Waterproof shoe

BACKGROUND OF THE INVENTION

[0001] 1. Field of Invention

[0002] This invention relates to a waterproof shoe constructed from a waterproof, water vapor permeable layer.

[0003] 2. Description of Related Art

[0004] Shoes made from waterproof, water vapor permeable materials are well known. Waterproof, water vapor permeable shoes may be manufactured using a variety of materials and processes. Typically, waterproof, water vapor permeable shoes are manufactured using a laminate material to impart waterproof, water vapor permeable characteristics to the shoe. The laminate material is often used in conjunction with other materials, well known in the art, that provide the exterior portions (such as, for example, the upper or the sole) and interior portions of the shoe (such as, for example the lining). The laminate material used to impart waterproof, water vapor permeable properties to the shoe is typically made from a functional layer, which imparts the waterproof, water vapor permeable characteristics, and at least one more layer of other materials or textiles.

[0005] The construction of waterproof, water vapor permeable shoes from a laminate material is very expensive and labor intensive, as nearly every seam that is sewn in the process of making the shoe must be resealed to attempt to maintain a waterproof, water vapor permeable shoe.

[0006] Various types of waterproof, water vapor permeable shoe designs are known. A first common method is to simply construct the shoe from known materials in conjunction with waterproof, water vapor permeable materials (i.e., a waterproof, water vapor permeable laminate) and perform the aforementioned requisite seam sealing using a seam sealing tape, glue or other process to maintain a waterproof shoe design. A second common method to manufacture waterproof, water vapor permeable shoes is to manufacture a waterproof, water vapor permeable sock-like liner which is subsequently inserted and attached to the remainder of the shoe. The three dimensional sock-like liners are manufactured from a waterproof, water vapor permeable laminate and require extensive sewing to create a three dimensional sock-like liner out of a flat sheet of the laminate. Every seam that is sewn to create the sock-like liner must be resealed to attempt to the maintain waterproof, water vapor permeable characteristics of the shoe.

[0007] A waterproof, water vapor permeable laminate may be manufactured by gluing together at least two layers, for example, a functional layer and a second layer made from a textile fabric or other material. The functional layer is typically the waterproof, water vapor permeable layer. The second or subsequent layers are generally water vapor permeable and not waterproof. At the areas where glue is located between the functional layer and second layer, the glue hinders the water vapor permeability of the laminate. Therefore, in the manufacture of laminates, efforts have focused on gluing the functional layer and the second layer together only at points necessary to maintain the integrity of the laminate. However, significant areas still remain where glue covers the functional layer, and at these points, the functionality of water vapor permeability is reduced or eliminated.

[0008] It is often difficult to guarantee waterproofing and water vapor permeability in either of these type of shoe designs, even when the seams have been resealed, because every seam which is sewn into the laminate can transport water to the inside of the shoe via capillary action. Furthermore, the use of sealant often detracts from the waterproof, water vapor permeable design of the shoe because the sealant, such as tape or glue, is not typically waterproof, water vapor permeable. Portions of the shoe in which sealant are applied typically lose their waterproof, water vapor permeable properties.

[0009] Using either of these above-described methods to manufacture waterproof, water vapor permeable shoes also requires that different sized liners be manufactured to obtain different sized shoes. Requiring a different sized liner for different sized shoes increases production costs.

[0010] There are illustrated in WO 95/30793 waterproof, breathable, flexible, seamless shaped articles made from a first layer of a microporous, elastomeric, thermoplastic polyester polyurethane or polyether polyurethane that is water vapor permeable and a second layer of a hydrophilic, continuous non-porous polymer layer that is waterproof and water vapor permeable.

[0011] There is illustrated in EP 0 665 259 A1 a process for manufacturing waterproof, water vapor permeable three dimensional articles made by treating a 3-dimensional mold with an aqueous dispersion of a copolyether ester at least once in a manner, analogous to that employed for a latex dispersion in the rubber industry, followed by heating to obtain a film.

[0012] There is illustrated in U.S. Pat. No. Re. 34,890 a shoe construction comprising a sole, an upper and a separate sock-like liner comprised of a laminate of at least three layers. The liner may be secured by stitching and thereafter covered with tape and a thermoplastic resin adhesive. Heat and pressure are then applied to the seam of the liner covered with tape and adhesive. This process waterproofs the stitching of the seam of the liner. The seams of this invention may also be formed without stitching instead using electro-disealing and adhesives.

[0013] As described above, there is still a need for a waterproof, water vapor permeable shoe design that overcomes the above-described obstacles.

