a new type of shoe

Abstract

Shoe (1) extending longitudinally from a front extremity (2) towards a rear extremity (3) and comprising a sole (4), an upper (5) and an insole (6), said sole (4) comprising an insert (7), a partial cover (8) of the insert (7) and a pad (9) suitable for forming a wear surface of the sole (4), the insert (7) is a molded piece of thermoplastic polyurethane having a density of between one hundred and fifty and three hundred kilograms per cubic meter, the cover (8) cooperates with the insole or the pad to completely conceal the insert (7), the cover has a density greater than the insert (7) and the insert (7) has, at the front quarter (10) of the shoe (1) taken along the front / rear longitudinal direction of the shoe (1), an average thickness less than the average thickness of the insert (7) at the rear quarter (11) of the shoe (1). Figure for the abridged version: Fig. 1

Description

Title of the invention: a new type of shoe

[0001] The present invention relates to a shoe.

[0002] It relates in particular to a shoe developing longitudinally from a so-called front end towards a so-called rear end and comprising a sole, an upper and a mounting insole.

[0003] Consumers are looking for increasingly lightweight shoes. However, this lightness often comes at the cost of a complex manufacturing process. Shoe manufacturers, for their part, are looking for solutions to facilitate the recycling of these shoes and to utilize plastic waste.

[0004] One aim of the present invention is to provide a shoe that combines lightness and ease of recycling.

[0005] To this end, the invention relates to a shoe extending longitudinally from a front end towards a rear end and comprising a sole, an upper and an insole, characterized in that said sole comprises an insert, a partial cover for the insert and a pad adapted to form a wear surface of the sole in contact with the ground, in that the insert is a molded part made of thermoplastic polyurethane having a density of between one hundred and fifty and three hundred kilograms per cubic meter, in that the cover cooperates with the insole or the pad to completely conceal the insert, in that the cover has a density greater than that of the insert and in that the insert has, at the level of the front quarter of the shoe taken along the front / rear longitudinal direction of the shoe,an average thickness less than the average thickness of the insert at the rear quarter of the shoe.

[0006] The presence of an insert reduces the amount of material in the upper, which must possess aesthetic characteristics as well as mechanical resistance and durability, thus limiting the range of usable materials. Making the insert from thermoplastic polyurethane facilitates the recycling of the sole, allows the use of a material that can be sourced from offcuts since this material is not visible from the outside of the shoe, and lightens the shoe by manufacturing the insert in such a way as to give it a very low density. This low density is, in a manner known per se, obtained by the use of a physical and / or chemical expanding agent during the manufacturing of the insert.The insert's shape allows for further optimization of the amount of material needed to make the upper, without compromising the manufacturing quality of the sole or its mechanical resistance.

[0007] According to one embodiment of the invention, the insert has a surface in contact with the pad or the mounting plate. This contact surface allows the insert to be pre-bonded to the pad or the mounting plate with which it has a contact surface before proceeding with the injection molding of the casing.

[0008] According to one embodiment of the invention, the insert comprises, locally within its surface in contact with the sole or insole, at least one channel, the channel or channels extending parallel or transversely to the front / back direction of the shoe, the channel or channels being filled with the material constituting the outer layer. The presence of channels allows the outer layer to act, at least locally, as an interface between the insert and the sole or insole to prevent delamination of the insert from the sole or insole with which it is in contact. Ideally, each channel extends parallel to the injection direction of the material constituting the outer layer.

[0009] According to one embodiment of the invention, the channel or at least one of the channels has at least one local enlargement. Again, such an enlargement facilitates the anchoring of the insert to the material constituting the casing.

[0010] According to one embodiment of the invention, the or at least one of the enlargements delimits a circular cavity open towards the pad or the first mounting with which the insert is in contact.

[0011] According to one embodiment of the invention, the channel or at least one of the channels has a minimum width of at least five millimeters.

[0012] According to one embodiment of the invention, the insert has, locally, on its surface in contact with the pad or the mounting insole, an adhesive for bonding the insert to the pad or the mounting insole. The use of adhesive ensures the relative positioning of the insert and the pad or the mounting insole before the casing is formed by injection molding.

