ANTISOILING IMPROVEMENTS TO OUTSOLES

HELD OF INVENTION

This invention relates to shoe outsoles, for sport and street wear, which exhibit a resistance to the adherence of foreign material.

BACKGROUND DESCRIPTION

A problem with sports shoes in particular is that foreign material, such as dirt and grass, adhere to the outsole. The accumulated effects of this build-up include increased weight, and decreased traction and performance. This is particularly undesirable for players in competition games, though still is a significant problem during casual games or practice. Any player who has spent countless hours cleaning soccer or rugby boots will appreciate any improvement which will reduce cleaning time, or the need for extensive cleaning.

While this represents a significant problem for players of ball sports (e.g. soccer and rugby, etc.) the problem extends to other areas. For instance, golf is another sport where plant material and dirt adhering to shoes is a problem. This can be a particular problem in transmitting weeds between different courses. Tramping and hiking boots can also suffer an accumulated build-up of dirt and foreign material, increasing weight, reducing traction, and distributing plant and soil flora and fauna between different environments.

Biosecurity measures during international travel often target shoes which have been used for hiking, visiting farms, golfing, ball sports etc. Any modifications which improve an outsole's resistance to accumulating soil and plant matter will be of assistance in preparing shoes for international travel.

Other similar problems appear in farming, and in farm boots (including gumboots and Wellington boots). Farm boots in wet weather tend to accumulate mud, and become very heavy and slippery underfoot. Farm boots also stand in animal dung and other microbiologically active material. Reducing transmission from one area to another can

be of great significance. Reducing the amount of mud walked into the farm vehicle would be widely welcomed as well.

As can be seen, there is a problem in a wide range of fields where undesirable material is spread or transmitted from one area to another by being carried on the soles of shoes. Accordingly there is a need for an effective solution to such problems, such as an outsole which is resistant to the adherence of foreign material.

In the prior art, United States (US) patent US2001037876 describes an evaporator having a heatable heat exchange surface, which has a self-cleaning micro-structured surface with elevations and depressions. In addition US patent US2004081764 discloses an antisoiling hard coated film comprising a substantially transparent substrate, a hard coat layer comprising inorganic oxide particles dispersed in a binder matrix, and an antisoiling layer comprising a perfluoropolyether.

Alternative attempts at achieving this effect on shoe outsoles are cited in Adidas patents DE3521141 and JP8252102. These patents both suggest a mechanical means for achieving this effect.

Ideally the industry requires an effective technique for reducing the adherence of foreign material on shoe outsoles, and which is ideally relatively easy to implement. It is therefore an object of the present invention to provide an improved outsole whose outer surface exhibits a resistance to the adherence of soil or plant matter likely to be encountered during normal use of a shoe.

At the very least, it is an object of the present invention to provide the public with a useful choice.

Aspects of the present invention will be described by way of example only and with reference to the ensuing description.

GENERAL DESCRIPTION OF THE INVENTION

According to one aspect of the present invention there is provided a shoe outsole or outer, at least a portion of the outer surface of comprising a modified surface resisting the adherence of foreign material, said surface having a plurality of elevated portions configured to resist the adherence of foreign matter such as soil, said elevated portions being in the range of from 5 to 200 microns inclusive.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which said elevated portions are in the range of from 5 to 100 microns inclusive.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the average height of said elevated portions are in the range of from 5 to 100 microns inclusive.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the distances between said elevations are in the range of from 5 to 200 microns inclusive.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the nodules are distributed substantially evenly over the modified surface.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the elevated portions comprise ridges separated by valleys.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the elevated portions comprise nodules.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the elevated portions comprise nodules upon nodules.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which nodules are distributed in patterns on the modified surface.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the nodules are distributed to resemble ridges on the modified surface.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the elevated portions comprise one or more of: nodules, plateaus, ridges, or other features.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which non-elevated portions comprise one or more of: valleys, channels, depressions, grooves, or lowered features (relative to the elevated portions).

