HK1079968A - Waterproof footwear and process for its manufacture - Google Patents

Description

Waterproof footwear and process for making same

The present invention relates to waterproof footwear, and more particularly to footwear and boots having a waterproof upper and a waterproof sole made of plastic or rubber. The invention also relates to a manufacturing process of the shoe product.

The known waterproof footwear comprises a sole made by injection moulding with an insole sewn to the lower edge of the upper and of a protective lining, the lining comprising one or more textile layers with the addition of one or more semipermeable membranes, that is to say, such membranes allow the passage of water vapour but not water. The upper of these existing footwear, especially if made of leather, may absorb water, which therefore penetrates inwards through the seam of the upper with the insole, thus spreading around the protective lining.

To avoid this drawback, US4899465 discloses a waterproof footwear whose upper is connected to the insole by means of a perforated portion or a mesh, so that, during the moulding of the sole, a portion of plastic or rubber material separates the upper from the insole, preventing the passage of water through them. However, also with such existing footwear, water may pass through the upper, so as to be absorbed and spread by the outer fabric of the lining, and, if in a reduced manner, through the seam of the insole to the inside of the shoe. In addition, it is complicated to make holes in the upper, and the webbing is very wide and rigid, thus preventing the sole from bending.

To avoid these further discovered drawbacks, US patent 5505011 discloses a waterproof footwear similar to the one described above, except that the lower edge of the upper, which does not have a perforated or mesh strip, extends up to the insole and is sewn to it, is directly glued to the protective lining. However, also with such prior footwear, a very small amount of water seeps through the upper and may stagnate in the space between the lining and the upper.

It is therefore an object of the present invention to provide a waterproof footwear article which does not have the said drawbacks. Said object is achieved by an article of footwear and a process for its manufacture, the main features of which are defined in claims 1 and 10, respectively, while the other features are defined in the subsequent claims.

Thanks to the semipermeable membrane lining the inside of the upper and to the waterproof strip connecting it to the insole, the footwear according to the invention is perfectly waterproof not only over the entire upper surface, but also at its lower edge.

Furthermore, the footwear according to the invention does not require the use of a protective lining, which can be sewn in any way to the insole, if necessary, without any risk of water seepage.

According to a particularly advantageous aspect of the invention, the semipermeable membrane is connected to the upper by means of a gluing means, so that it does not prevent the passage of water vapor.

The waterproof strip is preferably provided with a layer of heat-activated glue, like the glue already used in the textile industry, so that the manufacture of the footwear becomes faster, simpler and cheaper with the manufacturing process according to the invention.

Other advantages and features of the article of footwear and the process for manufacturing it according to the invention will become apparent to those skilled in the art from the following detailed and non-limiting description of an embodiment thereof, taken in conjunction with the accompanying drawings, in which fig. 1 shows a partial cross-sectional view of an article of footwear manufactured by the process of manufacturing according to this embodiment.

Referring to the figures, it can be seen that the waterproof shoe according to the present embodiment of the invention comprises a sole 1 made of plastic or rubber material manufactured in a conventional manner, which is connected to an insole 2 and a welt 3 provided on the sole 1. If possible, the welt is preferably made in one piece with the sole and surrounds the lower edges of the upper 4 and the inner lining 5.

According to the invention, the inner surface of the upper 4 is lined with a waterproof or semi-permeable membrane 6, the surface of which facing the upper 4 is preferably provided with a pattern of glue, in particular heat-activated glue, so as to form a thermal lamination through a process as described in WO 00/22948 of PCT application in the name of the same applicant. In this embodiment, the membrane 6 is semipermeable, that is to say suitable for preventing the passage of water but not of water vapour, and preferably comprises a sheet of polyurethane, polytetrafluoroethylene, polyester or other polymeric material, which is non-porous and has a thickness of between 5 μm and 100 μm so as to allow the passage of water vapour by osmosis. One edge of the waterproof strip 7 is suitable for being glued along the inner face of the lower edge of the upper 4, the opposite edge of the waterproof strip being sewn in particular to the insole 2. The width of the adhesive 8 of the waterproof strip 7, which is glued to the membrane 6 of the upper 4, is 6 to 10mm, this seam connecting the waterproof strip 7 to the insole 2 if any of the linings 5 can be sewn to the insole 2 with the same seam. The waterproof tape 7 has a width of 15 to 20mm and is preferably already provided with a layer of heat activated glue so that it can be heat bonded. For tapes that are not inherently waterproof, the glue may also act to waterproof them.

According to the manufacturing process of the invention, a layer of semipermeable membrane 6 is provided inside the upper 4, after which a waterproof tape 7 is glued at its lower edge and sewn to the insole 2 with the lining 5, if necessary. Finally, the insole 2, in connection with the upper 4, is inserted into a mould, into which molten plastic or rubber material is injected. The plastic or rubber is cured in the mould, forming the sole 1 under the insole 2, and forming the welt 3 around the lower edge of the upper 4 and around the waterproof strip 7 comprised between the lower edge of the upper 4 and the insole 2.

It will be apparent to those skilled in the art that modifications and/or additions may be made to the described and illustrated embodiments without departing from the scope of the invention.

Claims (11)

1. Footwear comprising a sole (1) connected to an insole (2) and to a welt (3) surrounding the lower edge of an upper (4), characterized in that the inner surface of the upper (4) is lined with a waterproof or semi-permeable membrane (6) and in that a waterproof strip (7) connected to the insole (2) is glued along the inner lower edge of the upper (4).

2. An article of footwear according to claim 1, characterized in that the welt (3) is made in one piece with the sole (1) of plastic or rubber.

3. Article of footwear according to any one of the preceding claims, characterised in that the membrane (6) is a semipermeable membrane.

4. The article of footwear according to claim 3, characterized in that the membrane (6) comprises a sheet of polymeric material, in particular a non-porous material.

5. Article of footwear according to any one of the preceding claims, in which the membrane (6) is bonded to the upper (4) by means of a glue pattern, in particular a heat-activated glue.

6. Footwear according to any one of the preceding claims, characterised in that the waterproof strip (7) is sewn to the insole (2).

7. The footwear according to claim 6, characterized in that a lining (5) is sewn to the insole (2) with the same seam (9) that connects the waterproof strip (7) to the insole (2).

8. Article of footwear according to any one of the preceding claims, characterised in that the waterproof strip (7) has a width of between 15 and 20mm and the portion (8) which is bonded to the upper (4) has a width of between 7 and 10 mm.

9. Article of footwear according to any one of the preceding claims, characterised in that the waterproof strip (7) is bonded to the upper (4) by means of a layer of heat-activated glue.

10. Process for manufacturing an article of footwear, characterized in that it comprises the following operating steps:

-lining the inside of the upper (4) with a waterproof or semi-permeable membrane (6);

-gluing a waterproof strip (7) on the lower edge of the upper (4) lined with the membrane (6);

-connecting the waterproof strip (7) to an insole (2);

-inserting the insole (2) connected to the upper (4) into a mould in which the sole (1) is formed under the insole (2), while the welt (3) is formed around the lower edge of the upper (4) and around the portion of the waterproof strip (7) between the lower edge of the upper (4) and the insole (2).

11. Process according to claim 10, characterized in that the lining (5) is sewn to the insole (2) together with the waterproof strip (7).