PARTICULATE INSULATING LINER FOR AN ARTICLE OF CLOTHING

TECHNICAL FIELD

[0001] This invention relates generally to clothing and garment articles and, more particularly, to insulating garments as well as insulating garment articles such as boot liners or other clothing inserts that are used in conjunction with an article of clothing.

BACKGROUND OF THE INVENTION

[0002] Incorporation of insulating liners with the use of an article of clothing is known. As used herein, "clothing", "garment", or "article of clothing" includes not only under and outer wear (shirts, blouses, jackets, coats, pants, shorts, skirts, underwear, etc.), but also such things as footwear, gloves, blankets, sleeping bags, and other articles used to provide protection or comfort against the elements. Such insulating liners when used in combination with the overlaying article of clothing shields the user against uncomfortably cold or hot temperatures and high levels of moisture. Various insulating materials for insulating liners that have been used in the textile industry include felt, fleece, flannel, wool, various forms of latex foam, or the like. Although flexible and readily adaptable for textile applications, such materials are often provided in relatively thick slabs that can be bulky, thereby requiring the user, for example, to use a larger sized garment in order to fit the insulating insert or liner. Also, such materials often do not exhibit effective insulative properties in extremely high or extremely low temperature-related environments.

[0003] Silica aerogels have been known to exhibit excellent thermal insulation performance and have been readily adapted for use in high temperature thermal insulation and cryogenic thermal insulation applications including, for example, advanced space suit designs by NASA. Aerogels, as that term is used herein, include polymers with pores with less than 50 nanometers in porous diameter. In a process known as sol-gel polymerization, monomers are suspended in solution and react with one another to form a sol, or collection, of colloidal clusters. The larger molecules then become bonded and cross-linked, forming a nearly solid and transparent sol-gel. An aerogel of this type can be produced by carefully drying the sol- gel so that the fragile network does not collapse.

[0004] Thermal insulation blankets using aerogels have been developed, and aerogel materials are now commercially available in which the aerogel is impregnated or otherwise incorporated into a carbon-based media. One difficulty with using silica aerogels is that the aerogel tends to be dusty, even when supported by a carrier material. If the aerogel material is not properly contained and sealed within the liner assembly, the dust particles can escape the liner and into the atmosphere thereby diminishing the effective insulative life of the insulating liner. Also, the dust particles can present problems during manufacturing of clothing articles. Such problems can include contamination of surfaces that should be clean for gluing, welding, sewing, or other like operations.

[0005] Another difficulty is that aerogel blankets are generally provided as slabs of uniform thickness. Such uniformly thick blankets are not conducive for use in articles of clothing requiring insulation of variable thickness or close contour fit. If an article of clothing or an insulating liner has contours defining varying thicknesses of insulation space, then a uniformly thick aerogel blanket will be too thick for some portions and too thin for other portions. In other words, a uniformly thick aerogel blanket can overfill or underfill an insulation space. Insulation underfill can result in insufficient insulating properties. Insulation overfill can result in excessively bulky liners or clothing articles and, thus, can restrict movement of a wearer or otherwise discomfort the wearer. Also, use of aerogel blankets is not conducive to providing custom insulated articles of clothing, because the blankets are installed when the clothing is manufactured. Therefore, an aerogel blanket may not always suitably comfort a wearer for all clothing applications.

SUMMARY OF THE INVENTION

[0006] In accordance with one aspect of the invention, there is provided a particulate insulating liner for an article of clothing, comprising a first layer, a second layer, and a particulate insulating layer sealed between the first and second layers, wherein the particulate insulating layer comprises an aerogel material carried by a particulate substrate. The liner can be used or incorporated into various types of clothing. As an example, it can be incorporated into a boot with the layers comprising inner and outer layers of at least a part of the boot, and the particulate insulating layer being sealed between the inner and outer layers.

[0007] In accordance with one aspect of the invention, there is provided a method of forming particulate insulating liners for articles of clothing. The method includes the steps of:

[0008] providing first and second sheets of an impermeable polymeric material;

[0009] encapsulating at least one particulate insulation layer between said first and second sheets, wherein the particulate insulating layer comprises an aerogel material carried by a particulate substrate; and [0010] cutting said sealed first and second sheets to a desired shape.

