WO1998029000A1

WO1998029000A1 - Seam sealed waterproof breathable durable footwear

Info

Publication number: WO1998029000A1
Application number: PCT/US1997/019377
Authority: WO
Inventors: Thomas E. Casti; Douglas G. Graham; James A. Leininger
Original assignee: Gore Enterprise Holdings, Inc.
Priority date: 1997-01-02
Filing date: 1997-10-28
Publication date: 1998-07-09
Also published as: AU5000097A

Abstract

Footwear is disclosed having durable waterproof, breathable liner, said liner made of sewn body panels with tape sealed seams. The body panels are made of an abrasion-resistant fabric layer (13) and a sealable waterproof breathable layer (14); and optionally, a seam sealable layer. The abrasion-resistant fabric layer defines the exterior of the sewn body panels. The sealed seams (16) are on the interior of the foot covering and can be protected by an interior abrasion protecting layer which protects both the seam seal and the less durable seam sealable fabric. The construction protects against wear of the waterproof, breathable layer.

Description

TITLE OF THE INVENTION

SEAM SEALED WATERPROOF BREATHABLE DURABLE FOOTWEAR

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on Provisional application Serial No. 60/034,414, filed January 2, 1997.

FIELD OF THE INVENTION

This invention relates to waterproof footwear. More particularly, the invention relates to seam sealed, liquid waterproof but water-vapor-permeable, durable footwear.

BACKGROUND OF THE INVENTION

Common footwear constructions, such as those used in boots or shoes, employ waterproof constructions with a liquid waterproof but water-vapor- permeable, i.e., breathable, layer as a lining between the wearer's foot and the exterior parts of the footwear. The functional waterproof breathable layer is incorporated in a multi-layered lining fabric referred to as a waterproof breathable fabric. Waterproof breathable fabric panels are usually sewn together and sealed at the seams to form a waterproof liner within the footwear. One embodiment of the liner is called a bootie wherein the waterproof breathable fabric essentially surrounds the foot completely. There also exist non-bootie waterproof breathable fabric liner constructions other than a bootie wherein the lining fabric is sealed to other waterproof materials in the sole area rather than having the fabric extend completely underfoot as in the bootie. In either the case of the bootie or other constructions, the fabric panels which form the waterproof breathable liner are often an interior part of the footwear with the outer surface of the liner in proximity or contact with the inner surfaces of the footwear upper. The footwear upper may be composed of leathers, fabrics, and components such as eyelets, heel counters, steel safety toes, etc.

The waterproof breathable fabric panels of the liner are composed of multiple layers wherein the different layers may provide different functions, e.g. durability, waterproofness, fashion appeal, etc. In making the material for the panels of the liners, a thin waterproof (i.e. to liquid water) but breathable (i.e. water-vapor-permeable) membrane, layer is commonly laminated between fabric layers. Sometimes thin coatings on fabric are used as the waterproof breathable layer instead of a membrane. In order to permit transmission of water vapor through it, the waterproof layer is typically thin and relatively fragile unless protected. The outermost fabric layer of the liner should provide durability and abrasion resistance between the thin waterproof breathable layer and the footwear upper. A durable abrasion resistant outermost layer of the liner is important because this liner surface may rub against the inside surfaces of leather or fabric upper materials, and upper components such as heel counters, steel safety toes, rivets, etc. A common mode of failure due to water leakage in waterproof breathable fabric lined footwear is an abraded outermost layer of the liner which subsequently affects the integrity of the waterproof layer itself. The obvious solution would appear to be simply using more abrasion resistant material in the outermost layer of the liner, but this creates a problem because materials that provide the highest abrasion resistance severely reduce the effectiveness of the usual method used to seal the seams of the fabric panels for waterproofness. Sewn seams in footwear liners are usually rendered waterproof by means of a material, such as a seam tape with a thermoplastic adhesive, placed over the seam on the outermost surface. The thermoplastic adhesive sealant material must penetrate through the outermost fabric layer to reach the membrane and fill the spaces within the fabric in order to achieve a waterproof seal. A fabric layer with a relatively open lightweight structure is commonly used in the outermost layer of the liner because it is amenable to seam sealing, but this type of fabric is poor in durability. The seam sealing material is placed on the outermost layer of the liner rather than the inside for reasons which may include difficulty in applying tape within the confined space inside the liner, a need to keep the inside of the liner cosmetically appealing, and difficulty in achieving an effective seal on typical interior layer materials.

