WATERPROOF, BREATHABLE ARTICLES OF APPAREL

Abstract: A footwear article and the method of making the same which will allow water vapor due to perspiration to transpire through the article but will prevent liquid water from external sources from reaching the wearer's foot. One form of the footwear article of the invention comprises a sock which is of three-ply construction with the inside (20) and outside (22) plies being knit and the intermediate ply (14) being made from an elastomeric polyurethane film. The three plies (14, 20 and 22) are uniquely bonded together using a pliant, waterproof adhesive.

Description: WATERPROOF, BREATHABLE ARTICLES OF APPAREL S P E C I F I C A T I O N Background of the Invention Field of the Invention The present invention relates generally to articles of apparel. More particularly, the invention concerns articles of apparel used to cover the wearer's extremities such as an im¬ proved, waterproof sock that will permit perspiration to tran¬ spire through the sock, but will keep water from external sources away from the wearer's foot- Discussion of the Invention Various attempts have been made in the past to produce breathable, waterproof articles of apparel such as gloves and socks that will keep the wearer's hands and feet dry and at the same time permit perspiration to transpire through the article. Materials which will accomplish this desired function have been known for sometime. For example, U.S. Patent No. 3,953,566 discloses a method of making an expanded polytetrafluoroethy- lene (PTFE) that possesses the properties of being both breath¬ able and waterproof. An improvement of this material is de¬ scribed in U.S. Patent No. 4,194,041. While both of these materials have been used in the construction of footwear, they exhibit the drawback that they have limited stretchability, thereby making them less than ideally suited for construction of footwear such as socks. In addition, such footwear typical¬ ly has sewn seems and tapes which make it bulky and uncomfort¬ able. In an apparent attempt to overcome the problems discussed in the preceding paragraph, a multi-component sock type article was suggested. This article, which is described in U.S. Patent SUBSTITUTESHE No. 4,819,447 issued to Pacanowsky, et al. , comprises a water¬ proof, nonelastic, non-stretch sole component, a non-stretch calf component and a vamp component attached to the sole and calf components. As will be better appreciated from the discussion which follows, the footwear article of the present invention provides, for the first time, footwear such as socks construc¬ tion which exhibit the comfort and stretchability of a tradi¬ tional type of sport sock and at the same time are both breath¬ able and completely waterproof. Summary of the Invention It is an object of the present invention to provide com¬ fortable articles of apparel and the method of making the same which will allow water vapor due to perspiration to transpire through the article but will prevent water from external sourc¬ es from reaching the wearer's extremities. A particular object of the invention is to provide a foot¬ wear article of the aforementioned character which fits well, is pliant and is durable in use. Another object of the invention is to provide an article such as a glove or sock in which water vapor from perspiration can be transmitted from inside to outside so that the natural evaporative cooling effect can be achieved. Another object of the invention is to provide a method of making articles of the character described in the preceding paragraphs which is simple and straight forward, does not require the use of complicated equipment such as sewing and seaming equipment and can be performed by unskilled workmen with a minimum of training. A particular object of the invention is to provide a sock as described in the preceding paragraphs which is of simple SUBSTITUTE SHEET construction and is easy to manufacture. In its preferred form, the footwear article of the inven¬ tion comprises a sock which is of three-ply construction with the inside and outside plies being knit and the intermediate ply being made from an elastomeric polyurethane film. The three-plies are uniquely bonded together using a pliant, water¬ proof adhesive. Brief Description of the Drawings Figure 1 is a side-elevational view illustrating the method of making the footwear article of the invention and showing the components of the article in position over a foot- shaped planar mandrel. Figure 2 is an enlarged cross-sectional view taken along lines 2-2 of Figure 1. Figure 3 is a side-elevational view of one form of the footwear article of the invention. Figure 4 is an enlarged cross-sectional view taken along lines 4-4 of Figure 3. Description of the Invention In the description which follows: The term "breathable" means the ability of an article to transport interior moisture vapor to the external environment. As used herein, the term "waterproof" means the ability of an article to substantially prevent liquid water from external sources from reaching the interior of the article. Similarly, the term "fabric" as used herein means a sheet structure made from fibers, filaments or yarns. Non-limiting examples include woven or nonwoven sheets made by weaving, knitting, felting, hydroentangling or meltblowing fibers, filaments or yarns. The term "sock" as used herein means a