heating and shearing process.
- this invention provides a method of making a laminate from a conductive polymer composition which comprises (i) a polymeric component and (ii) a particulate conductive filler dispersed in the polymeric component, said method comprising
- steps (A) to (E) being conducted sequentially in a single continuous procedure.
- this invention provides an electrical device which
- ( 1 ) comprises (a) a resistive element which is composed of a conductive polymer composition which exhibits PTC behavior and which comprises (i) a polymeric component which has a melting temperature T m , and (ii) dispersed in the polymeric component a particulate conductive filler; and (b) two electrodes which (i) are attached to the resistive element, (ii) comprise metal foil, and (iii) can be connected to a source of electrical power;
- steps (A) to (E) being conducted sequentially in a single continuous procedure.
- the method of the invention is used to m,ake a laminate of a conductive polymer composition.
- the conductive polymer composition comprises a polymeric component, and, dispersed in the polymeric component, a particulate conductive filler.
- the polymeric component of the composition comprises one or more polymers, one of which is preferably a crystalline polymer having a crystallinity of at least 20% in its unfilled state as measured by a differential scanning calorimeter.
- Suitable crystalline polymers include polymers of one or more olefins, particularly polyethylene such as high density polyethylene; copolymers of at least one olefin and at least one monomer copolymerisable therewith such as ethylene/acrylic acid, ethylene/ethyl acrylate, ethylene/vinyl acetate, and ethylene/butyl acrylate copolymers; melt-shapeable fluoropolymers such as polyvinylidene fluoride and ethylene/tetrafluoroethylene copolymers (including terpolymers); and blends of two or more such polymers.
- the polymeric component has a melting temperature, as measured by the peak of the endotherm of a differential scanning calorimeter, of T .
- T m is defined as the temperature of the highest temperature peak.
- the polymeric component generally comprises 40 to 90% by volume, preferably 45 to 80% by volume, especially 50 to 75% by volume of the total volume of the composition.
- the particulate conductive filler which is dispersed in the polymeric component may be any suitable material, including carbon black, graphite, metal, metal oxide, conductive coated glass or ceramic beads, particulate conductive polymer, or a combination of these.
- the filler may be in the form of powder, beads, flakes, fibers, or any other suitable shape.
- the quantity of conductive filler needed is based on the required resistivity of the composition and the resistivity of the conductive filler itself. For many compositions the conductive filler comprises 10 to 60% by volume, preferably 20 to 55% by volume, especially 25 to 50% by volume of the total volume of the composition.
- the conductive polymer composition may comprise additional components, such as antioxidants, inert fillers, nonconductive fillers, radiation crosslinking agents (often referred to as prorads or crosslinking enhancers, e.g. triallyl isocyanurate), stabilizers, dispersing agents, coupling agents, acid scavengers (e.g. CaCO ⁇ ), or other components. These components generally comprise at most 20% by volume of the total composition.
- the composition generally exhibits positive temperature coefficient (PTC) behavior, i.e. it shows a sharp increase in resistivity with temperature over a relatively small temperature range, although the method of the invention may be used to prepare compositions which exhibit zero temperature coefficient (ZTC) behavior.
- PTC positive temperature coefficient
- ZTC zero temperature coefficient
- the term "PTC” is used to mean a composition or device which has an R14 value of at least 2.5 and/or an Ri 00 value of at least 10, and it is preferred that the composition or device should have an R30 value of at least 6, where R14 is the ratio of the resistivities at the end and the beginning of a 14°C range, RlOO is the rat i° of the resistivities at the end and the beginning of a 100°C range, and R30 is the ratio of the resistivities at the end and the beginning of a 30°C range.
- compositions used in devices of the invention which exhibit PTC behavior show increases in resistivity which are much greater than those minimum values. It is preferred that compositions used to form devices of the invention have a PTC anomaly at at least one temperature over the range from 20°C to (T m + 5°C) of at least 10 ⁇ , preferably at least l ⁇ -5, particularly at least 10 ⁇ , especially at least lO ⁇ -S, i.e. the log[resistance at (Tj m +
- 5°C/resistance at 20°C] is at least 4.0, preferably at least 4.5, particularly at least 5.0, especially at least 5.5. If the maximum resistance is achieved at a temperature T x that is below (T + 5°C), the PTC anomaly is determined by the log(resistance at T x /resistance at 20°C).
