DE2116417A1 - Carbon mouldings - by moulding mixt of carbon and elastomer under pressure at 100-250c - Google Patents

Abstract

Carbon mouldings are produced by mixing C with 10-30wt.% elastomer in powdered, emulsified or dissolved form, and moulding the mixt. at 100-250 degrees C under press. The moulding mixt. may also contain 1-10wt.% of another polymer, 0.5-3wt.% S, 5-40wt.% inert fibrous material and 2-7, pref. 4-5wt.% plasticiser.

Description

Process for the production of shaped bodies from coal The invention relates to a process for the production of molded bodies, for example panels, Profiles, pipes, hoses or foils made of hard coal.

The possibility of processing carbon like plastic masses into pressed bodies, is already by F. Fischer, 0. Horn and H. Küster in the journal fuel chemistry 15 (1934), So 327, on brown coal. From a work by C. Kröger and G. Brinkmann in the journal "Fuel-Chemistry" Vol. 48 (1967), Issue 6, pp. 173-184 and booklet 7, pp. 198-206, it emerges that the binding force of pure coals is too low to produce usable moldings in spite of pressing at high temperatures to get. The cooled moldings do not have sufficient strengths, this applies to both the tensile strength and the flexural strength of the body. For example, those with a coal mine are volatile with 32 Vo Components achieved maximum compressive strengths of 600 to 800 kp / cm2, the associated However, flexural strengths are extremely low.

It has also been proposed to modify the coal in such a way that that they can be processed into moldings like plastic masses. To this Purpose should be the coal 3-15% by weight of modifier added and / or their functional groups by oxidative or chlorinating treatment are increased, or should be pressed as at an elevated temperature. As such Modifying agents should in particular be polyfunctional alcohols and aldehydes, Polyvalent and aromatic amines, dienes and heterocycles are used. Polymers too and rubber are claimed as modifiers.

These molding compounds usually require molding temperatures of over 250 ° C. The compressive strengths that can be achieved are up to 1400 kp / cm², the associated ones Flexural strengths up to 200 kp / cm².

These values are insufficient for many technical purposes. A processing on extrusion presses or extruders is also not possible with these masses.

The invention is based on the object of providing molded bodies made of hard coal of higher compressive strength and flexural strength at relatively low press temperatures 250 ° C to generate.

This object is achieved according to the invention in that the hard coals about 15-30% by weight of polymers or elastomers in powdered, emulsified or dissolved form Form can be added as a modifier and the mixture is known per se Way is deformed at elevated temperature under pressure. Appropriately is the coal was ground to below 100 µ beforehand.

In detail, for example, the following substances come as additives in question; Nylon, perlon, polyethylene, polypropylene, polyvinyl chloride, polytetrafluoroethylene, Copolymers of ethylene and propylene, polyurethanes, natural rubber, polymers of Butadiene and isoprene together with styrene, acrylonitrile or the like, polymers and Copolymers of 2-chlorobutadiene.

The polymers or elastomers are used in the finely ground coal distributed as homogeneously as possible. Here, the polymers or elastomers can be powdered Form at room temperature for 10 - 15 bin homogeneously mixed with the coal will However, the polymers can also be dissolved or emulsified Form of the coal can be added. The latter mode of operation is particularly useful for all natural or synthetic rubber types attached, the rubber actices bit the coal can be mixed. The water of the emulsion can either through Dry up or weir and the processing can be removed by ventilation. Possibly then it is re-ground to a grain size below about 1 na.

The mixture obtained can, surprisingly, be used with all Tools such as die or extrusion presses, extruders or injection molding machines are well processed.

Optionally, to further improve the processability bituminous substances such as tar for up to approx. 10 s to the mixtures before deformation, Tar products, pitch and / or bitumens of other origins, such as petroleum bitumen, added will.

The processing of the mixtures can be carried out with the aforementioned works take place at the relatively low temperatures between about 100 and 250 ° C. It it is advisable to relax briefly during the pressing process, ui unhindered Allow released gases to escape.

A further increase in the flexural and tensile strength of the porn body by about 30% occurs if the mixture is 5 - 40% by weight inert, fibrous materials are added. Such substances are, for example, asbestos, Glass wool, carbon fibers or similar are suitable. These mixtures can also be used both on presses as well as in extruders and injection molding machines such as pure thermoplastic Process fabrics.

The moldings obtained are characterized by particularly high mechanical properties as well as very favorable thermal and electrical properties.