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the outsole, or a portion thereof, is formed of an acrylic resin, polyurethane resin, cross-linkable resin, or self cross-linking resin.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the outsole, or a portion thereof, is formed of a resin incorporating one or more adherence modifying components.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the resin includes a cross-linking agent.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the modified surface comprising elevations is moulded into the surface of the outsole.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the resin is a thermoplastic material and the modified surface is thermoformed into the outsole.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the resin comprises a cross-linkable resin, a self cross-linking resin, or a compatible film-forming binders.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which there is provided a coating on the modified surface, said coating comprising a resin into which is incorporated at least one adherence modifying component, and said coating either allowing for preservation of said elevated portions on the outer surface or allowing for the presence of said elevations to be formed therein.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which an adherence modifying component comprises a member of the group comprising: fluorocarbons, silicones, siloxanes, and polysiloxanes, modified polyacrylates, modified polysiloxanes, and acrylates.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which an adherence modifying component comprises a particulate material, the particulate material being of a member of the group comprising: compounds based on PTFE, polyethylene, polypropylene, and hydrophobic fumed silica.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which an adherence modifying component

comprises a particulate material, the particulate material being of a member of the group comprising: functionally modified PTFE compounds , functionally modified polyethylenes, functionally modified polypropylenes, and hydroxy functional PTFE.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the proportion of adherence modifying component(s) present is based on a loading range of 0.5 to 20% (inclusive) by weight.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the proportion of adherence modifying component(s) present is based on a loading range of 5 to 15% (inclusive) by weight.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which an adherence modifying component when incorporated into said resin provides a low surface energy, which is below 50 dynes/cm.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which an adherence modifying component when incorporated into said resin provides a low surface energy, which is below 35 dynes/cm.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which a resin with adherence modifying component is present as a coating on the outsole.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the resin with adherence modifying component(s) is applied as a coating to an outsole by a method comprising: spraying, dipping, plasma coating, corona discharge, brushing, or rolling.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the outsole to which the coating is applied is of a TPU (thermoplastic polyurethane).

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the outsole includes a coating including a particulate material, in which a said particulate material has an average particle diameter within the range of 0.001 nanometres to 100 microns inclusive

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the particulate material contributes to the presence of said elevations.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the modified surface is etched into the outsole surface.

According to another aspect of the present invention there is provided a shoe outsole or outer substantially as described above in which the etching is by laser etching. According to a further aspect of the present invention there is provided a shoe bearing an outsole or outer substantially as described above.

The present invention relates a soil-resistant and/or self-cleaning outsole for use on shoes. The outsole may be synthetic, of natural products, or a mixture. It is intended that the present invention can be used on a variety of shoes, comprising (for instance) but not restricted to: soccer boots, rugby boots, boots and shoes for ball sports, golf shoes, tramping and hiking shoes and boots, walking shoes, running shoes, street shoes, gumboots, farm boots, safety boots and shoes, shoes and boots for in clean areas (e.g. food processing, dairy and meat industries, etc.), and shoes for use in biohazard areas. For simplicity of description however, the remaining specification will refer primarily to sports shoes such as soccer boots. It is envisaged that application to other shoes and

boots will be readily apparent to the skilled reader in light of the description given herein.

Improvements according to the present invention can be made according to techniques mechanically modifying the outer surface of an outsole or forming elevations into the surface of an outsole (either during its manufacture, or as a post-forming technique). Further modifications may be made to further enhance performance

