INFUSED LAYER

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] This application claims priority under 35 U.S.C. § 119 from U.S. Provisional Application No. 63/263,453, filed November 3, 2021, the entire disclosure of which are herein expressly incorporated by reference.

[0002] Thermal and acoustical insulating shields have long been known in the art. Such shields may be used in a wide variety of applications, among which are shielding in spacecrafts, automobiles, home appliances, electronic components, industrial engines, boiler plants and the like. Some of such shields have proportionally smaller thermal insulating value and proportionally higher acoustical insulating value, and vice versa.

[0003] In connection with the thermal insulating value, some shields may provide thermal insulation primarily by being a radiation thermal shield. Other shields may provide thermal insulation by being a conduction thermal shield. Other shields may incorporate characteristics of both. For example, pressed and formed sheet metal may be mounted by bolts, nuts, screws, welding, and the like, between an object to be protected, i.e., shielded, for example, the floorpan of an automobile, and a heat source, such as parts of an exhaust system. Such a formed sheet metal shield may provide thermal insulation by re-radiation of heat from the portion of the exhaust system back into the ambient air and/or to other cooler parts of the undercarriage of an automobile. This structure may thermally insulate the floorpan from a portion of the exhaust. Such sheet metal shields, however, may have low acoustical insulating value, and a large portion of noise produced in an adjacent portion of an exhaust system can be transmitted through the floorpan of the automobile and into the passenger compartment. Additional noise can be produced by loose sheet metal shields, which vibrate and/or rattle. Such sheet metal shields may also provide thermal insulation value in connection with conductive heat, since such sheet metal shields may be spaced between the floorpan and the portion of the exhaust. The spacing may provide an air gap between the shield and the floorpan which reduces conductive heat transfer, and to some extent, convective heat transfer as well.

[0004] Where substantial acoustical shielding is also required, sheet metal shields, as described above, may be unsatisfactory. In such requirements, the shields generally may be composed of fibrous materials, such as fiberglass batts, which may provide increased acoustical insulation as well as conduction thermal insulation. However, such insulation can only be used where there are insignificant static and dynamic forces on the fibrous insulation. Fiberglass batts, for example, have very little strength in any direction, i.e., in any of the X, Y or Z directions. Such shields are, however, very useful in certain applications, such as thermal insulation in domestic dishwashers.

[0005] A problem regarding such shields has been encountered by the automobile industry and like industries. As the overall size of automobiles continues to shrink, space within any portion of the assembled automobile is now at a premium. For example, in past designs of automobiles, sufficient proximity existed between the exhaust system of the automobile and the floor tunnel of the automobile such that the usual sheet metal shield could be suspended in the tunnel with specially-provided ears, dogs, or connectors, so as to space that sheet metal shield from the tunnel and from the exhaust system. This provided a radiation barrier to heat transfer from the exhaust system to the tunnel, as well as a conductive and convective heat transfer barrier in view of the spacing between the shield and the tunnel. This design also provided some acoustical insulation. However, with modem designs, the spacing between the exhaust system and the tunnel is now reduced. In many situations, it is now no longer practical to suspend shields between the exhaust system and floor tunnel. Moreover, the reduced spacing correspondingly reduces any air gap remaining between the shield and the tunnel, such that very little conductive and convective heat insulation or acoustical insulation results.

[0006] Because of the foregoing difficulty in modem designs, automobile manufacturers have increased the thickness of the material making up the floor covering inside the passenger compartment, i.e., the insulation between the carpet and the floorpan to decrease the heat transfer from the exhaust system into the passenger compartment. This approach, however, may be expensive, labor intensive, and still unsatisfactory in that a passenger may experience the increased temperature and increased noise. Further, this approach may not shield the exterior of the floorpan, and at higher temperatures, the exterior coating may blister and corrode.

[0007] Fibrous batts may provide very good thermal and acoustical insulation and could potentially be a replacement for the suspended sheet metal shields. The problem with such insulation is that the batts, especially of such inorganic fibers, are usually made by air laying fibers onto a moving belt, and, hence, the fibers tend to stratify in non-discrete layers throughout the thickness (Z direction) of the batts. Since these fibers are not substantially interlocked in the Z-direction, the batt may have a very low Z-directional tensile strength. Even under static loading of its own weight, for example, a batt of fiberglass may simply sag out of its original configuration when suspended from an upper surface thereof. Industry players have expended substantial effort in attempting to provide greater tensile strength to such fibrous batts in the X, Y, and Z directions.

