KR20140102175A - Electrically conductive metal/plastic hybrid comprising a polymer material, a first metal and metal particles of a second metal embedded in the first metal and method of producing such - Google Patents

Abstract

The present invention is directed to a method of forming an electrically conductive metal / metal composite comprising a substrate of a polymeric material, a network embedded within the substrate and made of a metal having a first melting temperature, and a second metal layer within the network having a second melting temperature, Plastic hybrids. In addition, the present invention relates to a method for producing such a metal / plastic hybrid. Metal / plastic hybrids of the type described above are known from the prior art, but contain a high percentage of higher melting metal particles in order to achieve high electrical conductivity, which gives them high density and high heat capacity. The present invention provides metal / plastic hybrids with lower density and lower thermal capacity by using aluminum as a component of the metal particles. In addition, a process for producing such a metal / plastic hybrid is provided.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an electrically conductive metal / plastic hybrid comprising a polymer material, a first metal and metal particles of a second metal embedded in the first metal and a method of manufacturing the same. BACKGROUND OF THE INVENTION OF A SECOND METAL EMBEDDED IN THE FIRST METAL AND METHOD OF PRODUCING SUCH}

The present invention is directed to a method of forming an electrically conductive metal comprising a substrate of a polymeric material, a network embedded in the substrate and made of a metal having a first melting temperature, and a second melting temperature that is higher than the first melting temperature, / Plastic hybrids. In addition, the present invention relates to a method for producing such a metal / plastic hybrid.

Metal / plastic hybrids of the type described above are known from the prior art, but contain a high percentage of higher melting metal particles in order to achieve high electrical conductivity. Because their higher melting point metals are usually very dense, the overall metal / plastic hybrid is also very dense. In addition, the metals used in the higher melting point metal particles can be expensive, which increases the cost for the metal / plastic hybrid. In addition, these metals generally have a high thermal capacity, which makes it difficult for the resulting metal / plastic hybrids to be processed, especially in the casting process.

It is therefore an object of the present invention to provide a metal / plastic hybrid exhibiting a lower density. Another object of the present invention is to provide a less expensive metal / plastic hybrid. It is a further object of the present invention to provide a metal / plastic hybrid which is particularly easy to process in the casting process.

According to the present invention, this object is achieved by using aluminum-containing metal particles as the higher melting point metal particles.

By using aluminum as a material for the metal particles, the density of the resulting metal / plastic hybrid can be significantly reduced. In addition, aluminum is usually cheaper than metals often used for metal particles such as, for example, copper, nickel, iron or silver. In addition, because aluminum has a low thermal capacity, metal / plastic hybrids containing aluminum are easier to process and finer structures can be fabricated due to the lower volumetric heat capacity of the resulting metal / plastic hybrid. In particular, two-step processes can be performed more easily because the negative effects of heat are minimized. In particular, if delicate and fine structures are to be produced, lower heat capacity can enable better results.

Aluminum and aluminum containing compounds are generally less toxic than the materials used in metal / plastic hybrids, thus resulting in health and environmental benefits.

The solution according to the invention can each be combined in any way according to one or more of the following further advantageous embodiments.

In a first advantageous embodiment of the invention, the metal particles predominantly contain aluminum, which means that aluminum is the major component.

In an improved version of the invention, the metal particles consist only of aluminum and unavoidable impurities. The percentage of impurities is preferably less than 3% by weight, more preferably less than 1% by weight.

The aluminum-containing metal particles may be coated with a second metal. Preferably, the coating of the metal particles occurs before the particles are mixed with the low melting point metal. Such a coating can help to form better contact between the metal particles and the low melting point metal, for example, by reducing or eliminating oxide layers that may be present outside of the metal particles. In particular, the coating may contain metals that may also be found in low melting point metals. In very special cases, the coating of metal particles contains only one element and the low melting point metal is a mixture of these and other elements.

The coating of aluminum-containing metal particles can be achieved by several methods. First, the metal particles are coated by a chemical method, for example, by galvanizing. However, other coating methods such as physical vapor deposition (PVD), atomic layer deposition (ALD) or sputtering can also be used.

In a preferred refinement of the invention, the coating for the aluminum-containing metal particles may be zinc. Zinc is a common coating material for many metals, especially aluminum. Therefore, various processes for producing such a zinc coating are widely known and corresponding materials or devices are readily available. In addition, a pool of knowledge, for example process parameters to achieve a certain thickness, may already be used. Such a coating can be achieved, for example, by wet chemical methods or physical methods. Since aluminum and zinc tend to form mixed crystals, intimate connection between them and good adhesion of zinc to aluminum-containing metal particles can be achieved.

