Patent ID: 9539752
Date: 2017-01-10
CPC Classifications: B29C,B29K,C06B,C08B,C08L,D01F,D10B,Y02P

Claim:
1. A continuous extrusion process for producing a celluloid article comprising the steps of: providing a quantity of nitrocellulose; providing a quantity of camphor; providing an extruder defining a chamber, an opening for receiving materials into said chamber, at least two screws for mixing material in said chamber, and an extrusion die coupled to said chamber for extruding material located in said chamber; said chamber comprising a first zone, a second zone, a third zone and a devolatilization zone; introducing the nitrocellulose into said first zone of said chamber; dissolving said camphor in a low boiling point solvent selected from the group consisting of: methanol, ethanol, acetone, and mixtures thereof, to form a camphor solution, and introducing said camphor solution into said first zone or said second zone of said chamber; adding an additional solvent to said first zone or said second zone; transporting the nitrocellulose into said second zone of said chamber; continuously mixing said nitrocellulose, camphor solution, and additional solvent in said second zone to form a mixture; transporting said mixture to said third zone of said chamber and further continuously mixing said mixture at a higher temperature relative to a temperature of said first zone; transporting said mixture to said devolatilization zone and extracting a first amount of both the low boiling point and additional solvents from the mixture in said devolatilization zone by heating the mixture to a devolatilization temperature that is above the normal, atmospheric boiling points of both said low boiling point and additional solvents; extruding said mixture through said die to produce a celluloid article; and removing a second amount of the low boiling point and additional solvents from said celluloid article.