FOOTWEAR

The present invention is in the field of footwear. In particular, the present invention is in the field of waterproof, breathable footwear, providing an all around waterproof structure around the wearer's foot.

Waterproof shoes have been known for a long time. In recent years, waterproof and breathable shoes have been developed that provide for an all-around waterproof structure around the wearer's foot, but at the same time provide breathability, such that moisture and sweat from the wearer's foot can escape from the interior of the shoe. Such shoes commonly have an arrangement of various waterproof and breathable functional layers, also referred to as waterproof and breathable membranes, extending around the inner space of the shoe. For example, a lower functional layer underneath the wearer's foot may be combined with an upper functional layer on top and to the sides of the wearer's foot, with the two functional layers being joined along their periphery by a sewn seam. In this way, a waterproof and breathable bag around a wearer's foot may be provided. Previous approaches for waterproof and breathable footwear have not been fully satisfactory in terms of user comfort.

Accordingly, it would be beneficial to provide footwear that allows for an improved comfort to the wearer, while maintaining waterproofness and breathability.

Exemplary embodiments of the invention include footwear comprising an upper assembly having an outer construction and a bootie, and a sole attached to the upper assembly. The bootie is made with a waterproof, breathable laminate, the waterproof, breathable laminate comprising a one-piece functional layer and at least one textile layer. The bootie has elasticity in a circumferential direction of the bootie, the bootie is fixed in position in a toe region of the footwear and fixed in position in a heel region of the footwear, and the bootie is not attached to the outer construction on an upper side of a midfoot portion of the bootie.

Exemplary embodiments of the invention allow for an improved comfort for the user when wearing the footwear. In particular, the provision of the bootie with a one-piece functional layer and elasticity in the circumferential direction of the bootie, together with the freedom to move with respect to the outer construction on the upper side of the midfoot portion of the bootie, provides for an optimized compromise between a stable and non-disturbing feel of the footwear that also provides a perceived high level of freedom to move within the footwear. The fixing of the bootie in position in the toe region and the heel region of the footwear and the elasticity in the circumferential direction of the bootie provide for a well-defined stance of the user within the footwear and for an overall stable feel due to the elastic tightening of the bootie around the wearer's foot. While the attachment in the front and the back of the shoe and the elasticity in the circumferential direction of the bootie provide for support and a sense of stance safety to the wearer, the non-attachment to the outer construction on the upper side of the midfoot portion of the bootie provides for a high level of perceived freedom to move. It has been found that the potential for relative motion between the bootie and the outer construction on the upper side of the midfoot portion of the bootie leads to a high level of comfort and a feeling of not being confined by the footwear, while not compromising the wearer's feeling of stability. The described combination of attachment/non-attachment and the elasticity of the bootie provides for an optimized compromise between stability and freedom to move, thus increasing the wearer's comfort. The bootie having a waterproof, breathable laminate with a one-piece functional layer enhances all of the described effects. The one-piece nature makes the elasticity of the bootie immediately present around the wearer's foot, making the bootie feel stable and comfortable to the user. Also, the one-piece nature, leading to a bootie with at most one seam, leads to a very low or even entirely eliminated impairment of comfort, as will be described below.

The term bootie refers to a sock-like structure that encases the foot of the wearer, when inserted into the footwear. The bootie is generally arranged in the space between the outer construction of the upper assembly and the sole, i.e. in the inner space of the shoe. The bootie may also extend out of the inner space of the shoe at the collar region of the upper assembly. In other words, the bootie may extend upwards from the outer construction of the upper assembly. The bootie is made with a waterproof, breathable laminate. In this way, the bootie provides a waterproof and breathable sock-like structure all around the wearer's foot, with the exception of at most one seam, as will be discussed below. This waterproof and breathable bootie construction allows for the discharge of water vapor from the wearer's foot through the bootie and to the outside of the footwear via the outer construction and/or the sole.

The waterproof, breathable laminate comprises a one-piece functional layer and at least one textile layer. The one-piece functional layer and the at least one textile layer may be substantially co-extensive. The term at least one textile layer intends to state that the one-piece functional layer may be provided with a textile layer on one side thereof or with a textile layer on each side thereof, i.e. with two textile layers. It is also possible that more than one textile layer is provided on one side or on both sides. In addition, each textile layer may be made up of multiple textile pieces. For example, the waterproof, breathable laminate may comprise a one-piece functional layer and one textile layer on one side of the functional layer, with the one textile layer being made up of multiple textile pieces that are sewn together. In other words, the one-piece functional layer may be provided with one or more textile layers that are made up from originally separate textile pieces.

With the functional layer being a one-piece structure, the waterproof, breathable laminate is also considered a one-piece structure. This is irrespective of whether the textile layer is made of originally separate textile pieces or not. In case the textile layer is made of originally separate textile pieces, a one-piece laminate structure is present, at least at the point where the laminate is formed from the one-piece functional layer and the multiple textile pieces. Hence, the bootie is made from one continuous waterproof, breathable laminate and is also considered a one-piece structure. In particular, the bootie is made from a continuous waterproof, breathable laminate, which may be shaped to inherently have the form of a bootie or which may be cut, folded and sewn or glued together to form a bootie.

An exemplary construction method for a bootie in accordance with the former case is as follows. A textile layer may be formed from a plurality of textile pieces. The plurality of textile pieces may be sized and sewn together in such a way that a sock-like textile layer is formed. The sock-like textile layer may be placed on a last, and a functional layer may be stretched over the last and brought into contact with the sock-like textile layer. The functional layer is adhered to the textile layer and the waterproof, breathable laminate is thus formed. This waterproof, breathable laminate has the inherent shape of a bootie. Both the waterproof, breathable laminate and the bootie are considered seamless. The seams between the originally separate textile pieces, if present, are considered to be seams of a precursor product and are not considered seams of the laminate of the bootie. It is also possible that one or more of the at least one textile layer are seamless as well.

In the alternative of the cut, folded and sewn/glued laminate forming the bootie, a substantially flat waterproof, breathable laminate is provided, for example having a one-piece functional layer and a textile layer on one side, potentially made from originally separate textile pieces. The laminate is cut in such a shape that, upon folding the laminate, a sock-like shape is formed. The edges of the laminate are then sewn or glued together, such that the sock-like shape is retained.

The waterproof, breathable laminate may be a two-layer laminate consisting of the functional layer and a textile layer. The waterproof, breathable laminate may also be a three-layer laminate, with the functional layer being sandwiched between a first textile layer and a second textile layer on opposite sides of the functional layer. The waterproof, breathable laminate may also comprise one or more further layers, such as an additional water-stopping layer, keeping water off the functional layer and thus ensuring breathability thereof. The term functional layer is a commonly used term in the art of footwear and refers to a layer combining waterproof and breathable characteristics. Alternatively, a functional layer is also often referred to as a waterproof, breathable membrane.