[0011] In accordance with yet another aspect of the invention, there is provided a method of producing an article of clothing having a particulate insulating liner. The method includes the steps of:

[0012] providing first and second layers of impermeable polymeric material;

[0013] sealing portions of the first and second layers together to define an insulating space therebetween; and [0014] introducing a particulate insulating layer into the insulating space through at least one valve in at least one of the first and second layers, wherein the particulate insulating layer comprises an aerogel material carried by a particulate substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Preferred exemplary embodiments of the invention will hereinafter be described in conjunction with the appended drawings, wherein like designations denote like elements, and wherein:

[0016] FIG. 1 is a top view of an insulating liner for a shoe;

[0017] FIG. 2 is a cross-sectional view taken along line 2-2 of the insulating liner of FIG. 1 ;

[0018] FIG. 3 is an exploded view of an exemplary process for forming the insulating liner;

[0019] FIG. 4 is a cross-sectional view of a boot including an exemplary insulating liner; and

[0020] FIG. 5 is a cross-sectional view of the boot of FIG. 4 taken through a toe end.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] With reference to the drawings, FIGS. 1 and 2 depict a multiple layer insulating shoe liner 10 comprising an aerogel-containing insulation layer 12 encapsulated within two support layers 14, 16 by a hermetic seal. The insulation layer 12 includes a relatively thin

layer of particulates 12A, 12B that are composed of a dust generating aerogel composite including a nonporous silica matrix supported or carried by a polymeric, fibrous, particulate substrate.

[0022] As shown in FIG. 2, the insulation layer 12 is disposed on an upper surface 13 of the first support layer 14. The liner 10 is completed by disposing the second support layer 16, having a wearing material 18 laminated on an upper surface 22 of a polymeric material layer 20, over the insulation layer 12. The periphery of the first and second support layers 14, 16 are hermetically sealed by a high frequency or ultrasonic welder for encapsulating the insulation layer 12 between the support layers 14, 16.

[0023] As shown in FIG. 1, the insulating liner 10 can include a frontal region 25 which comprises the upper and lower layers 14, 16 bonded together without any insulating material 12 therebetween. This frontal region includes raised contour ridges 27 that comprise cut lines along which the liner 10 can be trimmed to fit various sized shoes.

[0024] The insulation layer 12 is composed of a particulate substrate or carrier material impregnated with an aerogel material. In other words, the particulate substrate carries the aerogel composite. Studies have shown that aerogel composites demonstrate superior insulative properties as opposed to other insulators conventionally used in textile, garment and footwear applications. Based upon their chemical structures, aerogels can have low bulk densities of about 0.15 g/cm ³ or less, and more preferably of about 0.03 to 0.3 g/cm ³ , very high surface areas of generally from about 400 to 1,000 m ² /g and higher, and more preferably of about 700 to 1000 m ² /g, high porosity of about 95% and greater, and more preferably greater than about 97% porosity, and relatively large pore volume with more than about 3.8 mL/g, and more preferably with about 3.9 mL/g and higher. The combination of these properties in an amorphous structure provides low thermal conductivity values of about 9 to 16 mW/m-K at 37°C and 1 atmosphere of pressure for any coherent solid material.

[0025] The particulate carrier used in the insulation layer 12 is a polymeric fibrous material that effectively carries the aerogel composite material with it. The particulate carrier can be a carbon-based material, such as a carbon felt or other fibrous material, or can be formed from polyester or any other material suitable for supporting and retaining the aerogel within the carrier. The fibrous material can include a single type of polymer fiber or can include a combination or matrix of fibers and is somewhat bulky, as compared to the aerogel, and

includes some resilience preferably with some bulk recovery. The use of the particulate carrier minimizes the volume of unsupported aerogel while avoiding degradation of the thermal performance thereof.

