LIGHTWEIGHT RF SHIELDING CONDUCTIVE ELASTOMERIC TAPE
20200010739 ยท 2020-01-09
Inventors
- Bryan T. Wyrebek (Bristol, CT, US)
- Alexander T. Smith (Simsbury, CT, US)
- Jared DG Butlin (Longmeadow, MA, US)
Cpc classification
C09J2301/122
CHEMISTRY; METALLURGY
H05K9/0081
ELECTRICITY
C09J2301/41
CHEMISTRY; METALLURGY
C09J2203/326
CHEMISTRY; METALLURGY
International classification
H05K9/00
ELECTRICITY
Abstract
A lightweight electromagnetic wave shielding tape is disclosed. The tape includes a first polymer protective layer, a calendered conductive material layer coupled to a bottom side of the first polymer protective layer, and a second polymer protective layer coupled to a bottom side of the conductive material layer so that the conductive material layer is encapsulated within the protective layers. An adhesive layer can also be applied to one of the protective layers.
Claims
1. A conductive elastomeric tape, comprising: a first polymer protective layer; a conductive material layer coupled to a bottom side of the first polymer protective layer; and a second polymer protective layer coupled to a bottom side of the conductive material layer, wherein the conductive material layer was processed through a calender apparatus.
2. The conductive elastomeric tape of claim 1, wherein the first polymer protective layer is made from a material selected from the group consisting of thermoplastic, thermoset, thermoplastic elastomer, elastomer or ionomer.
3. The conductive elastomeric tape of claim 1, wherein the first polymer protective layer is made from a material selected from the group consisting of epoxies, RTV silicone, peroxide cured silicone, platinum cured silicone, thermoset polyurethane, UV cured polyurethane thermoplastic polyurethane, polypropylene, polyethylene, nylon 6, nylon 66, ethylene (meth)acrylic acid or polyamides.
4. The conductive elastomeric tape of claim 1, wherein the first polymer protective layer includes a filling material.
5. The conductive elastomeric tape of claim 4, wherein the filling material includes material selected from the group consisting of multi wall carbon nanotube, single wall carbon nanotubes, high aspect ratio carbon nanotubes, graphene, reduced graphene oxide, graphite, silver coated graphite, nickel coated graphite, copper coated graphite, gold coated graphite, magnetically permeable materials, ferrites, iron powder, copper powder, nickel powder or silver powder.
6. The conductive elastomeric tape of claim 1, wherein the conductive material layer includes a base material that is selected from the group consisting of elastomers, thermoplastic polymers, cellulose fiber, carbon, fiberglass, composites, thermoset polymers or basalt.
7. The conductive elastomeric tape of claim 6, wherein the conductive material layer includes a conductive material that is selected from the group consisting of intrinsically conductive polymers, metals, carbon or metal oxides.
8. The conductive elastomeric tape of claim 3, wherein the second polymer protective layer has a same composition as the first polymer protective layer.
9. The conductive elastomeric tape of claim 1, wherein the conductive elastomeric tape weighs between 2.5 to 5 ounces per square yard.
10. The conductive elastomeric tape of claim 1, wherein the first polymer protective layer, the conductive material layer, and the second polymer protective layer together form a protective shielding layer that is between 0.004 to 0.008 inches in thickness.
11. The conductive elastomeric tape of claim 1, wherein the conductive elastomeric tape has a thickness of between 0.005 to 0.008 inches.
12. The conductive elastomer tape of claim 1, wherein the conductive layer includes silver and has an electrical resistance of between 0.001 to 0.1 ohms per square.
13. The conductive elastomer tape of claim 1, wherein the conductive layer includes nickel silver and has an electrical resistance of between 0.001 to 0.1 ohms per square.
14. The conductive elastomer tape of claim 1, wherein the conductive layer provides shielding of electromagnetic waves having frequency between 1 KHz to 100 GHz at an attenuation of 0 to 120 dB.
15. The conductive elastomer tape of claim 1, wherein the conductive layer provides shielding of electromagnetic waves having frequency between 1 KHz to 100 GHz at an attenuation of 55 to 90 dB.
16. The conductive elastomer tape of claim 1, wherein the calender apparatus includes at least two calender rollers, an unwind roller, a rewind roller, and a control mechanism that controls the operation of the at least two calender rollers, the unwind roller, and the rewind roller.
17. A conductive elastomeric tape, comprising: a first polymer protective layer; a calendered conductive material layer coupled to a bottom side of the first polymer protective layer; a second polymer protective layer coupled to a bottom side of the conductive material layer; and an adhesive layer coupled to a bottom side of the second polymer protective layer, wherein the conductive elastomeric tape has a thickness of between 0.001 to 0.010 inches.
18. The conductive elastomeric tape of claim 17, wherein the thickness is between 0.005 to 0.009 inches.
19. The conductive elastomeric tape of claim 17, wherein the conductive elastomeric tape weighs between 2 to 8 ounces per square yard.
