DE3302552A1 - ELECTRICALLY CONDUCTIVE ELEMENT, METHOD FOR THE PRODUCTION AND USE THEREOF - Google Patents

Description

Henkel, Pfenning, Feiler, Hänzel & Meinig

Patent attorneys

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POTTERS INDUSTRIES; INC.

KASBROUCK HEIGHTS, NEW YORK V. St. V. A.

Dr c ^h . ' G Henke ¹ Mü ^ri .c ^h e ~ DP'-irg j pt'er-r ^ g. Ber '""
Dr rer nat L Feiler. Mu "C en Dip - i ^ g VV Hanzei Wu ⁿ C" en Dip: -Phys K r '.' Some. Be ^r: -n D ^r mg A butensenone. Berim

• '.'! Ohistraße 37 3-3000 Munich SCf

"Tel. 089-982085-57 Telex 0529802ixm: d Telegrams e.lipscci

January '27, 1983 Dr. F / to US 346,648

Electrically conductive element, process
for its manufacture and use of the same

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The invention relates to flowable conductive compositions, such as molding compounds, conductive pastes, conductive paints, and electrically conductive elements made from these compositions are made to the manufacture of the electrically conductive elements from the flowable conductive compositions as well as on mica flakes, which have a conductive metal layer and are used to produce the conductive compositions mentioned above and electrically conductive elements.

Up to now, electrical pastes have consisted of silver particles, an inorganic binding component and an organic binding component has been manufactured. According to a typical example, such a paste contains 60 to 70% by weight of silver, 5 to 10% by weight of glass mass and 20 to 35% by weight of a mixture of different solvents, plasticizers and resins. This paste is applied to a substrate, for example a ceramic capacitor, whereupon the paste is fired to form a component comprising the substrate and a fired electrically conductive Body comprises, cer forms an electrically conductive connection. These components are often coated with a solder in order to be able to integrate them into a circuit later in a simple manner.

A disadvantage of these starting paste compositions and the electrically conductive bodies is that the Manufacture of the electrically conductive body to be done by heating the paste to a high temperature which can damage the substrate to which the paste is applied.

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There has been no lack of attempts to find a satisfactory substitute for the above pastes and electrically to find a guiding body. A conductive paste has been suggested that can be fired to make to form an electrically conductive body that contains microscopic glass beads coated with a precious metal are coated, such as palladium or platinum, or an alloy such as palladium, gold and Silver, and which are embedded in a matrix of a vitreous electrical material that has a melting temperature which is lower than the softening temperature of the glass beads - an electrically conductive body, which consists of palladium-coated aluminum oxide particles and silver particles embedded in a glass matrix embedded has also been suggested. The use of metals such as palladium or Gold, however, leads to a considerable manufacturing cost of the electrically conductive body and the conductive paste than its starting material. The disadvantages associated with production with high firing temperatures are also not avoided by these substitutes.

It has also been proposed to use a conductive paste containing an organic resin binder and a crushed paste electrically conductive metal-containing material, for example either silver-coated glass beads or Silver flake comprised to treat to form a conductive body. Other electrically conductive metals have also been proposed. According to another proposal, a conductive body is formed from a paste, the inorganic non-metallic silver coated particles, silver particles and an organic binder, that can be transformed into a matrix, or inorganic silver-coated non-metallic particles

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Superparticles, particles fusible to form a matrix Comprises glass material and an organic carrier. The conductive body, the silver particles and the silver coated ones inorganic non-metallic particles are in effective contact with the matrix. A An example of such a system is described in U.S. Patent Application Serial No. 187,428, filed September 15, 1980.

The object of the invention is to provide an electrically conductive element with advantageous electrical and other properties to produce with low cost compared to the typical known elements, same materials, from which it is made.

The invention provides an improved flowable conductive composition and an electrically conductive element provided. Furthermore, the Invention an improved conductive filler for converting a normally electrically non-conductive one thermoplastic or thermosetting plastic provided in an electrically conductive element.

The conductive composition and the electrically conductive element according to the invention are relatively low Costs can be produced.

The invention also provides a conductive composition, for example a molding compound provided, which is suitable for injection, pressure and / or extrusion molding without decomposition, for example a Breaking up of the conductive filler of the composition occurs.

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As a flowable conductive composition, a conductive paste or paint is provided that has a consistency suitable for screen printing or a other type of application on a substrate is suitable.

Also, a conductive paste is provided as a flowable conductive composition, which is incorporated into an electrically Conductive body can be transferred under conditions that do not have a destructive effect on the bonded substrate.

The electrically conductive element of the present invention is stable and exhibits acceptable conductivity over a long period of time during storage and operation.

Also, the present invention electrically conductive element, when it is bound to a substrate, a sufficient adhesion to the substrate ^f: ir a long time during storage and Betr_ebs on.

The invention also provides a method for producing the aforementioned electrically conductive element specified.

In addition, a mica plate is provided by the invention, which is provided with a conductive Metal, for example a noble metal / copper or nickel, is coated, and is used to produce the above mentioned flowable conductive composition and the electrically conductive element is suitable.

According to the invention, there is the flowable conductive composition essentially from a mixture of mica flakes, which are coated with a conductive metal, as well as an organic component, which is

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can be amformed into a matrix. The composition will through the metal-coated gliinmer platelets in the organic component formed. If the composition is a molding compound, it is suitable for injection molding, Compression or extrusion molding suitable for the electrically conductive element, which is shaped accordingly, for example to electromagnetic shielding, and if it is a conductive paste or paint, is these can be applied to a substrate in order to form an electrically conductive element, for example a layer or a body on the substrate. By a "flowable conductive composition" is used in accordance with the invention to understand a composition that includes conductive metal coated platelets (as well as other conductive filler materials in some embodiments of the invention) and contains the organic binder indicated above and that is flowable at room temperature and atmospheric pressure / for example a conductive paint or a conductive paste, or made flowable with the application of normally elevated temperature and / or pressure conditions can be, for example a molding compound that is flowable under the conditions that are usually used in injection molding, Compression or extrusion molding can be used.

In the case of several particularly advantageous embodiments, there is a further measure according to the invention electrically conductive element consisting essentially of mica flakes coated with a conductive metal and are embedded in a matrix made of organic material. The metal-coated mica platelets are in Real contact with the matrix.

According to the invention, an "electrically conductive element" a product with a non-flowable organic matrix in which coated with a conductive metal

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Mica flakes (and, in some embodiments, others conductive fillers) are embedded, so that the element is electrically conductive, to be understood. The element has has any suitable shape and, in numerous embodiments, either a capacitor end piece conductive center piece in a capacitor of the type used in thick film technology Element for dissipating or dissipating an electrostatic charge or an electromagnetic shield represent.

The invention also relates to a method for producing an electrically conductive element which formed a flowable composition of mica flakes coated with a conductive metal are and an organic binder, which can be transformed into a matrix, are combined and the The flowable composition is subjected to conditions which result in the organic binder in a Matrix is reshaped, in which the metal-coated mica platelets are embedded.

The invention is also directed to a product which is suitable for carrying out the invention. This product comprises a mica plate, the entire surface of which is coated with a conductive metal substantially, the metal preferably constituting at least 4% by weight of the product.

The electrically conductive elements according to the invention are characterized in that they have a volume resistivity of less than 10 ohm-cm (a specific Volume resistance of 10 ohm-cm or more is generally referred to as insulating material by experts) exhibit. For a clue, be on it

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indicated that the volume resistivity of pure silver is 10 ohm-cm. It is on it, however point out that within the range given above, the electrically conductive elements according to the invention a have volume resistivity which varies depending on the purpose of use.