[0026] The particulate carrier is chopped, shredded, or otherwise cut from a continuous sheet, strip, blanket, or the like, to any desirable size(s) and/or shape(s) using any suitable tools. For example, relatively small particles 12A and relatively large particles 12B can be cut from a single substrate material or multiple different substrate materials. The larger particles 12B can have a relatively greater resilience for cushioning where it is needed such as in the center of the liner 10 at a heel portion thereof. The smaller particles 12A can establish a relatively greater insulation density for greater insulative performance such as about a perimeter of the liner 10. Suitable aerogel blankets for use in the present invention include Spaceloft ^® AR3101, AR3102 and AR31O3 materials as well as Pyrogel ^® AR5401, all of which are manufactured by Aspen Aerogels, Inc. of Marlborough, MA. The particulate carrier can be produced from an aerogel blanket using conventional textile cutting tools such as scissors, or other tools such as shredders.

[0027] The first support layer 14 is generally composed of an organic polymeric material, such as nylon, polystyrene, polypropylene, polyvinyl chloride (PVC), or the like. Specifically, the PVC material is structurally intact, yet flexible, can be easily cut to a desired size and shape and further provides a somewhat sticky or gripping-like surface that is particularly advantageous for footwear applications. The lower surface 23 of the first support layer 14 readily grips and temporarily adheres to the insole of the shoe. For other textile-like applications, other materials such as nylon, for example, provides a similar structurally integral material suitable for the support layer 14 but does not exhibit such a gripping property, thereby making the liner 10 more adaptable for clothing inner linings and for outer linings where a non-grip surface is desired. In footwear applications, the support layer 14 for the liner 10 is preferably composed of PVC foam having a thickness in the range of about 1.5mm to 2.5mm, and more preferably of about 2.0mm in thickness.

[0028] The second support layer 16 comprises the wearing material 18, about 1.0 mm or less in thickness, secured on the upper surface 22 of the polymeric material layer 20 by lamination, for example. The wearing material 18 is preferably made of a knitted or woven polyester material that can be easily cut to the desired size and/or shape of the liner 10, is

readily adherable to the polymeric material 20, and further provides a comfortable wearing surface for the user. The polymeric material 20 is preferably the same PVC foam material that is used for the first structural layer 14 depending, of course, on the application (e.g., footwear application) in which the liner 10 will be used.

[0029] In the illustrated embodiment, both the first and second support layers 14, 16 are structural layers that not only seal the aerogel material into an enclosed space, but also provide structural features such as cushioning to the shoe insert. Where such structural features are not needed, the layers 14, 16 can instead be implemented in other ways that will be apparent to those skilled in the art.

[0030] The particulate form of the insulation layer 12 can be advantageous for any of the following reasons. A particulate insulating layer provides aerogel insulation in a highly flexible state that is extraordinarily manageable for textile, footwear and other similar applications. Because the particulates can shift, the particulate insulation layer can enable greater freedom of movement of body parts like fingers within a glove, compared to blanket insulation. Also, unlike blanket forms, the particulate form enables the insulation layer 12 to be provided with a variable thickness. Furthermore, the particulate form enables the insulation layer 12 to be provided with variable shapes and sizes of substrate particulates for variable insulation density and cushioning. Moreover, the particulate form enables the insulation layer 12 to be injected into an article of clothing, such as at a point of sale of the clothing, for a custom fit to the purchaser of the clothing. Finally, the particulate form effectively increases the exposed surface area of aerogel particles for increased insulative performance.

[0031] In reference now to FIGS. 1-3, the insulating liner 10 is formed by the following process. First, the insulation layer 12 is provided in suitable size(s) and shape(s) of particulates 12A and laid over an upper surface 24 of a PVC sheet 26. In one exemplary implementation, the insulation layer 12 is first produced in blanket form, such as is available from Aspen Aerogels as discussed above. The blanket form insulation layer 12 is then cut into its constituent particulates 12A. For example, aerogel blanket material can be cut into substantially uniform size and shape particulates. More particularly, a substantially uniformly thick flat aerogel blanket can be shredded lengthwise and then cross-wise into substantially cube shaped particulates such as 1/8" cubes. Any suitable size and/or shape

particulates can be used. In another example, aerogel blanket material can be cut into particulates of varying size and/or shape.

