The present disclosure relates to cushioning materials, methods of making, and articles formed thereby, and in particular, to thermoformed cushioning materials, methods of making, and articles formed thereby
Many different types of products benefit from the inclusion of a material that provides cushioning for, among other things, impact and vibration dampening, resistance to compression, deflection, and the like. One common type of cushioning material that is presently used in a wide variety of applications is open cell foam. The open cells of such foams can trap debris and moisture, thereby supporting the growth of microorganisms such as bacteria and fungi. Therefore, although open cell foams are capable of providing sufficient cushioning for many applications, the tendency to support the growth of bacteria and fungi make it less desirable for body-contacting applications such as sports protective padding, helmet linings, medical pads and braces, seating, and the like. In addition, depending upon the application, it may be necessary to use relatively thick and/or dense open cell foams in order to achieve the desired level of cushioning. As the thickness and/or density of the foam increases, so does the weight, thereby further limiting the applications for open cell foam as a cushioning material.
A relatively lightweight, non-cellular cushioning material is needed in the art.
The present disclosure is directed to, in one embodiment, a sheet of cushioning material. The sheet of cushioning material comprises a first layer comprising a polymeric material. The first layer comprises an upper surface and a lower surface. A plurality of resiliently deformable spaced apart cushioning elements are disposed in the polymeric layer. The cushioning elements comprise a sidewall extending upwardly from the polymeric layer to an upper surface, and an interior chamber defined by the sidewall and the upper surface.
In another embodiment, the cushioning material can comprise a second sheet of cushioning material disposed adjacent to the first sheet of cushioning material, wherein the first and second sheets are disposed such that the upper surface of the cushioning elements of the first sheet are substantially aligned with the spaced regions of the second sheet.
In another embodiment, the cushioning material can comprise a second sheet of cushioning material disposed adjacent to the first sheet of cushioning material, wherein the first and second sheets are disposed such that the upper surface of the cushioning elements of the first sheet are substantially aligned with the upper surface of the second sheet.
In any of the foregoing embodiments, one or more of the sheets of cushioning material can comprise at least one active agent.
In any of the foregoing embodiments, upon application of a force to the cushioning material, the cushioning elements deform from an initial shape in a direction substantially perpendicular to the first layer, and upon release of the force, the cushioning elements return to the initial shape.
Another embodiment is directed to a continuous method of thermoforming a cushioning material. The method comprises introducing a first continuous source of polymeric material into a thermoformer, heating the polymeric material, and molding a plurality of resiliently deformable cushioning elements disposed in the polymeric material. The cushioning elements define an interior chamber comprising an upper region spaced apart from the polymeric layer and a sidewall extending upwardly from the polymeric layer to the upper region.
The above described and other features are exemplified by the following figures and detailed description.
Referring now to the figures, which are exemplary embodiments, and wherein like elements are numbered alike:
At the outset of the detailed description, it should be noted that the terms “first,” “second,” and the like herein do not denote any order or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. Similarly, the terms “bottom” and “top” are used herein, unless otherwise noted, merely for convenience of description, and are not limited to any one position or spatial orientation. In addition, the modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). Unless defined otherwise herein, all percentages herein mean weight percent (“wt. %”). Furthermore, all ranges disclosed herein are inclusive and combinable (e.g., ranges of “up to about 25 weight percent (wt. %), with about 5 wt. % to about 20 wt. % desired, and about 10 wt. % to about 15 wt. % more desired,” are inclusive of the endpoints and all intermediate values of the ranges, e.g., “about 5 wt. % to about 25 wt. %, about 5 wt. % to about 15 wt. %”, etc.). The notation “+/−10%” means that the indicated measurement may be from an amount that is minus 10% to an amount that is plus 10% of the stated value. Finally, unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this disclosure belongs.
The present disclosure is directed to a cushioning material that is lightweight, comfortable, and provides significantly better shock absorption than many other cushioning materials. The cushioning materials of the present disclosure are well-suited to applications in which other cushioning materials, such as open cell foams, may be unsuitable due to their tendency to trap debris and moisture, and support the growth of microorganisms such as bacteria and fungi. The construction of the present cushioning materials prevents or minimizes moisture retention. In addition, the present cushioning materials can be made breathable, making them significantly more comfortable than many traditional cushioning materials, such as foamed plastics, for uses near the body.
