Method of Decreasing Acetaldehyde Level in a Molded Article

Abstract

There is provided a method for decreasing acetaldehyde level in a molded article. The method of decreasing acetaldehyde content in a molded article to be produced comprises introducing into a feed throat of an injection unit a PET material to be plasticized, the PET material having been dried in a pre-treatment chamber ; and introducing into the feed throat an un-treated agent configured to increase moisture level of the PET material to be plasticized. In some embodiments of the present invention, the un-treated agent is also configured to provide additional lubrication to the plasticizing screw.

1 . A method of decreasing acetaldehyde content in a molded article to be produced, the method comprising:
 introducing into a feed throat of an injection unit PET material to be plasticized, the PET material having been dried in a pre-treatment chamber;   introducing into the feed throat an un-treated agent configured to increase moisture level of the PET material to be plasticized.   
   
   
       2 . The method of  claim 1 , wherein said un-treated agent has one of an amorphous structure and semi-crystalline structure. 
   
   
       3 . The method of  claim 2 , wherein said un-treated agent is further configured to provide additional lubrication to a plasticizing screw of the injection unit. 
   
   
       4 . The method of  claim 1 , wherein said introducing comprises introducing said un-treated agent into said feed throat and allowing said un-treated agent to mix with the PET material during practicing. 
   
   
       5 . The method of  claim 1 , wherein said introducing comprises introducing said un-treated agent into a pre-mixer for mixing said un-treated agent with the PET material. 
   
   
       6 . The method of  claim 1 , wherein said un-treated agent comprises un-treated PET material. 
   
   
       7 . The method of  claim 1 , wherein said un-treated agent comprises re-pelletized re-cycled PET. 
   
   
       8 . The method of  claim 1 , wherein said un-treated agent comprises post-consumer recycled PET flakes. 
   
   
       9 . The method of  claim 1 , wherein said un-treated agent comprises PET preform re-grind. 
   
   
       10 . The method of  claim 1 , wherein said un-treated agent comprises PET bottle re-grind. 
   
   
       11 . The method of  claim 1 , wherein said un-treated agent comprises PET scrap re-grind. 
   
   
       12 . The method of  claim 1 , wherein said un-treated agent comprises a combination agent. 
   
   
       13 . The method of  claim 1 , further comprising, prior to said introducing, subjecting the PET material to a pre-treatment process in the pre-treatment chamber. 
   
   
       14 . An injection unit, comprising:
 an inlet having a feed throat for accepting, in use, PET material that has been dried in a pre-treatment chamber;   a plasticizing sub-system for plasticizing the PET material into plasticized material;   an outlet for outputting the plasticized material;   the inlet being associated with a dosing unit, the dosing unit being operatively coupled to a source of an un-treated agent, the dosing unit being configured to introduce into the feed throat the un-treated agent configured to increase moisture level of the PET material to be plasticized.   
   
   
       15 . The injection unit of  claim 14 , wherein said un-treated agent has one of an amorphous structure and a semi-crystalline structure. 
   
   
       16 . The injection unit of  claim 14 , the plasticizing sub-system further including a plasticizing screw operatively mounted within a barrel, wherein the un-treated agent is further configured to provide additional lubrication to the plasticizing screw. 
   
   
       17 . The injection unit of  claim 14 , wherein said un-treated agent comprises un-treated PET material. 
   
   
       18 . The injection unit of  claim 14 , wherein said un-treated agent comprises re-pelletized re-cycled PET. 
   
   
       19 . The injection unit of  claim 14 , wherein said un-treated agent comprises post-consumer recycled PET flakes. 
   
   
       20 . The injection unit of  claim 14 , wherein said un-treated agent comprises PET preform re-grind. 
   
   
       21 . The injection unit of  claim 14 , wherein said un-treated agent comprises PET bottle re-grind. 
   
   
       22 . The injection unit of  claim 14 , wherein said un-treated agent comprises PET scrap re-grind. 
   
   
       23 . The injection unit of  claim 14 , wherein said un-treated agent comprises a combination agent. 
   
   
       24 . The injection unit of  claim 14 , further comprising the pre-treatment chamber. 
   
   
       25 . The injection unit of  claim 14 , wherein the dosing unit is configured to introduce the un-treated agent directly into the feed throat, whereby the un-treated agent is mixed with the PET material during plasticizing. 
   
   
       26 . The injection unit of  claim 14 , further comprising a pre-mixer operatively coupled in series between the pre-treatment chamber and the feed throat, the dosing unit is configured to introduce the un-treated agent into the pre-mixer; whereby the un-treated agent is mixed with the PET material prior to introduction to the feed throat. 
   
   
       27 . A method of decreasing acetaldehyde content in a molded article to be produced, the method comprising:
 introducing into a feed throat of an injection unit a PET material to be plasticized, the PET material having been dried in a pre-treatment chamber;   introducing into the feed throat an un-treated agent, the un-treated agent having one of an amorphous structure and a semi-crystalline structure, the un-treated agent configured to increase moisture level of the PET material to be plasticized and to provide additional lubrication to a plasticizing screw of the injection unit.   
   
   
       28 . A method of decreasing acetaldehyde content in a molded article to be produced, the method comprising:
 introducing into a feed throat of an injection unit a PET material to be plasticized, the PET material having been dried in a pre-treatment chamber;   introducing into the feed throat an un-treated agent, the un-treated agent selected from a list including:
 un-treated PET material; 
 re-pelletized re-cycled PET, 
 post-consumer recycled PET flakes, 
   2 PET preform re-grind, 
 PET bottle re-grind, 
 PET scrap re-grind, and 
 a combination of at least some thereof. 
   
   
   
       29 . A method of decreasing acetaldehyde content in a molded article to be produced, the method comprising:
 introducing into a feed throat of an injection unit molding raw material to be plasticized, the molding raw material having been dried in a pre-treatment chamber;   introducing into the feed throat an un-treated agent configured to increase moisture level of the molding raw material to be plasticized.   
   
   
       30 . The method of  claim 29 , wherein said un-treated agent comprises un-treated molding raw material or an un-treated derivative thereof. 
   
   
       31 . An injection unit, comprising:
 an inlet having a feed throat, the inlet being operatively connectable, in use, to a pre-treatment chamber to accept PET material having been dried in the pre-treatment chamber and to a source of an un-treated PET material via a dosing unit;   a plasticizing sub-system for plasticizing the PET material and the un-treated PET material into plasticized material;   an outlet for outputting the plasticized material;   the dosing unit being configured to introduce into the feed throat an amount of the un-treated PET material, thereby to at least decrease content of acetaldehyde produced during plasticizing.