[0032] The PVC sheet 26, after the forming process of the liner 10 provides the first structural layer 14. Since the PVC sheet 26 can be provided in various sizes, more than one insulation layer 12 can be provided on the upper surface 24 to thereby form multiple liner assemblies 10 during a single insulating liner manufacturing process.

[0033] Second, a PVC sheet 28 is pre-preprocessed by laminating a sheet 30 of the knitted or woven polyester material 18 thereon. The combined PVC/polyester panel is then disposed over the insulating layer 12, thereby forming the second structural layer 16 of the insulating liner 10.

[0034] Third, a high frequency (HF) or ultrasonic welder (not shown) is provided including a lower platen 31 and upper die plate 32 having the contours of the shoe liner 10, including the shape, size, and embossments such as dimples 34 (as shown in FIGS. 1 and 3), a logo or the like. The die plate 32 includes one, two, or more outer die-cutting surfaces 36 (only one die cutting surface 36 shown in FIG. 3) for forming one, two or more simultaneous insulating liner assemblies 10. The sheet 26 having the insulating layer 12 thereover as well as the sheet 28 with the laminated material 30 thereon are then positioned on the platen 31 below the die plate 32, and the die-cutting surface 36 is aligned with the insulating layer 12. The die plate 32 then engages the wearing material 30, and presses the two sheets 26, 28 with the insulating layer 12 disposed between them together against the platen 31 while applying a high frequency of about 10-30KHz to weld the sheets 26, 28 together just outside the periphery of insulating layer 12 to thereby encapsulate the insulating layer 12 therebetween. The die plate 32 further die-cuts the sheets 26, 28 with suitable pressure exerted on the layers 14, 16 from the welder and further simultaneously embosses the wearing material 18. A hermetic seal is thus formed between the PVC sheets 26, 28 and the insulting liner 10 is cut and formed having the dimples 34 and contour ridges 27, as well as manufacturers' logos or other embossments formed thereon. PVC foam is just one example of a suitable material that is impermeable to air and capable of being hermetically sealed to another layer of the same material about its periphery. Other suitable materials will be known to those skilled in the art. The welder can be a high frequency plastic welding machine such as is available from Weldech Electric Industry Co., Ltd. of Taichung, Taiwan (www.weldech.com).

[0035] The dimples 34 can comprise areas where the PCV and insulating layers are compressed tightly together such that the dimples comprise indentations in the upper surface. Alternatively, the dimples can be raised areas formed from recesses in the die plate 32. In this latter arrangement, the dimples help provide air flow between the shoe liner and wearer's foot. These dimples can be formed on the first layer 14 as well, thereby allowing airflow between the insert and insole of the shoe. This latter arrangement is also advantageous during manufacturing since the layers 12, 14, 16 can be tightly compressed by the die plate 32 to squeeze out excess air before hermetically sealing the layers 14, 16 during welding. This helps minimize the amount of air trapped in the shoe liner. Furthermore, this manufacturing approach facilitates use of thicker foam layers such as, for example, a 5 mm foam layer. During compression and welding, the foam can be significantly compressed leaving dimples that protrude by several millimeters.

[0036] FIGS 4 and 5 illustrate another presently preferred embodiment of an article of clothing and insulating liner. This embodiment is similar in many respects to the embodiment of FIGS. 1 through 3 and like numerals between the embodiments generally designate like or corresponding elements throughout the several views of the drawing figures. Additionally, the description of the previous embodiment is incorporated by reference and the common subject matter may generally not be repeated here.

[0037] In general, FIG. 4 illustrates an exemplary embodiment of an article of clothing 200 including an insulating liner 210. Any type of article of clothing can be used with the novel aspects discussed herein, but as an example and as shown, the article can include insulating liners integrated into footwear. As used herein, the term footwear includes not only shoes, regular boots, and other protective coverings for the feet, but also more special-purpose footwear such as ski boots, ice skate boots, work boots, and the like. Also, the insulating liner can be integrated into the footwear as a separate, sealed component inserted into the lining of the footwear (e.g., into the sole, upper, etc.) or, as shown in FIGS. 4 and 5, integrated in using structural components of the footwear itself as one or both of the support layers of the liner. Specifically, in FIG. 4 the insulating liner 210 is implemented in a ski boot 200, wherein an aerogel material is contained and sealed within the ski boot 200 between an inner liner and outer molded shell of the boot to prevent aerogel dust particles from escaping the insulating liner 210.

