EP0399295B1 - Resistive paste able to make electrical resistive layer and resistive layer fabricated with it - Google Patents

Resistive paste able to make electrical resistive layer and resistive layer fabricated with it Download PDF

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Publication number
EP0399295B1
EP0399295B1 EP90108782A EP90108782A EP0399295B1 EP 0399295 B1 EP0399295 B1 EP 0399295B1 EP 90108782 A EP90108782 A EP 90108782A EP 90108782 A EP90108782 A EP 90108782A EP 0399295 B1 EP0399295 B1 EP 0399295B1
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Prior art keywords
resistance
paste according
resistance paste
glassy carbon
carbon
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German (de)
French (fr)
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EP0399295A3 (en
EP0399295A2 (en
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Peter Dipl.-Chem. Ambros
Walter Budig
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Preh GmbH
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Preh GmbH
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
    • H01C17/06—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base
    • H01C17/065—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base by thick film techniques, e.g. serigraphy
    • H01C17/06506—Precursor compositions therefor, e.g. pastes, inks, glass frits
    • H01C17/06513—Precursor compositions therefor, e.g. pastes, inks, glass frits characterised by the resistive component
    • H01C17/0652—Precursor compositions therefor, e.g. pastes, inks, glass frits characterised by the resistive component containing carbon or carbides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C10/00—Adjustable resistors
    • H01C10/30—Adjustable resistors the contact sliding along resistive element
    • H01C10/305—Adjustable resistors the contact sliding along resistive element consisting of a thick film
    • H01C10/306—Polymer thick film, i.e. PTF

