Abstract:
A multilayer compression support sleeve construction. The laminate material includes a thin polyurethane film coated on both surfaces with an adhesive. A stretchable elastomeric polymer material is bonded to each of the adhesive surfaces. A substantial portion of one of the elastomeric polymer surfaces is coated with a discontinuous layer of silicone microdots. The microdots are applied by gravure roll printing to project a uniform distance above the elastomeric polymer surface to form small tacky dots. The laminate material is fabricated into a sleeve with the material oriented so that the microdot coated face is adjacent the skin of the wearer. Microdots may be applied in a predetermined pattern in order to impart enhanced compression to certain areas of the support sleeve. The resulting support sleeve retains its breathability while presenting a nonslip inner surface which prevents migration of the garment on the skin of the wearer during exercise. The garment does not cause irritation to the underlying skin.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention is directed to an improved compression support sleeve constructed to stay comfortably in place during strenuous activity without the need for stays or straps and without causing irritation of the underlying skin. More particularly, it is concerned with a sleeve of laminate multilayer construction having a skin-contacting surface substantially coated with a thin layer of discontinuous silicone microdots. Advantageously, the resulting sleeve construction is freely stretchable to conform to the muscles and joints of a user, while providing slip-resistant support and augmented compression without impairing breathability of the device.  
           [0002]    The upright posture of the human body renders it particularly susceptible to strains, sprains and other injuries which are generally manifested by swelling, inflammation and discomfort. When severe, an injury may result in impaired mobility and necessitate restriction of movement and activity. The body is also subject to formation of fibrin clots which may obstruct vessels in the peripheral circulation when the body is in the prone position for prolonged periods. In addition to localized morbidity, such clots may also break free and travel to the heart or lungs causing more serious damage.  
           [0003]    Orthopedic injuries have economic as well as physical repercussions for professional athletes engaged in competitive sports. Sidelined athletes lose not only the opportunity to perform, but experience a reduction in their overall level of fitness during periods of restricted activity, necessitating a period of retraining prior to resumption of competition. Of course, most individuals are not professional athletes and they engage in less strenuous activities such as jogging, calisthenics, walking and occasional competitive sports.  
           [0004]    However, non professional athletes also experience discomfort when injured and their level of physical fitness is also impaired by injury-enforced inactivity. Moreover, amateur athletes may be more likely to be susceptible to injury, since they generally lack the advice of professional trainers as well as the fitness and judgment developed by professional athletes. Those who engage in infrequent bouts of strenuous exercise without training are most at risk of injury. However, even the well-trained amateur athlete is subject to occasional strains and sprains. Some individuals are particularly at risk of injury because of previous traumatic injury which has left continuing weakness in a joint or limb. Other individuals are at greater risk because of their advanced age or general state of health and fitness.  
           [0005]    The importance of providing compression support to limbs and joints which have been injured or weakened or which are subject to stress, such as may be caused by strenuous exercise, is well recognized. So-called R.I.C.E. therapy (rest, ice, compression, elevation) is commonly recommended for implementation following minor athletic injuries. Such therapy is known to be particularly effective when cold and compression are applied immediately following an injury and the compression is continued for a period of about 24 to 48 hours. The need to provide compression to facilitate venous return in bed bound patients in order to prevent formation of blood clots is similarly well recognized.  
           [0006]    Orthopedic compression bandages, braces and sleeves have long been employed to provide support for athletic and medical purposes. They are commonly worn over the wrists, elbows, knees and ankles. They are also frequently employed on the lower legs and forearms, and, less frequently, on the upper legs and arms, shoulders and chest. They provide support during normal movement, which support may be especially required by persons recovering from previous injuries or by persons who are frail or elderly. Such compression devices also provide support for ligaments, tendons, muscles and joints against the stresses of over extension which may occur during exercise. In this manner, they help to prevent orthopedic and muscular injury or reinjury. Elastomeric sleeves have also been employed, commonly in the form of stockings, to provide compression in order to facilitate peripheral venous return from the legs of bed bound patients, thereby helping to prevent embolism.  
           [0007]    Such compression support devices are often of elastomeric construction, either in the form of sleeves, dressings or strips which may be slipped over or wound around the affected area and fastened by means of hook and loop fasteners or specialized clips or pins.  
           [0008]    A number of materials have been employed in the construction of such support devices. Dressing, strip and sleeve-type supports are generally constructed of knitted or woven elastic webbing consisting of elastic or cotton-wound elastic threads or of stretchable synthetic resin compositions such as neoprene. Laminate multilayer composite materials have recently become available which are thinner than previously used woven elastics and especially neoprene. Such multilayer materials may be fabricated into sleeve or bandage-type supports. They are often five layers thick, with a synthetic resinous film layer sandwiched between two adhesive layers, each of which is covered by an outer layer of a stretchable synthetic fabric such as nylon. However, the skin-contacting layer is quite slick, and the support tends to migrate along the skin unless it is sized and custom fitted to the limb of a wearer. This is especially true of supports placed about the knee as such supports slip or migrate along the leg.  
