Conductive polymer particles with excellent corrosion resistance

Abstract

The present invention aims to provide conductive polymer particles having a metal layer formed on the surface thereof, which has excellent electrical conductivity, corrosion resistance, and bonding strength with polymer particles. In order to achieve the above-mentioned object, the present invention can provide conductive polymer particles including a first layer containing silver oxide formed on the surface of the polymer particle, a second layer containing copper formed on the first layer, and a third layer containing nickel or silver formed on the second layer.

Description

[Technical Field]

[0001] The present invention relates to conductive polymer particles having a conductive metal coating layer, and in particular to conductive polymer particles having a multilayer structure and excellent corrosion resistance, in which a copper metal layer is formed on the surface without an expensive palladium catalyst layer, and a nickel or silver coating layer is further formed to protect the copper metal layer, and a method for producing the same. [Background technology]

[0002] Conductive particles are widely used in electronic materials. Among them, metal particles such as copper or nickel have high conductivity and are highly cost-competitive, so they are widely used in various electronic components, such as films, adhesives, and coating slurries, which require electrical conductivity.

[0003] However, it is difficult to produce these metal particles in various sizes during the synthesis process and to maintain uniform particle size and spherical shape. This makes it difficult to produce a film or adhesive layer of uniform thickness and maintain uniform contact characteristics when manufacturing a conductive film or adhesive. Furthermore, to compensate for poor contact characteristics, metal particles are added in large volumes to the film or adhesive, but the large volume ratio of these metal particles can make the film or adhesive layer heavy and weaken the adhesive strength.

[0004] To overcome this problem, anisotropic conductive films, a type of conductive film, use conductive polymer particles in which a conductive metal layer such as copper, nickel, silver, or gold is formed on the surface of polymer particles whose size can be controlled in various ways and whose particle size can be maintained uniformly.

[0005] Anisotropic conductive films (ACFs) provide stable connections between DDI chips and various types of displays to drive the display. The conductive balls, which are conductive polymer particles used in these films, cost 20 to 30 million won per kg. One of the reasons for this is the use of expensive palladium (Pd). This is because when metal coating is applied to give the polymer particles conductivity, palladium must be used to form a catalyst layer to firmly bond the polymer particles to the metal layer. Therefore, these conductive balls are rarely used in anything other than expensive anisotropic conductive films.

[0006] Meanwhile, the metal layer coated on the surface of the polymer particles can be made of various metals, but copper has excellent conductivity close to that of silver but has the problem of being easily oxidized, while nickel has excellent corrosion resistance and is advantageous in terms of long-term reliability but has the problem of low electrical conductivity. Another metal, silver (Ag), has both excellent conductivity and corrosion resistance but is too expensive.

[0007] Thus, it is difficult to achieve a metal layer formed on the surface of a polymer particle that satisfies all of the desired qualities. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide conductive polymer particles having a metal layer formed on the surface thereof, which has excellent electrical conductivity, corrosion resistance, and bonding strength with polymer particles.

[0009] Yet another object of the present invention is to provide a method for producing conductive polymer particles, which can inexpensively form a metal layer on the surface of conductive polymer particles, which has excellent electrical conductivity, corrosion resistance, and bonding strength with the polymer particles. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides conductive polymer particles including a first layer containing silver oxide formed on the surface of polymer particles, a second layer formed on the first layer and containing copper, and a third layer formed on the second layer and containing nickel or silver.

[0011] In the conductive polymer particles according to the present invention, the polymer particles are one or more selected from the group consisting of acrylic resins, acrylonitrile resins, and styrene resins, and when analyzed with a laser scattering particle size analyzer, D 50 may be spherical in the range of 0.1 to 100 μm.

[0012] In the conductive polymer particles according to the present invention, the first layer further contains metallic silver, and the molar ratio of silver element in silver oxide to silver element in metallic silver (Ag x+ / Ag 0 (0 < x ≤ 3)) may be in the range of 1 to 20.

[0013] In the conductive polymer particles according to the present invention, the first layer may further contain tin.

[0014] In the conductive polymer particles according to the present invention, it may include a tin layer formed on the surface of the polymer particles and a silver oxide layer formed on the tin layer.