SUMMARY OF THE INVENTION

[0014] It is an object of the invention to provide for a waterproof, water vapor permeable shoe design that avoids problems of laminated layers and reduces the necessity to seal the seams in the waterproof, water vapor permeable portions of the shoe.

[0015] It is a further object of the invention to provide a more economical and efficient waterproof, water vapor permeable shoe design by reducing the necessity for various sized liners and for a reduction in the time spent in the process of manufacturing the liner.

[0016] These and other objects of the present invention are achieved herein. In the invention, a waterproof, water vapor permeable shoe is manufactured from the incorporation of a waterproof, water vapor permeable functional layer into the shoe design. The sock-like functional layer is not attached to the liner except at the top opening of the shoe, i.e., the upper portion of the upper. The sock-like functional layer is separate from the lining and the upper and is not a laminate. The waterproof, water vapor permeable functional layer may be formed from a solution or a dispersion of a waterproof, water vapor permeable polymer.

[0017] The shoe construction of the present invention provides a waterproof, water vapor permeable shoe with no or a reduced risk of losing its waterproof, water vapor permeability. The shoe construction of the present invention accomplishes these objectives by providing for a seamless or virtually seamless functional layer that obviates or reduces the need for seams or seam-sealing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]
FIG. 1 is a cross-sectional view from the side of the shoe.

[0019]
FIG. 2 is a cross-sectional view from the side of the shoe having an injection molded sole.

[0020]
FIG. 3 is a view from the bottom of the sock-like functional layer showing a cut in the bottom of the functional layer.

[0021]
FIG. 4 is a view of the cut ends of the functional layer being connected.

[0022]
FIG. 5 is a view of the cut ends of the functional layer being connected with glue over tape.

[0023]
FIG. 6 is a view from the front of a the sock-like functional layer in which the bottom of the functional layer has been removed and replaced with an insole.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0024] The present invention provides a waterproof, water vapor permeable shoe design in which a waterproof, water vapor permeable functional layer is formed from a dispersion or solution of waterproof, water vapor permeable polymer. The functional layer is in the shape of a sock and is then is incorporated into the shoe.

[0025] The present invention provides a waterproof, water vapor permeable shoe design comprising 1) a waterproof, water vapor permeable functional layer produced by dipping a foot shaped, solid form into a dispersion or a solution of waterproof, water vapor permeable polymer and allowing the form to dry and harden and then peeling the sock-like functional layer from the form, and 2) attaching the functional layer to the lining of a shoe wherein the attachment is at least at the opening of the shoe.

[0026] The sock-like functional layer is inserted into the upper material, a lining is inserted into the functional layer, and finally a sole is incorporated onto the bottom portions of the upper material and/or the functional layer. The functional layer may only be connected to the lining near the opening of the shoe. Optionally, the lining may be inserted into the functional layer, before the functional layer is inserted into the upper.

[0027] In other embodiments, the present invention provides a shoe construction where, prior to insertion into the upper, an opening may be cut into the bottom of the functional layer to further increase the adaptability of the functional layer. Once an opening has been cut into the functional layer, portions of the functional layer may be removed from the opening and the edges of the opening may then be reconnected. By removing portions of the functional layer, a smaller-sized functional layer is made without using different sized forms. Additionally, once an opening has been made in the functional layer, an insole may be inserted into the opening to increase adaptability of the functional layer.

[0028] The present invention provides a process for manufacturing waterproof, water vapor permeable shoes by forming a functional layer from a dispersion of a waterproof, water vapor permeable polymer, inserting the functional layer into an upper, inserting a lining into the functional layer, and attaching the functional layer to the lining at least at the top opening of the shoe. Optionally, the lining may be inserted into the functional layer before the functional layer is inserted into the upper.

[0029]
FIG. 1 shows a shoe of the present invention having an upper 1, a functional layer 2, a lining 3, and a sole 5. The functional layer 2 is waterproof and water vapor permeable and is situated between the upper 1 and the lining 3.

[0030] The functional layer 2 is preferably attached only at the top portion of the upper 1, i.e., the top opening where a foot of a wearer is inserted into the shoe. In a preferred embodiment, the portion of the upper near the opening of the shoe shown in FIG. 1 is folded over the ends of the functional layer 2 and the lining 3 and fixed over a seam 4. This connection between the functional layer 2 and the lining 3 near the opening of the shoe is preferably the only connection between the functional layer 2 and the lining 3.