Each cushioning element 12 comprises an upper surface 16 and a sidewall 18 extending upwardly from layer 14 to the upper surface 16, which together define an interior chamber 20. Upper surface 16 can be disposed substantially parallel to, or at an angle to layer 14, and sidewalls 18 can be disposed substantially perpendicular to or at an angle to layer 14. If desired, the cushioning elements 12 can comprise a radiused edge 13, as shown, which improves the cushioning characteristics of the material.
In any of the foregoing embodiments, if desired, a material and/or a device can be disposed in one or more of the chambers 20 in order to enhance the shock-absorbing characteristics of the cushioning material. Examples of the foregoing materials include, but are not limited to, woven or non-woven fabric, paper, polymeric materials, gels, foamed polymer material, combinations of the foregoing, and the like. Examples of the foregoing devices include, but are not limited to, resilient members such as springs, balloon-type devices filled with air, gel and/or fluid; combinations of the foregoing; and the like. For example,
If desired, upper surface 16 and/or sidewalls 18 can comprise one or more reinforcing members 15 disposed therein to increase the force required for deflection of chamber 20 and/or to provide greater stiffness for chamber 20. Reinforcing members 15 can be arranged in any desired pattern or arrangement in cushioning elements 12, and different geometries, size and/or orientations of the reinforcing members can be combined in order to achieve desired level of cushioning and comfort. For example,
In addition, perforations (not illustrated) can be disposed anywhere in cushioning material 10 in order to provide gas and/or fluid flow through the cushioning material.
Layer 14 can comprise a single material layer or a plurality of material layers, at least one of which comprises a polymeric material layer. The polymeric material can comprise any polymeric material with sufficient structural integrity to be thermoformed (including vacuum assisted thermoforming) into predetermined shapes; sufficient softness and/or pliability to provide comfort against a body; and that is capable of withstanding the environment in which it is intended to be used, without substantial degradation. The polymeric material can comprise a thermosetting polymeric material, a thermoplastic material, including a thermoplastic elastomeric material, and combinations comprising at least one of the foregoing. Some possible materials for the polymeric materials include, but are not limited to, polyurethane, silicone, olefins, vinyl polymers, ether amide, block copolyester, rubber, blends thereof, copolymers thereof, and combinations comprising at least one of the foregoing. Examples of some suitable materials include ethylene vinyl acetate (EVA), Kraton, etc.
The layers of material other than the at least one polymeric material also can comprise a polymeric material, and other materials such as, but not limited to, polymeric materials; knitted, woven or non-woven textiles; fabrics, including spacer fabrics; paper; metallic films; and the like, and combinations comprising at least one of the foregoing. The textile or non-woven layer or layers can be disposed on one or opposite sides of the polymeric material layer. In cases where antimicrobial active is in a surface textile or non-woven layer, it can also be present in the thermoplastic polymer layer beneath the textile or non-woven. If desired, any or all of the foregoing layers can comprise graphics such as logos and/or text printed thereon.
Layer 14 can comprise any thickness suitable for thermoforming, including vacuum assisted thermoforming. In some embodiments, the thickness of layer 14 can range from about 0.005″ (inch) to about 0.120″, more particularly about 0.020″ to about 0.090″, and more particularly still about 0.050″.
Any or all of the foregoing layers can comprise one or more additives such as, but not limited to, modifiers, coloring agents, stabilizers, phase changing materials, ultraviolet inhibitors, and/or active agents as well as combinations comprising at least one of the foregoing. The concentration of the additive can be varied depending on the desired effectiveness of the agent. One possible phase changing material can comprise phase changing microspheres (available under the product name OUTLAST), which contain materials that can change phases at near body temperature. As a result, heat energy can be stored, resulting in a product that can feel cool or warm.
Suitable active agents can comprise tolnaftate, undecenoic acid, allylamines, chlorine, copper, baking soda, sodium omadine, zinc omadine, azoles, silver, and/or the like, and combinations comprising at least one of the foregoing. For example, certain metals such as silver can provide an antifungal/antibacterial effect. For purposes of economy and effectiveness, it has been found advantageous to include active agents, when used, in the exterior layers of the cushioning material because they may come into contact with bacteria, fungus, etc. Disposing the active agents in the exterior surface layers of the cushioning material allows the use of reduced total amounts of the agents to achieve similar effective concentrations in comparison to the inner and/or thicker layers, thereby reducing costs associated with the additives. Also, disposing such agents in the exterior layers ensures that the agents are disposed in the outermost layer of the article i.e., the body contacting regions, rather than in regions remote from the user, which can increase the effectiveness of the agents.