Definitions

  • the invention relates to a resistance paste made of curable, polymeric binder suitable for the production of electrical resistance layers with at least one electrically conductive pigment dispersed therein and with solvents.
  • the invention further relates to a resistance layer made from this resistance paste.
  • a generic resistance paste is known from DE-OS 31 48 680. US Pat. No. 3,686,139 also describes such resistance pastes and, in each case, resistance layers to be produced therefrom in several examples. In order to improve the abrasion resistance of a resistance layer with regard to a contacting sliding contact, selected curable polymers are proposed as binders for these resistance pastes.
  • DE-OS 36 38 130 shows another way of increasing the abrasion resistance in resistance layers. It improves the friction properties by adding additional agents to the resistance paste.
  • Binder of the resistance paste pigment to be dispersed is known (EP-OS 0 112 975). These are hard, refractory carrier particles, for example made of aluminum oxide, which are pyrolytically carbonized from the gas phase. With such resistance layers, the contact resistance increases after the carbonization has been abraded by the sliding contact as a result of the dielectric carrier particles. Resistance layers with particles coated with pyrolytic carbon as conductive pigment are also known from DE-AS 28 12 497, additional conductive pigments, such as carbon black, graphite, nickel, etc., being additionally added to the polymeric binder if necessary.
  • the properties of polymeric resistance layers are generally to be improved if, instead of the commonly used carbons, e.g. Carbon black or graphite, a special graphite is used.
  • the proposed special graphite is produced by chlorination of carbides at higher temperatures.
  • glass-like carbon is obtained as a powder with grain sizes below 50 ⁇ m.
  • the powdery, glass-like carbon can be used as an abrasive, as a filler to increase the slip resistance of tires, or for the production of ceramic moldings.
  • the resistance to abrasion of the resistance layer is for the life of an arrangement consisting of a resistance layer and a sliding contact interacting with the resistance layer an essential feature.
  • Non-abrasion-resistant resistance layers lose substance and thereby change their electrical value.
  • Rubbed layer influences the contact ability of the sliding contact.
  • the abrasion resistance of resistance layers that can be achieved in the prior art is not yet sufficient.
  • the object is achieved in that a glass-like carbon is used as the electrically conductive pigment.
  • the object is achieved in that the resistance layer is created from one of the proposed resistance pastes.
  • the glassy carbon used according to the invention as an electrically conductive pigment has long been known (see "Zeitschrift für Werkstofftechnik", Volume 15, pp. 331-338).
  • Glassy carbon is a very special carbon with a highly disoriented, polymeric crosslink structure and with the mechanical properties of glass. Its enormous hardness, comparable to diamond, its smooth and quasi-non-porous surface and its isotropy are outstanding properties that distinguish the glassy carbon from other amorphous or crystalline materials differentiate structured carbons.
  • laboratory devices, rotors for turbochargers in automotive engineering or even tools for processing glass are produced from glassy carbon.
  • glassy carbon as an electrically conductive pigment of a resistance paste initially appears to be of little use because of the great hardness, the grain size and the poor wettability or dispersibility which were found in the test. If you overcome these concerns and the adversities in preparation and processing, e.g. by considerably increasing the conventional effort, an abrasion-resistant resistance layer is obtained from such pigmented resistance paste. After 250 hours of stress on the resistance layer due to a sliding contact frequenting 40 Hz, no disadvantageous abrasion was discernible. This corresponds to an improvement of around a factor of 100. It has been shown that conventional binders are suitable.
  • the glassy carbon Compared to the amorphous carbon as the usual conductive pigment, the glassy carbon has a smooth, non-porous surface.
  • the stability of the electrical values of the resistance layer under the influence of moisture is improved.
  • the proportion of vitreous carbon usually varies between 5 and 80 percent by weight, based on the solids content of the binder.
  • Various options can be used individually or in combination to increase the microlinearity of the resistance layer to be produced with the paste. For example, it is advantageous to choose the grain size of the glassy carbon below 50 ⁇ m. It is particularly advantageous to use rounded or spherical glassy carbon with a mixed grain size, the average value of which, however, should be less than 30 ⁇ m.
  • Other electrically conductive pigments in particular carbon black, graphite, silver, nickel, individually or in combination, can be dispersed in. For resistance areas with a lower, specific conductivity, additional pigmentation of the resistance paste with relatively high-resistance conductive pigments is recommended due to the pigment thinning.
  • the resistivity layer to be produced with the paste has a low specific conductivity, filler pigmentation with abrasion-resistant, insulating material can be recommended. This is particularly the case when the proportion of the polymeric binder on the surface of the resistance layer produced is to be small. Titanium dioxide, iron oxide, aluminum oxide, silicon oxide, talc, kaolin, barium sulfate, zinc sulfide and others are suitable as the filler pigment.
  • vitreous carbon is carbonized before it is incorporated into the binder, i.e. coated with carbon pyrolytically obtained from the gas phase, it loses its repellent properties and can be wetted and dispersed without problems.
  • the electrical resistance layer generated from the resistance paste is abrasion-resistant and increases resistance to environmental influences.
  • the finished resistance paste is made up of the following substances: 20 parts by weight of dissolved, fully etherified melamine resin 9 parts by weight of dissolved, saturated polyester resin 10 parts by weight of dissolved, modified esterimide resin 61 parts by weight of glassy carbon 3 parts by weight of an acid catalyst.
  • the roughly mixed components of the recipe are dispersed in three passes in a three-roll mill.
  • the dispersion is subsequently adjusted to the processing viscosity. This can be achieved, for example, for screen printing processing using butyl carbitol acetate.
  • the finished paste which is set for processing, is applied as a film to an electrically insulating and temperature-compatible substrate using a screen printing device.
  • the film is cured for 1 hour at 230 ° C.
  • the resistance layer according to the invention is then completed. If a different way of processing the resistance paste is considered, eg pouring, drawing, spraying, etc., the processing viscosity must be adjusted to the selected processing.
  • a further exemplary embodiment of the invention results in resistance layers which are particularly suitable as a long-life potentiometric sensor in the fuel supply of diesel-powered internal combustion engines.
  • Another embodiment leads to resistance layers, for example for elastic substrates with improved electrical homogeneity. 8 parts by weight of phenolic resin 5 parts by weight of epoxy-modified phenolic resin 5 parts by weight of epoxy resin 8.5 parts by weight of isophorones 34.5 parts by weight of glass-like carbon, splinter-shaped, grain size ⁇ 30 ⁇ m 34.5 parts by weight of glassy carbon, spherical, grain size ⁇ 20 ⁇ m 2 parts by weight of flame black 10 parts by weight of methyl ethyl ketone
  • curable resins are also suitable as modified or combined as binders for the resistance paste or layer according to the invention.
  • Typical resins from this family are, for example, alkyds, epoxies, melamines, polyacrylates, polyesters, polyimides, polyphenols, polyurethanes and others.

Abstract

The invention proposes resistive paste composed of a polymeric binder and a glassy carbon as electrically conducting pigment. A resistive layer produced with the resistive paste according to the invention is distinguished by a high abrasion resistance and improved resistance to environmental factors.

