WO2003053678A1

WO2003053678A1 - Method of sealing a sewn seam

Info

Publication number: WO2003053678A1
Application number: PCT/US2001/030626
Authority: WO
Inventors: Donald R. Cohee
Original assignee: Ilc Dover, Inc.
Priority date: 2001-10-02
Filing date: 2001-10-02
Publication date: 2003-07-03
Also published as: AU2001298058A1

Abstract

A method of sealing a sewn seam (100) which introduces a sealant (110) into the seam (100) prior to sewing is relatively simple, adaptable for use in various types of seam configurations, capable of being employed in a mass production environment, and provides the requisite degree of sealing between the seam components. The method includes (a) applying a sealant (110) between a first piece of material (120) to be joined and a second piece of material (130) to be joined, and (b) joining the first piece of material (120), the applied sealant (110), and the second piece of material (130) with stitches (140) so as to provide the sealed sewn seam (100). Advantages associated with the method of sealing include not only its simplicity, but the requisite integrity of the sealed seam (100), which is both waterproof and airtight. By virtue of its simplicity, the method is adaptable for use with virtually all types of sewn seams (100), and all types of fabric and stitching materials.

Description

METHOD OF SEALING A SEWN SEAM BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to a method of sealing a sewn seam. The invention relates more specifically to a method of sealing a sewn seam which introduces a sealant into the seam prior to sewing.

2. Description of Related Art

A disadvantage of using a sewn seam in waterproof or airtight product applications has always been the difficulty associated with sealing the holes in the materials which are produced by the needle penetrating the material during the stitching operation.

Historically, attempts have been made to increase the integrity of such conventional stitched seams by secondary processes, i.e., processes employed after the seam has been sewn. These attempts have included either sealing the outside of the sewn seam with a luting compound, or applying a covertape which is either heat sealed or cemented to the sewn material. Disadvantages of such conventional approaches to sealing include not only the additional process steps involved, but that the resultant seam is often stiff and bulky.

Therefore, a general need exists for a method of sealing a sewn seam which overcomes the aforementioned process complexity and seam integrity issues associated with conventional methods.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method of sealing a sewn seam which is relatively simple, adaptable for use in various types of seam configurations, and capable of being employed in a mass production environment, and which also provides the requisite degree of sealing between the components of the seam.

Accordingly, in a preferred embodiment the present invention advantageously relates to a method of sealing a sewn seam which introduces a sealant into the seam immediately prior to stitching.

In a typical embodiment, the method comprises (a) applying a sealant between a first piece of material to bejoined and a second piece of material to bejoined, and (b) joining the first piece of material, the applied sealant, and the second piece of material with stitches so as to provide the sealed sewn seam. By virtue of its simplicity, the method is readily adaptable for use in various types of seam configurations. For example, when employed with a double feld seam (Fig.2), the method comprises the steps of (a) folding back a length of a first piece of material so that a first interior surface portion of the first piece of material is located opposite a second interior surface portion of the first piece of material, and folding back a length of a second piece of material so that a first interior surface portion of the second piece of material is located opposite a second interior surface portion of the second piece of material; (b) forming a preform by orienting the first piece of material and the second piece of material such that the folded back length of the first piece of material is disposed between the first interior surface portion of the second piece of material and the second interior surface portion of the second piece of material, and the folded back length of the second piece of material is disposed between the first interior surface portion of the first piece of material and the second interior surface portion of the first piece of material; (c) applying a sealant between (i) an exterior surface portion of the folded back length of the first piece of material and the second interior surface portion of the second piece of material and (ii) an exterior surface portion of the folded back length of the second piece of material and the second interior surface portion of the first piece of material; and (d) joining the first piece of material, the applied sealant, and the second piece of material with stitches so as to provide the sealed sewn seam.

Advantages associated with the method of sealing include not only its simplicity, but the requisite integrity of the sealed seam, which is both waterproof and airtight. As used throughout the specification, the term "waterproof is intended to include fluids other than water, and the term "airtight" is intended to include gases other than air. By virtue of its simplicity, the method is adaptable for use with virtually all types of sewn seams, and all types of fabric and stitching materials.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features, and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiments and the accompanying drawings. As depicted in the attached drawings: FIG. 1 is a cross-sectional view of a lap seam sealed according to the present invention.

