Extrusion pelletizer for polycarbonate resin and method for extrusion-pelletizing polycarbonate resin

Patent metadata

Field	Value
Publication number	US-10464235-B2
Application number	US-201314765450-A
Country	US
Kind code	B2
Filing date	Dec 25, 2013
Priority date	Feb 4, 2013
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

An extrusion pelletizer for a polycarbonate resin includes: an extruder; a cooling unit; and a cutter. The extruder includes a cylinder top, a first adapter, a polymer filter unit, a second adapter, and a die head. The polymer filter unit includes a plurality of stick-shaped filter elements therein. A temperature of the second adapter is set to be lower than a temperature of the polymer filter unit. The cooling unit and the cutter are disposed under an atmosphere in which air cleanliness defined in accordance with JIS B 9920 is any one of class 1 to class 7.

First claim

The invention claimed is:

1. A method of extrusion-pelletizing a polycarbonate resin, the method comprising extrusion-pelletizing a polycarbonate resin with an extrusion pelletizer comprising:
an extruder comprising a first adapter that is provided at a cylinder top and is capable of controlling a temperature, a polymer filter unit that is directly connected to the cylinder top through the first adapter and is capable of controlling a temperature, a second adapter that is capable of controlling a temperature, and a die head that is connected to the polymer filter unit through the second adapter;
a cooling unit; and
a cutter,
wherein the extrusion-pelletizing comprises:
extruding a molten polymer to deliver the molten polymer into the polymer filter unit through the first adapter, while controlling the temperature of the first adapter;
filtering the molten polymer delivered into the polymer filter unit, to obtain a filtered polymer;
extruding the filtered polymer from the die head through the second adapter, to obtain an extruded polymer;
cooling the extruded polymer to form a strand; and
cutting the strand with the cutter to pelletize the strand,

wherein:
the polymer filter unit comprises a plurality of stick-shaped filter elements each having a filtration rating of from 5 μm and 50 μm;
the stick-shaped filter elements each comprise:
a lateral surface as a filtering area through which the polycarbonate resin is filtered,
a hollow portion through which the polycarbonate resin filtered by the filtering area flows, and
a discharge portion defining an end of the filter element and through which the polycarbonate resin from the hollow portion is discharged;
the cooling unit and the cutter are disposed under an atmosphere in which an air cleanliness defined in accordance with JIS B 9920 is any one of class 1 to class 7; and
the controlling of the temperature of the second adapter includes lowering the temperature of the second adapter such that the temperature of the second adapter is lower than a temperature of the polymer filter unit by 10 degrees C. or more.

2. The method according to claim 1 , wherein each of the first adapter and the second adapter comprises two or more metallic plates.

3. The method according to claim 1 , wherein the first adapter comprises a plurality of units in order to adjust a shape of a resin outlet in a stepwise manner.

4. The method according to claim 1 , wherein the first adapter comprises an oil-temperature control circuit and a cartridge heater.

5. The method according to claim 1 , wherein the plurality of stick-shaped filter elements includes a candle-shaped filter.

6. The method according to claim 1 , wherein the filtration rating of the stick-shaped filter elements is from 10 μm to 30 μm.

7. The method according to claim 1 , wherein the second adapter comprises a plurality of units in order to adjust a shape of a resin outlet in a stepwise manner.

8. The method according to claim 1 , wherein the second adapter comprises an oil-temperature control circuit and a cartridge heater.

9. The method according to claim 1 , wherein a temperature of the molten polymer delivered into the polymer filter unit is 290 degrees C. or less.

10. The method according to claim 1 , wherein the controlling of the temperature of the second adapter includes lowering the temperature of the second adapter such that the temperature of the second adapter is lower than a temperature of the polymer filter unit by 20 degrees C. or more.

11. The method according to claim 1 , wherein the extruder is a biaxial extruder.

Assignees

• Idemitsu Kosan Co

Inventors

• Watanabe Nobuhiro
• Tanaka Takayoshi

Classifications

• B29K2069/00

  Use of PC, i.e. polycarbonates {or derivatives thereof}, as moulding material · CPC title

• B01D35/18

  Heating or cooling the filters · CPC title

• B29B9/06 Primary

  in the form of filamentary material, e.g. combined with extrusion · CPC title

• B29C48/87

  Cooling · CPC title

• B29C48/0022

  combined with cutting · CPC title