GB2569532A - Improved positive temperature coefficient ink composition without negative temperature coefficient effect - Google Patents

Improved positive temperature coefficient ink composition without negative temperature coefficient effect Download PDF

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Publication number
GB2569532A
GB2569532A GB1720951.1A GB201720951A GB2569532A GB 2569532 A GB2569532 A GB 2569532A GB 201720951 A GB201720951 A GB 201720951A GB 2569532 A GB2569532 A GB 2569532A
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United Kingdom
Prior art keywords
semi
temperature coefficient
positive temperature
composition according
ptc
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GB1720951.1A
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GB201720951D0 (en
Inventor
Van Der Meulen Inge
Oldenzijl Rudolph
Dreezen Gunther
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Henkel AG and Co KGaA
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Henkel AG and Co KGaA
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Priority to GB1720951.1A priority Critical patent/GB2569532A/en
Publication of GB201720951D0 publication Critical patent/GB201720951D0/en
Publication of GB2569532A publication Critical patent/GB2569532A/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/52—Electrically conductive inks
    • 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
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/02—Printing inks
    • C09D11/03—Printing inks characterised by features other than the chemical nature of the binder
    • C09D11/037—Printing inks characterised by features other than the chemical nature of the binder characterised by the pigment
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/02—Printing inks
    • C09D11/10—Printing inks based on artificial resins
    • C09D11/102—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions other than those only involving unsaturated carbon-to-carbon bonds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/02—Printing inks
    • C09D11/10—Printing inks based on artificial resins
    • C09D11/106—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • 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
    • 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—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heater 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
    • 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—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heater 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—Heater 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
    • H05B3/145—Carbon only, e.g. carbon black, graphite
    • 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
    • H05B3/84—Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
    • 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
    • H05B3/84—Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
    • H05B3/845—Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields specially adapted for reflecting surfaces, e.g. bathroom - or rearview mirrors
    • 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

Abstract

The present invention relates to a positive temperature coefficient (PTC) composition comprising: a first semi-crystalline material; a second semi-crystalline material; a binder; an electronically conductive material; a compatibilizer; and a solvent, wherein melting point of said second semi-crystalline material is at least 13 °C higher than melting point of said first semi-crystalline material. Examples of semi crystalline materials include polyethylene, polypropylene, polyvinyls, nylon, polyethylene terephthalate, polybutylene, terephthalate, polyoxymethylene, natural polymers and refined hydrocarbon waxes. The composition may be formulated as an ink, an adhesive, a film, a tape or a hotmelt. The PTC formulation may be used in over-current protection devices; air conditioning units; defogging, defreezing, de-icing or snow-removal devices; heated seats, heated mirrors, heated windows, heated steering wheels; circuit protection devices, perfume dispensers or sensors. The PTC composition may comprise two semi-crystalline polymers, thermoplastic polyurethane, ethylene-vinyl acetate, conductive carbon black and butyl glycol acetate.

Description

Technical field
The present invention relates to an improved positive temperature coefficient (PTC) composition, which has elongated high resistance plateau. And therefore, the composition does not have negative temperature coefficient (NTC) effect.
Background of the invention ‘Positive Temperature Coefficient’ or ‘PTC’ materials are conductive materials characterized by a sharp increase in resistivity upon reaching a switching temperature (Ts). A function/curve of the electrical resistivity with temperature has a positive slope and within this temperature range, the electrically conducting polymeric PTC composition is said to have a positive coefficient of temperature resistance (PTCR). If the jump in resistivity is sufficiently high, the resistivity effectively blocks the current and further heating of the material such as overheating of the material is prevented. One of the main benefits of PTC materials is that no additional electronic circuits are necessary in an article that comprises a PTC material, since the PTC material itself has a characteristic similar to electronic circuits. Moreover, upon cooling, the PTC material resets itself. This jump in resistivity may often be referred to as the PTC amplitude and may be defined as the ratio of the maximum volume resistivity to the volume resistivity at room temperature (approximately 23° C).