[0015] In the conductive polymer particles according to the present invention, the content of silver contained in the first layer may be 10 to 1,000 ppm of the total weight of the conductive polymer particles.

[0016] In the conductive polymer particles according to the present invention, the first layer may be discontinuous island-like on the surface of the polymer particles.

[0017] In the conductive polymer particles according to the present invention, the content of copper in the second layer may be 90% by weight or more.

[0018] In the conductive polymer particle according to the present invention, the third layer may further contain phosphorus together with the nickel.

[0019] In the conductive polymer particle according to the present invention, the third layer may contain 0.1 to 13.0% by weight of phosphorus together with nickel.

[0020] The present invention can provide a method for producing a conductive polymer, which includes: (a) a hydrophilization step of hydrophilizing the surfaces of polymer particles; (b) a first layer formation step of coating the hydrophilized surface of the polymer particles with silver oxide; (c) a second layer formation step of electrolessly plating copper on the first layer; and (d) a third layer formation step of electrolessly plating nickel or silver on the second layer.

[0021] Furthermore, the present invention can provide a method for producing a conductive polymer in which tin is coated together with the silver oxide in the step of forming the first layer.

[0022] The method for producing a conductive polymer according to the present invention may further comprise a step of forming a tin layer between the steps (a) and (b).

[0023] Furthermore, the method for producing a conductive polymer according to the present invention may further include, after step (b) and before step (c), a post-treatment step of stirring the polymer particles on which the first layer has been formed in an aqueous solution having a pH of 8 to 14 and a temperature of 20 to 80°C to adjust the amount of silver oxide. [Effects of the Invention]

[0024] The conductive polymer particles according to the present invention are inexpensive yet have excellent electrical conductivity and corrosion resistance, making them applicable to various electronic components that require electrical conductivity. They also have excellent bonding strength to the surface metal layer, making it possible to reduce the weight of the components to which they are applied and improve their electrical conductivity and reliability.

[0025] Furthermore, the method for producing conductive polymer particles provided by the present invention enables mass production of conductive polymer particles with excellent conductivity and reliability through an inexpensive process. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a scanning electron microscope image of conductive polymer particles according to an example of the present invention and a comparative example. [Figure 2] FIG. 1 is a diagram showing the results of analysis of conductive polymer particles in one example according to the present invention by X-ray Photoelectron Spectroscopy (XPS).

[0027] Best Mode for Carrying Out the Invention The following describes the configuration and operation of an embodiment of the present invention with reference to the accompanying drawings. In the following, when describing the present invention, detailed descriptions of related known functions or configurations are deemed to obscure the gist of the present invention, such detailed descriptions will be omitted. Furthermore, when a part "includes" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0028] Polymer particles can be made into particles of various shapes and sizes, but due to the nature of the material, they have no or very low electrical conductivity. To overcome this, forming a conductive metal layer on the surface makes it possible to impart conductivity to polymer particles of various shapes and sizes.

[0029] However, because polymers and metals are dissimilar materials and have very low adhesive strength, it is very difficult to form a metal layer on the surface of a polymer. To overcome this problem, a conventional method has been to form an intermediate layer between the metal layer that provides conductivity and the polymer to facilitate adhesion. These intermediate layers include a catalyst layer containing palladium. These palladium catalyst layers facilitate the formation of metal layers such as copper, nickel, and silver. However, as is well known, palladium is an expensive precious metal, and in recent years, its price has been higher than that of gold, which has led to the problem that conductive polymer particles made using palladium are very expensive.

[0030] To solve this problem, the inventors of the present invention investigated an intermediate layer that is cheaper than palladium and can provide sufficient bonding strength with the polymer surface. Silver oxide is known to be able to adhere smoothly to the polymer surface as an oxide and also to have excellent bonding strength with metals, so they developed a method in which silver oxide is formed as an intermediate layer and then a metal coating layer is formed.

[0031] As a result, it was found that when an intermediate layer of silver oxide alone or a composite of silver oxide and metallic silver is formed, the subsequently formed metal layer, a nickel layer, can bond strongly to the polymer particles, exhibiting a bonding strength equal to or greater than that when a conventional layer containing palladium is used.

