Title:
Novel Packaging Solution for Highly Filled Phase-Change Thermal Interface Material
Kind Code:
A1


Abstract:
A packaging system, packaging method and method of depositing a thin layer of material at a desired location upon a substrate, and in particular a layer of thermally-conductive phase change material at the interface between a heat-dissipating component and heat sink coupled therewith. The packaging comprises a thin layer of material sandwiched between a first base liner and a second top liner. A segment of tape is adhesively bound to the top liner and preferably includes a graspable portion, such as a tab, to enable the same to pull the top liner away from the material to thus leave the layer of material deposited upon the substrate.



Inventors:
Rauch, Robert A. (Dove Canyon, CA, US)
Application Number:
11/571748
Publication Date:
12/11/2008
Filing Date:
07/08/2005
Primary Class:
Other Classes:
257/E23.088
International Classes:
B65B7/28
View Patent Images:



Primary Examiner:
AZIZ, KEITH T
Attorney, Agent or Firm:
Henkel Corporation (Rocky Hill, CT, US)
Claims:
What is claimed:

1. A packaging system for a layer of material comprising: a) a base liner, said layer of material being formed upon said base liner; b) a top liner disposed substantially over said layer of material deposited upon said base liner; and c) a tape segment adhesively bound to at least a portion of said top liner.

2. The system of claim 1 wherein said layer of material comprises a thermally-conductive composition.

3. The system of claim 2 wherein said thermally-conductive composition possesses phase-change properties.

4. The system of claim 1 wherein said segment of tape has a tab formed thereon.

5. The system of claim 1 wherein said base liner and said top liner comprise paper release liners.

6. The system of claim 1 wherein said layer of material and said top liner define a length and a width and said tape extends across a respective one of said length and width defined by said layer of material and top liner.

7. The system of claim 6 wherein said layer of tape further extends to and is adhesively bound to said base liner.

8. The system of claim 7 wherein said tape is adhesively bound to said base liner at a point beyond the peripheral edge defined by said layer of material and said top liner.

9. The system of claim 1 wherein said layer of material comprises a thermally-conductive composition having a thickness of approximately 8 mil.

10. A method for packaging a layer of material comprising the steps: a) providing a base liner; b) depositing said layer of material upon said base liner provided in step a); c) placing a top liner over said layer of material deposited upon said base liner; and d) rolling said base liner and top liner with layer of material disposed therebetween such that said layer of material assumes a desired thickness; and e) adhesively attaching a segment of tape to said top liner positioned over said layer of material in step c).

11. The method of claim 10 wherein in step b), said layer of material comprises a thermally-conductive composition; and wherein in step d), said layer is formed to have a thickness of approximately 8 mil.

12. The method of claim 11 wherein in step b), said thermally-conductive material is a phase-change material.

13. The method of claim 10 wherein in step d), said tape segment is adhesively attached to both said top liner and said base liner.

14. The method of claim 10 wherein in step d), said layer is formed to have a specific surface area.

15. The method of claim 14 wherein said layer of material is formed to have a generally square shape.

16. The method of claim 15 wherein said generally square shape is approximately one inch by one inch.

17. The method of claim 10 wherein following step e) said method further comprises the step: a) forming a tab upon said segment of tape.

18. The method of claim 17 wherein said tab is formed by folding a portion of said tape segment upon itself.

19. A method of applying a pre-packaged layer of material upon a desired portion of a substrate comprising the steps: a) providing a pre-packaged layer of material, said pre-packaged layer of material comprising: i) a base liner and a top liner, said layer of material being disposed between said base liner and top liner; and ii) a tape segment adhesively bound to at least a portion of said top liner; b) removing said base liner from said packaging such that a portion of said layer of material is exposed; c) placing said exposed layer of material in step b) upon the desired portion of said substrate; and d) pulling said tape with said top liner adhesively bound thereto away from said layer of material positioned upon said substrate in step c).

20. The method of claim 19 wherein in step a), said layer of material comprises a thermally-conductive material and wherein in step c), said substrate comprises a heat sink.

21. The method of claim 20 wherein said thermally-conductive material comprises a phase change material.

22. The method of claim 19 wherein in step a), said base liner and said top liner comprise paper release liners.

23. The method of claim 19 wherein step c) further comprises adhesively attaching a portion of said tape segment to said substrate.