In recent years, PTC polymer materials have been widely used for example in self-limiting heating cables and over-current protection devices. In addition, PTC materials have been utilized in self-controlled heaters. When connected to a power source, the PTC material will heat up to the trip temperature and maintain this temperature without the use of any additional electronic controllers. Furthermore, due to the extensive development, application and dissemination of electronic products, such as computers, smart phones etc. has increased the need for over-current protection devices. Compositions exhibiting PTC behavior have also been used in the electrical devices as over-current protection in electrical circuits comprising a power source and additional electrical components in series. In the electrical circuit, under normal operating conditions, the resistance of the load and the PTC device is such that relatively little current flows through the PTC device. Thus, the temperature of the device remains below the critical or trip temperature. If the load is short circuited or the circuit experiences a power surge, the current flowing through the PTC device increases greatly. At this point a large amount of power is dissipated in the PTC device. This power dissipation only occurs for a short period of time (fraction of a second). However, the temperature of the PTC device will raise to a value where the resistance of the PTC device has become so high, that the current is limited to a negligible value. The device is said to be in its tripped” state. Although, the negligible or trickle through current that flows through the circuit will not damage the electrical components which are connected in series with the PTC device. Thus, the PTC device acts as a form of a fuse, reducing the current flow through the short circuit load to a safe, low value when the PTC device is heated to its critical temperature range. Upon interrupting the current in the circuit, or removing the condition responsible for the short circuit (or power surge), the PTC device will cool down below its critical temperature to its normal operating, low resistance state. The effect is a resettable, electrical circuit protection device.
Therefore, it can be said that, the PTC inks are beneficial because of their self-regulating and fast heating properties. A less conductive PTC ink will always give a higher PTC ratio, which brings more safety, however, it will also generate less initial power (Power (W) = V2/R, higher R means less power). Typically, the resistance of a PTC material already starts to increase a little when the temperature goes up.
Various materials have been developed that show these characteristics. Among them are ceramics as well as polymer based PTC materials. There is PTC technology available, however, especially PTC inks are not that readily yet available.
In the past, industry has tried to increase the PTC ratio by using different ratios of carbon and/or graphite materials. This has provided some improvement to the physical properties and safety, however the improvements have not been sufficient.
One attempt to improve PTC technology has been to add synthesized semi-crystalline polymer, which also has a high PTC ratio into a PTC composition. Semi-crystalline polymer is providing an improvement over the existing materials. However, when the PTC compositions are overheated far beyond the PTC temperature, the resistance of the ink drops (Negative Temperature Coefficient (NTC) effect) and the material can burn through.
Therefore, there is still a need for improved PTC composition, which does not have NTC effect to increase the safety.
Short description of the figures
Figure 1 illustrates resistance curves of normal PTC ink (left) and PTC ink without NTC effect (right).
Figure 2 illustrates resistance curves of PTC composition according to the present invention and comparative composition, which shows typical NTC effect.
Figure 3 illustrates a test pattern.
Figure 4 illustrates resistance curves of compositions comprising two semi-crystalline materials having difference in melting points less than 13°C.
Figure 5 illustrates resistance curves of compositions comprising semi-crastalline material having low melting point.
Figure 6 illustrates the effect of ratio of semi-crystalline materials on PTC ration and plateau.
Figure 7 illustrates the elongation of the PTC plateau.
Summary of the invention
The present invention relates to a positive temperature coefficient composition comprising a first semi-crystalline material, a second semi-crystalline material, a binder, an electronically conductive material, a compatibilizer, and a solvent, wherein melting point of said second semicrystalline material is at least 13 °C higher than melting point of said first semi-crystalline material.
The present invention also relates to use of a positive temperature coefficient composition according to the present invention in heating elements and sensors.
The present invention further encompasses, an article comprising a positive temperature coefficient composition according to the present invention, wherein said article is selected from the group consisting of self-controlled heaters; over-current protection devices; air conditioning units; defogging, defreezing, de-icing or snow-removal devices; automotive applications selected from the group consisting of heated seats, heated mirrors, heated windows, heated steering wheels; circuit protection devices, perfume dispensers, sensors.