[0032] Meanwhile, the characteristics of conductive polymer particles are determined by the type of metal layer formed on the surface of the polymer particles. Copper has excellent electrical conductivity but is easily oxidized, which makes reliability a problem. Nickel, on the other hand, has excellent corrosion resistance but lower electrical conductivity than copper. Silver has both excellent corrosion resistance and electrical conductivity, but is expensive. As such, it is difficult to satisfy all of the properties required in industry with just one type of metal.

[0033] In order to overcome such problems, the inventors of the present invention have invented conductive polymer particles having a multilayered metal layer formed on the surface thereof, in which a copper metal layer is formed first, and then a nickel or silver metal layer is formed on the copper metal layer to protect the copper metal layer.

[0034] As a result, the present invention can provide conductive polymer particles comprising a first layer containing silver oxide formed on the surface of the polymer particle, a second layer containing copper formed on the first layer, and a third layer containing nickel or silver formed on the second layer.

[0035] The polymer particles constituting the core of the conductive polymer particles are one or more selected from the group consisting of acrylic resins, acrylonitrile resins, and styrene resins, and when analyzed with a laser scattering particle size analyzer, D 50 The particles may be spherical with a diameter ranging from 0.1 to 100 μm.

[0036] Conductive polymer particles are advantageous for application to various electronic components because they have low density and can be formed into spherical particles of various particle sizes. Therefore, the polymer particles constituting the core are preferably acrylic resin, acrylonitrile resin, or styrene resin. These are all commonly available in spherical products of various particle sizes, and their use allows for the production of various spherical conductive polymer particle products. Spherical polymers have the advantages of good filling and flowability, and the ability to maintain consistent electrical conductivity in various directions. Furthermore, acrylic, acrylonitrile, or styrene resins have excellent chemical resistance, preventing deformation during the process of forming the conductive coating, allowing them to be used regardless of the environment of the component to which they are applied.

[0037] In particular, PMMA (Poly(methyl methacrylate)), an acrylic resin, is spherical and readily available in a wide variety of particle sizes. It has been proven in various fields and can be commercialized into various conductive polymer particles. PS (Polystyrene) and PAN (Polyacrylonitrile) also have stable chemical resistance and are available in a wide variety of particle sizes, making them suitable for commercialization into various conductive polymer particles.

[0038] Furthermore, when analyzed by a laser scattering particle size analyzer, the particle size of these polymer particles in the present invention is D 50 The standard is 0.1 to 100 μm, where D 50 D means the particle size when the cumulative percentage of particles reaches 50%. 50 Based on this, if the particle size of the polymer particles is less than 0.1 μm, excessive aggregation between the polymer particles occurs, making handling difficult, and the increased specific surface area makes it difficult to form a surface metal layer. On the other hand, if the particle size exceeds 100 μm, the specific surface area decreases, reducing the amount of the metal layer formed on the surface, and it may not be possible to obtain the desired electrical conductivity.

[0039] As mentioned above, the surface of polymer particles is difficult to bond with a metal layer due to the characteristics of the material. To modify such surface properties, a catalyst layer must be formed. In the present invention, a first layer, which is a catalyst layer containing silver oxide, is formed first, rather than the conventional catalyst layer containing palladium. Silver oxide has excellent bonding properties not only with polymers but also with metals, so it is possible to maintain a strong bond between the polymer constituting the core and the metal layer on the surface.

[0040] In the present invention, the first layer containing silver oxide may further contain tin. Tin is an element used to guide the smooth adhesion of silver oxide to the surface of polymer particles. When performing a coating operation with an aqueous solution, it imparts hydrophilicity to the surface of the polymer particles, thereby assisting the adhesion of silver elements to the surface of the polymer particles. These tins can also constitute the first layer together with silver oxide, or may be formed between the first layer containing silver oxide and the surface of the polymer particles.

[0041] The first layer containing silver oxide in the present invention may further contain metallic silver together with silver oxide. When metallic silver is further contained, the bond with copper, which is the metal contained in the second layer, can be further strengthened. Silver oxide strengthens the bond with the polymer, and metallic silver strongly bonds with these silver oxides and provides a strong bond with copper, which is the same metal. As a result, the bonding force between the second layer containing copper and the polymer particles is further strengthened.