Exemplary waterproof but water-vapor-permeable, i.e., breathable, layers include membranes disclosed in U.S. Patent Nos. 3,953,566 and 4,187,390 which disclose a method and article for making a form of expanded polytetrafluoroethylene (PTFE) that has both waterproof and breathable properties. U.S. Patent No. 4,194,041 discloses an improvement on that material. The materials of these patents have been used widely in waterproof breathable outdoor garments such as jackets, pants, gloves, boots and socks. U.S. Patent No. 4,809,447 to Pacanowsky, describes a multi-component waterproof, sock-type article having a waterproof, components and having waterproof seam tape covering seams.

Thus, footwear manufacturers have had to compromise between being able to seal the lining fabric seams and being able to use a durable material. A need exists for footwear that employs a waterproof lining which has a durable outer layer to protect the integrity of a waterproof breathable layer from abrasion against the footwear upper while also allowing the seams of the waterproof lining to be effectively sealed.

SUMMARY OF THE INVENTION

This invention is directed to waterproof footwear having a sole and an upper, i.e., a boot or shoe, which has inside it a liner which is comprised of a waterproof breathable functional layer and a durable abrasion resistant outermost layer and optional inner layers, said liner made of panels seamed together to conform with at least a portion of the inside of the upper, and said liner sealed to waterproof the seams by a material covering the seams on the inside of the waterproof liner. In one embodiment, the abrasion resistant outermost layer is a durable textile fabric. It is adhered to the outside of a thin waterproof breathable functional layer, and the joined panels are made waterproof by a waterproof seam sealing tape located on the inside of the waterproof breathable layer. There may be an additional inner lining inside of the interior surfaces of the waterproof breathable layer and the interior surface of the seam tape. The inner lining may contain insulating materials. Padding, insulating materials, and other similar components may be positioned between the interior surface of the seam sealed waterproof breathable layer and the inner lining. The interior surface of the waterproof breathable layer may be adhered to the inner lining or to other components in contact with said layer's interior surface.

In a second embodiment, the liner may be comprised of an outermost abrasion resistant fabric adhered to the outside of a waterproof breathable functional layer and with a seam sealable fabric layer adhered to the interior surface of said waterproof breathable layer. The joined liner panels are sealed to make the seams waterproof by a waterproof seam sealing tape located on the surface of the seam sealable fabric layer. There may be an additional inner lining inside of the interior surfaces of the seam sealable fabric layer and the interior surface of the seam tape. The additional inner lining may contain insulating materials. Padding, insulating materials, and other similar components may be positioned between the interior surface of the seam sealed fabric layer and the inner lining. The interior surface of the seam sealed fabric layer may be adhered to the inner lining or to other components in contact with said layer's interior surface.

In either embodiment, the liner may be a bootie or other construction as described in the first paragraph of the Background section.

By seam sealable fabric is meant a fabric which is amenable to being sealed using the common methods of making waterproof seams such as applying a seam sealing tape containing a thermoplastic adhesive or sealant.

The seam sealable fabric provides some durability to the functional waterproof breathable layer, but the choice of fabrics and the level of durability which can be achieved is limited by the need to use a fabric structure which can be penetrated by the seam tape adhesive. By waterproof is meant the material or seam can withstand 0.1 psi, preferably 0.2 psi, or more hydrostatic pressure for 1 minute without leaking or seeping any water.

By abrasion-resistant fabric is meant a material that resists a complete wear through after at least 300,000 revolutions, when abraded as part of a laminated fabric in a dry Martindale abrasion test according to test method

SATRA PM 31 : 1993 Method = A. Fabrics with higher abrasion resistance, such as 600,000 or 1 ,800,000 revolutions can be used.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a view of one type of footwear of the invention.

Figure 2 Is a cutaway view taken along line 2-2 of Figure 1 and depicts the non-bootie embodiment.

Figure 3 is a cutaway view taken along 2-2 of Figure 1 and depicts the bootie embodiment of the invention.

Figures 4, 5 and 6 are taken along 2-2 of Figure 1 and depict other embodiments of the invention.

Figure 7 is an exploded view of the circled portion of Figure 3.

DETAILED DESCRIPTION OF THE INVENTION

The present invention advances the art and techniques for creating durable waterproof, breathable, seam sealed footwear. The footwear has inside a waterproof breathable liner made of a fabric laminate. The laminate is made of an outermost layer that is an abrasion-resistant durable fabric next to the inside of the footwear upper. The next layer of the laminate, which is inside of the abrasion-resistant durable fabric, is a functional layer made of a liquid- waterproof, water-vapor-permeable film. In a second embodiment, a third layer of a seam sealable fabric is laminated to the inside of the functional film layer. In either case, the seam seals are located on the interior layer.