short, close-fit- SUBSTITUTESHEET ting covering for the foot and lower leg constructed from any suitable material such as natural and synthetic fibers. Referring to the drawings, Figures 3 and 4 show one form of the clothing article of the present invention. The article here comprises a sock construction including a thin, pliant bladder 14 constructed from a waterproof, breathable material, such as polyurethane sheet. The polyurethane sheet can be of various thickness as, for example, between about 0.5 mils and about 3 mils. Bladder 12 includes a foot portion 14 having an outer surface 16 and an inner surface 18. Bladder 12 has the unique capability of generally conforming to the contours of the human foot so that it can be comfortably worn inside a boot or shoe. Bonded to the inner surface 18 of the elastomeric bladder is a light-weight covering member such as a fabric inner sock 20 of standard construction which is preferably made from knitted natural or synthetic fibers. The article of the invention shown in Figure 3 also in¬ cludes an outer sock 22 which is bonded to the outer surface of bladder 14. Sock 22 can also be constructed from filament or spun yarns. The sock can also be constructed from natural fibers; such as wool fibers, or from a variety of synthetic fibers such as polyester nylon and combinations thereof. Socks 20 and 22 are preferably bonded to bladder 14 by means of a waterproof, heat activated adhesive. A hot melt adhesive in powder form sold by Bostik, Middleton, Massachu¬ setts, product #5116, a polyester type, has proven satisfactory for this purpose. Other adhesives can, of course, also be used, including breathable adhesives. In any event, the adhe¬ sive should be selected and applied in a manner that the breathability of the footwear is not destroyed or substantially SUBSTITUTE SHEET reduced. For certain applications the footwear article of the invention can be constructed by bonding to the bladder only a single inner or outer sock. This two, rather than three-ply construction, can be used in a number of applications in which the three or more ply constructions are too bulky or too expen¬ sive. The thin pliant, thermoplastic material from which the waterproof, breathable bladder will be made is of a character that will prevent penetration of liquid water while at the same time permitting free passage of moisture vapor such as perspi¬ ration. This material can be a polyurethane sometimes de¬ scribed as thermoplastic urethane. A suitable material of this type is sold by Fabrite Laminating Corp. of Woodridge, New Jersey. Other suitable materials include elastomers made from polyesters, co-polyesters, polyamides, ' cellulose derivatives, polyacrylic acid and its holologε, natural or synthetic rubber with hydrophilic impurities, copolyozamides, polyureas, poly- electrolytes, polyphosphates, polyvinylamid, polyvinylalcohol, polyether, and copolymers thereof, polythioether, polythioeth- er-polyether, copolyepichlorohydrin-ether, polysulphosphates, copolyester-ether and derivatives or mixtures thereof. Considering now the method of the invention, the thin, pliant bladder material is first coated with a light coating of the powdered hot melt adhesive, Bostik #5116. The adhesive particles randomly cover the bladder evenly to a density of about 20% coverage of the surface area. This bladder material with adhesive is then heated to a temperature slightly above the softening point of the adhesive, thereby causing the dis¬ crete particles of adhesive to fuse to the surface of the bladder material. In the case of Bostik #5116, the softening SUBSTITUTE SHEET point is 268 degrees Fahrenheit. This means is also used to coat particles of adhesive on both sides of the bladder materi¬ al. The next step is the construction of the waterproof, breathable bladder. In one form of the method of the invention this is accomplished by overlaying two sheets of the previously described adhesive coated bladder material and to define on the sheets of material a line circumscribing the boundary of the bladder. This done, the sheets of material are heated along the boundary line to a temperature sufficient to sealably bond the sheets together along the boundary line. The heating-fusion step can be accomplished in several ways well known to those skilled in the art, including using a heated wire or die having the shape of the bladder-boundary. Heating can also be accomplished through the use of well-known radio frequency and ultrasonic welding techniques. One technique which has proven to be satisfactory in making the footwear of the invention, involves the use of a heated platen press embodying a die having the shape of the outer boundary of the bladders. The die is electrically heated to about 500 degrees Fahrenheit. One of the cooperating pla¬ tens of the platen press is maintained at room temperature and, is lined with a flexible fabric such as felt. The two sheets of the adhesive-coated bladder material are placed between two sheets of polytetrafluoroethylene coated fiber glass sheets which act as separator material and also allow the heat from the die to penetrate to the film. Appropriate heating of the dies causes the sheets of bladder material to be effectively welded, or sealably joined together along the boundary line to make the sock-shaped bladder. After the welding process, the excess material outside the bladder boundary is manually SUBSTITUTE