The functional layer may include or may be a breathable and waterproof membrane. The membrane may be selected from polyurethane, polyester, polyether, polyamide, polyacrylate, copolyether ester and copolyether amides, as well as other suitable thermoplastic and elastomeric films. In a particular embodiment, the waterproof, breathable membrane may be made of a fluoropolymer, particularly made of microporous expanded polytetrafluoroethylene (ePTFE). The microporous polytetrafluoroethylene membrane is a membrane of expanded polytetrafluoroethylene as taught in U.S. Pat. Nos. 3,953,566 and 4,187,390, to Gore. Such membranes of expanded polytetrafluoroethylene are present in commercially available laminates from W. L. Gore and Associates, Inc., Elkton, Md., under the tradename GORE-TEX® fabric. The breathable and waterproof functional layer may be composed of a polyurethane coated microporous expanded polytetrafluoroethylene membrane made substantially according to the teachings of U.S. Pat. No. 4,194,041 and U.S. Pat. No. 4,942,214, assigned to W. L. Gore and Associates, Inc, in Elkton, Md.

The bootie is elastic in the circumferential direction thereof. In other words, when the wearer inserts a foot into the footwear, the bootie is able to stretch and to expand elastically in order to make room for the foot of the wearer. In this process, the bootie conforms to the foot of the wearer, it is therefore also referred to as a conformable bootie. The bootie being elastic means that it exerts a force against the wearer's foot upon insertion thereof. In other words, the elasticity builds up a force that forces the bootie towards its shape before insertion of the wearer's foot. This force provides for a recovery of the bootie towards its previous shape after exertion of the wearer's foot. The elastic nature of the bootie may be achieved in any suitable way. Particular examples of producing elastic laminates are given in WO 95/32093 A1, the contents of which is incorporated herein by reference in its entirety.

The bootie is elastic in a circumferential direction thereof. This expression does not require the bootie to be elastic in the circumferential direction along its entire length. The bootie is elastic along a substantial part of its length. In particular, the bootie may be elastic in the circumferential direction in the midfoot portion. It is, however, also possible that the bootie is elastic in the circumferential direction along its entire length.

The bootie is arranged underneath and towards the inside of the outer construction of the upper assembly. The term outer construction generally refers to that part of the shoe that is seen from the outside of the shoe on top of the sole. It also includes the non-visible extensions of these materials, e.g. a lasted upper material. The outer construction further includes additional structures above and to the sides of the foot, even if they are not visible from the outside, e.g. a hidden tongue.

The bootie is not attached to the outer construction on the upper side of the mid-foot portion of the bootie. In other words, the bootie is free of attachments/attachment points with respect to the outer construction on the upper side of the midfoot portion. In yet other words, the bootie is free to move with respect to the outer construction on its upper side in the midfoot portion. In particular, it is possible that the bootie is not attached to the midfoot portion of the outer construction of the upper assembly.

The laminate is waterproof and breathable. Being made with the waterproof, breathable laminate, the bootie is also waterproof and breathable. In case the bootie has a seam connecting the edges of the functional layer to yield the sock-like shape, the seam region is made waterproof. For example, a waterproof seam tape may be arranged along the seam region. With the bootie being waterproof and breathable, the footwear as a whole may also be referred to as a waterproof, breathable footwear. The bootie forms a waterproof bag around the wearer's foot, lending waterproofness to the footwear as a whole. The footwear is breathable, because the outer construction has a breathable outer material and/or the sole is breathable. The sole may be made from a breathable material and/or may have a breathable structure, as will be explained below.

The terms upper assembly and sole generally indicate structures that are manufactured separately or subsequently in accordance with traditional shoe manufacturing, as described herein. However, with advances in shoe manufacturing, it is also possible that the upper assembly and the sole are formed as an integrated structure. For example, the combination of the upper assembly and the sole may be manufactured as a 3D knit or in accordance with another 3D manufacturing process. Such integrated structures comprising both the upper assembly and the sole are also encompassed by the footwear as claimed herein. It is also possible that the upper assembly comprises an integrated structure around the wearer's foot, which has the breathable outer material and the insole made as one integrated structure and into which the bootie is inserted.

According to a further embodiment, an air gap is present between the bootie and the outer construction on the upper side of the midfoot portion of the bootie. The air gap is present when no foot is inserted into the footwear. It is further possible that the air gap is also still present when a foot is inserted into the footwear. The air gap between the bootie and the outer construction allows for an expansion of the bootie on the upper side of the midfoot portion without any resistance by another material. In this way, the upper side of the midfoot portion of the bootie is particularly free to move, thus providing a lot of comfort and perceived freedom to move to the wearer.

According to a further embodiment, a compressible material layer is present between the bootie and the outer construction on the upper side of the midfoot portion of the bootie. A compressible material may also provide for freedom to move, while at the same time providing a somewhat stronger frame of stability for the foot than an air gap. It is also possible to have both a compressible material and an air gap present between the bootie and the outer construction on the upper side of the midfoot portion of the bootie. The compressible material may be either attached to the upper side of the bootie or to the outer construction. However, the compressible material may not be attached to both the outer construction and the bootie, in order for the relative movement of the bootie with respect to the outer construction to not be compromised.

According to a further embodiment, the bootie and the outer construction are jointly extendable on the upper side of the midfoot portion of the bootie. As discussed above, the circumferential elasticity of the bootie allows for an expansion thereof upon the insertion of the wearer's foot. With the bootie and the outer construction being jointly extendable, the two structures may jointly provide support for the wearer's foot. The potential for relative movement of the two structures with respect to each other is ensured due to the non-attachment on the upper side of the midfoot portion.

According to a further embodiment, the midfoot portion extends along at least 80%, in particular along at least 90%, further in particular along 100%, of the length from a foot instep portion of the upper assembly corresponding to a navicular area of a foot forward to a ball portion of the upper assembly corresponding to metatarsal point 1—phalanges joint of the foot. In other words, the upper side of the bootie is not attached to the outer construction—at least on the upper side of the bootie—along at least 80%, in particular along at least 90%, further in particular along 100%, of the length from a foot instep portion of the upper assembly corresponding to a navicular area of a foot forward to a ball portion of the upper assembly corresponding to metatarsal point 1—phalanges joint of the foot. The navicular area of the foot and the metatarsal point 1—phalanges joint of the foot are well-defined anatomical portions of the human foot. They are in particular well-defined for a given foot size, which allows for a derivation of the corresponding foot instep portion and the corresponding ball portion of the upper assembly for a given shoe size. It has been found that a high-level of perceived freedom to move and a high level of comfort can be achieved by allowing for relative movement of the bootie with respect to the outer construction in a very large part or the entire portion of the upper side of the foot between the navicular area and the metatarsal point 1—phalanges joint.

According to a further embodiment, the midfoot portion extends along at least 80%, in particular at least along at least 90%, further in particular along 100%, of the length from an upper tongue portion of the outer construction forward to a toe box area of the outer construction. In other words, the bootie is not attached to the outer construction—at least on the upper side of the bootie—along at least 80%, in particular along at least 90%, further in particular along 100%, of the length from an upper tongue portion of the outer construction forward to a toe box area. In this way, the attachment-free portion of the upper side of the bootie may be maximized in terms of the underlying shoe construction. In particular, the area between the upper tongue portion, where an attachment of the bootie to a collar region of the outer construction may be present, to the toe box area, where a further attachment between the bootie and the remaining shoe construction takes place, can be kept free of attachment points, thus maximising the freedom to move on the upper side of the bootie in the midfoot portion for the given shoe construction. In footwear technology, the toe box area is a well-defined portion of the shoe, where the toe portion of the foot is embedded into the particular footwear construction.