In some instances, it may be desirable to use colorless and/or transparent materials for one or more of the layers, which can be desirable for aesthetic reasons. For example, when it is desirable to include color, graphics and/or text, it can be desirable to use colorless and/or transparent polymeric materials in order to allow the color, graphics and/or text to be visible to a user.
Because the formed structure provides for cushioning through deflection of the cushioning elements rather than by compression of a foamed plastic, rubber or gel, the thickness of the polymer layer in the cushioning material can be significantly less than the thickness used in foamed plastic or rubber to obtain similar impact protection or cushioning. For example, the amount of cushioning obtained from a thermoformed cushioning material 10 formed from a polymeric layer(s) of about 0.060″ can be superior than the amount of cushioning obtained from, for example, a foamed polymeric material having a thickness of 0.5″. In one example, the thickness of the cushioning material 10 may be approximately 0.375″ when measured from the upper surface 16 to the bottom of the polymer layer 14 (i.e. corresponding to T1), but the actual thickness of the polymer layer 14 at any point in the structure can be the same or less than the starting film thickness. It is for this reason, at least in part, that layer 14 when perforated, mesh, or porous can pass gas and/or liquid more easily than foam structures, particularly thicker foam structures. An open cell foam cushion can breathe, but the air passes through a tortuous path of cells to reach the other side. This tortuous path creates insulation, or dead air space. It also traps moisture.
Air and/or water are unable to pass through the cells of closed-cell foams (e.g., cross-linked polyethylene, and the like). The closed cells in such foams behave more like a sheet of non-porous plastic. One way to allow air and/or water to pass through or “breathe” is to punch or cut holes in the foams, or otherwise perforate the foamed material. Since closed-cell foam products also cushion based on their compression, they are frequently used in thicknesses greater than 0.125″ and up to as much as 1,″ depending upon the application. Due to the thickness of such materials, very small holes tend to collapse and thus minimize or eliminate significant air or moisture movement. For example, if one were to perforate a 0.5″ thickness of cross-linked PE foam with many pin-sized holes, such a perforated foam would still not feel comfortable against the skin, since these holes may not be capable of allowing air and/or water to move through the 0.5″ foam. Holes with a larger diameter (e.g. about 0.125″—the size of an eraser), can be more effective for air and/or moisture movement in these foams. However, perforating the PE foam with many larger holes of such a size can significantly impact its cushioning capabilities, since the foam functions by compression, and a large percentage of the foam surface area may not be able to share the compression load (i.e., the perforated portions). In contrast, the present polymer layer 14 can comprise, for example, a porous open mesh, and can still provide desirable cushioning properties since deflection, rather compression, is used for its cushioning.
If desired, cushioning material 10 can be made porous in order allow the transmission of air and/or fluid from one side of the material to the other. For example, the layer can be made porous by perforating the polymeric layer 14 before or after thermoforming; the polymeric layer 14 can comprise a mesh; or it can be a porous material prior to its thermoforming. As noted above, unlike perforations in closed cell foam structures, the perforations in the polymer layers used in the present materials can be quite small and close together in comparison, while allowing substantial and consistent air and/or moisture movement through the perforations. The polymer layer 14 can also comprise a microporous polymer structure where the pores or holes are sufficiently small to prevent the passage of liquid from a first surface to a second surface, and sufficiently large to allow the passage of a gaseous material (e.g., water vapor), to pass therethrough. In addition, the cushioning material 10 can be constructed from non-porous or porous layers that are also able to transmit moisture by means of a chemical adsorb/desorb process. Such materials include certain thermoplastic polyurethanes, block co-polyesters such as HYTREL, and other moisture transmittable polymers, including moisture transmittable nylon materials (e.g., PEBAX, and the like).
In addition, the use of moisture-breathable or adsorb/desorb polymer layers or porous structures such as perforated, slit, mesh or microporous materials together with the appropriate thermoformed pattern of indentations can create comfort through the ability to move moisture and/or air away from the user. The use of an appropriate textile layer can further be used to control the micro-climate between the cushion component and the user. Because the surface of the present cushioning material is full of indentations, rather than flat, there is the opportunity to in many cases allow for greater airflow when it is positioned in close proximity and/or direct contact with the skin of a user.
Any and all of the foregoing cushioning materials 10 and/or combinations of materials and/or devices can be used to form cushioning materials according to the present disclosure.