[0031] The functional layer 2 is in the shape of a sock and is not bonded with the lining with the exception of at the opening of the shoe. At the bottom of the shoe, the upper 1 is bonded to the sole 5, preferably over a seam and/or over a glue. The part of the functional layer adjacent to the sole may be bonded, preferably using glue or a sewing technique, to the sole. If the functional layer is sewn to the sole, the outer contour of the sole may be sewn to the functional layer and the holes in the functional layer may be resealed by another application of waterproof, water vapor permeable polymer.

[0032] In another embodiment of the present invention, injection molded shoe designs are possible. See, for example, U.S. Pat. No. 5,930,917, incorporated by reference herein. FIG. 2 shows a construction of a shoe of the present invention whereby the sole 6 is injection molded. In the case of injection molded soles, the material that is injected to form the sole may fill and seal any seams or other breaches (caused by manufacturing) in the waterproof, water vapor permeable functional layer. Therefore, the seams caused by a cut in the functional layer, either to increase size adaptability or to insert an insole, may not require further glue and tape to maintain waterproofness. In this construction, the functional layer 2 is bonded to the injection molded material.

[0033] Surprisingly, a separate form is not necessary for every shoe size or style because of the relative thinness of the functional layer. When the functional layer is incorporated into a shoe, the folds and creases the functional layer makes as it conforms to the interior portions of the shoe are not noticed by the wearer of the footwear since the material forming the functional layer is relatively thin, i.e., 10 to 150 microns. One particular size functional layer may be incorporated into many different sizes of shoes. This interchangeability of the functional layer reduces manufacturing costs as a separate sized liner is not required to be manufactured for each individual shoe size.

[0034] The upper 1, lining 3, and the sole 5 may be selected from materials well known in the art. See, for example, U.S. Pat. No. 5,678,326, incorporated herein by reference. The upper 1 may be made from, for example, leather, textiles, woven fabrics, canvas, fabric, chintz, everglaze, terry, velvet, Manchester velvet, corduroy, velveteen, Norzon, leatherette, muslin, duvetine, satin, fur, imitation fur, suede leather, satin finish leather, patent leather or polished, embossed, shrunk or grained leather.

[0035] The lining 3 may be made from, for example, terry, goat skin, sheep skin, cowhide, pig skin, velvet, camel hair, fabric, knitted or woven fleece, woven fabrics, cotton, wool, synthetic fibers, and/or cellulose materials.

[0036] The sole 5 may be made from waterproof materials such as, for example, rubber, polyurethane, polyvinyl chloride and their derivatives, and mixtures of the same.

[0037] The functional layer of a waterproof, water vapor permeable laminate may be manufactured from polymers which are suitable for forming a microporous polymeric matrix. See, for example, U.S. Pat. No. 5,732,479, incorporated by reference herein its entirety. Suitable polymers include polyolefines, such as polyethylene-propylene copolymers, polyethylene, terephthalates, polycaprolactam, polyvinylidenefluoride, polybutyleneterephthalate, polyester copolymers and polytetrafluoroethylene. A waterproof, water vapor permeable functional layer may also be a coating or an impregnation or a membrane of the aforementioned polymers on a copolyether ester base, or may be made of oriented polytetrafluoroethylene, preferably with a microporous polyurethane coating (Gore-tex). Polymers of a copolyether ester base (Sympatex) have proved to be excellent materials for this purpose due to their properties of high water vapor permeability, high waterproofness and wear resistance.

[0038] The waterproof, water vapor permeable functional layer, also referred to herein as “the functional layer”, is preferably formed by dipping a form into a solution or dispersion of a waterproof, water vapor permeable polymer and allowing the polymer to harden, and then peeling the functional layer from the form. The dipping process may be repeated several times. After dipping and before removal from the form, the polymer dispersion on the form may be heated, causing the polymer to melt and form a continuous film. The form may roughly be in the shape of a human foot or other three dimensional, solid article that would confer a sock-like shape to the functional layer. Manufacture of the functional layer may be accomplished using the methods and materials as described in EP 0 665 259 A1 or in WO 95/30793, both of which are incorporated herein by reference in their entireties.

[0039] The waterproof, water vapor permeable polymer solution or dispersion may contain copolyether esters obtained by copolymerizing an aromatic dicarboxylic acid or ester forming equivalent thereof with a dioic acid molecular weight of not more than 300, a diol or ester forming equivalent thereof with a dioic molecular weight of not more than 250, and a polyalkylene oxide glycol with a molecular weight in the range of 600 to 4,000 and an atomic ratio of carbon to oxygen in the range of 2.0 to 4.3 with at least 20% by weight of the long chain glycol having a carbon to oxygen ratio in the range of 2.0 to 2.4 and 15% to 50% by weight being part of the copolyether ester. The aromatic dicarboxylic acid preferably is terephthalic acid or napthalene dicarboxlyic acid, while the low-molecular weight diol preferably is ethylene glycol or butane diol. In addition, preference is given to a polymer having a melting point of at least 150° C. See for example, EP 0 665 259.

