EP0131544B1 - Electrically conductive filling agent - Google Patents

Description

Various areas of application require electrically conductive plastic systems which, in addition to having good electrical properties, also have good mechanical strengths. Known electrically conductive fillers, for example metal powder, have very good electrical conductivities, but are difficult to incorporate into plastics due to their poor dispersibility, result in inhomogeneous systems, can have a negative influence on the mechanical properties and promote the catalytic decomposition of the plastics.

It has now been found that pyrolyzing a mixture of a metal phthalocyanine and a certain inorganic filler gives electrically conductive products which are outstandingly suitable as electrically conductive fillers for plastic systems and for inorganic material. Such products have the advantages of the inorganic fillers already successfully used today to improve the mechanical strength of plastics or inorganic materials and are electrically conductive due to the well-adhering coating of pyrolyzed phthalocyanine. They can also be incorporated perfectly, resulting in homogeneous systems and not causing them to decompose.

The invention thus relates to a method for producing an electrically conductive filler, characterized in that a mixture of at least one metal phthalocyanine and at least one inorganic filler is pyrolyzed.

Suitable metal phthalocyanines are e.g. B. copper, iron, nickel, aluminum, cobalt, manganese, tin, silicon, germanium, lead, titanium, chromium, uranium, magnesium, vanadium, molybdenum or Zinc phthalocyanines, mixtures of two or more different metal phthalocyanines also being possible. The metal phthalocyanines can also be mixed with metal-free phthalocyanines. It is also possible, for example, to use metal phthalocyanines substituted with sulfonic acid, sulfonamide, sulfoester, alkyl, aryl, aryl ether or thioether residues. The metal phthalocyanines can be used in fine or coarse form. For the electrically conductive fillers according to the invention, the metal phthalocyanine used is preferably copper, nickel, cobalt or iron phthalocyanine, but very preferably copper phthalocyanine, in particular crude β-copper phthalocyanine for economic reasons.

Suitable organic fillers are, in particular, glass, quartz, clay minerals, feldspar, silicates, carbonates, rock flour, clay, oxides or sulfates, which can be synthetic or natural materials, such as. B. quartz powder, mica, talc, feldspar, perlite, basalt, asbestos, slate flour, kaolin, wollastonite, chalk powder, dolomite, gypsum, lava, magnesium carbonate, heavy spar, bentone, silicic acid airgel, lithopone, diatoms, metal oxides such as magnesium aluminum, titanium -, Zinc, iron, boron, nickel, chromium, zirconium, vanadium, tin, cobalt, antimony, bismuth or manganese oxides, as well as their mixed oxides, also metal sulfides such as zinc, silver or Cadmium sulfide, glass powder, glass balls, glass fibers, silicon carbide or cristobalite. The fillers mentioned can be used individually or in mixtures and can be fibrous, granular or powdery.

Aluminum oxide, wollastonite, titanium dioxide, mica, iron oxide or quartz, in particular finely divided quartz, are preferably used as fillers.

Of particular interest are electrically conductive fillers produced according to the invention, in which the inorganic filler is crystalline or amorphous quartz with a particle size of 0.01 to 1000 μm, preferably 2 to 200 μm.

The electrically conductive fillers that can be used in accordance with the invention can be produced by intimately mixing the pigment to be pyrolyzed and the inorganic filler dry or in an aqueous suspension, optionally with grinding, and then, if working in an aqueous suspension, filtering and drying . If necessary, the inorganic filler can be added during the synthesis of the metal phthalocyanine.

5 to 99, in particular 10 to 50 parts by weight of the pigment to be pyrolyzed are preferably used per 100 parts by weight of dry starting mixture. The mixture of inorganic filler and metal phthalocyanine thus obtained is then pyrolyzed, the inorganic filler being coated with pyrolyzed pigment. The pyrolysis can be carried out at 0.5 to 20 bar, preferably at normal pressure, in air, in inert gas, in air with an increased oxygen content or in hydrogen gas. Pressure, gas and temperature increase as a function of time are generally chosen so that the pigment pyrolyzes in the highest possible yield of carbon and metal. Air or nitrogen are particularly suitable as the gas. The pyrolysis is expediently carried out at temperatures from 650 to 2500 ° C., preferably at temperatures from 800 to 1200 ° C. The process according to the invention preferably takes place at temperatures of 650 to 2500 ° C., at a pressure of 0.5 to 20 bar and in air, inert gas, in air with increased oxygen content or in hydrogen gas, but very preferably at 800 to 1200 ° C. and at normal pressure in air instead. For example, heating a 1: 1 mixture of quartz powder / Cu phthalocyanine in air to 1050 ° C (at normal pressure) gives a product consisting of approximately 61% by weight of silicon dioxide, 30% by weight of carbon, 6.4 % By weight copper and 2.6% by weight nitrogen. The electrical conductivity at room temperature is approximately 10 Q-1 cm- ¹ .

