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Process and apparatus for pelletization of polymers

A technology of polymers and molten polymers, applied in the direction of raw material extrusion granulation, etc., can solve problems such as process abnormalities and difficulty in starting

Inactive Publication Date: 2008-11-19
TICONA LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, UMC has many disadvantages, including difficult to granulate TP with a high melting point (>200°C) or TP that is easy to freeze into a solid on the contrary, it is not suitable for process abnormalities, such as short-term interruption of polymer flow, and sometimes it is difficult to start.

Method used

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  • Process and apparatus for pelletization of polymers
  • Process and apparatus for pelletization of polymers
  • Process and apparatus for pelletization of polymers

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～6

[0068] In these examples, each polymer formulation was underwater pelletized using Die A with 8 die holes. In all cases, the die holes had a 2° reverse taper. The polymer is fed to a die using an extruder that melts the polymer composition. The melt temperature of the polymer in the extruder is maintained at (or above) the temperature recommended by the polymer manufacturer. At some point the flow of the polymer is interrupted and it is allowed to freeze at the exit end of the die orifice. Then restart the melt cutting machine (assuming that there is already a polymer in it), by connecting the cutting car (including the knife and cooling water), starting the knife and cooling water circulation, and raising the temperature of the die to near the melting point of the polymer. Start the polymer feed extruder and begin to feed polymer into the extruder, set the reverse valve on the outlet end of the polymer feed extruder that has been set so that the molten polymer does not ente...

Embodiment 7

[0072] A 50-hole industrial underwater melt cutter die with an inverted cone die hole is used. The die body is made of carbon steel and the die body is heated with an electric resistance heater. The holes are assembled so that each hole receives two hole liners. At the inlet face (similar to 42 in Figure 3a) is a straight hole liner 3.58 cm (1.41 inches) long and 3.00 mm (0.118 inches) in diameter, called the inlet section. Immediately downstream (polymer flow) from this inlet section is an outlet section 2.53 cm (0.995 inches) long with a circular orifice diameter of 4.06 mm (0.160 inches). The outlet end of the outlet section is flush with an outlet face (similar to 43 in Figure 3a) and is exposed to the cooling water of the granulator. The exit section can be changed, the hole is straight or has an inverted taper. Inverted taper, if present, may be formed by reaming a straight hole to the desired taper angle extending from the exit face to a depth of 6.35 mm (0.25 in). ...

Embodiment 8-10

[0078]In these examples, Die B with 2 die holes was used to underwater pelletize various polymer formulations. In all cases, the back taper of the die holes was 3° and the melt cutter cooling water temperature was 53°C. The polymer is fed to a die using an extruder that melts the polymer composition. At some point the polymer flow is interrupted and the polymer is allowed to freeze at the exit end of the die orifice. Then restart (assuming there is already polymer in it) the melt cutting machine by connecting the cutting car (including knife and cooling water), starting the knife and cooling water circulation, and raising the mold temperature to the set temperature. Start the polymer feeding extruder and begin feeding polymer to the extruder. Set polymer feed The diverter valve on the extruder end has been set to keep molten polymer out of the pelletizer, feed molten polymer to the pelletizer (die) and start pelletizing at this point. In some cases, when starting polymer fe...

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Abstract

An improved process for the pelletization of polymers is disclosed, using a die in which the die holes incorporate a reverse taper along at least a portion of the length thereof. Conditions for operation of an under melt cutter incorporating this die are also disclosed. The die plate (1) has an exit face (2), where the polymer (not shown) exists the die (hole), and an entrance face (3) where the (molten) polymer enters the die hole (4). In this particular instance, (4) is straight over part of its length, zone 5, and has a reverse taper over part of its length, zone 6. The tapered portion has a 'taper angle' (8).

Description

field of invention [0001] The present invention relates to the start-up of underwater melt pelletizers or cutters. More particularly, the present invention relates to a method for easy and quick start-up of such pelletizers and cutters using a die having a die hole having an inverted taper on the die exit side. The invention also relates to an improved die assembly design for an underwater melt cutter. Background of the invention [0002] Thermoplastics (TP) are very important industrial products. They are generally formed into various parts or shapes by melt forming, ie melting the TP, forming it into a shape while it is molten, and then allowing the TP to cool into a solid to "fix" it in that shape. In most melt formers, TP is fed as pellets or granules, generally in the size range of 0.1 to about 0.7 cm (largest dimension). For most melt formers to operate efficiently, it is preferred that the pellets or granules are free flowing and of fairly uniform size. [0003] A...

Claims

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Application Information

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IPC IPC(8): B29B9/06B01J2/20B29C47/30B29C48/345
CPCB29B7/823B29B7/826B29B7/582B29B9/065
Inventor R·A·杰克逊D·J·罗耶M·G·沃戈纳
Owner TICONA LLC