24. The method of claim 10 wherein said method further comprises the step: a) forming said packaged layer of material in step d) as a roll.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

Compositions, systems and methods for facilitating the transfer of heat from a heat dissipating component to a heat sink are well-known in the art. Exemplary of such compositions, methods and systems include those disclosed and claimed in U.S. Pat. No. 5,904,796, issued May 18, 1999, entitled ADHESIVE THERMAL INTERFACE & METHOD OF MAKING THE SAME; U.S. Pat. No. 5,912,805, issued Jun. 15, 1999, entitled THERMAL INTERFACE WITH ADHESIVE; U.S. Pat. No. 6,483,707, issued Nov. 19, 2002, entitled HEAT SINK & THERMAL INTERFACE HAVING SHIELDING TO ATTENUATE ELECTROMAGNETIC INTERFERENCE; U.S. Pat. No. 6,616,999, issued Sep. 9, 2003, entitled PREAPPLIABLE PHASE CHANGE THERMAL INTERFACE PAD; U.S. Pat. No. 6,652,705, issued Nov. 25, 2003, entitled GRAPHITIC ALLOTROPE INTERFACE COMPOSITION AND METHOD OF FABRICATING THE SAME; and U.S. Pat. No. 6,672,378, issued Jan. 6, 2004, entitled THERMAL INTERFACE WAFER & METHOD OF MAKING & USING THE SAME, the teachings of which are expressly incorporated herein by reference.

Among such products and systems that are commercially available include those products sold under the trademarks POWERSTRATE, THERMSTRATE, ISOSTRATE, MCM-STRATE, EMI-STRATE, THERMSTRATE TC and POWERFILM, all of which are produced by Power Devices, Inc. of Laguna Hills, Calif., which is a subsidiary of Henkel, Inc. of Gulph Mills, Pa.

Transferring heat away from a heat-dissipating component, which typically comprises microprocessors and other electronic componentry, is essential for many electronic devices to function properly. To the extent heat is not removed, such electronic componentry will operate sub-optimally and can become damaged, sometimes irreparably. The aforementioned compositions and systems address such issue by facilitating the ability to draw heat away from the heat generating source to a heat dissipating object, which typically comprises a heat sink. With respect to the latter, heat sinks are typically formed from a material having excellent heat conducting properties, such as aluminum, that are provided with an enlarged surface area, typically defined by protuberances, fins, or other like materials that are operative to dissipate the heat transferred thereto into the surrounding air. With respect to the latter, fans are frequently utilized to thus provide adequate air circulation and thus facilitate the dissipation of heat.

The aforementioned compositions, systems and methods for transferring heat are typically deployed at the juncture between the heat dissipating component and the heat sink. In this regard, such heat transfer materials are typically operative to ensure proper mechanical contact between the heat dissipating component and the heat sink coupled therewith insofar as it widely recognized that mechanical contact between such componentry greatly facilitates the ability of heat to be transferred thereacross.

To that end, it is widely recognized that phase change materials, such as those disclosed in U.S. Pat. Nos. 5,904,796; 5,912,805; 6,483,707; 6,616,999; 6,652,705; and 6,672,378 are exceptionally effective to facilitate in the transfer of heat across the thermal interface. Such phase change materials, which are formulated to remain solid at room temperature but liquefy at temperatures at or near the operating temperature of the electronic componentry to which the material is utilized, offer the advantage of ensuring mechanical contact between the heat dissipating component and heat sink during operation of the device, but thereafter solidify so that the same remains within a discreet area at the interface between the electronic component and heat sink. The latter aspect is particularly important insofar as the property of such phase change material to remain solid greatly facilitates the ability of such materials to be applied at the desired juncture between the heat dissipating component and heat sink.

Despite the ideal properties of phase change materials to facilitate the transfer of heat, however, are drawbacks associated with the ability to package, ship and apply such materials at the interface between the electronic component and heat sink to be coupled therewith. Specifically, most phase change materials are formed to have as minimal thickness as possible in order to maximize the transfer of heat and thus are very fragile. Moreover, due to the phase change property of such materials, the same are easily torn or ablated during application, and thus can be easily damaged or improperly applied.

To address such shortcomings, most phase change materials are typically mounted upon a substrate that facilitates the ability of such materials to be manufactured, shipped and ultimately secured at the interface between a heat dissipating component and a heat sink. The use of a substrate, however, is well-known to impede the flow of heat by introducing additional thickness at the interface, as well as by introducing a separate layer of material that extends across the path of heat flow. As a consequence, the advantages of utilizing a substrate can and frequently are outweighed by the impediment to heat flow that such structures cause.