Description

Die Erfindung betrifft eine zur Erzeugung elektrischer Widerstandsschichten geeignete Widerstandspaste aus härtbarem, polymerem Bindemittel mit mindestens einem darin eindispergierten, elektrisch leitenden Pigment und mit Lösungsmitteln. Die Erfindung betrifft weiterhin eine aus dieser Widerstandspaste angefertigte Widerstandsschicht.The invention relates to a resistance paste made of curable, polymeric binder suitable for the production of electrical resistance layers with at least one electrically conductive pigment dispersed therein and with solvents. The invention further relates to a resistance layer made from this resistance paste.

Eine gattungsgemäße Widerstandspaste ist aus der DE-OS 31 48 680 bekannt. Auch die US-PS 3 686 139 beschreibt in mehreren Beispielen solche Widerstandspasten und jeweils daraus zu erzeugende Widerstandsschichten. Um die Abriebbeständigkeit einer Widerstandsschicht hinsichtlich eines kontaktierenden Schleifkontaktes zu verbessern, werden für diese Widerstandspasten ausgewählte härtbare Polymere als Bindemittel vorgeschlagen.A generic resistance paste is known from DE-OS 31 48 680. US Pat. No. 3,686,139 also describes such resistance pastes and, in each case, resistance layers to be produced therefrom in several examples. In order to improve the abrasion resistance of a resistance layer with regard to a contacting sliding contact, selected curable polymers are proposed as binders for these resistance pastes.

Einen anderen Weg zur Erhöhung der Abriebbeständigkeit bei Widerstandsschichten weist die DE-OS 36 38 130. Sie verbessert die Reibeigenschaften durch Beimengung zusätzlicher Mittel in die Widerstandspaste.DE-OS 36 38 130 shows another way of increasing the abrasion resistance in resistance layers. It improves the friction properties by adding additional agents to the resistance paste.

Um den Abrieb von Widerstandsschichten zu verringern ist weiterhin die Verwendung von Pyropolymeren als elektrisch leitendes, in das polymere Bindemittel der Widerstandspaste einzudispergierendes Pigment bekannt (EP-OS 0 112 975). Dabei handelt es sich um harte, feuerfeste Trägerpartikel, z.B. aus Aluminiumoxyd, die aus der Gasphase pyrolytisch bekohlt sind. Bei solchen Widerstandsschichten erhöht sich nach Abrieb der Bekohlung durch den Schleifkontakt infolge der dielektrischen Trägerpartikel der Kontaktwiderstand. Widerstandsschichten mit, mit pyrolytischem Kohlenstoff beschichteten Teilchen als Leitpigment sind auch aus der DE-AS 28 12 497 bekannt, wobei dem polymeren Bindemittel bedarfsweise weitere Leitpigmente, wie z.B. Ruß, Graphit, Nickel usw., zusätzlich beizumengen sind.In order to reduce the abrasion of resistance layers, the use of pyropolymers as an electrically conductive material is also necessary Binder of the resistance paste pigment to be dispersed is known (EP-OS 0 112 975). These are hard, refractory carrier particles, for example made of aluminum oxide, which are pyrolytically carbonized from the gas phase. With such resistance layers, the contact resistance increases after the carbonization has been abraded by the sliding contact as a result of the dielectric carrier particles. Resistance layers with particles coated with pyrolytic carbon as conductive pigment are also known from DE-AS 28 12 497, additional conductive pigments, such as carbon black, graphite, nickel, etc., being additionally added to the polymeric binder if necessary.

Nach der DD-PS 213 782 sind die Eigenschaften polymerer Widerstandsschichten allgemein zu verbessern, wenn als Leitpigment anstelle der gemeinhin verwendeten Kohlenstoffe, wie z.B. Ruß oder Graphit, ein Sondergraphit benutzt wird. Der vorgeschlagene Sondergraphit wird durch Chlorierung von Carbiden bei höheren Temperaturen erzeugt.According to DD-PS 213 782, the properties of polymeric resistance layers are generally to be improved if, instead of the commonly used carbons, e.g. Carbon black or graphite, a special graphite is used. The proposed special graphite is produced by chlorination of carbides at higher temperatures.