SHEET stripped away and the bladder is removed from the platen press. By these means, a sock-shaped bladder component with discrete particles of hot melt adhesive both inside and outside has been produced. It is to be noted that the proper application of the adhe¬ sive to the inner and outer surfaces of the bladder is critical to the success of the manufacturing process, since, when com¬ pleted, the sock must be breathable, flexible, pliant and waterproof and it must withstand laundering and physical abuse while being worn. It is to be noted that the adhesives can also be applied to the fabric components as an alternative means of construction. As illustrated in Figures 1 and 2 of the drawings, the next step in the process of the invention is to place the first covering member, or inner sock 20 over a generally foot-shaped, approximately l/8th inch thick, generally planer mandrel 27. Sock 20, which has inner and outer surfaces 20a and 20b is placed over the mandrel so that inner surface 20a thereof is disposed in engagement with the faces 27a of mandrel 27. As previously discussed, sock 20 can be constructed from a variety of materials. However, a sock which is made by Wigwam Mills, Inc. of Sheboygan, Wisconsin special knit pattern of its stan¬ dard BK-1188 has proven satisfactory. An alternate inner sock, also made by Wigwam, is intended to impart cold weather comfort to the waterproof footwear article of the present invention depending on the climate encountered. For cold weather com¬ fort, the inner sock can be made utilizing Thermax R made by E. I. duPont de Nemours and Co. of Wilmington, Delaware. For warm weather comfort the inner sock can be made utilizing Coolmax R made by duPont. After sock 20 has been placed over mandrel 27 and smoothed SUBSTITUTE SHEET out so that its inner surface is in close engagement with the faces of the mandrel 27, the bladder 12, which has been adhe¬ sive coated with particles of hot melt adhesive inside and outside is carefully placed over the assemblage of sock 20 and mandrel 27. The bladder is smoothed to be in close engagement with the outer surface of sock 20. Outer sock 22 is placed over both the inner sock 20 and the adhesive coated bladder assemblage on mandrel 27. The precursor assembly comprising first sock 20, the adhe¬ sive coated bladder 12 and the second sock 22 is then heated and compressed in the direction of the arrows 34 in Figure 2 to form the finished article. This step is accomplished by plac¬ ing the mandrel, upon which the precursor assembly is mounted, between two platens which can be controllably heated and urged together. More particularly, the platens are preferably elec¬ trically heated to a temperature of about 280 degrees Fahren¬ heit and are controllably moved into pressural engagement with the precursor assembly by any type of hydraulically actuated pressure imparting assembly of a character well known to those skilled in the art. A commercially available press suitable for carrying out the method of the invention is sold by PHI of the City of Industry, California. During this temperature- pressure step, the heat activated adhesive is thereby fused making a permanent, water resistant bond of inner sock 20 to one side of the bladder and the outer sock 22 to the other side of the bladder. The minimum temperature required to activate the Bostik #5116 adhesive is 268 degrees Fahrenheit. Accord¬ ingly, a temperature range of between about 270 degrees Fahren¬ heit and 290 degrees Fahrenheit is preferred. The precursor assembly is then removed from the press and allowed to cool thoroughly prior to doffing the completed SUBSTITUTESHEET waterproof footwear article from the mandrel. When removed from the mandrel, the footwear article is generally planar in shape. However, upon inserting the foot into the open cuff of the article, the foot engaging portion of the sock will neatly and smoothly conform to the shape of the wearer's foot. Depending upon the end use of the article, other commer¬ cially available adhesives can also be used in the practice of the method of the invention. By way of example, these include an adhesive sold by Stahl U.S.A. of Peabody, Massachusetts under the designation UE-4172 and an adhesive sold by Reichhold Chemicals, Inc. under the product code EA 6494. Further, a mixture of the Reichhold EA 6494 and a SOLUCOTE R 1024 adhesive made by Soluol Chemical Co. , Inc. can be used for some end product applications. When the adhesive used is in liquid form it can be sprayed, brushed or otherwise applied to the elastomeric blad¬ der or sock fabric. As previously stated when the adhesive is applied to the bladder it must be applied in the manner, such as a dot matrix coating, which will not degrade the breathabil¬ ity characteristics of the bladder material. It is to be understood that the method of the invention can be used to produce various articles of clothing such as socks and gloves. Such articles can be made in various sizes and design configurations to fit a wide variety of users. Having now described the invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difficulty in making changes and modifi¬ cations in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such chang¬ es and modifications may be made without departing from the SUBSTITUTESHEET scope and spirit of the invention, as set forth in the follow¬ ing claims. SUBSTITUTESHEET