As such, there is a substantial need in the art for a new packaging system and method that is operative to enable thin layer materials, and in particular phase change materials operative to facilitate the transfer of heat from a heat dissipating component to a heat sink, to be packaged, shipped and ultimately applied to the interface between a heat dissipating component and heat sink that preserves the shape and integrity of material, allows for extremely accurate and reproducible application, and, in the context of thermally conductive compositions, eliminates the need for a substrate to be deployed to position such materials at the interface between the heat dissipating component and the heat sink. There is likewise a need for such a system and method that is of extremely simple construction, low cost, simplistic to use, and can be readily implemented utilizing existing technology. There is additionally a need in the art for such a system and method that can be used with virtually any type of phase change material, as well as any other types of films and layers of materials that must be precisely fabricated, shipped and applied.

BRIEF SUMMARY OF THE INVENTION

The present invention specifically addresses and alleviates the above-identified deficiencies in the art. In this regard, the present invention is directed to packaging systems and methods for packaging a thin layer of material, as well as a method for applying such layer of material at a discrete location upon a substrate. The present invention is particularly suited for the packaging and application of phase change materials, and in particular phase change materials for facilitating the transfer of heat from a heat dissipating component to a heat sink.

According to a preferred embodiment, the thin layer of material sought to be packaged is disposed between a first base liner and a second top liner such that the layer of material is confined or sandwiched between the first base liner and second top liner. Preferably, the layer of material is rolled into a film contained between the base liner and top liner. To the extent desired, the layer of material with top layer positioned thereover may be cut to have a desired shape or footprint to thus match the dimensions of a given thermal interface. For example, it is contemplated that the layer of material with top liner formed thereon may be cut to assume one inch by one inch square shapes.

Once so formed, an elongate segment of tape is adhesively attached across all or a portion of the top liner, and preferably is provided with a length sufficient to enable the tape segment to extend over and across the top liner such that at least one or both free ends of the tape can adhesively attach to the base liner. Preferably, the layer of tape will be provided with a tab or some other mechanism. In a preferred embodiment, the base liner and layer of tape will extend beyond the top liner and layer of material sandwiched therebetween such that the layer of tape will come into contact with and adhesively bind to the base liner. In such preferred embodiment, the layer of material disposed between the top and base liners will in essence be encapsulated to thus provide a further degree of protection to the layer of material that will ultimately be deposited at the thermal interface.

In order to apply the layer of material, the user will initially remove the base liner to thus expose the layer of material on one side. To that end, the base liner may simply be peeled away from the layer of material as per conventional practice. In those embodiments deploying packaging whereby the layer of tape and base liner extend over and encapsulate the top liner and layer of material, the tape and base liner will initially be removed from one another.

Once the layer of material is exposed, the same is deposited directly upon the substrate, namely, that portion of the heat sink defining the thermal interface. Such application will typically involve merely placing the exposed layer of material at a target site upon a substrate, namely, the thermal interface, and thereafter rapidly pulling the tape adhesively bound to the top layer away from the substrate. In a more highly preferred method, the system will utilize a piece of tape extending over the top liner and layer of material disposed there underneath with the extended portion of tape being utilized to first tape the exposed layer of material at a target site upon the substrate. By gently pulling the tape upward, the top liner adhesively bound thereto will peal away from the layer of material, with the material staying at rest and remaining adhered to the interface due to its much greater inertia than the tape and top liner. In this regard, pulling on the tape which is adhesively attached to the interface creates a resistive force opposite to the pull. At the point where the adhesive stops, the pull continues and the resistive force stops, resulting in a rate of change of acceleration being imparted to the top liner through the tape. The resulting acceleration of the top liner is not transferred to the material due to incomplete adhesion between the material and the top liner. The material stays at rest and remains on the interface surface while the top liner is removed for final assembly. As a consequence, the layer of material is precisely and uniformly put into position quickly and easily, and further, advantageously dispenses with the need for any type of substrate to properly position such material.

It is therefore an object of the present invention to provide a packaging system, method of packaging, and method of applying a layer of material at a desired location upon a substrate, and in particular a layer of phase change material operative to facilitate the transfer of heat from a heat-dissipating component to a heat sink, that is exceptionally more reliable, of simple construction, and substantially faster and easier to utilize than prior art packaging and application techniques.