           [0009]    Known knitted, woven and laminate materials tend to experience slippage along the limb and to wrinkle or bunch up, causing compression of the limb to be uneven. Such shifting and uneven displacement of the material against the skin causes dermal irritation and discomfort to the wearer. Slippage of laminate supports can be limited, but not eliminated by custom fitting. However, such fitting requires personal consultation with a professional fitter. Thus, it is expensive and consequently unavailable to most users. Moreover, changes in body weight, weight distribution or development of musculature because of growth, exercise or aging may necessitate periodic refitting of the brace to maintain proper support.  
           [0010]    Because of these problems, some braces have been constructed of rubber-like polymeric materials such as neoprene, which tends to stay in place because of its high coefficient of friction against the skin. Neoprene supports are generally thicker and bulkier than braces constructed of other materials, and such materials have not proven to be satisfactory for frequent or sustained use because of their lack of permeability to air and water. Supports constructed of neoprene do not permit the underlying skin of the wearer to breathe. Because such impermeable supports lack ventilation to carry away body heat and moisture, extended or frequent wear may be uncomfortable as well as irritating to the skin. If such irritation is prolonged, it can result in morbidity such as dermatitis and sloughing of the skin. Such impermeable materials are especially unsuitable for compression bandages to be worn by amputees or individuals with impaired circulation, who may develop necroses. In addition, since impermeable supports provide no outlet for perspiration excreted by the wearer, a salt residue is deposited on the inner surface of the support which eventually serves to impair elasticity and shorten its effective life span.  
           [0011]    Since braces constructed entirely of impermeable, slip-resistant materials have not proven to be satisfactory, attempts have been made to construct braces from a combination of elastomeric and slip-resistant materials. One current technique is to apply a continuous bead or band of a slip-resistant material such as silicone around the upper inner surface of the support. Certain applications, such as ankle braces, may require bands at both the upper and lower inner surfaces in order to control slippage. However, the slip-resistant material is impermeable, lacks ventilation, and is consequently uncomfortable against the skin of the wearer. Such bands project inwardly against the skin, causing additional compression and discomfort. In addition, because the band is of necessity localized at the top of the support and is fairly narrow, it is not entirely effective in preventing slippage.  
           [0012]    None of the previously available materials and combinations of materials provide effective elastomeric support and compression while staying in place and maintaining breathability for the underlying skin surface. Accordingly, there is a need for a compression support sleeve for athletic and medical uses which is light weight, comfortable, stretchable to conform to the anatomy of a user and to permit movement, which resists shifting against the skin and migration during exercise and which does not impair breathability of the underlying skin or circulation of the underlying blood vessels.  
         SUMMARY OF THE INVENTION  
         [0013]    The present invention resolves the problems previously outlined and provides a greatly improved compression support sleeve which is comfortable, freely stretchable and breathable and is especially designed to stay in place and to minimize skin irritation.  
           [0014]    The support sleeve includes a multilayer laminate material formed into a tube or other compression structure which is constructed to conform in shape to an intended limb or joint. The sleeve may be tailored with gussets or darts to improve the fit, and may be equipped with one or more support stays or pulls to facilitate placing the sleeve on the user. The laminate material includes a polyurethane film having an adhesive coating applied to either side. The adhesive coatings are each bonded to respective layers of a stretchable elastomeric polymer material. The inner elastomeric polymer surface of the sleeve, which faces the skin of the wearer, is substantially coated with a discontinuous layer of silicone microdots. The microdot-imprinted surface remains permanently tacky, serving to prevent slippage of the finished support garment while the spacing between the microdots facilitates “breathing” of the material.  
           [0015]    In particularly preferred forms, the silicone is applied by gravure roll printing during manufacture of the sleeve to provide microdots having a uniform depth. The support may be worn repeatedly and laundered without loss of friction by the silicone-coated surface.  
         Objects and Advantages of the Invention  
         [0016]    The principal objects and advantages of the present invention are: to provide a compression support which stays in place on the body of a wearer while maintaining breathability of the underlying skin; to provide such a support which is of multilayer laminate construction; to provide such a support which is light weight and comfortable to a wearer; to provide such a support which does not irritate the skin of a wearer; to provide such a support which has enhanced compression properties; to provide such a support which eliminates the requirement of rigid or semi-rigid shape maintaining structure such as stays, straps or sewn in elastic or impermeable compositions to prevent garment migration; to provide a material for such a support which has a skin-contacting surface having a high coefficient of friction as well as allowing breathability; to provide such a material which reduces garment migration; to provide such a which reduces the likelihood of skin irritation caused by shifting of the material against the skin; to provide such a material which imparts additional compression to a garment; to provide such a material which is coated with a matrix of tacky microdots; to provide such a material which is coated with a matrix of silicone microdots; to provide such a material which is coated with a matrix of tacky microdots in an identifying pattern; to provide such a material which is comfortable to wear; to provide such a material upon which the microdots are gravure printed with silicone; and to provide a method for making a material for such a support which is simple and efficient and economical to manufacture, which effectively provides a non slip yet breathable elastomeric surface, and which is particularly well-adapted for its intended purpose.  