In another advantageous refinement of the invention, tin is used as the coating material for the metal particles. Aluminum and tin do not mix in the solid phase, so diffusion of the coating metal into the aluminum particles can be prevented by the use of tin. Tin is often used as a component of a low melting point metal. Thus, the use of tin as a coating material can help to create good contact between the particles and the low melting point metal. The tin coating can be applied by several methods, for example, chemically or physically.

In a further advantageous refinement of the invention, the aluminum-containing metal particles may contain two or even more coating layers. For example, the aluminum-containing metal particles may be coated with zinc in the first step and tin in the second step. Due to the mixing of aluminum and zinc in the solid phase, zinc will easily adhere to the aluminum particles. Since zinc and tin can form an eutectic system, further processing of such particles at temperatures as low as about 200 ° C can be made possible. Due to the low temperature, the manufacture of metal / plastic hybrids is further facilitated, especially if tin is used as a component of low melting point metal. In addition, the tin will not diffuse into the aluminum particles.

In a further advantageous embodiment of the invention, the metal particles are coated with tin in a first step and coated with zinc in a second step. Especially if a metal / plastic hybrid is treated at higher temperatures, such a combination may be advantageous. When the low melting point metal contains tin, the use of zinc as the second layer helps to make good contact between the metal particles and the low melting point metal.

Since the additional solder for the contact will facilitate contact with the coating material by using a material used for the solder as a coating material, such as tin, for example, solder can be used for such metal / plastic hybrid Contact formation is facilitated.

In a further refinement of the invention, the coating layer of metal particles contains a low melting point metal. If a sufficient low melting point metal is applied to the metal particles, the step of adding additional low melting point metal in another step can be prevented and the metal particles can be mixed directly with the polymer material.

In another advantageous refinement of the invention, copper may be used as the first or additional coating material for the aluminum-containing metal particles. Deposition by physical methods is preferred in this case, since it may be difficult to apply copper by chemical methods.

In yet another further advantageous refinement of the present invention, the polymer material may be thermoplastic and the first metal may be melted in the range of 100 占 폚 to 400 占 폚.

In an advantageous refinement of the invention, the addition of a flux to the metal / plastic hybrid, in particular if the aluminum-containing metal particles are not coated, will remove the oxide layers that such flux may be present on the aluminum- And can improve the flow properties of the low melting point metal in the liquid phase, thereby helping to make good contact between the aluminum containing metal particles and the low melting point metal.

Molded bodies, particularly electrical or electronic elements, which at least partially comprise a metal / plastic hybrid according to the invention can be used for a large range of applications. In particular, they may be used in electrical circuits as electrical or electromagnetic shields, castable plugs, housings, RF connectors or antennas.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail and in an exemplary manner using advantageous embodiments and with reference to the drawings. The described embodiments are merely possible configurations, but individual features such as those described in the configuration may be provided independently of each other or omitted.

1 is a schematic cross-sectional view of a first embodiment of a metal / plastic hybrid according to the present invention,
2 is a schematic cross-sectional view of a second embodiment of a metal / plastic hybrid according to the present invention.

1 is a cross-sectional view of a metal / plastic hybrid 1 according to the present invention. The metal particles (2) according to the present invention are formed as aluminum-containing metal particles (3) embedded in the low melting point metal (4). The metal particles 2 can basically have the shape of a sphere. However, they may have any other shape, and in particular they may be filaments, cubes, flakes, rods, coins, and the like. The metal particles 2 together with the low melting point metal 4 form an electrically conductive phase and can form an electrically conductive network within the metal / plastic hybrid 1 so that the entire metal / plastic hybrid 1 It is electrically conductive. Here, as usual, metals are defined as electrically conductive. Thus, the metal may be an element, an alloy, a compound or a mixture with a metal. The metal / plastic hybrid 1 may also comprise a polymer material 5, for example a thermoplastic material or resins, which may be one or more plastics materials which may be plastic deformable at elevated temperatures. According to the present invention, the metal particles 2 contain aluminum, and in particular aluminum may be the main component or the only component. However, other elements may also be present in the metal particles. By using aluminum as one of the components of the metal particles 2, the density of the metal particles 2 can be lowered. An additional advantage of aluminum is that it is usually cheaper than other metals used in the manufacture of metal / plastic hybrids, such as, for example, copper, nickel, iron or silver.