If desired, sheets of two or more of the same or different cushioning materials can be combined in a variety of arrangements in order to enhance the cushioning characteristics of a material and/or structure. In this way, the characteristics of the cushioning material can be tailored in products that may have varying cushioning requirements within the same product. Sheets of the same or different cushioning materials can be disposed adjacent to one another in a nested arrangement and/or a stacked substantially planar arrangement. In any of the foregoing embodiments, additional materials and/or devices can be disposed in any or all of the interior chambers in order to further tailor the characteristics of the cushioning material and/or to vary the cushioning and/or resiliency within the material and/or product. Examples of suitable materials include, but are not limited to, those discussed above such as woven or non-woven fabric, paper, polymeric materials, gels, foamed polymer material, combinations of the foregoing, and the like. Examples of suitable devices include, but are not limited to, those discussed above such as resilient members such as springs, balloon-type devices filled with air, gel and/or fluid; combinations of the foregoing; and the like. For example, stacked and/or nested arrangements, a gel and/or a resilient member can be disposed in any or all of the interior chambers of any or all of the sheets of cushioning materials. In addition, the durometer of materials disposed in the interior chambers can be graduated in order to provide varying cushioning characteristics within a cushioning element. The adjacent sheets of cushioning material also can comprise materials with different materials i.e., the durometer of a gel disposed in the interior chamber of an upper sheetcan be softer than the durometer of a material disposed in the interior chamber of a lower sheet.
Another embodiment of a cushioning material 500 in accordance with the present disclosure is shown in
If desired, the foregoing cushioning materials, either as a single sheet or as stacked and/or nested arrangements also can be disposed in a contoured product. For example,
As shown in
The formation of the cushioned articles of the present disclosure is facilitated by a method for thermoforming involving disposing a sheet of polymeric material between a pair of heated opposing male/female molds, which may be contoured or substantially planar, closing the molds for a sufficient period of time and at a sufficient temperature to allow the polymeric material to conform to the mold, cooling the mold, and removing the thermoformed article. The opposing male/female molds can comprise a substantially contoured pattern, such that the resulting contoured article comprises regions 14 lying in intersecting planes. If more than one layer is used, then the layers can be laminated together prior to molding, or they can be disposed into the mold at the same time as the polymeric layer. If a gas and/or liquid transmissible cushioning material is desired, a gas and/or liquid transmissible material can be used and/or a porous or mesh polymeric layer (and additional layers, if used) can be used. Alternatively, a nonporous material(s) can be thermoformed, and the resulting non-porous cushioning material can be perforated thereafter. If desired or necessary, stretch fabrics can be used in order to provide optimum results in the thermoforming process when introduced prior to thermoforming.
In use, upon the application of a force to the article, the impact will be absorbed by cushioning elements 12, which will deform in a direction that is substantially perpendicular to each of the upper surface 16. Upon release of the force, the cushioning elements 12 will bounce back to their initial shape.
The formation of the cushioning material(s) 10 of the present disclosure is facilitated by a method for thermoforming. As shown in
In another embodiment, the press can be an indexing press, and may include opposing male/female molds corresponding to the desired cushioning material 10. Thus, in this embodiment, instead of a continuous feed of the source material(s) 28,30, the source material(s) 28,30 can be fed into the press 950 on a start/stop basis. In this manner, a portion of the heated source material(s) 28,30 may reside in the forming station 36 for a sufficient period of time and at a sufficient temperature to allow the source materials to be molded to the desired shape. After thermoforming, the next portion of source material(s) can be indexed into the forming station while drawing additional source material(s) from the rollers and through the optional printing station 32, heating station 34, and into the forming station 36. Optionally, the source materials may be fed into and through an accumulator (not illustrated) that is designed to take up slack in the feed while the press is cycling. Also, optionally, the indexing press molds can be designed to travel with the moving web at the same speed as the web while the thermoforming cycle is taking place. After cycling, the indexing press molds can travel back to their original position in preparation for molding the next section of web.
In another embodiment, the polymeric material 28,30 can be extruded in-line with either the continuous thermoformer or the indexing thermoformer. With in-line extrusion, it is possible to run the process with less heat or possibly no heat since the film will be already be hot as it comes out of the extruder. Because of the reduced heat requirement, the process could in some instances run more rapidly than the methods above wherein the film must be brought to melt temperature in the forming step. In such cases, an accumulator (not illustrated) may be necessary to feed the polymeric film from the extruder to the thermoformer. This will allow the extrusion process to produce film on a continuous basis, while allowing the forming station to cycle.
