WO2012075314A1

WO2012075314A1 - Durable insoles for footwear

Info

Publication number: WO2012075314A1
Application number: PCT/US2011/062927
Authority: WO
Inventors: Kim Young-Hwa; Peter Gottschalk
Original assignee: Higher Dimension Materials, Inc.
Priority date: 2010-12-01
Filing date: 2011-12-01
Publication date: 2012-06-07

Abstract

In some aspects, the disclosure relates to a removable insole for footwear comprising a cushioning layer, a woven or nonwoven fabric substrate attached to a top surface of the cushioning layer, and a plurality of non-overlapping, guard plates separated by gaps between directly adjacent guard plates on a surface of the woven or non-woven fabric substrate. The guard plates comprise a cured polymer resin partially penetrating into the surface of the woven fabric substrate to a depth less than a thickness of the woven fabric substrate to provide a mechanical bond between the woven fabric substrate and the guard plates.

Description

DURABLE INSOLES FOR FOOTWEAR

TECHNICAL FIELD

[0001] In some examples, the disclosure relates to removable insoles for footwear with enhanced durability and comfort.

BACKGROUND

[0002] None.

SUMMARY

[0003] In general, the disclosure relates to insoles for use with footwear. In some examples, the insole may include a cushioning layer with a fabric layer attached to a surface of the cushioning layer, e.g., via an adhesive layer. A plurality of polymer guard separated by gaps may be provided on the surface of the fabric layer opposite that of the cushioning layer. In some examples, guard plates may increase the durability of the insole and may allow for air flow within the gaps between adjacent guard plates over the surface of the insole when used with footwear worn by a user.

[0004] In some examples, the disclosure relates to a removable insole comprising a cushioning layer; a woven or nonwoven fabric substrate attached to a top surface of the cushioning layer; and a plurality of non-overlapping, guard plates separated by gaps between directly adjacent guard plates on a surface of the woven or nonwoven fabric substrate, the guard plates comprising a cured polymer resin partially penetrating into the surface of the woven fabric substrate to a depth less than a thickness of the woven fabric substrate to provide a mechanical bond between the woven fabric substrate and the guard plates.

[0005] In another example, the disclosure relates to composite fabric assembly comprising a woven or nonwoven fabric substrate; a plurality of non-overlapping, guard plates separated by gaps between directly adjacent guard plates on a surface of the woven fabric substrate, the guard plates comprising a cured polymer resin partially penetrating into the surface of the woven or nonwoven fabric substrate to a depth less than a thickness of the woven fabric substrate to provide a mechanical bond between the woven fabric substrate and the guard plates; and an adhesive layer attached to a side of the fabric substrate opposite the guard plates, wherein the adhesive layer is configured to adhere to a surface of a removable insole.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 shows a view of an insole including a plurality of guard plates on the top surface.

[0007] FIG. 2 shows a magnified view of the guard plate covered insole where the gaps between the guard plates are more clearly illustrated.

[0008] FIG. 3 shows a cross sectional diagram of an example insole.

DETAILED DESCRIPTION

[0009] In some examples, footwear may contain an insole, or innersole, which is a specifically designed cushioned material on which the foot rests within the footwear. Some insoles are bonded in place as permanent parts of the shoe, such as in dress shoes. Many insoles today are removable so they can be replaced when they degrade or become damaged.

[0010] Removable insoles for footwear may be used for increased user comfort, e.g., by providing additional cushioning for the foot in a shoe or boot. Removal also allows for cleaning and drying of the insole which is important for footwear targeted for outdoor markets. The cushioning materials for such insoles may range from simple foams to multi-material constructions including, for example, of different foam and gel materials. While a wide range of cushioning materials exist, generally the top surface of an insole is a smooth surface which allows easy entry and removal of the foot.

