Note: Descriptions are shown in the official language in which they were submitted.
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VAPOR-PERMEABLE SHOE WITH WATERPROOF AND VAPOR-
PERMEABLE SOLE
Technical Field
The present invention relates to a vapor-permeable shoe with
waterproof and vapor-permeable sole.
Background Art
As is known, the part of the foot that has the greatest perspiration
effect is the sole of the foot.
Therefore, the region of the shoe where moisture caused by sweating
can accumulate the most is the interface between the sole of the foot and the
sole of the shoe.
There, the sweat generated saturates the air with humidity and mostly
condenses, stagnating on the plantar insert.
Only a small amount of the moisture produced by sweating spreads to
the sides of the upper and exits from them if they are vapor-permeable.
Such effect of sweat stagnation in the plantar region is particularly
conspicuous in rubber-sole shoes; in these cases vapor permeation through
the sole of the shoe is in fact prevented by its total impermeability.
As is known, the stagnation of sweat in the plantar region causes to
the user of the shoe a feeling of discomfort and also constitutes a
preferential site for the growth of bacterial cultures, which are known to be
the source of bad odors.
Therefore, it is a commonly felt need to obviate the stagnation of
moisture from sweating at the plantar region of shoes.
A first attempt aimed at meeting this need consists of the solution
disclosed in EP 0382904.
The teaching contained in such patent consists in dividing the rubber
sole into two layers, the lower one of which has through micro-perforations,
and in interposing thereat a semipermeable membrane which is joined
perimetrically to the two layers, in order to avoid water infiltrations and
thus
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to obtain a sole that is impermeable to water in the liquid state and
permeable to water vapor.
For the sake of simplicity, hereinafter an element with the property of
being impermeable to water in the liquid state and permeable to water vapor
is referenced as waterproof and vapor-permeable.
The semipermeable membranes that EP 0382904 teaches to use are
for example of the type disclosed in US 4,187,390 and US 4,194,041 by W.
L. Gore or US 6,228,477 by BHA Technologies.
Such membranes are provided by means of thin films which are made
of expanded polytetrafluoroethylene, e-PTFE, with thicknesses that vary
generally from 19 microns to 70 microns, and are waterproof and vapor-
permeable.
Their microstructure is characterized by the presence of dense areas,
called nodes, interconnected by stretched filaments known as fibrils.
These semipermeable membranes, conceived initially for the military
field, have been developed and used in the clothing and footwear field in
order to avoid the accumulation of vapor from sweating in items of clothing
and to provide shoes with uppers with waterproof and vapor-permeable
linings.
Because the market of the clothing and footwear field has always
demanded soft and comfortable items, in the described applications there is
a strong need to ensure that the membrane, intended as a functional layer,
does not compromise such characteristics.
This need has been expressed in a true technical preconception that
has entailed the use of membranes provided with low thicknesses in order to
be laminated with supporting and/or aesthetic finishing materials, such as
fabric or leather, so as to obtain finished laminated elements that have
considerable characteristics of flexibility, easy folding, softness, surface
slipperiness, compressibility and extensibility, and low weight per unit
surface.
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However, the films that provide such membranes have poor
characteristics of mechanical strength, indeed because of their low
thickness.
In fact, it should be noted that the value of the strength of the
lamination mainly derives from the characteristics of the fabric layer or
supporting layer to which the membrane is coupled.
In particular, available films made of polymeric materials, used to
provide such membranes as mentioned, have thicknesses generally between
19 and 70 microns, which give them poor penetration resistance, i.e., less
than 5 N.
The expression "penetration resistance" designates the characteristic
defined by a measurement performed according to the method illustrated in
the ISO 20344 ¨ 2004 standard, chapter 5.8.2 "Determination of the
penetration resistance of the sole" regarding safety footwear.
This poor mechanical penetration resistance has led the inventor of
EP 0382904 to prevent contact of the membrane with foreign objects by
limiting the diameter of the holes of the sole that the membrane faces.
This solution, however, has been shown to limit the area of the sole
assigned to vapor permeation and moreover the holes can become
obstructed.
The teaching disclosed in EP 858,270, by the same Applicant,
discloses a solution aimed at overcoming these drawbacks, but is not yet
completely without aspects that can be perfected.
Said patent discloses a shoe with a sole that is made of perforated
elastomer and comprises a mid-sole that comprises a waterproof and vapor-
permeable membrane that is superimposed on a lower protective layer,
preferably made of felt, which is treated in order to be water-repellent.
Since the protective layer is not made of waterproof material, it is not
possible to provide a direct seal of the mid-sole with the sole, but a
waterproof peripheral element is used which provides a sealing bridge
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between the waterproof and vapor-permeable membrane and the sole.