Nach dem Verfahren der DE-OS 27 18 308 erhält man glasartigen Kohlenstoff als Pulver mit Korngrößen unter 50µm. Der pulverförmige, glasartige Kohlenstoff ist gemäß den Hinweisen als Schleifmittel, als Füllstoff zur Erhöhung der Rutschfestigkeit von Reifen, oder zur Herstellung von keramischen Formkörpern verwendbar.According to the process of DE-OS 27 18 308, glass-like carbon is obtained as a powder with grain sizes below 50 μm. According to the instructions, the powdery, glass-like carbon can be used as an abrasive, as a filler to increase the slip resistance of tires, or for the production of ceramic moldings.

Für die Lebensdauer einer Anordnung, bestehend aus einer Widerstandsschicht und einem mit der Widerstandsschicht zusammenwirkenden Schleifkontakt, ist die Abriebbeständigkeit der Widerstandsschicht ein wesentliches Merkmal. Nicht abriebbeständige Widerstandsschichten verlieren an Substanz und verändern dadurch ihren elektrischen Wert. Abgeriebene Schicht beeinflußt die Kontaktfähigkeit des Schleifkontaktes. Für einige Anwendungen, vor allem auf dem Gebiet der Sensorik, ist die im Stand der Technik erzielbare Abriebbeständigkeit von Widerstandsschichten noch nicht ausreichend.The resistance to abrasion of the resistance layer is for the life of an arrangement consisting of a resistance layer and a sliding contact interacting with the resistance layer an essential feature. Non-abrasion-resistant resistance layers lose substance and thereby change their electrical value. Rubbed layer influences the contact ability of the sliding contact. For some applications, especially in the field of sensors, the abrasion resistance of resistance layers that can be achieved in the prior art is not yet sufficient.

Es ist Aufgabe der Erfindung, eine Widerstandspaste der eingangs beschriebenen Art vorzuschlagen, mit der eine elektrische Widerstandsschicht mit verbesserter Abriebbeständigkeit und mit verbesserter Stabilität gegenüber Umgebungseinflüssen herstellbar ist. Die Aufgabe ist erfindungsgemäß dadurch gelöst, daß als elektrisch leitendes Pigment ein glasartiger Kohlenstoff verwendet ist.It is an object of the invention to propose a resistance paste of the type described in the introduction with which an electrical resistance layer with improved abrasion resistance and with improved stability against environmental influences can be produced. The object is achieved in that a glass-like carbon is used as the electrically conductive pigment.

Es ist außerdem Aufgabe der Erfindung, eine Widerstandsschicht mit den genannten, verbesserten Eigenschaften vorzuschlagen. Die Aufgabe ist dadurch gelöst, daß die Widerstandsschicht aus einer der vorgeschlagenen Widerstandspasten erstellt ist.It is also an object of the invention to propose a resistance layer with the aforementioned improved properties. The object is achieved in that the resistance layer is created from one of the proposed resistance pastes.

Der erfindungsgemäß als elektrisch leitendes Pigment benutzte glasartige Kohlenstoff ist seit langem bekannt (siehe "Zeitschrift für Werkstofftechnik", Jahrgang 15, S. 331-338). Glasartiger Kohlenstoff ist ein sehr spezieller Kohlenstoff mit einer stark unorientierten, einer polymeren Vernetzung ähnlichen Knäuelstruktur und mit den mechanischen Eigenschaften von Glas. Seine enorme, mit Diamant vergleichbare Härte, seine glatte und quasi porenfreie Oberfläche und seine Isotropie sind herausragende Eigenschaften, die den glasartigen Kohlenstoff beispielsweise von sonstigen amorphen oder kristallin strukturierten Kohlenstoffen unterscheiden. Aus glasartigem Kohlenstoff werden beispielsweise Laborgeräte, Rotoren für Turbolader in der Kraftfahrzeugtechnik oder auch Werkzeuge zur Bearbeitung von Glas erzeugt.The glassy carbon used according to the invention as an electrically conductive pigment has long been known (see "Zeitschrift für Werkstofftechnik", Volume 15, pp. 331-338). Glassy carbon is a very special carbon with a highly disoriented, polymeric crosslink structure and with the mechanical properties of glass. Its enormous hardness, comparable to diamond, its smooth and quasi-non-porous surface and its isotropy are outstanding properties that distinguish the glassy carbon from other amorphous or crystalline materials differentiate structured carbons. For example, laboratory devices, rotors for turbochargers in automotive engineering or even tools for processing glass are produced from glassy carbon.