[0011] This disclosure relates to the improvement of the wear properties of the insole and the comfort of the user. For example, an insole may include a printed pattern of protruding hard, rigid guard plates to the top surface of the insole. The guard plates may comprise a cured polymer. The guard plates may also comprise wear enhancing hard particle additives such as: aluminum oxide, silicon oxide, zirconium oxide, and/or metal particles. The guard plates on the top surface of the insole may provide increased wear to the top surface of the insole as a user's foot (sometime covered by a sock) is repeatedly inserted into the footwear. The discrete guard plate pattern may also provide continuous gap areas between the guard plates. In this way, air is allowed to move beneath the bottom of the foot of a user during use, e.g., to provide a cooler and drier environment for the foot.

[0012] FIG. 1 shows a removable insole 100 with separated, discrete guard plates, 102, arranged on the top surface of insole 100 in a pattern. Guard plates 102 are separated by gap areas on the surface of a base fabric substrate to provide a continuous gap region over the entire surface of the insole. Insole 100 may be shaped and sized to be inserted into footwear.

[0013] FIG. 2 shows a magnified view of top surface 200 of insole 100. As shown, discrete guard plates 202 are arranged in a repeating pattern with gap regions around each discrete guard plate providing a multiplicity of air flow paths 203 between the guard plates. As represented by air flow paths 203, air may flow freely between guard plates 202 in a straight line and/or in any zigzag pattern along the gap regions.

[0014] FIG. 3 shows a cross sectional view of an insole 300 with discrete guard plates 302 printed on and partially penetrating 305 a base fabric 308. The base fabric 308 plus guard plate 302 assembly is attached to cushioning material 301 via an adhesive layer 304. Guard plates 302 protrude above the surface of the base fabric 308 by a height 306 and have an overall thickness 307 (penetration depth plus protrusion height). When inserted into footwear as an insole, base fabric 308 and guard plates 308 may form the upper surface that contacts a user's foot when the footwear is worn by the user.

[0015] Cushioning material 301 may be any suitable insole material that provides cushioning for insole 300. In some examples, cushioning material 301 may include polyurethane foam, such as Poron™ available from Rogers Corporation, polyethylene foam, available from Inter-Pac, Qycell and New England Foam, latex foams, and ethylene-vinyl acetate open celled foams.

[0016] Adhesive layer 304 may be formed of any suitable material for adhering (e.g., laminating) base fabric 308 to cushioned insole material 301. In some examples, adhesive layer 304 may include Upaco 2143 urethane adhesive, Upaco 5673, Upaco 5675 and other Upaco series adhesives available from Worthen Industries, Nashua, NH, 301 Waterbase Flexweld available from Imperial Adhesives, Inc of Cincinnati, OH, and # 14-24-1 available from Mid-west.

[0017] In some examples of the disclosure, advanced fabric material for forming top layer (base fabric 308 plus guard plates 302) of insole 300 may include SuperFabric®. SuperFabric® (commercially available from Higher Dimension Materials, Oakdale, MN) may be a family of fabric assemblies with a variety of unique features. In some examples, SuperFabric® may comprise a woven or non- woven base fabric material, e.g., base 308, onto which cured polymer guard plates, e.g., plates 302, have been attached, e.g., due to the partial penetration of the guard plates into the surface of the substrate before being fully cured. Examples of articles including a woven or non- woven base fabric material may include one or more examples described in United States Patent No. 6,962,739, entitled "Supple Penetration Resistant Fabric and Method of Making;" United States Patent No. 7,018,692, entitled "Penetration Resistant Fabric with Multiple Layer Guard Plate Assemblies and Method of Making the Same;" published United States Patent Application No. 2004/0192133, entitled "Abrasion and Heat Resistant Fabrics;" and published United States Patent Application No. 2009/014253, entitled "Supple Penetration Resistant Fabric and Method of Making."

[0018] In some examples, SuperFabric® can be fabricated to resist water penetration, oil and other stains and remain flexible and breathable. SuperFabric® may greatly increases the wear resistance properties of the base fabric as measured by Taber Abrasion testing (ASTM 3884). For example, SuperFabric® fabric assemblies provide increased abrasion resistance, as determined by the number of cycles in the Taber Abrasion test, by factors ranging from 2 to over 12 times.