The conductive paste of the present invention is therefore an intermediate product suitable for producing an electrically conductive element, in particular as a means by which the components an electrically conductive 'body or an electrically conductive coating in a simple manner on a substrate can be applied, for example a capacitor and electrical components and the like. The invention Electrically conductive bodies and coatings are in turn used to produce an electrically conductive connection or a film on a substrate. For example, the electrically conductive body can be used as end pieces Ceramic capacitors are used, for example those of the multilayer type. Such electrically conductive bodies are also suitable as central conductive elements together with light-conductive elements for example in a multilayer capacitor or a capacitor of the type in which the thick-film technology is applied.

Other output forms of the electrical according to the invention Conductive elements are used to emit or dissipate an electrostatic charge or as electromagnetic shielding usable. In the first case, the electrically conductive element serves as a medium through which the electrostatic charge at a controlled rate (depending on the volume resistivity, typically at least 10 ohm-cm), while in the latter case the element to at least a substantial extent

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reflects electromagnetic energy (the volume resistivity is typically of the order of magnitude of 1 ohm-cm).

The metal-coated glass liner according to the invention is electrical as a component of the flowable conductive composition of the invention and that of the invention conductive element suitable, namely it contributes to their or its advantageous properties and decreases generally the manufacturing costs.

The advantage of the invention is to provide a flowable conductive composition that is relatively little costs, consists of readily available materials and which are excellent for converting into an electrically conductive one Element suitable for numerous purposes. The fluidity the conductive composition is of particular advantage. The electrically conductive elements are for their part due to their adaptability: and their such performance characteristics, especially with regard to benefit from the wide range of conductivity available and their ability to adhere to substrates. A Another advantage of the invention is. That the metal coated mica flakes, preferably containing at least 4% by weight conductive metal, a suitable inexpensive one Starting material for the production of an electrically conductive element and a starting material for a flowable one represents conductive composition. Under use this coated platelet becomes a normally non-electrically conductive thermoplastic or thermoset Plastic converted into an electrically conductive element.

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Below are some preferred embodiments for illustration of the invention with reference to the accompanying drawings. Show in it

Figure 1 is a partial view of a section of the flowable conductive Composition according to the invention in an enlarged reproduction;

Figure 2 is a partial view of a section of an electrically conductive Element / which has been made from a flowable conductive composition, according to the invention in an enlarged manner Reproduction;

Figure 3 is a partial view of a section of another embodiment the flowable conductive composition according to the invention in an enlarged view;

Figure 4 is a partial view of a section of a further embodiment Form of an electrically conductive element made from a flowable conductive composition has been, according to the invention in an enlarged reproduction;

FIG. 5 shows a diagram of the specific volume resistance of various electrically conductive elements as a function the volume of conductive filler contained therein, and

FIG. 6 shows a diagram of the volume resistivity of various electrically conductive elements as a function on the percentage by weight of the conductive filler contained therein.

It should be noted that the representations in the Drawing are not to scale, but certain aspects, such as the amount of organic component, the amount of Matrix, the distances between the particles and the like are exaggerated for clarity.

In Figure 1 of the drawing is a flowable conductive composition shown, which is an organic material 10,

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for example an acrylic resin such as a Rohm & Haas B-66 acryloid resin, in which mica flakes 12 are suspended with a silver coating 14. The silver coating 14 on a mica wafer 12 makes up, for example, 20 to 70% by weight of the wafer and the coating the end.

This silver coating is supposed to be on a mica plate also illustrate a silver-coated mica platelet that contains at least 4% by weight, preferably at least Has 12 wt .-% silver. In a typical example, the conductive composition is on a suitable substrate applied.

In Figure 2, an electrically conductive element is shown, which is a matrix of an organic material 42, which at This embodiment comprises a cured acrylic resin, in this case a Rohm & Haas B-66 acryloid resin in which Mica flakes 20 are embedded with a silver coating 22. The electrically conductive element is in a typical example applied to and adhered to substrate 44. The silver layer 22 on a mica plate For example, 20 makes up 20 to 70% of the weight of the die and coating. Adjacent silver-coated Mica platelets touch each other with their surfaces at points 2 4 or are sufficiently located in one small distance from each other at points 26, 28, 30 and 32 that an electron transfer between them take place can. It should be noted that the platelets overlap, creating an advantageously large conductive area is formed. At the point 34 the coated plate represents part of the surface of the electrical Conductive element. Likewise, for example, at points 36, 38 and 40 are those coated with silver Mica platelets sufficiently close to the surface of the

electrically conductive element or substrate 4 4 to a Allow electron transfer between the surface and the silver-coated platelets. In this way Conductive paths are formed by the electrically conductive element.

Other embodiments of a flowable conductive composition according to the invention also contain particles of a conductive metal and / or inorganic non-conductive ones Particles coated with the same. In Figure 3 is one embodiment of the conductive composition shown in which both are present. The composition comprises an organic binder 50, the in this embodiment an acrylic resin, in turn Rohm & Haas B-66 a ryloid resin in which mica flakes with a gold coating 54 are suspended, aluminum grains 56 with a gold coating 58 and pure gold particles in the form of platelets 60. The gold coatings 54 and 58 on the mica platelets 52 and the aluminum granules 56, for example, make up 20 to 70% the total weight of the coated chip and the coated granule. The composition contains also soot particles 62. In a typical example, the conductive paste is applied to a suitable substrate 63.

In Figure 4, an electrically conductive body is shown, which is a matrix of an organic material 108, the in this embodiment contains a hardened acrylic resin, for example a Rohm & Haas B-66 acryloid resin, in which mica platelets 64 are embedded with a gold coating 66, aluminum granules 6 8 with a gold coating 70 and pure gold particles in the form of platelets 72. The incorporation of gold (or other conductive Metal) particles of a different shape are also within the scope of the invention. However, platelets are out

pure material is particularly advantageous. The electrically conductive element may also contain carbon black particles 73. In In a typical example, the electrically conductive body is in turn applied to a substrate 106 and adheres to it. For example, gold coatings 66 and 70 on mica flakes 64 and aluminum granules 68, respectively 2 from 0 to 70 percent of the total weight of the coated flake and the coated granule. Neighbors gold-coated mica flakes are in contact or close across their surfaces at location 69 located enough at location 71 that electron transfer can take place between them. The same applies to neighboring gold-coated aluminum grains at positions 74 and 76 as well as to neighboring gold plates at positions 78 and 80, respectively. There are also an adjacent gold-coated mica plate and a gold-coated aluminum grain in direct surface contact at point 82, a gold-coated one Aluminum grains and a gold plate at the point and a gold-coated mica plate and a pure one Gold platelets at position 86. (It will be understood that, compared to the overlap of metal-coated platelets, the the conductivity of the electrically conductive element increases considerably, the coated granules only create a tangential or punctiform contact and are therefore less of an advantage.) At the Position 88 a gold-coated plate and a gold-coated grain are sufficiently close to one another, to enable electron transfer. This condition exists between a gold-coated plate and the pure gold flakes at 90 and between a gold-coated granule and one pure gold platelets at point 92. At points

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91 and 93 represent the gold-coated mica platelets a part of the surface of the element. In addition, at points 94, 96 and 98, for example gold-coated mica plate and a gold-coated one Aluminum grains or gold flakes are sufficiently close to the surface of the electrically conductive body, to allow electron transfer between them and the surface. At positions 100, 102 or 104, a gold particle, a gold-coated mica plate, and a gold-coated granule are sufficient placed near atn substrate to an electron junction to allow in between. So there are conductive tracks formed by the electrically conductive element.

