US20050097658A1

US20050097658A1 - Cushioning laminate insert for a garment shoulder strap, and method for making the same

Info

Publication number: US20050097658A1
Application number: US10/936,760
Authority: US
Inventors: Justina Lyons; Charles Sipes
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-09-09
Filing date: 2004-09-09
Publication date: 2005-05-12

Abstract

The present invention relates to a cushioning laminate insert for a garment shoulder strap, such as a brassiere strap. The cushioning laminate insert of the invention includes: (1) a first outer fabric layer; (2) a central cushioning area of cured polyurethane elastomer cushioning material; and (3) a second outer fabric layer. One surface of the first and second outer fabric layers is laminated with a thermoplastic urethane (“TPU”) film. The laminated surface of the first outer fabric layer is covalently bonded to a first lateral surface of the central cushioning area, and the opposite lateral surface of the central cushioning area is self-adhered to the laminated surface of the second outer fabric layer in an open-sandwich configuration to thereby form the cushioning laminate insert. Garment shoulder straps including the cushioning laminate insert of the invention, as well as methods for making the cushioning laminate insert are also provided.

Description

FIELD OF INVENTION

The present invention relates to cushioning laminate inserts for garment shoulder straps, such as brassiere straps. The present invention also relates to a method for making such inserts and to garment shoulder straps including such inserts.