As an added advantage, aluminum has a low thermal capacity that can help promote the manufacture of components including such metal / plastic hybrids 1. In particular, if the other components of the component are negatively influenced by heat, the use of the metal / plastic hybrid 1 according to the invention can help to make such parts easier with less effort and time, The less energy required to heat the metal / plastic hybrid 1 according to the invention can save costs and save additional energy. In addition, due to the low thermal capacity of the metal / plastic hybrid according to the present invention, very fine structures can be produced by the metal / plastic hybrid. In particular, processes in which the second part may be adversely affected by heat or temperature, or where favoring the use of low temperature or less heat may be performed less efficiently, with less waste, faster and with less energy.

In an advantageous embodiment of the invention, the metal / plastic hybrid (1) may also contain flux. The flux may be on the aluminum particles and may help to remove oxide layers which may make it difficult or impossible to establish a connection between the metal particles 2 and the low melting point metal 4. [ In addition, such fluxes can provide a higher viscosity to the low melting point metal 4, which further improves the interconnection between the metal particles 2 and the low melting point metal 4.

The sizes of the metal particles 2 may be less than 200 [mu] m in the preferred embodiment. When very fine structures are to be fabricated, the size of the metal particles 2 can be further reduced. However, if for example a higher volume-to-surface ratio is desired, the size of the aluminum-containing particles 3 can be increased. Various particle sizes, such as fine and coarse mixtures, may also be used for more efficient packing and hence higher loading and / or easier handling of the metal particles.

Although the aluminum-containing metal particles 3 in Fig. 1 are not covered by the coating layer 6 around the particles in their final state of the metal / plastic hybrid 1, the aluminum-containing metal particles 3 Coating may be advantageous. For example, the aluminum-containing metal particles 3 that can expose the outer oxide layers can be coated with tin. Such a coating may be achieved by, for example, wet chemical methods such as galvanizing or physical methods such as physical vapor deposition (PVD). Since the tin is often contained in the low melting point metal 4 of the metal / plastic hybrid 1, the tin coating layer 6 can be mixed with the tin in the low melting point metal 4. [ Such a coating step can help to make better contact between the aluminum-containing metal particles 3 and the low melting point metal 4.

In an advantageous embodiment of the present invention, one of the coating layers 6 preferably contains a large amount of low melting point metal (4). Thus, the addition of the low melting point metal 4 or the mixing of the low melting point metal 4 and the metal particles 2 can be prevented since the coating layer 6 provides a sufficiently low melting point metal 4. Thus, these coated particles can be mixed with the polymeric material or inside the polymeric material, skipping one step in the fabrication process.

By using a low melting point material such as brazing solders or leads as the coating material, it is easy to connect the material to the outer parts.

In Figure 2, another advantageous embodiment of the invention is depicted. In this schematic cross-section, the metal / plastic hybrid 1 according to the present invention comprises aluminum (Al) with an additional coating layer 6 located on the interface between the aluminum-containing metal particles 3 and the low melting point metal 4 (3). ≪ / RTI > In addition, the polymer material 5, for example a thermoplastic material or resin, can be seen.

Again, the preferred size range of the aluminum-containing metal particles 3 is less than 200 [mu] m. However, by changing the size of the aluminum-containing metal particles 3 at a constant thickness of the coating layer 6, the ratio of the coating material to the material of the aluminum-containing particle metal 3 can be varied.

In a first embodiment of the invention, aluminum is a major component of the metal particles and further reduces the density of the metal particles.

In a preferred embodiment of the present invention, aluminum is the only component in the metal particles (2). Such simple particles can be easily made or easily bribed, which reduces fabrication time and costs.

In a preferred embodiment of the present invention, the aluminum-containing metal particles (3) have a zinc-containing coating layer (6). Such a zinc coating can be achieved by several methods, for example by wet chemical methods such as galvanizing, or by physical methods. Since such methods are already known and widely used, extensive knowledge of these processes exists and materials for such processes are readily available. Since aluminum and zinc can be easily mixed by forming mixed crystals, intimate and intimate contact occurs between the aluminum in the metal particles and the coating layer 6.

In many cases, tin is a component of a low melting point metal, which makes it much more advantageous to use zinc as the coating layer 6 because zinc and tin can form a process system at a melting point as low as about 200 캜. Such a low melting point helps to minimize the energy used in the manufacturing process of the metal / plastic hybrid 1. Moreover, production time and effort are also reduced by such low melting point.

In another advantageous embodiment of the invention, tin is used as the coating layer 6 for the aluminum-containing metal particles 3. Since aluminum and tin are not mixed in the solid phase, diffusion of tin into the aluminum of the aluminum-containing metal particles (3) is prevented for a long time. Therefore, certain characteristics of the metal / plastic hybrid 1 can be expected during the life of the parts made of such metal / plastic hybrids 1. In addition, since tin can be used as a component of the low melting point metal 4 in many cases, easy contact of the aluminum containing metal particles 3 to the low melting point metal can be promoted. The coating of the aluminum-containing metal particles 3 with tin can be achieved by various methods such as chemical methods or physical methods.