The representations of FIGS. 1 to 4 serve to illustrate other electrically conductive elements and conductive ones Starting compositions, such as electromagnetic shielding articles and starting molding compounds. It understands that in most cases such objects and molding compositions are not bound to a substrate and above also have a thickness on the order of about 3.2 mm (1/8 inch) (while those shown in FIGS layers shown are typically around 30μ thick). Otherwise, Figures 1 to 4 represent exactly one above mentioned shielding article and a starting composition represent.

The conductive metal, which is incorporated in a flowable conductive composition according to the invention, is As the name suggests, a conductive component in an electrically conductive element is ultimately made from the conductive composition. The length and shape of the conductive metal in the composition are therefore largely owned by the

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Shafts of such an electrically conductive element dependent.

The conductive metal is advantageously copper or nickel, or silver, GoID ₇ palladium, platinum or any other precious metal. In some embodiments, silver, gold, and / or copper are preferred because of their advantageous conductivity and / or relatively low cost. While the deposition of metal pigments such as titanium dioxide and iron oxides on mica for coloring is known, mica platelets coated with a conductive metal have so far not been used for electrical conduction.

The coating of the conductive metal on the mica flakes of the flowable conductive composition represents a layer covering substantially the entire surface of each of these platelets. Preferably If this layer has a uniform thickness, however, the thickness at the individual points of the platelet surface also be different without thereby departing from the invention. The layer of conductive metal only needs to be of sufficient thickness to ensure the conductivity (to the desired extent) of the electrical To ensure conductive element made from the conductive composition of the present invention. However For example, the thickness of the layer can be increased from a minimum to the extent that a cost analysis allows. Typically the thickness of the layer of conductive metal is at least 0.01μ.

According to the invention, the metal-coated mica platelet consists of at least 4 up to 70% by weight of the conductive Metal coating. Preferably with

a conductive metal coated mica flakes at least 12, in particular at least 16% by weight metal coating.

The incorporation of the metal-coated platelets into the flowable conductive composition ensures a good conductivity of an electrically conductive element made from it without any noticeable impairment of it electrical or other properties. It is understood that this embodiment through the use of a conductive metal coated mica flakes as opposed to using a pure metal (such as silver) alone also has cost advantages.

The amount of the conductive metal that according to the invention in incorporated into the electrically conductive member is 2 to 90% by weight. Depending on the amount of organic Binders and other materials contained in the flowable composition and from the Function of the electrically conductive element (a parameter that easily determinable by one skilled in the art), is the amount of conductive metal contained in the flowable conductive Initial composition is included, up to 90%, but typically at most 15%.

The conductive metal coating, when deposited on a mica wafer, generally conforms to the contours of the platelet, so that the shape of the metal-coated platelets generally corresponds to the shape of the uncoated Plate corresponds. Including the metal layer, the coated platelets are one size on, which allows the desired properties of the to obtain flowable conductive composition and the electrically conductive member according to the invention.

I. E. the metal-coated platelets have, for example, a size so that they can be incorporated into the flowable conductive composition their fluidity not noticeably impaired when applied to a substrate or when injection, compression or extrusion molding, as required. The metal-coated platelets typically have a size with regard to their maximum dimension from 0.1 to 200, preferably 0.5 to 44 μ.

Corresponding to the above, the metal-coated Platelets are preferably formed by silver-coated mica flakes. The ones coated with silver Platelets, including the silver layer, again typically preferably have a size of 0.5 to 44 fx in their largest dimension. More examples of silver-coated Mica flakes with a suitable size are those with a size of 44 to 74 U and 74 to 200 ^ -

The mica platelets can in turn consist of natural or synthetic mica. Mica belongs to the group of layered silicates. The structure of mica is treated quite extensively in the literature, for example by L. Pauling in Proc. Nat'l. Acad. Sci., 16, 123 (1930); by WW Jackson and J. WestZ. Krist., 76, 211 (1930) and by JW McCauley, RE Newnham and GV Gibbs, Am. Mineral., 58, 249 (1973). Although they vary somewhat in their chemical composition, all mica contain hydroxyl and / or fluoride radicals, a silicate or germate group and an alkali and an alkaline earth component. Examples are biotite, muscovite, phlogopite, lepidolite, fluorophlogopite, barium disilicate and lead disilicate. Typically, mica has the following properties: specific gravity 2.6 to 3.2; Mohs hardness 2.8 3.2; Refractive index 1.56 - 1.60; Dielectric constant 6.5 - 8.7; non-flammable; heat resistant up to about 600 ⁰ C.

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Natural mica comes in the United States, Canada, Madagascar, India, South Africa and South America. Synthetic mica is named after any known or Common processes produced, for example by electrothermal Growing a single crystal. An interesting example of a synthetic mica is fluorophlogopite (i.e., a fluorine derivative of phlogopite) produced, for example, by a process in which the Starting materials / comprising potassium silicon fluoride, aluminum oxide, silicon oxide, potassium feldspar and magnesium, melted in a resistance furnace, whereupon the melt slowly cooled to crystallization temperature is used to form synthetic mica crystals. This Product has a higher heat resistance than natural mica, whereby its dielectric properties and its processability are the same.

The mica group is characterized by its excellent cleavability. They can therefore be very thin flexible panels are split. This property requires control of the thickness of the mica that is applied will. The cleavage is expediently carried out by grinding the mica, but others are also possible common or known methods can be used. In this way, mica flakes of the desired thickness can be used Implementation of the invention can be obtained. The aspect ratio of these platelets is generally greater than 20th

The coating of the mica platelets with a conductive Metal is conveniently carried out by one of the numerous known methods. For example, the Silver plating by fluidization using dry or wet methods, by electroless plating and the like

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the same can be applied (see, for example, US Pat. No. 3,635,824).

The flowable conductive composition, such as a paste or a molding compound which contains mica flakes coated with a conductive metal is advantageous because it has favorable flow and distribution properties. I. E. the paste or molding composition according to the invention has a sufficient flowability so that it is easily applied to substrates and suitable for injection molding suitable without excessive resistance and the like occurring. When done conventional procedures then the conductive composition is also such that the distribution of those coated with metal The platelet is fairly uniform after application, which in places changes the properties of a electrically conductive element made from the flowable conductive composition to a minimum be reduced. Furthermore, the glinmer platelets are quite resistant to breakage; H. against breaking apart into smaller particles during their processing, such as injection molding, pressing and molding Extrusion forms.

Due to the above-mentioned overlap instead of a point contact of those coated with a conductive metal Mica flakes and their large surface area is the total amount of metal-coated flakes in an electrically conductive element made from the flowable conductive composition of the present invention is, typically only about 20% by volume. This amount of electrically conductive element is acceptable in some embodiments even down to 5% by volume, based on the cured element. Achieved in other embodiments however, it is expediently 90% by volume, preferably

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50% by volume, in particular 40% by volume. In dependence of the amount of organic binder and other materials present in the flowable conductive composition are contained and survive the formation of the electrically conductive element, the amount of the metal-coated Platelets that are in the starting conductive composition is included, up to 90% by volume, typically about 30% by volume or less.