Die Verwendung von glasartigem Kohlenstoff als elektrisch leitendes Pigment einer Widerstandspaste erscheint zunächst wegen der großen Härte, der Korngröße und wegen der sich im Versuch zeigenden mangelhaften Benetzbarkeit bzw. Dispergierfähigkeit wenig nützlich. Überwindet man diese Bedenken sowie die Widrigkeiten in der Aufbereitung und Verarbeitung, z.B. durch eine erhebliche Steigerung des herkömmlichen Aufwandes, so erhält man aus einer solchermaßen pigmentierten Widerstandspaste eine abriebbeständige Widerstandsschicht. Nach einer 250 Stunden andauernden Beanspruchung der Widerstandsschicht durch einen mit 40 HZ frequentierenden Schleifkontakt war kein nachteiliger Abrieb zu erkennen. Das entspricht einer Verbesserung etwa um den Faktor 100. Es zeigte sich, daß übliche Bindemittel geeignet sind.The use of glassy carbon as an electrically conductive pigment of a resistance paste initially appears to be of little use because of the great hardness, the grain size and the poor wettability or dispersibility which were found in the test. If you overcome these concerns and the adversities in preparation and processing, e.g. by considerably increasing the conventional effort, an abrasion-resistant resistance layer is obtained from such pigmented resistance paste. After 250 hours of stress on the resistance layer due to a sliding contact frequenting 40 Hz, no disadvantageous abrasion was discernible. This corresponds to an improvement of around a factor of 100. It has been shown that conventional binders are suitable.

Gegenüber dem amorphen Kohlenstoff als übliches Leitpigment besitzt der glasartige Kohlenstoff eine glatte, porenfreie Oberfläche. Daraus mag sich die geringere Empfindlichkeit der erfindungsgemäßen Widerstandsschicht gegen Umwelteinflüsse, insbesondere Feuchtigkeit, ableiten. Die Stabilität der elektrischen Werte der Widerstandsschicht unter dem Einfluß von Feuchtigkeit ist verbessert.Compared to the amorphous carbon as the usual conductive pigment, the glassy carbon has a smooth, non-porous surface. The lower sensitivity of the resistance layer according to the invention to environmental influences, in particular moisture, may be derived from this. The stability of the electrical values of the resistance layer under the influence of moisture is improved.

Um Widerstandsschichten mit unterschiedlichem Flächenwiderstand zu erhalten, verändert man den Kohlenstoffanteil der Widerstandspaste. Üblicherweise variiert der Anteil an glasartigem Kohlenstoff zwischen 5 und 80 Gewichtsprozent, bezogen auf den Feststoffanteil des Bindemittels.In order to obtain resistance layers with different surface resistance, one changes the carbon portion of the resistance paste. The proportion of vitreous carbon usually varies between 5 and 80 percent by weight, based on the solids content of the binder.

Zur Anhebung der Mikrolinearität der mit der Paste zu erzeugenden Widerstandsschicht sind diverse Möglichkeiten einzeln oder kombiniert nutzbar. So ist es beispielsweise von Vorteil, die Korngröße des glasartigen Kohlenstoffes unter 50µm zu wählen. Ganz besonders vorteilhaft ist die Verwendung von gerundetem oder kugelförmigem glasartigem Kohlenstoff mit gemischter Korngröße, deren Durchschnittswert jedoch unter 30µm liegen sollte. Weitere elektrisch leitende Pigmente, insbesondere Ruß, Graphit, Silber, Nickel, einzeln oder kombiniert, können eindispergiert sein. Für Widerstandsflächen mit geringerer, spezifischer Leitfähigkeit bietet sich infolge der Pigmentverdünnung eine zusätzliche Pigmentierung der Widerstandspaste mit relativ hochohmigen Leitpigmenten an.Various options can be used individually or in combination to increase the microlinearity of the resistance layer to be produced with the paste. For example, it is advantageous to choose the grain size of the glassy carbon below 50 µm. It is particularly advantageous to use rounded or spherical glassy carbon with a mixed grain size, the average value of which, however, should be less than 30 μm. Other electrically conductive pigments, in particular carbon black, graphite, silver, nickel, individually or in combination, can be dispersed in. For resistance areas with a lower, specific conductivity, additional pigmentation of the resistance paste with relatively high-resistance conductive pigments is recommended due to the pigment thinning.