Claims: I CLAIM 1. A method of making an article of apparel used to cover a wearer's extremities comprising the steps of: (a) forming a waterproof, breathable material into a bladder having an open cuff portion and an extremity receiving portion including an outer surface and in inner surface generally conformable to the contours of the extremity to be covered; and (b) bonding a first covering member to said inner surface of said extremity receiving portion of said blad¬ der to form a subassembly portion of said article. 2. A method as defined in Claim 1 including the further step of bonding a second covering member to said outer surface of said extremity receiving portion of said bladder to form a precursor article. 3. A method as defined in Claim 1 in which said water¬ proof, breathable material comprises a thin film. 4. A method as defined in Claim 3 in which said thin film comprises urethane. 5. A method as defined in Claim 3 in which said first covering member is bonded to said inner surface of said extrem¬ ity receiving portion of said bladder using a waterproof adhe¬ sive. 6. A method as defined in Claim 3 in which said first covering member is bonded to said inner surface of said extrem¬ ity receiving portion of said bladder using a heat activated adhesive. 7. A method as defined in Claim 6 including the further step of heating said subassembly. 8. A method as defined in Claim 7 in which said subas- SUBSTITUTESHEET sembly is heated to a temperature of between approximately 280 degrees F and 310 degrees F. 9. A method as defined in Claim 7 including the further step of compressing said subassembly during heating. 10. A method of making a waterproof footwear article con¬ structed of an inner fabric sock, an outer fabric sock and an intermediate pliant, waterproof, breathable bladder comprising the steps of: (a) applying a thin layer of heat activated adhesive over the outer surface of the inner fabric sock to form a coated inner sock; (b) placing the bladder over the coated inner sock to form a subassembly; (c) applying a thin layer of adhesive over the inner surface of the outer fabric sock to form a coated outer sock; (d) placing said coated outer sock over said subas¬ sembly so that said layer of adhesive is proximate said bladder to form a precursor article; and (e) heating said precursor article to a temperature sufficient to activate said heat adhesive. 11. A method as defined in Claim 10 in which said precur¬ sor article is compressed during said heating step in a manner to urge said inner and outer plies into close proximity with said bladder. 12. A method as defined in Claim 10 in which said adhe¬ sive comprises urethane polymer and in which said assembly is heated to a temperature sufficient to cross link said urethane polymer. 13. A method as defined in Claim 12 in which said assem¬ bly is heated to a temperature of approximately 300 degrees SUBSTITUTESHEET Fahrenheit. 14. A method as defined in Claim 12 in which said bladder comprises a thin, elastomeric polyurethane film. 15. A method as defined in Claim 14 in which said first and second socks comprise yarns made of fibers. 16. A method as defined in Claim 14 in which said first and second socks comprise a material selected from the group consisting of nylon, polyester and combinations thereof. 17. A method of making an article of footwear comprising the steps of: (a) constructing a waterproof, breathable, elasto¬ meric bladder having a foot receiving portion including an outer surface and an inner surface having the ability to generally conform to the contour of a human foot compris¬ ing the steps of: (i) overlaying two thin sheets of thermo plas¬ tic material of a character that will prevent pene¬ tration of liquid water while at the same time per¬ mitting free passage of moisture vapor such as that resulting from perspiration; (ii) defining on said sheets of material a line circumscribing the boundary of said elastomeric blad¬ der; (iii) heating said sheets of material along said boundary line to a temperature sufficient to sealably bond said sheets together along said boundary line; and (iv) removing from said sheets excess material located externally of said boundary line; (b) placing a first fabric sock having first and second surfaces over a thin generally foot-shaped planar SUBSTITUTE SHEET mandrel with said first surface being located adjacent said mandrel; (c) coating said second surface of said fabric sock with an adhesive to form a coated sock; (d) placing said bladder over said coated sock to form a subassembly; (e) placing a second fabric sock having a first and second surface over a thin, generally foot-shaped planar mandrel with said first surface in engagement with said mandrel; (f) coating said second surface of said second fabric sock with an adhesive; (g) removing said second sock from said mandrel and placing it over said subassembly with said second surface thereof in engagement with said bladder to form a precur¬ sor article; and (h) compressing said precursor article to urge said first and second fabric socks into engagement with said bladder. 18. A method as defined in Claim 17 in which said adhe¬ sive is thermosetting and which includes the further step of heating said precursor article during the compressing step to a temperature sufficient to bond said first and second socks to said bladder. 19. A method as defined in Claim 18 in which said adhe¬ sive is waterproof. 