The applicant has investigated various techniques for producing soiling resistant surfaces, and particularly techniques which can be likened to that used by the lotus leaf in nature. The term 'lotus-effect' refers to the self-cleaning properties of lotus leaves. When rainwater dropped to the hydrophobic surface of the leaves of a lotus, it forms into water beads due to the effect of surface tension, i.e., the contact angle between the surface of the leaves of the lotus and water will be over 140[deg.], and the water beads will roll away from the leaves when shaking the leaves. Further, rolling water beads carry dust from the surface of the leaves. Therefore, the surface of the leaves is maintained clean and dry after a heavy rain. The chemical structure of the wax crystal is hydrophobic. When water contacts the surface of a lotus leaf, it forms into water beads due to the effect of surface tension. Due to the effect of the fine protruding epidermal cell structure, the contact area between water and the surface of the leaf is minimized and the contact angle between water and the surface of the leaf is maximized, enhancing the effect of hydrophobicity, and lowering the adhesion power of solid matter to the surface of the leaf. The nanometered fine structure also plays an important role in self-cleaning. However, rolling water beads on the hydrophobic smooth surfaces of other plants or man-made products cannot cause water beads to carry solid matter from the surfaces. In contrast, lotus leaves become clean and fresh when washed by a heavy rain.

Physical surface modification of the outsole: In the present invention the surface of the outsole is initially formed to incorporate a surface structure comprising an artificial surface structure of elevated portions. A number of different profiles may be adopted including rows of ridge like structures

separated by valleys. In an alternative structure, a plurality of elevated nodules are provided on the surface. Another option has smaller nodules placed on larger nodules. The tops of the nodules may be rounded, or plateaued/flattened. Nodules may be randomly positioned across a surface or arranged in patterns. These patterns may be regular or irregular, or complex patterns which may result from simpler patterns overlying each other. In one preferred arrangement, nodules are arranged roughly to form ridge like patterns, which may appear curved or linear in plan view. A degree of user choice is available here, providing the preferred dimensions are observed - see below.

The modified surface may also be viewed as a surface comprising a plurality of valleys, channels, grooves, or depressions etc. - these being the portions of lower height than the elevated portions. It is irrelevant that the elevated portions may comprise those portions remaining after valleys, or channels etc. have been formed or excavated into the surface from which the modified surface was derived. For simplicity, the elevated portions shall refer to the high points, regardless of how the modified surface was formed.

Whatever configuration is adopted, there should be a high density of raised portions as opposed to depressions (i.e. the non-raised portions). Preferably the distances between the edges of said elevations are in the range of from 5 to 200 microns inclusive. A substantial proportion (i.e. 80% or more of a modified surface) should ideally fall within this criterion. With regard to the average height of the elevations, as opposed to the base of the valleys or depressions, a substantial proportion (again, 80% or more) should be within the range of from 5 to 200 microns, and more ideally 5 to 100 microns, inclusive.

This can be achieved by forming in a specific mould, though post forming techniques such as laser etching, chemical etching, thermo-forming etc. can be considered. The post forming techniques can be used without having to retool existing outsole moulds, or on existing stock or customised footwear.

The material of the outsole may be of any material in which the required surface structure is able to be formed. Currently, commonly used resins for outsole manufacture are envisaged, such as polyurethanes, acrylics, cross-linked resins, etc.

Enhancement options

The resistance to soil adherence may be enhanced by either or both of additionally coating the outsole, or forming the outsole, of a material (such as a resin) in which an adherence modifying component is included.

Surface treatment of the outsole

Surface treatment coatings applied to the present invention typically include adherence modifying components, typically low surface energy materials, these components comprising (but not restricted to) fluorocarbons, silicones, siloxanes, polysiloxanes, and particulates. The particulates may, for instance, be waxes based on PTFE, polyethylene, polypropylene, hydrophobic fumed silica, etc. These particles can range in diameter, are not necessarily spherical, and are preferably within an inclusive size range of 0.001 nanometres to 100 microns (average particle diameter). Furthermore, these particulates can be chemically modified to achieve better compatibility and fixation, and consequently performance, e.g. hydroxy functional PTFE. All the materials quoted provide a low surface energy, which preferably should be below 50 dynes/cm, more optimally below 35 dynes/cm and ultimately below 25 dynes/cm in order to gain the desired effect. Combinations of these products are also a possibility, and within the scope of the present invention. Preferably the coating should not be so thick as to eliminate the elevations of the preferred modified surface - i.e. there should still be elevations within the preferred size limits in the coating, though it is possible that these may be formed into the coating itself.