Detailed description of the invention
In the following passages the present invention is described in more detail. Each aspect so described may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.
In the context of the present invention, the terms used are to be construed in accordance with the following definitions, unless a context dictates otherwise.
As used herein, the singular forms “a”, “an” and “the” include both singular and plural referents unless the context clearly dictates otherwise.
The terms “comprising”, “comprises” and “comprised of” as used herein are synonymous with “including”, “includes” or “containing”, “contains”, and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps.
The recitation of numerical end points includes all numbers and fractions subsumed within the respective ranges, as well as the recited end points.
When an amount, a concentration or other values or parameters is/are expressed in form of a range, a preferable range, or a preferable upper limit value and a preferable lower limit value, it should be understood as that any ranges obtained by combining any upper limit or preferable value with any lower limit or preferable value are specifically disclosed, without considering whether the obtained ranges are clearly mentioned in the context.
All references cited in the present specification are hereby incorporated by reference in their entirety.
Unless otherwise defined, all terms used in the disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of the ordinary skill in the art to which this invention belongs to. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.
Typically, semi-crystalline polymers are being used to manufacture PTC composition. A typical PTC composition resistance versus temperature curve looks like the graph on the left hand side in figure 1. The PTC compositions have a resistance, which hardly increases with increasing temperature until an onset point has been reached, after which the resistance increases sharply. However, when the heater is used at higher temperatures, the ink will show a NTC effect, which means that the resistance will drop upon further heating. This results in overheating.
The present invention provides a positive temperature coefficient composition comprising a first semi-crystalline material, a second semi-crystalline material, a binder, an electronically conductive material, a compatibilizer, and a solvent, wherein melting point of said second semicrystalline material is at least 13 °C higher than melting point of said first semi-crystalline material. In the PTC composition, according to the present invention NTC region is absent, this is achieved by using a combination of semi-crystalline material having different PTC temperatures. This is illustrated in right hand side graph in figure 1. The absence of NTC region result in that there is no possibility to overheat the PTC composition according to the present invention.
The positive temperature coefficient composition according to the present invention comprises a first semi-crystalline material, a second semi-crystalline material, wherein melting point of said second semi-crystalline material is at least 13 °C higher than melting point of said first semi-crystalline material. First and second semi-crystalline materials can also be referred as active materials in the PTC composition.
First and second semi-crystalline materials suitable for use in the present invention are prepared by conventional means known by the skilled person.
It is preferred that the first and second semi-crystalline materials used in the present invention have a high enthalpy, and a narrow melting peak. These features are required to formulate a desired PTC composition with high PTC ratio. For example, material which has a high enthalpy, but at the same time has a broad melting peak, the resistance increases “early” and slowly, there is no rapid heating, no rapid shut down of the system and the PTC ratio is low.
Suitable, and preferred first semi-crystalline material to be used in the present invention has a melt enthalpy greater than 150 J/g, wherein the melt enthalpy is measured according to ASTM E793, preferably greater than 200 J/g.
Suitable, and preferred second semi-crystalline material to be used in the present invention has a melt enthalpy greater than 150 J/g, wherein the melt enthalpy is measured according to ASTM E793, preferably greater than 200 J/g.
Suitable first and second semi-crystalline materials to be used in the present invention have preferably narrow melt peak as determined by DSC. Preferably on- and off-set temperatures for melting should differ maximum by 50°C from the melting point, preferably by 30°C.
Furthermore, suitable semi-crystalline material to be used in the present invention has preferably a low molecular weight and narrow melting point range. Low molecular weight allows semi-crystalline material to respond faster to temperature changes.
The melting point of the second semi-crystalline material is at least 13 °C higher than the melting point of the first semi-crystalline material. The melting point difference in the first and second semi-crystalline materials enables the elongation in the high resistance plateau and result in to the absence of NTC effect.
In one preferred embodiment, the first semi-crystalline material has a degree of crystallinity of at least 5%. In another preferred embodiment, the first semi- crystalline thermoplastic material has a degree of crystallinity of at least 10%. In still another preferred embodiment, the first semi-crystalline thermoplastic material has a degree of crystallinity of at least 15%.