[0013] According to one embodiment of the invention, the casing is made of sand-colored thermoset polyurethane.

[0014] According to one embodiment of the invention, the envelope has a density of between one hundred and fifty and three hundred kilograms per cubic meter.

[0015] According to one embodiment of the invention, the outer layer represents at most fifty percent (50%) expressed as a percentage by volume relative to the total volume of the sole. This configuration facilitates the recycling of the sole.

[0016] According to one embodiment of the invention, the skate is a molded part made of polyurethane thermoplastic.

[0017] The invention also relates to a method for manufacturing a shoe, characterized in that, the shoe being of the aforementioned type, the method comprises a step of applying the insert onto the first mounting plate or onto the pad and a step of injecting the envelope into a mold closed by the first mounting plate.

[0018] Preferably, the insert is a part produced by molding in the presence of at least one physical or chemical expanding agent and a supercritical fluid, such as supercritical CO2 (carbon dioxide). Brief description of the drawings

[0019] The invention will be better understood upon reading the following description of exemplary embodiments, with reference to the accompanying drawings in which:

[0020] [Fig-1] represents a schematic view of a shoe according to the invention;

[0021] [Fig.2] represents a schematic view of a sole to illustrate the front quarter and back of the shoe;

[0022] [Fig.3] represents a schematic view of an upper / insole / insert assembly of a shoe according to the invention;

[0023] [Fig.4] represents a schematic view of a skate / insert assembly of a shoe according to the invention;

[0024] [Fig.5] represents a schematic top view of an insert;

[0025] [Fig.6] represents a schematic side view partially in section of an insert;

[0026] [Fig.7] represents a schematic cross-sectional view of an insert.

[0027] As mentioned above, the invention relates to a shoe 1 of the type of that represented schematically in [Fig. 1]. This shoe 1 comprises a sole 4, an upper 5 and a mounting insole 6. This shoe develops from a front end 2, also called the toe of the shoe 1, towards the rear end 3, which forms the heel of the shoe 1.

[0028] The upper 5 has a first opening through which the foot is inserted into the shoe. The insole 6 is attached to the upper 5, generally by a Strobel stitch (registered trademark). This insole 6 closes a second opening in the upper 5 in a manner known per se. The sole 4 is attached to the upper 5 and the insole 6. This sole 4 comprises an insert 7, a partial cover 8 for the insert, and a pad 9 adapted to form a wear surface for the sole 4 in contact with the ground. Generally, the pad 9 is a molded part made of thermoplastic polyurethane. This pad 9 is therefore prefabricated. Similarly, the insert 7 is a prefabricated part. This insert 7 is a molded part made of thermoplastic polyurethane having a density of between one hundred and fifty and three hundred kilograms per cubic meter.To achieve such a density, insert 7 is a part incorporating at least one physical or chemical expanding agent. An example of manufacturing such a low-density expanded article is described in patent EP-3027,377. Ideally, the process consists of combining, in an extruder, . A molten polymer consisting of thermoplastic polyurethane, a physical or chemical blowing agent other than a supercritical fluid, and a supercritical fluid such as CO2, are used to mold the mixture by injection into a mold comprising a porous tool. Physical or chemical blowing agents function as gas sources by undergoing a phase change. Suitable physical blowing agents can be chosen from the group consisting of aliphatic hydrocarbons and their chloro- and fluoro-derived compounds. Chemical blowing agents produce a gas via a chemical reaction. These compounds can be formed from a mixture of carbonate and acid that generates CO2. Again, such agents will not be described in further detail as they are well known to those versed in this art.

[0029] To facilitate the manufacture of the shoe 1 and limit the amount of material constituting the upper 8, the insert 7 has, at the front quarter 10 of the shoe 1 taken along the front-to-back longitudinal direction of the shoe 1, an average thickness less than the average thickness of the insert 7 at the rear quarter 11 of the shoe 1. This variable thickness of the insert 7 is particularly visible in [Fig. 6]. The parts of the insert located at the front and rear quarters of the shoe 1, which have different thicknesses, are represented by hatching in [Fig. 2].

