Patent Publication Number: US-7716851-B2

Title: Waterproof and breathable sole for shoes

Description:
CROSS REFERENCE 
   This application is a continuation of and is based upon and claims the benefit of priority under 35 U.S.C. §120 for U.S. Ser. No. 10/529,187, filed Mar. 24, 2005, which is a National Stage of PCT/EP03/10395, filed Sep. 18, 2003, and claims the benefit of priority under 35 U.S.C. §119 from Italian Patent Application No. PD2002A000246, filed Sep. 24, 2002, the entire contents of each which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an improved waterproof and breathable sole for shoes and to the shoe manufactured with such sole. 
   2. Description of the Related Art 
   Waterproof and breathable soles made of plastics for shoes are already known. 
   One of such soles is disclosed in WO 97/14326. 
   In this case, the sole comprises:
         a mid-sole with a membrane made of a material that is impermeable to water and permeable to water vapor, associated with a lower protective layer of a material that is resistant to hydrolysis, water-repellent, breathable and/or perforated;   a tread made of perforated elastomer, which is joined perimetrically and hermetically to the mid-sole.       

   The waterproof and breathable sole disclosed in WO 98/51177 is also known; it comprises a preassembled insert in which there is a membrane that is impermeable to water and permeable to water vapor, associated with a lower protective layer made of a material that is resistant to hydrolysis, water-repellent, breathable and/or perforated. 
   The insert is completed by an element that is overmolded or over-assembled, surrounds the membrane and the protective layer, and is joined hermetically to them. 
   The insert is part of a mid-sole and is joined, together with said mid-sole, to a tread made of perforated plastic material, which is overmolded or over-assembled. 
   In both cases, the protective layer arranged below the membrane is designed to protect it against piercing due to foreign objects that have accidentally passed through the holes. 
   The protective layer is usually made of felt and is coupled to the membrane in a breathable manner (by means of spots of thermoplastic adhesive, for example of the polyurethane-based type) to allow the passage of the vapor from the inside of the shoe toward the outside through the holes provided in the tread. 
   Breathable and waterproof soles for shoes are also known from U.S. Ser. No. 09/978,634 and EPA No. 01124210.4 and comprise, at least along part of their extension, a lower waterproof component that constitutes the tread, an upper component with a supporting structure that is provided with holes connected to outlets at least on the upper and edge surfaces, and a waterproof vapor-permeable membrane that surrounds externally at least the outward-facing regions of the upper component. 
   The lower component, the upper component and the membrane are joined hermetically in the regions of possible internal water infiltration. 
   Although the above described soles have now been available commercially for years and are unanimously acknowledged as being capable of producing an exchange of heat and water vapor between the microclimate inside the shoe and the external microclimate, such soles, in some cases, such as for example use on the part of users with quantitatively higher-than-average foot perspiration, have been found to have a breathability that is insufficient to fully dispose of the generated vapor and ensure the correct microclimate inside the shoe. 
   The structure of the above described soles in fact has, at least in a downward region, layers of microperforated plastic material, i.e., provided with holes having a diameter on the order of 1-2 millimeters, and the total area of the microperforations in any case limits the area of the membrane that is actually affected by the exchange of heat and vapor. 
   SUMMARY OF THE INVENTION 
   The aim of the present invention is to provide a waterproof and breathable sole for shoes, and the corresponding shoe, having an improved structure that is capable of utilizing to the maximum extent the breathability of the membrane that is impermeable to water and permeable to water vapor. 
   Within this aim, an object of the invention is to provide a waterproof and breathable sole for shoes having a structure that allows to enlarge the area of the membrane until it affects substantially the entire sole of the foot. 
   Another object is to provide a sole that does not entail particular constructive complications with respect to conventional soles. 
   Another object is to provide a sole whose costs are competitive with respect to conventional types. 
