U.S. patent application number 11/718117 was filed with the patent office on 2009-02-19 for footwear.
Invention is credited to Philip Ross Bagnall, Brendan Hanwell, Michael John O'Connor.
Application Number | 20090044432 11/718117 |
Document ID | / |
Family ID | 35516076 |
Filed Date | 2009-02-19 |
United States Patent
Application |
20090044432 |
Kind Code |
A1 |
O'Connor; Michael John ; et
al. |
February 19, 2009 |
FOOTWEAR
Abstract
An outsole unit for an item of footwear comprises a base layer
of a flexible material having fibres extending from one surface,
for example a napped leather such as pigskin suede or a textile
material, and one or more lugs of thermoplastic polyurethane (TPU)
moulded directly to the fibrous surface so as to form a tread.
Multiple lugs may form a regular array separated by grooves, and
may be connected solely by the base layer, by a skin of TPU
extending across the base layer or by narrow connecting elements of
TPU. An upper of an item of footwear may comprise a backing of
suede leather with a grid of strips of TPU moulded to its napped
surface. An item of footwear may comprise the outsole unit of the
invention, the upper of the invention, or both.
Inventors: |
O'Connor; Michael John;
(County Galway, IE) ; Bagnall; Philip Ross;
(County Offaly, IE) ; Hanwell; Brendan; (Fort
Augustus, GB) |
Correspondence
Address: |
HESLIN ROTHENBERG FARLEY & MESITI PC
5 COLUMBIA CIRCLE
ALBANY
NY
12203
US
|
Family ID: |
35516076 |
Appl. No.: |
11/718117 |
Filed: |
November 1, 2006 |
PCT Filed: |
November 1, 2006 |
PCT NO: |
PCT/GB2006/004077 |
371 Date: |
April 27, 2007 |
Current U.S.
Class: |
36/30R ; 12/146B;
12/146R |
Current CPC
Class: |
A43B 13/141 20130101;
B29D 35/146 20130101; A43B 13/16 20130101; A43B 13/223 20130101;
A43B 3/0078 20130101; A43B 13/026 20130101; A43B 13/12 20130101;
A43B 23/026 20130101; A43B 23/24 20130101; A43B 3/0057 20130101;
B29D 35/142 20130101 |
Class at
Publication: |
36/30.R ;
12/146.B; 12/146.R |
International
Class: |
A43B 13/12 20060101
A43B013/12; A43D 8/00 20060101 A43D008/00; A43B 13/00 20060101
A43B013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 1, 2005 |
GB |
0522216.1 |
Jul 18, 2006 |
GB |
0614228.5 |
Claims
1-28. (canceled)
29. An outsole element for an item of footwear comprising a lamina
of a flexible material having a plurality of fibrous elements
extending from a lower, in use, surface thereof and a plurality of
ground contact bodies containing a thermoplastics polyurethane
composition molded directly to said lower surface of the
lamina.
30. The outsole element according to claim 29, wherein said lamina
comprises a leather material having a nap on said lower
surface.
31. The outsole element according to claim 29, wherein said lamina
comprises a sheet of a woven textile fabric.
32. The outsole element according to claim 29, wherein said ground
contact bodies are connected, each to the others, by the lamina
alone.
33. The outsole element according to claim 29, wherein said ground
contact bodies are connected by linking elements.
34. The outsole element according to claim 29, wherein the ground
contact bodies are linked by a skin of said thermoplastics
polyurethane composition molded to the lamina and extending between
the bodies.
35. The outsole element according to claim 29, wherein said ground
contact bodies comprise a substantially regular array.
36. The outsole element according to claim 29, wherein the lamina
comprises a marginal portion adapted to be sewn to a remainder of
the item of footwear.
37. The outsole element according to claim 29, incorporated into an
item of footwear.
38. A method of producing an outsole for an item of footwear,
comprising the steps of providing a lamina of a flexible material
having a plurality of fibrous elements extending from a first
surface thereof and molding a plurality of ground-contact bodies
comprising a thermoplastic polyurethane composition to said first
surface.
39. A method of producing an insole according to claim 38,
comprising the steps of providing a sheet of leather material
having a napped surface and molding said ground contact bodies to
said napped surface.
40. The method according to claim 38, comprising the further step
of treating the napped surface prior to said molding step to reduce
an oil content of the napped surface.
41. The method according to claim 38, comprising the steps of
providing a sheet of woven textile fabric and molding said
plurality of ground contact bodies to one surface of said sheet of
woven textile fabric.