In either embodiment, one of the sheets of material can be fabric fed into the process prior to or during the forming step, thereby producing a continuous cushioning material incorporating a fabric or multiple fabric layers. In general, the use of fabrics that are stretchable may be advantageous due to the fact that the stretch can accommodate the formation of the indentations/cushioning elements.
When more than one sheet of material is used, the multiple sheets of material may be fed into press 950 simultaneously with the at least one polymeric sheet, as shown in
Optionally, any of the source materials can be printed i.e., they can comprise color, graphics and/or text printed on one or both surfaces, and more than one sheet of material film may be joined during the process. Optionally, the method can comprise continuously printing one or more layers of the source material prior to feeding into the press, as shown. Alternatively, the source of material(s) can be a source of preprinted material, eliminating the need for the printing station.
In the case of multiple sheets of printed source material, the layers may be disposed such that the printing is disposed between polymeric layers in the finished product, which increases the durability of the printing. Otherwise, printing on a non-exposed side of the finished cushion will be more desirable for durability of the finished product.
Also optionally, any of the source materials can comprise additives, such as antimicrobial active agent, providing a finished cushioning material that is resistant to bacteria or fungi.
Also optionally, any of the source materials can comprise a breathable material such as a perforated or mesh material or a microporous material. Polymer mesh materials are available from a number of sources. Pre-cast films can also be perforated or slit prior to forming. In addition, the finished thermoformed sheet material may be perforated after thermoforming as a subsequent in-line step in the process, or can be perforated off-line as a separate process.
Various textile layers can be introduced into the process as the materials feed into the press. It is often desirable to have a surface layer of textile for aesthetic or comfort reasons, especially when the cushion material will be used against the skin. Unlike flat sheets of foam materials used in other cushioning products, it is somewhat difficult to bond to the convoluted surface of the film after the forming step. Therefore, it is desirable to feed the textile or textiles with the polymeric layer into the press prior to forming. It is possible to bond to the cushion sheet after forming, but fabric bonded in such a manner may not fully conform to the desired shape of the cushioned material 10, and may bridge between the individual cushioning elements 12. Such bridging may be desirable in some cases for aesthetic reasons or to allow better airflow beneath the textile layer.
The same options exist with respect to introducing textiles and antimicrobials in any of the above embodiments. For the in-line extrusion process, printing the film prior to forming would require cooling the film at this point in the process, and this would take away some efficiency. Creating a porous film in the direct extrusion process would most likely involve either perforating as a step subsequent to thermoforming, or in a post process. In addition, moisture transmissible resins could be used in the extrusion process, allowing for a finished product that can transmit moisture vapor without a porous structure.
The present cushioning material is lightweight, comfortable, and can offer significantly better shock absorption than many other cushioning materials. In addition, the cushioning materials of the present disclosure are well-suited to applications in which other cushioning materials, such as open cell foams, may be unsuitable due to their tendency to trap debris and moisture, and support the growth of microorganisms such as bacteria and fungi. The present cushioning material does not retain moisture and can be made to be breathable, making it significantly more comfortable than many traditional cushioning materials, such as foamed plastics, for uses near the body. The present cushioning material does not have a cellular structure and therefore can be more readily laundered without trapping debris and waste products from bodily sweat as is the case with many tradition foam cushion systems, making it ideal for sports protective padding, helmet linings, medical pads and braces and seating applications as well as many other uses. The method of making the material provides an economical, continuous sheet process to produce a shock absorbing cushioning material that is lightweight, and much less susceptible to contamination by sweat than conventional cushioning. The present cushioning materials can comprise fabrics and/or graphics to further enhance the comfort and aesthetics of the material and/or products made from the material.
While the disclosure has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.
Priority is hereby claimed to U.S. Provisional patent application Nos. 60/883,122, filed on Jan. 2, 2007; 60/883,123 filed on Jan. 2, 2007; 60/883,118, filed on Jan. 2, 2007; 60/883,309, filed on Jan. 3, 2007; 60/889,610 filed on Feb. 13, 2007; 60/889,618 filed on Feb. 13, 2007; 60/889,628 filed on Feb. 13, 2007; 60/889,634 filed on Feb. 13, 2007; 60/913,825 filed on Apr. 25, 2007; each of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
60883122 | Jan 2007 | US | |
60889610 | Feb 2007 | US | |
60883123 | Jan 2007 | US | |
60889618 | Feb 2007 | US | |
60883118 | Jan 2007 | US | |
60889628 | Feb 2007 | US | |
60913825 | Apr 2007 | US | |
60883309 | Jan 2007 | US | |
60889634 | Feb 2007 | US |