As mentioned, this invention, while allowing an efficient protection
of the membrane against the penetration of foreign objects, has some
aspects that can be perfected.
In particular, the protective element loses progressively its water-
repellent characteristics and therefore tends to become saturated with water
and/or mud or other types of dirt, absorbed through the holes of the tread,
compromising the breathability of the sole and creating, moreover, an
environment favorable to the proliferation of microorganisms, such as
molds and bacteria, which can cause the shoe to have a bad odor.
Another drawback consists in that during use the cyclic flexing and
traction to which the mid-sole is subjected while walking tends to cause
progressive wear and tearing of the membrane, thus causing the sole to lose
its waterproofness.
A further solution is proposed in US 6508015 by Rauch Max, which
discloses a sole structure with two superimposed layers, the topmost of
which, designed to be directed toward the upper part of the shoe, is elastic
and permeable to water vapor.
The lower layer, which covers less than 70% of the upper layer, has a
function of support thereof and provides the tread.
The upper layer is made for example of sintered plastics or non-
woven fabrics so as to have a microporous structure, which in any case is
not waterproof.
A drawback of this solution consists in that during use of the shoe the
microporous upper layer, left extensively exposed by the lower layer, tends
to become saturated with water when it comes into contact with it,
absorbing it, retaining it and partly releasing it over time, dirtying the
surfaces on which one walks.
Moreover, the upper layer tends to degrade in contact with the
absorbed water.
5
In order to obtain the waterproofness of the sole, such patent
discloses the teaching of treating the upper layer so as to make it water-
repellent or cover it with a waterproof and vapor-permeable membrane
arranged above it.
However, the hydrophobic treatment has a short life, causing the sole
to lose its waterproofness, whereas the application of a vapor-permeable and
waterproof membrane over the upper layer in fact reproduces a structure
that can be likened to the one already described, in which the membrane is
supported by one or more protective layers, therefore facing again the same
drawbacks and limitations in quantitative terms of vapor permeability.
Disclosure of the Invention
The aim of the present invention is to provide a vapor-permeable shoe
with waterproof and vapor-permeable sole that allows to overcome the
limitations of currently known shoes and soles, particularly by allowing to
prevent the retention and release of the water with which it might come into
contact during use, at the same time having an efficient and durable vapor-
permeability and waterproofness.
Within this aim, an object of the invention is to devise a vapor-
permeable shoe with waterproof and vapor-permeable sole which, with
respect to currently known products, has a greater resistance to the damage
caused by foreign objects that, during its use, tend to penetrate its sole,
such
as for example pebbles, particularly if they are sharp, or the like.
Another object of the invention is to provide a vapor-permeable shoe
with waterproof and vapor-permeable sole whose waterproofness and vapor
permeability are more durable than in currently known products.
According to an aspect of the present invention there is provided a vapor-
permeable shoe with waterproof and vapor-permeable sole, comprising
¨ an upper assembly,
¨ a sole, which is joined to said upper assembly and comprises a body
made of waterproof material which has a tread and has at least one region that
is
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permeable to water vapor,
¨ at least one waterproof and vapor-permeable membrane, which covers
said at least one region, toward the inside of said shoe,
¨ at least one protective element, which covers at least partially the lower
face of said at least one membrane, whereby said shoe comprises at least one
protective shield which is vapor-permeable, covers said at least one region
and is
substantially interposed between said region and said at least one protective
element,
said protective shield being sealed in a waterproof manner to said body at at
least
one zone of said body that is peripheral to said at least one region wherein a
peripheral portion of said at least one membrane is sealed impermeably to said
body
and wherein said protective shield is waterproof.
Brief description of the drawings
Further characteristics and advantages of the invention will become
better apparent from the description of preferred but not exclusive
embodiments of the waterproof and vapor-permeable sole according to the
invention, illustrated by way of non-limiting example in the accompanying
drawings, wherein:
Figure 1 is a transverse sectional view of a vapor-permeable shoe
according to the invention, in a first embodiment;
Figure 2 is a transverse sectional view of a vapor-permeable shoe
according to the invention, in a second embodiment;
Figure 3 is a transverse sectional view of a vapor-permeable shoe
according to the invention, in a variation of the second embodiment;
Figure 4 is a transverse sectional view of a vapor-permeable shoe
according to the invention, in a third embodiment.