Bei geringer spezifischer Leitfähigkeit der mit der Paste zu erzeugenden Widerstandsschicht kann sich eine Füllpigmentierung mit abriebfestem, isolierendem Material empfehlen. Dies insbesondere dann, wenn der Anteil des polymeren Bindemittels an der Oberfläche der erzeugten Widerstandsschicht gering sein soll. Als Füllpigment eignen sich Titandioxyd, Eisenoxyd, Aluminiumoxyd, Siliziumoxyd, Talkum, Kaolin, Bariumsulfat, Zinksulfid und weitere.If the resistivity layer to be produced with the paste has a low specific conductivity, filler pigmentation with abrasion-resistant, insulating material can be recommended. This is particularly the case when the proportion of the polymeric binder on the surface of the resistance layer produced is to be small. Titanium dioxide, iron oxide, aluminum oxide, silicon oxide, talc, kaolin, barium sulfate, zinc sulfide and others are suitable as the filler pigment.

Wird der glasartige Kohlenstoff vor seiner Einarbeitung in das Bindemittel pyrolytisch bekohlt, d.h. mit aus der Gasphase pyrolytisch gewonnenem Kohlenstoff beschichtet, verliert er seine abstoßende Eigenschaft und läßt sich problemfrei benetzen und eindispergieren.If the vitreous carbon is carbonized before it is incorporated into the binder, i.e. coated with carbon pyrolytically obtained from the gas phase, it loses its repellent properties and can be wetted and dispersed without problems.

Die aus der Widerstandspaste erzeugte elektrische Widerstandsschicht ist abriebfest und erhöht resistent gegen Umgebungseinflüsse.The electrical resistance layer generated from the resistance paste is abrasion-resistant and increases resistance to environmental influences.

Nachfolgend ist ein Ausführungsbeispiel der Erfindung beschrieben. In diesem Beispiel setzt sich die fertige Widerstandspaste aus folgenden Stoffen zusammen:
20 Gewichtsanteile gelöstes, vollverethertes Melaminharz
9 Gewichtsanteile gelöstes, gesättigtes Polyesterharz
10 Gewichtsanteile gelöstes, modifiziertes Esterimidharz
61 Gewichtsanteile glasartiger Kohlenstoff
3 Gewichtsanteile eines saueren Katalysators.An exemplary embodiment of the invention is described below. In this example, the finished resistance paste is made up of the following substances:
20 parts by weight of dissolved, fully etherified melamine resin
9 parts by weight of dissolved, saturated polyester resin
10 parts by weight of dissolved, modified esterimide resin
61 parts by weight of glassy carbon
3 parts by weight of an acid catalyst.

Die grob vermischten Bestandteile der Rezeptur werden in einem Dreiwalzen-Walzenstuhl in drei Durchgängen dispergiert. Die Dispersion wird nachfolgend auf Verarbeitungsviskosität eingestellt. Dies ist beispielsweise für die Siebdruckverarbeitung anhand von Butylcarbitolacetat zu erreichen. Die fertige und für die Verarbeitung eingestellte Paste wird mittels einer Siebdruckeinrichtung auf ein elektrisch isolierendes und temperaturverträgliches Substrat als Film aufgebracht. Es erfolgt eine Aushärtung des Filmes über 1 Stunde bei 230°C. Danach ist die erfindungsgemäße Widerstandsschicht fertiggestellt. Kommt eine andere Verarbeitungsweise der Widerstandspaste in Betracht, z.B. Gießen, Ziehen, Sprühen usw., dann ist die Verarbeitungsviskosität der gewählten Verarbeitung anzugleichen.The roughly mixed components of the recipe are dispersed in three passes in a three-roll mill. The dispersion is subsequently adjusted to the processing viscosity. This can be achieved, for example, for screen printing processing using butyl carbitol acetate. The finished paste, which is set for processing, is applied as a film to an electrically insulating and temperature-compatible substrate using a screen printing device. The film is cured for 1 hour at 230 ° C. The resistance layer according to the invention is then completed. If a different way of processing the resistance paste is considered, eg pouring, drawing, spraying, etc., the processing viscosity must be adjusted to the selected processing.

