WATERPROOF FOOTWEAR. AS WELL AS PROCESS AND LAST FOR ITS

MANUFACTURE

The present invention relates to waterproof footwear, and in particular to footwear provided with a semipermeable or breathable waterproof upper, i.e. impermeable to water and permeable to water vapor. The present invention also relates to a process and a last for manufacturing said footwear.

Known footwear of the firm Aerosoles ^® is manufactured with a particular technique, in which the upper is turned inside out and its lower edge is sewn to a perimetric wall arranged around the upper surface of an elastomeric sole, so that this perimetric wall can be bent inwards and joined to the upper surface of the sole before the upper is turned inside out again.

However, waterproof footwear cannot be manufactured with this technique, since uppers waterproofed with chemical treatments and/or lined with waterproofing membranes would also be sewn to the sole along their lower edge, so that water would leak through the holes of these seams.

It is therefore an object of the present invention to provide waterproof footwear which can be manufactured with said technique. Said object is achieved with a footwear, a process and a last, the main features of which are disclosed in claims 1, 10 and 24, while other features are disclosed in the remaining claims.

Thanks to the process according to the present invention, footwear manufactured with the Aerosoles ^® technique can be waterproofed in a simple and quick manner. As a matter of fact, with this process one or more waterproofing membranes can be applied to the inner surface of the upper when the latter is turned inside out, thereby avoiding in any case water penetrations along the seam between upper and sole.

According to a particular aspect of the invention, the lower edge of the waterproofing membrane is joined to the upper surface of the sole and/or to its perimetric wall by means of one layer of glue, preferably polyurethane glue, so as to reduce the manufacture times and costs. The process according to the present invention can further be optimized thanks to a particular last which can be arranged into the upper turned inside out during the

pressing of the perimetric wall onto the sole and/or of the waterproofing membrane to the upper.

Finally, the pressing step of the process according to the present invention can be carried out with a press with deformable plates as disclosed in WO 02/11571 or WO 2004/112525, so as to further reduce the manufacture times. During this step the footwear is preferably turned upside down, so as to improve the application of the waterproofing membrane to the upper.

Further advantages and features of the footwear, the process and the last according to the present invention will become clear to those skilled in the art from the following detailed and non-limiting description of an embodiment thereof with reference to the attached drawings, wherein:

- figure 1 shows a partial view in a longitudinal section of the footwear during a first step of the manufacture process;

- figure 2 shows a cross-sectioned view along plane H-II of figure 1; and - figures 3 to 8 show cross or longitudinal section views of the footwear of figure 1 during subsequent steps of the manufacture process.

Referring to figures 1 and 2, it is seen that the footwear according to the present invention comprises in a known way a sole 1 made of an elastomeric material, for example rubber, PVC or polyurethane, which includes at least one perimetric wall 2 arranged around its upper surface Ia. An upper 3 is arranged inside out outside sole 1, so that the outer surface of upper 3 is turned toward sole 1, while the lower edge 3a of upper 3 is temporarily turned upwards and is arranged adjacent to the outer surface of the perimetric wall 2. Upper 3, being turned inside out, may thus temporarily protrude under sole 1. A seam 4 joins the perimetric wall 2 of sole 1 with the lower edge 3a of upper 3. Sole 1 can be lightened by a plurality of alveoli 5.

Figure 3 shows a second step of the process according to the present invention, wherein at least one waterproofing membrane 6 is arranged around upper 3, so as to cover at least partially the inner surface of upper 3 turned outwards. The lower edge 6a of the waterproofing membrane 6 is temporarily turned upwards. The waterproofing membrane 6 is preferably semipermeable or breathable, i.e. impermeable to water and permeable to water vapor, in particular with a permeability to water vapor greater than

400 g/m ² * 24h. The waterproofing membrane 6 is further preferably elastic with an elongation degree greater than 50% and is made of a polymeric material, for example PTFE, polyurethane or polyester. The waterproofing membrane 6 can also be coupled with an inner lining, which is temporarily turned to the side opposite to upper 3, so that the membrane is comprised between upper 3 and this lining. A first layer of glue 7, in particular polyurethane glue, is applied onto the inner surface of the perimetric wall 2 and/or onto the upper surface Ia of sole 1 along the perimetric wall 2.

Figure 4 shows a third step of the process according to the present invention, wherein the lower edge 6a, temporarily turned upwards, of the waterproofing membrane 6 is bent in the direction of the arrows around the lower edge 3 a of upper 3 and around the perimetric wall 2 of sole 1, so as to cover at least partially the inner surface of the perimetric wall 2 and to be joined by means of the first layer of glue 7 to this inner surface and/or to the upper surface Ia of sole 1 along the perimetric wall 2. A second layer of glue 8, in particular polyurethane glue, is applied onto the inner surface of the lower edge 6a of the waterproofing membrane 6 and/or to the upper surface Ia of sole 1 along the perimetric wall 2.

Figures 5 and 6 show a fourth step of the process according to the present invention, wherein a last 9 having an upper surface complementary with the lower surface of sole 1 and lateral surfaces complementary with the outer surface of upper 3 temporarily turned inwards is arranged in contact with sole 1 within upper 3, after which a press 10 bends inwards, presses onto the upper surface Ia of sole 1 and bonds on this upper surface by means of the second layer of glue 8 the perimetric wall 2 of sole 1 joined to the lower edge 3a of upper 3. The lower edge 6a of the waterproofing membrane 6 is thus comprised between the perimetric wall 2 bent inwards and the upper surface Ia of sole 1.

Figure 7 shows a fifth step of the process according to the present invention, wherein sole 1 joined to upper 3 and to the waterproofing membrane 6 is temporarily turned upside down, so that last 9 is arranged on sole 1. This whole is then arranged onto a support 11 for being pressed in a press with deformable plates 12 and 13, so as to press upper 3 against last 9 and/or sole 1. During this pressing step, the waterproofing membrane 6 adheres to the inner surface of upper 3 by means of a discontinuous or

continuous layer of adhesive arranged between membrane 6 and upper 3. Said adhesive can be applied in a dot matrix onto the outer surface of the waterproofing membrane 6 and/or comprise polyurethane glue, so that upper 3 remains breathable if the waterproofing membrane 6 is semipermeable. Figure 8 shows a sixth step of the process according to the present invention, wherein last 9 is removed and upper 3 is turned inside out, so that its outer surface is turned outwards and its inner surface, provided with the waterproofing membrane 6, is turned inwards. Also the inner lining, if any, of the waterproofing membrane 6 is thus turned inwards. An insole 14 can be applied on sole 1 and the bent perimetric wall 2. Possible variations and/or additions may be made by those skilled in the art to the hereinabove described and illustrated embodiment of the invention while remaining within the scope of the following claims.