[0008] This present subject matter discloses a thermal and acoustical insulating shield that may be constructed from a nonwoven blend of fibers, and which may provide improved insulation properties with reduced weight and overall size when compared with insulating materials of the prior art. [0009] Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagrammatic illustration showing the layers forming the thermal and acoustical insulating shield according to an embodiment of the present subject matter.

DETAILED DESCRIPTION OF THE DRAWINGS

[0011] The following description is merely exemplary in nature and is in no way intended to limit the present disclosure or the application or use thereof.

[0012] Figure 1 shows a plurality of layers forming the thermal and acoustical insulating shield 100 in accordance with an embodiment of the present subject matter. Each of the layers depicted in Figure 1 may be multiplied, removed, rearranged, repositioned, and/or substituted based on the design requirements and constraints of the application. The thermal and acoustical insulating shield 100 may include organic fiber layers that function as binding layers 115 and 125. An insulating layer 120 of insulating fibers may be disposed between opposite binding layers 115/125 of binding fibers 140. Binding fibers 140 of each binding layer 115/125 may be needledly disposed (via needle punching) through the insulating layer 120 and an opposite binding layer 115/125 to provide tufts 145 of binding fibers 140 protruding through each of the opposite binding layers 115/125 to form a tufted upper surface and a tufted lower surface of the thermal and acoustical insulating shield 100.

[0013] For the purpose of this disclosure the terms “about” and “substantially” are used herein with respect to measurable values and ranges due to expected variations known to those skilled in the art (e.g., limitations and variability in measurements). [0014] For the purpose of this disclosure, the terms “at least one” and “one or more of’ an element are used interchangeably and may have the same meaning. These terms, which refer to the inclusion of a single element or a plurality of the elements, may also be represented by the suffix “(s)” at the end of the element. For example, “at least one source”, “one or more sources”, and “source(s)” may be used interchangeably and are intended to have the same meaning.

[0015] The recitations of numerical ranges by endpoints include the endpoints and all numbers within that numerical range. For example, a concentration ranging from 40% by volume to 60% by volume includes concentrations of 40% by volume, 60% by volume, and all concentrations there between (e.g., 40.1%, 41%, 45%, 50%, 52.5%, 55%, 59%, etc.).

[0016] For purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. Throughout the description, corresponding reference numerals indicate like or corresponding parts and features. One skilled in the art will further understand that any properties reported herein represent properties that are routinely measured and may be obtained by multiple different methods. The methods described herein represent one such method and other methods may be utilized without exceeding the scope of the present disclosure.

[0017] No limitation of the scope of the present disclosure is intended by the illustration and description of certain embodiments herein. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present disclosure. Further, any other applications of the principles of the present disclosure, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the disclosure pertains, are contemplated as being within the scope thereof. [0018] As used herein, the terms “upper” and “lower” are intended only as identifier designations and are not intended to expressly indicate direction. Using the needle punching technique, a high Z-directional (thickness direction) strength between layers may be achieved. This strength may be advantageous in automotive applications where long-term repetitive high static or dynamic loading may occur.

[0019] The tufts 145 on opposite surfaces, such as an upper surface and lower surface of binding layers 115/125, may lock the binding fibers 140 in the form of stitches such that the stitches cannot pull through upon high static or dynamic loading in the Z direction (thickness direction) of the shield 100. The presence of these tufts 145 may greatly increase the Z- directional strength of the shield 100, but the needling may still leave the shield 100 very flexible so that it may be easily bent and shaped to desired configurations.

[0020] While the tufts 145 may provide very high Z-directional strength, the Z- directional strength may be further increased by applying a flexible pressure sensitive adhesive 130 disposed and adhered substantially over the lower surface of binding layer 125. The application of the adhesive 130 may cause the tufts 145 to be somewhat deformed or bent from the plane of the lower surface of binding layer 125 such that the tufts 145 on the lower surface are secured by the adhesive 130. That distortion of tufts 145 may greatly increase the resistance of the binding fibers 140 from pulling from the opposite surface and therefore causing a failure (separation) of the shield 100 in the Z direction. In addition, once the adhesive 130 is set, that adhesive may adhere the tufts 145 to the respective lower surface of binding layer 125, which may further increase the Z-directional strength of the shield 100.