Ways of carrying out the Invention
With reference to the figures, a vapor-permeable shoe with
waterproof and vapor-permeable sole is generally designated by the
reference numeral 10 in a first embodiment, which comprises
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¨ an upper assembly 11,
¨ a sole 12, which is joined to the upper assembly 11 and comprises a
body 13 made of waterproof material which has a tread 14 and has at least
one region 15 that is permeable to water vapor,
¨ a waterproof and vapor-permeable membrane 16, which covers a
region 15, toward the inside of the shoe 10,
¨ a protective element 17, which covers a lower face 16a of the
membrane 16.
According to the invention, the shoe 10 has the peculiarity in that it
comprises moreover a protective shield 18, which is waterproof and vapor-
permeable, covers the region 15 and is substantially interposed between
such region and the protective element 17, the protective shield 18 being
sealed in a waterproof manner to the body 13 at a zone 13a of the body 13
that is peripheral to the region 15, preferably as described hereinafter.
The tread 14 is conveniently the lower surface of the body 13 that,
when in use, makes contact with the ground, but in an equivalent manner in
alternative embodiments of the invention it can be an element that is
separate from said body 13 and associated with it in a downward region.
Conveniently, the region 15 is defined by a plurality of holes 15a that
pass through the body 13.
In alternative embodiments of the invention, in a substantially
equivalent manner, said region can be defined by at least one wide opening,
in which structural elements for reinforcement and support for said
protective shield, for example in order to form a grid, can be provided.
Depending on the contingent requirements, in alternative
embodiments of a vapor-permeable shoe according to the invention, the
shoe comprises a sole that generally has at least one region that is permeable
to the water vapor and is covered by at least one waterproof and vapor-
permeable membrane, below which at least one protective element is
provided, at least one of said protective shield being moreover provided at
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said at least one region.
Advantageously, the protective shield 18 is microporous and has
pores with an average aperture of less than 1 um; preferably, said pores
have an average aperture of less than 0.5 um and in particular conveniently
at least 50% of said pores has an average aperture of less than 0.5 um.
Advantageously, the protective shield 18 is constituted by a sheet
made of material obtained from a substantially uniform mixture composed
of
¨ a polyolefin with high molecular weight, in a percentage concentration of
the volume of said mixture comprised between 8% and 98%,
¨ a filler, which is adapted to promote the formation of micropores, in a
percentage concentration of the volume of said mixture comprised between
1% and 92%,
¨ a plasticizer, in a percentage concentration of the volume of said
mixture
comprised between 1% and 40%.
Where said polyolefin is preferably a UHMW polyethylene (UHMW
meaning Ultra High Molecular Weight) and conveniently said filler is
selected between silicon dioxide and silicic acid, said plasticizer is a water-
insoluble oil, preferably petrol oil.
As an alternative, the protective shield 18 is conveniently made of a
material selected among expanded polytetrafluoroethylene, e-PTFE,
polyurethane, PU, polyester, PES, polypropylene, PP, polyethylene, PE, and
the like.
Preferably, the protective shield 18 has a structure selected among
- a structure constituted by a single integral layer, which is preferably
extruded, having a thickness substantially comprised between 0.1 and 5 mm,
¨ a structure constituted by a plurality of layers joined by lamination
to form a multilayer element whose thickness is substantially comprised
between 0.1 and 5 mm,
- a structure constituted by a plurality of laminated layers, a
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permeable material being provided between them and being cohesive with
them.
The protective element 17 is conveniently made of a material that is
resistant to hydrolysis and vapor-permeable, selected among felt, non-
woven fabric and the like, treated so as to be water-repellent, and
conveniently of a thickness substantially comprised between 0.5 mm and 5
mm.
The membrane 16 is conveniently of the type of commonly
commercially available vapor-permeable and waterproof membranes, for
example made of expanded polytetrafluoroethylene, e-PTFE, polyurethane,
PU, or the like, and at least one mesh that reinforces it is conveniently
associated therewith.
Moreover, advantageously an element 19 is provided for sealing the
peripheral portion 16b of the membrane 16 to the body 13 that conveniently
connects in a bridge-like manner its laterally adjacent edges, sealing them to
each other.
By way of non-limiting example, the portion in which the sealing
element 19 provides the waterproof seal of the peripheral portion 16b of the
membrane 16 to the body 13 is shown in Figure 1 by means of a segment of
a dot-and-dash line, designated by the reference letter A.
The sealing element 19 is made advantageously of waterproof
polymeric material and adheres hermetically to the peripheral portion 16b of
the membrane 16 and to the body 13 with a layer of glue that is resistant to
hydrolysis and capable of ensuring an effective seal, preferably of the
polyurethane type.
The waterproof polymeric material of which the sealing element 19 is
made is conveniently polyvinyl chloride, PVC, or thermoplastic
polyurethane, TPU, or the like.