- the resistivity of the composition depends on the application and what type of electrical device is required.
- the composition has a resistivity at 20°C, p20 > of at most 100 ohm-cm, preferably at most 50 ohm-cm, more preferably at most 20 ohm-cm, particularly at most 10 ohm-cm, more particularly at most 5 ohm-cm, especially at most 2.0 ohm-cm, most especially at most 1.0 ohm-cm.
- the resistivity of the conductive polymer composition is preferably higher, e.g.
- Suitable conductive polymer compositions are disclosed in U.S. Patent Nos. 4,237,441 (van Konynenburg et al), 4,388,607 (Toy et al), 4,534,889 (van Konynenburg et al), 4,545,926 (Fouts et al), 4,560,498 (Horsma et al), 4,591,700 (Sopory), 4,724,417 (Au et al), 4,774,024 (Deep et al), 4,935,156 (van Konynenburg et al), 5,049,850 (Evans et al), and 5,250,228 (Baigrie et al), 5,378,407 (Chandler et al), 5,451,919 (Chu et al), and 5,582,770 (Chu et al), and in International Publications Nos.
- the method of the invention comprises five steps, steps (A) to (E), which are conducted sequentially in a single continuous procedure. Additional process steps, e.g. heat- treatment or irradiation, may be conducted between two steps of the invention so long as the process remains continuous. At least parts of two steps may be conducted simultaneously, e.g. transporting the molten mixture through a die (step (C)) which has a shape which forms the molten mixture into a polymeric sheet (step (D)).
- steps (A) to (E) which are conducted sequentially in a single continuous procedure. Additional process steps, e.g. heat- treatment or irradiation, may be conducted between two steps of the invention so long as the process remains continuous. At least parts of two steps may be conducted simultaneously, e.g. transporting the molten mixture through a die (step (C)) which has a shape which forms the molten mixture into a polymeric sheet (step (D)).
- step (A) the polymeric component and the particulate conductive filler are loaded into a mixing apparatus.
- both the polymeric component and the conductive filler . are in the form of dry powders, flakes, fibers, or pellets which can be readily fed into the mixing apparatus.
- these two components can be fed separately into the mixing apparatus, preferably the polymeric component and the conductive filler are "premixed" in the dry state, e.g. by means of a blender or mixer such as a HenschelTM mixer, to improve the uniformity and flow of the components during the loading step.
- Additional components in the form of powder, pellets, or liquid, may be premixed with the polymer component and the particulate component, or may be added at different points in the process. Loading may be achieved by any means, although loss-in-weight feeders such as those sold by K-Tron America under the tradename "K-Tron", are preferred to ensure consistent feeding into the apparatus.
- the mixing apparatus is preferably an extruder, although other types of mixing equipment, including internal mixers such as BanburyTM mixers, BrabenderTM mixers, and MoriyamaTM mixers, may be used with suitable attachments for conveying material to complete the required steps of the invention.
- Suitable extruders include single screw extruders, co-rotating twin screw extruders, counter-rotating twin screw extruders, or reciprocating single screw extruders, e.g. a BussTM kneader.
- various additives e.g. crosslinking agents such as peroxide
- crosslinking agents such as peroxide
- the method of the invention is particularly suited for in-line chemical crosslinking. The continuous procedure allows the crosslinking agent to be added just before the material is transported through a die.
- step (B) the polymeric component and the conductive filler are mixed in the mixing apparatus to form a molten mixture, i.e. one which has a temperature above the melting temperature T m of the polymeric component.
- the conductive filler, as well as other components such as inorganic fillers or pigments, is dispersed in the polymeric component.
- the screw of an extruder may be designed to have mixing or kneading sections, as well as conveying sections. For example, we have found that incorporating kneading sections in at least 10% of the total screw length for a corotating twin screw extruder has produced acceptable dispersion.