BACKGROUND OF THE INVENTION

A well-known problem associated with garment shoulder straps is the discomfort caused by the strap on the shoulder of the wearer. Specifically, the brassiere strap may cause an indentation in, or irritation of, the skin of the shoulder. Numerous attempts have been made to relieve this discomfort. Some attempts have included the use of shoulder pads of cotton or foam rubber that are interposed between the strap and the wearer's shoulder, or releasably attached to the strap. Such pads have proven to be bulky and unsightly, as well as inconvenient since they have a tendency to become disengaged from, or shift position on the shoulder strap. For example, U.S. Pat. No. 4,638,513 to Woods proposes a layered and sewn elastic strap as a means of solving this problem. U.S. patent application Ser. No. 2003/0040256 A1 to Waitz discloses a curvilinear shoulder strap that includes an interior hollow portion which is filled with a cushioning material, such as silicone gel. Numerous other United States patents, for example, U.S. Pat. Nos. 4,795,399, 4,612,935 and 4,945,576 disclose various configurations of pads for placement on or under brassiere straps to diffuse and spread the load of the strap on the shoulder.
Although considerable effort has been devoted to solving these problems, the various prior art solutions have been less than successful for a number of reasons. First, although separate pads can provide a useful addition to a favorite garment, it is desirable that the pad structure be incorporated directly into the strap. Reasons for this include the attractiveness of the garment itself, the provision of a smooth outer appearance for the wearer's clothes and, as mentioned above, the fact that separate pads can become lost or misplaced.
Further problems are presented by padded straps having sewn in layers of padding. In such straps there is a tendency for the layers to wear and wash differently, causing the strap to bunch and the layers to separate over time. Even if such wear and bunching does not lead to a loss of function of the strap, it does degrade the appearance sufficiently to make the garment in which it is included visually unattractive. Another detriment to known pads and padded straps is the presence of seams, which present either an unattractive outer appearance or an irritant to the skin when turned inward. Further, straps with hollow portions that enclose cushioning materials can be difficult to manufacture, and can split open, possibly allowing leakage of the cushioning material and loss of shape.
Thus, there continues to be a need in the art for a brassiere strap that cushions the shoulder of a wearer to reduce discomfort.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a cushioning laminate insert for a garment shoulder strap, which alleviates the discomfort and depressions formed in a wearer's shoulder while wearing such a garment.
It is also an object of the invention that a garment shoulder strap including the cushioning laminate insert provides a smooth and attractive outer appearance, free of seams, wrinkles or bunching even after extended use, including repeated washings.
Another object of the present invention is to provide a method for making such a cushioning laminate insert for a garment shoulder strap, as well as a garment shoulder strap that include such a cushioning laminate insert.
In one aspect of the invention, the cushioning laminate insert for a garment shoulder strap is provided, which insert comprises: (1) a first outer fabric layer; (2) a central cushioning area of cured polyurethane elastomer cushioning material; and (3) a second outer fabric layer. One surface of the first and second outer fabric layers is laminated with a thermoplastic urethane (“TPU”) film. The laminated surface of the first outer fabric layer is covalently bonded to a first lateral surface of the central cushioning area, and the opposite lateral surface of the central cushioning area is self-adhered to the laminated surface of the second outer fabric layer in an open-sandwich configuration to thereby form the cushioning laminate insert.
In another aspect of the invention, a garment shoulder strap including such a cushioning laminate insert is provided. More particularly, a garment shoulder strap of the invention includes a cushioning laminate insert according to the invention integrated along the length of the strap. The cushioning laminate insert may be positioned along the strap so as to rest the central cushioning area of the insert on top of a shoulder of a wearer to thereby provide cushioning to a wearer and relieve shoulder discomfort.