Ein weiteres Ausführungsbeispiel der Erfindung ergibt im Endergebnis Widerstandsschichten, die sich insbesondere eignen als langlebiger, potentiometrischer Sensor in der Kraftstoffzufuhr von dieselbetriebenen Verbrennungsmotoren.
40 Gewichtsteile vollverethertes Melaminharz, 98%-ig
20 Gewichtsteile Polyesterharz, 50%-ig
20 Gewichtsteile gelöstes Polyamidimidharz, 44%-ig
20 Gewichtsteile Epoxyharz, 50%-ig
160 Gewichtsteile glasartiger Kohlenstoff
15 Gewichtsteile saurer KatalysatorA further exemplary embodiment of the invention results in resistance layers which are particularly suitable as a long-life potentiometric sensor in the fuel supply of diesel-powered internal combustion engines.
40 parts by weight of fully etherified melamine resin, 98%
20 parts by weight of polyester resin, 50%
20 parts by weight of dissolved polyamideimide resin, 44%
20 parts by weight of epoxy resin, 50%
160 parts by weight of glassy carbon
15 parts by weight of acid catalyst

Ein anderes Ausführungsbeispiel führt zu Widerstandsschichten, z.B. für elastische Substrate mit verbesserter elektrischer Homogenität.
8 Gewichtsteile Phenolharz
5 Gewichtsteile epoxymodifiziertes Phenolharz
5 Gewichtsteile Epoxyharz
8,5 Gewichtsteile Isophorone
34,5 Gewichtsteile glasartiger Kohlenstoff, splitterförmig, Korngröße < 30µm
34,5 Gewichtsteile glasartiger Kohlenstoff, kugelförmig, Korngröße < 20µm
2 Gewichtsteile Flamm-Ruß
10 Gewichtsteile Methyl-Aethyl-KetonAnother embodiment leads to resistance layers, for example for elastic substrates with improved electrical homogeneity.
8 parts by weight of phenolic resin
5 parts by weight of epoxy-modified phenolic resin
5 parts by weight of epoxy resin
8.5 parts by weight of isophorones
34.5 parts by weight of glass-like carbon, splinter-shaped, grain size <30 µm
34.5 parts by weight of glassy carbon, spherical, grain size <20µm
2 parts by weight of flame black
10 parts by weight of methyl ethyl ketone

Es ist anzumerken, daß grundsätzlich alle Mitglieder aus der Familie der härtbaren Harze als Bindemittel für die erfindungsgemäße Widerstandspaste bzw. -schicht auch modifiziert bzw. kombiniert geeignet sind. Typische Harze aus dieser Familie sind beispielsweise Alkyde, Epoxyde, Melamine, Polyacrylate, Polyester, Polyimide, Polyphenole, Polyurethane und weitere.It should be noted that basically all members of the family of curable resins are also suitable as modified or combined as binders for the resistance paste or layer according to the invention. Typical resins from this family are, for example, alkyds, epoxies, melamines, polyacrylates, polyesters, polyimides, polyphenols, polyurethanes and others.

Claims (8)

  1. Resistance paste suitable for the production of electrical resistance layers, consisting of hardenable polymeric bonding agents having at least one electrically conductive pigment dispersed therein, and solvents,
    characterised in that
    a glassy carbon is used as the at least one electrically conductive pigment.
  2. Resistance paste according to claim 1,
    characterised in that
    the glassy carbon content is 5 to 80% of the weight of the solid content of the bonding agent.
  3. Resistance paste according to claim 1 or 2,
    characterised in that
    the grain size of the glassy carbon is less than 50µm.
  4. Resistance paste according to claim 3,
    characterised in that
    the glassy carbon is rounded or spherical.
  5. Resistance paste according to one of claims 1 to 4,
    characterised in that
    further electrically conductive pigments, in particular carbon black, graphite, silver and nickel, are dispersed individually or in combination therein.
  6. Resistance paste according to one of claims 1 to 5,
    characterised in that
    abrasion-resistant insulating filler pigments are dispersed therein.
  7. Resistance paste according to one of claims 1 to 6,
    characterised in that
    the glassy carbon is coated with pyrolytic carbon.
  8. Resistance layer prepared from a resistance paste according to one of claims 1 to 7.
EP90108782A 1989-05-24 1990-05-10 Resistive paste able to make electrical resistive layer and resistive layer fabricated with it Expired - Lifetime EP0399295B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3916921 1989-05-24
DE3916921A DE3916921C1 (en) 1989-05-24 1989-05-24

Publications (3)

Publication Number Publication Date
EP0399295A2 EP0399295A2 (en) 1990-11-28
EP0399295A3 EP0399295A3 (en) 1991-03-20
EP0399295B1 true EP0399295B1 (en) 1994-08-31