42. The method according to claim 38, comprising the steps of
providing a liquid composition curable to form a thermoplastic
polyurethane composition, molding said composition to the lamina
and curing the composition in contact therewith.
43. A material adapted to be used in the production of uppers for
footwear comprising a first layer of a base material having a
plurality of fibrous elements extending from a first surface
thereof and molded directly to said first surface an apertured
second layer of a composition comprising a thermoplastic
polyurethane compound.
44. A material according to claim 43, wherein said base material
comprises a leather material having a nap on one surface and said
apertured layer is molded to said napped surface.
45. A material according to claim 43, wherein the apertured second
layer comprises a continuous layer of said composition having a
plurality of apertures extending therethrough.
46. A material according to claims 43, wherein the apertured second
layer comprises a plurality of intersecting elongate elements
defining apertures therebetween.
47. A material according to claim 43, wherein the apertured second
layer is discontinuous, said second layer comprising a plurality of
unconnected zones of said polyurethane composition.
48. A material according to claim 43, incorporated into an upper
for an item of footwear.
49. A method of producing a material to be used in the production
of uppers for footwear comprising the steps of providing a base
material having a plurality of fibrous elements extending from a
first surface thereof and molding an apertured layer of a
composition of a thermoplastic polyurethane compound to said first
surface.
50. The method according to claim 49, comprising the steps of
providing a sheet of leather material having a napped surface and
molding said apertured layer to said napped surface.
51. The method according to claim 50, comprising the further step
of treating the napped surface prior to said molding step to reduce
its oil content.
Description
[0001] The present invention relates to improvements to footwear
and components for footwear, and to improved methods for their
production. More particularly, but not exclusively, it relates to
uppers and outsoles for footwear having improved wear properties
and with an improved appearance.
[0002] Uppers for footwear may be made from a wide range of
materials. Traditional leather uppers are relatively hardwearing
and comfortable to wear, and can "breathe", but require
considerable care to keep an attractive appearance. Sueded leather
uppers (including true suede and nubuck) are similarly comfortable
and "breathable", but the sueded surface may become shiny where it
experiences significant wear. The number of decorative effects that
can be achieved with suede or the like is also limited.
[0003] There is hence a need for a material from which uppers may
be produced that has the advantages of suede or the like, but with
fewer of the disadvantages. It would also be beneficial if this
material allowed a footwear designer to employ a greater range of
decorative effects.
[0004] Similarly, while outsoles for footwear have been the focus
for much innovation, existing sole units still have shortcomings.
For example, injection-moulded polyurethane outsoles are widely
used in trainers and other types of footwear. However, these may
not be very compliant to a particular wearer's foot shape, usually
being monolithic mouldings of a semi-rigid polyurethane composition
(softer compositions are too easily damaged on extraction from the
mould). Complex structures for outsoles and midsoles have been
tried, but these tend to add significantly to the cost of the
footwear. Another problem with such outsoles is that they usually
have to be mounted to a remainder of the footwear using adhesives.
The adhesives currently employed are not very pleasant to use and
queries have been raised concerning their environmental
soundness.
[0005] It is hence an object of the present invention to provide
uppers, sole components, footwear, materials from which they may be
made and/or methods for their production that obviate the above
problems and provide the above advantages.
[0006] According to a first aspect of the present invention, there
is provided a material adapted to be used in the production of
uppers for footwear comprising a first layer of a base material
having a plurality of fibrous elements extending from at least a
first surface thereof and moulded directly to said first surface an
apertured second layer of a composition comprising a thermoplastic
polyurethane compound.
[0007] Preferably, said base material comprises a leather material
having a nap on one surface, such as a suede or nubuck leather.
[0008] Said apertured layer may then be moulded to said napped
surface.
[0009] Said leather material may comprise an artificial or
synthetic leather material.
[0010] In a first embodiment, the apertured second layer comprises
a continuous layer of said composition having a plurality of
apertures extending therethrough.
[0011] Advantageously, the apertured second layer comprises a
plurality of intersecting elongate elements defining apertures
therebetween.
[0012] Said intersecting elements may be generally linear.
[0013] Said intersecting elements may be arranged in a regular
array.
[0014] The second apertured layer may then form a regular grid.
[0015] The apertured layer may comprise occasional unapertured
regions.
[0016] Preferably, the apertures together comprise at least a third
of the apertured layer by area, advantageously at least a half,
optionally at least two-thirds.
[0017] Preferably, each aperture has a minimum width of less than
ten millimetres, advantageously less than five millimetres,
optionally less than three millimetres.