While a conductive composition, the metal-coated Containing mica flakes, is of great advantage, are in some embodiments of the invention in the conductive paste also includes inorganic, non-metallic particles coated with a conductive metal, conductive Metal particles / fibers coated with a conductive metal or combinations of two or contain more of the same.

The coating of the conductive metal on inorganic non-metallic particles or a fibrous material provides also represents a layer covering substantially the entire surface of each of these particles or fibers. Again, it is preferred that this layer be of uniform thickness, but the thickness can vary from place to place Vary location of the particle or fiber surface without departing from the invention. The layer of the conductive Metal need only be of sufficient thickness to have conductivity (to the extent desired) in the ensure electrically conductive element. However, the layer thickness can be increased beyond this minimum, z. B. to the extent that it allows a cost analysis. The thickness of the layer of conductive metal is up to 10% of the smallest dimension of the inorganic non-metallic Particles and / or up to 10% of the diameter

of the fiber material. It should be noted that even if a different material than with as the conductive filler material a conductive metal coated mica flakes in the electrically conductive element and the flowable conductive one The initial composition is contained, the total volume loading of the element is generally between 5 and 90%, is preferably 5 to 50%. So if the element and its initial conductive composition with a conductive Metal coated inorganic non-metallic particles and / or fibers in addition to those with a conductive metal contains coated mica flakes, the volume loading of the element and the starting composition is reduced with the coated mica platelets accordingly. Since the total weight load of the element with the conductive metal is generally in the range between 2 and 90%, even if another conductive filler is used than mica flakes coated with a conductive metal is included, the weight loading of the element and the Starting composition with the metal of the coated Mica platelets reduced accordingly. It should be noted that with the aforementioned metal-coated inorganic non-metallic particles and metal-coated fibers make up 4 to 70% of the metal coating Total weight.

As for the above-mentioned inorganic non-metallic particles coated with a conductive metal, thus they contain at least 8, preferably at least 12% by weight of metal coating. Likewise, in particular Gold or copper preferred as the metal. In some embodiments, the incorporation of these metal-coated supports Particles help provide good rheological properties to the flowable conductive composition as well as good conductivity of what is finally formed

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electrically conductive element is achieved and maintained without a noticeable impairment of their or its electrical or physical properties, such as the adhesion occurs. It is understood that these embodiments also bring cost advantages through the use of the coated with a conductive metal inorganic non-metallic particles as opposed to the use of a conductive metal alone. It is also within the scope of the invention, a flowable conductive composition with a conductive metal to incorporate coated inorganic non-metallic particles containing up to 60% by weight of metal coating have, for example from 25 to 60 wt .-%. Metal-coated particles that contain slightly less than 25% by weight, are suitable in some advantageous embodiments. In some other particularly preferred embodiments the metal-coated particles contain 4 to 16% by weight of metal coating. Examples are Particles containing about 4, 8, 12 and 16 percent by weight metal coating.

In turn, the inorganic non-metallic particles have a suitable irregular shape or instead a substantially regular shape. These particles are, for example, grains, spheres or spheroids. Since the conductive metal coating essentially conforms to the contour of the particle, the coated Particles have a shape that corresponds to the shape of the uncoated particle. The coated particles have a size that allows the desired properties of the conductive paste and the electrically conductive Body is achieved according to the invention, as it or he is described above and below. the Size of the maximum dimension of the metal-coated

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-, 29 particles is typically 1 to 200 μ on average.

The inorganic non-metallic particles suitably exist from one of many materials that have properties and physical parameters that allow that the objects of the invention are achieved. In this connection it should be pointed out that "Nonmetallic" refers to the properties and physical data of these materials, and the presence of metal atoms or ions does not exclude as long as "Non-metallic" properties and physical data are available. Suitable materials typically have non-electrically conductive properties. Accordingly, these materials are typically glasses, ceramic Substances and naturally occurring mineral substances. Other examples of suitable materials are as follows: Oxides such as bauxite, corundum, ilmenite, brookite, anatase, rutile and magnetite, and hydroxides such as brucite; Sulfides such as galena, pyrite, calcopyride and sphalerite; Halides, such as Sodium chloride, SyIvit and fluorite; Carbonates, such as calcite, magnesite and siderite, "nitrates, such as sodium nitrate / and Borates such as borax and kernite; Sulfates, chronates and molybdates, examples being celestite, anhydrite and gypsum; and phosphates such as bivianite, apatite and pyromorphite, * arsenates such as erythritol / and vanadates, such as bavanadite. Further examples of suitable materials are expediently shown in the following Categories: tectosilicates, including the silica group, the feldspar group, the feldspathoid group, the zeolite group; various philosilicates including kaolinite, soapstone and vermiculite, inosilicates including the amphibole group, for example the cummingtonite series, the proxy group, including the hypersthene series, for example spodumene, as well as the pyroxenoid group, cyclosilicates including beryl and tourmaline, the

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Sorosilicate group, for example Idocrase; the neosilicates, including the Olvin series, such as magnesium iron silicate, as well as including willemite, the aluminum silicate group, the Garnet group, and the silicates of indeterminable structure, such as prehnite, chrysocolla and dumortierite. It is understood that both synthetic and naturally occurring inorganic non-metallic materials are suitable for carrying out the invention.

The composition of the inorganic non-metallic particles must generally be chosen so that the Particles under the processing conditions to which the flowable conductive composition of the present invention undergoes is subject to the production of an electrically conductive element, does not soften or noticeably deform.

The particles of inorganic non-metallic material are made in any known or known manner Way made.

As with the coated mica particles mentioned above becomes the conductive metal coating of the inorganic non-metallic particles by any of a number of known methods. For example The silver plating is done by fluidization with dry or wet methods, by electroless plating or the like (see U.S. Patent 3,635,824 mentioned above).

The incorporation of conductive metal coated inorganic non-metallic particles such as spherical ones or spheroid particles, may be advantageous in those embodiments in which the increased flowability and distribution properties are particularly desirable

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because the coated particles can be tailored to that they are particularly useful in imparting these properties to a flowable conductive composition. It is also possible to measure the conductivity of an electrically conductive element, based on a certain silver content, by incorporating such spherical particles coated with a conductive metal. However, it should be noted that the amount of so coated spherical incorporated particles should be closely controlled. That means, despite the notice, that certain conductive bodies which only contain silver-coated spheres as conductive filler, based on a certain silver content, have a greater conductivity than a conductive element that contains only silver-coated mica particles, the first-mentioned conductive body forms a system that leads to rigid is for a suitable application in the manufacture of membrane switches. If it's made of a coated Material containing balls is made, the material that forms the button of the switch is too stiff, to be deformed so that no contact with the associated component of the switch is state-of-the-art. An inventive conductive element, however, enables a system that is sufficiently flexible and yet a has significantly greater conductivity than a system that only contains pure silver as a filler.

As stated above, in some embodiments of the present invention, the flowable conductive composition includes also fibers coated with a conductive metal, either in conjunction with a conductive one Metal-coated mica flakes alone or inorganic non-metallic ones coated with a conductive metal Particle. The incorporation of such

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layered fibers leads to considerable in some directions Advantages. For example, a filler is thereby present in the conductive element which has a large aspect ratio and has a large surface area. However, this incorporation also leads to certain disadvantages. As above mentioned, these fibers can break, thereby reducing the properties of an electrically conductive element change, furthermore they lead at best to a linear contact with the other fillers, whereby the Conductivity is potentially reduced. The invention can effectively reduce these disadvantages. The incorporation of conductive metal coated mica flakes along with these coated Fibers increases conductivity because the coated platelets create a sheet-like overlap instead of one lead to bare lenticular contact. An improved conductivity is thus achieved. Also are the coated ones Platelets more resistant to breakage than the appropriately coated fibers. The invention thus provides conductive, coated fiber-containing, flowable compositions and electrical conductive elements for certain applications improved in a very advantageous manner.