According to a further embodiment, the bootie is not attached to the outer construction around at least 50%, in particular around at least 60%, further in particular around at least 65%, of the circumference of the bootie in the midfoot portion. In other words, at least 50%, in particular at least 60%, further in particular at least 65%, of the circumference of the bootie are not attached to the outer construction. In yet other words, at least 50%, in particular at least 60%, further in particular at least 65%, of the circumference of the bootie are free to move within the footwear, with the free portion of the circumference forming an upper part of the bootie. The given values relate to all cross-sections along the midfoot portion of the bootie. In this way, a large un-attached area of the bootie is provided in the midfoot portion, such that the freedom to move is felt particularly well by the wearer. In particular, the upper side of the midfoot portion of the bootie, i.e. the un-attached part of the midfoot portion of the bootie, may have an extension of between 50% and 90%, in particular of between 60% and 85%, further in particular of between 65% and 85%, of a midfoot circumference of the bootie. Accordingly, a small portion, in particular between 10% and 15%, of the midfoot circumference of the bootie may be used for attachments. This small portion of attachment is provided on the lower side of the midfoot portion of the bootie, i.e. towards the sole or insole. It is stressed that the bootie may also be non-attached around its entire circumference in the midfoot portion.

According to a further embodiment, the one-piece functional layer is seamless on the upper side of the midfoot portion of the bootie. A one-piece functional layer may be entirely seamless, as has been described above will be described further below, or may be made from one single piece of functional layer/laminate, which is brought into a bootie form by sewing/glueing its edges together. In both cases, the bootie is considered a one-piece bootie, irrespective of the number of textile pieces used for forming a textile layer, as has been described above. In the former case, the bootie is considered seamless. In the latter case, the bootie is considered to have a seam. This seam may be arranged in such a way that the upper side of the midfoot portion of the bootie is free of said seam, i.e. seamless. In a simplified illustrative example, a one-piece bootie with one seam can be visualized as a particular cut of a laminate, wrapped around a last and sewn together at its edges. The cut of the laminate has such a shape that it fully covers the last. While the resulting seam may have various partial seams for adapting the laminate to the complex shape of a human foot, it is still considered a single seam holding the edges of the one-piece functional layer/laminate together. The waterproof nature of the bootie may be ensured by using a waterproof seam tape along said described seam. The feature of the one-piece functional layer being seamless on the upper side of the midfoot portion of the bootie means that said described seam, if present, does not extend in the region of the upper side of the midfoot portion of the bootie. Rather, the bootie is arranged such that the seam, if present, extends along the lower side of the bootie in the midfoot portion. In a particular embodiment, the one-piece functional layer is seamless on the whole upper side of the bootie. Further, it is explicitly pointed out that, with the one-piece functional layer being seamless on the upper side of the midfoot portion of the bootie, the whole bootie, including all its layers, may be seamless on the upper side of the midfoot portion of the bootie. With no seams being present on the upper side of the midfoot portion of the bootie, the upper portion of the foot does not rub against any seams, adding to the perceived comfort for the user.

According to a further embodiment, the one-piece functional layer is a seamless, one-piece functional layer. As described above, with the functional layer being a seamless, one-piece functional layer, the bootie is also considered a seamless, one-piece bootie, irrespective of the number of textile pieces used for making the waterproof, breathable laminate. In particular, the functional layer may be inherently shaped in the form of a bootie, e.g. by expanding the same over a last and a textile layer, thus having no seams. In other words, the functional layer/laminate may be manufactured to have the shape of a bootie, i.e. to have a sock-like shape, without the need for attaching different parts of the functional layer/laminate to each other. In particular, there is no need for sewing or glueing edges of the functional layer/laminate together in this case. Such bootie-shaped waterproof and breathable functional layer constructions are per se known, e.g. from WO 2015/123482 A1, the contents of which is incorporated herein in its entirety. In particular, it is known how the functional layer can be transformed from a plane layer into a bootie-shaped structure. For the details of said manufacturing process, reference is made to WO 2015/123482 A1. The provision of the seamless one-piece functional layer, and thus of the seamless, one-piece bootie, provides for a particularly high level of comfort to the wearer, because no seams interfere with the all-around feeling of stability, conformity and freedom to move.

According to a further embodiment, the upper assembly comprises an assembly insole and the bootie is attached to at least one of the outer construction and the assembly insole in the toe area and to at least one of the outer construction and the assembly insole in the heel area. The assembly insole is arranged below the bootie. The outer construction may be attached to the assembly insole in an outer circumferential portion of the assembly insole, e.g. an upper material of the outer construction may be lasted onto the assembly insole. The assembly insole may be breathable for water vapor to be discharged through the assembly insole and on to the sole of the footwear. However, it is also possible that the assembly insole is not made from a breathable material. In both the toe area and the heel area of the footwear, the bootie may be attached to one of the outer construction and the assembly insole or to both the outer construction and the assembly insole.

According to a further embodiment, the bootie is not attached to the assembly insole on a lower side of the midfoot portion of the bootie. In this way, the bootie is entirely un-attached in its midfoot portion. In this way, the freedom to move with respect to the surrounding shoe construction is maximized for the wearer's foot in the midfoot portion. The feeling of stability, provided by the elastic bootie, is paired with a maximum flexibility for the midfoot portion of the foot.

It is pointed out that it is also possible that the bootie is attached to the assembly insole on the lower side of the midfoot portion of the bootie. In particular, the bootie may be attached to the assembly insole around at most 50%, in particular around at most 40%, further in particular around at most 30%, further in particular around at most 20%, further in particular around at most 10%, of the midfoot circumference of the bootie. With the given values, a desired compromise between stability and flexibility can be achieved, while allowing for a well-defined positional arrangement of the bootie within the footwear by providing some form of attachment in the midfoot portion. Again, the given values relate to all cross-sections of the midfoot portion of the bootie.

According to a further embodiment, the bootie forms an outermost lower part of the upper assembly towards the sole of the footwear and the bootie is attached to at least one of the outer construction of the upper assembly and the sole in the toe area and to at least one of the outer construction of the upper assembly and the sole in the heel area. The bootie forming the outermost lower part of the upper assembly means that no separate assembly insole is provided underneath the bootie. In particular, the lower portion of the bootie may assume the function of an assembly insole, providing stability of the upper assembly during production and providing a well-defined lower part of the upper assembly for attachment to the sole. In this case, the sole may be directly attached to the bootie. It is pointed out that, both in the toe area and the heel area, the bootie may be attached to one of the outer construction and the sole or to both of these structures.