Depending on the mixing ratio of pigment / filler, the pyrolysis product is obtained in continuous or loose, dark gray to black solid mass and is usually broken and pulverized.

The electrically conductive fillers produced according to the invention are particularly suitable for incorporation into high-molecular organic or inorganic material. As a high molecular organic Material are suitable for. B. cellulose ethers and esters, such as ethyl cellulose, acetyl cellulose, nitrocellulose, polyamides, copolyamides, polyethers and polyether amides, polyurethanes or polyesters, natural resins or synthetic resins, in particular urea and melamine / formaldehyde resins, epoxy resins, alkyd resins, phenoplasts, polyacetals, polyvinyl alcohols, polyols -, -Stearate, -benzoate, -maleate, polyvinylbutyral, polyallylphthalate, polyallylmelamine and their copolymers, polyphenyloxides, polysulfones, halogen-containing vinyl polymers such as polyvinylchloride, polyvinylidene chloride, polyvinylfluoride as well as polychloroprene and chlorinated rubbers, also polycarbonates, polyolefins, and polystyrene, such as polylylene, such as POlyl , Polyacrylic acid esters, thermoplastic or curable acrylic resins, rubber, bitumen, casein, silicone and silicone resins, individually or in mixtures. The high-molecular compounds mentioned can exist as plastic masses, melts or solutions. The conductive fillers produced according to the invention can be added to the high-molecular organic material by the methods customary in the art, before or during shaping, or also as a dispersion or in the form of preparations. Depending on the purpose, you can add other substances, such as. B. light stabilizers, heat stabilizers, plasticizers, binders, pigments and / or dyes, carbon black, flame retardants or other fillers. Based on the high molecular weight organic material, the electrically conductive filler according to the invention is preferably used in an amount of 0.5 to 70, preferably 15 to 60 percent by weight (per total mixture). The additives can also be added before or during the polymerization.

Epoxy resins which are hardened with dicarboxylic acid anhydrides are preferably used as resin / hardener components.

As an inorganic material in which the electrically conductive fillers produced according to the invention can be incorporated, for. B. cement, concrete, glasses, ceramic materials, inorganic polymers such as polysilicic acid or polyphosphoric acid derivatives, alone or in a mixture with organic polymers, such as asphalt, mentioned. Based on the inorganic material, the electrically conductive fillers produced according to the invention are preferably used in an amount of 5 to 70, preferably 15 to 60 percent by weight (per total mixture).

With the fillers produced according to the invention, plastic systems with excellent mechanical and electrical properties can be produced economically. They have a reinforcing effect on the carrier material and are characterized by good electrical conductivity. Certain plastics, for example epoxy resins, containing the fillers according to the invention also have a constant electrical conductivity over a wide temperature range.

Casting resin compositions, for example epoxy casting resins, containing the fillers produced according to the invention also have good processing properties even with high conductivity (for example no or only low thixotropy) and lead to molded parts without a reduction in the mechanical properties.

If appropriate, the fillers obtained according to the invention can be incorporated into plastics in a mixture with metals, for example in the form of powders, chips or fibers. The metal to be used here and its concentration depend on the area of application and should not impair the mechanical properties and the resistance, for example, to the decomposition of the plastic products produced with it. These are, for example, steel fibers and / or aluminum flakes. Instead of metals, carbon fibers can also be used.

The electrical conductivity can be specifically adjusted by dilution with the fillers mentioned at the beginning or by adding graded amounts of the fillers produced according to the invention in such plastics or in inorganic materials, for example in such a way that electrically partially conductive compositions are formed. This is particularly important for controlling electrical fields and / or for reducing surface or space charges.

The electrically conductive fillers produced according to the invention are not only suitable for the production of antistatic and electrically conductive polymer compositions, plastic articles and coatings. They can also be used to manufacture batteries and other objects in microelectronics, in or as sensors, as catalysts for certain chemical reactions, for the production of solar collectors, for shielding sensitive electronic components and high-frequency fields [EMI shielding], for equipotential bonding and glow protection higher load capacity of electrical systems and machines, for controlling electrical fields and charges in electrical devices or as surface heating conductors.