[0038] The ski boot 200 includes an outer molded shell 214 and an inner liner 216 that are separated by an insulation space 21 1. The outer shell provides a foundation and structure for the boot 200, and in this embodiment is used as an outer support layer 214 of the liner 210. The inner lining 216 constitutes an inner support layer 216 of the liner 210. The insulating liner 210 of the boot 200 includes an aerogel-containing insulation layer 212 disposed in the insulation space 211 defined between the first support layer 214 and the second support layer 216. Those skilled in the art will recognize that the first and second layers 214, 216 can also be any other suitable components besides an outer shell of an article or an inner lining of the article. For example, first and second layers can include a single or multi-piece bladder for installation within the boot 200. Those skilled in the art will also recognize that additional layers of other material can also be included in the boot 200. For instance, one or more foam padding layers can also be included in any suitable configuration. As another example, where a porous inner lining is used, a separate impermeable layer can be used to define the insulation space 21 1 between that impermeable layer and the outer shell 214. Other such variations will be apparent to those skilled in the art.

[0039] The first support layer 214 can be a single molded component as shown, but can also include a plurality of components. For example, in a work boot embodiment the first support layer 214 could include a boot-upper molded into a sole (not shown), wherein the upper and sole define a first support layer. In any case, the first support layer 214 can be composed of any suitable material that is preferably impermeable to air and capable of being hermetically sealed to another preferably impermeable layer so as to sealingly contain aerogel material. For instance, the first support layer 214 can be injection molded from any suitable thermoplastic pellet material. In another instance, the first support layer 214 can be formed into shape from any suitable thermoplastic sheet material.

[0040] The second support layer 216 is composed of any suitable material that is preferably impermeable to air and capable of being hermetically sealed to another preferably impermeable layer so as to sealingly contain aerogel material. For example, the second support layer 216 can be composed of an organic polymeric material, such as nylon, polystyrene, polypropylene, polyvinyl chloride (PVC), or the like. The second support layer 216 is sealingly attached to the outer layer 214 in any suitable location, such as at circumferentially continuous top ends 203, 217 thereof, to define a sealed insulating space therebetween for an aerogel containing material. Those skilled in the art will recognize that

other portions of the second support layer 216 can instead or also be sealingly attached to other portions of the outer layer 214.

[0041] The insulating layer 212 occupies at least a portion of the insulating space and is composed of the same particulate carrier material impregnated with an aerogel composite as previously discussed with respect to the insulating layer 12 of FIGS. 1-3. The insulating space is of variable cross-sectional dimension or thickness as depicted in the cross sections of FIGS. 4 and 5. In one example shown in FIG. 4, the insulating space at a front 250 of the boot 200 is greater in dimension or thickness than the insulating space at a rear 252 of the boot 200. Accordingly, a greater volume or thickness of the insulating layer 212 can be disposed between the inner and outer layers at the front of the boot. In another example, shown in FIG. 5, at a top 254 of the boot 200, the insulating space is greater in thickness than the insulating space at a bottom 256 of the boot 200. Thus, the variable thickness insulation space 211 can provide a wearer with more insulation around the tops of a wearer's toes to provide more warmth to the wearer's toes, and/or can provide a wearer with a closer contour fit than can be achieved with blanket insulation.

[0042] As shown in FIG. 5, the insulating liner 210 can include separate insulation chambers defining the insulation space 211. For example, an upper insulation chamber 21 IA is separated from a lower insulation chamber 21 IB by integral projecting walls 258, 260 of the outer shell or first layer 214. The projecting walls 258, 260 include ends 259, 261 that can be fused or otherwise sealingly attached to the second layer 216. Any suitable quantity and configuration of projecting walls can be used to control shifting of particulate insulation material. Those skilled in the art will recognize that the projecting walls 258, 260 can also or instead be provided as integral portions of the second layer 216, or can be provided as pinched or fused portions of both layers 214, 216, or the like. Some shifting of the particulates 212A can be desirable to allow the insulation layer 212 to conform to the particular shape of a wearer. Within each chamber 21 IA, 2 HB, the particulates 212A can be introduced according to a suitable density to allow the insulation layer 212 to generally conform to and hold the shape of the insulation space 211. The particulate insulation layer 212 tends to hold its shape due to the resistance of the individual substrate particles 212A to compression. Moreover, the size and/or shape of the particulates 212A can be varied for different locations within the boot 200. For example, finer shapes and sizes of insulation can be used in more thermally sensitive areas like an upper toe area of the boot 200, whereas