According to a further embodiment, the bootie is not attached to the sole on a lower side of the midfoot portion of the bootie. In this way, maximum freedom to move and flexibility is provided for the bootie in the midfoot portion of the footwear. It is pointed out that the bootie may also be attached to the lower side of the midfoot portion of the bootie. In particular, the sole may be attached to the lower side of the bootie along the same portions of the bootie circumference as described above with respect to the assembly insole. In the particular case of an injected sole, the sole may be directly injected on and formed onto the bootie and the outer construction of the upper assembly. In that process, the sole may form a strong attachment to the bootie, while the attachment area can be closely controlled in the manufacturing process and can be kept small for a large degree of freedom to move for the bootie.

According to a further embodiment, the bootie is attached to the outer construction of the upper assembly in a collar region of the footwear. In particular, the bootie may be attached to the outer construction around a shoe instep portion, i.e. around the opening through which the wearer inserts his/her foot. In this way, a third attachment region besides the toe region and the heel region is provided, such that the bootie is strongly fixed in position with respect to the remainer of the footwear, while maintaining freedom to move in the midfoot portion, as is highly desirable for user comfort, as discussed above.

According to a further embodiment, the bootie has a midfoot circumference in the midfoot portion that is between 60% and 99%, in particular between 70% and 95%, further in particular between 80% and 90% of a foot circumference in the midfoot portion. In this way, the bootie expands upon foot insertion and provides a pleasant feel of stability and comfort due to its elasticity, i.e. due to its pressure exertion on the foot. With the given midfoot circumference values of the bootie, a particularly pleasant compromise between the comfortable and stable fit of slight back pressure and sufficient freedom to move without feeling constrained by the back pressure can be achieved. The foot circumference is the circumference of a typical foot for the given shoe size. The typical foot is a non-deformed foot, i.e. a foot without abnormal deformations. The foot circumference may thus be defined in accordance with the anatomical properties of a foot, i.e. in accordance with the properties as given in medicine text book. It is also possible to define the foot circumference as a mean or medium value for a relevant set of measured feet circumferences.

According to a further embodiment, the bootie has elasticity in a longitudinal direction of the bootie. In this way, the bootie has elasticity both in the circumferential direction of the bootie and the longitudinal direction of the bootie, thus providing the feeling of stability and comfort to the wearer in an enhanced manner. When having longitudinal elasticity in addition to circumferential elasticity, the bootie is also said to have biaxial elasticity.

According to a further embodiment, the bootie has a longitudinal elasticity of at most 15 N/cm, in particular of at most 5 N/cm, at 10% elongation in the longitudinal direction of the bootie. The elasticity is measured as the force that is required to keep the sample at 10% elongation, with the cm value referring to the width of the test sample of the bootie. The elasticity is measured in accordance with DIN EN 14704-1, in the version of July 2005. The given values have been found to provide a bootie with a particularly comfortable fit, applying some force onto the foot for a stable and comfortable fit, while avoiding a constrained feeling of the foot due to too much pressure. In a particular embodiment, the bootie has a longitudinal elasticity of at least 0.5 N/cm at 10% elongation in the longitudinal direction of the bootie. In this way, a minimum amount of pressure for stability and a conformable fit may be achieved. The elasticity of the bootie may for example be regulated by using textiles for the at least one textile layer that have the desired retractive force.

According to a further embodiment, the bootie has a circumferential elasticity of at most 15 N/cm, in particular of at most 5 N/cm, at 30% elongation in the circumferential direction of the bootie. The elongation in the circumferential direction is defined in terms of a bootie sample, e.g. of the bootie material when the bootie is cut open. In other words, the elongation value is not defined for the bootie, as inserted into the footwear described herein, because an extension thereof in the circumferential direction would require stretching two layers of the bootie at the same time. The given elasticity values have been found to provide a very comfortable compromise between circumferential pressure on the foot, conveying stability and a comfortable fit, while keeping the elastic pressure at values that are not perceived as disturbing. In particular, the bootie may have a circumferential elasticity of at least 0.5 N/cm at 30% elongation in the circumferential direction of the bootie. In this way, a comfortable minimum back pressure onto the wearer's foot may be achieved. The elasticity of the bootie may for example be regulated by using textiles for the at least one textile layer that have the desired retractive force.

According to a further embodiment, the bootie has an elastic recovery of at least 75% in at least one of the longitudinal direction of the bootie and the circumferential direction of the bootie. In particular, the bootie has an elastic recovery of at least 75% in both the longitudinal direction and the circumferential direction of the bootie. The elastic recovery may again be measured according to DIN EN 14704-1, in the version of July 2005. With such elastic recovery, the comfortable fit of the bootie and, thus, of the footwear may be upheld over an extended period of time. The bootie may return nearly or entirely to its original shape after use, such that the wearer experiences the same or nearly the same comfortable fit, when using the footwear the next time.

According to a further embodiment, the one-piece functional layer comprises at least one of ePTFE (expended polytetrafluoroethylene), PU (polyurethane), PP (polypropylene), PES (polyester) and high density PE (high density polyethylene). All of the given materials are suitable for forming a waterproof and breathable functional layer and for achieving the elasticity described herein before. In a particular embodiment, the functional layer is an ePTFE membrane. It is also possible that the waterproof, breathable laminate has layers of different ones of the mentioned materials. For example, the waterproof, breathable laminate may have an ePTFE layer as well as a PU layer, with the PU layer keeping water from the ePTFE layer and thus ensuring that the breathability of the ePTFE layer is not compromised by water.

According to a further embodiment, the at least one textile layer is one of knitted, woven or non-woven textile. In particular, each of the at least one textile layer may be one of knitted, woven or non-woven textile. Knitted, woven or non-woven textiles are particularly suitable for the bootie of the footwear described herein, because these materials may be manufactured in a particularly beneficial elastic/stretchable manner. In this way, they are able to effectively contribute to the elasticity of the bootie. In these and other kinds of textiles that may be used, the fibers may be elastic, such as those made from polyamide, e.g. nylon, or polyurethane, e.g. elastance or spandex, sold inter alia under the trade mark Lycra, or rubber. It is not required that all fibers are elastic to make the textile stretchable. It is possible to use yarns made of different fibers, e.g. 20% polyurethane and 80% polyamide. Stretchable textiles may also be provided by providing suitable fiber structures, e.g. in a knit, or by texturing, e.g. crimping, the fibers in the textile.

According to a further embodiment, the outer construction comprises a breathable outer material. In a particular embodiment, the outer construction may essentially consist of a breathable outer material. In this way, the bootie and the breathable outer material may provide for a water vapor discharge path to the outside environment with a very low number of layers. In this way, the water vapor discharge may be achieved in a particularly efficient manner.

According to a further embodiment, the sole has water vapor discharge holes towards a lateral side of the sole and/or towards the bottom surface of the sole, with water vapor from the foot being discharged through the bootie through a sole interior and through the water vapor discharge holes to an outside environment of the footwear. In this way, water vapor discharge may be achieved though the sole, providing a short and effective water vapor discharge path from the underside of the foot to the outside environment of the footwear. The sole as a whole can thus be seen as a breathable sole, irrespective of whether or not the sole is manufactured from breathable material. The water vapor discharge through the sole may be in addition to the water vapor discharge through the outer construction of the upper assembly, in particular in addition to the water vapor discharge through a breathable outer material of the upper assembly.