- the ratio of the screw length to its diameter i.e. the L/D ratio
- the ratio of the screw length to its diameter is at least 10:1, preferably at least 15:1, p.articul.arly at least 20:1, especially at least 30:1, e.g. 40:1, in order to achieve adequate dispersion of the conductive filler.
- the mixing apparatus may be heated, e.g. electrically or by oil, in one or more sections (zones).
- a vacuum apparatus, to remove volatiles generated during mixing, can be positioned appropriately in combination with the mixing apparatus.
- step (C) the molten mixture is transported from the mixing apparatus through a die.
- the term "die” is used in this specification to mean any element which has an orifice through which the molten material can pass.
- a die may be a mold, a nozzle, or an article with an opening or gap of a particular shape through which the molten material passes.
- the die can be attached directly to an exit port of the mixing apparatus, e.g. by means of an adapter, or it may be separated from the mixing apparatus by one or more pieces of equipment, e.g. a gear pump or a vacuum apparatus.
- the mixing apparatus is an extruder, the "transporting" of the molten mixture occurs during the normal operation of the extruder. Other means of transporting the molten mixture may be required if other types of mixing apparatus are used.
- step (D) the molten mixture is formed into a polymeric sheet.
- This can be achieved easily by extrusion through a sheet die or by calendering the molten mixture, i.e. passing the molten mixture between rollers or plates to thin it into a sheet.
- the thickness of the calendered sheet is determined by the distance between the plates or rollers, as well as the rate at which the rollers .are rotating.
- the polymeric sheet has a thickness of 0.025 to 3.8 mm (0.001 to 0.150 inch), preferably 0.051 to 2.5 mm (0.002 to 0.100 inch).
- the polymeric sheet may have any width. The width is determined by the shape and width of the die or the volume of material and rate of calendering, and is often 0.15 to 0.31 m (6 to 12 inches).
- a laminate is formed by attaching metal foil to at least one side, preferably to both sides, of the polymeric sheet.
- the metal foil layer(s) act(s) as an electrode.
- the metal foil generally has a thickness of at most 0.13 mm (0.005 inch), preferably at most 0.076 mm (0.003 inch), particularly at most 0.051 mm (0.002 inch), e.g. 0.025 mm (0.001 inch).
- the width of the metal foil is generally approximately the same as that of the polymeric sheet, but for some applications, it may be desirable to apply the metal foil in the form of two or more narrow ribbons, each having a width much less than that of the polymeric sheet.
- Suitable metal foils include nickel, copper, brass, aluminum, molybdenum, and alloys, or foils which comprise two or more of these materials in the same or different layers. Particularly suitable metal foils have at least one surface that is electrodeposited, preferably electrodeposited nickel or copper. Appropriate metal foils are disclosed in U.S. Patents Nos. 4,689,475 (Matthiesen), and 4,800,253 (Kleiner et al), and in International Publication No. WO95/34081 (Raychem Corporation, published December 14, 1995). In a preferred embodiment, the metal foil contacts the polymeric sheet .and is then passed through rollers, e.g. via a roll stack, to promote good lamination of the foil to the polymer.
- the distance between the die and the roll stack be relatively small, e.g. less than 0.61 m (2 feet), preferably less than 0.31 m (1 foot).
- an adhesive composition i.e. a tie layer
- the laminate resulting from step (E) may be wound onto a reel or sliced into discrete pieces for further processing or storage.
- the thickness of the laminate is generally 0.076 to 4.1 mm (0.003 to 0.160 inch).
- the method of the invention can be used to produce a laminate with more than one polymeric sheet by using two or more mixing apparatus/tr ⁇ msporting/forming set-ups which produce polymeric sheets based on the same or different polymeric components and conductive fillers.
- the laminate When the laminate comprises two metal foils, it can be used to form an electrical device, particularly a circuit protection device.
- the device may be cut from the laminate in step (F).
- the term "cut” is used to include any method of isolating or separating the device from the laminate, e.g. dicing, punching, shearing, cutting, etching and/or breaking as described in International Publication No. WO95/34084 (Raychem Corporation, published December 4, 1995), or any other suitable means.
- Step (F) may, but need not, be part of the single continuous procedure of steps (A) to (E). Additional metal leads, e.g. in the form of wires or straps, can be attached to the foil electrodes to allow electrical connection to a circuit.