In yet another aspect of the invention, a method for making such cushioning laminate inserts is provided, which method comprises: (1) providing a molding die with at least one molding cavity lined with a thermoformed polyolefin liner along its surface; (2) casting a polyurethane elastomer material into the lined molding cavity; (3) positioning a first TPU fabric layer over the molding cavity cast with the polyurethane elastomer material with the laminated surface of the fabric adjacent the polyurethane elastomer material; (4) molding the polyurethane elastomer material such that the polyurethane elastomer material is semi-cured and a covalent bond is formed between the semi-cured polyurethane elastomer and the TPU film of the first fabric layer; (5) removing the semi-cured polyurethane elastomer covalently bonded to the first fabric layer from the molding die without the use of a mold release agent; (6) positioning a second TPU fabric layer adjacent the lateral surface of the semi-cured polyurethane elastomer opposite the first fabric layer to form a sandwich construction; (7) applying pressure to the outer surface of the second fabric layer such that the semi-cured polyurethane elastomer self-adheres to the second fabric layer as the polyurethane elastomer continues to cure; and (8) cutting the first and second fabric layers to a desired shape to thereby form the cushioning laminate insert for a brassiere strap.
These and other aspects of the invention will be apparent to one of skill in art upon considering the contents of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1A and B are a top view and side view, respectively, of a cushioning laminate insert for a garment shoulder strap according to the present invention.
FIG. 2 illustrates a brassiere employing a cushioning shoulder strap according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1A and 1B, in one aspect, the cushioning laminate insert 10 of the invention comprises outer periphery edges 11 and a central cushioning area 12. In a preferred embodiment, the insert 10 is configured as a laminate, open sandwich-type construction (shown in FIG. 1B). A first outer fabric layer 13 and a second outer fabric layer 14 are adjacent opposite lateral surfaces of the central cushioning area 12 which comprises a cured polyurethane elastomer 15. One surface of the first and second outer fabric layers 13, 14 is laminated with a thermoplastic urethane (“TPU”) film. The TPU film of the first outer fabric layer 13 is covalently bonded to a lateral surface of the cured polyurethane elastomer 15 of the central cushioning area 12. The opposite lateral surface of the cured polyurethane elastomer 15 of the central cushioning area 12 is self-adhered to the TPU film of the second outer fabric layer 14. In a preferred embodiment, the second outer fabric layer 14 is self-adhered to the cured polyurethane elastomer 15 of the central cushioning area 12 by virtue of the inherent tackiness of the polyurethane elastomer during production, without the need for additional adhesive or heat fusing.
In this manner, the first and second outer fabric layers 13, 14 and the cured polyurethane elastomer 15 form a cushioning laminate insert 10 of a sandwich configuration. With reference to FIGS. 1A and 1B, the peripheral edges 11 of the first and second outer fabric layers 13, 14 preferably do not enclose the vertical edges of the cured polyurethane elastomer 15 such that the cushioning laminate insert is comprised of an open-sandwich configuration.
The cushioning laminate insert of the invention may be straight or curvilinear in shape, depending on the desired end-use product and desired appearance. The central cushioning area of the cushioning laminate insert preferably ranges from about 0.25 inches to about 1 inch, more preferably from about 0.38 inches to about 0.78 inches in width. The overall width of the cushioning laminate insert (including the periphery edges and central cushioning area) preferably ranges from about 0.35 inches to about 1.5 inches in width. Additionally, the cured polyurethane elastomer 15 of central cushioning area 12 is preferably from about 0.05 inches to about 0.30 inches, more preferably from about 0.10 to about 0.20 inches in thickness (illustrated as “a” in FIG. 1B).
In a preferred embodiment, as shown in FIG. 1A, the central cushioning area 12 exhibits a curved shape that ranges from about 0.25 inches at the ends to about 1 inch at the center, more preferably from about 0.38 inches at the ends to about 0.78 inches at the center (illustrated as “b1” and “b2” in FIG. 1A, respectively). The overall width of the cushioning laminate insert 10 (including periphery edges 11 and central cushioning area 12) preferably ranges from about 0.35 inches to about 1.50 inches, more preferably from about 0.50 inches to about 1.33 inches in width. In a particularly preferred embodiment, as shown in FIG. 1A, the cushioning laminate insert 10 exhibits a curved shape that ranges from about 0.45 inches at the ends to about 1.5 inches at the center, more preferably from about 0.50 inches at the ends to about 1.33 inches at the center (illustrated as “c1” and “c2” in FIG. 1A, respectively).
The cushioning laminate inserts of the invention, and garment shoulder strap including such inserts, may be formed from a wide variety of fabrics and polyurethane elastomer materials which are suitable for the molding process described herein and compatible with each other for the purposes described herein. Other than the general suitability for the molding process as described, important factors are the desired final appearance, strength and wear resistance, as recognized by one of ordinary skill in the art.
For reasons of clarity, the first and second outer fabric layers are shown in the figures as each comprising only a single layer. However, it is to be understood that the first and second outer fabric layers 20, 30 are each formed of multiple laminate layers to provide particular desired qualities. For instance, as described above, each outer fabric layer may be comprised of a laminated TPU fabric. Further, each outer fabric layer may further comprise additional laminate layers of fabrics and/or films to provide particular desired qualities, as is known in the art.