[0018] In a second embodiment, the apertured second layer is
discontinuous, comprising a plurality of unconnected zones of said
polyurethane composition.
[0019] The base material and the thermoplastic polyurethane
composition may be of contrasting colours.
[0020] The thermoplastic polyurethane composition may have a Shores
hardness of less than 80 C.
[0021] According to a second aspect of the present invention, there
is provided a method to produce a material to be used in the
production of uppers for footwear, comprising the steps of
providing a base material having a plurality of fibrous elements
extending from at least a first surface thereof and moulding an
apertured layer of a composition of a thermoplastic polyurethane
compound to said first surface.
[0022] Preferably, the method comprises the steps of providing a
sheet of sueded leather or other leather material having a napped
surface and moulding said apertured layer to said napped
surface.
[0023] The method may then comprise prior to said moulding step the
further step of treating the napped surface to reduce its oil
content.
[0024] The method preferably comprises the steps of providing a
liquid composition curable to form a thermoplastic polyurethane
compound, moulding said composition to the base material and curing
said composition in contact therewith.
[0025] Advantageously, the method comprises the steps of providing
mould means adapted to define said apertured layer, introducing
said liquid composition into the mould means and so bringing the
base material and the mould means together as to contact the base
material with the liquid composition.
[0026] The method may comprise the step of mixing a plurality of
precursor materials to form said liquid composition.
[0027] According to a third aspect of the present invention, there
is provided an upper for an item of footwear comprising a material
as described in the first aspect above.
[0028] According to a fourth aspect of the present invention, there
is provided an outsole element for an item of footwear comprising a
lamina of a flexible material having a plurality of fibrous
elements extending from at least a lower, in use, surface thereof
and at least one ground contact body comprising a thermoplastic
polyurethane composition directly moulded to said lower surface of
the lamina.
[0029] Advantageously, said lamina comprises a leather material,
such as a suede or nubuck leather, having a nap on said lower
surface.
[0030] Said leather material may comprise an artificial or
synthetic leather material.
[0031] Alternatively, said lamina comprises a sheet of a woven
textile fabric.
[0032] Preferably, the outsole element comprises a plurality of
said ground contact bodies.
[0033] Advantageously, said ground contact bodies are connected,
each to the others, by the lamina alone.
[0034] Alternatively, said ground contact bodies are connected by
linking elements, optionally moulded integrally therewith.
[0035] The ground contact bodies may be linked by a skin of said
thermoplastic polyurethane composition moulded to the lamina and
extending between the bodies.
[0036] Preferably, said ground contact bodies comprise a
substantially regular array.
[0037] A gap between neighbouring ground contact bodies is
advantageously substantially narrower than a width of each said
body.
[0038] Preferably, the lamina extends outwardly of the at least one
ground contact body.
[0039] It may than comprise a marginal portion adapted to connect
the outsole element to a remainder of an item of footwear.
[0040] Said marginal portion may be adapted to be sewn to a
remainder of the item of footwear.
[0041] The thermoplastic polyurethane composition may have a Shores
hardness of less than 80 C.
[0042] According to a fifth aspect of the present invention, there
is provided an method to produce an outsole for an item of footwear
comprising the steps of providing a lamina of a flexible material
having a plurality of fibrous elements extending from at least a
first surface thereof and moulding at least one ground-contact body
comprising a thermoplastic polyurethane composition to said first
surface.
[0043] Preferably, the method comprises the steps of providing a
sheet of suede leather or other leather material having a napped
surface and moulding said at least one ground contact body to said
napped surface.
[0044] The method may then comprise prior to said moulding step the
further step of treating the napped surface to reduce its oil
content.
[0045] Alternatively, the method comprises the steps of providing a
sheet of woven textile fabric and moulding said at least one ground
contact body to one surface thereof.
[0046] The method preferably comprises the steps of providing a
liquid composition curable to form a thermoplastic polyurethane
composition, moulding said composition to the lamina and curing the
composition in contact therewith.
[0047] Advantageously, the method comprises the steps of providing
mould means adapted to define said at least one ground-contact
body, introducing said liquid composition into the mould means and
so bringing the lamina and the mould means together as to contact
the lamina with the liquid composition.
[0048] The method may comprise the step of mixing a plurality of
precursor materials to form said liquid composition.
[0049] According to a sixth aspect of the present invention, there
is provided an item of footwear comprising an upper as described in
the third aspect above.
[0050] According to a seventh aspect of the present invention there
is provided an item of footwear comprising an outsole element as
described in the fourth aspect above.