[0021] However, in the present subject matter, that Z-directional strength may be further increased. A protective metallic layer 105 may be permanently adhered by an adhesive 110 to the upper surface of binding layer 115. In an embodiment, the adhesive 110 is a thermoset powdered adhesive. During the application of that adhesive 110 and metallic layer 105, the tufts 145 may be further distorted; e.g., flattened, bent, splayed, bradded, and the like, to further increase the resistance of the needle punched binding fibers 140 from pulling through upon high static or dynamic loading.

[0022] Preferably, a flexible, strippable release liner 135 may be releasably adhered to the lower surface of adhesive layer 130. The application of the release liner 135 and adhesive layer 130 may further distort tufts 145, which may further lock and secure those tufts 145 to the lower surface of binding layer 125.

[0023] The release liner 135 may not be required. When a pressure sensitive adhesive is used in adhesive layer 130, however, it may be necessary to protect the pressure-sensitive adhesive from inadvertently sticking to unwanted objects during shipping and handling of the shield(s) 100. This may also be avoided by inserting a release liner between stacked shields. Upon receipt of a stack of shields 100, individual shields 100 may be removed for application to a series of objects to be protected; e.g., a series of automobiles in a production line.

[0024] When a shield 100 is removed from the stack, the lower surface of the binding layer 125 may have the pressure-sensitive adhesive 130 exposed. When that lower surface is pressed onto an object to be protected, as will be subsequently explained, the tufts 145 may be further distorted as previously described in connection with the application of the metallic layer 105 to the adhesive 110. Accordingly, similar results of the in-place shield 100 may follow when a release liner 135 is used between shields 100 in a stack of shields 100 as occurs when a metallic layer 105 is used. However, care should be taken to ensure that the stack remains in place to protect the pressure-sensitive adhesive 130 on the lower surface. In additional, a preforming operation, as subsequently described, may be difficult to perform with only a release liner 135.

[0025] The shield 100 may be of various thicknesses, depending upon the degree of thermal and acoustical insulation required, the binding fibers of binding layers 115, 125, and the insulating fibers of insulating layer 120. In an embodiment, the shield 100 may have a thickness of between about 0.1 to 2.0 inches. Similarly, depending upon the fibers and application, the weight ratio of the insulating layer 120 to each of the binding layers 115, 125 can vary considerably, but generally, that ratio may be between about 0.5 and 12.0: 1. The weight of each of the binding layers 115, 125 may be different, depending upon the application, but for most applications, the weight of each binding layer 115, 125 may be substantially the same.

[0026] The insulating fibers 120 preferably may be any of the usual inorganic fibers, such as glass fibers, mineral fibers, alumina fibers and the like, but more usually, the insulating fibers are glass fibers (e.g., fiberglass). Where the requirement for thermal insulation is lower and the requirement for acoustical insulation is higher, the insulating fibers need not be inorganic fibers and may be, at least in part, organic fibers, such as polyester fibers, nylon fibers and the like. Those fibers may be solid or hollow, the latter of which provides a greater thermal insulation. The insulating fibers 120, as well as the fibers of binding layers 115, 125 may be infused with aerogel particles, also known as amorphous silica particles. The particles may be disposed substantially uniformly throughout the fibers at the time of manufacture to increase the insulating properties of the shield 100. Preferably, the particles improve the k-value to be 0.015 to 0.030W/m-K at 25°C. The particles may be dispersed throughout the fibers with adhesive or loose. One or more of the insulating fibers 120, and the fibers of binding layers 115, 125 may be substituted with foam or another nonwoven solid, yet flexible material.

[0027] The binding fibers 140 may be normally organic fibers, such as polyester fibers, nylon fibers, olefin fibers, and cellulose acetate fibers.

[0028] The denier of the insulating fibers 120 may vary considerably, but generally, deniers from about 0.1 to 25 may be acceptable in most applications. Likewise, the denier of the binding fibers, e.g. organic fibers, can vary widely, but usually the denier will be between about 2 and 7.

[0029] The fiber length of the insulating fibers may vary from short lengths, e.g., 50 microns, up to long lengths, e.g., 5 inches. Fiber lengths of the binding fibers may normally be between about 0.2 inches and 8.0 inches.