coarser shapes and sizes can be used in other areas like a lower heel area that can require increased cushioning.

[0043] The insulating liner can also generally include valves in communication with the insulation space, wherein each insulation chamber can include one or more valves. In particular, one or more inlet valves 262 are disposed through the outer shell or first layer 214 of the boot 200 to enable insulation to be introduced into the insulation space 21 1. Also, one or more vent valves 264 can be disposed through the outer shell or first layer 214 to enable air to be displaced from within the insulation space 21 1. For example, the vent valves 264 can allow trapped air in the insulation space to escape such as when insulation is being introduced. Those skilled in the art will recognize that the valves 262, 264 could also or instead be provided in the second layer 216 in any suitable combination and configuration.

[0044] The inlet valves 262 can be disposed within respective holes through the shell 214, and can be composed of any suitable material that allows it to be affixed to the shell material. For example, the inlet valves 262 can be composed of a vinyl material so that it can be thermoformed, high frequency welded, or otherwise affixed to the support layer material. In one implementation the inlet valves 262 can include moving parts such as a spring, valve head, and valve seat (not shown). In another implementation the inlet valves 262 can include a static valve element such as a pierceable seal (not shown), which is preferably composed of a resilient material, such as a silicone rubber. Particulates 212A can be injected through such a self sealing valve such as using a relatively large diameter needle (not shown), or can be blown through with a pressurized nozzle (not shown), or the like. As particulates 212A are introduced through the valves 262 into the insulation space 211, air trapped therein is permitted to escape through the vent valves 264.

[0045] The vent valves 264 can also be provided for actively evacuating the insulation space

21 1 to reduce thermal conductivity and thereby yield an increase in the insulative performance of the liner 10. Thermal conductivity of an insulating material is determined by the sum of the following three mechanisms: solid conductivity, radiative or infrared transmission, and gaseous conductivity. Solid conductivity is an intrinsic property of a specific material. For example, solid conductivity is relatively high for dense silica like a single-pane window. In contrast, silica aerogels possess only about a 1 to 10% fraction of solid silica and consist of very small particles linked in a three-dimensional network with

many dead-ends. Therefore, thermal transport through the solid portion of silica aerogel occurs through a very tortuous path and is not particularly significant. Moreover, radiative transmission of silica aerogels is relatively low at low temperatures and is also not particularly significant. However, the space not occupied by solids in an aerogel under atmospheric pressure conditions is normally filled with air or other gases. Such air or gases transport thermal energy through the aerogel.

[0046] Therefore, it is desirable to minimize the gaseous conductivity portion of aerogel thermal conductivity. The mean pore diameter of an aerogel is relatively fine and similar in magnitude to the mean free path of nitrogen and oxygen molecules at standard temperatures and pressures. When the mean free path of a gas, such as nitrogen or oxygen, is greater than the pore diameter of an aerogel, the gas molecules collide more frequently with the pore walls than with each other. Accordingly, the thermal energy of the gas is transferred to the aerogel solid portion, which due to its low intrinsic conductivity effectively slows thermal transfer.

[0047] It is thus desirable to increase the size of the mean free path relative to the aerogel mean pore diameter. The mean pore diameter of the aerogel can be increased in the following ways: filling the aerogel with a gas with a lower molecular mass (and, thus, a longer mean free path) than air; reducing the pore diameter of the aerogel; and lowering the gas pressure within the aerogel. The greatest improvement is found by reducing the gas pressure within the aerogel and, it is only necessary to reduce the gas pressure enough to increase the size of the mean free path of the gas relative to the mean pore diameter of the aerogel. For most aerogels a reduction in gas pressure on the order of 50 Torr is sufficient and desirable. Preferably, the gas pressure is reduced in a range from about 25 to 75 Torr.