[0030] To define the front quarter and rear quarter of the shoe 1, it suffices to divide the shoe 4 transversely into four parts along the longitudinal axis of the shoe, that is, the axis which connects the front and rear ends of the shoe 1, as illustrated in [Fig. 2]. The front quarter 10 corresponds to the part of the shoe located between the toe forming the front end 2 of the shoe and the line, transverse to the longitudinal axis of the shoe, offset from the toe by one-quarter of the shoe's length, the shoe's length corresponding to the distance between the front and rear ends of the shoe 4. The rear quarter 11 corresponds to the part of the shoe located between the rear edge of the heel forming the rear end 3 of the shoe and the line, transverse to the longitudinal axis of the shoe, offset from this rear end by one-quarter of the shoe's length.

[0031] The insert 7 has a surface in contact with the pad 9 or the first mounting 6. This surface is represented in 121 when it corresponds to the surface in contact with the pad 9 or in 122 when it corresponds to the surface in contact with the first mounting 6.

[0032] In the example of [Fig.3], the insert 7 has a surface 122 in contact with the mounting first 6. Generally, this insert 7 is pre-fixed to the mounting first 6 before the injection molding of the envelope 8 which completely masks from view, by cooperating with the mounting first 6, this insert 7.

[0033] For this purpose, the insert 7 has locally, at the level of its surface 122 in contact with the first mounting 6, a bonding adhesive 15 of the insert 7 to the first mounting 6. This adhesive 15 is preferably a hot melt adhesive of the polyethylene or polyamide type.

[0034] To improve this adhesion between the mounting insole 6 and the insert 7, the insert 7 includes, locally, in its surface 122 in contact with the mounting insole 6, at least one channel 13. The channel or channels 13 extend parallel or transversely to the front-to-back direction of the shoe 1. The channel or channels 13 are filled with the material constituting the outer shell 8. Such channels 13 are visible in [Fig. 5], where there are two channels 13. They extend parallel to the front-to-back direction of the shoe 2, which corresponds to the injection direction of the material constituting the outer shell 8. Indeed, the outer shell 8 is injected here from the part intended to form the rear end 3 of the shoe.

[0035] The design of the insert 7 with a lesser thickness at the front quarter 10 of the shoe 1 facilitates the finishing of the material constituting the cover 8 in the mold during the manufacturing by injection of the cover 8.

[0036] To further improve the connection between the casing 8 and the mounting first 6, one or more of the channels 13, ideally each channel 13, has at least one local enlargement 14. Figure 5 illustrates these enlargements 14, each of which defines a circular cavity open towards the mounting first 6 with which the insert 7 is in contact. Ideally, each channel 13 has a minimum width of at least five millimeters (5 mm).

[0037] In the example shown in Figures 5 to 7, each channel 13 has, excluding the enlargements, a width of 5 millimeters and 13 millimeters at the enlargements and a depth of 4 to 5 millimeters. There are three enlargements per channel.

[0038] Figure 4 illustrates the case where the insert 7 has a surface 121 in contact with The skate 9. The manufacturing principle is the same, namely that the insert 7 has, locally on its surface 121 in contact with the skate 9, an adhesive 15 for bonding the insert 7 to the skate 9 and includes, locally on its surface 121 in contact with the skate 9, at least one channel 13. The channel or channels 13 extend, with respect to the front-to-back direction of the shoe 1, parallel or transverse to said direction. The channel or channels 13 are filled with the material constituting the outer shell 8. Each channel has, locally, at least one enlargement 14, this enlargement 14 delimiting a circular cavity open towards the skate 9 with which the insert 7 is in contact. The dimensions of the channels may be similar to those described above.

[0039] This configuration allows, thanks to the channels, good diffusion of the material constituting the envelope, at the interface of the link between the insert and the first mounting or the pad to avoid the presence of air gaps and ensure effective adhesion with a reduced, or even zero, risk of delamination.