[0040] The sock-like functional layer may be made by dipping the form into more than one dispersion or solution of polymers that each possess different qualities to provide and/or improve the waterproof, water vapor permeable characteristics of the sock-like liner. By using different solutions or dispersions, a composite sock-like functional layer may be formed. The first layer of the composite may be a microporous, elastomeric, thermoplastic polyester polyurethane or polyether polyurethane that is water vapor permeable. The second layer or subsequent layers of the composite may be a non-porous layer that is hydrophilic, waterproof, and water vapor permeable. The second layer or subsequent layer may improve the waterproofness and/or water vapor permeability of the first layer or impart other desired characteristics, such as wear resistance. The preferred polyurethanes for the first layer are elastomeric polyurethanes based on a linear, hydroxyl terminated polyester (although a polyester polyol or a polyether/polyester blend may be used) and a diisocyanate, with a small addition of a difunctional low molecular weight reactant.

[0041] The second hydrophilic polymer layer of the composite may be made from hydrophilic elastomers such as, for example, polyesters, polyamides, cellulose derivatives, polyacrylic acid and its homologs, natural or synthetic rubber with hydrophilic impurities, copolyoxamides, polyureas, polyelectrolytes, polyphosphates, polyvinylamines, polyvinylalcohol, polyether and copolymers thereof; polythioether, polythioether-polyether, copolyepichlorohydrinether, polysulphosphates, copolyesterether and derivatives or mixtures thereof Preferably the hydrophilic polymer is a copolyether ester, polyurethane or a copolyetheresteramide. All of these polymers are permeable to water vapor, but are highly impervious to liquid water. See, for example, WO 95/30793, herein incorporated by reference in its entirety.

[0042] The sock-like functional layer may have a thickness of, for example, about 10 to 150 microns. Preferably, the functional layer has a thickness of, for example, about 40 to 100 microns. The sock-like functional layer may be formed dipping, spraying or any other process, well known in the art, of applying a dispersion or solution to a form or three-dimensional article.

[0043] In another embodiment of the present invention, the adaptability of the functional layer may be increased by cutting an opening in the bottom of the functional layer 2. As shown in FIG. 3, by making a cut in the bottom of the functional layer, for example, along line 7 and thus forming cut ends 13a and 13b as shown in FIG. 4, it is possible to adapt the shape of the functional layer 2 to a variety of shoe sizes. As shown in FIG. 4, the cut ends 13a and 13b of the functional layer 2 may then be bonded together with glue and/or with a seam 8. As shown in FIG. 5, the connection between the cut ends 13a and 13b may be made watertight by tightening the cut ends 13a and 13b over a tape 9 and over glue 10. If cut ends 13a and 13b are too long after rejoining, removing a portion of the functional material along the cut or cutting the excess length of the cut ends may provide for a smaller sock-like functional layer, further increasing the adaptability of the sock like liner to an even greater variety of shoe sizes.

[0044] In another embodiment, an insole 11 may be incorporated with the sock-like functional layer. As shown in FIG. 6, the functional layer 2 is cut out in the bottom area (i.e., the surface of the functional layer which would have been adjacent to the sole) and removed. The ends of the functional layer, made by cutting out the bottom area, are preferably bonded to the edges of the insole over seams 12. The connection between the functional layer and the insole may be made waterproof if the ends of the functional layer and the insole are connected in a manner analogous to FIG. 5, i.e., the functional layer and the insole are connected over glue and tape. The functional layer, insole and upper may be joined to the sole by, for example, gluing, sewing, adhesives, injection molding, or other techniques.

[0045] The functional layer, after having an insole inserted, a cut made along line 7 to increase the adaptability of the shoe, or other modification which might have breached the waterproof, water vapor permeable properties of the shoe, may have the solution or dispersion of waterproof, water vapor permeable polymer reapplied to the functional layer to regain or improve the waterproof, water vapor permeable properties of the functional layer.

[0046] As shown in FIG. 1, the glue used to attach the bottom of the shoe to the upper and functional layer may provide a sealant for the any seams between the sole, the upper and the functional layer. This glued connection may also seal any seams or breaches in the functional layer created from having an insole inserted., a cut made along line 7 to increase adaptability or other modification. It is also possible to first glue the seams between the functional layer and the upper to make the seams watertight and then to glue the sole to the bottom of the upper and the functional layer.

Waterproof shoe

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