RU2089566C1 - Molding compound and method of preparation thereof - Google Patents

Abstract

FIELD: carbon materials and molding compounds. SUBSTANCE: invention relates to carbon-based molding compounds, in particular, those including thermoplastic polymers. As carbon material, low-toxicity and low-ash disintegrated microgranular carbon material is utilized which has been prepared by way of high-speed (up to 320 m/s) impact disintegration in closed system under inert gas atmosphere. Powder carbon material is chemically bound to thermoplastic hydrocarbon-type polymer (polyethylene and polypropylene). As carbon material, utilized is also anthracite containing more than 94% carbon, less than 2% ashes, less than 2.5% volatiles, and less than 1.5% sulfur. Size of material granules is 10-90 mcm. Carbon material to polymer weight ratio is chosen in the range (20-70):(30-80). The two components of compound are mixed in extruder at 200-300 C under pressure 200 N/sq.mm, carbon material having been preheated to mixing temperature. EFFECT: improved quality of compound. 9 cl, 7 dwg, 2 tbl

Description

 The invention relates to carbon-containing molding materials, and in particular to a molding material based on a carbon material and a thermoplastic polymer, as well as to methods for its preparation.

Known molding mass containing 100 parts of a polyolefin polymer and 100-400 parts of a filler, highly dispersed petroleum coke, which at least 80% has an average particle size of 0.75-50 microns [1]
To obtain the specified molding mass is a method in which the mass is obtained by simply mixing both components in standard mixing devices, after which the mixture is homogenized at about 183-205 ^o C for about 10 minutes, while in the resulting mass, both components are mechanically connected between themselves [1]
However, the known molding material has insufficient strength properties of products obtained from it.

Closest to the technical nature of the invention is a molding composition containing carbon powder material selected from the group consisting of coal, coal coke and petroleum coke with a thermoplastic polymer of the hydrocarbon group [2]
A known method of producing said molding material based on a carbon material and a thermoplastic polymer of a hydrocarbon group, in which a powder carbon material selected from the group consisting of coal, coal coke and petroleum coke is mixed with a thermoplastic polymer of a hydrocarbon group [2]
However, the physical properties, including the strength properties of the known molding material and the products obtained from it, are not satisfactory.

 The technical result of the invention is the development of a molding material based on carbon powder material and a thermoplastic polymer, which allows to obtain products with improved properties.

 To obtain a technical result in a molding material containing carbon powder material selected from the group consisting of coal, coal coke and petroleum coke, and a thermoplastic polymer of the hydrocarbon group, disintegrated micro-granular carbon material obtained from harmful substances and sols is used as the hydrocarbon powder material, obtained by high-speed impact grinding in a closed system in an inert gas atmosphere, and the carbon powder material is chemically It is associated with a thermoplastic polymer of a hydrocarbon group.

 In addition, anthracite of the following composition was used as a disintegrated microgranular carbon material, poor in harmful substances and sols: carbon content> 94% ash content <2% volatile components <2.5% sulfur content <1.5% Disintegrated microgranular carbon material has a value grains of 10-90 microns.

 The disintegrated microgranular carbon material and the thermoplastic polymer of the hydrocarbon group chemically bonded to it are taken in the mass ratio (20-70) :( 30-80).

 As a thermoplastic polymer of the hydrocarbon group, polyethylene or polypropylene is used.

 In the method for producing a molding material based on a hydrocarbon material and a thermoplastic polymer of a hydrocarbon group, in which a powder carbon material selected from the group consisting of coal, coal coke and petroleum coke is mixed with a thermoplastic polymer of a hydrocarbon group, the poor material is used as carbon material substances and sols disintegrated microgranular carbon material obtained by high-speed impact grinding soon up to 320 m / s in a closed system in an inert gas atmosphere.

The mixing of the carbon powder material and the thermoplastic polymer of the hydrocarbon group is carried out in an extruder at 200-300 ^o C, mixing is carried out under a pressure of 200 N / mm ² . Before mixing with the thermoplastic polymer of the hydrocarbon group, the disintegrated microgranular material is heated to the temperature of the mixing process.