[0019] Example fabric types for base fabric 308 may include, but are not limited to, woven, non-woven, or knit fabrics having the ability to permit at least partial penetration of uncured resin used to form polymeric guard plates 302 after deposition of the uncured polymer on fabric substrate. Fabric materials include without limitations cotton and cotton-polyester blends and other natural and man- made fabrics having similar properties. In one example, the flexible fabric substrate may include a tightly woven cotton-polyester blend. In such an example, this type of fabric may be used because resin compositions including heat-cured epoxy resins used to form guard plates have been found to seep into and bond well with this substrate fabric.

[0020] As noted above, in some example, guard plates 302 may be arranged to provided contiguous, connected gap regions over the surface of base fabric. Guard plates 302 may range in size and shape, and in overall geometrical arrangement, and guard plates 302 may be identical to one another, or may be made of identical groupings of guard plates 302. Guard plates 302 may be arranged in a regular geometric pattern on surface of base fabric 308. Guard plates 302 may also differ from one another and be arranged in a random pattern on the surface of base material 302. Guard plates 302 may partially penetrate into the base fabric to ensure good adhesion between guard plates 302 and base fabric 308. Guard plate dimensions in the plane parallel to the surface plane of base fabric 308 range from 30 mils to 150 mils. In some examples, guard plates 302 may protrude above the surface of the base fabric 308 to a height 306 ranging from about 5 to 40 mils. Protrusion of guard plate 308 may be less than the largest dimension of guard plate 302 in a plane parallel to the top surface of base fabric 308. Gap widths 303 between adjacent guard plates 302 may range from about 5 mils to 40 mils.

Dimesions outside the exemplary ranges described herein are also contemplated. Without loss of generality, insole 300 may have guard plates 302 with gap widths that are not uniform over the entire insole 300 to allow insole 300 to conform to the curved surfaces often required for footwear insoles. In some cases it may be desirable to include guard plates 302 on the bottom of the insole also. For example, this may improve the wear characteristics of the insole.

[0021] Gap areas 303 between guard plates 302 may be sufficiently narrow to prevent the user's sock and/or foot from filling the gap area 303 between adjacent guard plates 302. In this manner, a permanent air reservoir may be maintained beneath the user's foot above insole 300. Furthermore, since the gap regions between guard plates 302 may be contiguously connected, air may be free to flow along the gap areas during use. The free flowing air may prevent excessive moisture and temperature buildup beneath the foot.

[0022] In some examples, guard plates 302 may be constructed of a variety of composite materials, such as cured epoxies, polyurethanes, hybrid of cured epoxy- polyurethane, etc. composited with wear and strength enhancing materials such as silicon dioxide, aluminum oxide, titanium oxide and other filler materials such as pigments.

[0023] Suitable polymeric compositions for forming guard plates 302 may include epoxy resin(s). In one embodiment, plates 302 may be formed of heat-cured epoxy resin. Another example of an appropriate resin may be ultra-violet (UV) cured acrylate. Depending on the particular application, plates 302 may have a hardness between about 70 and about 100 Shore D, such as, e.g., between about 80 and about 95 Shore D. The hardness of plates 302 may depend on a number of factors including, but not limited to, the polymeric resin composition used to form the plates and/or the process used to cure the polymeric resin composition after being deposited on the surface of base fabric 308. In some embodiments the guard plates may comprise a thermoset epoxy. In some embodiments the guard plates may comprise inorganic filler particles. Thermally cured polymeric materials used for guard plates may be relatively hard and crack-resistant.