20. The conductive elastomeric tape of claim 17, wherein the conductive elastomeric tape weighs between 3.5 to 5 ounces per square yard.
21. The conductive elastomeric tape of claim 17, wherein the conductive elastomeric tape provides shielding attenuation of between 0 to 120 dB.
22. The conductive elastomeric tape of claim 17, wherein the conductive elastomeric tape provides shielding attenuation of between 55 to 85 dB.
23. The conductive elastomeric tape of claim 17, wherein the conductive elastomeric tape provides shielding attenuation of between 55 to 85 dB from electromagnetic waves of between 1 KHz to 100 GHz.
24. The conductive elastomeric tape of claim 17, wherein the conductive elastomeric tape has an electrical resistance of between 0.001 to 5 ohms per square.
25. The conductive elastomeric tape of claim 17, wherein the conductive elastomeric tape has an electrical resistance of between 0.01 to 1 ohms per square.
26. The conductive elastomeric tape of claim 17, wherein the first polymer protective layer is made from a material selected from the group consisting of thermoplastic, thermoset, thermoplastic elastomer, elastomer, or ionomer.
27. The conductive elastomeric tape of claim 17, wherein the first polymer protective layer is made from a material selected from the group consisting of epoxies, RTV silicone, peroxide cured silicone, platinum cured silicone, thermoset polyurethane, UV cured polyurethane thermoplastic polyurethane, polypropylene, polyethylene, nylon 6, nylon 66, ethylene (meth)acrylic acid or polyamides.
28. The conductive elastomeric tape of claim 17, wherein the calendered conductive material layer includes a base material that is selected from the group consisting of elastomers, thermoplastic polymers, cellulose fiber, carbon, fiberglass, composites, thermoset polymers or basalt.
29. The conductive elastomeric tape of claim 17, wherein the calendered conductive material layer includes a conductive material that is selected from the group consisting of intrinsically conductive polymers, metals, carbon or metal oxides.
30. A method for manufacturing an elastomeric tape, comprising: calendering a conductive material to produce a conductive material layer by applying pressure and heat to conductive material using at least two calender rollers; coating a top surface of the calendered conductive material layer with a first layer polymer material to form a first protective layer; coating a bottom surface of the calendered conductive material layer with a second layer polymer material to form a second protective layer, and coating a bottom surface of the second layer polymer material with an adhesive material to form an adhesive layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0007]
[0008]
[0009]
[0010]
[0011]
[0012]
[0013]
[0014]
DETAILED DESCRIPTION
[0015] Embodiments of a conductive elastomeric tape and methods for producing a conductive elastomeric tape are described. It is to be understood, however, that the following explanation is merely exemplary in describing the devices and methods of the present disclosure. Accordingly, any number of reasonable and foreseeable modifications, changes, and/or substitutions is contemplated without departing from the spirit and scope of the present disclosure.
[0016]
[0017] The conductive elastomeric tape 10 further includes a conductive material layer 30. This conductive material layer 30 may also be called a shielding layer, and is made up of a base material and a conductive material. Possible materials that may be used as base material include elastomers, thermoplastic polymers, cellulose fiber, carbon, fiberglass, composites, thermoset polymers, and basalt. Specific examples of base material include nylon 6, nylon 66, polyester, polyethylene, polyurethane, viton, and carbon fiber. Possible materials that may be used as conductive material include any of intrinsically conductive polymers, metals, carbon, and metal oxides. Specific examples of conductive materials include polyaniline, graphene, carbon nanotubes, silver, nickel, and copper. Different combinations of base materials and conductive materials can change the product performance to target shielding attenuations for various frequency ranges. Different base materials may also provide different mechanical advantages, such as, higher tensile strength, elongation and temperature degradation resistance, etc. Depending on the material used, the conductive material is capable of shielding to an RF attenuation of 0-120 dB within a frequency range of 1 KHz-100 GHz.
[0018] The conductive elastomeric tape 10 may further include a protective coating 40. The protective coating 40 may include the same or similar composition as protective coating 20, and may be made from a polymer including thermoplastic, thermoset, thermoplastic elastomer, elastomer, or ionomer material. Even more specifically, the protective coating 40 may be epoxies, RTV silicone, peroxide cured silicone, platinum cured silicone, thermoset polyurethane, UV cured polyurethane thermoplastic polyurethane, polypropylene, polyethylene, nylon 6, nylon 66, ethylene (meth)acrylic acid, polyamides, or co-polymers thereof. Protective coating 40 also can include optional filling material, as discussed in relation to protective coating 20 above.