   This aim and these and other objects that will become better apparent hereinafter are achieved by a waterproof and breathable sole for shoes having a structure that is characterized in that it comprises:
         a supporting layer which, at least in a preset macroportion, is made of net, felt or other diffusely perforated material;   a membrane that is made of a material that is impermeable to water and permeable to water vapor and is associated above said supporting layer at least in said at least one preset macroportion made of net, felt or other diffusely perforated material, which it covers;   a tread made of plastic material, with at least one through macroperforation at said at least one preset macroportion made of net, felt or other diffusely perforated material, said tread being joined hermetically to said membrane and to said supporting layer at least at the perimeter of said at least one macroportion made of net, felt or other diffusely perforated material.       

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the present invention will become better apparent from the detailed description of some embodiments thereof, illustrated by way of non-limitative example in the accompanying drawings, wherein: 
       FIG. 1  is a longitudinal sectional view of a waterproof and breathable sole for shoes having the structure according to the invention, in a first embodiment; 
       FIG. 2  is an enlarged-scale sectional view of a detail of the sole of  FIG. 1 ; 
       FIG. 3  is an enlarged-scale sectional view of a detail of a variation of the sole of  FIG. 1 ; 
       FIG. 4  is an exploded view of the components of the variation of  FIG. 3 ; 
       FIG. 5  is a sectional view, taken along a longitudinal plane, of a waterproof and breathable sole for shoes having the structure according to the invention in a constructive variation; 
       FIG. 6  is an exploded sectional view, taken along a longitudinal plane, of a waterproof and breathable sole for shoes having the structure according to the invention in a second embodiment thereof; 
       FIG. 7  is a sectional view, taken along a longitudinal plane, of the sole of  FIG. 6  in the assembled condition; 
       FIG. 8  is a bottom perspective view of a shoe provided with the sole of  FIGS. 6 and 7 ; 
       FIG. 9  is an enlarged-scale sectional view of a detail of  FIG. 7 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to  FIGS. 1 to 4 , a waterproof and breathable sole for shoes has, in a first embodiment, a structure that comprises a supporting layer  10  which is made of net, felt or other diffusely perforated material in preset macroportions  11 . 
   The supporting layer  10  constitutes, in this case, the assembly insole of the shoe. The term “macroportion” is used to reference portions of area preferably on the order of at least one square centimeter. 
   In the other portions  12 , the supporting layer  10  can be constituted by a fine mesh of synthetic material, leather or other commonly used materials. The structure also comprises a membrane  13 , which is made of a material that is impermeable to water and permeable to water vapor (which is commonly commercially available and is made for example of expanded polytetrafluoroethylene), laminated onto a fine mesh  14  for supporting it, which lies above it, is made of synthetic material, and is arranged above the supporting layer  10  at at least the macroportions  11 , which it covers. 
   The membrane  13  can be made of airtight material or of air-permeable material. 
   The membrane  13  can be coupled by means of spots of glue (not shown in the figures) to the supporting layer  10  in the regions of contact. 
   A tread  15  made of plastic material has through macroperforations  16  at the macroportions  11  and is joined hermetically to the membrane  13  and to the supporting layer  10  at least at the perimeters of the macroportions  11 . 
   The through macroperforations  16  can be crossed by cross-members  16   a , which prevent transverse deformations of the assembly by acting as tension members in the deformations that occur as a consequence of use. 
   The coupling ( FIGS. 1 and 2 ) can be provided for example by means of a perimetric layer  17  of adhesive, which is spread so as to penetrate, when the components are joined, through the meshes of the net and join monolithically the tread  15  and the membrane  13 . 
   As an alternative ( FIGS. 3 and 4 ), it is possible to arrange between the supporting layer  10  and the membrane  13 , or between the tread  15  and the supporting layer  10 , a film  18  made of PVC or PU and then perform a high-frequency welding between the tread  15  and the membrane  13  by melting the film  18 , with penetration thereof between the meshes of the net so as to join the components monolithically. 
   As a further alternative, it is possible to perform high-frequency welding of the layer  10  and the membrane  13  to the film  18  and then glue the assembly to the tread  15 . 