[0042] At this time, the molar ratio of silver element in silver oxide to silver element in metallic silver in the first layer (Ag x+ / Ag 0 (0 < x ≤ 3)) is preferably in the range of 1 to 20.

[0043] As described above, although containing metallic silver strengthens the bond between the first layer containing silver oxide and the second layer containing copper, if the proportion of silver element in metallic silver is too high compared to the silver element in silver oxide, the bonding force between the first layer and the surface of the polymer particles due to silver oxide decreases accordingly, which is not preferable. Therefore, the molar ratio of silver element in metallic silver to silver element in silver oxide is preferably 1 to 20, more preferably 1 to 10, and still more preferably 2 to 5, so that the proportion of silver element in silver oxide is higher. The measurement of these molar ratios can be performed by X-ray Photoelectron Spectroscopy (XPS).

[0044] Here, the oxidation number of silver in silver oxide can range from +1 to +3, and in the amorphous phase, the oxidation number does not need to be a constant, so the oxidation number of silver in silver oxide may be greater than 0 and less than or equal to 3.

[0045] The first layer may further contain palladium, which further strengthens the bond between the surface of the polymer particle and the silver oxide and the bond between the second layer and the silver oxide. In this case, the amount of palladium contained may be even less than that contained in conventional conductive polymer particles without silver oxide. For example, the amount of palladium used in the manufacturing process of conventional conductive polymer particles is generally in the range of 100 to 1,000 ppm based on the conductive polymer particle, but the amount of palladium used in the conductive polymer particles of the present invention may be greater than 0 and less than 50 ppm.

[0046] The content of silver in the first layer may be 10 to 1,000 ppm based on the total weight of the conductive polymer particles.

[0047] The metallic silver or silver oxide formed in the first layer must have a certain content or more in order to provide a satisfactory level of bonding strength to the second layer, and if the content is too high, the process cost increases, which is undesirable. More preferably, it may be 10 to 500 ppm.

[0048] The first layer in the present invention may be in the form of discontinuous islands formed on the surface of the polymer particles. The first layer is a layer that strengthens the bonding strength between the polymer particles and the second layer that imparts electrical conductivity, and even if it is in the form of discontinuous islands, it can provide sufficient bonding strength to the second layer.

[0049] On the other hand, the first layer may be in the form of a continuous film, but in this case, the first layer must occupy at least 50% of the surface area of ​​the polymer particle, because even if it is in the form of a continuous film, it must occupy at least 50% of the particle surface area in order to provide sufficient bonding strength to the second layer.

[0050] A second layer containing copper, a metal with excellent electrical conductivity, is formed on the first layer containing silver oxide. Copper, among metals, has particularly excellent electrical conductivity, which allows the conductive polymer particles to have excellent electrical conductivity.

[0051] The copper-containing second layer may account for 5 to 40% by weight of the entire conductive polymer particle, but if it is less than 5% by weight, electrical conductivity may decrease, and if it exceeds 40% by weight, the density of the entire conductive polymer particle increases, increasing the risk of the second layer falling off, which is undesirable. Therefore, the content of the second layer in the conductive polymer particle is preferably 10 to 30% by weight, more preferably 10 to 20% by weight.

[0052] On the other hand, in the present invention, the copper content in the second layer containing copper is 90% by weight or more, because if it is less than 90% by weight, the electrical conductivity of the second layer decreases.

[0053] In the present invention, a third layer containing nickel or silver may be further formed on the second layer containing copper.

[0054] The third layer containing nickel or silver prevents the metallic copper formed in the second layer from oxidizing and also has excellent electrical conductivity, ultimately ensuring that the conductive polymer particles have both electrical conductivity and reliability.

[0055] When a metal layer containing nickel, which has excellent corrosion resistance, is formed as the third layer, it protects the second layer and, by forming metallic nickel, ensures a certain level of conductivity.