In one preferred embodiment, the second semi-crystalline material has a degree of crystallinity of at least 5%. In another preferred embodiment, the second semi- crystalline thermoplastic material has a degree of crystallinity of at least 10%. In still another preferred embodiment, the second semi-crystalline thermoplastic material has a degree of crystallinity of at least 15%.
Suitable first semi-crystalline material for use in the present invention is selected from the group consisting of polyethylene, polypropylene, polyvinyls, nylon, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, natural polymers, refined hydrocarbon waxes and mixtures thereof.
Preferably, hydrocarbon waxes comprise more than 95% alkane, mainly normal paraffin with straight chains and are fully saturated.
Preferably, the semi-crystalline material is selected from the group consisting of natural polymers and hydrocarbon waxes and mixtures thereof.
Suitable commercially available first semi-crystalline material for use in the present invention include, but are not limited to, Dicera 13445 and Dilavest P105 from Paramelt.
Suitable second semi-crystalline material for use in the present invention is selected from the group consisting of polyethylene, polypropylene, polyvinyls, nylon, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, natural polymers, refined hydrocarbon waxes and mixtures thereof.
Preferably, hydrocarbon waxes comprise more than 95% alkane, mainly normal paraffin with straight chains and are fully saturated.
Preferably, the semi-crystalline material is selected from the group consisting of natural polymers and hydrocarbon waxesand mixtures thereof.
Suitable commercially available second semi-crystalline material for use in the present invention include, but are not limited to, Acumist B6 and A-C-597-P from Honeywell.
A positive temperature coefficient composition according to the present invention comprises first semi-crystalline material from 0.5 to 50% by weight of the total weight of the composition, preferably from 15 to 45% and more preferably from 25 to 40%.
A positive temperature coefficient composition according to the present invention comprises second semi-crystalline material from 0.5 to 20% by weight of the total weight of the composition, preferably from 5 to 20% and more preferably from 10 to 20%.
A positive temperature coefficient composition according to the present invention comprises a binder. A binder is used to improve mechanical properties of the composition.
The suitable binder for use in the present invention is selected from the group consisting of thermoplastic polyurethanes, polyesters, polyacrylates, polysiloxanes, halogenated vinyl or vinylidene polymers, polyamide copolymers, phenoxy resins, polyethers, polyketones, polyvinyl butyral, polyvinyl pyrrolidone, polyacrylates and mixtures thereof.
The thermoplastic polyurethanes are preferred binders because they provide good adhesion and flexibility and they do not interfere with the mechanical integrity of the film.
Suitable commercially available binder material for use in the present invention include, but is not limited to, Estane 5715 from Lubrizol.
A positive temperature coefficient composition according to the present invention comprises a binder from 0.5 to 20% by weight of the total weight of the composition, preferably from 1.5 to 10% and more preferably from 2 to 4%.
A positive temperature coefficient composition according present invention comprises an electronically conductive material. Suitable electronically conductive material is for example metal powders and carbon black. Carbon black is one material that has been used in PTC materials. Carbon black is one of the most frequently used conductive fillers for polymer based PTC materials. Some of the advantages of using carbon black as compared to electronically conductive metal materials include a lower cost price and a lower density.
The preference of the electronically conductive material depends on the application. For example, if certain resistance levels are required, combination of carbon black and graphite is preferred electronically conductive material. On the other hand, for the materials which require more conductivity, the electronically conductive material, which is more conductive, like silver or metal alloys, can be used and are preferred.
The electronically conductive material for use in the positive temperature coefficient composition according to the present invention is selected from the group consisting of silver, nickel, carbon, carbon black, graphite, graphene, copper, silver coated copper, silver coated graphite, gold, platinum, aluminum, iron, zinc, cobalt, lead, tin alloys and mixtures thereof, preferably selected from carbon black, graphite and mixtures thereof.