 In FIG. 1-7 shows data on the qualitative characteristics of products made of pure polyethylene or polypropylene and products from the described mass.

 The molding material contains carbon powder material and a thermoplastic polymer of a hydrocarbon group. The carbon powder material is selected from the group consisting of coal, coal coke and petroleum coke. Disintegrated microgranular carbon material, poor in harmful substances and sols, was used as carbon powder material. The specified material is obtained by high-speed impact grinding in a closed system in an inert atmosphere. Thanks to high-speed impact grinding at speeds of up to 320 m / s in a closed system in an inert gas atmosphere, a disintegrated microgranular carbon material is obtained, which, when mixed, preferably in an extruder, chemically binds to a thermoplastic polymer of the hydrocarbon group.

 High-speed impact grinding can be carried out in any suitable plants, in particular in vortex disintegrators, which are equipped with rotor blades radially arranged one after the other. During operation, vortex zones are formed in the annular spaces between the blade crowns in which particles of the carbon powder material hit each other at high speeds without causing unwanted metal wear. When passing through vortex zones radially adjacent to each other, each particle of carbon material collides with other particles 8 times on average, moreover, first of all, in the last vortex zone between the penultimate and outer blade corners, but also beyond it there are shock velocities close to the sound velocity . The grinding time in the vortex disintegrator is 0.5 s.

High-speed impact grinding provides excitation energy for hydrogen ions / electrons and carbon electrons, which can occupy free orbits, including orbits of a higher energy level. This process is temperature dependent. Therefore, according to the invention, high-speed impact grinding, as well as mixing of microgranular carbon material and a thermoplastic polymer, in particular polyethylene and polypropylene, is carried out in the extruder with heat supply, which in front of the extruder and in it leads to increased reactivity of the microgranular carbon material. It was found that the best temperature for converting the microgranular carbon material and thermoplastic polymer into the molding material in the extruder is 200-300 ^o C. At temperatures well below the specified lower limit, the desired high quality characteristics of products obtained from the molding material, including good electrical conductivity, are not achieved. The mixing process is carried out under pressure, preferably under a pressure of 200 N / mm ² . The mixing process can also be carried out in an inert gas atmosphere. The inert gas atmosphere used in high speed impact grinding and mixing can contain up to 3% oxygen.

In the case of using anthracite as a carbon material, high-speed impact grinding at almost sound speed leads to a surface change with the formation of pores with diameters of less than 3.6 μm, due to which the surface of the particles is 10 times larger than that of anthracite processed in a ball or vibration mill (screening at 40 microns). The surface achieved with high speed impact grinding is 28 m ² / g compared with a surface of 2.5 m ² / g or 2.8 m ² / g when prepared in a ball or vibration mill. Pores are formed due to the fact that during high-speed impact grinding close to the speed of sound, temperatures of the order of 300 ^° C occur for a short time, due to which the volatile components of anthracite are released. These micropores impart hygroscopicity to anthracite (up to 6% absorption of water, partly from ambient air). The ability of liquids to penetrate into these micropores and to accumulate in them is due to the molecular structure of the corresponding liquid. Hydrogen ions or at least hydrogen dipoles occupy the corresponding places in the pores, so that hydroxyl ions or hydroxyl dipoles can no longer attach to these places (this process is time-dependent). Extending the storage time of anthracite before processing it in an extruder reduces the ability of the molecules to absorb the hydroxyl group. This process plays an important role in mixing the microgranular disintegrated carbon material, preferably the microgranular disintegrated anthracite, with the thermoplastic polymer in the extruder, and therefore it should be taken into account accordingly.

When used as a disintegrated microgranular carbon material, for example, disintegrated microgranular anthracite, in the described molding material, the hydrogen of the CH ₂ -CH ₂ polymer units chemically binds to the carbon units of the -CCC anthracite.