[0051] According to an eighth aspect of the present invention,
there is provided an item of footwear comprising an upper as
described in the third aspect above and an outsole element as
described in the fourth aspect above.
[0052] Preferably, the upper is sewn to the outsole element.
[0053] Embodiments of the present invention will now be more
particularly described by way of example and with reference to the
accompanying drawings in which:
[0054] FIG. 1 is an enlarged scrap plan view of a portion of a
first material comprising a shoe upper and embodying the present
invention;
[0055] FIG. 2 is a plan view from below of a first outsole
embodying the present invention;
[0056] FIG. 3 is a schematic cross-section of the outsole shown in
FIG. 2, taken along the line VII-VII;
[0057] FIG. 4 is a scrap cross-section of a second outsole
embodying the present invention;
[0058] FIG. 5 is a scrap cross-section of a third outsole embodying
the present invention;
[0059] FIG. 6 is a scrap plan view from below of a fourth outsole
embodying the present invention; and
[0060] FIG. 7 is a side elevation of a training shoe embodying the
present invention and comprising the outsole shown in FIG. 2.
[0061] Referring now to the Figures, and to FIG. 1 in particular, a
small area is shown of a first material 1 from which a shoe upper
may be produced. The first material 1 comprises a backing of a
conventional sueded leather 2 (here a pigskin suede). A grid of a
solid thermoplastic polyurethane composition has been applied
directly to a sueded face of the leather 2 by a moulding method
described below. In this case, the grid comprises a triangular grid
of first strips 3 of the polyurethane (PU) composition, with a
plurality of parallel second strips 4 of the PU composition
extending across each triangle defined by a trio of first strips 3.
The suede leather backing 2 is exposed between the second strips 4.
Occasional continuous zones 5 of the PU composition may be included
in the grid for decorative effect and/or to provide a location for
a logo or trade mark. However, even so, the first material 1
comprises a substantial proportion of uncovered suede leather 2
(here, well over half its area and possibly as much as two thirds
thereof).
[0062] The first material 1 is thus substantially as breathable as
any other suede leather and may be assembled into an upper using
the same methods as for conventional suede leather. However, the
grid of polyurethane strips 3, 4 mounted to its surface protects it
from wear (in this case, each triangle of the grid is roughly a
centimetre across, and the second strips 4 are spaced a millimetre
or two apart, so the suede 2 is well protected). This allows, for
example, suede leathers not of the very top quality to be used for
parts of an upper that may be more susceptible to wear (e.g. the
toe).
[0063] The visual effect of the slightly glossy parallel strips 4
of PU against the matt suede 2 background provides a further design
feature usable by a footwear designer, as does the possibility of
either sharply-contrasting or subtly-toned colours for the PU 3, 4
and the suede 2.
[0064] When the thermoplastic PU is moulded directly to a sueded
leather surface or the like it is found that there are no
noticeable loss-of-adhesion problems.
[0065] The particular PU grid 3, 4 shown in FIG. 1 is just one of
many patterns that may be laid down. For example, a hexagonal grid
both provides a striking visual effect and protects the suede 2
without covering an excessive proportion thereof.
[0066] While the first material 1 illustrated employs a continuous
apertured network of PU strips, discontinuous zones of PU may be
used instead where strength of the material is not a significant
issue.
[0067] The moulding process is carried out by providing a
horizontally-extending mould matrix for the desired pattern, and
filling its concavities with a liquid composition, which is curable
to form a thermoplastic polyurethane composition. The suede 2 or
other backing material is laid on top of the mould matrix, such
that its napped surface contacts an upper surface of the liquid
composition and is wetted thereby. The liquid composition is cured,
and once the cure is complete and the resultant TPU has cooled, the
suede 2 is removed from the mould matrix. The TPU is securely bound
to the surface of the suede 2 and releases easily from the mould
matrix.
[0068] The optimum liquid composition is produced by mixing two
liquid TPU precursors, which then begin to react together to form
cured TPU. The speed of reaction is selected such that the liquid
composition remains fluid and workable for long enough to be
introduced into the mould and to wet the suede or the like brought
into contact therewith. The heat of the reaction will keep the TPU
produced soft and malleable until the cure is complete; the heat
then dissipates.
[0069] Conventional TPU moulding techniques use pre-cured solid TPU
particles which are re-heated until soft, and then
injection-moulded to form a required shape. It is probable that the
high pressures involved in injection-moulding are necessary to
cause such re-heated cured TPU materials to flow satisfactorily
into a mould. The materials of the present invention do not require
significant pressure to force them into a mould; used at an early
stage of the cure, they will flow into a mould relatively easily,
and will fill any fine details of the mould matrix, should detailed
shapes be required.