Preferably, the electronically conductive material has a d50 particle size from 5 pm to 6.5 pm and more preferably about 5.9 pm. Preferably, the electronically conductive material has a d90 particle size from 11.5 pm to 13 pm and more preferably about 12 pm.
Preferably, the electronically conductive material has a particle surface area from 60 to 70 m2/g and more preferably about 68 m2/g.
Suitable commercially available electronically conductive material for use in the present invention include, but are not limited to, Ensaco 250G from Timcal and Vulcan XC72R from Cabot Corporation.
A positive temperature coefficient composition according to the present invention comprises the electronically conductive material from 0.5 to 15% by weight of the total weight of the composition, preferably from 2 to 12% and more preferably from 3 to 10%.
A positive temperature coefficient composition according to the present invention comprises a compatibilizer. The compatibilizer is used to adjust to rheology, in order to screenprint the PTC composition according to the present invention.
Suitable compatibilizer for use in the present invention is selected from the group consisting of ethylene-vinyl acetate copolymer, ethylene acrylic acid copolymers, ethylene vinyl alcohol copolymers, ethylene methyl acrylate copolymers, styrene butadiene copolymers, polycaprolactone polyesters, polycaprolactone and poly(tetramethylene glycol) block polyols and mixtures thereof.
Suitable commercially available compatibilizer for use in the present invention include, but are not limited to, Elwax 40W from Du Pont, Kraton G from Kraton and Struktol TPW 243 from Struktol.
A positive temperature coefficient composition according to the present invention comprise a compatibilizer from 0.5 to 20% by weight of the total weight of the composition, preferably from 0.5 to 10% and more preferably from 1 to 5%.
A positive temperature coefficient composition according present invention comprises a solvent. A wide variety of known organic solvents can be used in the present invention. Suitable solvents to be used in the present invention preferably have a flashpoint high enough to make the composition screen printable without the composition drying on the screen. Preferably the flash point of the solvent is from 70 to 120 °C.
It is also preferred that the solvents used in the present invention dissolve the binders and compatibilizers.
Suitable solvent to be used in the present invention is selected from the group consisting of alcohols, ketones, esters, glycol esters, glycol ethers, ethers and mixtures thereof. Preferably solvent is selected from butyl glycol acetate, carbitol acetate and mixtures thereof.
Suitable commercially available solvents to be used in the present invention are for example butyl glycol acetate and carbitol acetate from Eastman.
A positive temperature coefficient composition according to the present invention comprises a solvent from 0.1 to 80% by weight of the total weight of the composition, preferably from 15 to 70% and more preferably from 30 to 60%.
A positive temperature coefficient composition according to the present invention is formulated as an ink, an adhesive, a film, a tape or a hotmelt.
A positive temperature coefficient composition according to the present invention can be used in heating elements and sensors.
The present invention also encompasses an article comprising a positive temperature coefficient composition according to the present invention, wherein said article is selected from the group consisting of self-controlled heaters; over-current protection devices; air conditioning units; defogging, defreezing, de-icing or snow-removal devices; automotive applications selected from the group consisting of heated seats, heated mirrors, heated windows, heated steering wheels; circuit protection devices, perfume dispensers, sensors.
Temperature influences resistance. The graphs in figure 2 illustrate the effects of using the PTC composition according to the present invention. The solid line curve illustrates the relation between temperature and resistance for a standard PTC ink; initially almost no resistance increase, not until a certain temperature point, where the resistance increases very fast. This means rapid heating and a very quick establishment of the self-regulating temperature. At higher temperatures, the NTC region is reached and the resistance decreases again. In this region overheating will occur. The dotted line curve illustrates the same behaviour, however, the resistance does not decrease at higher temperatures above the PTC temperature. The NTC effect is absent and there is no chance of overheating.
Examples
All examples were prepared as described below.
