Self-venting vapor-tight microwave oven package
AssigneeMinnesota Mining and Manufacturing Company
InventorsGary A. Isakson, Curtis L. Larson
Life of this patent
Estimating the term…
Abstract
A vapor-tight package has a deposit comprising nonmetallic, microwave-absorbing particles such as graphite dispersed in nonmetallic binder. When heated in a microwave oven, heat built up in the particles may soften and weaken the underlying packaging material, thus venting the package. When the deposit itself is impervious to vapors, it can be positioned over an opening in the package, and the heat only needs to soften and weaken the deposit to vent the package.
Claims17
A vapor-tight package including means for automatically venting through the package upon heating in a microwave oven, wherein the package comprises a sheet of thermoplastic film and a deposit of less extent than the film adhered to said sheet at the point where venting is desired to occur and comprising nonmetallic, microwave-absorbing particles selected from the group consisting of graphite and carbon black dispersed in a nonmetallic binder, which deposit has a thickness within the range from 10 to 300 micrometers, said particles comprising at least 10% by weight of said deposit, the dimensions of the deposit and the concentration of the particles being sufficient to provide sufficient heating of the thermoplastic film when exposed to microwave energy to cause softening of the film sufficient to cause or allow rupture and venting of the package through the softened ruptured film without arcing.
A vapor-tight package including means for automatically venting through the package upon heating in a microwave oven, wherein the package comprises a sheet having either a weakness or an opening at the point where venting is desired to occur and a deposit of less extent than the sheet adhered by an adhesive to said sheet over said weakness or opening and comprising nonmetallic, microwave-absorbing particles selected from the group consisting of graphite and carbon black dispersed in either said adhesive or a nonmetallic binder, which deposit has a thickness within the range from 10 to 300 micrometers, said particles comprising at least 10% by weight of said deposit, the dimensions ofWI the deposit and the concentration of the particles being sufficient to provide heating of the adhesive or nonmetallic binder when exposed to microwave energy to cause softening of either the adhesive or binder and venting of the package through either the weakness or opening and either the softened adhesive or binder without arcing.
Dependencies are inferred from the claim text.