In any event, the first and second outer fabric layers preferably comprise any fabric known in the art for production of brassiere straps which possess the desired heat resistance, shiny appearance, strength, wear resistance and elastic memory. The fabrics of the first and second outer fabric layers may be the same or different. Again, a person skilled in the art could identify many different fabrics, for example, various laces, polyester fabrics, and plain or simplex tricot, which would be suitable for use with the present invention. Preferred fabrics include, but are not limited to: cotton, polyester, nylon, nylon-lycra blend fabric, a polyester-cotton blend, laces, plain or simplex tricot, jacquard, spacer fabric, etc. The fabric is preferably laminated on one surface with a TPU film, preferably of soft durometer. The TPU film may preferably range from about 0.5 mil to about 2 mil in thickness.
Preferred polyurethane elastomer materials include any such materials known in the art which are capable of being semi-cured to achieve the desired properties described herein and which are compatible with the TPU film of the first and second outer fabric layers. More particularly, the polyurethane elastomer material is preferably capable of forming a covalent bond with the TPU film of the first outer fabric layer under the molding/curing conditions employed. Further, the polyurethane elastomer material is preferably capable of exhibiting a durometer hardness ranging from about 5 shore 00 to 30 shore 00, more preferably from about 10 shore 00 to about 25 shore 00 when semi-cured under the molding/curing conditions employed. The polyurethane elastomer material is also preferably capable of exhibiting a tackiness sufficient to allow for the self-adhesion of the second outer fabric layer. In a preferred embodiment, the polyurethane elastomer material exhibits a tackiness sufficient to adhere the second outer fabric layer and hold it in position during handling, transportation and storage. By way of example, preferred polyurethane elastomer materials include: ester-polyurethane, ether-based polyurethanes such as ATP C0432-02-3000 (ATP USA Manufacturing, LLC; Rhode Island, USA).
In another aspect, a cushioning garment shoulder strap of the invention comprises a cushioning laminate insert 10. The cushioning laminate insert 10 may be integrated into the brassiere strap in any manner known in the art. For instance, the cushioning laminate insert 10 may be sewn into the strap at a desired location such that central cushion area 12 is positioned along the strap so as to lie adjacent the top of the shoulder of a wearer to thereby provide the cushioning necessary to spread the load and prevent the strap from cutting into the wearer's shoulder.
By way of example, FIG. 2 illustrates a brassiere 24 having cushioning laminate inserts 10 directly sewn into the garment. As is well known, cups 26 directly support the breasts and back strap 28 assists in holding the cups in place. This arrangement is generally incorporated into any garment that includes support for the breasts. However, in some garments, for example swim suits, the function of the back strap may be assumed by the garment itself.
In one embodiment of the invention, the periphery edges 11 of cushioning laminate inserts 10 are directly secured to cups 26 at seams 30, and form the load bearing straps of the garment. Adjustable attachments may be provided at the front or back of the strap. The location of the central cushioning area 12 on the inner side of the garment is indicated in dashed lines. Such a construction provides further advantages over prior art pads which had to be separately attached and therefore could slip out of place or be lost when the garment was not in use. Additionally, this construction allows cushioning laminate inserts 10 to be easily and attractively incorporated into other types of garments that include support for the breast, such as, but not limited to, swim suits, halter tops, athletic wear, slips, camisoles, yoga wear, daywear, and sportswear.
Alternatively, if desired, cushioning laminate inserts of the invention 10 may be fitted at the ends with hooks, loops or other suitable fastening devices to allow the strap to be separately attached to a conventional brassiere strap.
In yet another aspect of the invention, a method for making such cushioning laminate inserts is provided, which method comprises: (1) providing a molding die with at least one molding cavity lined with a thermoformed polyolefin liner along its surface; (2) casting a polyurethane elastomer material into the lined molding cavity; (3) positioning a first TPU fabric layer over the molding cavity cast with the polyurethane elastomer material with the laminated surface of the fabric adjacent the polyurethane elastomer material; (4) molding the polyurethane elastomer material such that the polyurethane elastomer material is semi-cured and a covalent bond is formed between the semi-cured polyurethane elastomer and the TPU film of the first fabric layer; (5) removing the semi-cured polyurethane elastomer covalently bonded to the first fabric layer from the molding die without the use of a mold release agent; (6) positioning a second TPU fabric layer adjacent the lateral surface of the semi-cured polyurethane elastomer opposite the first fabric layer to form a sandwich construction; (7) applying pressure to the outer surface of the second fabric layer such that the semi-cured polyurethane elastomer self-adheres to the second fabric layer as the polyurethane elastomer continues to cure; and (8) cutting the first and second fabric layers to a desired shape to thereby form the cushioning laminate insert for a brassiere strap.