Two pre-dissolved resin solutions were used. Estane 5715, a thermoplastic polyurethane binder which gives the mechanical properties, was first dissolved in butyl glycol acetate. A compatibilizer (Elvax 40W, Ethylene-vinyl acetate resin), being used to give the ink a better printability, was also dissolved in butyl glycol acetate. The two resin solutions were mixed together with solvent and the semi-crystalline (“active”) materials (2 or more) in a speed mixer. The material was mixed till homogeneous and subsequently the pigments were added. Then again the mixture was mixed till homogeneous and subsequently triple roll milled. If the viscosity was too high, it was adjusted by adding some more solvent.
Once the ink was ready a test pattern (Figure 3) was printed by using a silver ink and the PTC ink. Both inks were screen printed using 250 mesh stainless steel screens. A conductive silver ink was printed and dried first. The PTC ink tracks were printed on top of the silver ink and also dried.
This test pattern was used to measure the sheet resistance of the ink. Besides that, it was used to measure the resistance at different temperatures to determine the PTC curve and maximum PTC ratio.
Example 1
Exemplifies how formulations A, B and C do not have elongation of PTC plateau due to too small difference in melting temperatures of the semi-crystalline materials.
Table 1
FORMULATION A FORMULATION B FORMULATION C
20% Estane 5715 in butyl glycol acetate 23.85 23.85 23.85
10% Elvax 40W in butyl glycol acetate 19.50 19.50 19.50
Dicera 13445 0 21.49 28.65
Dilavest P105 28.65 7.16 0
Ensaco 250G 6.94 6.94 6.94
Butyl glycol acetate 21.06 21.06 21.06
The melting temperatures of the waxes used in this example have a difference of 13°C. This difference is too small to have an elongation of the PTC plateau. The graphs in figure 4 illustrates the formulas A, B and C, and the dotted line with diamonds represents formulation A. This formulation only contains the semi-crystalline material with the highest melting temperature. The solid line is formulation C, which only contains the semi-crystalline material with the lowest melting temperature. The dotted line with squares represents the blend formulation B. Not only is the PTC ratio significantly smaller for the blend than for formulation C, the plateau is not visible either.
Example 2
Formulations C and D exemplify what kind of effect has too low melting enthalpy for second semi-crystalline material.
Table 2
FORMULATION C FORMULATION D
20% Estane 5715 in butyl glycol acetate 23.85 23.85
10% Elvax 40W in butyl glycol acetate 19.50 19.50
Dicera 13445 28.65 21.49
A-C-597-P 0 7.16
Ensaco 250G 6.94 6.94
Butyl glycol acetate 21.06 21.06
In this example the second active material has a broad melting peak and a low melting enthalpy (159 J/g). Figure 5 illustrates two curves, the full line is the PTC curve of formulation C, with only one semi-crystalline material. The dotted line is the PTC curve of formulation D with two semi-crystalline materials. There is no elongation of the PTC plateau and the NTC effect is clearly visible in both curves. Furthermore, the PTC ratio of formulation D is even lower than the PTC ratio of formulation C.
Example 3
Formulations E and F exemplify influence of ratio of semi-crystalline materials on PTC ratio and plateau.
Table 3
FORMULATION E FORMULATION F
20% Estane 5715 in butyl glycol acetate 23.85 23.85
10% Elvax 40W in butyl glycol acetate 19.50 19.50
Dicera 13445 19.10 25.47
Acumist B6 9.55 3.18
Ensaco 250G 6.94 6.94
Butyl glycol acetate 21.06 21.06
The dotted line with diamonds in Figure 6 illustrates formulation C comprising only one semicrystalline material. The graph clearly illustrates that there is no visible PTC plateau. The dotted line with squares illustrates the PTC curve of formulation, E which has two semi-crystalline materials at a ratio semi-crystalline material 1/ semi-crystalline material 2 of 2. A PTC plateau can be observed; however, the PTC ratio is much lower than the PTC ratio of formulation C. The solid line illustrates the PTC curve for formulation F. Here the ratio semi-crystalline material 1/ semi-crystalline material 2 is 8 and the PTC plateau is visible. Also the PTC ratio is still maintained.
Example 4
Formulations G and H exemplify a proper elongation of the PTC plateau.