[0070] Another advantage of the method of the present of the
present invention is that softer TPU compositions may be employed
than hitherto. The softest TPU compound in general use in the
footwear industry has a Shores hardness of 80 C or more; softer TPU
compounds are too difficult to de-mould, for example deforming
excessively or even tearing as they are removed from a mould. The
present method allows TPU compounds with Shores hardnesses in the
range of 55 C to 80 C to be used, and no significant de-moulding
problems are experienced.
[0071] The softer TPU compounds (particularly those in the range of
55 C to 70 C, it is believed) are superior in flex and grip, and
also appear to have better anti-abrasion properties than do the
harder TPU compounds used hitherto.
[0072] As well as pigskin suede, other time suede leathers derived
from cow hide or other animal skins may be used. Nubuck leathers
are equally useful, as are suede splits. Artificial suedes also
work satisfactorily. The common property appears to be a plurality
of fibres extending from one surface of the leather or simulated
leather, preferably a sufficient density of fibres to form a napped
surface.
[0073] The technique of directly moulding TPU to a surface of a
fibrous substrate is not only of use for materials to make footwear
uppers. It is probably of even greater benefit when employed to
produce sole components.
[0074] FIG. 2 shows a first outsole unit 15 for a training shoe or
the like, which comprises a base layer 16 of pigskin suede, to
which a plurality of separate blocks or lugs 17 of a solid
thermoplastic polyurethane composition have been directly moulded,
using a similar process to that described above. As for the
materials for the uppers, the TPU lugs 17 are moulded to the sueded
face of the pigskin suede 16. Once cured, the TPU composition is
similar to those conventionally used for ordinary outsole
mouldings, except that it is significantly softer (e.g. Shores
hardness 80 C).
[0075] In the first outsole unit 15, each lug 17 is generally
rectangular and they are separated each from the others by a grid
of first grooves 18 extending generally from heel to toe of the
outsole unit 15 and second grooves 19 extending generally
orthogonally thereto across the outsole unit 15. The exact shape of
each lug 17 varies according to its position on the outsole unit;
for example, lugs 17A that will be disposed beneath an arch of a
wearer's foot, on the "waist" of the sole, are relatively short and
narrow, while lugs 17H that will be disposed beneath a wearer's
heel are relatively long.
[0076] The grooves 18, 19 expose the suede base layer 16, with the
result that each TPU lug 17 may move substantially independently of
each other lug 17. Thus, when a wearer's weight is placed on the
first outsole unit 15, the lugs 17 can move and the base layer 16
flex or stretch to accommodate the wearer's particular foot shape
and the distribution of his or her weight across the foot both
statically and dynamically. This provides a far more natural feel
to a sole comprising the first outsole unit 15 than for a
conventional monolithic injection-moulded outsole. The smaller lugs
17A beneath the arch of the foot increase the outsole's flexibility
in this area, while the lugs 17H beneath the heel provide support
close to that of a conventional shoe heel.
[0077] The base layer 16 may alternatively comprise other sueded
leathers, such as nubuck, splits and the like (including artificial
suede, since breathability is not an issue for an outsole), or a
robust woven textile material if preferred. Note: it is known to
form conventional monolithic injection-moulded outsoles by
injection-moulding heated TPU through a textile fabric from its
upper, in use, face. This results in the textile fabric becoming
embedded in the TPU moulding, e.g. as a reinforcement. However, it
cannot be used on suede or tightly woven fabrics.
[0078] Moulding a curable liquid composition directly to a lower,
in use, face is simpler, more controllable and easily gives
sufficient adhesion, as long as the lower face is substantially
oil-free. This also allows the use of softer TPU compositions,
since soft TPUs are difficult to remove intact from conventional
injection-moulding moulds. TPUs with a Shores hardness of less than
80 C, and even as low as 55 C to 70 C, can be used, which give
better sole flexibility and grip than the conventional TPUs with
Shores hardness 80 C and above (even before the effect of the sole
structure described above is taken into account). The softer TPUs
also provide better abrasion resistance.
