Patent Application
20130055598
The art is replete with attempts at making waterproof, breathable footwear. Early attempts for making such footwear included making footwear consisting of upper materials such as leather treated to make it water resistant and soles made of rubber. Thus, some breathability was achieved. However, several problems arose with this type of footwear construction. If the upper material was to be made truly waterproof, it would lose its ability to breath. Moreover, the connecting region between the waterproof sole and the upper became a major source of leakage as there was no effective way to make the connecting region waterproof.
An alternative approach to the goal of achieving comfortable waterproof footwear involved employing a waterproof insert or bootie into the shoe. This method is particularly useful in machine lasted footwear, as known in the art. This waterproof insert, if constructed of appropriate materials had the additional advantage of being permeable to water vapor so that there was no buildup of water vapor within the shoe over the time when the shoe was being worn. In the footwear art materials which are both waterproof and water vapor permeable are commonly referred to as “functional” materials. Exemplary of such a functional material is a microporous, expanded polytetrafluoroethylene membrane material available from W. L. Gore and Associates, Inc., Elkton, Md., under the tradename GORE-TEX®. Other functional materials have also been developed and are well known in the art.
Further approaches have included securing, by a lasting process, a waterproof, breathable liner material to the inside of the footwear upper and sealing the liner material to a waterproof gasket or insole. There have been many different attempts at providing a durable, waterproof seal or connection at the region where the liner material is joined with the waterproof gasket or insole. These attempts have resulted in varying degrees of success.
One problem which often results when forming such waterproof, breathable footwear is that the insertion of the liner or bootie will often result in a poor fitting shoe (i.e., a smaller fit due to the liner being inserted into the already sized shoe upper) and/or poor attachment between the liner or bootie and the shoe upper material, which results in, among other things, a less than desirable appearance of the inside of the footwear (i.e., the liner appears wrinkled or pulls away from the upper).
An additional problem is that utilization of traditional waterproof gasket in footwear constructions is economically inefficient because it adds an additional processing step to achieve waterproofness.
Thus, the search continues for durably sealed, waterproof, breathable, gasketless footwear that is both flexible in use and economical to manufacture.
Waterproof, breathable shoes having an upper assembly, and a sole assembly are described herein. The upper assembly includes upper and lower portions, each of the upper and lower portions having an outer material and a breathable layer or layers which make up a bootie and that includes at least one waterproof functional layer. The lower portion of the upper assembly further includes a non-functional means of retaining the shape of the upper assembly. The non-functional means is connected to the breathable layer or layers that include at least one waterproof functional layer.
Further the sole assembly includes an outer sole comprising a lower portion of the outer material and the breathable layer or layers of the upper interspersed therein. It further includes a means of facilitating the flow of polymer throughout the sole assembly to adhere the sole assembly and the lower portions of the upper assembly together to form a waterproof seal.
In alternate embodiments, the means for facilitating the flow of polymer may be a spacer material, an insole, or a spacer material/insole composite. The non-functional means may be a strobel board or an elastic material, or a textile, or may be string lasted.
The breathable layer or layers may further comprise one or more additional layers adapted to form a laminate with the waterproof functional layer or layers.
The waterproof functional layer or layers may be composed of polyurethane, polyester, polyether, polyamide, polyacrylate, copolyether ester, copolyether amides, polyetetrafluoroethylene, combinations thereof, or the like.
In an additional embodiment, a waterproof, breathable shoes having an upper assembly, a midsole and an outsole are described herein. The upper assembly includes upper and lower portions, each of the upper and lower portions having an outer material and a breathable layer or layers which make up a bootie and that includes at least one waterproof functional layer. The lower portion of the upper assembly further includes a non-functional means of retaining the shape of the upper assembly. The non-functional means is connected to the breathable layer or layers that include at least one waterproof functional layer.
The midsole comprises a lower portion of the breathable outer material of the upper interspersed therein and a means of facilitating the flow of polymer throughout midsole to adhere the midsole and the lower portions of the upper assembly together to form a waterproof seal.
The outsole is adapted for attachment to the midsole.
The invention relates to waterproof footwear and methods for making the same. Unlike traditional WPB machine lasted footwear, the disclosed inventive footwear constructions are gasketless. That is, the inventive footwear contains a functional liner that is gasketless or that does not have functional material across the entire bottom of the bootie. Instead it provides space between at least a portion of the upper assembly 10 and at least a portion of the sole assembly 20 so that a means for facilitating the flow of polymer 100 facilitates the flow of polymer or other adhesive through the means in order to provide a seal between the upper assembly and sole assembly. Additionally, the polymer or other adhesive can be used to formulate an optional midsole 240 so that outsole can be later attached by methods known in the art, or it can be utilized to formulate a complete outsole as part of the sole assembly. Because a traditional gasket or full bootie is not used, this results in improvements in factory production including materials, labor, energy, and inventory as well as productivity improvements, specifically a reduction in manufacturing steps, floor space, and total production time.