FIG. 2 is a cross-sectional view of a double feld seam sealed according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be disclosed in terms of the currently perceived preferred embodiments thereof. The present invention provides a method of sealing a sewn seam which is relatively simple, adaptable for use in various types of seam configurations, and capable of being employed in a mass production environment, and which also provides the requisite degree of sealing between the components of the seam. According to the present invention, a sealant/adhesive material is introduced into the interior of the seam immediately prior to sewing. The sealant/adhesive material performs "Oth an adhesive function (i.e., providing adhesion between the pieces ofmaterial to bejoined) and a sealing function (i.e., sealing not only between joined pieces ofmaterial, but in the holes in the material which result from the needle during the sewing process). For purposes of brevity, the sealant/adhesive material will hereinafter be referred to as "sealant."

In general, the method of sealing a sewn seam comprises, sequentially, (a) applying a sealant between a first piece ofmaterial to bejoined and a second piece ofmaterial to be joined, and (b) joining the first piece ofmaterial, the applied sealant, and the second piece ofmaterial with stitches so as to provide the sealed sewn seam. For example, FIG. 1 is a cross-sectional view of a lap seam 100 sealed according to the present invention. The method of sealing comprises (a) applying a sealant 110 between a first piece ofmaterial to bejoined 120 and a second piece ofmaterial to bejoined 130, and (b) joining the first piece ofmaterial 120, the applied sealant 110, and the second piece ofmaterial 130 with stitches 140 so as to provide the sealed sewn seam. By virtue of its simplicity, the method is readily adaptable for use in various types of seam configurations. For example, when employed with a double feld seam 200 (FIG. 2), the method comprises the steps of (a) folding back a length 221 of a first piece of material 220 so that a first interior surface portion 222 of the first piece ofmaterial 220 is located opposite a second interior surface portion 223 of the first piece ofmaterial 220, and folding back a length 231 of a second piece of material 230 so that a first interior surface portion 232 of the second piece of aterial 230 is located opposite a second interior surface portion 233 of the second piece of material 230; (b) forming a preform by orienting the first piece ofmaterial and the second piece ofmaterial such that the folded back length of the first piece of material is disposed between the first interior surface portion of the second piece ofmaterial and the second interior surface portion of the second piece ofmaterial, and the folded back length of the second piece ofmaterial is disposed between the first interior surface portion of the first piece ofmaterial and the second interior surface portion of the first piece of material; (c) applying a sealant between (i) an exterior surface portion of the folded back length of the first piece ofmaterial and the second interior surface portion of the second piece of material and (ii) an exterior surface portion of the folded back length of the second piece ofmaterial and the second interior surface portion of the first piece ofmaterial; and (d) joining the first piece of material, the applied sealant, and the second piece ofmaterial with stitches so as to provide the sealed sewn seam.

The process of stitching compresses the materials together and forces the sealant into any spaces between the pieces ofmaterial that are joined, and the stitch holes which contain the stitching material. The sealant is selected so as to bond (i) to the pieces ofmaterial, and (ii) to the stitching material (typically thread or monofilament). In addition, the sealant is selected so as to have a very high elongation such that the seal will be maintained under loading of the joined pieces ofmaterial (which loading tends to elongate the normal shape of the stitching holes). By introducing the sealant immediately prior to the stitching operation, the need for the aforementioned conventional secondary processes is eliminated.

In a typical embodiment, the sealant is applied in an uncured state. In this embodiment, the method of sealing a sewn seam comprises (a) applying an uπcured sealant between a first piece of material to bejoined and asecond piece ofmaterial to bejoined; (b) joining the first piece ofmaterial. the applied uncured sealant, and the second piece ofmaterial with stitches; and (c) curing the applied uncured sealant so as to provide the sealed sewn seam. In this embodiment, the stitches maintain compression between the first and second pieces ofmaterial while the applied sealant cures. This compression also causes the uncured sealant to flow into the apertures caused by the needle or other stitching device passing through the pieces of material.