- elements to control the thermal output of the device e.g. one or more conductive terminals
- These terminals can be in the form of metal plates, e.g. steel, copper, or brass, or fins, that are attached either directly or by means of an intermediate layer such as solder or a conductive adhesive, to the electrodes.
- an intermediate layer such as solder or a conductive adhesive
- Crosslinking can be accomplished by chemical means or by irradiation, e.g. using an electron beam or a Co ⁇ O ⁇ irradiation source.
- the level of crosslinking depends on the required application for the composition, but is generally less than the equivalent of 200 Mrads, and is preferably substantially less, i.e. from 1 to 20 Mrads, preferably from 1 to 15 Mrads, particularly from 2 to 10 Mrads for low voltage (i.e. less than 60 volts) circuit protection applications.
- Generally devices are crosslinked to the equivalent of at least 2 Mrads.
- Various processing procedures for devices are described in International Publication No. WO96/29711 (published September 26, 1996).
- Devices of the invention are preferably circuit protection devices that generally have a resistance at 20°C, R20- of less than 100 ohms, preferably less than 50 ohms, particularly less than 20 ohms, more particularly less than 10 ohms, especially less than 5 ohms, most especially less than 1 ohm.
- laminate prepared by the method of the invention comprises a conductive polymer composition which can have a low resistivity, it can be used to produce devices with very low resistances, e.g. 0.001 to 0.100 ohm.
- Devices which are heaters generally have a resistance of at least 100 ohms, preferably at least 250 ohms, particularly at least 500 ohms.
- the laminate made by the method of this invention can be used for any type of electrical device, e.g. heaters or sensors, as well as circuit protection devices.
- the invention is illustrated by the following Examples in which Examples 1 , 2, 4, 6, 8, and 10 are Comparative Examples.
- the mixed dry ingredients were introduced into a corotating twin screw extruder using a screw with an L/D ratio of 40: 1 (ZSK-40, available from Werner-Pfleiderer), mixed, extruded into strands, and cut into pellets.
- ZSK-40 available from Werner-Pfleiderer
- Example 1 the pellets were dried at 80°C (175°F) for at least 24 hours and then were extruded through a 25 mm (1 inch) single screw extruder fitted with a nozzle with a diameter of 9.5 mm (0.375 inch). The molten material was extruded from the nozzle and fed onto a roll stack positioned about 25 mm (1 inch) from the nozzle end.
- the roll stack was used to both calender the material into a sheet with a thickness of about 0.250 mm (0.010 inch) and a width of about 114 to 152 mm (4.5 to 6.0 inches) and to attach electrodeposited nickel/copper foil (Type 31, 1-oz foil having a thickness of about 0.044 mm (0.0017 inch) available from Fukuda) to both sides of the calendered sheet.
- the resulting laminate had a thickness of about 0.34 mm (0.0135 inch).
- the pellets were extruded through a counter-rotating/co- rotating twin-screw extruder (ZSE-27, available from Leistritz) in a corotation mode using a screw with no kneading elements and having an L/D ratio of 40: 1.
- the extruder was fitted with a gear pump having a capacity of 10 cm /revolution (Pep II, available from Zenith) and then with a nozzle as above.
- the material was extruded, calendered, and laminated following the same procedure as for Example 1.
- the mixed dry ingredients were introduced into a ZSE-27 extruder used in a corotation mode, and having a screw configuration in which 11% of the total screw length was kneading elements.
- the screw had an L:D ratio of 40:1.
- the extruder was fitted with a gear pump and nozzle as in Examples 2, 4, and 6.
- the material was mixed, and the mixed material was extruded through the gear pump and nozzle, calendered, and laminated following the same procedure as for Examples 2, 4, and 6.
- the laminate was irradiated in a continuous process using a 3.5
- MeV electron beam to a total of 7.5 Mrad.
- the laminate was then coated in a continuous process with solder (using a solder temperature of about 250°C), and devices with dimensions of 1 1 x 15 mm (0.43 x 0.59 inch) were punched from the laminate.