The surface treatment coating films are typically formed from a film forming resin, comprising cross-linkable (which include self cross-linking varieties) resins (generally of an acrylic or polyurethane nature), or suitable film-forming binders, having the above mentioned modifying components dispersed therein. Such films appear to exhibit

improved anti-soiling characteristics, compared to films from cross-linkable resins that do not contain such materials.

This is particularly advantageous with regard to outsoles surfaces that need to remain free of contamination during use.

It has been found that 0.5 to 20% (inclusive) is a typical loading range of the adherence modifying component (by weight) within the surface treatment coating, with a range of between 5 to 15% (inclusive) being preferred.

A process is provided for making a film-forming composition (for use as a surface treatment coating) containing these materials dispersed in a cross-linkable resin. The process comprises adding the material to a medium (generally a film forming resin), being selected from (but not limited to) the group of film forming resins listed above. Then the material(s) and medium are mixed to form a dispersion, which may require high sheer mixing with the aid of a suitable auxiliary dispersant. Next this coating composition is applied to the outsole surface (e.g. a TPU (Thermoplastic PolyUrethane) resin outsole) by a suitable means of an application method which can control the specific amounts applied. Such equipment may be, but is not limited to, spraying equipment, dipping equipment, plasma coating techniques, corona discharge methods, etc.

As a result the coating is cured, dependent upon the resin type used, which can include (but is not limited to) moisture curing, heat curing, UV curing, and radiation curing, etc. Furthermore the coating can be reinforced (particularly to gain added hydrolytic stability) by the use of self cross-linking resins or the inclusion of cross linkers such as polyaziri dines, polyisocyanates, etc., though may include other cross linking agents. Once cured a durable anti-soiling film is formed upon the surface of the outsole. This achieves a hybridic complex of resin and material, offering permanent self -cleaning, hydrophobic, oleophobic, and anti-adhesive effects.

Additives combined with the outsole raw material:

Outsoles of the present invention can be formed including outsole modifying components, these comprising fluorocarbons, silicones, siloxanes, polysiloxanes, and particulates. The particulates may, for instance, be waxes based on PTFE, polyethylene, polypropylene, hydrophobic fumed silica, etc. These particles can range in diameter, are not necessarily spherical, and are preferably within an inclusive size range of 0.001 nanometres to 100 microns (average particle diameter). Furthermore, these particulates can be chemically modified to achieve better compatibility and fixation, and consequently performance, e.g. hydroxy functional PTFE. All the materials quoted provide a low surface energy, which preferably should be below 50 dynes, more optimally below 35 dyes and ultimately below 25 dynes in order to gain the necessary effect. Combinations of these products are also a possibility.

An outsole modifying component is mixed with a TPU (Thermoplastic PolyUrethane) resin before the moulding process begins. Once the TPU mix is injected into the mould, it will form an equilibrated structure throughout, with substantially permanent anti- soiling properties contained throughout the outsole, and where the effect is constantly replenished with wear. These improved outsoles exhibit improved anti-soiling characteristics, compared to outsoles that do not contain such materials.

This has the potential to be particularly advantageous with regard to outsoles surfaces that need to remain free of contamination during use.

DESCRIPTION OF DRAWINGS With reference to the drawings, and by way of example only, preferred embodiments of the present invention will now be described.

Figure 1: is a perspective view of one preferred embodiment of the present invention,

Figure 2: is a side diagrammatic view of another embodiment of the invention, and

Figure 3: is a side diagrammatic view of yet another embodiment of the invention.

PREFERRED EMBODIMENTS OFTHE INVENTION Example 1

A mould is used for forming the outsole, or at least that portion of its outer surface which is to offer the features of the present invention. The mould is specifically designed to micro replicate a surface such as illustrated in figure 1. TPU (thermoplastic polyurethane) is injected and cast so that the surface of the outsole possesses the characteristic surface structure shown in one of the figures. Other plastics, rubbers, or resins may be used as may be commonly used for outsole construction.

