Patents Assigned to Partek, Inc.
  • Process for recycling polyester
    Patent number: 5395858
    Abstract: A process for recycling polyester contained in waste materials is provided. The polyester is converted into ethylene glycol and terephthalic acid. The process steps generally include first combining materials containing polyester with an alkaline solution to form a slurry. The slurry is heated, causing ethylene glycol to evaporate which can then be collected. The remaining product stream is then mixed with water and filtered to remove any undissolved impurities. The aqueous filtrate can be acidified causing terephthalic acid to precipitate. Further, if silver is contained within the materials fed to the process, the silver can also be isolated and recovered.
    Type: Grant
    Filed: April 28, 1994
    Date of Patent: March 7, 1995
    Assignee: Partek, Inc.
    Inventor: John A. Schwartz, Jr.
  • Composition for removing adhesives from polymeric film and process for using same
    Patent number: 5366998
    Abstract: A novel composition for use in reducing and recovering metals, such as silver, and for use in stripping adhesive polymer layers from various polymer bases, such as polyester, and processes for using same are provided. The composition and variations thereof can be useful in separating an adhesive polymeric layer from the film for recovery of either. The composition comprises a reducing sugar/alkaline solution that is particularly useful for recovering silver from polyester photographic film where a silver halide light-sensitive emulsion layer is adhered to the polyester film by a polymeric adhesive resin, such as resins containing copolymers of polyvinylidene chloride and polyvinyl chloride. Processes for separation and recovery are also disclosed and claimed.
    Type: Grant
    Filed: March 22, 1993
    Date of Patent: November 22, 1994
    Assignee: Partek, Inc.
    Inventor: John A. Schwartz, Jr.
  • Composition for recovering metals and process for using same
    Patent number: 5286463
    Abstract: A novel composition for use in reducing and recovering metals, such as silver, and for use in stripping adhesive polymer layers from various polymer bases, such as polyester, and processes for using same are provided. The composition and variations thereof can be useful in separating an adhesive polymeric layer from the film for recovery of either. The composition comprises a reducing sugar/alkaline solution that is particularly useful for recovering silver from polyester photographic film where a silver halide light-sensitive emulsion layer is adhered to the polyester film by a polymeric adhesive resin, such as resins containing copolymers of polyvinylidene chloride and polyvinyl chloride. Processes for separation and recovery are also disclosed and claimed.
    Type: Grant
    Filed: March 23, 1992
    Date of Patent: February 15, 1994
    Assignee: Partek, Inc.
    Inventor: John A. Schwartz, Jr.