According to the invention, preferably pure polyethylene or polypropylene is preferably used as thermoplastic polymers, which are melted at 240-300 ^° C., for example, in a twin-screw extruder equipped with screws rotating in the same direction. Prepared disintegrated microgranular carbon material is added continuously to the melt in doses, in particular with a grain size of 10-90 microns, which is preferably disintegrated microgranular anthracite heated to 200-300 ^° C. Depending on the type of granulate, the anthracite content varies between 30 and 80 wt. The resulting extrudate is granulated so that there is no reduction in quality during storage. This granulate can then be processed into the desired products, for example, molded products, plates, pipes, films, and thanks to the chemical and UV resistance in containers, tanks, barrels and canisters for the disposal of chemical industry waste and special waste, in almost all known plastic processing plants.

As a disintegrated micrograin hydrocarbon material, anthracite poor in sol and sulfur is particularly suitable as follows:
Carbon content Over 94%
Ash content Less than 3.5%, in particular less than 2%
Sulfur content Less than 1.5%
Volatile components Less than 2.5%
Calorific value More than 35500 kJ / kg
If you mix disintegrated micrograin anthracite of the above composition and polyethylene in a mass ratio of 70:30, you get a molding mass, which allows to obtain a product that, in comparison with a product of pure polyethylene, has the following qualitative characteristic (see table. 1).

 Another important property of the described molded mass is that its calorific value exceeds the calorific value of standard fuels, as evidenced by a comparison of the following data given in Table 2.

 Thus, after repeated recirculation, the molding material can be neutralized without problems with the production of environmentally friendly thermal energy by burning in power plants, in cement plants, for calcining lime, or the like. waste incineration plants costs the customer up to 400 German marks per 1 ton. In contrast, power plants, companies for the production of cement, lime burning, etc. pay the supplier of the proposed molding material for its high calorific value. Due to the high carbon content of up to more than 90%, the spent molding material is of interest to the steel industry, which is interested in improving the quality of steel. Contamination of combustion plants or the content of harmful substances in flue gases in excess of permissible limits do not occur.

 Poor of harmful substances neutralization of the molding material is ensured by the fact that thermoplastics are added to the carbon component, which contain only such substances as additives, stabilizers, electrically conductive substances or pigments. When burning the mass or the product obtained from it, the latter do not emit substances with toxic effects that enter the flue gas or which do not lead to a load of harmful flue gas substances exceeding the permissible limits.

It was found that the mass, which consists, for example, of 70 wt. disintegrated micrograin anthracite and 30 wt. polyethylene, resistant to chemicals at ambient temperatures up to max. 37 ^o C and is resistant to ultraviolet radiation (test time: 2000 h; upper limit of anthracite grains: 60 microns).

 By crosslinking the molding material with an electronic accelerator, it is possible to significantly increase the strength and heat resistance of products obtained from it, for example pipes, containers, barrels, molded products, etc. However, the thermoplastic properties are constantly reduced as the degree of crosslinking increases. Masses having a high degree of crosslinking are no longer suitable for recycling, but at the same time they do not lose their advantages with respect to the neutralization of fuel with a high calorific value that is not harmful to the environment and harmful to harmful substances.

 The attached graphs (Fig.1-7) explain the essential properties of the proposed molding material.

 In FIG. 1 it can be seen how the tensile strength (stress at the tensile strength) of the molding material increases with an increase in the content of anthracite having grains of 60 μm. Based on pure polyethylene (PE; 100%). In this case, anthracite has the composition specified in paragraph 2 of the claims. The decrease in the size of the grains of anthracite leads only to a slight increase in tensile strength or tensile.

Figure 2 presents the dependence of the increase in strength of the described molding mass on the content of anthracite in it. Pure polyethylene (PE) with a strength of 25.2 N / mm ² and pure polypropylene (PP) with a strength of 32.6 N / mm ^{2 are} taken as the basis. And in this case, anthracite has a grain size of 60 microns. It is interesting that the mass with the addition of polyethylene has a significantly increased tensile strength than the mass that contains polypropylene as a thermoplastic polymer. Obviously, the reaction of anthracite prepared according to the invention with polyethylene is more durable than its reaction with polypropylene. With both masses, the tensile strength increases in different ways as the content of anthracite in them increases.