In alternative and substantially equivalent embodiments, the sealing
element is advantageously a film of hot-melt thermoplastic adhesive, made
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of polyurethane or polyester, polyamide or polyolefin, that can be activated
by means of heat and pressure.
A film that is particularly suitable for providing said sealing element
is marketed by the company Bemis Associates Inc with product code 3218,
5 or by the company Collano AG, XIRO Adhesive Films with product code
XAF 36.004 (Puro).
Moreover, in a further and alternative method of embodiment of the
sealing element, in a substantially equivalent manner, such element is
provided by the material that constitutes the body of the sole, joined so as
to
10 foim a waterproof seal at the peripheral region of the membrane.
Advantageously, the protective shield 18 and the body 13 are
connected as to form a waterproof seal, conveniently at the zone 13a that is
peripheral to the region 15.
Said waterproof seal connection is preferably provided by adhesive
bonding or by high-frequency welding.
As an alternative, depending on the contingent requirements of
embodiment of the invention, said sealing connection is conveniently
provided by gripping to the protective shield 18 of the material for
providing the body 13 injected in a mold during the formation step.
In particular, in this case, said sealing connection is obtained by co-
molding on the protective shield 18 the material that forms the body 13, or a
component thereof such as, for example, if it is formed by a lower portion
and by a mid-sole.
In this manner, in fact, the material that forms the body 13, or its
component, grips the protective shield 18 so as to form a waterproof seal,
conveniently at the zone 13a of the body 13, which is peripheral to the
region 15 that is permeable to water vapor.
In the accompanying figures, by way of non-limiting example, said
sealing connection is illustrated by way of a dot-and-dash line designated by
the reference letter B.
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Advantageously, the upper assembly 11, the profile of which is
shown schematically in dashed lines in Figures 1, 2 and 3, depending on the
actuation requirements of the invention, comprises at least
¨ an outer vapor-permeable upper,
- an inner vapor-permeable lining, and
¨ a vapor-permeable insole, to which the lower flaps of the upper and
of the lining are joined in a per se known manner, for example according to
a lasting construction or by sewing, for example of the Strobel type.
In Figures 1, 2 and 3, the upper assembly 11 is shown schematically
in dashes and the upper, the lining and the insole are not shown, because
they are per se known elements whose structure is advantageously selected
among known ones in a manner that is consistent with the contingent
requirements of execution of the invention.
Preferably, a spacer 20 is provided that covers the upper face 16c of
the membrane 16.
The main purpose of the spacer 20 is to protect the membrane 16
against the possible abrasive action of the insole, being interposed between
them.
Conveniently, the spacer 20 is made of vapor-permeable or perforated
material, for example felt, or fabric or polymeric material or cellulose
material.
In a second embodiment of a shoe according to the invention,
illustrated by way of non-limiting example in Figure 2, where it is
designated by the reference numeral 100 and where the elements that
correspond to those described so far are also designated by the same
reference numerals, the body 13 advantageously comprises a lower portion
21 and an upper portion 22, the protective shield 18 being sealed to the
lower portion 21, in which the zone 13a is peripheral to the region 15.
Conveniently, the upper portion 22 is joined so as to provide a
waterproof seal to the peripheral portion 16b of the membrane 16.
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Said waterproof sealing joint, illustrated by way of non-limiting
example in Figures 2 and 3 by a segment of dot-and-dash line designated by
the reference letter C, is preferably provided by glueing or, as an
alternative,
according to the contingent requirements of execution of the invention, is
conveniently provided by gripping to the peripheral portion 16b of the
membrane 16 of the material for providing the upper portion 22 injected in a
mold during the step for forming the sole 13.
In particular, in this case, said sealed connection is obtained by co-
molding on the peripheral portion 16b the material that forms the upper
portion 22.
In particular, the sole 100 preferably comprises a spacer 20 that is
permeable to water vapor and superimposed on the membrane 16 in order to
cover it to protect it against any abrasive action that the insole may apply
to
it during use of the shoe 10.
Advantageously, the spacer 20 is made of vapor-permeable or
perforated material, for example felt or fabric or plastics or cellulose
material.
If the upper portion 22 is provided by co-molding, advantageously the
spacer 20 also acts as a barrier to the passage, toward the membrane 16, of
the material for providing the upper portion 22 during injection in the mold.
In an alternative constructive variation, not shown in the
accompanying figures, the spacer is replaced by a central portion of said
upper portion, which has holes or through openings so as to be permeable to
water vapor, so as to define part of said region, of said body of the sole,
that
is permeable to water vapor.