Fibers coated with a conductive metal useful in practicing the invention are commercially available and well known.

As with the mica flakes, the conductive metal layer adapts when deposited on the fiber, it generally follows the fiber contours, so that the shape of the coated Fiber corresponds to the shape of the uncoated fiber. It should be noted that these coated Fibers are of a size and shape that permit

3H

that the desired properties of the flowable conductive composition and the electrically conductive element after of the invention can be achieved, for example, the simple application of the composition to a substrate or its Flowability in injection, pressure and extrusion molding not significantly affect.

The fibers expediently consist of one of the numerous Materials having properties and physical parameters consistent with the objectives of the invention. Such materials are typically glasses such as fiberglass, ceramic substances and of course occurring mineral substances. Examples of suitable materials are the following: glass, asbestos, amphibole and Wollastonite. It is understood that both synthetic and naturally occurring inorganic materials can be used to carry out of the invention are suitable. Various metals such as aluminum, copper and nickel are also suitable. the Coating of the fibers with a conductive metal is expediently carried out according to a known method, as discussed above.

As stated above, in various embodiments of the invention, a portion of the conductive metal, such as Gold, platinum ^ palladium or copper, the flowable conductive composition as particles of essentially incorporated into pure metal. The coating metal is preferred the same as that of which the particles are made, the particles being in the form of platelets. Particles which have a different shape, however, are also within the scope of the invention. Especially in those In cases where the conductive metal coating is a relatively small amount, the particles typically constitute 0.5 to 4 0 wt .-% of the flowable conductive composite

33Ö2552

- Fig. In some embodiments, the Particles constitute at least 10% by weight of the paste.

In some embodiments of the invention, the conductive Metal particles formed by a composite of more than one metal in which a core of one other metal or metals coated with a conductive metal. Suitable conductive metal particles are for example iron coated with copper or with a noble metal such as silver or gold. The whole particle its outer layer or core is sometimes formed by an alloy. Brass and rustproof Steel are examples, but other conventional alloys can also be used, for example those of gold, platinum, palladium and / or copper. In some embodiments of the invention, the use brings such conductive metal particles entail cost savings as a large portion of the conductive Metal is replaced by a more accessible and / or less expensive core.

The total amount of conductive metal incorporated into the flowable conductive composition is at least 2% by weight of the composition. This amount of conductive metal is in the form of a coating or in the form of coatings on the mica flakes (and, if present, the inorganic non-metallic particles and fibers) as well as conductive metal particles, if any, incorporated. In some execution forms expediently more than one elemental metal and / or alloy incorporated in order to form the total amount. Preferably enough conductive metal is incorporated into the composition by at least 5%, especially at least Make up 10% of the weight of the composition.

'33 Ü2552

In some embodiments of the invention, there is conductive filler in the flowable conductive composition other than those coated with a conductive metal Mica flakes and optionally one or more of those described in the preceding paragraphs other conductive fillers made from carbon black particles. The soot does not need to be specially treated and can for example, can be used immediately as it is produced "in the oven". It's practically any type of soot suitable as long as the size of the particles does not interfere with the desired flowability of the conductive composition. The largest dimension of suitable particles is typically 20 to 30 μ. Examples of suitable ones Carbon blacks are those that come under the description of the goods Ketjen Black EC, Vulcan XC-72 and Acethylen-Schwärζ sold will.

The flowable conductive composition also contains an organic binder that makes up the matrix organic material of an electrically conductive element made from the composition is formed. The organic binder expediently contains an inert organic material or materials that are too a matrix are deformable. The binder gives the composition the appropriate flowability, for example a suitable consistency for application to a substrate by screen printing, painting (e.g. electrostatic or with a brush), dipping (after loading a rack), continuous machine dipping and the like or for injection, printing or extrusion forin work.

In many embodiments, the includes organic Binder one or more resins and one or more solvents to give the conductive composition the

33Ü2552

To give the desired consistency, however, in some embodiments, for example in the case of molding compositions, the organic binder is typically solvent-free. Examples of suitable substances are low molecular weight aliphatic unsaturated organic polymers or a mixture of an aliphatic unsaturated organic polymer and a copolymerizable aliphatic unsaturated organic monomer such as styrene. These substances comprise for example at 25 ⁰ C a viscosity of about 5 to 1000 cPa · ^s. Examples of suitable organic binders include those embodiments of the invention relating to a "molding compound", particularly polypropylene, polystyrene, high density polyethylene, polyvinyl chloride and nylon. Further examples are: low molecular weight polyimides which contain unsaturated acrylic amides, as described, for example, in US Pat. No. 3,535,148, low molecular weight polyesters which contain unsaturated acrylic groups, as described for example in US Pat as described, for example, in US Pat. No. 3,551,246 and US Pat. No. 3,551,235, acrylic acid esters and methacrylic acid esters of silicone resins; Melamine, epoxy resins, allyl ethers of polyhydric alcohols; Alyl ethers of polybasic aliphatic and aromatic acids, low molecular weight maleimide-substituted aromatic compounds; Cinnamic acid esters of polyhydric alcohols; Mixtures of one or more of the above components and the like. Other examples are unsaturated polymers such as polyesters of glycols and c * -, / £ unsaturated dicarboxylic acids such as maleic and fumaric acid, are no unsaturation either with or without other dicarboxylic acids which inoi- _r (I-position, for example phthalic acid, isophthalic acid and Succinic acid, dissolved in a copolymerizable aliphatic unsaturated solvent such as styrene.

benzene. Methyl methacrylate or mixtures of such solvents as described in US Pat. No. 2,673,151 and US Pat. No. 3,326,710. Further examples are unsaturated organosiloxanes having 5 to 18 silicon atoms and such siloxanes in combination with an organic vinyl monomer. The organic binder is, for example, an acrylic resin or an epoxy resin. Examples of suitable acrylic resins are methacrylic polymers. Examples of suitable epoxy resins are irqendein monomeric, dimeric, or polymeric epoxy material oliqomeres having one or more functional Spoxygruppen, for example, bisphenol-A and Diglycyläther. In a particularly preferred embodiment, the organic binder is an acryloid resin, ie a synthetic acrylic acid ester polymer.

Suitable solvents are coal tar hydrocarbons, chlorinated hydrocarbons, ketones, esters, ether alcohols and ether esters. Examples are xylene, toluene, Methyl ethyl ketone and alcohols, such as aliphatic alcohols, with up to 20 carbon atoms, for example ethanol and propanol. The organic binder can also contain several customary additives, for example catalysts or substances which sensitize the binder to irradiation, for example with ultraviolet light. The sensitizers are e.g. B. conveniently incorporated in small amounts, for example 0.5 to 5% by weight of the binder. Examples are ketones such as benzophenone, acetophenone and the like, Benzoins and substituted benzoins, thioureas and aromatic disulfides. Examples are also azides, Thioketones and mixtures thereof. The binder is incorporated into the paste in an amount suitable to to obtain the desired flowability or rheology discussed above, for example in an amount of 35 to 40% of the weight of the paste, but sometimes

only 15% and in some cases even only 5 to 10% of the weight of the paste.