Exemplary embodiments of the invention further include a bootie for use in footwear, as described in any of the embodiments above, wherein the bootie is made with a waterproof, breathable laminate, the waterproof, breathable laminate comprising a one-piece functional layer and at least one textile layer, and wherein the bootie has elasticity in circumferential direction of the bootie. The modifications, additional features, and effects, described above with respect to the footwear, apply to the bootie for use in said footwear in analogous manner.

Exemplary embodiments of the invention further include a method for producing footwear comprising an upper assembly having an outer construction and a sole, the method comprising the steps of providing a bootie made with a waterproof, breathable laminate, the waterproof, breathable laminate comprising a one-piece functional layer and at least one textile layer, wherein the bootie has elasticity in a circumferential direction of the bootie; and arranging the bootie in an inner space of the upper assembly and the sole, with the bootie being fixed in position in a toe region of the footwear and fixed in position in a heel region of the footwear and with the bootie not being attached to the outer construction on an upper side a midfoot portion of the bootie. The modifications, additional features and effects, described above with respect to the footwear, apply to the method for producing footwear in an analogous manner. The term inner space of the upper assembly and the sole indicates the space of the footwear that is intended for receiving the foot. It is denoted the inner space of the upper assembly and the sole, because both the upper assembly and the sole are arranged around this space. It is, however, possible that the upper assembly encases this whole space, with the sole being separated from this space by a portion of the upper assembly, such as an assembly insole. Such a construction is encompassed by the term inner space of the upper assembly and the sole. The term arranging the bootie in the inner space of the upper assembly and the sole encompasses both an insertion of the bootie into said inner space and a creation of the outer structure of the footwear around the bootie.

According to a further embodiment, the one-piece functional layer is a seamless, one-piece functional layer, with the step of providing the bootie comprising the step of expanding the seamless, one-piece functional layer over a last.

Further exemplary embodiments of the invention are described with respect to the accompanying figures, wherein:

FIG. 1 shows footwear in accordance with an exemplary embodiment of the invention, depicted in a longitudinal sectional view;

FIG. 2 shows the footwear of FIG. 1, depicted in a transverse sectional view;

FIG. 3 shows footwear in accordance with another exemplary embodiment of the invention, depicted in a longitudinal sectional view;

FIG. 4 shows the footwear of FIG. 3, depicted in a transverse sectional view;

FIG. 5 shows the anatomy of human feet in a top view;

FIG. 6 shows footwear in accordance with a further exemplary embodiment of the invention, depicted in a longitudinal sectional view;

FIG. 7 shows footwear in accordance with yet another exemplary embodiment of the invention, depicted in a longitudinal sectional view;

FIG. 8 shows exemplary embodiments of waterproof, breathable laminates, to be used in footwear in accordance with exemplary embodiments of the invention, in cross-sectional views.

FIG. 1 shows footwear 2 in accordance with an exemplary embodiment of the invention, depicted in a longitudinal sectional view, with the cross-sectional plane of FIG. 1 running substantially through the center of the footwear 2. In the exemplary embodiment of FIG. 1, the footwear 2 is a boot, also referred to as a boot-type shoe, whose upper assembly extends upwards over the wearer's ankle. The depicted boot-type shoe is exemplary in nature, and other types of footwear/shoes, in particular low shoes, may be constructed in an analogous manner.

The shoe 2 comprises an upper assembly 4 and a sole 6. The shoe is of a lasted construction. The upper assembly 4 comprises a breathable outer material 40, such as leather, suede, textile or any other suitable material, and an assembly insole 44. The breathable outer material 40 is perimetrically lasted onto the assembly insole 44 from the bottom. In particular, the breathable outer material 40 is glued onto the bottom of the assembly insole 44 around its perimeter with a lasting glue.

The upper assembly 4 further comprises a tongue 42. In the exemplary embodiment of FIG. 1, the tongue 42 is an originally separate structure from the breathable outer material 40 and is attached thereto, e.g. via sewing or gluing. It is also possible that the tongue 42 and the breathable outer material 44 are integrally formed from a continuous piece of material. The breathable outer material 40 and the tongue 42 form an outer construction of the footwear 2. In general, the outer construction of the footwear 2 may be a single integrated structure, such as a three-dimensional knit, or may be assembled from various originally separate pieces of a breathable material, as is for example common in leather shoes/boots.

In the exemplary embodiment of FIG. 1, the sole 6 is a solid structure of a non-breathable material, e.g. a solid plastic structure. In the exemplary embodiment of FIG. 1, the sole 6 is injected onto the lower side of the upper assembly 4, forming a strong bond to the lasted portion of the outer material 40 and to the assembly insole 44 in the process of injection. The sole 6 may also be glued to the lower portion of the upper assembly 4. It is further possible that the sole 6 is made from inherently breathable materials, such as leather, and/or that the sole has a structure that allows for breathability through the sole, as will be described below.

The upper assembly 4 further includes a bootie 50. The bootie 50 is a sock-like structure that is inserted into the space between the outer construction of the upper assembly, comprising the breathable outer material 40 and the tongue 42, and the assembly insole 44. Being arranged in the interior space of the upper assembly 4, the bootie 50 may also be referred to as a shoe insert. In the exemplary embodiment of FIG. 1, the upper end of the bootie 50 is at the same height as the upper end of the outer material 40. It is also possible that the upper end of the bootie 50 ends below the upper end of the outer material 40 or extends above the upper end of the outer material 40.

The bootie 50 is made with a waterproof, breathable laminate. In particular, the exemplary bootie 50 of FIG. 1 is a waterproof, breathable laminate, shaped into the sock-like form. The waterproof, breathable laminate comprises a one-piece, seamless functional layer, which is manufactured by stretching the functional layer over a shoe last. In addition, the waterproof, breathable laminate comprises two textile layers arranged on opposite sides of the functional layer and adhered to the functional layer. Accordingly, the bootie 50 is made with a three-layered waterproof, breathable laminate.

The footwear 2 has a forefoot portion 90, a midfoot portion 92, and a rearfoot portion 94. The forefoot portion 90, the midfoot portion 92, and the rearfoot portion 94 are separated by dashed lines in FIG. 1. The forefoot portion 90 may also be referred to as a toe region of the footwear. The rearfoot portion 94 comprises a heel region 96 and collar region 98. Given the fairly low construction of the boot 2 of FIG. 1, the rearfoot portion 94 consists of the heel region 96 and the collar region 98 in the exemplary embodiment of FIG. 1. However, it is also possible that further regions are interposed between the heel region 96 and the collar region 98 in other constructions.