[0030] The needle density in preparing the present batts may vary widely, depending upon the Z-directional tensile strength required for the anticipated static or dynamic loading on the shield 100. However, the needledly disposed binding fibers 140, as shown in FIG. 1, generally may have a needling density of between about 500 and 10,000 needle punches per square inch of the shield 100. Thus, there may be between about 500 and 10,000 tufts 145 per square inch on the upper surface and the lower surface. However, more usually, there may be between about 700 and 5,000 tufts 145 per square inch on the upper surface and the lower surface.

[0031] The increased strength of the needled thermal and acoustical insulation shield 100, especially in the Z-direction, may be generally proportional to the number and size of the tufts 145. Aside from the number of tufts 145, as described above, the tufts 145 should have a size such that the increase in strength of the batt in the Z-direction is at least 50% per 1,000 tufts per square inch, and more preferably about at least 100% per 1,000 tufts per square inch, as opposed to the same batt material but untufted. The increase can, however, be much higher. [0032] The adhesive 110/130 can be any desired known adhesive, but preferably the adhesive is an activatable adhesive, such as an adhesive activated by heat (thermoset), a solvent or pressure; e.g., a conventional polyester adhesive. Thus, the adhesive 110/130 may be activated by heating with a hot air gun or an infrared heater or hot roll or activated by spraying or brushing a solvent thereon or activated by pressure (pressure-sensitive adhesive). The preferred adhesive 110/130, however, may be a pressure-sensitive adhesive. The adhesive 110/130 may be applied to the shield 100 by spraying, coating or a “transfer tape' (a film of adhesive on a release foil or paper).

[0033] The pressure-sensitive adhesive of the preferred embodiment may be chosen from a wide variety of known pressure sensitive adhesives, but a preferred pressure-sensitive adhesive is the commercial acrylate adhesive, and particularly, methacrylate adhesive and ethyacrylate adhesive.

[0034] The metallic layer 105 may be composed of a variety of materials; e.g., plastics, metals, fabrics (woven and nonwoven) and the like, but it may be preferable that the metallic layer 105 be either a metal foil, especially aluminum foil, gold foil, or a plastic foil, especially a polyester plastic foil. More preferably, the foil may have a heat-reflecting color, either naturally or as a pigment in the foil or as a coating on the foil. For example, where the foil is made of aluminum, the aluminum, per se, has a heat reflective color. On the other hand, where the foil is a plastic foil, such as polyester foil, that polyester foil can be coated with aluminum to provide a heat-reflective color. The thickness of the protective foil may vary considerably, but generally the thickness of the foil will be between about 2 mils and 100 mils, although thicknesses will more generally be between about 10 mils and 50 mils. The metallic layer 105 may face the hot surface of the object (e.g., exhaust system) to be shielded from, while the adhesive 130 may be attached to the object to be shielded.

[0035] Similarly, the release liner 135 may be a metal or a plastic or a textile or a paper, but it is preferred that the release liner is a conventional paper foil. The release liner should have a conventional release coating, e.g., a polyolefin coating, on a side thereof which contacts the adhesive, e.g. pressure-sensitive adhesive, so that the release liner may be easily removed from the shield 100 to expose the adhesive 130 for adhering the shield to a surface to be protected. The release liner may be of any desired thickness, but generally that thickness may be between about 1 mil and 50 mils. [0036] The present shield 100 may also be in the forms of layers of shields, where the shield 100 has two layers of shields 100 adhered together by adhesive and having the metallic layer 105 and the release liner 135. Of course, more than two layers could be used.

[0037] The shield 100 may be closed at its peripheries, where the shield 100 is enclosed within a metallic layer 105 by sealing the periphery of the metallic layer 105 and then placing the pressure-sensitive adhesive 130 and release liner 135 on top thereof.

[0038] The shield 100, as described above, may be applied to an object for thermally and acoustically protecting that object. By removing the release liner 135 from the lower surface of the shield 100 (or removing a shield from stack, the pressure sensitive adhesive 130 thereon is exposed. By pressing the shield 100 at the metallic layer 105 sufficiently to configure the shield to contours of the object to be protected, this causes the pressure sensitive adhesive 130 to permanently adhere to the contours. Preferably, the pressing at the metallic layer 105 is a manual pressing. However, if preferred, prior to removing the release liner 135, the shield 100 may be subjected to a preforming step to conform the shield 100 to the general contours of the object to be protected. This may allow less manual forming of the shield 100 to the contours of object to be protected where the contours are quite complex in configuration. The shield 100 may be flexed and pressed to configure and permanently attach the lower surface to the object to be shielded.