Another object of the present invention is to provide packaging system, method of packaging, and method of applying a layer of material at a desired location upon a substrate, and in particular a layer of phase change material operative to facilitate the transfer of heat from a heat-dissipating component to a heat sink, that provides for better product protection and substantially conserves the amount of material utilized to facilitate the transfer of heat than prior art practices.

Still further objects of the present invention are to provide a packaging system, method of packaging, and method of applying a layer of material at a desired location upon a substrate, and in particular a layer of phase change material operative to facilitate the transfer of heat from a heat-dissipating component to a heat sink, that is of simple construction, can be readily implemented utilizing known manufacturing techniques and materials, and substantially minimizes labor associated with the application of heat-transfer compositions to the interface between a heat-dissipating component and heat sink coupled therewith.

BRIEF DESCRIPTION OF THE DRAWINGS

These as well as other features of the present invention will become more apparent upon reference to the drawings.

FIG. 1 is a cross-sectional view of a layer or pad of material for facilitating the transfer of heat as contained within a package constructed in accordance with the preferred embodiment of the present invention.

FIG. 2 is the cross-sectional view of FIG. 1 wherein the lower base liner of the packaging is shown removed.

FIG. 3 is a cross-sectional view of a heat sink depicting a portion of the layer of material and packaging in FIG. 2 applied thereon.

FIG. 4 is the cross-sectional view of FIG. 3 wherein a segment of tape and upper liner of the packaging are shown being removed with the layer of material remaining in place upon the heat sink.

FIG. 5 is a top view of a dispensing system for use in dispensing the packaged materials of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The detailed description set forth below is intended as a description of the presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the functions and sequences of steps for constructing and operating the invention. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments and that they are also intended to be encompassed within the scope of the invention.

Referring now to the figures, and initially to FIG. 1, there is shown a preferred packaging system 10 for a thin layer of material 14, the latter preferably comprising a single layer or film of thermally-conductive material having phase change properties. In this regard, it is expressly contemplated that packaging 10 will be particularly well suited to facilitate the manufacturing, shipping, handling and ultimate application of such thermally-conductive material, such as 14, that has not heretofore been available. Along these lines, it is expressly contemplated that the packaging 10 will be exceptionally well-adapted for use with certain thermally-conductive phase change materials produced by Power Devices, Inc., and in particular its Powerstrate Xtreme phase change materials.

As illustrated, the packaging comprises a layer of material 14 sandwiched between a first base liner 12 and top liner 16. Preferably, such sandwich-type arrangement is formed by depositing the layer of material 14 between liners 12, 16, the latter of which preferably comprising paper release liners, such that the layer is ultimately formed to have a thickness of between approximately 2 to 20 mil. with approximately 8 mil. being preferred. In a highly preferred embodiment, the base liner will comprise 54 lb. zero release paper and the top liner will comprise 42 lb. zero release paper. To facilitate the rolling of such compound, such compound is preferably heated to a temperature of approximately 60° C. In this regard, because it is expressly contemplated that such layer of material 14 will comprise a thermally-conductive phase-change material, it is believed that such manufacturing process is preferred insofar as such material is inherently tacky and it is desired that the same be formed as a free standing film having a uniform thickness. As will be readily appreciated, however, it is contemplated that all other types of manufacturing processes whereby the layer of material 14 can be formed to assume the sandwich-type configuration between liners 12, 16, whether it be by first depositing the layer of material 14 upon base liner 12 and thereafter covering the same with top liner 16, should be deemed to fall within the scope of the present invention.

In the embodiment depicted, top liner 16 will be formed to have the same dimensions as layer 14 such that both items 14, 16, will define a continuous peripheral edge. In this respect, it is contemplated that the layer 14 and top liner 16 may be selectively cut or formed upon base liner 12 according to a particular shape or footprint as may be desired for a given application. For example, layers have been formed to fit heat sink interfaces as big as 5″×6″. Alternatively, it is contemplated that layer 14 and top liner 16 may be cut to assume specific types of geometric shapes, and in particular generally square-type shapes of one inch by one inch, as is typical for the sizes of most thermal interfaces currently in use.

Extending across top layer 16 is a strip or segment of adhesive tape 18, the latter being adhesively bound to top layer 16. In the preferred embodiment shown, the segment of tape 18 will be provided such that the same extends over the width or length of the layer of material 14 and top layer 16, as illustrated by the segments 18a, 18b, respectively. According to such embodiment, the tape 18, via such extended portions 18a, 18b, can adhesively bind to base liner 12. Advantageously, by extending completely about the layer of material 14, the bottom liner 12 and segment of tape 18 cooperate to encapsulate and protect the layer 14 contained therewithin.