The bootie 50 is attached to the breathable outer material 40, to the tongue 42, and to the assembly insole 44 in the forefoot portion/toe region 90, in the heel region 96, and the collar region 98. In particular, the bootie 50 is fixed in position by various glue portions, as will be described below. The bootie 50 is attached to the breathable outer material 40 and the tongue 42 in the collar region 98 via a first glue portion 70, which surrounds the circumference of the bootie 50. The bootie 50 is attached to the outer material 40 in the heel region 96 via a second glue portion 72. The second glue portion 72 extends around a part of the circumference of the bootie 50, e.g. in a substantially semi-circular manner. The bootie 50 is attached to the assembly insole 44 in the heel region 96 via a third glue portion 74. The third glue portion 74 has an extension corresponding substantially to the stance area of the heel of the wearer's foot. The bootie 50 is further attached to the assembly insole 44 in the forefoot portion/toe region 90 via a forth glue portion 76. Further, the bootie 50 is attached to the breathable outer material 40 in the forefoot portion/toe region 90 via a fifth glue portion 78. The forth glue portion 76 and the fifth glue portion 78 extend substantially across the entire width of the upper assembly 4 in the forefoot portion 90. It is understood that the arrangement of the glue portions is exemplary in nature and that the positional fixation of the bootie in the toe region, the heel region, and the collar region may be achieved via other glue arrangements as well.

The bootie 50 is free of attachments to the remainder of the upper assembly 4 in the midfoot portion 92. In particular, in the exemplary embodiment of FIG. 1, the bootie 50 is neither attached to the outer construction, comprising the breathable outer material 40 and the tongue 42, nor to the assembly insole 44 in the midfoot portion 92. In this way, the bootie 50 is free to move with respect to the surrounding elements of the upper assembly in the midfoot portion 92. A complete freedom of relative motion is established in the midfoot portion, which provides a comfortable fit to the user. In particular, the bootie 50 is not attached to the remainder of the upper assembly 4 in the midfoot portion corresponding to the region between an upper tongue portion and the beginning of the toe box area of the upper assembly 4.

In the midfoot portion 92, the bootie has a smaller circumference than the wearer's foot. This is illustrated in FIG. 1 as follows. The outer construction of the upper assembly 4, comprising the breathable outer material 40 and the tongue 42, is depicted to roughly correspond to the shape and size of the wearer's foot.

As can be seen in FIG. 1, an air gap 52 is present above an upper side of the bootie 50 in the midfoot portion 92. This air gap 52 illustrates that the circumference of the bootie 50 is smaller than the circumference of the wearer's foot, which roughly corresponds to the extension of the outer construction.

The bootie 50 is elastic in a circumferential direction, at least in the midfoot portion 92. In this way, the bootie 50 is able to expand upon the insertion of the wearer's foot. This elastic expansion of the bootie 50 pushes the upper side of the bootie towards the breathable outer material 40 and the tongue 42 in the mid-foot portion 92, thus shrinking or eliminating the air gap 52 when the wearer's foot is inserted. The air may escape through the breathable outer material 40 or through the tongue 42. When expanding, the bootie exerts a force onto the wearer's foot due to its elasticity. In this way, the wearer experiences a stable and comfortable fit in the midfoot portion 92, while the potential for relative motion with respect to the surrounding part of the upper assembly 4 ensures freedom to move and increases the experienced comfort level to the wearer.

In a particular example of a footwear of shoe size 43, the bootie may have a circumference of between 200 mm and 225 mm in all cross-sections along the mid-foot portion. This bootie may have a circumferential elasticity of about 5 N/cm at 30% elongation in the midfoot portion. The bootie may or may not have longitudinal elasticity in the midfoot portion. For example, the bootie may have a longitudinal elasticity of about 5 N/cm at 10% elongation in the midfoot portion.

FIG. 2 shows the footwear 2 of FIG. 1 in a transverse sectional view. In particular, FIG. 2 shows the footwear 2 of FIG. 1 along the cross-sectional plane indicated by A-A in FIG. 1. The cross-sectional plane of FIG. 2 cuts through the midfoot portion 92 roughly in the middle thereof.

As described above, the bootie 50 is completely un-attached in the midfoot portion 92. This is further illustrate in FIG. 2, where no glue portions or other attachment means are shown between the bootie 50 and the surrounding shoe structure, namely the assembly insole 44, the breathable outer material 40 and the tongue 42. Also, the air gap 52 is again illustrated in FIG. 2. In particular, the air gap 52 is depicted to have about 20% of the height of the space between the assembly insole 44 and the tongue 42 in the center of the shoe. While it is pointed out that the FIGS. are not to scale, but aim at conveying illustrative examples, the air gap 52 may have a height of between 1% and 20% of the distance between the assembly insole 44 and the tongue 42. As described above, in addition to/as an alternative to the air gap 52, a compressible material may be provided between the bootie 50 and the breathable outer material 40/tongue 42.

FIG. 3 shows footwear 2 in accordance with another exemplary embodiment of the invention. The footwear 2 of FIG. 3 has similarities with the footwear 2 of FIGS. 1 and 2. For those features/elements that are not described with respect to FIG. 3, reference is made to the description of the footwear of FIGS. 1 and 2 above.

The footwear 2 of FIG. 3 also has an upper assembly 4 and a sole 6. The construction of the upper assembly 4 of FIG. 3 differs from the upper assembly 4 of FIG. 1 in that it does not have an assembly insole. In other words, the upper assembly 4 of FIG. 3 is free of an assembly insole, i.e. free of a dedicated structural element that is arranged underneath the wearer's foot and that forms the pivot during manufacture of the upper assembly. Rather, the lower portion of the bootie 50 assumes the function of the pivot during manufacture of the upper assembly. In other words, while not being a dedicated assembly insole, the lower portion of the bootie 50 of FIG. 3 has assembly insole functionality.

With the upper assembly 4 of FIG. 3 not having an assembly insole, the breathable outer material 40 is lasted onto the lower side of the bootie 50. In particular, the third glue portion 74, which is arranged in the heel region 96, provides for an attachment between the bootie 50 and the breathable outer material 40. Analogously, the fourth glue portion 76, which is arranged in the toe region 90, provides for an attachment between the bootie 50 and the breathable outer material 40. As compared to the footwear of FIG. 1, the third glue portion 74 has a shorter longitudinal extension along the bootie 50. The lasted portions of the breathable outer material 40 have a greater longitudinal extension in the FIG. 3 embodiment, as compared to FIG. 1.

Similar to the FIG. 1 embodiment, the sole 6 of the footwear 2 of FIG. 3 is also an injected sole. However, in the absence of an assembly insole, the sole 6 of FIG. 3 is injected onto the lasted portions of the breathable outer material 40 and directly onto the underside of the bootie 50. When being injected, in particular when being injection molded, the material of the sole 6 reaches the bootie 50 and forms an adhesive bond therewith. The material of the sole 6 also enters into the space between lasted portions of the breathable outer material 40 and the bootie 50 adjacent to the third and fourth glue portions 74, 76. Also, the material of the sole attaches to the underside of the lasted portions of the breathable outer material 40. In this way, the injected sole material provides for a strong adhesive bond between the sole 6, the breathable outer material 40 and the bootie 50. The bootie 50 is thus attached to the sole 6 along its entire underside in the midfoot portion 92. In particular, the bootie 50 is attached to the sole 6 along its entire underside between the third and fourth glue portions 74, 76. It is, however, pointed out that this is not necessarily the case for all longitudinal cross-sections through the footwear 2. It will be shown with respect to FIG. 4 that the attachment between the underside of the bootie 50 and the sole 6 is confined to a comparably narrow attachment region.