[0039] To achieve the tufted surfaces, at least the lowermost barb of any needle should pass through lower surface or upper surface, depending upon the needle direction, sufficiently such that the tufted fibers remain on the respective surface when the needle is withdrawn from the shield 100. Generally, the lowermost barb should penetrate beyond the surface by at least about 1/16 inch, more preferably at least about 1/8 inch, e.g. about 1/3 inch, and even up to as much as i or 3/4 inch. This will ensure that a substantial tuft is placed on the surface with each needle punch. [0040] The present subject matter of the disclosure may also relate, among others, to the following aspects:

[0041] A first aspect relates to a thermal and acoustical insulating shield comprising a first binding layer comprising organic first binding fibers; a second binding layer comprises organic second binding fibers; and an insulating layer disposed between the first binding layer and the second binding layer, wherein the insulating layer comprises a plurality of insulating fibers.

[0042] A second aspect relates to the thermal and acoustical insulating shield of aspect 1, wherein the first and/or the second binding fibers of the first and/or the second binding layers are needledly disposed through the insulating layer to provide tufts of binding fibers protruding through the first and/or the second binding layer.

[0043] A third aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the tufts of binding fibers form a tufted upper surface and/or a tufted lower surface of the first and/or the second binding layers.

[0044] A fourth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the tufts of binding fibers further comprise stitches disposed in a through-layer or thickness direction of the first and/or second binding layers.

[0045] A fifth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, further comprising a flexible pressure sensitive adhesive layer disposed and adhered over a lower surface of the second binding layer.

[0046] A sixth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the lower surface of the second binding layer is distorted by the flexible pressure sensitive adhesive layer to increase pull-through resistance of the first and/or the second binding fibers. [0047] A seventh aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the flexible pressure sensitive adhesive layer adheres tufts of binding fibers protruding through the second binding layer to a tufted lower surface of the second binding layer.

[0048] An eighth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, further comprising a metallic layer adhered to an upper surface of the first binding layer by an adhesive.

[0049] A ninth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the tufts of the binding fibers are distorted by the metallic layer and the adhesive to increase pull-through resistance of the tufts of binding fibers.

[0050] A tenth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, further comprising a flexible, strippable release liner releasably adhered to the flexible pressure sensitive adhesive layer.

[0051] An eleventh aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the shield has a thickness ranges from 0.1 and 2.0 inches.

[0052] A twelfth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the weight ratio of the insulating layer to each of the first and second binding layers ranges from 0.5: 1 and 12.0: 1.

[0053] A thirteenth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the weight of the first and the second binding layers is the same.

[0054] A fourteenth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the insulating fibers of the insulating layer are infused with amorphous silica particles such that the k-value of the insulating layer ranges from 0.015 to

0.030W/m-K at 25°C. [0055] A fifteenth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the denier of the insulating fibers ranges from 0.1 to 25.

[0056] A sixteenth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the denier of the binding fibers ranges from 2 to 7.

[0057] A seventeenth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein a needling density of the needledly disposed first and/or second binding fibers ranges from 500 to 10,000 needle punches per square inch.

[0058] An eighteenth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the metallic layer is a foil having a thickness ranging from 10 mils to 50 mils.

[0059] A nineteenth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the release liner has a thickness ranging from 1 mil to 50 mils.

[0060] A twentieth aspect relates to the thermal and acoustical insulating shield of any preceding aspect, wherein the metallic layer encloses the shield, and a flexible pressure sensitive adhesive layer is disposed and adhered on top of the metallic layer.

[0061] A twenty-first aspect relates to a method of applying a thermal and acoustical insulating shield to an object to be protected, wherein the shield comprises a first binding layer comprising organic first binding fibers, a second binding layer comprises organic second binding fibers, an insulating layer disposed between the first binding layer and the second binding layer, wherein the first and/or the second binding fibers of the first and/or the second binding layers are needledly disposed through the insulating layer to provide tufts of binding fibers protruding through the first and/or the second binding layer, the method comprising applying the shield to contours of the object such that the tufts of binding fibers protruding through the first and/or the second binding layers are distorted. [0062] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Examples have been selected merely to further illustrate features, advantages, and other details of the present subject matter. While examples may serve this purpose, the particular material compositions, amounts, proportions, and other conditions should not be construed in a limiting manner. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.