DE2247148A1 - DEVICE FOR THE PRODUCTION OF THERMOPLASTIC PLASTIC GRANULES - Google Patents

Description

contraption
for the production of thermoplastic plastic granulate

The invention: relates to a device for producing thermoplastic plastic granulate with an injection mold, which is suitable for cutting the extruded threads or strands under water and with a metallic one Nozzle plate is equipped, which a plurality of pipe bodies inserted into openings in the nozzle plate for Extruding thermoplastic plastic starting material, and relates in particular to the nozzle plate, ■ at the end face of the emerging thermoplastic polymer-plastic threads or strands under water Granulutteilchen be cut off.

Polymer granules may be prepared in such a manner that the extruded mun Pol.yinor example, thread, strip barren strand form, and this named after the cooling and drying in eüiur Grv-nulatschneidvorrichtung also granulator · to granules t particle cutoff t.

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BATH ORIGINAL

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Another possibility for the production of polymer granules is to use the in a preferred extrusion process Cool the extruded polymer and cut it into granulate particles under water. This for technical representation The method used suffers from certain disadvantages, namely, solidification or solidification often occurs of the polymer in the injection mold openings, resulting in oversized Pressure in the system, for the formation of granules with irregular Shape and leads to an excessive proportion of very small granules or rods. Also arise with known methods or techniques often difficulties in starting production, since to achieve a perfect Start-up the water cooling, the supply or task of the polymer and the rotary motion of the cutting knife in complete must be done with the same rhythm.

The invention is based on the tasks with simple means to create an economically manufacturable device with which the demands made in the manufacture of thermoplastic plastic granulate in a particularly reliable manner Way to be fulfilled.

This object is achieved by a device which, according to the invention, is characterized in that for improvement; the Heat supply to the luetall of the nozzle plate each of the in the Nozzle plate inserted Kohrkörper from a connecting Cavity for the passage of a heat exchange flux around- ': is closed, and that to reduce deö heat loss on the face of the metal nozzle plate inserted hearing element on the face of the nozzle plate are encased by insulating members.

The invention is explained below with further details on the basis of schematic drawings of an exemplary embodiment. In dor drawing zr Lgt:

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i'ig. 1 shows a section through a nozzle plate in accordance with the invention education,

2 shows a section through part of a Nozzle plate,

. "· · A section, on an enlarged scale, through a Part of the nozzle plate according to Fig. 1, and

4 a block picture, partly in section, of a plant for producing plastic granules using the device according to the invention.

Fig. 1 shows a simplified section through eiue injection mold, which has a water vapor inlet 1, an annular water vapor. leanal 2, an EeramiltbeSchichtung 3 * inserted body 4 _t a sons surface 5 i «ad has a« water vapor outlet cone 6. ·

The one connecting and continuous liöhluiig and in fig. 1 in its entirety with 2 tjezjeißhßgt © ring-shaped ©!, 'AsserdampfkaiTisl is arranged relatively to the front in the injection molds -' th Holirlikörperei'n so that with Kiiidtirchleiteia ven heat exchange fluid _f, for example, νοκ water vapor from heated oil, a maximum is with the metal of Sprit2form held _t woäureh the pritzf ^ rm & atxf a temperature kept _t sufficient vm _t solidification to prevent the melted polymer *.

The volume or the measurements of the annular water vapor channel or the cavity can vary depending on the size of the injection mold and the for the nozzle plate or for the in ^! the tubes used by the Tritzfoxm; lletalltyp very untersehiedlieh.sein "However, the effective Öberflache aes ring ·.} Wasserdampiiianals preferably" as big gnviäfölt>

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that between the heat exchange fluid and the metal of the nozzle plate, a maximum heat exchange can be achieved in a short time that is, increases of up to $ 100 are achievable.

Any metal, alloy or similar compound can be used as the metallic material for the nozzle plate, such as steel.

The tubular bodies used in the injection mold for extruding the polymer are made of tough, wear-resistant material, made of tungsten carbide steel, for example, and penetrate the nozzle plate (Fig. 1).

As can be seen from FIGS. 1 and 3, the nozzle plate is around , each of the tubular bodies inserted into them an insulating material applied or otherwise attached. The insulating material or the insulating member is preferably an annular one Ceramic plate or ceramic coating. However, they are arbitrary other types of insulation material can be used. The coating or insulating material is to achieve a smooth cutting surface with the mouths of the one inserted into the SpritEform Tube body ground flush. The thickness of the leoliermateriala can be different, but a material thickness between 1.5 and 2.5 mm has proven to be advantageous.

The special spatial arrangement of the embedded pipe bodies in the nozzle plate differs in that the cutting knives in each position of one or more of the tubular body inserted into the injection mold are "supported". In this way there is wear and tear on the more delicate looliorni material, for example ceramics »avoided.

To describe the working steps of the extruder and the Please refer to the representation in Pig. 4 referenced, after which molten polymer through an extruder θ and a Perforated or baffle plate 9 flows. An injection mold 11 is with

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inserted nozzles and an annular channel for the passage equipped with water vapor 10. Extruded polymer is water cooled in devices 12, 17 and 19 and cut in a plan cutting chamber 15 with rotating knives 14 driven by a drive 13. The polymer granulate particles arrive at a precautioner 16 equipped with sieves 18, and from there via a rotary dryer finally in a storage container 21.

With the device according to the invention is thermoplastic Polymer granulate, for example made from polyethylene, polypropylene, from their copolymers, from polystyrene, A.B.S. copolymers and from block copolymers of acrylonitrile and styrene manufacturable. .

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Claims (3)

8 MUNICH OO \ j - 'SCHWEIGERSTHASSE 3 m TELEPHONE (0811) 662091 TKI. KX 3 24 070 KLKOIlAMMiSI / £ Δ / I Δ Q HOTECTPATKWT MUWCHBN 1A-42 006 CLAIMS 1. Apparatus for producing thermoplastic Plastic granules with an injection mold that can be used for cutting flat of the extruded threads or strands under water and equipped with a metallic nozzle plate which is a plurality of pipe bodies inserted into openings of the nozzle plate for extruding thermoplastic Has plastic starting material, characterized in that to improve the heat supply to the Metal of the nozzle plate each of the tubular bodies (4) inserted into the nozzle plate from a connecting cavity (2) enclosed for the passage of a heat exchange fluid (10) is, and that to reduce the heat loss at the End face (5) of the metallic nozzle plate in this inserted tubular body (4) on the end face (5) of the nozzle plate are encased by insulating members (3). 2. Apparatus according to claim 1, characterized in that the insulating member (3) used has a Ceramic coating is. / 7 309814/1094 3. A device according to claim 1 or 2, characterized GEK e η η is characterized in that the hollow body / inserted into the injection mold {4) are made of Wolframcarbidstahl. 4, Vorrichtmif: according to one of claims 1 to 3> characterized geke η η ζ η et verifiable that the insulating coating used (3) mm has a thickness between 1.5 and 2.5, 3 0 9014 / 109A Blank page