Family

ID=6381316

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90108782A Expired - Lifetime EP0399295B1 (en) 1989-05-24 1990-05-10 Resistive paste able to make electrical resistive layer and resistive layer fabricated with it

Country Status (6)

Country Link
US (1) US5219494A (en)
EP (1) EP0399295B1 (en)
JP (1) JPH0311602A (en)
AT (1) ATE110878T1 (en)
DE (2) DE3916921C1 (en)
ES (1) ES2062159T3 (en)

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Publication number Priority date Publication date Assignee Title
DE3942799A1 (en) * 1989-12-23 1991-06-27 Bosch Gmbh Robert METHOD FOR PRODUCING AN ABRASION-RESISTANT LAYER
US5111178A (en) * 1990-06-15 1992-05-05 Bourns, Inc. Electrically conductive polymer thick film of improved wear characteristics and extended life
EP0634756B1 (en) * 1993-07-16 1998-09-30 Kabushiki Kaisha Toshiba Metal oxide resistor, power resistor, and power circuit breaker
JP3372636B2 (en) * 1994-03-16 2003-02-04 アルプス電気株式会社 Manufacturing method of resistive substrate
DE19526313C2 (en) * 1995-07-19 2000-01-27 Preh Elektro Feinmechanik Diode socket for LED with plug connection and series resistor and process for their production
DE19714561C1 (en) 1997-04-09 1998-10-22 Preh Elektro Feinmechanik Process for the production of powdery, glassy carbon, resistance paste with this carbon and use of this resistance paste as a resistance layer
DE19821529C2 (en) * 1998-05-13 2001-05-17 Peter Hille Abrasion-proof electric grinder for potentiometers and process for its manufacture
JP3587730B2 (en) * 1999-05-25 2004-11-10 アルプス電気株式会社 Resistor and variable resistor using the resistor
JP3699864B2 (en) 1999-08-02 2005-09-28 アルプス電気株式会社 Conductive resin composition and encoder switch using the same
CN1239593C (en) 2000-02-25 2006-02-01 阿尔卑斯电气株式会社 Conductive resin composition and coded switch using said composition
DE10116648B4 (en) * 2001-04-04 2006-01-26 Preh Gmbh Resistance paste and use of this resistor paste as a resistance layer
US20040113127A1 (en) * 2002-12-17 2004-06-17 Min Gary Yonggang Resistor compositions having a substantially neutral temperature coefficient of resistance and methods and compositions relating thereto
US7112755B2 (en) * 2003-05-21 2006-09-26 Nitta Corporation Pressure-sensitive sensor
CN102317376B (en) * 2009-02-16 2014-03-12 株式会社村田制作所 Conductive resin composition, process for producing electronic part using same, connecting method, connection structure, and electronic part

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US3930821A (en) * 1975-01-27 1976-01-06 Corning Glass Works Process for making carbon-containing glass resistors
US3930822A (en) * 1975-01-27 1976-01-06 Corning Glass Works Process for making carbon-containing glass resistors
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ATE21291T1 (en) * 1982-11-25 1986-08-15 Preh Elektro Feinmechanik DEVICE FOR DETECTING AN X-Y POSITION.
DE3246412A1 (en) * 1982-12-15 1984-06-20 Preh, Elektrofeinmechanische Werke Jakob Preh Nachf. Gmbh & Co, 8740 Bad Neustadt LIQUID SENSITIVE ELEMENT
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DE3477660D1 (en) * 1983-03-09 1989-05-18 Kao Corp Process for manufacturing glasslike carbon material
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JPS62112641A (en) * 1985-11-11 1987-05-23 Nitta Kk Pressure-sensitive, electrically conductive elastomer composition
DE3638130A1 (en) * 1986-11-08 1988-05-19 Preh Elektro Feinmechanik ELECTRICAL CONTROL OR RESISTANCE SPASTE
US5111178A (en) * 1990-06-15 1992-05-05 Bourns, Inc. Electrically conductive polymer thick film of improved wear characteristics and extended life

Also Published As

Publication number Publication date
EP0399295A3 (en) 1991-03-20
DE59006946D1 (en) 1994-10-06
ATE110878T1 (en) 1994-09-15
JPH0311602A (en) 1991-01-18
DE3916921C1 (en) 1990-10-11
US5219494A (en) 1993-06-15
ES2062159T3 (en) 1994-12-16
EP0399295A2 (en) 1990-11-28

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