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The liner material will contain at least the above described functional material 70 and at least one other material 60 laminated thereto. In this regard, the liner can include the functional material and a textile material (desirably breathable) laminated or otherwise joined to at least one side, and often times joined to both sides thereof. Lamination is generally carried out with the use of a discontinuous pattern of suitable adhesive. Thus, water vapor permeability is not significantly effected. At least one other material can be a textile fabric. Textile fabrics can be woven, knit, mesh, nonwoven, felt constructions, etc. Textiles can be produced from natural fibers such as cotton, or from synthetic fibers such as polyesters, polyamides, polypropylenes, polyolefins, or blends thereof. In an aspect of the invention a textile fabric is laminated to the side of the functional material which will be in contact with the outer material of the upper 50. In a further aspect of the invention a textile fabric is laminated to the side of the functional material which will face the inside of the footwear. In a still further aspect of the invention, textile fabric is laminated to both sides of the functional material, thus providing a three layer liner material. Suitable outer material of the upper includes leather, cordura, nylon, or the like.
Alternatively, the means for retaining the shape 80 of the upper assembly 10 could include a string lasted liner. That is, it could be composed of strips of material holding together the upper assembly without need for additional material.
Once the bootie is formed, a lasting process is carried out. Specifically, a shoe last, as known in the art, is inserted into the bootie at the open top portion 140 to form the bootie to the exact shape of the shoe last.
Typically, at this point, in prior art lasting processes when the shoe last is inserted into the bootie, a waterproof gasketing material is attached to the bottom surface portion of the bootie as part of a sole assembly.
It has been unexpectedly discovered, however that the attachment of a waterproof gasket material is not necessary.
In this regard, a means for facilitating the flow of polymer 100 throughout the sole assembly to adhere the sole assembly 20 and the lower portions of the upper assembly 40 together to form waterproof seal is placed at the bottom of the bootie for subsequent attachment. In one embodiment the means may be a spacer material, for example, a spacer mesh 110 cut into substantially the same shape as the bottom of the last. In another embodiment, the means may be an spacer material/insole board composite 130 substantially the same shape as the bottom of the last (i.e. the bottom of a foot). Any other suitable means may be utilized as long as it is sufficiently compression resistant to retain flow channels during an injection process and sufficiently stiff and bending to facilitate lasting of the upper. In another embodiment, the means may be a molded insole board 120 by itself. In all embodiments, the spacer material, insole board and/or the spacer material/insole board composite may have one or more opening contained therein to facilitate the flow of adhesive material throughout the sole assembly to create a waterproof seal. The openings may be holes, channels, or the like.
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Regardless of the type of adhesive used, the adhesive must by flowable to an extent that flow through the openings in means for facilitating the flow of polymer 100 to at least substantially fill those openings with polymer and adhere together the sole assembly and the lower portions of the upper assembly.
Thereafter, the upper assembly 10 is pulled down, cemented (or otherwise attached to the bottom of the means for facilitating the flow of polymer 100) and folded over to fix the shape of the shoe upper to the last. The spacer material is positioned to keep the insole out of complete contact with bottom of the bootie so that the adhesive is able to completely seal the bottom of the bootie once injected into the openings.
Molding compounds, as known in the art, are then applied through the openings utilizing convention methods known in the art, such as, for example injection molding, pour molding, etc.
Conventional steps can then be performed to attach a suitable outer sole material or outer sole/midsole to the bottom surface of the footwear, if required.
For completeness,
Conventional methods include injection or pouring of polymeric material utilizing conventional injection molding to form an outersole or a midsole. Alternatively, an outersole may be cemented or otherwise attached (stitching, partial stitching, stapling, welding, etc) to the bottom of the footwear construction following injection or pouring of polymeric materials.
What is meant by “waterproof footwear” is determined as follows. The footwear is placed on top of a piece of blotter paper. The inside of the footwear is filled with room temperature water to a height of about 30 mm below the top line of the functional material (measured from the insole at the heel area of the footwear). The water is allowed to stand in the footwear for at least two hours. At the end of the two hour period the blotter paper and footwear upper are examined to determine if water has reached the blotter paper or the outside of the upper. If no water has reached the blotter paper or the outside of the upper, then the footwear is waterproof.
As used herein the “waterproof, water vapor permeable functional layer” and the “waterproof gasket material” are “waterproof” if, when combined to form the footwear according to the invention, they result in the footwear being “waterproof” as defined above.
While particular embodiments of the present invention have been illustrated and described herein, the present invention should not be limited to such illustrations and descriptions. It should be apparent that changes and modifications may be incorporated and embodied as part of the present invention within the scope of the following claims.