In another embodiment, however, the sealant can be applied in a cured state. In this embodiment, which is essentially "self-sealing," thread tension forces the sealant into the spaces to be sealed. These spaces include, typically, any spaces between the pieces ofmaterial that are joined, and the stitch holes punctured in the pieces ofmaterial and the cured sealant by the needle or other stitching device during the sewing process. Since it is applied in the cured state, there is no adhesion of the sealant to the materials and thread.

In both the uncured embodiment and the cured embodiment of the method, the sealant has a very high elongation and is preferably capable of being cured at room temperature. In a typical embodiment, the sealant is selected from the group consisting of two-part reactive compounds and moisture curing compounds (e.g., room temperature vulcanizing silicones that cure with moisture).

Typical sealants include materials such as silicones and urethanes. For example, a typical two-part silicone gel is that sold under the trademark "SYLGARD 3-6636" (commercially available from Dow Chemical, Midland, Michigan).

In still another embodiment, the method can facilitate sealing a sewn seam comprising a plurality of pieces ofmaterial. In this embodiment, the method comprises the steps of (a) applying a sealant between each of the plurality of pieces ofmaterial to bejoined, and (b) joining the plurality of pieces ofmaterial and the applied sealant between each of the plurality of pieces of aterial with stitches so as to provide the sealed sewn seam.

EXAMPLE To demonstrate the seam sealing ability of the present invention, two different types of seams

- a 0.5 inch lap seam (Fig. 1) and a 0.5 inch double feld seam (Fig.2) - were prepared as follows. The material to be sewn was urethane coated nylon, and the thread was size F polyester. The sealant used was SYLGARD 3-6636 two-part silicone gel. The silicone was mixed (15 minute pot life) and immediately applied to the urethane coated nylon. In the lap seam, the silicone was applied in a single layer as described above and as depicted in Fig. 1 , i.e., between the interior surface of each of the first and second pieces ofmaterial to be joined. In the double feld seam, the silicone was applied in two separate layers as described above and as depicted in Fig. 2, i.e., between i) the interior surface of a first piece of material to bejoined and ii) the exterior surface of that portion of a second piece of material to bejoined which is folded to form the seam. Following application of the silicone. the seams were stitched using type 301 stitches (size 21 sewing needle). The double feld seam included one row of stitches (8-10 stitches per inch), and the lap seam included two rows of stitches (12-14 stitches per inch) spaced 0.25 inch apart. After curing, the seams were tested for leakage by mounting the material seam in a flanged test fixture, pressurizing the bottom with air, and flooding the top with water. Both seams exhibited no leakage when pressurized.

The application of the sealant to the pieces ofmaterial can be accomplished in various ways.

In the method employed in the Example, the mixed sealant was applied manually by brush prior to sewing. Other coating techniques known in the art, however, can be utilized, such as spraying, dipping, falling curtain, and roll coating.

Another production method of applying the sealant is to incorporate an application head (e.g., an injection or extrusion head) into the material "folder" (i.e., the device which aligns the pieces of material prior to the sewing step), and have the material pick up the sealant as the material passes through the folder prior to sewing. In this embodiment of the invention, an apparatus for sealing a sewn seam comprises (a) means for aligning the first piece of material and the second piece of material; (b) means for applying a sealant between the aligned first piece ofmaterial and second piece ofmaterial; and (c) means for joining the aligned first piece ofmaterial. the applied sealant, and the aligned second piece ofmaterial with stitches so as to provide the sealed sewn seam. By virtue of the means for applying the sealant, the sealant can be extruded or knife coated onto the material through the application head. To facilitate the application of the sealant, the application head is typically located just upstream of the sewing needle. In another embodiment of the production method of applying the sealant, the sealant can be applied during the sewing process. In this embodiment, the sealant is extruded or coated onto the material during the sewing process by virtue of an injection port adjacent to the needle. The present invention, therefore, provides a method of sealing a sewn seam which is relatively simple, adaptable for use in various types of seam configurations, and capable of being employed in a mass production environment, and which also provides the requisite degree of sealing between the components of the seam. By virtue of its simplicity, the method is adaptable for use with virtually all types of sewn seams, and all types of fabric and stitching materials.

While only certain preferred embodiments of this invention have been shown and described by way of illustration, many modifications will occur to those skilled in the ait. For example, while the method has been exemplified by describing its use for sealing lap sewn and double feld seams, it is equally applicable to any seam configuration requiring a seal which exhibits the ease of application and structural integrity of that achieved with the present invention.

