GB2479220A

GB2479220A - Making an article of footwear by injection moulding

Info

Publication number: GB2479220A
Application number: GB1013703A
Authority: GB
Inventors: Michael Thoraval
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-08-16
Filing date: 2010-08-16
Publication date: 2011-10-05
Anticipated expiration: 2030-08-16
Also published as: GB201013703D0; GB2482933A; GB2479220B; WO2012022967A1; GB201105533D0; GB2482933B

Abstract

A method of making an article of footwear (24, fig 4) comprises the steps of applying a matrix material or "sock" 14 to a die 12 , placing the die 12 within a mould 16 , injecting liquid plastics polymer into the mould 16 such that it comes into contact with the matrix material 14, allowing the polymer to set, and removing the resultant article of footwear 24. The matrix material 14 is a breathable material such as nylon which may also have anti-bacterial properties, while the polymer is a compostable or biodegradable plastics material such as a thermoplastic polyurethane. The invention also extends to an article of footwear (24, fig 4) made according to the method, which may be a dance shoe.

Description

INTELLECTUAL

. .... PROPERTY OFFICE Application No. GB 1013703.2 RTM Date:14 December 2010 The following terms are registered trademarks and should be read as such wherever they occur in this document: Crocs Intellectual Property Office is an operating name of the Patent Office www.ipo.gov.uk -1-An improved shoe

Field of the Invention

This invention relates to improved footwear, especially for use by dancers, and a method for making such.

Background to the Invention

Shoes are generally manufactured in several parts which are then attached together. The sole (out-sole, mid-sole and in-sole), upper and other parts may all be separate pieces that require stitching and/or gluing together to form the complete shoe. Often, especially in the case of leather shoes, the processes of leather production and shoe manufacture require the use of hazardous substances, including adhesives, cleaning agents, solvents, dyes, acids, finishes, alkalis, isocyanates, filing agents, mineral salts (including chrome and zirconium) and anti-mould agents. A number of these listed substances have been linked to, inter alia, an increase in the likelihood and severity of cancer, liver, kidney, heart, lung and skin diseases. With current health and safety regulations, it is desirable to employ safer methods of manufacturing shoes.

In the case of dance shoes, especially pointe shoes, the time and skill required to manufacture a pair of shoes, especially the stitching, results in them being relatively expensive. When won by a professional dancer, the shoes may last only one performance. Therefore, there is a need to produce more cost-effective dance shoes.

Once shoes are won out or broken, they are often disposed of in landfill sites or incinerated. Landfill is not desirable for many reasons, including that it increases the risk that toxins may seep into the surrounding soil and/or into the water table, and the smell in the local area surrounding landfill sites. Incineration increases the amount of potentially harmful gases in the environment, particularly the local environment, especially when chemicals or certain materials have been used in the manufacture of the shoe.

Previously footwear has be manufactured using in plastics materials, such as jelly shoes' made from PVC; however, these have had a very plastic' appearance and once the foot becomes sweaty, there's a risk of the wearer damaging an ankle by slipping.

Furthermore, such shoes rarely have much grip.

CrocsTM are a shoe that has a thick base made from one material (closed cell resin foam made from ethylene vinyl acetate) and an upper that may be constructed from the same material. However, they rely upon air holes to allow the foot to breath'. Ethylene vinyl acetate is generally not biodegradable and therefore shoes made with this material are usually disposed of in landfill sites.

Summary of the Invention

Accordingly, the present invention is directed to a method of making an article of footwear comprising the steps of: Applying a matrix material to a die; Placing the die within a mould; Injecting liquid plastics polymer into the mould such that it comes into contact with the matrix material; Allowing the plastics polymer to set; and Removing the resultant article of footwear comprising the matrix material and the polymer from the mould and die.

By injection moulding the article of footwear, the speed with which the footwear is manufactured and the number of different materials, including glue, is reduced. Injection moulding provides a labour-reduced and therefore cost-effective method of producing articles of footwear. A matrix material allows for a separate internal, or foot-facing', material from the external material.

Preferably, the plastics polymer is an elastomer. By using an elastomer, the footwear remains flexible and allows for a more comfortable fit.

Preferably, the matrix material is a breathable material. The term "breathable" is intended to mean that it allows water vapour to pass through the material but is resistant to water droplets. This is useful for footwear as it allows the heat and water vapour from the foot to pass though the material and away from the foot, making the user more comfortable.

It is advantageous that the polymer material is a compostable or biodegradable plastics material. By using such materials, the shoes can be recycled more efficiently, including use as compost. The shoe may be made from a material that fully biodegrades within ninety days.

