NON-SLIP SOLE

Abstract

Shoe sole (1) comprising an outsole (2), an insole (4) and a midsole (3), extending between the insole (4) and the outsole (2), the outsole (2) being made of an elastomer material comprising a plurality of cavities (5) filled with cavity-filling particles (6) which are in the solid state at ambient temperature.

Claims

1.-9. (canceled)

10. A shoe sole comprising: an outsole; an insole; and a midsole, extending between the insole and the outsole, wherein the outsole is made of an elastomer material comprising a plurality of cavities filled with cavity-filling particles which are in the solid-state at ambient temperature, wherein a plurality of open cavities form micro-reliefs distributed over an external surface of the outsole when new, and wherein new open cavities are exposed on the external surface of the outsole due to a distribution of filled cavities throughout the outsole and due to wear.

11. The shoe sole according to claim 10, wherein the cavity-filling particles are water-soluble.

12. The shoe sole according to claim 10, wherein the cavity-filling particles are salts.

13. The shoe sole according to claim 10, wherein the cavity-filling particles are selected from the group consisting of chlorates, perchlorates, and sulfates of potassium, ammonium and magnesium.

14. The shoe sole according to claim 13, wherein the cavity-filling particles comprise MgSO.sub.4.

15. The shoe sole according to claim 14, wherein the cavity-filling particles comprise anhydrous magnesium sulfate.

16. The shoe sole according to claim 10, wherein a mean diameter of the cavity-filling particles is between 0.01 mm and 1 mm.

17. The shoe sole according to claim 16, wherein the mean diameter of the cavity-filling particles is between 0.01 mm and 0.3 mm.

18. The shoe sole according to claim 17, wherein the mean diameter of the cavity-filling particles is between 0.01 mm and 0.1 mm.

19. The shoe sole according to claim 10, wherein the filled cavities are distributed substantially homogeneously through the elastomer material.

20. The shoe sole according to claim 10, wherein the cavity-filling particles occupy between 15% and 60% of a volume of the outsole.

21. The shoe sole according to claim 10, wherein the cavity-filling particles occupy between 25% and 35% of a volume of the outsole.

22. A method for manufacturing a shoe sole according to claim 10, the method comprising: incorporating a plurality of cavity-filling particles into the elastomer material; mixing the plurality of cavity-filling particles and the elastomer material in order to form a substantially uniform mix; and vulcanizing the substantially uniform mix in a mold in a form of an outsole.

Description

DESCRIPTION OF THE FIGURES

[0023] All the embodiment details are given in the following description, supplemented by FIGS. 1 and 2, provided solely by way of non-limiting example, in which:

[0024] FIG. 1 is an enlarged schematic depiction of one example of a portion of an outsole comprising cavities and filling particles;

[0025] FIG. 2 is a schematic depiction of a cross section through one example of a sole of a shoe.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

[0026] What is meant by outsole is the wearing sole, namely that part of the sole that is in contact with the ground.

[0027] What is meant by midsole or middle sole is that part of the sole that extends substantially under the entire foot, against the outsole, and between the latter and the insole or inner sole.

[0028] What is meant by insole or inner sole is that part of the sole in contact with the foot and underneath which the midsole and the outsole successively extend.

[0029] FIG. 2 illustrates one example of a shoe sole 1 according to the invention. This sole comprises an outsole 2, an insole 4 and a midsole 3 extending between the insole 4 and the outsole 2. FIG. 1 schematically illustrates an enlargement of an elevation of an outsole alone.

[0030] A plurality of filling particles 6 occupy part of the volume of the sole. At ambient temperature, these particles are in the solid state. Each one of the cavities is generally occupied by a single particle. Occasionally, several particles may occupy the one same cavity. The particles are distributed substantially uniformly through the body of the sole. The filling particles 6 occupy between 15% and 60%, and more preferably between 25% and 35%, of the volume of the outsole.

[0031] An unworn sole comprises a plurality of cavities. Those which are at the external surface 8 of the sole give rise to micro-reliefs, increasing the coefficient of friction of the sole. The edge corners produced by the open cavities brought to light at the surface of the sole contribute to increasing the coefficient of friction of the sole.

[0032] As the sole gradually wears, the cavities in reserve within the outsole progressively come to light. New micro-reliefs thus regularly appear, affording a high level of grip. Thus, despite wear, the advantageous properties of the sole are maintained without degradation in performance until such point as all of the cavities in reserve have been used up.

[0033] According to a first embodiment of the invention, the cavity 5 filling particles 6 are water-soluble. Thus, as the sole progressively wears, new cavities gradually come to light. The particles are then brought into contact with the environment. As soon as the sole encounters water or moisture, the particles are removed by dissolving.

[0034] According to a second embodiment, the particles are not necessarily water-soluble. They are then removed by a mechanical effect. The particles newly released, during phases of contact and friction with the ground, are ejected. Even if certain particles remain attached for longer, as the sole around them wears away, the retention effect lessens and the particles then leave the remaining cavity portions.

[0035] These two embodiments, which are advantageously combined, afford a self-regenerating effect, progressively bringing new cavities to light as the particles are released. This design makes it possible to ensure the durability of the grip properties associated with the cavities.

[0036] When released, the particles are removed from the cavities either by dissolving in a wet environment and/or by being torn out as a result of the friction of the sole against the ground. The micro-reliefs thus created may then come fully into contact with the ground. Each cavity then contributes to increasing the coefficient of friction. The high density of cavities brought to light at the surface of the sole contributes to producing a sole that exhibits particularly good grip.

[0037] Salts, preferably water-soluble salts, may be used to make the filling particles 6. Use is made, for example, of salts such as chlorates (NaCl) or perchlorates, or sulfates of potassium, ammonium or magnesium, particularly MgSO4 and more preferably anhydrous magnesium sulfate.

[0038] The mean diameter of the particles 6 is comprised between 0.01 mm and 1 mm and more preferably between 0.01 mm and 0.3 mm, and more preferably still, between 0.01 mm and 0.1 mm.

[0039] The invention also provides a method for manufacturing an outsole of a shoe as described in the preceding paragraphs.

[0040] One of the key phases of the method regards the incorporation into the raw elastomer compound of a plurality of filling particles 6. The elastomer material with the added particles are mixed in order to form a substantially uniform hybrid material.

[0041] The mixture obtained is then placed in a sole-shaped mould where it will be vulcanized. The vulcanizing temperatures and times are substantially the same as for a conventional sole.

[0042] The filling particles added to the elastomer material each occupy a volume which, during the vulcanizing phase, makes it possible to generate micro-cavities. These micro-cavities are distributed through the outsole. The presence of the particles makes it possible to form cavities without the need to use chemical additives that generate bubbles during the vulcanizing phase.

REFERENCE NUMERALS EMPLOYED IN THE FIGURES

[0043] 1 Sole [0044] 2 Outsole [0045] 3 Midsole [0046] 4 Insole [0047] 5 Cavities [0048] 6 Particles [0049] 7 Open cavities [0050] 8 External surface of the outsole [0051] 9 Heel [0052] 10 Region of the upper