[0056] These third layers may contain not only nickel but also phosphorus. However, the inclusion of phosphorus slightly reduces electrical conductivity, but improves chemical resistance and oxidation resistance. Therefore, when used in components where reliability is important, it is preferable for the third layer to contain phosphorus in addition to nickel. If phosphorus is included, the phosphorus content in the third layer is preferably 0.1 to 13.0 wt. %. If it is too low, the desired improvement in chemical resistance and oxidation resistance will not be achieved, and if the phosphorus content exceeds 13 wt. %, sufficient electrical conductivity will not be obtained. More preferably, the phosphorus content is 0.5 to 6 wt. %.

[0057] Meanwhile, the third layer may contain metallic silver instead of nickel, but silver is ideal in terms of properties, as it is a metal with excellent corrosion resistance and electrical conductivity, but it has the disadvantage of being expensive. Therefore, if silver, which has excellent electrical conductivity, is formed as the third layer on top of the second layer made of copper, which has the same level of electrical conductivity as silver, while protecting the copper, it is possible to minimize the amount of silver used, ensure reliability, and maximize the conductivity of the conductive polymer particles.

[0058] The present invention can also provide a method for producing a conductive polymer, including: (a) a hydrophilization step of hydrophilizing the surfaces of polymer particles; (b) a first layer formation step of coating the hydrophilized surface polymer particles with silver oxide; (c) a second layer formation step of electrolessly plating copper on the first layer; and (d) a third layer formation step of electrolessly plating nickel or silver on the second layer.

[0059] To produce conductive polymers, a hydrophilization step is first required, in which chemical functional groups such as -OH, -COOH, -NH2, and NH3 are introduced to the surface of polymer particles to make them hydrophilic. This hydrophilization step can be carried out in a strong alkaline aqueous solution with a pH of 12 or higher. This is because the strong alkaline solution partially cleaves the polymer bonds on the polymer surface, facilitating the attachment of chemical functional groups to the surface of the polymer particles. Therefore, a strong alkaline atmosphere with a pH of 12 or higher is preferred for treating the surface of stable polymer particles.

[0060] On the other hand, although the hydrophilization treatment of polymer particles can be carried out in a strong alkaline aqueous solution as described above, the hydrophilization can also be carried out in a dry manner by modifying the surface of the polymer particles by plasma treatment.

[0061] After the hydrophilization treatment, a first layer containing silver oxide is formed, and tin can be coated along with the silver oxide, which can increase the bonding strength of the silver oxide on the surface of the hydrophilized polymer particles.

[0062] For more precise control, a tin layer can be formed first on the surface of the hydrophilized polymer, followed by the formation of a first layer containing silver oxide.

[0063] The first layer containing silver oxide can be formed in an alkaline aqueous solution with a pH of 8 or higher. This is because silver oxide is well formed in an alkaline atmosphere with a pH of 8 or higher. More preferably, the first layer can be formed in an aqueous solution with a pH in the range of 9 to 11.

[0064] Furthermore, the method for producing a conductive polymer may further include a post-treatment step, after step (b) and before step (c), of stirring the polymer particles on which the first layer has been formed in an aqueous solution having a pH of 8 to 14 and a temperature of 20 to 80°C to adjust the amount of silver oxide.

[0065] When the first layer is formed in an aqueous solution, silver ions in the aqueous solution may be reduced and adhere to the polymer surface as metallic silver rather than silver oxide. If the proportion of metallic silver is too high, the bonding strength between the polymer particles and the first layer may be weakened, which is undesirable. Therefore, to increase the silver oxide content to a desired level, the amount of silver oxide can be adjusted by treating the polymer with an alkaline aqueous solution at an appropriate temperature.

[0066] By adjusting the amount of silver oxide in this manner and then forming a second layer containing conductive copper, it becomes possible to provide conductive polymer particles that have excellent bonding strength between the metal coating layer that imparts conductivity and the polymer. DETAILED DESCRIPTION OF THE INVENTION

[0067] In order that the present invention may be fully understood, preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0068] The examples of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in various different forms, and the scope of the present invention is not limited to the following examples. Rather, these examples are provided to make the present disclosure more complete and thorough, and to fully convey the concept of the present invention to those skilled in the art.