           [0017]    Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention.  
           [0018]    The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a side elevational view of a support device in accordance with the present invention shown placed on the leg of a user, with a portion of the support laid back so as to illustrate the multilayer laminate construction thereof.  
         [0020]    [0020]FIG. 2 is a fragmentary side view of an inner surface of the support device.  
         [0021]    [0021]FIG. 3 is a fragmentary cross-sectional view of the support device, taken along line  3 - 3  of FIG. 1.  
         [0022]    [0022]FIG. 4 is a schematic diagram illustrating a method of making a multilayer laminate material for use in construction of the support device. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.  
         [0024]    The reference numeral  1  generally identifies a compression support sleeve in accordance with the present invention and the sleeve  1  is depicted in place over human leg knee joint area  2 . The sleeve  1  includes a generally tube-shaped member  3  of multilayer construction, having an upper end  4  and a lower end  5 . As best shown in FIGS. 1 and 3, a central film  11  is sandwiched between outer and inner adhesive layers  12  and  13 . A flexible and resilient film composition is required for the film  11  in order to permit stretching of the sleeve  1 , as it is put on and to accommodate movement of the underlying joint or limb during use. Polyurethane having a thickness of about 2 mil is preferred, although another suitable polymeric film may be employed and thickness may vary in accordance with desired characteristics of the sleeve  1 . The adhesive or heat and pressure sensitive glue layers are bonded respectively to outer and inner layers of elastomeric polymer material  14  and  15 . Any suitable adhesive which is compatible with both the polyurethane film layer  11  and the elastomeric polymer layers  14  and  15  may be employed. The polymer layers  14  and  15  are preferably constructed of a spandex fiber such as is sold under the trademark Lycra by DuPont Chemical Co., however, other materials function satisfactorily for the purpose.  
         [0025]    The outer elastomeric polymer layer  14  presents a smooth surface  21 , which facilitates free movement of clothing over the sleeve  1 , while providing resistance to abrasion and wear. Various constructions of sleeves having layers similar to layers  11 ,  12 ,  13 ,  14  and  15  have been previously offered by others for such devices as wet suits and medical devices. Such a sleeve of five layers is depicted in U.S. Pat. No. 5,735,807 of Cropper for use as a knee compression support, which is incorporated herein by reference.  
         [0026]    An inner, slip resistant surface  22  is formed by a layer of discontinuous microdots of a tacky substance  23 , which covers a substantial portion of the surface  21 . Silicone has been found to be particularly suitable for this purpose because it is extremely compatible with human skin, and may be compounded into an adhesive fluid for application which retains a slightly tacky surface when dry.  
         [0027]    The microdots  23  are spaced and preferably of generally circular configuration, having a diameter of from about 1 to 4 mils in thickness, preferably about 2 mils, and with a diameter of from about 10 to 50 mils in diameter with about 25 mils in diameter being preferred. The microdots  23  are imprinted upon the fabric by application of a preselected pressure which causes them to extend outwardly from the fabric surface  22  preferably about 2 mils. The microdots  23  are applied over substantially all of the inner surface  22  of the polymer layer  15 . Because of the elastomeric nature of silicone patterns when stretched, the silicone microdots  23  impart additional compression to the garment  1  and spacing facilitates breathing of the fabric. In certain embodiments, the size and distribution of the microdots  23  are varied in order to provide additional compression at predetermined locations. Such variable compression enables the garment to provide differential support is particularly desirable in certain applications such as, for example, ankle braces.  
         [0028]    While the microdots can be constructed of any material compatible with the skin a silicon rubber is preferable, especially a silicon rubber that is the reaction product of 5 to 10% VI/ST dimethyl-methylvinylsiloxane, 60 to 80% vinylpolydimethylsiloxane, 10 to 30% D 4  and HMDZ treated silicon dioxide reacted with 60 to 80% vinylpolydimethylsiloxane, 5 to 10% VI/ST dimethylvinylsiloxane, 1 to 5% polymethylhydrogensiloxane and 10 to 30% D4 and HMDZ treated silicon dioxide. Such a composition is available from Enterprise Coatings Co. Ltd.  