- solder using a solder temperature of about 250°C
- devices with dimensions of 1 1 x 15 mm (0.43 x 0.59 inch) were punched from the laminate.
- Two 20 AWG tin-coated copper leads about 25 mm (1 inch) long were attached to the device and the device was temperature cycled at a rate of 10°C/minute from 40°C to 160°C to 40°C for six cycles, with a 30 minute dwell time at the temperature extremes for each cycle.
- Example 1 devices with dimensions as above were cut from laminate that had been irradiated as discrete pieces and had not been solder-coated. Leads were attached and the devices were temperature cycled as above.
- composition in weight% (density in g/cm )
- the device resistance at 20°C was measured and the resistivity calculated.
- the resistance versus temperature properties of the device were determined by positioning the device in an oven and measuring the resistance at intervals over the temperature range 20 to 200 to 20°C.
- the height of the PTC anomaly, PTC was determined after the first temperature cycle as log(resistance at 175°C/resistance at 20°C).
- the mixed dry ingredients were introduced into a 70 mm (2.75 inch) Buss kneader (a reciprocating single screw extruder), mixed, extruded into strands, and cut into pellets.
- a ZSE-27 extruder in a corotation mode with a screw having no kneading elements and an L:D ratio of 40: 1 was fitted with a gear pump at the exit port of the extruder as in Example 2.
- the gear pump was attached to a sheet die having an opening 152 mm (6 inch) wide and 0.038 mm (0.0015 inch) thick.
- the pellets were extruded through the sheet die to form a polymeric sheet and the polymeric sheet was drawn from the die onto a roll stack spaced about 12.7 mm (0.5 inch) from the die lip and having rubber-coated rollers heated to about 155°C.
- Nickel/copper foil as described in Example 1 was laminated onto the polymeric sheet.
- the resulting laminate had a thickness of about 0.127 mm (0.005 inch).
- the mixed dry ingredients were introduced into a ZSE-27 extruder used in a corotation mode, and having a screw configuration in which 11% of the total screw length was kneading elements and the L:D ratio was 40:1.
- the material was mixed in the extruder, and continuously extruded and laminated using the gear pump, die, and lamination process described for Example 8.
- Laminate was solder coated in a continuous (using a solder temperature of about 220°C), and devices with dimensions of 5 x 12 mm (0.20 x 0.47 inch) were punched from the laminate.
- the devices were heat-treated in a process that exposed them to a temperature of 185 to 215°C for about 4 seconds.
- the devices were then crosslinked to 10 Mrad using a Co gamma irradiation source.
- Nickel leads with dimensions of 0.13 x 5 x 13.5 mm (0.005 x 0.2 x 0.5 inch) were attached to the electrodes on both sides of the device by solder reflow and the devices were temperature cycled six cycles from -40°C to 85°C with a 30 minute dwell time at the temperature extremes.
- composition in weight % (density in ⁇ g/cm )
- HDPE (0.954) 5.0 5.0 4.8 4.8
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Ceramic Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Dispersion Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Thermistors And Varistors (AREA)
- Laminated Bodies (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US69175196A | 1996-08-01 | 1996-08-01 | |
US691751 | 1996-08-01 | ||
PCT/US1997/013419 WO1998005503A1 (en) | 1996-08-01 | 1997-07-30 | Method of making a laminate comprising a conductive polymer composition |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0918638A1 true EP0918638A1 (de) | 1999-06-02 |
Family
ID=24777820