[0024] In some example, the polymer resin selected for use to form guard plates 302 may ensure a strong bond between the guard plate and the base fabric 308. In some examples, a suitable polymer resin for construction of guard plates is a one- part heat-curable epoxy resin formulated to (i) provide abrasion resistance, (ii) be screen printable, (iii) be resistant to fracture, (iv) be bondable to the base material, and (v) have good shape definition during printing and curing of the guard plate material. Such resins may be readily formulated to meet these criteria and are available from, for example, Fielco Industries, Inc., Huntingdon Valley, PA, 19006, which has formulated resins that may meet the characteristics set forth in this paragraph and has given them the designations: TR21 and TR84. Other examples of suitable resin formulations are available from Hexion Specialty Chemicals, Columbus, OH 43215. For example, Hexion Starting Formulation 4019 may be a suitable thermosetting heat curable epoxy base resin formulation. In some examples, abrasion resistance provided by guard plates can be increased by adding small particles (e.g., 1 to 100 micrometers) of silica, alumina, silicon carbide, titanium oxide and the like to the resin. [0025] In some embodiments, the use of low-wicking resin compositions to form guard plates 302. In some examples, a low-wicking polymeric resin composition may include one or more of an epoxy resin, phenolic resin, e.g., bakelite, polyester resin, polyurethane resin, polyimide resin, allyl resin, and the like. The polymeric resin may be a polymeric resin that irreversibly cross-links via a secondary process, such as, e.g., a thermal and/or UV process. In some examples, the polymeric resin formulation may include thermosetting resins and/or resins such as acrlyates, arylate copolymers, styrenes, and hybrids. Example epoxy resins may include Epon 828, a di-functional glycidyl ether based on bisphenol A, (obtained from Hexion Corporation, Columbus, OH), Epon 161, which is mulit-functional gylcidyl epoxy of a novolac oligomer (also available from Hexion), and/or Epon 160, which is a higher molecular weight analog of Epon 161(also available from Hexion).

[0026] In some examples, the resin composition may include one or more additives. Additives may include one or more suitable curing agents, rheology modifiers, such as, e.g., one or more thixotropes, surfactants, dispersants, diluents, air release agents, fillers, colorants (dyes), glass beads, and/or the like. In some examples, a rheological modifier may impart yield stress on the resin composition, and may cause the resin composition to exhibit gel-like properties. In some examples, the resin composition may include one or more appropriate rheological modifiers from available from Hexion Corp, Columbus, OH 43215, such as, e.g., Heloxy Modifier 67. In some examples, the resin composition may include BYK 525, 555, which are bubble releasing materials from BYK USA, Wallingford, CT; BYK-9010, which is a wetting/dispersing aid also from BYK; and/or A- 187, which is an epoxy functional silane available from GE Silicones. Examples colorants may include Ti0₂, burnt umber, FD&C blue #2, cardinal pthalo blue, and BK 5099. In some examples, appropriate fillers may be included in the resin composition, such as, e.g., Imsil A30 available from Unimin Specialty Minerals, Inc, New Canaan, CT 06840.

[0027] Some example insoles described herein may provide for one or more advantages. A base fabric with printed, protruding hard guard plates can be laminated to currently existing user removable insoles or insoles can be constructed with such fabric on their upper surfaces. An insole with guard plates as described herein may provide enhanced durability, e.g., the insole may not wear out as quickly from repeated insertions of a sock covered foot. This may increase the useable lifetime of the insole.

[0028] An insole with guard plates on its upper surface may provide increased comfort to the wearer's foot. For examples, the surface of the insole may be firm, but very flexible and adjust to the contours of the foot. The guard plate surface can also be treated to provide for a controlled level of friction between the sock or wearer's foot and the insole.

[0029] Such an insole may also provide improved temperature regulation with the footwear. For example, the air flow channels between the foot and the base layer of the insole may allow enhanced air movement with the footwear, especially during active use such as walking or running. Enhanced air flow may prevent hot zones from forming and provides a cooling effect within the footwear.

Additionally, humidity regulation may be provided by the air movement in the gap regions. Air movement prevents the accumulation of dampness from sweating in confined areas of the footwear.

[0030] As noted above, in some cases, an insole including a fabric layer with guard plates on the top surface may also be assembled by the user. A construction comprising a base fabric with guard plates on the top surface and an adhesive layer on the bottom surface can be applied by the user to the top surface of an existing insole. The adhesive may be temporarily covered by a removable material layer. The removable material layer may be a release liner configured to be removable from the adhesive layer. Such a construction may be applied to the existing insole by trimming it to the appropriate size, removing the removable adhesive covering layer and applying the construction to the surface of the insole.