[0069] [Example 1] 50 g of sodium hydroxide was added to 100 g of deionized water and the temperature was raised to 60°C. 50 10 g of spherical PMMA (manufactured by Sonjin Chemical Co., Ltd.) with a diameter of 20 μm was added and stirred for 10 hours to hydrophilize the surfaces of the PMMA particles. The hydrophilized PMMA particles were then collected, stirred in 100 g of deionized water, washed three times, and then collected.

[0070] The collected PMMA particles were added to an aqueous solution of 100 g of deionized water, 1.5 g of stannous chloride (SnCl2·2H2O), and 6 ml of hydrochloric acid (35% HCl solution), and stirred for 30 minutes to form a tin layer. The temperature of the aqueous solution was maintained at 35°C.

[0071] After filtering and recovering the PMMA particles with the tin layer, 0.15 g of silver nitrate (AgNO3) dissolved in 100 g of deionized water was added to the solution and stirred. At this time, 28% ammonia water was added dropwise to adjust the pH to 9.8.

[0072] The temperature was maintained at 40°C and the mixture was stirred for 1 hour to form a silver oxide layer. After 1 hour, the mixture was filtered and collected, then stirred with 200 g of deionized water and washed three times before being collected. A portion of the powder with the silver oxide layer formed was sampled and subjected to surface analysis by X-ray photoelectron spectroscopy (XPS).

[0073] The powder with the silver oxide layer formed was collected and a copper coating layer was formed using electroless plating. A copper sulfate complex solution was prepared by adding 40 g of EDTA (Ethylene-diamine-tetraacetic acid), 30 g of NaOH, and 20 g of copper sulfate to 300 g of deionized water, and the polymer particles with the silver oxide layer formed were added. While stirring, a formaldehyde solution was dripped in as a reducing agent to form a copper coating layer.

[0074] A nickel coating layer was further formed on the polymer particles with the copper coating layer. To this end, the powder with the copper coating layer was added to a nickel plating solution prepared by adding 20 g of nickel chloride (NiCl2·6H2O), 10 g of sodium acetate, 5 g of maleic acid, 30 g of sodium hypophosphite (a reducing agent), and 3 ml of lead acetate to 300 g of deionized water, and the powder was then stirred and maintained at 70-90°C for 2 hours for electroless plating.

[0075] [Example 2] The process up to the formation of the copper coating layer was the same as in Example 1, and then a silver-containing coating layer was formed by electroless plating. To this end, a silver coating solution was prepared by adding 2 g of EDTA (Ethylene-diamine-tetraacetic acid), 2.5 ml of 28% ammonia water, and 3 g of silver nitrate (AgNO3) to 300 g of deionized water. The polymer particles with the copper coating layer formed thereon were then added to the solution, and while stirring, a reducing solution prepared by dissolving 10 g of glucose and 2 g of sodium hydroxide in 50 g of deionized water was dripped in for 1 hour to form a third silver-containing layer.

[0076] [Example 3] As in Example 1, after the first layer containing silver oxide was formed on the surface of the PMMA particles, post-treatment was performed with an alkaline aqueous solution. For the post-treatment, 28% ammonia water was added to 100 g of deionized water and maintained at 60°C, after which the PMMA particles with the first layer formed were added and stirred. The pH of the aqueous solution before adding the PMMA particles was 9.5.

[0077] Thereafter, the second layer containing copper and the third layer containing nickel were formed in the same manner as in Example 1.

[0078] [Comparative Example 1] As in Example 1, a hydrophilic treatment and a tin layer were formed. Then, without forming a silver oxide layer, electroless plating was immediately performed to sequentially form a second layer containing copper and a third layer containing nickel. The electroless plating of copper and nickel was performed in the same manner as in Example 1.

[0079] Comparative Example 2 As in Example 1, a first layer containing silver oxide was formed on the surface of the PMMA particles. Then, ascorbic acid was added to the aqueous solution to convert part of the silver oxide on the surface into metallic silver. Then, electroless plating was performed to sequentially form a second layer containing copper and a third layer containing nickel. The copper and nickel electroless plating was performed in the same manner as in Example 1.

[0080] Comparative Example 3 As in Example 1, the copper coating layer was formed, but no subsequent steps were carried out.