It is preferably that the matrix material is provided with at least one reinforced section.

By providing the matrix material with a reinforced section, the footwear can be specifically tailored to a purpose. For example, a dancer may require reinforced toes and/or a shank to protect the toes and support the foot. By reinforcing the matrix material, the shoe can be provided with these features without having to incorporate them at a later stage. This makes the process more efficient and reduces labour costs. Alternatively, it may be desirable to reinforce the heel or side sections of the footwear.

Preferably, the reinforced section is the toe area. The toe section is important to be reinforced in pointe shoes. The article of footwear may be used in hospitals where staff require protection from falling needles or scalpels, or for use on building sites where toe protection is essential.

In one preferred embodiment, the article of footwear is a dance shoe. Dance shoes manufactured according to the present invention can be more durable than those made by traditional methods. Furthermore, by moulding the shoe according to this method, the cost of manufacture can be reduced, making dance shoes more affordable thereby reducing the risk of injury from dancing on broken or worn shoes.

The present invention extends to an article of footwear comprising an internal portion and an external portion, the external portion comprising at least a sole and an upper, wherein the external portion is integrally moulded from at least one material. By moulding the sole and the upper from the same material at the same time, the footwear can be produced using significantly less labour and reduces the risk of those manufacturing the footwear coming into contact with potentially hazardous materials during the process.

The mould may have more than one injection point and a plurality of materials may be injected into the mould simultaneously. The resulting shoe comprises different materials, and therefore different properties, in different sections of the external portion. The shoe may be moulded from multiple layers of polymer being injected during the process of manufacture and the liquid layers bonding to form an integral external portion.

Preferably, the external material is a plastics material. Various plastics materials may be used that can provide sufficient flexibility and stretch for a user to be able to wear the footwear comfortably. Plastics that resemble leather might be used in order to make the footwear appear to be made from leather.

It is advantageous that the internal portion comprises a fabric material. The internal portion, or matrix material, may be in the form of a sock' that binds to the external material and provides a comfortable lining to the footwear.

In one embodiment of the present invention, the material of the external portion is Apilon 52®. Apilon 52® is a thermoplastic polyurethane (TPU) produced by A.P.I. Applicazioni Plastiche Industriali SpA. Other materials that are suitable for injection moulding may also be used, such as natural and synthetic polymers.

In an advantageous construction, the internal material is breathable and/or has anti-bacterial properties. By making the material of the internal portion breathable, the footwear may be more comfortable for the user to wear. The anti-bacterial properties may be inherent to the choice of material used for the internal portion, or the internal portion may have been treated with an anti-bacterial agent.

It is preferably that at least one section is reinforced, and, in a preferred construction, it is advantageous that the reinforced section is the toe portion. Alternatively, the reinforced section may be the heel section or the sides of the shoe, or a combination of reinforced sections, for example the heel and the toe. By providing reinforced sections, the article of footwear can be tailored to a specific task, for instance protecting the toes or heel of the wearer. It may be advantageous for a dance show to have at least a reinforced toe section to protect the dancer's toes when en pointe'.

Brief Description of the Drawings

An embodiment of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional diagram showing one step in the method of manufacturing footwear according to the present invention; Figure 2 is a cross-sectional diagram of a subsequent step to that of Figure 1; Figure 3 is a cross-sectional diagram of a subsequent step to that of Figure 2; and Figure 4 is a view of a footwear according to the present invention.

Detailed Description of Exemplary Embodiments

Figures 1 to 4 show apparatus 10 for, and steps in the process of, manufacturing a shoe according to the present invention.

Lower leg-shaped die 12 comprises two pieces 12a and 12b; front part of the die 12a being the shin (anterior lower leg) portion of a leg and toe portion of a foot, and rear part of the die 12b being the calf (posterior lower leg) portion of the leg and heel portion of the foot. The two pieces are of the die 12a and 12b and connected together such that they do not move relative to one another.

A matrix material, or sock', 14 is positioned on the die 12 and secured in place so that it cannot move relative to the die 12.

As shown in Figure 2, the assembled die 12 and sock 14 are positioned in a two-piece injection mould 16; the mould 16 comprising an upper part 16a which holds the upper, or leg and a lower part 16b. A gap 18 is present between the sock 14 and the mould 16, which corresponds to the shape of the shoe required. The upper part of the die 12 is hermetically sealed within the upper part of the mould 1 6a to prevent any gaps between the mould 16a and the die 12, which may be detrimental to the overall shape of the shoe.

Lower part of the mould 16b is provided with an inlet 20, allowing fluid communication between the gap 18 around the sock 14 and outside of the mould.