In a preferred embodiment, polyurethane elastomer material is cured in any manner known in the art, including through catalytic/chemical curing and through heat curing. In a preferred embodiment, the polyurethane elastomer is chemically cured by mixing a prepolymer, such as a polyether isocyanate, with a resin, such as a polyol, agitating the mixture, and allowing the starting materials to cure for curing time ranging from about 5 minutes to about 10 minutes, more preferably from about 6 minutes to about 8 minutes. The starting materials may be mixed and agitated in any manner known in the art, such as combining the starting materials in a mixing head and mechanically agitating the materials prior to casting the mixture in the mold.
Because the preferred method of the invention begins with providing a first fabric layer, molding the semi-cured polyolefin elastomer material of the central cushioning area directly to the first fabric layer, and post applying the second fabric layer to the semi-cured polyolefin elastomer as it continues to cure, there is no need for any post molding of the insert. Further, the method of the present invention utilizes polyolefin liners on the mold that allow for molding of the central cushioning area to the first fabric layer without the use of mold release agents. Using mold release agents would severely compromise the self-adhesion of the second fabric layer to the semi-cured polyurethane elastomer, and could result in dislodging of the second fabric layer from the semi-cured polyurethane elastomer during post-molding handling.
More particularly, the polyolefin liner may be created by machining a vacuum form master tool. Generally aluminum, these tools may be designed in CAD then may be cut using CNC machining equipment. Thin sheets of a polyolefin materials, such as polypropylene or polyethylene, may then be thermoformed. The “liners” become a replaceable mold surface into which the polyurethane elastomer material may be cast.
In one embodiment, the mold and polyolefin liners may be designed to have six cavities of a desired, predefined shape, which may be aligned and evenly spaced to allow for alignment in a registered mixhead system, as is known in the art. For instance, in a registered mixhead system, the lined mold die may be initially indexed, and 3 mixheads may cast the first three cavities. A conveyor may re-index the lined mold die, and the mixheads may then cast the second three cavities. The first fabric layer may then be pinned to the cast mold die including the six cavities, and a flat mold lid may be closed on top of the first fabric layer. The conveyor then may pass the closed mold to a molding oven for a desired curing time, during which time the polyurethane elastomer is semi-cured and the first fabric layer is covalently bonded to the semi-cured polyurethane elastomer. After the desired curing time, the conveyor may present an open mold to an operator. The operator may then strip out the first fabric layer with the six semi-cured polyurethane elastomer forms covalently bonded thereto. Because no mold release agent is present in the process and the polyurethane elastomer is semi-cured, the operator may then simply position the second fabric layer on top of the exposed side of the six semi-cured polyurethane elastomer forms, and press down to self-adhere the second fabric layer to the semi-cured polyurethane elastomer in a sandwich configuration. If mold release agent was present, the second fabric layer may not adequately self-adhere. The polyurethane elastomer will continue to cure during final production until it reaches a final cure state.
Once assembled into the sandwich configuration, the molded set may progress up a take-away conveyor to a die-cutting operation, where the pre-cut laminates may be indexed into the hydraulic cutting station and die cut to the desired shape. According to the method of the invention, no hollow portion is created and no edges are sealed. The method involves molding a defined semi-cured polyurethane elastomer to a first fabric layer to form a covalent bond, and due to the molding techniques, a second fabric layer may be self-adhered with sufficient bond for the post handling, transit and final assembly process. Once the first fabric layer is covalently bonded and the second fabric layer is self-adhered, the polyurethane elastomer will continue to cure until it reaches a state of final cure.
The present invention having been described with particular reference to the preferred embodiments thereof, it is understood that various changes and modification may be made without departing from the spirit and scope of the invention, as defined in the appended claims.