The following examples illustrate the invention. Parts mean parts by weight and percentages percent by weight.

Example 1: 90 parts of quartz powder Wllb from SIHELCO AG (SH-Birsfelden) are mixed well with 90 parts of crude β-copper phthalocyanine for 30 minutes on a Turbula machine from WA Bachofen (CH-Basel). The mixture is heated in a quartz glass vessel, the lid of which has a small opening, in an oven to 1050 ° C. within 6 hours. After 0.5 hours at this temperature, the mixture is cooled and 157 parts are obtained, a gray-black, solid mass which is pulverized in a laboratory mixer. The powder has a composition of 61.5% by weight SiO ₂ , 30% by weight C, 6.5% by weight Cu and 2% by weight N The electrical conductivity, measured on the compressed powder, is Room temperature 10 Scm- ¹ (2 electrodes measurement on micropressling).

Examples 2 to 4: If the procedure is analogous to that described in Example 1, but the compounds given in Table 1 are used as the starting mixture, gray-black powders having the electrical conductivities listed in Table 1 are obtained.

.Cu-Pc = Kupferphthalocyanin " gemäss F. Beck, "Berichte Bunsengesellschaft, Physikalische Chemie" 68 (1964), Seiten 558-567.

Cu-Pc = copper phthalocyanine "according to F. Beck," Bunsen Society Reports, Physical Chemistry "68 (1964), pages 558-567.

Example 5: 50 parts Wl ^® from SIHELCO AG (Birsfelden CH-) are thoroughly mixed together with 50 parts of nickel phthalocyanine for 30 minutes on a Turbula machine from WA Bachofen (CH-Basel). The mixture is heated in a quartz glass vessel, the lid of which has a small opening, to 1000 ° C. in an oven within 6 hours. The mixture is kept at 1000 ° C. for 1 hour and then allowed to cool to room temperature. This gives 86.2 parts of a gray-black solid mass which is powdered. The electrical conductivity of the powder thus obtained is 12 Scm- ¹ at room temperature ^.

^* Pc = PhthalocyaninExamples 6-10: If the procedure is analogous to that described in Example 5, but using the compounds given in Table 2 as the starting mixture, gray-black powders having the electrical conductivities given in Table 2 are obtained.

^* Pc = phthalocyanine

EXAMPLE 11 If the procedure is as described in Example 5, but nitrogen is slowly passed through the reaction vessel during the pyrolysis, a gray-black powder with similar properties is obtained.

Example 12: 270 parts of an analogous manner to Example 1 produced the filler from 135 parts of quartz powder W12 ^® from SIHELCO AG and 135 parts of the obtained in Example 1 electrically conductive powder are added to 100 parts of Araldite CY 225 ^® (modified bisphenol A epoxy resin having an Molecular weight of 380) and 80 parts of the hardener HY 925® (modified dicarboxylic anhydride). The mixture is heated to 80 ° C., homogenized with a paddle stirrer and vented for 3 minutes. The mixture is then poured into molds preheated to 80 ° C and cured for 4 hours at 80 ° C and for 8 hours at 140 ° C (DIN No. 16945). The following data are measured on the martensets and plates produced in this way:

Example 13: For the coloring of PVC, a mixture of 65 parts of stabilized PVC, 35 parts of dioctyl phthalate and 25 parts of the product obtained according to Example 1 is used

produced and moved back and forth between two rolls of a rolling calender at approx. 150 ° C for 5 minutes. The soft PVC film obtained in this way has a specific surface resistance R _o , measured according to DIN 53482 (electrode arrangement A), of 5.5. 10 ¹⁰ 2 cm.

EXAMPLE 14 25 parts of the product obtained according to Example 1, 37.5 parts of polyethylene wax AC-617 ⁰ from Allied Chemicals and 125 parts of sodium chloride are kneaded at 80-110 ° C. for 6 hours in a 300-part laboratory kneader. Then 62.5 parts of MOPLEN MOB-120 ^® from Montecatini are incorporated into the plasticine. The kneading compound is cooled to 30 ° C in the running kneader, a gray-black powdery mass is formed, which is finely pulverized with approx. 3 liters of water on a FRYMA Z 050 toothed colloid mill. The suspension obtained is filtered off and the presscake is washed free of chloride with water. The product obtained is dried in a vacuum drying cabinet at 50-60 ° C. This gives 120 parts of a fine, loose, gray-black polyolefin preparation which, after extrusion on a laboratory extruder (Temp.Zone 1: 160 ° C; Zone 2: 190 ° C; Zone 3: 220 ° C; Zone 4: 170 ° C), is a thermoplastic Mass results. This mass has an electrical volume resistance of approx. 4 - 10 ⁵ Ωcm, and is excellently suited for the production of injection molded articles or fibers.