[0081] After forming a first layer on the conductive polymer particles, the silver ratio between silver oxide and metallic silver, the silver content, nickel content, and phosphorus content were analyzed, and the coating condition was observed using a scanning electron microscope (SEM). The silver ratio was determined by analyzing samples taken after forming the first layer using XPS. The silver content, nickel content, and phosphorus content were analyzed using an inductively coupled plasma mass spectrometer (ICP).

[0082] The reliability was evaluated by a reflow test in which a certain amount of the conductive polymers prepared in Examples 1 to 3 and Comparative Examples 1 and 2 was mixed with an acrylic binder, coated on a polyimide film, dried, and then placed on molten lead for 30 seconds, after which the conductivity was measured.

[0083] The results are shown in Table 1 below. Here, the Cu content indicates the weight percentage of copper element based on the entire conductive polymer.

[0084] [Table 1]

[0085] Figure 1 shows scanning electron microscope images of conductive polymer particles according to the examples. Figure 1(a) is a scanning electron microscope image of a sample according to Example 1, Figure 1(b) is a scanning electron microscope image of a sample according to Example 2, and Figure 1(c) is a scanning electron microscope image of a sample according to Comparative Example 2.

[0086] Both the samples of Examples 1 and 2 show that a dense coating layer was formed, but in Comparative Example 2, which has a high content of metallic silver in the first layer, the coating layer is not dense and the bonding is not strong.

[0087] FIG. 2 shows the results of measuring the ratio of silver element between silver oxide and metallic silver in the first layer of the sample according to Example 1. As a result of XPS, it can be measured by the ratio of the peaks of the ratio of silver in the reduced state and the ratio of silver in the oxidized state. These molar ratios (Ag x+ / Ag 0 ) was 3.80.

[0088] On the other hand, as shown in Table 1, corrosion resistance was evaluated by a reflow test. In Examples 1 to 3, the resistance of the film using conductive polymer particles was good, at 100 mΩ or less, even after the reflow test. However, in Comparative Example 2, in which the formation of the coating layer was unstable, the resistance increased significantly, and in the sample of Comparative Example 3, in which the third protective layer was not formed, the resistance was too high to be measured.

Claims

1. a first layer comprising silver oxide formed on the surface of the polymer particles; a second layer formed on the first layer and comprising copper; a third layer formed on the second layer and including nickel or silver; Including, Conductive polymer particles.

2. The polymer particles are at least one selected from the group consisting of acrylic resins, acrylonitrile resins, and styrene resins, and when analyzed with a laser scattering particle size analyzer, ５０ is spherical in the range of 0.1 to 100 μm, The conductive polymer particles according to claim 1 .

3. The first layer further contains metallic silver, and the molar ratio of the silver element in the silver oxide to the silver element in the metallic silver (Ag ｘ＋ / Ag ０ (0<x≦3)) is in the range of 1 to 20; The conductive polymer particles according to claim 1 .

4. the first layer further comprises tin; The conductive polymer particles according to claim 1 .

5. The content of silver in the first layer is 10 to 1,000 ppm based on the total weight of the conductive polymer particles. The conductive polymer particles according to claim 1 .

6. the third layer further contains phosphorus together with the nickel; The conductive polymer particles according to claim 1 .

7. the third layer contains 0.1 to 13.0 wt % phosphorus; The conductive polymer particles according to claim 6 .

8. (a) a hydrophilization step of hydrophilizing the surface of polymer particles; (b) forming a first layer by coating silver oxide on the polymer particles whose surfaces have been hydrophilized; (c) forming a second layer by electrolessly plating copper on the first layer; (d) forming a third layer by electrolessly plating nickel or silver on the second layer; Including, Method for producing conductive polymer particles.

9. The method further comprises forming a tin layer between steps (a) and (b). The method for producing the conductive polymer particles according to claim 8 .

10. and after step (b) and before step (c), further comprising a post-treatment step of stirring the polymer particles on which the first layer has been formed in an aqueous solution having a pH of 8 to 14 and a temperature of 20 to 80° C. to adjust the amount of silver oxide. The method for producing the conductive polymer particles according to claim 8 .

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