Table 4
FORMULATION G FORMULATION H
20% Estane 5715 in butyl glycol acetate 23.14 23.85
10% Elvax 40W in butyl glycol acetate 18.92 19.50
Puretemp 53 27.80 21.49
Acumist B6 0 7.16
Ensaco 250G 9.70 6.94
Butyl glycol acetate 20.44 21.06
The graphs in figure 7 illustrate resistance curves for formulations G and H. The solid line curve illustrates resistance curve of formulation G (composition comprises only one semi-crystalline material). The PTC effect is clearly visible, however no PTC plateau is present. The dotted line curve illustrates resistance curve of formulation H (composition comprises two semi-crystalline materials). The curve clearly illustrates how the PTC plateau is elongated with approximately 50°C. The PTC ratio is still relatively high (above 100).

Claims (15)

Claims
1. A positive temperature coefficient composition comprising:
a) a first semi-crystalline material;
b) a second semi-crystalline material;
c) a binder;
d) an electronically conductive material;
e) a compatibilizer; and
f) a solvent, wherein melting point of said second semi-crystalline material is at least 13 °C higher than melting point of said first semi-crystalline material.
2. A positive temperature coefficient composition according to claim 1, wherein the first semi-crystalline material is selected from the group consisting of polyethylene, polypropylene, polyvinyls, nylon, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, natural polymers, refined hydrocarbon waxes and mixtures thereof and mixtures thereof, and wherein the second semi-crystalline material is selected from the group consisting of polyethylene, polypropylene, polyvinyls, nylon, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, natural polymers, refined hydrocarbon waxes and mixtures thereof and mixtures thereof.
3. A positive temperature coefficient composition according to claim 1 or 2, wherein the first and second semi-crystalline materials have a melt enthalpy greater than 150 J/g, measured according to ASTM E793, preferably greater than 200 J/g.
4. A positive temperature coefficient composition according to any of the preceding claims 1 to 3, wherein the first semi-crystalline material is present from 0.5 to 50% by weight of the total weight of the composition, preferably from 15 to 45% and more preferably from 25 to 40%; and wherein the second semi-crystalline material is present from 0.5 to 20% by weight of the total weight of the composition, preferably from 5 to 20% and more preferably from 10 to 20%.
5. A positive temperature coefficient composition according to any of preceding claims 1 to 4, wherein the binder is selected from the group consisting of thermoplastic polyurethanes, polyesters, polyacrylates, polysiloxanes, halogenated vinyl or vinylidene polymers, polyamide copolymers, phenoxy resins, polyethers, polyketones, polyvinyl butyral, polyvinyl pyrrolidone, polyacrylates and mixtures thereof.
6. A positive temperature coefficient composition according to any of preceding claims 1 to 5, wherein the binder is present from 0.5 to 20% by weight of the total weight of the composition, preferably from 1.5 to 10% and more preferably from 2 to 4%.
7. A positive temperature coefficient composition according to any of preceding claims 1 to 6, wherein the electronically conductive material is selected from the group consisting of silver, nickel, carbon, carbon black, graphite, graphene, copper, silver coated copper, silver coated graphite, gold, platinum, aluminum, iron, zinc, cobalt, lead, tin alloys and mixtures thereof.
8. A positive temperature coefficient composition according to any of preceding claims 1 to 7, wherein the electronically conductive material is present from 0.5 to 15% by weight of the total weight of the composition, preferably from 2 to 12% and more preferably from 3 to 10%.
9. A positive temperature coefficient composition according to any of preceding claims 1 to 8, wherein the compatibilizer is selected from the group consisting of ethylene-vinyl acetate copolymer, ethylene acrylic acid copolymers, ethylene vinyl alcohol copolymers, ethylene methyl acrylate copolymers, styrene butadiene copolymers, polycaprolactone polyesters, polycaprolactone and poly(tetramethylene glycol) block polyols and mixtures thereof.
10. A positive temperature coefficient composition according to any of preceding claims 1 to 9, wherein the compatibilizer is present from 0.5 to 20% by weight of the total weight of the composition, preferably from 0.5 to 10% and more preferably from 1 to 5%.