Example 1 80 parts by weight of a gas flame coal (Baldur Flöz Hagen) with 38.7% Volatile Ingredients wf, 2.8% Axis wf and 1.5% water are on ground to a grain size below 100 µ and emulsified with @@ parts by weight in water Butadiene-acrylonitrile copolymer and parts by weight of sulfur Homogeneous at room temperature mixed.

400 g of this mixture are put into a punch press preheated to 210 ° C filled in and deformed within 6 minutes according to the following program: a) 1. and 2. Minute with a pressure of 250 kp / cm2, then about 5 - 10 seconds ventilation, b) 3rd and 4th minute with a pressure of 500 kp / cm², then about 5-10 Seconds ventilation, c) 5th and 6th minute with a pressure of 500 kp / cm2, then Ejection of the molding from the hot press tool at 210 ° C.

The plates obtained have a size of approximately 200 mm × 200 mm x 8 mm the following mechanical, thermal and electrical characteristics: 1) resistance to jolting: = 2000 kp / cm2 Flexural strength: = 250 kp / cm² E-module: E = 10,000 - 15,000 kp / cm2 Shore hardness: 90 - 95 Apparent density: = 1.3 g / cm3 Thermal conductivity: - 0.37 kcal / m h degree DC conductivity: = 2. 10-14 (Ohm. Cm) -1 dielectric constant real part: = 7.5 - 5.5 (at 800 - 106Hz) Loss angle: = 0.07 - 0.06 (at 800 - 106Hz) example 2 70 parts by weight of the gas flame coal mentioned in Example 1 are reduced to one grain size ground below 100 / u and mixed with 20 parts by weight of powdered butadiene-acrylonitrile copolymer and 10 parts by weight coal tar mixed until a free-flowing mixture with a average grain size of about 1 mm.

This mixture is poured into an extruder and plasticized. The extruder has 3-zone heating with the following temperature levels: 1. Stage (feed zone) 1200C, 2nd stage (middle area) 1500C, 3rd stage (nozzle head) 120 ° C.

The temperature of the wet is 120 ° C at the nozzle head at one speed of 30 rpm is obtained with a screw 19 mm in diameter and 380 mm in length with a thread depth of 1: 1 an output of about 20 g / min. The resulting torque is 3.7 mkp. When using a screw with compression (thread depth 1: 2) the output can be increased to about 25 g / min.

Depending on the type of nozzle head, endless round strands of the most varied Diameters or foils of different thicknesses can be produced. Using a round hole nozzle with a diameter of 6 mm is obtained, for example, from the described Mixture of very flexible round strings with a tensile strength of = 0.9 kp / mm2 Example 3 A mixture consisting of 70% gas flame charcoal, 20% butadiene acrylonitrile copolymer and 10% polyvinyl chloride or polypropylene or polyethylene or another Polymer as a free-flowing mixture, e.g. in powder or granulate form, into a 3-zone heated extruder (D = 19 mm, L = 38V mm, screw compression 1: 3) filled in and extruded. The heating zones are set to the following temperatures: 1st zone 160 - 1900C, 2nd zone 180 - 210 ° C, 3rd zone 150 - 170 ° C.

It can, depending on the nozzle shape used, endless round strands, pipes or profile bodies of any kind can be produced.

Example 4 If a mixture consisting of 70% gas flame coal is produced, 10 ffi butadiene acrylonitrile copolymer and 20% of one of those listed in Example 3 Polymers, the extruded moldings lose some of their elasticity, on the other hand, however, the toughness (e.g. impact strength, flexural strength) can be increased, which - depending on the type of application of the product - is often desirable.

Claims (6)

Claims 1) Process sur production of molded bodies from hard coal, thereby characterized in that the bituminous coals have about 15-30% by weight of polymers and / or elastomers Added in powdered, emulsified or dissolved form as a modifying agent are and the mixture in a known manner at elevated temperature below Pressure is deformed. 2) Method according to claim 1, characterized in that the coal before mixing with the polymers and elastomers to grain sizes below 100µ be called out. 3) Method according to claims 1 and 2, characterized in that that up to about 10% by weight of bituminous substances are added to the mixture before the deformation will. 4) Method according to claims 1 to 3, characterized in that that the mixture of coal, polymers and optionally bituminous substances Temperatures 9; between about 100 and 2500 C is deformed. 5) Process according to claims 1 to X, characterized in that that the mixture 5 - 40 wt .-% inert, fibrous materials sugesetst. 6) Process according to claims 1 to 5, characterized in that that in mixtures with unsaturated macromoleculars, 0-3% sulfur was added will.