FIG. 4 shows the footwear 2 of FIG. 3 in a transverse sectional view. In particular, FIG. 4 shows the footwear 2 of FIG. 3 along the cross-sectional plane indicated by A-A in FIG. 3. The cross-sectional plane of FIG. 4 cuts through the midfoot portion 92 roughly in the middle thereof.

As described above, the sole 6 of the exemplary embodiment of FIGS. 3 and 4 is attached to the lasted portions of the breathable outer material 40 and to the underside of the bootie 50. In the midfoot cross-section depicted in FIG. 4, the sole is attached to the underside of the bootie 50 in a center portion thereof. The term center portion refers to a region around the center of the bootie a transverse direction. The attachment between the sole 6 and the underside of the bootie 50 may be the same or similar in all transverse cross-sections in the midfoot area. In this way, the attachment between the sole 6 and the bootie 50 is confined to a comparably small area. While providing some degree of stability for the overall footwear construction, the attachment area is kept small, leading to a highly flexible arrangement of the bootie 50 within the footwear 2 and to a high level of perceived freedom to move for the wearer.

It is pointed out that the attachment area between the sole 6 and the bootie 50 may be adapted according to the requirements of a particular application. It is for example also possible that the sole 6 is attached to the bootie 50 across the entire width between the lasted portions of the breathable outer material 40. The attachment area can be controlled well during manufacture. A protective layer may be arranged on the bootie in those portions that are not supposed to be reached by sole material. This protective layer may be pulled out from the underside of the bootie 50 along its side portions, after the sole 6 has been injected.

FIG. 5 depicts the anatomy of the bones of human feet in a top view. In particular, FIG. 5 depicts the bones of a right foot 100 and a left foot 102, including the extensions of the right and left feet around the bones, indicated by respective circumferential lines. The representation of the feet 100, 102 of FIG. 5 is a standard representation of human feet, as provided in a medicine textbook.

In both the right foot 100 and the left foot 102, the navicular bone is provided with reference numeral 104. The outline of the navicular bone can be referred to as the navicular area 104 of the foot. Further, in both the right foot 100 and the left foot 102, the metatarsal 1 bone is provided with reference numeral 108. The front of each metatarsal 1 bone 108 ends in the phalanges joint. This front end is indicated with reference numeral 106 and is referred to herein as metatarsal point 1—phalanges joint.

As described above, it has been found that relative freedom to move between a bootie and an outer construction on the upper side of the midfoot portion provides for a high level of comfort to the wearer of a shoe. It has further been found that providing this freedom to move along at least 80%, in particular along at least 90%, more in particular along 100%, of the length between the navicular area 104 and the metatarsal point 1—phalanges joint 106 provides for a particularly high level of comfort to the wearer. Measured from the front-most portion of the navicular area 104 to the front-most portion of the metatarsal point 1—phalanges joint 106, this length corresponds to about 40% of the length of the human foot.

FIG. 6 shows footwear 2 in accordance with another exemplary embodiment of the invention. The footwear 2 of FIG. 6 is a variation of the footwear 2 of FIGS. 1 and 2. In particular, while the upper assembly 4 of the footwear 2 of FIG. 6 is the same as the upper assembly 4 of FIGS. 1 and 2, the sole 6 of the footwear 2 of FIG. 6 is a variation of the sole 6 of FIGS. 1 and 2. FIG. 6 shows a cross-sectional view analogous to the cross-sectional view of FIG. 2.

The sole 6 of the footwear 2 of FIG. 6 is a breathable sole. In particular, the sole 6 is of a breathable structure. The sole 6 has a circumferential portion 60 and stabilizing bars 62. The stabilizing bars 62 and the circumferential portion 60 may be integrally molded from a plastics material. While the stabilizing bars 62 are depicted as longitudinal bars in the cross-sectional view of FIG. 6, the stabilizing bars 62 may be arranged in different directions. In particular, the stabilizing bars 62 may form a stabilization grid within the circumferential portion 60. The stabilizing bars 62/the stabilization grid may extend over one or more portions of the sole 6, e.g. over a forefoot portion of the sole 6 and/or over a heel portion of the sole 6.

In between the stabilizing bars 62/stabilizing grid, there are provided water vapor discharge holes 66. The water vapor discharge holes 66 are comparably large in diameter and thus allow for the discharge of large amounts of water vapor through the sole 6. The water vapor discharge holes 66 extend substantially vertically though the sole 6. Above the water vapor discharge holes 66, there is provided a barrier material 64. In particular, the barrier material is provided between the circumferential portion 60 of the sole 6, below the assembly insole 44, and above the stabilizing bars 62. The barrier material is breathable, i.e. water vapor permeable, and protects the upper assembly 4 thereabove from foreign objects that may penetrate through the water vapor discharge holes 66.

The footwear 2 of FIG. 6 allows for water vapor discharge through the breathable outer material 40 as well as through the sole 6. Water vapor can travel from the underside of the wearer's foot through the bootie 50, through the assembly insole 44, through the barrier material 64, and through the water vapor discharge holes 66 to an outside environment of the shoe. With the bootie being made with a breathable, waterproof laminate, the wearer's foot is protected from water, also from water entering through the water vapor discharge holes 66.

FIG. 7 shows footwear 2 in accordance with yet another exemplary embodiment of the invention. The footwear 2 of FIG. 7 is a variation of the footwear 2 of FIGS. 1 and 2. In particular, while the upper assembly 4 of the footwear 2 of FIG. 7 is the same as the upper assembly 4 of FIGS. 1 and 2, the sole 6 of the footwear 2 of FIG. 7 is a variation of the sole 6 of FIGS. 1 and 2. FIG. 7 shows a cross-sectional view analogous to the cross-sectional view of FIG. 2.

The sole 6 of the footwear 2 of FIG. 7 is a breathable sole, as is the sole 6 of the footwear 2 of FIG. 6. While the sole 6 of FIG. 6 relies on water vapor discharge towards the bottom of the sole, the sole 6 of FIG. 7 relies on water vapor discharge towards the lateral sides of the sole. The bottom surface of the sole 6 of FIG. 7 is free of water vapor discharge holes. However, it is also possible that the sole of footwear in accordance with exemplary embodiments of the invention has water vapor discharge holes towards the bottom and towards the side.

The sole 6 of FIG. 7 has a structure or material for allowing air flow through it, generally indicated with reference numeral 68. The structure or material 68 may be any suitable structure or material that allows for air flow theretrough and, thus, allows for the transport of water vapor, coming from the inside of the shoe, towards the lateral sides and out of the shoe. The structure or material 68 may for example be a channel structure or a spacer fabric or a granulate fill or any other suitable structure or material. The sole 6 further comprises a plurality of water vapor discharge holes 66. In the cross-sectional view of FIG. 7, two of the plurality of water vapor discharge holes 66 are shown. It is understood that a suitable number of water vapor discharge holes 66 may be arranged around the periphery of the sole 6.

