Apparatus for RF active compositions used in adhesion, bonding, and coating

Abstract

A susceptor composition that can bond two or more layers or substrates to one another and that can be used to coat or cut a substrate. The susceptor composition is activated in the presence of radio frequency (RF) energy. In one embodiment, the susceptor composition of the present invention comprises a susceptor and a carrier. The carrier and susceptor are blended with one another and form a mixture, preferably a uniform mixture. The susceptor is present in an amount effective to allow the susceptor composition to be heated by RF energy. In a preferred embodiment, the susceptor also functions as an adhesive. The susceptor is an ionic or polar compound and acts as either a charge-carrying or an oscillating / vibrating component of the susceptor composition. The susceptor generates thermal energy in the presence of an RF electromagnetic or electrical field (hereafter RF field).

Description

[0001] The present application is a continuation-in-part of application Ser. No. 09 / 404,200, filed Sep. 23, 1999, which is a continuation-in-part of application Ser. No. 09 / 270,505, filed Mar. 17, 1999, which claims the benefit of U.S. provisional application No. 60 / 078,282, the contents of each of which are fully incorporated by reference herein.[0002] This patent application is related to the following co-pending U.S. utility patent application: "Radio Frequency Heating System," -application Ser. No. 09 / 270,507, filed Mar. 17, 1999, the contents of which are incorporated by reference herein.[0003] 1. Field of the Invention[0004] This invention relates generally to the use of media containing ionic compounds and / or nonionic compounds with high dipole moments as a radio frequency (RF) susceptors in RF activated systems.[0005] 2. Related Art[0006] Radio frequency (RF) heating is a well established non-contact precision heating method that is used to generate heat directly within RF s...

AI Technical Summary

Benefits of technology

[0323] An advantage of the present invention is that non-electrically conductive materials can be stacked on top of an adherand without affecting the bonding process. Only composition 2091 is directly heated when the layers are exposed to RF energy having the preferred frequency range of 10 to 15 MHz. Thus, by selectively heating only the composition 2091, multiple layers may be assembled prior to forming the bond between adherands 2090 and 2092. This allows the assembly of complex laminates prior to bonding.

Problems solved by technology

Conventional adhesives are not suitable RF susceptors that can be directly heated and activated by RF heating.

However, these flakes are not well suited for use as susceptors in thin film bonding applications in which physical distortions, discolorations in the surface, or opacity of the bonded films would result from the flakes.

A disadvantage of this type of method is that a tradeoff must be made between the size of the particle employed versus the power level and duration of the inductive heating process.

Another disadvantage of this type of method is the high levels of loading of the medium with RF susceptor particles that is required for efficient activation.

Such high loading levels detract from the physical properties and rheology of the adhesive composition.

Still another disadvantage is the dark color and opacity of the composition, which renders the composition undesirable for many applications.

A disadvantage of this type of film and sealing process is the inherent tendency to also heat the adherand.

When a divalent or a trivalent metal ion is used, the resulting sulfonated polyesters are not ordinarily easily dissipated by cold water, but are more readily dissipated in hot water.

Compositions comprising branched sulfonated polyesters tend to give clear, tacky and flexible films.

For example, under-heating can result in a weak bond due to insufficient wet-out of the adhesive onto the adherands.

Also, over-heating can result in undesirable bond, with thermal distortion or destruction of the adherands, as well as thermal degradation of the thermoplastic composition.

For example, under-heating can result in a weak bond due to insufficient cross-linking.

Over-heating can cause effects such as thermal distortion or destruction of the adherands, as well as thermal degradation and excessive shrinkage of the thermosetting composition.

While the conventional systems are effective in sealing the packages, the use of metallic foils eliminates the manufacturer's ability to perform post sealing inspection, such as metal detection, x-ray, and the like.

Current ink formulations are too "slow in drying" or need excessive heat energy.

The manufacturers of such disposable cameras often do not want to have the shells reloaded and reused by the consumer or a competitor company.

If someone attempts to disassemble device 4900 without application of a suitable electromagnetic field, narrowed section 4916 of male portion 4912 will break or otherwise catastrophically fail resulting in device 4900 being unusable.

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