By way of further example of modifications within the scope of this invention, while the method has been described as comprising joining the pieces of material with stitches, another embodiment could comprise joining the pieces ofmaterial with another type of structural connection

(e.g., ultrasonic stitching) which is capable of compressing the joined materials while the sealant cures.

By way of further example of modifications within the scope of this invention, while the method has been described as comprising the use of a sealant exemplified in one embodiment as a silicone or a urethane, the sealant could comprise a different compound, or mixtures thereof, which is capable of both being easily applied, and providing the requisite seal, for any particular application. By way of further example of modifications within the scope of this invention, while the method has been described as comprising joining the pieces ofmaterial," it should be appreciated that the "material" can comprise woven materials, or non-woven materials, including, for example, films, or mixtures of such materials, such as. for example, a film with an attached backing material. It is, therefore, desired that it be understood that it is intended herein to cover all such modifications that fall within the true spirit and scope of this invention.

Claims

What is claimed is: 1. A method of sealing a sewn seam comprising: (a) applying a sealant between a first piece of material to be joined and a second piece of material to bejoined; and (b) joining said first piece ofmaterial, said applied sealant and said second piece ofmaterial with stitches so as to provide said sealed sewn seam.

2. A method of sealing a sewn seam according to claim 1 , wherein said sealant is applied in a cured state.

3. A method of sealing a sewn seam according to claim 1 , wherein said sealant has a high elongation and is capable of being cured at room temperature.

4. A method of sealing a sewn seam according to claim 3, wherein said sealant is selected from the group consisting of two-part reactive compounds and moisture curing compounds.

5. A method of sealing a sewn seam according to claim 3 , wherein said sealant is selected from the group consisting of silicones and urethanes.

6. A method of sealing a sewn seam comprising: (a) applying an uncured sealant between a first piece of material to be joined and a second piece of material to bejoined; (b) joining said first piece ofmaterial, said applied uncured sealant and said second piece of material with stitches; and (c) curing said applied uncured sealant so as to provide said sealed sewn seam.

7. A method of sealing a sewn seam comprising a plurality of pieces of material, said method comprising the steps of: (a) applying a sealant between each of said plurality of pieces of material to be joined; and (b) joining said plurality of pieces ofmaterial and said applied sealant between each of the plurality of pieces ofmaterial with stitches so as to provide said sealed sewn seam.

8. A method of sealing a sewn seam comprising a first piece ofmaterial and a second piece ofmaterial, said method comprising the steps of: (a) folding back a length of said first piece ofmaterial so that a first interior surface portion of the first piece ofmaterial is located opposite a second interior surface portion of the first piece of material, and folding back a length of said second piece of material so that a first interior surface portion of the second piece of material is located opposite a second interior surface portion of the second piece of material; (b) forming a preform by orienting said first piece ofmaterial and said second piece ofmaterial such that said folded back length of the first piece of material is disposed between said first interior surface portion of the second piece ofmaterial and said second interior surface portion of the second piece ofmaterial, and said folded back length of the second piece ofmaterial is disposed between said first interior surface portion of the first piece ofmaterial and said second interior surface portion of the first piece ofmaterial; (c) applying a sealant between (i) an exterior surface portion of said folded back length of the first piece ofmaterial and said second interior surface portion of the second piece ofmaterial and (ii) an exterior surface portion of said folded back length of the second piece ofmaterial and said second interior surface portion of the first piece of material; and (d) joining said first piece ofmaterial, said applied sealant, and said second piece ofmaterial with stitches so as to provide said sealed sewn seam.

9. An apparatus for sealing a sewn seam comprising a first piece ofmaterial and a second piece ofmaterial, said apparatus comprising: (a) means for aligning said first piece of material and said second piece of material; (b) means for applying a sealant between said aligned first piece ofmaterial and second piece ofmaterial; (c) means for joining said aligned first piece ofmaterial. said applied sealant, and said aligned second piece ofmaterial with stitches so as to provide said sealed sewn seam.

10. An apparatus for sealing a sewn seam according to claim 9. wherein said means for applying the sealant is an injection or extrusion head disposed in said means for aligning the first piece ofmaterial and the second piece ofmaterial.