Example 15: In a 300 parts by volume of comprehensive laboratory kneader, 32 parts of the product obtained according to Example 1, 48 parts DYNAPOL ^® 206 of the company Dynamit Nobel, 160 parts of sodium chloride and 25-32 parts by volume of diacetone alcohol for about 5 hours at Kneaded at 80 ° C. Water is then added dropwise in the running kneader and at the same time cooled until the kneading mass is converted into granules. The granules are ground on a FRYMA dental colloid mill Z 050 with plenty of water, filtered off, the press cake obtained is washed salt-free with water and then dried in a vacuum drying cabinet at 65-70 ° C. A gray-black powdery mass is obtained, which is extruded into a cord on a laboratory extruder and then granulated on a chopping machine. The 40% polyester preparation thus obtained has an electrical volume resistance of 10 ⁴ to 10 ⁵ Qcm.

EXAMPLE 16 If the procedure is analogous to that of Example 1, but using 5 parts of quartz powder W1® instead of 90 parts and 95 parts of β-copper phthalocyanine instead of 90 parts, a product containing about 12% by weight of copper is obtained. It is an excellent catalyst for the reaction described in Example 17 for the preparation of an anthraquinoid wool dye.

Example 17: Reaction scheme 20.2 parts of 1-amino-4-bromoanthraquinone-2-sulfonic acid sodium are stirred with 300 parts of water and, after the addition of 13.8 parts of sodium carbonate, 11.25 parts of I-aminobenzene-4-sulfonic acid are gradually added. 7 portions of 1 part each of the product obtained according to Example 16, finely powdered, are added to the mixture heated to 85 ° C. as a catalyst at intervals of 45 minutes. After the last addition, the mixture is stirred for a further hour at 85-90 ° C., then 7.5 parts of sodium carbonate, 11.25 parts of 1-aminobenzene-4-sulfonic acid and 1 part of the product obtained according to Example 16 are added. After stirring for 20 hours at 85-90 ° C, 50 parts of sodium chloride are added. The precipitate which precipitates on cooling is filtered off at 25 ° C. The moist filter cake is stirred in 1000 parts of water at 90 ° C. and the solution is filtered after adding 10 parts of a filter aid (diatomaceous earth Hyflo Supercel). 135 parts of sodium chloride are added to the dark blue solution (900 parts) at 75 ° C. while stirring and the mixture is allowed to cool to 35 ° C. while stirring. The precipitated dye is filtered off, washed twice with 15% sodium chloride solution and dried. Taking into account the sodium chloride content, 18.3 parts of the disodium salt of 1-amino-4-anilinoanthraquinone-2,4'-disulfonic acid are obtained as a dark powder. The dye dyes wool from acid baths in blue tones.

Claims (11)

1. A process for the preparation of an electrically conductive filler which comprises pyrolysing a mixture of at least one metal phthalocyanine and at least one inorganic filler.

2. The process according to claim 1, wherein the metal phthalocyanine used is copper, nickel, cobalt or iron phthalocyanine.

3. The process according to claim 1, wherein the metal phthalocyanine used is copper phthalocyanine.

4. The process according to claim 1, wherein the metal phthalocyanine used is the crude β-form of copper phthalocyanine.

5. The process according to claim 1, wherein the inorganic filler used is aluminium oxide, wollastonite, iron oxide, titanium dioxide, mica or quartz.

6. The process according to claim 1, wherein the inorganic filler used is crystalline or amorphous quartz with a particle size of 0.01 to 1,000 µm.

7. The process according to claim 1, wherein the pyrolysis is carried out at temperatures from 650 up to 2,500°C under a pressure of 0.5 to 20 bar in air, an inert gas, in air with an increased oxygen content or in hydrogen gas.

8. The process according to claim 1, wherein the pyrolysis is carried out at 800 to 1,200°C under atmospheric pressure in air.

9. The use of the process according to claim 1 for the preparation of a filler for incorporation into high molecular weight organic material.

10. The use of the process according to claim 1 for the preparation of a filler for incorporation into inorganic material.

11. The use of the process according to claim 1 for the preparation of a filler for incorporation into an epoxy resin.