Claims

1. A cushioning laminate insert for a garment shoulder strap, comprising:

a first outer fabric layer;

a central cushioning area of cured polyurethane elastomer cushioning material; and

a second outer fabric layer;

wherein one surface of the first and second outer fabric layers is laminated with a thermoplastic urethane film;

wherein the laminated surface of the first outer fabric layer is adjacent a first lateral surface of the central cushioning area, and the laminated surface of the second outer fabric layer is adjacent the opposite lateral surface of the central cushioning area to thereby form a sandwich construction; and

wherein the first outer fabric layer is covalently bonded to the first lateral surface of the central cushioning area, and the second outer fabric layer is self-adhered to the opposite lateral surface of the central cushioning area to thereby form a cushioning laminate insert for a garment shoulder strap.

2. The cushioning laminate insert according to claim 1, wherein the second outer fabric layer is self-adhered to the central cushioning area without the need for additional adhesive or heat fusing.

3. The cushioning laminate insert according to claim 1, wherein the first and second outer fabric layers do not enclose the vertical edges of the central cushioning area such that the cushioning laminate insert is comprised of an open sandwich configuration.

4. The cushioning laminate insert according to claim 1, wherein the first and second outer fabric layers comprise a fabric selected from the group consisting of: cotton, polyester, nylon, nylon-lycra blend fabric, a polyester-cotton blend, lace, plain tricot, simplex tricot, and jacquard.

5. The cushioning laminate insert according to claim 1, wherein the polyurethane elastomer is an ether polyurethane.

6. The cushioning laminate insert according to claim 1, wherein the central cushioning area is from about 0.05 inches to about 0.30 inches in thickness.

7. The cushioning laminate insert according to claim 1, wherein the central cushioning area is from about 0.10 inches to about 0.20 inches in thickness.

8. The cushioning laminate insert according to claim 1, wherein the semi-cured polyurethane elastomer cushioning material exhibits a durometer hardness ranging from about 10 shore 00 to about 30 shore 00.

9. The cushioning laminate insert according to claim 1, wherein the cured polyurethane elastomer cushioning material exhibits a tackiness sufficient to adhere the second outer fabric layer to the cured polyurethane elastomer.

10. A cushioning shoulder strap for a garment comprising: a cushioning laminate insert according to claim 1, wherein the central cushioning area of the cushioning laminate insert is positioned along the strap so as to rest on top of a shoulder of a wearer.

11. The cushioning shoulder strap of claim 1, wherein the garment is selected from the group consisting of: a brassiere, a swim suit, a halter top, athletic wear, a camisole, yoga wear, daywear, and sportswear.

12. A method for making a cushioning laminate insert for a garment shoulder strap, comprising:

providing a mold die comprising at least one molding cavity, wherein the at least one molding cavity is lined with a thermoformed polyolefin liner along its surface;

casting a polyurethane elastomer material into the at least one lined molding cavity;

positioning a first fabric layer over the at least one lined molding cavity cast with the polyurethane elastomer material, wherein the surface of the first fabric layer that is adjacent the polyurethane elastomer material is laminated with a thermoplastic urethane film;

molding the polyurethane elastomer material such that the polyurethane elastomer material is semi-cured and a covalent bond is formed between the semi-cured polyurethane elastomer and the thermoplastic urethane film of the first fabric layer;

removing the semi-cured polyurethane elastomer covalently bonded to the first fabric layer from the molding die without the use of a mold release agent;

positioning a second fabric layer adjacent the lateral surface of the semi-cured polyurethane elastomer opposite the first fabric layer to form a sandwich construction;

applying pressure to the outer surface of the second fabric layer such that the semi-cured polyurethane elastomer self-adheres to the second fabric layer as the polyurethane elastomer continues to cure; and

cutting the first and second fabric layers to a desired shape to thereby form the cushioning laminate insert for a brassiere strap.

13. The method according to claim 12, wherein the first and second fabric layers do not enclose the vertical edges of the semi-cured polyurethane elastomer such that the cushioning laminate insert is comprised of an open sandwich configuration.

14. The method according to claim 12, wherein the molding of the polyurethane elastomer material includes: (a) mixing a polyether isocyanate prepolymer with a polyol resin, and (b) allowing the mixture to cure for a curing time ranging from about 5 minutes to about 10 minutes.

15. The method according to claim 14, wherein the curing time ranges from about 6 minutes to about 8 minutes.

16. A cushioning shoulder strap for a brassiere including a cushioning laminate insert;

wherein the cushioning laminate insert comprises: a first outer fabric layer; a central cushioning area of cured polyurethane elastomer cushioning material; and a second outer fabric layer;

wherein the laminated surface of the first outer fabric layer is adjacent a first lateral surface of the central cushioning area, and the laminated surface of the second outer fabric layer is adjacent the opposite lateral surface of the central cushioning area to thereby form a sandwich construction;

wherein the first outer fabric layer is covalently bonded to the first lateral surface of the central cushioning area, and the second outer fabric layer is self-adhered to the opposite lateral surface of the central cushioning area to thereby form a cushioning laminate insert, and

wherein the central cushioning area of the cushioning laminate insert is positioned along the strap so as to rest on top of a shoulder of a wearer.