 Figure 3 presents the dependence of the toughness of the molding material on the size of the grains of anthracite and its content in it. When the grain size of micrograin anthracite is 90 μm, the toughness of the mass is completely preserved until the anthracite content is 30%. With an increase in the anthracite content, it decreases and when the anthracite content is 60%, the toughness is only 20%. A similar picture is obtained in the case of the described molding mass, which contains disintegrated micrograin anthracite with grain sizes of 60 μm, 30 μm and 10 μm, respectively. Therefore, if the molding composition with a high content of anthracite must have a high impact strength, it is recommended to use anthracite with a smaller grain size.

 In FIG. 4 shows that the toughness of the molding material does not change as a result of atmospheric exposure. In contrast, polyethylene becomes brittle after 250 hours. This lack of polyethylene is usually compensated by the addition of stabilizers. The described mass does not need such additives.

 In FIG. Figure 5 shows the effect of the anthracite content on electrical conductivity, which, when the anthracite content is 60%, reaches a maximum (which corresponds to a minimum of surface resistance).

 Figure 6 shows that even after repeated recycling, the molding material almost completely retains its tensile strength. Elongation in tension increases. Only after the third mass recirculation does the impact strength drop to 50%. With each recirculation, the impact strength, which is determined on the notched specimen, also decreases. But for many products, both indicators are quite sufficient after five times recycling. The softening point is only slightly reduced. Regardless of the recirculation number, the described mass retains its high calorific value.

As can be seen in Fig.7, the content of anthracite also affects the softening temperature of the described molding material. Based on the softening temperature of pure polyethylene (78 ^o C), which is taken as 100%, the softening temperature of the described mass with anthracite content with a grain size of 60 μm equal to 70% is approximately 107 ^o C; those. it is about 37% higher than the softening temperature of pure polyethylene.

Claims (8)

 1. Molding mass containing carbon powder material selected from the group consisting of coal, coal coke and petroleum coke, and a thermoplastic polymer of the hydrocarbon group, characterized in that the disintegrated micro-grain carbon material poor in harmful substances and sols is used as the carbon powder material, obtained by high speed impact grinding in a closed system in an inert gas atmosphere, and the carbon powder material is chemically bonded to thermo rib polymer hydrocarbon group. 2. The mass according to claim 1, characterized in that as the disintegrated microgranular carbon material, poor in harmful substances and sol, anthracite of the following composition is used,
Carbon 94
Ash content <2
Volatile components <2.5
Sulfur <1.5
3. The mass according to claims 1 and 2, characterized in that the disintegrated microgranular carbon material has a grain size of 10 to 90 microns.  4. The mass according to claims 1 to 3, characterized in that the disintegrated microgranular carbon material and the thermoplastic polymer of the hydrocarbon group chemically bonded to it are taken in a weight ratio of 20-70 30-80.  5. The mass according to claims 1 to 4, characterized in that polyethylene or polypropylene is used as the thermoplastic polymer of the hydrocarbon group.  6. A method of obtaining a molding material based on a carbon material and a thermoplastic polymer of a hydrocarbon group, in which a powder carbon material selected from the group consisting of coal, coal coke and petroleum coke is mixed with a thermoplastic polymer of a hydrocarbon group, characterized in that as carbon powder material use poor disintegrated microgranular carbon material obtained by high-speed grinding at a speed of up to 320 m / s in a closed system in an inert gas atmosphere. 7. The method according to claim 6, characterized in that the mixing of the carbon powder material and the thermoplastic polymer of the hydrocarbon group is carried out in an extruder at 200 300 ^o C. 8. The method according to claim 7, characterized in that the mixing is carried out under a pressure of 200 N / mm ² .  9. The method according to PP.6 to 8, characterized in that before mixing with a thermoplastic polymer of the hydrocarbon group, the disintegrated microgranular carbon material is heated to the temperature of the mixing process.

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