In said alternative variation, the lower portion of the sole body is
completely covered by the upper portion of the sole body.
With particular reference to Figure 3, in a variation of said second
embodiment, in a shoe according to the invention, designated by the
reference numeral 100a, the protective shield 18 advantageously has a
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perimetric band 18a that is exposed by the protective element 17 and by the
membrane 16 that it covers in a downward region.
At said perimetric band 18a, the protective shield 18 is associated so
as to provide a waterproof seal with the upper portion 22 of the body 13 of
the sole 12.
Said waterproof sealing association, illustrated by way of non-
limiting example by means of a a dot-and-dash segment designated by the
reference letter D in Figure 3, is conveniently provided by glueing or, in
case of formation of the upper portion 22 by co-molding, by gripping to the
perimetric band 18a of the material for providing the upper portion 22,
injected in a mold.
In a third embodiment of a vapor-permeable shoe with waterproof and
vapor-permeable sole according to the invention, illustrated by way of non-
limiting example in Figure 4, where it is generally designated by the
reference numeral 200 and where the elements that correspond to the ones
described so far are designated by the same reference numerals, the upper
assembly 11 comprises conveniently an outer vapor-permeable upper 23, a
vapor-permeable lining 24 and a vapor-permeable insole 25.
Generally, depending on the contingent requirements, the upper
assembly comprises conveniently at least one upper, one lining and one
insole which are vapor-permeable.
Advantageously, the membrane 16 constitutes a lower layer of the
insole 25 or, in a substantially equivalent manner, is conveniently associated
with a layer of the insole 25.
The lower flaps of the upper 23 and of the lining 24 are conveniently
jointed to the insole 25, preferably by means of stitched seams.
In this case, the peripheral portion 16b of the membrane 16 and the
body 13 of the sole 12 are connected so as to provide a waterproof seal
conveniently by means of the material for providing the body 13, or a
component thereof, which grips so as to provide a waterproof seal the
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peripheral portion 16b when the body 13 is formed by co-molding on the
upper assembly 11.
As an alternative, the peripheral portion 16b of the membrane 16 and
the body 13 of the sole 12 are connected so as to provide a waterproof seal
conveniently by glueing the membrane 16 to the body 13 of the sole 12, or
to a component thereof, such as a mid-sole.
Moreover, the protective shield 18 and the body 13 are
advantageously connected so as to provide a waterproof seal at the zone
13a, which is peripheral to the region 15 that is permeable to water vapor.
The sealed connection between the membrane 16 and the body 13 of
the sole 12 is illustrated by way of non-limiting example in Figure 4 with a
segment of a dot-and-dash line designated by the reference letter E.
Thus, the sealed connection between the protective shield 18 and the
body 13 of the sole is illustrated by way of non-limiting example in Figure 4
with a segment of a dot-and-dash line designated by the reference letter B,
by analogy with what has been described so far.
Advantageously, the waterproof sealed connection of the body 13 to
the protective shield 18 is provided by gluing or co-molding the material
that constitutes the body 13, as already described with reference to the
sealed connection of the body 13 to the membrane 16.
In practice, it has been found that the invention achieves the intended
aim and objects, by providing a vapor-permeable shoe with waterproof and
vapor-permeable sole that allows to overcome the limitations of currently
known shoes and soles, particularly allowing to prevent the retention and
the release of water with which the sole might come into contact during use,
thanks to the presence of the protective shield, which by being impermeable
to water and sealed to the body of the sole prevents the water from reaching
the protective element of the membrane, though being vapor-permeable.
Moreover, a vapor-permeable shoe with waterproof and vapor-
permeable sole according to the invention, with respect to currently known
15
products, has a greater resistance to the damage that can be induced by
foreign objects which, during its use, tend to penetrate its sole, such as for
example pebbles, particularly if sharp, or the like; in fact even in case of
penetration of the protective shield, the membrane, protected by the
protective element, preserves the waterproofness and the vapor permeability
of the sole.
A shoe with waterproof and vapor-permeable sole according to the
invention also has a more durable waterproofness and vapor-permeability
than currently known products, thanks to the collaboration of the membrane
and of the protective shield, which cooperate in protecting the
waterproofness of the sole and are moreover vapor-permeable.
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 used, so long as they are compatible with the
specific use, as well as the contingent shapes and dimensions, may be any
according to requirements and to the state of the art.
Where technical features mentioned in any claim are followed by
reference signs, those reference signs have been included for the sole
purpose of increasing the intelligibility of the claims and accordingly such
reference signs do not have any limiting effect on the interpretation of each
element identified by way of example by such reference signs.
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