[0048] For the reasons discussed above, it is desirable to encapsulate the aerogel insulating layer 212 with an air tight seal and even more desirable to provide the insulating space 21 1 with at least a reduced pressure condition therein and preferably a vacuum or negative pressure condition. Accordingly, the boot 200 can be provided with the vent valve 264 such that air or other gas can be expelled or removed from within the liner 10 to reduce the gas pressure on the aerogel material. The vent valves 264 are preferably sealingly applied to an encapsulating cover such as to one of the support layers 214, 216. In other words, one or both of the support layer 214, 216 includes a sealed valve. The vent valve 264 can be any suitable device for allowing air to be expelled or withdrawn from the liner 210.

[0049] The vent valve 264 can be disposed within a hole through the shell 214, and can be composed of any suitable material that allows it to be affixed to the shell material. For example, the vent valve 264 can be composed of a vinyl material so that it can be thermoformed, high frequency welded, or otherwise affixed to the support layer material. In one implementation the vent valve 264 can further include a static valve element such as a pierceable seal (not shown), which is preferably composed of a resilient material such as a silicone rubber. In another implementation the vent valve 264 can include moving parts such as a spring, valve head, and valve seat (not shown). Those skilled in the art will recognize that any of a number of different types of valves can be used with articles of clothing.

[0050] To evacuate air or other gas from within the liner 210, a needle of a syringe (not shown) can be inserted through the pierceable seal of the vent valve, placed in communication with the insulation space 21 1, whereafter the syringe can be actuated to withdraw air or other gas from within the liner 10. The vent valve pierceable seal tightly surrounds the needle such that no air or other gas passes therebetween. Moreover, the pierceable seal is thus preferably a self-closing element so that when the syringe needle is removed, the pierceable seal elastically recovers to maintain the hermetic seal of the liner 210. Therefore, the vent valve 264 enables air or other gas to be removed from the liner 210 using a syringe or other similar device for withdrawing a fluid. Accordingly, the liner 210 can be provided with a reduced pressure condition therein, and preferably a negative pressure or vacuum condition, to enhance the insulative properties of the liner 210.

[0051] In another example, not shown, the vent valve 264 can instead be a one way valve, or check valve, with a dynamic valve element that is biased to a normally closed position. In this example, a suction device such as syringe, pump, vacuum, or the like can be applied against the one way valve and then activated to pull the dynamic valve element away from its normally closed position and thereby allow air or other gas to be withdrawn from the liner 210. When the suction device is deactivated or removed from the one way valve, the dynamic valve element is biased back to its normally closed position to seal the liner 210. The dynamic valve element can be biased in any suitable manner such as by a separate spring, or by inherent elastic properties of the valve element, or the like. According to another aspect of this example, air or other gas can be expelled, instead of withdrawn, through the one way valve.

[0052] In other words, the liner 210 can be compressed to such an extent that the aerogel- containing insulating layer 212 gets compressed to a fraction of its normal height. The insulating layer 212, however, is preferably resilient such that it tends to recover its normal shape after being compressed. Accordingly, a compression force is applied to the liner 210 to expel air or other gas through the one way valve and thereby reduce the interior volume of the liner 210 to substantially the external size of the compressed insulating layer 212. Thereafter, the compression force is released and the compressed insulating layer 212 at least partially recovers its original size and shape thereby tending to at least slightly increase the interior volume of the liner 210. This process tends to yield a reduced pressure condition, and preferably a negative pressure or vacuum condition, within the liner 210 to enhance the insulative properties of the liner 210.

[0053] It is to be understood that the foregoing description is of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. Also, although the above description refers to both aerogels and aerogel composites, it will be appreciated by those skilled in the art that the aerogel composites comprise aerogels that have been formed with another substance, and that either aerogels per se or aerogel composites can be used without departing from the scope of the invention. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.

[0054] As used in this specification and appended claims, the terms "for example" and "such as," and the verbs "comprising," "having," "including," and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.