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97934350A Withdrawn EP0918638A1 (de) | 1996-08-01 | 1997-07-30 | Verfahren zum herstellen von laminaten aus leitenden polymerzusammensetzungen |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP0918638A1 (de) |
JP (1) | JP2000515448A (de) |
KR (1) | KR20000029763A (de) |
CN (2) | CN1090087C (de) |
AU (1) | AU3742997A (de) |
CA (1) | CA2261895A1 (de) |
TW (1) | TW343423B (de) |
WO (1) | WO1998005503A1 (de) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6306323B1 (en) | 1997-07-14 | 2001-10-23 | Tyco Electronics Corporation | Extrusion of polymers |
US6589299B2 (en) * | 2001-02-13 | 2003-07-08 | 3M Innovative Properties Company | Method for making electrode |
KR100381920B1 (ko) * | 2001-02-16 | 2003-04-26 | 엘지전선 주식회사 | 라미네이터를 이용한 정온계수 화학 가교 공정 |
KR100378927B1 (ko) * | 2001-02-16 | 2003-04-07 | 엘지전선 주식회사 | 과전류 차단용 피티씨 폴리머 퓨즈 제조 방법 |
KR100436582B1 (ko) * | 2001-11-10 | 2004-06-19 | 엘지전선 주식회사 | 프레스를 이용한 정온계수 조성물의 화학가교 방법 |
CN102522171A (zh) * | 2011-12-31 | 2012-06-27 | 上海长园维安电子线路保护股份有限公司 | 一种圆环ptc的制造方法 |
US20170004946A1 (en) * | 2015-06-30 | 2017-01-05 | Tyco Electronics Corporation | Conductive Composite and Circuit Protection Device Including a Conductive Composite |
CN106455296A (zh) * | 2016-10-17 | 2017-02-22 | 上海长园维安电子线路保护有限公司 | 电路保护组件 |
WO2020103142A1 (en) * | 2018-11-23 | 2020-05-28 | Littelfuse Electronics (Shanghai) Co., Ltd. | Pptc composition and device having low thermal derating and low process jump |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4390489A (en) * | 1977-12-19 | 1983-06-28 | Allied Corporation | Method of shaping thermoplastic compositions on aluminum foil support |
US4237441A (en) * | 1978-12-01 | 1980-12-02 | Raychem Corporation | Low resistivity PTC compositions |
DE3280447T2 (de) * | 1981-04-02 | 1994-07-14 | Raychem Corp | Vernetzung von PTC-leitfähigen Polymeren durch Strahlung. |
JPH0690962B2 (ja) * | 1986-03-31 | 1994-11-14 | 日本メクトロン株式会社 | Ptc素子の製造法 |
US5174924A (en) * | 1990-06-04 | 1992-12-29 | Fujikura Ltd. | Ptc conductive polymer composition containing carbon black having large particle size and high dbp absorption |
JPH04247602A (ja) * | 1991-02-01 | 1992-09-03 | Fujikura Ltd | Ptcサーミスタの製造方法 |
GB2301223B (en) * | 1995-05-26 | 1999-04-21 | Johnson Electric Sa | Polymeric type positive temperature coefficient thermistors |
EP0845148B1 (de) * | 1995-08-15 | 2000-01-19 | Bourns Multifuse (Hong Kong), Ltd. | Oberflächenmontierte leitfähige bauelemente und verfahren zur herstellung derselben |
-
1997
- 1997-07-28 TW TW086110731A patent/TW343423B/zh not_active IP Right Cessation
- 1997-07-30 CN CN97198230A patent/CN1090087C/zh not_active Expired - Lifetime
- 1997-07-30 CA CA002261895A patent/CA2261895A1/en not_active Abandoned
- 1997-07-30 EP EP97934350A patent/EP0918638A1/de not_active Withdrawn
- 1997-07-30 AU AU37429/97A patent/AU3742997A/en not_active Abandoned
- 1997-07-30 JP JP10508047A patent/JP2000515448A/ja active Pending
- 1997-07-30 KR KR1019997000876A patent/KR20000029763A/ko not_active Application Discontinuation
- 1997-07-30 WO PCT/US1997/013419 patent/WO1998005503A1/en not_active Application Discontinuation
-
2001
- 2001-04-21 CN CN01117188A patent/CN1326197A/zh active Pending
Non-Patent Citations (1)
Title |
---|
See references of WO9805503A1 * |
Also Published As
Publication number | Publication date |
---|---|
KR20000029763A (ko) | 2000-05-25 |
JP2000515448A (ja) | 2000-11-21 |
TW343423B (en) | 1998-10-21 |
CA2261895A1 (en) | 1998-02-12 |
CN1326197A (zh) | 2001-12-12 |
CN1090087C (zh) | 2002-09-04 |
CN1231635A (zh) | 1999-10-13 |
AU3742997A (en) | 1998-02-25 |
WO1998005503A1 (en) | 1998-02-12 |
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