In a preferred although optional embodiment, at least one portion of the tape 18 will be provided with a tab or other type of graspable portion that can enable the tape 18 to be pulled away, discussed more fully below. In the embodiment shown, tape segment 18 is provided with first and second tabs 20a, 20b that can be utilized to facilitate both placement of the layer of material 14 and removal of the tape segment 18. In this respect, it is contemplated that such tabs 20a, 20b, may be defined merely by folding the ends of the tape upon itself with the adhesive side of the tape binding with itself and the outer non-adhesive side defining the tab 20a, 20b. With respect to preferred types of tape that may be utilized, it is presently contemplated that conventional shipping tape such as SMI Polyfilm, P/N 1864000685, 1⅝″ wide, 1 mil thick. Other commercial alternatives include Scotch #810 Magic Tape and Intertape 1100, #F4218, 2″ wide, 2 mil thick.

While in its packaged state, as depicted in FIG. 1, the layer of material 14 can be shipped and handled as needed. Advantageously, such packaged condition enables the free standing layer of material 14 to be protected and maintain its shape and thickness without the need of a substrate. Typically, most layers of phase change materials must either be formed upon substrates or otherwise provided in block form for subsequent application via excoriation and the like. In this regard, there has not heretofore been available a method for packaging a single layer of film that further facilitates the ability of the same to be directly applied to a thermal interface.

With respect to this latter aspect of the invention, there is shown in FIGS. 2-4 the sequential steps for applying the layer of material 14 as secured within packaging 10. Referring initially to FIG. 2, the initial step in applying the layer of material 14 begins with the removal of base liner 12, which can be accomplished by simply peeling away base liner 12 from the layer of material 14. In this respect, it is well-known in the art that layers 12, 14 may be formulated such that layer of material 14 adheres more strongly to the top layer 16, as opposed to base layer 12. The ability to fabricate and/or select liners 12, 14 to achieve that end is readily understood within the art.

Once the base liner 12 has been removed, as shown in FIG. 2, the exposed layer of material 14 with upper layer 16 and tape segment 18 coupled therewith are selectively positioned at a desired area upon the substrate, namely, a heat sink 22, as shown in FIG. 3. To that end, the layer of material 14 need only be lightly compressed upon the interface. In this regard, the layer 14 will be caused to stick in place due to the tacky nature of such compositions. Advantageously, and unlike other prior art methods, there is no requirement during application of layer 14 that the heat sink 22 be either preheated or otherwise heated and thereafter cooled during application.

Once positioned upon the substrate, a tab (or a respective one of the tabs, such as 20b as shown), is gently pulled upward to thus cause the layer of material 14 to remain in position at the desired location upon the heat sink 22, as shown in FIG. 4. In this regard, it is presently understood that the pulling of tape segment 18 and top liner 16 adhesively bound thereto causes top liner 16 to readily remove from layer 14 due to the latter's greater inertia and incomplete adhesion to the top liner 16. Such forces, coupled with the sticky nature of the phase change material, causes the layer of material 14 to adhere to the heat sink as opposed to remaining stuck upon top liner 16. Once the layer of material 14 is deposited in the desired position, the thermal pathway can be completed whereby the heat-dissipating componentry is coupled to the heat sink 22 with the layer of material 14 being disposed therebetween.

Referring now to FIG. 5, there is shown another aspect of the present invention, namely, a dispensing system for use in distributing and applying the packaged materials of the present invention. As shown, the packaged product will be formed as a roll 24, as per conventional practice of shipping and storing thermally conductive materials. In this regard, and as is illustrated, such rolled products are typically mounted upon a base 26 having one or more dowels 28 distributed thereabout. The dowels 28 are operative to make a segment of the rolled heat transfer material accessible such that a desired length of material can be cut from the roll of tape. Such an arrangement advantageously allows for rapid access to the thermally conductive material to thus expedite the application process.

Additional modifications and improvements of the present invention may also be apparent to those of ordinary skill in the art. Thus, the particular combination of parts and steps described and illustrated herein is intended to represent only certain embodiments of the present invention, and is not intended to serve as limitations of alternative devices and methods within the spirit and scope of the invention.