Patent ID: 11969928
Assignee: VISKASE COMPANIES, INC.
Field: Surface technology, coating (Chemistry)
Classification: CPC B  A  C  G | IPC A  B  C  G

Claim 19:
20. A method of manufacturing the detectable thermoplastic food packaging film of claim 2,
wherein the method comprises the following steps:
(i) a first step of introducing detectable particles into a molten plastic resin to produce a mixture comprising the molten plastic resin and the detectable particles,
wherein the detectable particles are permanently magnetic and comprise a hydrophobic surface-modification being at least one of protective against oxygen and protective against oxidation,
wherein the surface-modification of the detectable particles is bonded to the surfaces of the detectable particles,
wherein the detectable particles comprise a weight-related specific saturation magnetization of at least 50 Am2/kg iron (Fe),
wherein the surface-modification of the detectable particles comprises inorganic, organic or inorganic-organic polymers selected from the group consisting of polysiloxanes, polyacrylates, polymethacrylates, polyacrylamides, starch-based polymers, cellulose-based polymers, polysaccharides, polyaminosaccharides and biopolymers as well as mixtures and combinations thereof, and
wherein the detectable particles are introduced into the molten plastic resin in the form of a particulate compounded mixture comprising the detectable particles together with and distributed in a carrier plastic resin, wherein the particulate compounded mixture comprises the detectable particles in amounts in the range of from 10 to 80 wt. %, based on the particulate compounded mixture;

(ii) followed by a second step of extruding the mixture comprising the molten plastic resin and the detectable particles, so as to obtain a thermoplastic food packaging film comprising the detectable particles incorporated therein in homogeneous distribution.