The flowable conductive composition is prepared, for example, by using a conductive metal coated Glirranerolättchen as well as with a conductive metal coated anoroanische non-metallic particles with a conductive metal-coated fibers, conductive metal particles and / or carbon black, in some embodiments, and an organic binder in a matrix is transferable, to be united. If conductive metal particles are incorporated into the conductive paste, they can be wetted in a three-roll mill, for example, in admixture with an organic binder. The coated mica flakes can be incorporated together with the coated inorganic non-metallic particles, fibers and / or carbon black (if used) and suitably mixed into the organic binder (or such a binder containing conductive metal particles) in a suitable device, e.g. SPEX mixer or a conventional paint shaker. When forming a molding compound containing such conductive metal particles, these particles are put in a compounder for mixing together with an organic binder and mica flakes coated with a conductive metal. The resulting flowable conductive composition is then molded as such into the desired shape or on a! Substrate applied, for example a capacitor or a resistor or another dielectric component, etc., in connection with the production of a further circuit component, or it is packaged, stored and sent for further use.

According to the invention, an electrically conductive element is derived from a flowable conductive composition

HO -ab

made by subjecting the compositions to conditions that are sufficient to transfer the binder into a matrix in which the metal-coated Platelets, etc. are embedded. During the formation of the matrix, any solvent component that is in the organic component is present, largely, preferably completely removed.

Typical methods and conditions for forming the matrix from the organic binder are: drying the flowable conductive compound at room or elevated temperature in air; Heating the composition to a temperature of about 350 ⁰ C during a period of time sufficient for matrix formation; Ultraviolet exposure of the composition; catalyzed curing of the composition at a temperature in a range suitable for use of the selected catalyst. Other commonly used methods for reshaping the organic binder into a matrix, for example curing, are also suitable. The matrix formed is an organic material made by a suitable molding process and / or conditions. The organic matrix is thus expediently a material which is formed from a resin or resins described above in the organic binder, which resin or resins polymerize, crosslink or undergo a similar change in order to form the matrix. It will be understood that the method and conditions selected to form the matrix will depend on the type of organic binder employed, and that this method and conditions are intended to result in the formation of a suitable matrix without interfering with a conductive one Metal-coated mica flakes or one of the other fillers present deform or the components of the system change in other ways, so that the

MA

- <3tJ-

Performance, especially the conductivity of the electrically conductive element is impaired.

In those embodiments of the invention, at which the flowable conductive composition is a conductive paste, paint or the like that is suitable for application is suitable on a substrate, for example a ceramic multilayer capacitor, it is within the limits of the invention to form an electrically conductive body from the paste, etc. directly on a substrate that the paste has been applied. For example, a paste is applied to a substrate and in a suitable manner Air-dried, heated, irradiated, catalytically cured or heated together with the substrate, to which she is upset. It goes without saying that the conditions for the formation of the electrically conductive body directly on the substrate are the same as those discussed above for this formation, with additional It should be noted that the manufacturing methods or conditions of the substrate or those with a conductive Metal-coated mica flakes, inorganic non-metallic particles or fibers, and conductive ones Should not damage metal particles. The conductive paste, etc. of the present invention is typically applied to a Substrate applied, which has been made of an insulating material, to an electrical circuit thereon to form, or on a capacitor as "AbschluBoaste" or it is sandwiched around a dielectric Material applied to form conductive end or center pieces of various capacitor components. The application is carried out by any known or common method such as screen printing, application with a squeegee or "spraying." This way, capacitors of the appropriate size, often called "chips"

πα

labeled, preserved, packaged for later use, encapsulated in a hermetic Glass packing (which in turn generally has to be heated) or immersed in an organic system into a solder to form components that can easily be integrated into circuits in the desired manner or for connection (usually by dipping in a solder).

In other embodiments, such as manufacturing electromagnetic shielding, the flowable conductive composition is carried through the molding compound and converted into a separate integrated body, if desired by injection molding, pressing or Extrusion molding or the like formed. the Molding aspects are the same as mentioned above, except that there is no substrate is available. The aforementioned significant advantage of incorporating coated platelets over fibers or coated fibers in the paste is mainly realized in these embodiments. The platelets are more resistant to breakage, i. H. breaking into smaller particles than the fibers. Because breaking the aspect ratio of the filler platelets and fibers are changed, this changes the performance of the electrically conductive element, which is why a as little breakage as possible is desired.

As stated above, the invention also consists in an electrically conductive element which is a matrix made of an organic material with embedded therein mica flakes coated with a conductive metal consists. In this embodiment, stand with a conductive metal coated mica flakes in operative contact to form one or more electrically conductive ones

To form pathways through the matrix. An "effective contact" is to be understood as meaning that the surfaces of adjacent coated platelets are generally in flat contact or are close to one another, so that an electron over-aana takes place from one platelet to the next. This is shown in FIG. In those embodiments in which a conductive metal coated inorganic non-metallic particles, conductive metal / with a conductive metal coated fibers and / or carbon black in addition as fillers are incorporated, there is an effective contact at a sufficient number of adjacent filling body to one or more conductive To form pathways through the matrix. It is not necessary that this contact between the fillers is of the same type, for example there is contact between coated flakes, but it is sufficient that there is contact between fillers of different types, for example coated flakes / coated fiber, coated flakes / conductive Metal particles, coated flakes, soot particles, etc. This is shown in FIG.

The size of the mica flakes coated with a conductive metal, those coated with a conductive metal inorganic non-metallic particles, fibers coated with a conductive metal and of the conductive metal particles as well as the soot particles changes during the manufacture of the electrically conductive one Body from the flowable conductive composition is not essential. AtSDielweise show at one electrically conductive element, the coated mica platelets have a largest dimension of 0.1 to 200 μ and the inorganic non-metallic particles have a largest dimension of 1 to 200 μ. The preferred sizes are discussed above.

Similarly, the distribution and the thickness of the metal layer on the mica flakes will be inorganic non-metallic particles and / or fibers as well as the amount of metal in the layer during this manufacture not significantly changed. As stated above, the thickness of the metal layer is preferably im substantially evenly. However, it is in accordance with the invention that the thickness of this layer be along the surface changes as long as the conductivity of the electrically conductive element is not significantly impaired will. Typical and preferred layer thicknesses are discussed above.

In numerous embodiments, there are 5 to 90%, preferably 5 to 50% of the total volume of the electrical conductive element of mica flakes coated with a conductive metal or such coated flakes in association with coated inorganic non-metallic particles, fibers and / or carbon black particles. the The total amount of conductive metal in the electrically conductive element is expediently at least 2% by weight, preferably at least 10% by weight and up to 90% by weight. In some embodiments, it is desirable that the total amount of the conductive material makes up at least 25% or even at least 40% by weight of the element. For numerous Applications an electrically conductive element is suitable, the mica platelets coated with a conductive metal, optionally together with the above-mentioned inorganic non-metallic ones coated with a metal Contains particles, fibers and / or soot particles, the metal at least 25, for example 2 to 16 wt .- & matters. Examples of electrically conductive elements, the platelets coated with a conductive metal inorganic non-metallic particles, coated Fibers and / or soot particles contain, show 4, 8, 12 and 16% by weight conductive metal.