To make the liner, the laminate is first made and then cut into panels and sewn or bonded into a footwear liner configuration with the durable fabric on the inside. The seams are then sealed on the seam sealable side which is currently on the outside, preferably with a waterproof tape. The configuration is then inverted so that the seam sealable side and seam sealing tape are now on the inside and the abrasion resistant durable fabric layer is on the outside. Alternatively, the liner can be made with the durable fabric on the outside and the liner inverted so the seams can be sealed on the outside of the functional layer or to the third backing layer, and this construction re-inverted to result in the durable layer being on the outside. In either method, the durable fabric in the final product is on the outside and serves to increase the wear-resistance and life of the outside surface of the construction, and thus increase the waterproof life of the footwear.

An optional separate second liner, referred to as an inner lining, of an abrasion-resistant fabric may be added to the first seam sealed waterproof liner. This second inner lining is inserted into the first liner in proximity with the seam tape and the seam sealed surface and optionally can be adhered thereto, but need not be. This inner lining protects the seam tape and the inside layer of the laminated first liner from abrasion and can also provide other benefits such as fashion appeal, thermal insulation, etc. To provide even further abrasion protection, the inner lining may be adhered to the inside of the first liner. The adhesive prevents wear due to rubbing motion between the inner lining and the seam tape, the seam sealable fabric, or waterproof breathable layer.

The adhesive used to adhere the inner lining may be a discontinuous, heat fusible thermoplastic material preapplied to the laminate layer before the inner lining is applied. Heat and pressure are applied to create a bond between the inside of the first seam sealed waterproof liner and the inner lining with the fuseable thermoplastic material.

The inner lining may be present to improve cosmetic appearance. It may contain an insulation fayer. The inner lining may be composed of multiple layers which could include insulation, padding or stiffening materials. The insulation can be a plastic foam, a quilted batting, a felt type material, or the like, preferably located between the seam sealed liner and a fabric inner lining, and is optionally bonded to the inside surface of the seam sealed liner. The insulating material may itself be the inner lining. The multiple layers of the inner lining may cover all or only a partial area of the first sealed liner.

In the case where the footwear has the liner in the form of a bootie, the footwear is typically completed by first attaching the bootie liner to the top line area of the footwear upper. The bootie liner is then slipped onto a last, an insole is typically added to the bottom of the bootie liner, the upper is lasted, and a sole is attached.

In the case where the footwear has the liner in a form other than a bootie, the bottom edges of the liner are joined and sealed to other waterproof materials in the lower part of the footwear. In one example, the tops of the liner and upper are attached to one another, the bottom of the liner is flat lasted to a sealant coated insole board forming a waterproof seal, the upper is lasted and a sole is attached, stitched, or molded on.

Referring now to the drawings, in which similar reference characters designate corresponding parts throughout the several views, Figure 1 depicts one embodiment of the waterproof footwear of the invention in the form of a boot 10 having a sole 11 and an upper 12. The liner component of the invention is not shown since it is inside boot 10. In an embodiment where the liner extends all the way to the top of the upper, the inner lining of the liner is partially seen in the area designated by 15. Figures 2, 3, 4 and 5 show cutaway views taken along 2-2 of Figure 1. In

Figure 2, the liner is in the form of a non-bootie embodiment and it has been inverted during construction so the seam sealing tape is on the inside relative to the waterproof breathable layer of the liner. In Figure 3, the liner is in the form of the bootie embodiment, and it also has been inverted during construction so the seam sealing tape is on the inside. As can be seen, the major difference is that in the bootie construction, the liner is continuous and essentially surrounds a foot. In the non-bootie construction, the liner does not extend completely underfoot. In Figures 2, 3, 4 and 5, the footwear upper is shown as 12 and the sole as 11. The durable abrasion resistant outer layer of the liner is shown as 13, the waterproof, breathable functional layer is 14. The seam sealable fabric layer is optional and is shown as 22 only in Figure 5. The inner lining layer is 15. This inner lining layer 15 is optional and is not present in either Figure 4 or Figure 5. Seam threads are shown as 16 with seam tape 17 covering the seam.

In Figure 2, the insole 18 covers the opening of the non-bootie liner construction and the liner is sealed to the inside by sealant material 19. In Figures 3, 4 and 5, insole 18 is located outside the bootie liner construction and is adhered to the bootie liner as well as both the upper 12 and the sole 11. In Figures 3 and 4, it is noted that there are two seams present in these bootie liner constructions. It is understood a bootie may contain more seams.