Once the die 12 is positioned within the mould 16 and the mould 16 is connected in place on an injection moulding assembly (not shown), liquid polymer is injected through the inlet 20 of the mould 16. The liquid polymer fills the gap 18 and binds to the sock 14.

The sock 14 is made from a material that is non-permeable to the liquid polymer but to which the polymer binds.

Once the liquid polymer 22 has set, the mould 16 is then opened and the rear part of the die 12b is disconnected from the front part of the die 12a and removed. The resulting shoe 24, comprising the polymer layer 22 (external portion) and the sock 14 (internal portion) can then be removed from the front part of the die 1 2a. The use of a two piece die 12 allows for the shoe 24 to be removed relatively easily.

The gap 18 can be varied to increase the dimensions of the shoe, for example, if the sole is required to be thicker on a particular shoe, the size of the gap between the lower part of the mould 16b and the sock 14 is increased, Likewise, if the toe portion is required to be thicker than the rest of the shoe, the size of the gap between the sock 14 and the upper part of the mould 16a is increased accordingly. This allows more liquid polymer to be injected into the required region.

The sock 14 may be provided with reinforced sections to proved, for example for hardened toe sections. When making pointe shoes according to the present invention, the sock 14 may comprise a box section (hard enclosure to encase and support the dancer's toes) and a shank (rigid material that provides support to the arch of the en pointe foot), so that these features are integral to the shoe. Alternatively, the box and/or the shank may be added after the shoe 22 has been made.

The sock may be constructed from nylon 6,6, such as meryl® (TM of Nylstar S.A., Spain), which has a thin weave, is non-permeable to liquid plastics materials, breathable and can be produced with or without a seam, therefore making the resulting shoe more

comfortable.

The liquid polymer may be polyurethane (PU), polyester-based thermoplastic polyurethane (Polyester-based TPU), such as Apilon 52®, or a mixture of PVC and PU, which produces a synthetic leather style of material.

Numerous other variations and modifications to the illustrated construction may occur to the reader familiar with the art without taking the device outside the scope of the present invention. For example, other polymers may be suitable for use in the present invention that have not been listed. Alternative, the internal portion, or sock, may comprise other forms of nylon or natural materials, such as cotton.

Claims

Claims 1. A method of making an article of footwear comprising the steps of: Applying a matrix material to a die; Placing the die within a mould; Injecting liquid plastics polymer into the mould such that it comes into contact with the matrix material; Allowing the polymer to set; and Removing the resultant article of footwear comprising the matrix material and the polymer from the mould and die.
2. A method according to claim 1, wherein the matrix material is a breathable material.
3. A method according to claim 1 or claim 2, wherein the polymer material is a compostable or biodegradable plastics material.
4. A method according to claim any preceding claim, wherein the matrix material is provided with at least one reinforced section.
5. A method according to claim 4, wherein the reinforced section is the toe area.
6. A method according to any preceding claim, wherein the article of footwear is a dance shoe.
7. An article of footwear comprising an internal portion and an external portion, the external portion comprising at least a sole and an upper, wherein the external portion is integrally moulded from at least one material.
8. An article of footwear according to claim 7, wherein the external material is a plastics material.
9. An article of footwear, wherein the internal portion comprises a fabric material.
10. An article of footwear according to claim 8 or claim 9, wherein the material of the external portion is Apilon 52®.
11. An article of footwear according to any one of claims 7 to 10, wherein the internal material is breathable and/or has anti-bacterial properties.
12. An article of footwear according to any one of claims 7 to 11, wherein at least one section is reinforced.
13. An article of footwear according to claim 12, wherein the reinforced section is the toe portion.
14. An article of footwear substantially as described herein with reference to and/or as illustrated in any appropriate combination of the accompanying text and/or drawings.
15. A method of making an article of footwear substantially as described herein with reference to and/or as illustrated in any appropriate combination of the accompanying text and/or drawings.Amendments to the claims have been filed as follows Claims 1. A method of making an article of footwear comprising the steps of: Applying a breathable matrix material to a die; Placing the die within a mould; Injecting liquid plastics polymer into the mould through a plurality of inlets such that it comes into contact with the matrix material and forms multiple layers of polymer; Allowing the polymer to set; and Removing the resultant article of footwear comprising the matrix material and the polymer from the mould and die.2. A method according to claim 1, wherein the matrix material is provided with at least one reinforced section.3. A method according to claim 2, wherein the reinforced section is the toe area.4. A method according to any preceding claim, wherein the article of footwear is a dance shoe.5. An article of footwear made in accordance to the method of any one of claims 1 to 4. $ * eS* ....S * ** * * * *5** *1**S *...II..... * p