[0040] The casing 8 is an injection-molded piece made of thermosetting polyurethane. This casing 8 has a higher density than the insert 7. Generally, the casing 8 has a density between 450 and 500 kilograms per cubic meter (450 and 500 kg / m³). The casing 8 represents at most 50%, expressed as a percentage by volume, of the total volume of the sole 4 to facilitate the recycling of the sole 4.

[0041] In practice, the upper 8 is manufactured as follows. The upper and the insole, assembled to the upper, are positioned on a last. The insert 7 is glued to the insole or the sole 9. An open mold is applied over the upper / insole assembly and closed by the insole. This mold defines a cavity that houses the sole and the insert. The cavity is filled with the upper material, which is injected into the mold cavity. The upper material flows into the cavity so that, in conjunction with the sole or the insole, it completely covers the insert. Once the injected material has hardened, the mold is opened and the finished shoe can be removed from the last.Such a shoe 1 is characterized by its lightness, its ease of recycling and the possibility of using a reduced amount of material for the making of the upper without compromising the comfort or the aesthetics of the shoe 1.

[0042]

Claims

Demands

1. Shoe (1) extending longitudinally from a front end (2) towards a rear end (3) and comprising a sole (4), an upper (5) and an insole (6), characterized in that said sole (4) comprises an insert (7), a partial cover (8) for the insert (7) and a pad (9) adapted to form a wear surface for the sole (4) in contact with the ground, in that the insert (7) is a molded piece of thermoplastic polyurethane having a density of between one hundred and fifty and three hundred kilograms per cubic meter, in that the cover (8) cooperates with the insole or the pad to completely conceal the insert (7), in that the cover has a density greater than the insert (7) and in that the insert (7) has, at the front quarter (10) of the shoe (1) taken along the front / rear longitudinal direction of the shoe (1),an average thickness less than the average thickness of the insert (7) at the rear quarter (11) of the shoe (1).

2. Shoe (1) according to claim 1, characterized in that the insert (7) has a surface (121; 122) in contact with the skate (9) or the mounting insole (6).

3. Shoe (1) according to claim 2, characterized in that the insert (7) locally comprises in its surface (121; 122) in contact with the skate (9) or the mounting insole (6) at least one channel (13), the channel or each channel (13) extending with respect to the front / rear direction of the shoe (1) parallel or transverse to said direction, the channel or each channel (13) being filled with the constituent material of the outer shell (8).

4. Shoe (1) according to claim 3, characterized in that the or at least one of the channels (13) locally has at least one enlargement (14).

5. Shoe (1) according to claim 4, characterized in that the or at least one of the enlargements (14) delimits a circular cavity open towards the sole (9) or the first mounting (6) with which the insert (7) is in contact.

6. Shoe (1) according to any one of claims 3 to 5, characterized in that the or at least one of the channels (13) has a minimum width of at least five millimeters.

7. Shoe (1) according to any one of claims 2 to 6, characterized in that the insert (7) has locally, at the level of its surface (121, 122) in contact with the sole (9) or the insole (6), an adhesive (15) for bonding the insert (7) to the sole (9) or to the insole (6).

8. Shoe (1) according to any one of claims 1 to 7, characterized in that the outer shell (8) is made of thermosetting polyurethane.

9. Shoe (1) according to any one of claims 1 to 8, characterized in that the upper (8) has a density of between four hundred and fifty and five hundred kilograms per cubic meter.

10. Shoe (1) according to any one of claims 1 to 9, characterized in that the upper (8) represents at most fifty percent (50%) expressed as a percentage by volume relative to the total volume of the sole (4).

11. Shoe (1) according to any one of claims 1 to 10, characterized in that the sole (9) is a molded part made of thermoplastic polyurethane.

12. Method of manufacturing a shoe (1), characterized in that the shoe (1) conforming to one of claims 1 to 11, the method comprises a step of applying the insert (7) onto the insole (6) or onto the sole (9) and a step of injecting the upper (8) into a mold closed by the insole (6).

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