In Figure 5 is shown a bootie liner construction with one seam in the cross sectioned area.

In Figure 5, the inner layer 22 of the laminate formed by layers 13, 14 and 22, is a seam sealable fabric to which the seam sealing tape 17 is applied.

Figure 6 is similar to Figures 2-4, but also depicts presence of a padding or insulating material 20 in addition to inner lining 15. Figure 7 is an exploded view of the circled portion of Figure 3 and depicts an embodiment where the inner lining 15 is adhered to functional layer 14 by discontinuous adhesive 21.

The present invention overcomes problems of abrasion by the footwear upper against the outside of waterproof breathable liners by constructing the liner so that in the finished product durable, abrasion-resistant (wear) layer 13

(the abrasion-resistant fabric layer) is on the outside of the waterproof breathable functional layer 14. Panels of the laminate are cut and sewn into a bootie or non-bootie footwear liner. At this point, the durable abrasion-resistant layer 13 is on the inside. The seams are sealed on the outside with seam sealing tape 17.

The liner construction can be turned inside out after the seams are sealed, and then the optional inner lining fabric inserted into the inside-out construction, and preferably, but not necessarily , bonded to the waterproof breathable layer or seam-sealable fabric as the case may be. Alternatively, the optional second inner lining fabric may be placed over the seam sealed waterproof liner and then the layers are turned inside out. If a second lining fabric is used it now finally becomes the inner lining.

The added inner lining forming the innermost layer may cover the inside of the footwear completely or partially and may have disposed between it and the seam sealed layer additional materials, for example foam paddings or sections of insulation material.

The footwear may be constructed with a non-bootie method where the waterproof breathable liner is joined and sealed against leakage to waterproof materials, other than the waterproof breathable liner itself in the sole region of the footwear.

The fabric that is compatible with seam sealing tape, i.e., the seam sealable fabric or the fabric amenable to seam sealing, is one that has an "open" construction, i.e., spaces, so that adhesives can flow into the spaces easily. Such fabrics are usually lightweight knits or non-wovens, and can be made of nylon, polyester, or the like.

The waterproof, water-vapor-permeable (breathable) layer can be any such material, such as a breathable polyurethane, polyetherester, porous polyolefin, or the like, but is preferably a porous polytetrafluoroethylene film such as a porous expanded polytetrafluoroethylene film having a structure of interconnected nodes and fibrils, as described in U.S. Patent Nos. 3,953,566 and 4,187,390. These patents describe the preferred material and processes for making them. The porous polytetrafluoroethylene film should have a thickness in the range 3 to 1 ,000 micrometers, preferably in the range 5 to 100 micrometers; a pore volume in the range 20 to 98 percent, preferably in the range 50 to 90 percent; and a nominal pore size in the range 0.05 to 15 micrometers, preferably in the range 0.1 to 2 micrometers.

Suitable abrasion-resistant fabric layers for use with the present invention includes but is not limited to woven fabrics, non-woven fabrics and knit fabrics having a dense structure. Representative fabrics can be made of nylon, polyester, Kevlar, polyolefins, etc.

The seams formed in sewn configurations of the laminate may be sealed by applying a waterproof seam sealing tape or other form of sealant. The preferred means of sealing the seams is by using seam sealing tape, such as

GORE-SEAM ™ tape available from W. L. Gore and Associates, Inc., Elkton,

MD. Such a tape may comprise a hot-melt adhesive which seals and bonds durably to fabrics. A useful seam sealing tape is described in U.S. Patent No.

5,162,149. A seam sealant or tape provides additional waterproofing to the overall fabric and prevents water leakage in seam areas.

Example 1

A three layer fabric laminate of waterproof, water-vapor-permeable expanded PTFE sheet obtained from W. L. Gore & Associates, Inc. was laminated by use of a discontinuous adhesive between a seam-sealable nylon tricot knit (1.5 oz./yd.²) and a durable, abrasion-resistant tightly woven Taslan nylon 2.8 oz./yd.² nylon. The laminate was cut into a bootie liner pattern of three pieces, and sewn to form a first liner with the tricot knit on the outside (because it is seam sealable). Then the seams were sealed under pressure with a thermoplastic heat sealable seam tape, such as GORE-SEAM™ seam tape (available from W. L. Gore & Associates, Inc., Elkton, Maryland). This tape is a tape of a thermoplastic polyurethane. The liner was then turned inside out to result in a configuration with the seam seals on the inside.