The water vapor discharge holes 66 are provided from the structure or material 68 towards the lateral sides of the sole 6. In particular, the water vapor discharge holes 66 are substantially horizontal in the exemplary embodiment of FIG. 7. Further, the water vapor discharge holes 66 are substantially circular in cross-section in the exemplary embodiment of FIG. 7. However, the water vapor discharge holes may have any suitable cross-section.

The footwear 2 of FIG. 7 also allows for water vapor discharge through the breathable outer material 40 as well as through the sole 6. Water vapor can travel from the underside of the wearer's foot through the bootie 50, through the assembly insole 44, into and through the structure or material 68, and through the water vapor discharge holes 66 to an outside environment of the shoe. Due to the straight air flow path between the left and right sides of the sole 6, an efficient water vapor discharge through the sole 6 may be achieved. With the bootie being made with a breathable, waterproof laminate, the wearer's foot is protected from water, also from water entering through the water vapor discharge holes 66.

FIG. 8 shows exemplary embodiments of laminates that may be used for the bootie 50 for exemplary embodiments of the invention. FIG. 8A shows a waterproof, breathable three-layer laminate 51. The three-layer laminate 51 has a functional layer 54, which is an ePTFE membrane in the exemplary embodiment of FIG. 8A, a first textile layer 56, and a second textile layer 58. The first and second textile layers 56, 58 are knitted layers in the exemplary embodiment of FIG. 8A.

FIG. 8B shows a waterproof, breathable two-layer laminate 51. The two-layer laminate 51 has a functional layer 54, which is an ePTFE membrane in the exemplary embodiment of FIG. 8B, and a textile layer 56, which is a knitted layer in the exemplary embodiment of FIG. 8B. The laminate 51 can be used in any orientation for the bootie 50, i.e. the two-layer laminate 51 can be used with the functional layer 54 facing the wearer's foot and with the textile layer 56 facing the wearer's foot.

Test Methods and Definitions

A functional layer and a laminate are considered to have waterproof characteristics in case the requirements specified in DIN EN 343 (2010) are met, i.e. a test of the liquid water resistance with respect to hydrostatic water pressure according to EN 20 811 (1992) yields a liquid water resistance Wp of 8000 Pa, or more.

Water vapor permeability, as used herein concerning the functional layer and the laminate comprising the functional layer, is tested and defined in EN ISO 15496, also known as the “Cup Test”. A 20×20 cm or Ø100 mm sample of the waterproof, breathable laminate is placed onto a container containing water and covered with a membrane. Then a cup containing potassium acetate and being covered by the same membrane is placed on the sample. Water vapor passes through the laminate into the cup, whose weight increase is then determined. The laminate is considered water vapor permeable or breathable if the water vapor permeability is greater than or equal to 0.01 g/(Pa*m2*h). If the required size of the sample cannot be obtained, a smaller sample may be used for the measurement using a smaller cup containing half the amount of potassium acetate specified in the Norm, i.e. 50 g instead of 100 g and mixed with 15.6 g of water. The terms water vapor permeability and breathability are used interchangeably herein. Accordingly, the waterproof, breathable laminate may also be referred to as waterproof, water vapor permeable laminate.

The waterproofness of footwear may be determined by use of the Centrifuge test described in U.S. Pat. No. 5,329,807, and incorporated by reference herein in its entirety. The centrifuge tests may be carried out for 30 minutes. The footwear article is considered to be waterproof if no leakage is seen after 30 minutes.

The breathability of footwear may be assessed in accordance with the determination of the Whole Boot Moisture Vapor Transmission Rate Test in accordance with the Department of Defense Army Combat Boot Temperate Weather Specifications. The specifications are as follows:

Whole boot breathability

The boot breathability test shall be designed to indicate the Moisture Vapor Transmission Rate (MVTR) through the test sample by means of a difference in concentration of moisture vapor between the interior and the exterior environment.

Apparatus

a. The external test environment control system shall be capable of maintaining 23 (±1)° C. and 50%±2% relative humidity throughout the test duration.

b. The weight scale shall be capable of determining the weight of test samples filled with water to an accuracy of (±0.01) gram.

c. The water holding bag shall be flexible so that it can be inserted into the test sample and conform to the interior contours; it must be thin enough so that folds do not create air gaps; it must have much higher MVTR than the footwear product to be tested; and it must be waterproof so that only moisture vapor contacts the interior of the footwear product rather than liquid water.

d. The internal heater for the test sample shall be capable of controlling the temperature of the liquid water uniformly in the test sample to 35 (±1)° C.

e. The sealing method around the collar of the test sample shall be impervious to both liquid water and water vapor.

Procedure

a. Place sample in test environment and condition for at least 12 hours.

b. The heating device is inserted into the water holding bag and the complete assembly is then placed into the test sample opening and filled with water to a height of 5cm measured from inside sole.

c. Seal opening around the collar with plastic wrap around the top of the footwear and tape over using packaging tape.

d. Heat water in test sample to 35° C.

e. Weigh test sample and record as Wi.

f. Hold temperature in test sample after weighing for a minimum of 4 hours.

g. After a minimum of 4 hours, reweigh test sample. Record weight as Wf and test duration as Td.

h. Calculate MVTR of the test sample in grams/hour from the equation below:

MVTR=(Wi−Wf)/Td.

This test is in accordance with ASTM D8041 (2016).

For example, for a low ankle shoe of European shoe size 42, the footwear may be considered breathable if above calculated value is above 1.5 grams/hour. For larger/smaller shoe sizes, said limit value may be extrapolated in accordance with the increased/decreased surface area of the shoe.

The waterproofness and the breathability of the bootie as a whole may also be determined by use of the Centrifuge test and the Whole Boot Moisture Vapor Transmission Rate Test, respectively, as laid out above.

The elasticity of the laminate and of the bootie may be measured according to DIN EN 14704-1 (July 2005), method A. The test may be carried out as set out therein, while using test samples of the following configuration: Test sample width=25 mm, test sample testing length=50 mm (testing length referred in DIN EN as gauge length, the length of the sample between the tensile machine clamps), whole length of test sample=100-150 mm. The test sample is subject to 3 to 5 consecutive test cycles. In each test cycle, the test sample is subject to a constant extension of 30% of said gauge length, in samples cut circumferentially and 10% of said gauge length in samples cut longitudinally to the formed bootie, and the maximum force of the last cycle is measured. The extension and retraction rate of the sample should be set to 250 mm/min. The specimen length is measured after final cycle finishes by laying it on a flat surface and measuring the length between applied reference markers within the gauge length with a calibrated ruler. The elastic recovery expressed in % is calculated through subtracting the final length between applied reference markers from the original length between said reference markers, dividing then by the original length between said reference markers, and finally multiplying the result by 100. Otherwise, test conditions are as set out in DIN EN 14704-1 (July 2015), method A. Elasticity is defined as a property of material in which the material extends at the application of a force or extension and recovers towards its original length after removing the applied force or extension. The elasticity of the specimen is therefore determined via measuring the force recorded during applied extension (or vice versa) and the ability of the material to recover towards its original length after said applied force or extension has been removed.

While the invention has been described with reference to exemplary embodiments, 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 invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

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