In an even more advantageous embodiment of the invention, the aluminum-containing metal particles 3 can be coated with more than one coating layer 6. For example, the first coating layer may be zinc to form mixed crystals with aluminum, thus establishing good contact with the other components. The second layer can be made of tin, which can form a process system with zinc, which has a low melting point and provides a good connection of zinc to the tin layer. Since tin is often used as a component of the low melting point metal 4, good contact between the second layer and the low melting point metal 4 is also provided by using tin as the second coating layer 6. The second coating layer 6 may be unique in the process of making the metal / plastic hybrid, especially when the low melting point metal 4 contains tin as one component.

Copper may also be used as the coating layer 6. If copper is used as the coating material, a physical coating process such as physical vapor deposition (PVD) may be desirable since the application of copper by chemical methods such as wet chemical methods can be difficult.

Parts or shaped bodies at least partly comprising or comprising the metal / plastic hybrid 1 according to the invention can be used for a variety of applications. Due to the electrical conductivity of such a metal / plastic hybrid 1, especially electrical circuits or electrical components are produced by methods including plastic forming, especially at elevated temperatures, of these electrical circuits or components Metal / plastic hybrids can easily be used in electrical circuits. In addition, this method is very advantageous for two-step processes such as a 2K or two-shot casting process because the metal / plastic hybrid 1 according to the present invention has low heat capacity, Allowing for faster and more efficient processing with higher precision. Components made of such metal / plastic hybrids 1 may also be used as shields for electric or electromagnetic fields. Another exemplary application of such a component made of a metal / plastic hybrid 1 can be a plug cast on an electrical circuit, an RF connector, an antenna or a conductor element of a casing.

Claims (12)

A network comprising metal particles (2) in a network having a substrate of the polymer material (5), a network embedded in the substrate and made of a metal having a first melting temperature, and a second melting temperature higher than the first melting temperature A conductive metal / plastic hybrid (1)
Characterized in that the metal particles (1) contain aluminum,
Electrically conductive metal / plastic hybrids.
The method according to claim 1,
Characterized in that the metal particles (2) are mainly composed of aluminum,
Electrically conductive metal / plastic hybrids.
3. The method according to claim 1 or 2,
The metal particles 2 contain, in addition to the impurities, only aluminum, which preferably constitutes less than 3% by weight, more preferably less than 1% by weight of the particles.
Electrically conductive metal / plastic hybrids.
4. The method according to any one of claims 1 to 3,
Characterized in that the aluminum-containing metal particles (2) are coated with at least one metal coating layer (6)
Electrically conductive metal / plastic hybrids.
5. The method of claim 4,
Characterized in that the at least one coating layer (6) contains tin.
Electrically conductive metal / plastic hybrids.
The method according to claim 4 or 5,
Characterized in that the at least one coating layer (6) contains zinc.
Electrically conductive metal / plastic hybrids.
7. A metal / plastic hybrid (1) according to any one of claims 1 to 6, comprising at least one electrically conductive section,
Electrical or electronic elements.
A method of making an electrically conductive metal / plastic hybrid (1) comprising the step of bringing together a polymer with a first metal such that a metal network results in the polymer substrate,
Characterized in that the aluminum-containing metal particles and the first metal are provided together so that the metal particles are then embedded in the metal network.
(METHOD OF MANUFACTURING ELECTRIC CONDUCTIVE METAL / PLASTIC HYBRID).
9. The method of claim 8,
Characterized in that it comprises the step of coating aluminum-containing metal particles (3) with a coating layer (6) of metal.
(METHOD OF MANUFACTURING ELECTRIC CONDUCTIVE METAL / PLASTIC HYBRID).
10. The method of claim 9,
Characterized in that the coating layer (6) of the metal of the aluminum-containing metal particles (3) contains tin.
(METHOD OF MANUFACTURING ELECTRIC CONDUCTIVE METAL / PLASTIC HYBRID).
11. The method according to claim 9 or 10,
Characterized in that the coating layer (6) of the metal of the aluminum-containing metal particles (3) contains zinc.
(METHOD OF MANUFACTURING ELECTRIC CONDUCTIVE METAL / PLASTIC HYBRID).
12. The method according to any one of claims 9 to 11,
Characterized in that the one or more coating layers (6) contain, in particular, a material of a low melting point metal in an amount sufficient to make a further addition of a low melting point metal redundant,
(METHOD OF MANUFACTURING ELECTRIC CONDUCTIVE METAL / PLASTIC HYBRID).

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