[0079] FIG. 3 shows further advantages of the first outsole unit
15. It is clear from this cross-section that the grooves 19,
extending as far as the flexible base layer 16, will allow the lugs
17 substantially independent movement. The base layer 16 comprises
a marginal zone 20 which extends outwardly from the outsole unit 15
to all sides (omitted from FIG. 2 for clarity). This marginal zone
20 may be used for mounting the outsole unit 15 to a remainder of a
shoe, etc, using conventional stitching techniques, whereas
conventional injection-moulded PU soles would almost certainly
require adhesives.
[0080] Also, an outsole unit 15 may be produced without being
restricted to a specific sole profile, because of the flexibility
of the base layer 16. This will be described in more detail in
respect of FIG. 7 below.
[0081] An alternative structure for a second outsole unit 21 is
shown in FIG. 4. In this, instead of the grooves 19 extending as
far as the base layer 16 so that the lugs 17 are wholly separate,
shallower grooves 22 are provided, so that a thin layer or skin 23
of TPU extends across substantially an entire lower surface of the
base layer 16. This may be preferred where the base layer 16 is not
inherently waterproof, for example, or may be preferred to increase
a TPU/base layer contact area for high-performance applications
where adhesion is of particular concern. The thin skin 23 does not,
however, couple the lugs 17 strongly together, so the second
outsole 21 has most of the flexibility, and the ability to conform
to a wearer's foot shape and gait, of the first outsole unit
15.
[0082] It is also possible, as shown in FIG. 5, to produce a third
outsole unit 24 in which a single monolithic TPU outsole 25 is
directly moulded to a lower (in use) surface of the base layer 16.
While this does not benefit from the very flexible tread surface
formed by the lugs 17 of the first and second outsole units 15, 21,
it can of course be provided with a conventional tread surface 26,
and will still have the benefit of the marginal zone 20 of its base
layer 16 for mounting to a remainder of the shoe. It may also
comprise a softer TPU composition than is possible with
injection-moulding.
[0083] Composite outsoles are also envisaged which have a plurality
of separate lugs 17 in some regions but monolithic elements 25 in
others (e.g. forming a conventional solid heel).
[0084] The lugs 17 may, as shown in FIG. 6 in respect of a fourth
outsole unit 27, be linked in a different fashion than that shown
in FIG. 4. In this case, neighbouring lugs 17 are linked by
connecting elements 28, 29 which may extend to the same height as
the lugs 17 (elements 29) or be slightly lower (elements 28). The
greater the cross-sectional area of each connecting element 28, 29,
the more strongly it constrains the respective lugs 17 to move as
one. Thus, the lugs 17 may be left to flex freely and independently
in some parts of the fourth outsole 27, while they are bound
(resiliently) together in others.
[0085] FIG. 7 shows a training shoe 30 comprising a first outsole
unit 15 mounted to an upper 31. The upper 31 and outsole unit 15
are directly mounted together by stitching through the marginal
zone 20 of the outsole unit 15, so no adhesives are required. The
upper 31 has been provided with a zone 32 of leather to support the
laces 33, and a reinforcement 34 around its toe area to give a
structured toecap.
[0086] FIG. 7 also shows how the flexible base layer 16 of the
outsole unit 15 allows it to adopt a required sole profile. It is
currently a common feature of trainer sole design for the outsole
to extend significantly up a toe and heel area of the shoe. Here,
lugs 17T at a toe end of the outsole unit 15 and lugs 17R at a rear
of a heel end thereof may both easily be wrapped around a
corresponding portion of the upper 31.
[0087] The training shoe 30 produced is thus lightweight,
comfortable in wear because of both the breathable upper 31 and the
flexible outsole unit 15, and straightforward to produce without
the need for adhesives.
[0088] Another type of footwear for which outsoles of the type
described would be particularly useful is children's shoes. The
flexible base layer 16 allows an outsole to stretch gradually as a
child's foot grows, where a conventional monolithic outsole might
restrict the growing foot.
[0089] The natural and synthetic suede leathers and the like,
listed above in respect of materials for uppers, can all be used as
the flexible base layer 16 of the outsole units 15, 21, 24, 27
described above.
[0090] A robust textile fabric may also be used, particularly in
situations where a waterproof sole is not required. In this case,
the yarns making up the textile will inevitably comprise a large
number of free fibre ends which extend away from the yarns
themselves (whether the yarns are spun from natural fibres,
synthetic fibres or a mixture of each). These "loose ends" appear
to be sufficient to ensure good bonding between the textile and the
TPU. Penetration of TPU into the textile weave is possible, but is
believed to have a secondary effect on the bonding (N.B. many suede
leathers and the like have only surface pits adjacent their fibres,
which may similarly augment the bonding of the TPU thereto).
* * * * *