In figure 1 can be seen a characteristic nodule 1, raised from a base nodule 2, structure. The nodules are roughly arranged to form parallel curved lines resembling ridges, though a random structure may be adopted. The base nodule shown here is mound-like and rounded, though may take other forms (e.g. a raised ridge like base portion, and raised base portions of other shapes).

In Figure 2 can be seen a plurality of ridges 10 in cross section. The height 'y ' is ideally in the range 5-100 microns inclusive, and peak to peak distance 'x' roughly in the range of 5-200 microns inclusive.

In Figure 3 can be seen an arrangement of nodules 20 which partially obscure a second row of nodules 21 behind. These eclipse other nodules behind. These are single nodules (as opposed to the nodule on nodule arrangement of Figure 1).

Example 2

A cast outsole is modified through laser etching to adopt a surface structure such as shown in figure 1. This process is most suitably performed on the outsole prior to bonding to the shoe upper, but can be completed at a later stage of shoe manufacture. This allows the features of the present invention to be used on materials which may not readily lend themselves to the moulding techniques of example 1 or to modify/customise an existing set of shoes.

Additional Surface treatment of the outsole Example 3

The following formulation is made as a coating to be applied to an outsole such as described in examples 1 or 2: 78% Solvent based polyurethane 10% Solvent based polyisocyanate 10% an acrylate e.g. NLC Additive SS 1 (NLC, UK) 2% Flow Agent

The above mixture may require high speed shear stirring to ensure adequate dispersion. Anti-foaming agent may be required and added as necessary.

The mixture is then applied by a spraying, with the application of from 0.05 to 250 gff ² , though more preferably in the range 7-30 gft ^"2 inclusive. This is then heat cured until properly cured. For the preferred coating range, this may be for 3 minutes at a temperature of 125 ⁰ C, and allowed to cure for a further 48 hours at room temperature before any sort of laboratory testing.

The outsole can then be applied to the upper. In addition the outsole of completed shoes can also be treated in this manner.

Example 4

The following formulation is made as a coating to be applied to an outsole such as described in examples 1 or 2: 78% Solvent based polyurethane 10% Solvent based polyisocyanate

10% Solvent based fluorocarbon e.g. NLC Additive SS3 (NLC, UK) 2% Flow Agent

The above mixture may require high speed shear stirring to ensure adequate dispersion. Anti-foaming agent may be required and added as necessary.

The mixture is then applied by a spraying, with the application of from 0.05 to 250 gff ² , though more preferably in the range 7-30 gft ^'2 inclusive. This is then heat cured until properly cured. For the preferred coating range, this may be for 3 minutes at a temperature of 125 ⁰ C, and allowed to cure for a further 48 hours at room temperature before any sort of laboratory testing.

The outsole can then be applied to the upper. In addition the outsole of completed shoes can also be treated in this manner.

Additives combined with the outsole raw material:

Example 5

The following formulation is made for forming into an outsole such as in example 2:

88% TPU resin INCREASED RESIN AMOUNT

10% Hydrophobic fumed silica e.g. NLC Additive SS2 (NLC, UK) 2% DISPERSING Agent

The mixture is then injected into an outsole mould for thermoforming, as per example 2.

The outsole can then be applied to the upper. This technique offers the potentially realisable added benefit of enhanced durability due to an additional anticoiling effect being locked within the outsole material and constantly offering benefits as the outsole' s surface wears.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the spirit or scope of the present invention as defined in the appended claims.

It should also be understood that the term "comprise" where used herein is not to be considered to be used in a limiting sense. Accordingly, 'comprise' does not represent nor define an exclusive set of items, but includes the possibility of other components and items being added to the list.

This specification is also based on the understanding of the inventor regarding the prior art. The prior art description should not be regarded as being authoritative disclosure on the true state of the prior art but rather as referencing considerations brought to the mind and attention of the inventor when developing this invention.