   An inner sole, not shown in the figures, made of breathable or diffusely perforated material, for supporting the foot, can be arranged above the supporting layer  10  and the membrane  13  with the fine mesh  14 . 
   The described sole can be applied, in the commonly known ways, to an upper  20  of any kind so as to constitute a shoe  21 . 
   With reference to  FIG. 5 , in a slightly different embodiment it is possible to provide a single macroportion  11  that affects the entire sole of the foot without portions  12 , regardless of the arrangement of the through macroperforations  16  of the tread  15 . 
   In this case, the membrane  13  and its support  14  also affect the entire sole of the foot. 
   The glue  17  or the film  18  are arranged perimetrically. 
   With reference now to  FIGS. 6 to 9 , a waterproof and breathable sole for shoes according to a second embodiment has a structure that comprises a supporting layer  110  that is completely made of net, felt or other diffusely perforated material, which accordingly constitutes a single large macroportion  111 . 
   The sole again comprises a membrane  113  made of a material that is impermeable to water and permeable to water vapor (commonly commercially available and made for example of expanded polytetrafluoroethylene), laminated together with a fine mesh  114  for supporting it which lies above it, is made of synthetic material and is arranged above the supporting layer  110 , which it covers completely. 
   The membrane  113  can be made of airtight material or air-permeable material. 
   The membrane  113  is preferably coupled by means of spots of glue to the supporting layer  110 . 
   It is possible to arrange a protective layer  110   a , made for example of felt, below the membrane  113 , for example if the supporting layer is made of net. 
   A tread  115  made of plastic material is assembled to the supporting layer  110  and is joined hermetically to the membrane  113  at least at the peripheral region of said membrane. 
   The coupling can be provided by directly injecting the tread  115  onto the supporting layer  110  in a mold, with at least perimetric penetration through the meshes of the net or of the felt that is appropriately reduced in thickness at its perimeter, is perforated perimetrically or bordered with net so as to reach the membrane  113 . 
   The tread  115  is provided so as to form macroperforations  116 , for example a single large through macroperforation  116  that affects substantially all the sole of the foot, except for the perimeter  115   a , which is interrupted by protrusions  115   b  that form, together with the perimeter  115   a , the surface for contact with the ground. 
   The coupling between the tread  115  and the supporting layer  110  can be obtained also in the manners described in the first embodiment, i.e., by gluing or high-frequency welding. 
   The sole can be coupled to an upper  120 , so as to provide a shoe  121  that is assembled on an assembly insole  124  and is optionally coupled in a downward region to a filler layer  122  made of an expanded material such as diffusely perforated EVA, coconut fibers, etcetera. 
   The layer  122 , when it is made of diffusely perforated EVA or the like (therefore inherently waterproof but rendered air-permeable), can be used as a means for the perimetric hermetic high-frequency welding from above of the membrane  113  to the upper  120 . 
   The subsequent gluing of the tread  115  need not necessarily be hermetic. 
   The coupling between the sole and the upper  120  is in the peripheral region of said assembly insole and is provided for example by gluing or high-frequency welding. 
   An inner sole  119  made of breathable or diffusely perforated material can be arranged above the assembly insole  124 . 
   The inner sole  119  can also be coupled in a downward region to a shock-absorbing layer  119   a  made of polyethylene or the like, which is diffusely perforated and anatomically contoured. 
   Other layers, not shown, such as cleaning insoles, absorbent layers et cetera, can be provided. 
   In practice it has been observed that the intended aim and objects of the present invention have been achieved. 
   A waterproof and breathable sole for shoes has in fact been provided whose structure is capable of utilizing to the fullest extent the breathability of the waterproof vapor-permeable membrane. 
   The structure allows to enlarge the area of the membrane until it affects substantially the entire sole of the foot. 
   The manufacture of the sole does not entail particular constructive complications with respect to conventional soles. 
   The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. 
   All the details may further be replaced with other technically equivalent elements. 
   In practice, the materials, so long as they are compatible with the contingent use, as well as the dimensions, may be any according to requirements. 
   Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.