[0019] As shown in
[0020] The conductive elastomeric tape 10 may further include an adhesive layer 50. As shown in
[0021]
[0022] A control mechanism 68 may be used to control the operation parameters of the calendering apparatus 60. For example, the control mechanism 68 may control the operating speeds of each rollers individually so that the rollers 62, 64 and 66 may be operated in different speeds as needed. In addition, the control mechanism may control a nip pressure, which is the pressure exerted by the calendering rollers 66 onto the conductive material 32. The control mechanism 68 may further include a heating control mechanism to control the temperature of the rollers either individually or altogether. The control mechanism 68 may further control other operation parameters of each roller 62, 64 and 66. Exemplary operating parameter range for the calendering apparatus is shown in table 1 below:
TABLE-US-00001 TABLE 1 Controlled nip pressure 0.001 to 1000 tons Line speed control 1 to 1000 linear yards/min Tension control 0.1 to 100 lbs Roll temperature 0 to 600 F.
[0023] To reiterate the disclosure of Table 1, the calendering apparatus 60 may control the calendering rollers 66 to exert a nip pressure between 0.001 to 1000 tons. The rollers 62, 64 and 66 may further be controlled so that the conductive material 32 may travel between 1 to 1000 yards per minute. The rollers 62, 64 and 66 may further be controlled so that the conductive material 32 has a tension between 0.1 to 100 pounds. The rollers 62, 64 and 66 may further be controlled to have a temperature of between 0 to 600 degrees Fahrenheit.
[0024] Since the conductive material 32 can vary in construction and composition, the degree to which calendering is beneficial will be dependent on the material of the conductive base material 32. Just like cold or hot rolling, the conductive material 32 can be passed through the process more than once, if desired. After the material has completed the calendering process, the general benefits that should be observed are as follows: smaller conductive material pore size, smoother surface finish for a better surface conductivity and lower RF surface noise, and increased abrasion resistance. The thinner conductive layer after calendering also allows for less material usage in the protective coating layer, which ultimately drives the overall weight reduction for the product. Roll to roll calendering of the conductive material offers much higher economies of scales versus other similar processes where a substrate is compressed to a smaller thickness. Therefore, roll to roll calendering has a much higher capacity for production volumes and provides the lowest cost of manufacturing.
[0025] To further manufacture the elastomeric tape 10, protective coating must be applied onto the calendered conductive material 30, where a constant thickness of polymer is applied throughout the substrate. For example, a protective polymer coating may be applied to the calendered conductive material 30 by either casting, spraying, dipping, molding, or extruding, so that the protective polymer coating thereafter becomes the protective layer 20 and/or 40 as shown in
[0026] As disclosed above, a reduction of the conductive layer 30 thickness is achieved by the calendering of conductive material 32 to make the conductive material 32 thinner and more conductive with increased RF performance and reduced RF surface noise. The thinner conductive material 32 also reduces the amount of thermosetting protective coating needed because of the reduction in the overall volume the protective coating material needs to fill due to the smaller pore size and thickness in the conductive layer, which ultimately reduces the protective coating and overall thickness and weight of the stack up. Due to the weight reduction in conductive elastomeric tape, all applicable aircraft will see an overall weight reduction and savings on fuel consumption on top of a performance increase. Lastly, the overall thickness reduction in the conductive layer gives the product more flexibility and stretch ability for easier installment onto any surface.
[0027]
[0028]
[0029]
[0030]
[0031]
[0032]
[0033] The conductive elastomeric tape of the present disclosure may be produced with various types of polymers and conductive material, as disclosed above. By varying the composition of the tape and operations of the calendering apparatus, a manufacturer may achieve different product characteristics as needed. Table 2 discloses the type and range of product characteristics that may be achieved for different embodiments of the conductive elastomeric tape of the present disclosure.
TABLE-US-00002 TABLE 2 Lower End of Upper End of Product Characteristic Expected Range Expected Range Shielding Attenuation from 0 decibels 120 decibels 1 KHz to 100 GHz Conductive Layer Surface 0.001 Ohms/square 5 Ohms/square Resistance Elastomeric Tape Thickness 0.001 inches 0.010 inches Elastomeric Tape Weight 2.00 ounces/square yard 8.00 ounces/ square yard
[0034] While the conductive elastomeric tape has been described for use for aircraft for application, it will be appreciated that the application of the disclosed elastomeric tape is not so limited. For example, the products disclosed in
[0035] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. Moreover, the above advantages and features are provided in described embodiments, but shall not limit the application of the claims to processes and structures accomplishing any or all of the above advantages.
[0036] Additionally, the section headings herein are provided for consistency with the suggestions under 37 CFR 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Further, a description of a technology in the Background is not to be construed as an admission that technology is prior art to any invention(s) in this disclosure. Neither is the Brief Summary to be considered as a characterization of the invention(s) set forth in the claims found herein. Furthermore, any reference in this disclosure to invention in the singular should not be used to argue that there is only a single point of novelty claimed in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims associated with this disclosure, and the claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of the claims shall be considered on their own merits in light of the specification, but should not be constrained by the headings set forth herein.