Wed

-44-

In the embodiments containing conductive metal particles, it will be understood that the lower the amount of conductive metal incorporated as a platelet, particle or fiber coating _{7, the} greater the amount of metal that is present as essentially pure particles / preferably platelets, is incorporated to obtain desired electrical and other properties. In particular, when the amount of the conductive metal in the coatings is relatively low, the amount of the conductive metal of the conductive metal particles of the electrically conductive element is preferably at least 5% by weight of the element. In some embodiments, the conductive metal particles constitute at least 10% or even at least 25% of the weight of the electrically conductive element. However, it is generally preferred that as much conductive material as possible be in the form of the coating of the mica flakes, inorganic non-metallic particles and / or fibers is incorporated so that the amount of metal thus obtained for conducting electrons in the element is as large as possible.

The total amount of the conductive metal contained in the electrically conductive member of the present invention becomes is selected based on the performance data required of the component in which the element is used. The conductivity, the adhesion to the chosen substrate, the solderability, the air leakage resistance, the dispersion factor and the like that are required for the electrically conductive member to interfere with other materials compatibility should therefore be considered when choosing the total amount of conductive metal. In general, all of the above properties are enhanced when the total amount of the conductive Metal in the electrically conductive element

is increased- It goes without saying that even with an increased Content of the conductive metal to one or the other property of the electrically conductive element enlarge the electrically conductive element according to the invention:. generally comparable or superior Has properties at lower cost compared to an element whose conductive component only consists of silver or other conductive metal particles.

Another consideration when selecting the materials in some embodiments of the invention One thing to consider are the formation conditions that the flowable conductive compositions will have during manufacture of the electrically conductive element are to be subjected. Sometimes a relatively high firing temperature is required, for example an adhesion of an electrically conductive body to a substrate with which it is used will bring about. In general, the temperature at which the starting conductive composition increases It can be fired by using, in addition to mica, more highly fusible materials at high temperatures withstand, for example silicon oxide, feldspar or bauxite.

A particular advantage is that the inventive flowable conductive compositions and electrically conductive elements to a considerable extent units coated with a conductive metal with cores of mica, inorganic non-metallic material or suitable fiber material. this is in direct contrast to the known conductive pastes, in which the conductive metal component is completely is in the form of pure particles. With such

well-known conductive silver-containing pastes, does that Metal typically from 0 to 85 percent by weight. Using the above-mentioned cores becomes a significant one Proportion of the volume that has been occupied by a conductive metal by one less Formed expensive material, which results in a considerable cost saving. Despite the replacement of a substantial Amount of the conductive material that has been used in the known paste compositions by a another material is the conductivity of the electrical conductive element consisting of a flowable according to the invention conductive composition, none the less at least as large as that of one electrically conductive element which contains 90% by weight of silver and has been produced from a known paste. Furthermore, the electrically conductive element has advantageous electrical and other properties, for example in terms of conductivity, adhesion to a substrate and service life. In addition, the Invention achieved relief and cost advantages, as the for the flowable conductive composition and the Electrically conductive element usable materials are readily available, often at relatively low levels Costs. The invention therefore provides an electrically conductive element that is inexpensive Has performance characteristics and is easy to manufacture from available materials at relatively low cost is.

The following examples serve to further illustrate the invention.

An electrically conductive element containing 23.59% by weight of silver and 14.67% by volume of silver-coated mica flakes was produced according to the invention as follows. 27.21 g, acrylic resin / namely Rohm & Haas B-66 acryloid resin (50% by weight solids) and 10.11 g / silver-coated mica flakes (the mica flakes had a size of -325 US mesh plus pan and were made of with Water-milled natural mica), in which the silver made up 57.2% by weight of the coated flake, were weighed to the nearest 0.01 g using a Sartorius digital balance (model no. 1202MP). The acrylic resin and the silver-coated mica flakes were mixed manually. Toluene was added in an amount to adjust the viscosity to about 650 cPa.s. The mixture was poured onto a glass plate which had been coated with a silicone release agent, Mark V Laboratory, Inc.'s "Silicone Spray Mold Release" . The mixture was cut with a Gardener knife approximately 3-inch (7.62 cm) wide from the Paul N. Gardener Company with a gap of 0.5 mm (0.02 ") to 1.16 mm (0.040"). applied by brushing. The mixture was dried overnight at room temperature and then in an oven for at least 84 hours at 75 ⁰ C in air ausaehärtet to the qesamte solvent to remove. The dried mixture was then removed from the glass plate and cut into 11.6 cm (4 inches) long and 2.54 cm (1 inch) wide test strips. The resistance of a test strip was tested with a Hewlett-Packard Model No. 4328A milliohmmeter or a Keithley Instruments Model No. 610C electrometer. The exact thickness, length and width of the sample was measured with a micrometer and the volume resistivity was calculated from this. The average volume resistivity was 0.015 ohm-cm.

The details of the experiment described above are in the table below to the right of the note "Example 5A" given. Further tests were carried out in which one or more weight% Silver of the silver-coated mica flakes,% by weight of silver of the conductive element and% by volume of the conductive element The filler of the conductive element was varied. The details of these attempts are in the table beside the indications 5B, 5C, 6A to 6D and 7A to 7D. The electrically conductive elements used in these experiments were prepared in the same manner as above except for an appropriate one Adjustment of the amount of silver in the silver-coated mica flakes and the individual amounts the silver-coated mica flakes and the B-acryloid resin. The volume resistivities obtained (which in each case are the average of the specific Volume resistances of 4 or 5 different strips) are in the rightmost column in the table specified.

Furthermore, various test samples were obtained in the same manner as above except for the silver-coated ones Mica flakes by silver flakes (obtained from Metz Metallurgical Laboratories and im generally considered suitable for thick-film paste applications) and the quantities of silver platelets and the acrylic resin were adjusted accordingly to the details of the experiments given in the table 8A, 8B and 8C.

example Ag-coated
Glinmer platelets
(G) , 11 Ag plate
chen (g) resin
(G) , 21 Wt% Ag
per plate
chen Wt% Ag
of directing
the Elements % By volume of
senior
Filler ohm-cm
more specific
Volume resistance 5A 10 , 16 0 27 , 80 57.2 23.59 14.67 0.015 5B 15th , 52 0 23 , 41 57.2 31.24 22.76 0.0026 5C 20th , 11 0 20th , 22 57.2 37.29 31.44 0.0024 6Λ 11th , 66 0 27 , 82 30.8 13.41 20.00 0.199 6B 1b , 22 0 23 , 39 30.8 17.53 30.00 0.083 6C 22nd , 74 0 20th , 02 30.8 20.72 40.00 0.095 6D 27 , 89 0 17th , 21 30.8 23.26 50.00 0.078 7A 16 , 32 0 27 , 81 67.4 36.38 19.99 0.085 7B 25th , 76 0 23 , 41 67.4 45 29.98 0.020 7C 33 , 21 0 20th , 01 67.4 51.06 39.97 0.017 7D 42 0 17th , 25 67.4 55.55 49.98 0.0091 8A 0 42.00 22nd , 44 pure Ag
Flakes 76.63 27.27 0.190 8B 0 84.00 25th , 02 IMl 85.15 39.60 0.0015 8C 0 63.00 18th Il 85.86 40.97 0.0012

ro cn cn ro

-Sir-

Figures 5 and 6 graphically reproduce the results of the experiments described above. Figure 5 represents a diagram of the specific volume resistance of electrically conductive elements depending on the conductive filler in vol .-% in these elements. FIG. 6 is a graph of the volume resistivity of each electrically conductive element in FIG Dependence of the silver content in% by weight in the element. It can be seen that with the invention obtain a wide range of volume resistivities can be determined by the amount of silver in the silver-coated platelet, the weight of the silver in the electrically conductive element and / or the volume of the conductive filler in the electrically conductive element is varied. In contrast, the volume resistivity falls in a narrow range of the silver weight fraction and the volume fraction of the electrically conductive element steeply when silver flakes can be used as a conductive filler. This illustrates the relative simplicity with which the invention Electrically conductive elements can be produced that have a certain volume resistivity have, d. H. the volume resistivity of such electrically conductive elements does not match Has a disadvantage compared to small changes in the weight fraction of the silver or the volume fraction of the conductive filler in the electrically conductive element to be sensitive. It can also be seen that it is proportionate low volume resistivities can be obtained by the invention, compared to those who encounter electrically conductive elements which contain only pure silver flakes, where in many cases less than half the amount of silver in the electrically conductive element is used comes. This is a major factor in the cost

savings when realizing the invention.