20. A method as defined in Claim 18 in which said bladder comprises a thin polyurethane film. 21. A method as defined in Claim 18 in which said first and second socks comprise knitted fibers. 22. A method as defined in Claim 18 in which said first SUBSTITUTE SHEET and second socks comprise polyester. 23. A method as defined in Claim 18 in which said first and second socks comprise nylon. 24. A method of making a waterproof footwear article con¬ structed of an inner sock, an outer sock and an intermediate pliant, waterproof, breathable bladder having first and second surfaces, said method comprising the steps of: (a) applying adhesive onto the first surface of the bladder to form a coated bladder; (b) placing the outer sock over the coated bladder to form a subassembly; (c) turning said subassembly inside out to expose the second surface of the bladder; (d) applying adhesive to the second surface of the bladder; (e) placing the inner sock over said subassembly so that said adhesive is proximate said inner sock to form a precursor article; and (f) heating said precursor article to a temperature sufficient to securely bond together said bladder and said socks. 25. A method as defined in Claim 24 in which the adhesive is in powder form and is applied to said bladder in a manner to provide a multiplicity of adhesive particles on said first and second surfaces of said bladder. 26. A method as defined in Claim 24 in which said adhe¬ sive is a waterproof, hot meld powder adhesive and said precur¬ sor compressed during said heating step in a manner to urge said inner and outer socks into close proximity with said bladder. 27. A method as defined in Claim 26 in which said bladder SUBSTITUTESHEET is polyurethane and in which said assembly is heated to a temperature of between 270 degrees Fahrenheit and 290 degrees Fahrenheit. 28. A method as defined in Claim 27 in which said first and second socks comprise yarns made of fibers. 29. A method as defined in Claim 27 in which said first and second socks comprise synthetic fibers. 30. A method as defined in Claim 27 in which said first and second socks comprise a blend of natural and synthetic fibers. 31. An article of apparel used to cover a wearer's ex¬ tremities comprising: (a) a pliant, generally extremity-shaped hollow bladder constructed from a waterproof, breathable materi¬ al, said bladder having an extremity covering portion, including an outer surface and an inner surface generally conforming to the contours of the extremity; and (b) a generally extremity shaped covering member emplaced in close proximity with and bonded to one of said inner and outer surfaces of said bladder. 32. An article as defined in Claim 31 in which said cover¬ ing member is constructed of yarns made of fibers. 33. An article as defined in Claim 31 in which said covering member is bonded to said bladder by a waterproof, breathable adhesive. 34. An article as defined in Claim 31 in which said covering member is bonded to said bladder by a heat activated adhesive. 35. An article as defined in Claim 31 further including a second covering member bonded to the other side of said inner and outer surfaces of said bladder. SUBSTITUTESHEET 36. An article as defined in Claim 31 in which said article is adapted to cover a wearer's foot and in which said bladder and said first covering member are in the general shape of a human foot. 37. A waterproof footwear article comprising: (a) an elastomeric, breathable and waterproof blad¬ der; and (b) inner and outer fabric socks bonded to said bladder. 38. An article as defined in Claim 37 in which said elastomeric bladder permits the water vapor content of perspi¬ ration to pass therethrough in a direction toward said outer sock, but prevents water in liquid form from passing there¬ through toward said inner sock. 39. An article as defined in Claim 38 in which said bladder comprises a material selected from a group consisting of urethane, polyurethane, and elastomers made from polyester, polyamides, cellulose derivatives and polyacrylic acid. 40. An article as defined in Claim 38 in which said inner and outer socks are bonded to said bladder by a heat activated adhesive. 41. An article as defined in Claim 38 in which said inner and outer socks comprise natural fibers. 42. An article as defined in Claim 38 in which said inner and outer socks comprise synthetic fibers. 43. An article as defined in Claim 38 in which said inner and outer socks comprise a blend of natural and synthetic fibers. ' 44. An article as defined in Claim 38 in which said inner and outer socks comprise nylon fibers. SUBSTITUTE SHEET 18 45. An article as defined in Claim 38 in which said inner and outer socks comprise polyester fibers. 46. A waterproof footwear article comprising: (a) a fabric inner ply; (b) a fabric outer ply; and (c) a pliant intermediate ply comprising a thin, breathable waterproof bladder, said inner and outer plies being bonded to said intermediate ply. 47. An article as defined in Claim 46 in which said inner and outer plies are of knitted, seamless construction. 48. An article as described in Claim 46 in which said bladder comprises a polyurethane film. SUBSTITUTESHEET

Inventors: WILLIAMS COLE, WILLIAMS, COLE
Applicants: WILLIAMS COLE, WILLIAMS, COLE
Application year: 1993
Main classification: A41B11
IPC codes: A41B11, A41B17, A41D19, A41D31, B32B5, B32B7, B32B27