11. A positive temperature coefficient composition according to any of preceding claims 1 to 10, wherein the solvent is selected from the group consisting of alcohols, ketones, esters, glycol esters, glycol ethers and mixtures thereof, preferably solvent is selected from butyl glycol acetate, carbitol acetate and mixtures thereof.
12. A positive temperature coefficient composition according to any of preceding claims 1 to 11, wherein the solvent is present from 0.1 to 80% by weight of the total weight of the composition, preferably from 15 to 70% and more preferably from 30 to 60%.
13. A positive temperature coefficient composition according to any of preceding claims 1 to 12, wherein said composition is formulated as an ink, an adhesive, a film, a tape or a hotmelt.
14. Use of a positive temperature coefficient composition according to any of the preceding claims 1 to 12 in heating elements and sensors.
15. An article comprising a positive temperature coefficient composition according to any of the preceding claims 1 to 12, wherein said article is selected from the group consisting of self-controlled heaters; over-current protection devices; air conditioning units; defogging, defreezing, de-icing or snow-removal devices; automotive applications selected from the group consisting of heated seats, heated mirrors, heated windows, heated steering wheels; circuit protection devices, perfume dispensers, sensors.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111269560A (en) * 2020-03-19 2020-06-12 中北大学 Nylon 6/expanded graphite/nickel composite material for electromagnetic shielding container and preparation method thereof

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11910495B2 (en) * 2019-12-13 2024-02-20 Goodrich Corporation Conductive ink with enhanced mechanical fatigue resistance
CN111647319B (en) * 2020-06-04 2022-08-05 广东康烯科技有限公司 Preparation method of PTC graphene-based conductive ink and PTC graphene-based conductive ink

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0040537A2 (en) * 1980-05-19 1981-11-25 RAYCHEM CORPORATION (a California corporation) PTC conductive polymer compositions and devices comprising them and a method of making them
JPH0636859A (en) * 1992-07-14 1994-02-10 Matsushita Electric Works Ltd Manufacture of ptc heating element
JP2007073573A (en) * 2005-09-05 2007-03-22 Matsushita Electric Ind Co Ltd Resistor
US20070187655A1 (en) * 2006-02-15 2007-08-16 Polytronics Technology Corporation Over-current protection device
EP3021331A1 (en) * 2014-11-17 2016-05-18 Henkel AG & Co. KGaA Positive temperature coefficient composition
WO2016128063A1 (en) * 2015-02-13 2016-08-18 Hewlett-Packard Indigo B.V. Ink composition with uv-curable polymeric resin
EP3106762A1 (en) * 2015-06-16 2016-12-21 Henkel AG & Co. KGaA Printed heater elements integrated in construction materials

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0040537A2 (en) * 1980-05-19 1981-11-25 RAYCHEM CORPORATION (a California corporation) PTC conductive polymer compositions and devices comprising them and a method of making them
JPH0636859A (en) * 1992-07-14 1994-02-10 Matsushita Electric Works Ltd Manufacture of ptc heating element
JP2007073573A (en) * 2005-09-05 2007-03-22 Matsushita Electric Ind Co Ltd Resistor
US20070187655A1 (en) * 2006-02-15 2007-08-16 Polytronics Technology Corporation Over-current protection device
EP3021331A1 (en) * 2014-11-17 2016-05-18 Henkel AG & Co. KGaA Positive temperature coefficient composition
WO2016128063A1 (en) * 2015-02-13 2016-08-18 Hewlett-Packard Indigo B.V. Ink composition with uv-curable polymeric resin
EP3106762A1 (en) * 2015-06-16 2016-12-21 Henkel AG & Co. KGaA Printed heater elements integrated in construction materials

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111269560A (en) * 2020-03-19 2020-06-12 中北大学 Nylon 6/expanded graphite/nickel composite material for electromagnetic shielding container and preparation method thereof
CN111269560B (en) * 2020-03-19 2022-03-29 中北大学 Nylon 6/expanded graphite/nickel composite material for electromagnetic shielding container and preparation method thereof

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