The terms and expressions used are used for explanation and not of limitation and es is not intended by the use of these terms and expressions to be equivalents of those shown and to exclude the measures described as well as parts thereof, it will be apparent that numerous modifications are possible within the scope of the invention are.

_53 blank page

Claims (1)

Electrically conductive element, process for its manufacture and use of the same Electrically conductive element, characterized in that it consists essentially of mica platelets, which are coated with a conductive metal and embedded in a matrix made of an organic material, wherein the conductive metal coated mica flakes are in operative contact with the matrix. 2. Element according to claim 1, characterized in that the matrix comprises an acryloid resin. 3. Element according to claim 1, characterized in that it is connected to a substrate to an electrically conductive connection or film on the substrate to build. 4. Element according to any one of the preceding claims, characterized in that it consists essentially of the with a conductive metal-coated mica flakes, the coated mica flakes being at their largest Dimension have a size of 0.1 to 200 μ, as well made of an organic binder that forms a matrix with the embedded therein with a conductive metal-coated mica platelets can be reshaped, with the conductive metal particles are present in an amount which is 10 to 50% by volume of the electrically conductive Element, and the amount of conductive metal is at least 2% by weight of the element. 5. Element according to any one of the preceding claims, characterized in that it consists essentially of the with a conductive metal coated mica platelets nit a size of 0.1 to 200 μ in its largest dimension, as well as soot particles and an organic one Binder that can be formed into a matrix in which the coated with a conductive metal Mica platelets are embedded. 6. Element according to any one of the preceding claims, characterized characterized in that the conductive metal is silver. 7. Element according to claim 6, characterized in that the silver coating of the silver-coated mica flakes makes up 4 to 70% by weight. 8. Element according to any one of the preceding claims, characterized characterized in that it comprises the mica flakes coated with a conductive metal and conductive metal particles contains which Metallteilctu-n from one or Several metals are formed from a group consisting of gold, platinum, palladium, copper and their alloys consists, with both the Glimner platelets and the metal particles in a matrix of organic Material are embedded and are in effective contact with the matrix. 9. Element according to claim 8, characterized in that the Conductive metal particles consist of a coating of a conductive metal, which is on a core of a other metal is applied. 10. Element according to claim 8, characterized in that it also contains inorganic non-metallic particles coated with a conductive metal. 11. Element according to claim 10, characterized in that the coated mica particles and the coated inorganic non-metallic particles in effective Be in contact with the matrix. 12. Element according to claim 11, characterized in that the coating metal is silver, gold or copper. 13. A method for producing an electrically conductive element according to any one of claims 1 to 12, characterized in that that a flowable conductive composition of mica flakes coated with a conductive metal are and an organic binder that forms a matrix with the embedded therein with a conductive metal-coated mica flakes can be deformed, formed and the flowable conductive composition Is exposed to conditions under which the organic binder is transformed into the matrix. 14. The method according to claim 13, characterized in that the flowable conductive composition of silver coated Mica platelets with a size of 0.1 to 200 μ in their largest dimension and the organic binder is formed, which can be transformed into a matrix in which the silver-coated platelets are embedded, and that the paste formed in which the organic binder is formed into the matrix is subjected to conditions wherein the total amount of silver, which has been the flowable conductive Zusa ^T rmensetzung incorporated sufficient to at least two weight percent of the electrically conductive element to be. 15. The method according to claim 13 or 14, characterized in that the flowable conductive composition as organic binder comprises an acryloid resin. 16. The method according to claim 15, characterized in that the organic binder contains one or more solvents. 17. The method according to any one of claims 13 to 16, characterized characterized in that the flowable conductive composition is formed by a molding compound. 18. The method according to any one of claims 13 to 16, characterized in that the flowable conductive composition through a conductive paste is formed. 19. The method according to any one of claims 13 to 16, characterized characterized in that the flowable conductive mass is formed by a conductive paint. 0. The method according to any one of claims 13 to 19, characterized in that the flowable conductive mass consisting essentially of conductive metal coated mica flakes with a size of 0.1 to 200 μ in its largest dimension, as well as an organic binder that is transformed into a matrix leaves, in which the coated with a conductive metal mica platelets are embedded, the with the conductive metal coated mica flakes in the flowable conductive composition in an amount are present, which leads to them being 10 to 50% by volume of the electrically conductive element and that the amount of conductive metal in the conductive metal coating sufficient to be at least 2% by weight of the element. 21. The method according to any one of claims 13 to 20, characterized in that that the flowable conductive composition consists essentially of a conductive metal coated Mica platelets with a size of 0.1 to 2 00 μ in their largest dimension consists of soot particles and an organic binder, which can be formed into a matrix in which the with a conductive Metal layer coated mica flakes are embedded. 22. The method according to any one of claims 13 to 21, characterized in that the flowable conductive composition with a conductive metal coated mica flakes and conductive metal particles, which metal particles are formed from one or more metals selected from a group consisting of gold ₇ consists of platinum, palladium, copper or their alloys, as well as an organic binder that can be transformed into a matrix in which the coated mica platelets and the conductive metal particles are embedded. 23. The method according to any one of claims 13 to 22, characterized in that the flowable conductive composition also inorganic coated with a conductive metal Contains non-metallic particles. 24. The method according to any one of claims 13 to 23, characterized in that the conductive metal particles from one. Layer made of a conductive metal, which is applied to a core made of another metal. 25. The method according to any one of claims 1 to 24, characterized in that that the flowable conductive composition contains silver-coated mica flakes, the Silver coating makes up 4 to 70% by weight of the silver-coated platelets. 26. The method according to any one of claims 13 to 25, characterized in that that the flowable conductive mass consists essentially of coated with a conductive metal Mica flakes, as well as inorganic non-metallic ones coated with a conductive metal Particles and an organic binder, which can be transformed into a matrix in which the coated mica flakes and the coated inorganic non-metallic particles are embedded. 27. The method according to any one of claims 1 to 26, characterized in that that essentially the entire surface of the mica platelets is coated with a conductive metal is. 28. The method according to any one of claims 13 to 27, characterized in that the conductive metal at least Makes up 4% by weight of the coated platelets. 29. The method according to any one of claims 13 to 28, characterized in that the conductive metal at least 25% by weight of the coated platelets. 30. Use of an electrically conductive element according to one of claims 1 to 12, for the production of a electromagnetic shielding. 31. Use of the electrically conductive element according to one of claims 1 to 12 for the production of an article, that gives off an electrical charge.