[0031] In some examples, the construction may also beneficially comprise a stretchable base fabric and a stretchable adhesive layer. Stretchable fabric and adhesive may, for example, stretch 20% in width and/or length to accommodate protruding bumps that may be present in an existing insole design. By stretching in this manner, the construction can conform to any surface bumps or depressions in the existing insole without wrinkling or folding. Such wrinkles or folds could be uncomfortable to the user's feet.

[0032] EXAMPLE

[0033] Insoles with cured polymer guard plates on their top surfaces were made and tested. In one example, SuperFabric constructions with hexagonally shaped guard plates with 70 mil widths with 8 mil gaps between guard plates and constructions with 50 mil widths and 5 mil gaps were attached to existing foam insoles. This was done by spraying a contact type adhesive onto the top of the insole and on the SuperFabric side opposite the guard plates. The SuperFabric was then laminated to the top of the insole using hand pressure. The resulting insole was allowed to cure overnight and then inserted into boots for testing. Some users preferred the enhanced stimulation of the 70 mil guard plate pattern and some preferred the 50 mil guard plate pattern. For both constructions, feet slid into and out of the boots easily. The heat build-up in the boot was also less than that using a conventional foam insole after exerted walking.

Claims

CLAIMS:

1. A removable insole for footwear comprising:

a cushioning layer;

a woven or nonwoven fabric substrate attached to a top surface of the cushioning layer; and

a plurality of non-overlapping, guard plates separated by gaps between directly adjacent guard plates on a surface of the woven or nonwoven fabric substrate, the guard plates comprising a cured polymer resin partially penetrating into the surface of the woven or nonwoven fabric substrate to a depth less than a thickness of the woven fabric substrate to provide a mechanical bond between the woven fabric substrate and the guard plates.

2. The removable insole of claim 1, wherein the guard plates protrude out of the surface of the woven fabric substrate to define a thickness between greater than or equal to 5 mils and less than or equal to 40 mils.

3. The removable insole of claim 1, wherein guard plates are also present on the bottom surface of the cushioning layer.

4. The removable insole of claim 1, wherein the gaps between guard plates have a uniform width.

5. The removable insole of claim 1, wherein the width of the gaps is between 5 and 40 mils.

6. The removable insole of claim 1, wherein the guard plates each have a surface dimension between 30 and 150 mils.

7. The removable insole of claim 1 , wherein the fabric substrate is selected from the group consisting of polyester, nylon, cotton, aramid, polyethylene, or blends thereof.

8. The removable insole of claim 1, wherein the plurality of guard plates are hexagons printed in a repeating pattern.

9. A composite fabric assembly comprising:

a woven or nonwoven fabric substrate;

a plurality of non-overlapping, guard plates separated by gaps between directly adjacent guard plates on a surface of the woven or nonwoven fabric substrate, the guard plates comprising a cured polymer resin partially penetrating into the surface of the woven or nonwoven fabric substrate to a depth less than a thickness of the woven fabric substrate to provide a mechanical bond between the woven fabric substrate and the guard plates; and

an adhesive layer attached to a side of the fabric substrate opposite the guard plates, wherein the adhesive layer is configured to adhere to a surface of a removable insole.

10. The composite fabric assembly of claim 9, wherein the guard plates protrude out of the surface of the woven fabric substrate to define a thickness between greater than or equal to 5 mils and less than or equal to 40 mils

11. The composite fabric assembly of claim 9, further comprising a removable covering layer disposed on the adhesive layer.

12. The composite fabric assembly of claim 9, wherein the fabric substrate is stretchable.

13. The composite fabric assembly of claim 12, wherein the adhesive layer is stretchable.

14. The removable insole of claim 9, wherein the gaps between guard plates have a uniform width.

15. The removable insole of claim 9, wherein the width of the gaps is between 5 and 40 mils.

16. The removable insole of claim 9, wherein the guard plates each have a surface dimension between 30 and 150 mils.

17. The removable insole of claim 9, wherein the fabric substrate is selected from the group consisting of polyester, nylon, cotton, aramid, polyethylene, or blends thereof.

18. The removable insole of claim 9, wherein the plurality of guard plates are hexagons printed in a repeating pattern.