A second insulating fabric was made for use as an inner liner. This inner liner was made of a quilted fabric of Cambrella® nonwoven nylon, Thinsulate® insulation and a lightweight nonwoven, spun bonded nylon. This second liner was placed inside the inverted first liner and bonded to the inside by a thermoplastic adhesive in the form of a web using a heated press. This combined liner was inserted into an unlined boot to make a durable waterproof breathable boot.

Example 2

A two layer fabric laminate was employed of an abrasion resistant 160 denier Cordura nylon woven fabric and a waterproof, water-vapor-permeable expanded PTFE sheet as used in Example 1. Thermoplastic polyamide adhesive dots were deposited on the side of the PTFE away from the woven fabric. The laminate was cut into a bootie liner pattern of two pieces and sewn to form a first liner with the thermoplastic adhesive dot coated PTFE surface on the outside. Then the seams were sealed under pressure with a thermoplastic heat sealable seam tape, such as GORE-SEAM™ seam tape used in Example 1. This liner was then turned inside out to result in a configuration with the seam seals and adhesive dots on the inside.

A second liner was made for use as an inner lining layer. This is made of a single layer of nylon tricot knit fabric sewn together in two panels.

This second bootie was placed inside the inverted first bootie and was bonded to it by the thermoplastic adhesive dots located on the PTFE surface of the first bootie using a heated press. This combination was stitched at its top around the collar periphery of a boot upper. The bonded two-bootie combination was put on a last. The footwear upper was lasted and a boot bottom applied. It will be appreciated that modifications are possible without materially departing from the novel teachings, and advantages which are described herein. Accordingly, all such modifications are intended to be included within the scope of the present invention, as defined by the following claims.

Claims

WE CLAIM:

1. Footwear having a sole and an upper, said footwear having within it a liner, said liner comprised of a laminate of an abrasion-resistant outer layer, and a waterproof, water vapor permeable functional layer inside the outer layer; said liner being shaped to conform with at least a portion of the inside of the footwear, and said liner made of joined sections seamed together in which the seams are sealed by a waterproof material located on the inside of the liner.

2. The footwear of Claim 1 wherein the liner is in the form of a bootie which encloses the bottom and all of the sides of the foot and may extend up to the top line of the footwear.

3. The footwear of Claim 1 wherein the liner material does not enclose the bottom of the foot and is joined and sealed to other waterproof materials in the sole or insole region of the footwear.

4. The footwear of Claim 1 , 2 or 3 wherein the material placed over the liner seams to seal them is in the form of a tape.

5. The footwear of Claim 1 , 2 or 3 wherein an inner lining is inside said liner and adhered to the liner.

6. The footwear of Claim 1 , 2 or 3 wherein an inner lining is inside said liner and is not adhered to the liner.

7. The footwear of Claims 1 , 2 or 3 wherein the liner laminate includes an additional fabric layer located between the functional layer and the seam sealing material.

8. The footwear of Claims 1 , 2 or 3 wherein the footwear is a boot.

9. The footwear of Claims 1 , 2 or 3 wherein the footwear is a shoe.

10. A method of forming a foot enclosure or portion thereof comprising the steps:

(a) providing a laminate comprising a waterproof breathable layer and an abrasion-resistant fabric layer; and optionally a seam sealable fabric layer wherein the waterproof breathable layer is sandwiched between the seam sealable fabric layer and the abrasion-resistant fabric layer;

(b) cutting the laminate into panels;

(c) joining the panels together to form seams of a foot enclosure in a manner which results in the abrasion-resistant fabric layer defining the interior surface; _

(d) sealing the external side of the seams with a waterproof material; (e) inverting the foot enclosure so that the abrasion-resistant fabric layer defines the exterior surface; and the sealed seams are located on the interior of the foot enclosure; and

(f) adding an inner lining and adhering it to the interior surface.

11 A method of forming a foot enclosure or portion thereof comprising the steps:

(b) cutting the laminate into panels;

(c) joining the panels together to form seams of a foot enclosure in a manner which results in the abrasion-resistant fabric layer defining the interior surface;

(d) sealing the seam or seams of the external side with a waterproof material ;

(e) covering the foot enclosure with a lining layer, and optionally adhering it to the laminate; and (f) inverting the foot enclosure so that the abrasion-resistant fabric layer is on the outside.

12. The method of Claim 10 or 11 wherein the waterproof sealing material is a waterproof tape.

13. The method of Claim 10 or 11 wherein the foot enclosure is a footwear liner.

14. The method of Claim 10 or 11 wherein the foot enclosure is a footwear upper.