         [0029]    While normally not necessary with the microdots  23 , the sleeve  1  may also include one or more ribs or stays  24 , which are formed of a flexible synthetic resinous material to impart additional rigidity and support to the garment or assist in application of the sleeve  1  to the knee joint  2 . The stays  24  are secured in place on either side and at the ends by seams  25 , which may be sewn or fusion welded. One or more loops  26  extend upwardly from sleeve upper end  4  to facilitate pulling the garment on and positioning it snugly in place over a selected limb or joint.  
         [0030]    While a generally tubular sleeve  1  has been depicted and described, those skilled in the art will appreciate that such compression support garments may be fabricated to include gussets or seams or in the form of stockings, spiral constructions for use on the ankles and elbows as well as planar bandages which may be wound around a limb or joint in overlapping fashion and held in place by hook and loop fasteners or clips.  
         [0031]    A method of manufacture of the material of sleeve  1  is depicted schematically in FIG. 4 which includes providing a substrate  32  having suitable release properties to permit casting and easy removal of a polyurethane solution. The substrate  32  is preferably supplied on a spool  33 . As the substrate  32  is unrolled into an assembly line, it passes a spray station  34 , which applies a polyurethane fluid  35  to one surface of the substrate  32 . The polyurethane coated substrate  32  passes through a series of drying ovens  36  and  37 , which dry the polyurethane  35  into a 2 mil film  38  on the substrate  32 .  
         [0032]    The film-coated substrate passes a spray station  44 , which applies an adhesive solution  45  onto the surface. Preferably, the station  44  sprays adhesive solution  45  onto the film-coated substrate in an even, continuous layer. In other alternate embodiments, the spray station  44  may be operated intermittently or the distance between the spray heads may be set to deliver a discontinuous layer of adhesive solution  45 . Once coated with adhesive solution  45 , the polyurethane film-coated substrate  32  passes through a second series of ovens  46  and  47 , where the solvent is evaporated from the adhesive solution to form an adhesive layer  48 .  
         [0033]    Elastomeric fabric  54 , such as a spandex fiber of about 20 mils, is supplied, preferably on a spool  55 . Knitted nylon tricot fabric, especially as sold under the trademark LYCRA by E. I. DuPont de Nemours, is preferred because it provides a superior laminate construction which is long wearing and extremely comfortable to the wearer, although any other suitable knitted, woven or nonwoven fabric such as cotton, rayon, other stretchable synthetic fiber or blend thereof may be employed. The fabric  54  is unwound onto the surface of the adhesive layer  48  and is pressed into the adhesive  48  at elevated temperature by a series of rollers  56  and  57  to form a fabric/adhesive/film laminate  58 . The laminate  58  is then stripped from the substrate  32 , exposing an uncoated polyurethane film surface  59 .  
         [0034]    The laminate  58  passes a spray station  65  which again sprays an adhesive solution  66  onto the uncoated polyurethane film surface  59 . Once coated with adhesive solution  66 , the laminate  58  passes through a third series of drying ovens  67  and  68 , where the solvent is evaporated from the adhesive solution to form an adhesive layer  69 .  
         [0035]    Additional elastomeric tricot fabric  75  of about 20 mils in thickness is supplied on a spool  76 . The fabric  75  is unwound onto the surface of the adhesive layer  69  and is pressed into the adhesive  69  by rollers  77  and  78  to form a fabric/adhesive/polyurethane/adhesive/fabric laminate material  79 .  
         [0036]    The silicone microdots  23  are applied to one of the fabric surfaces of the laminate  79  by a process such as gravure printing. In the preferred rotogravure method, a suitably compounded silicone fluid  85  is supplied in a trough  86  for imprinting onto one surface of the laminate. Silicone is preferred because of the compatibility of its cured silicone gel with the skin and because the cured gel retains a slightly tacky surface having a high coefficient of friction against the skin.  
         [0037]    A first rotating cylinder  87  rests in the trough  86 , and by rotary movement thereof, its surface receives a coating of the silicone  85 . A second rotating cylinder  88 , is positioned in contact with cylinder  87  and elevated slightly above the trough  86  so as to receive a coating of the silicone solution  85  from the first cylinder  87  during rotation, and to permit any excess solution to drain back into the trough  86 . A rotating gravure cylinder  89  is positioned so as to make contact with cylinder  88  as well as the surface of laminate  79  during its rotation.  
         [0038]    The surface of cylinder  89  is etched or engraved to form a preselected pattern of spaced, generally circular recesses  95 , each having a predetermined diameter and depth. As gravure cylinder  89  rotates against cylinder  88 , the recesses  95  are filled with silicone  85 . A doctor blade  96  removes the excess silicone  85  from the surface of the gravure cylinder  89 , but not from the recesses. Continued rotation of the gravure cylinder  89  brings the silicone filled recesses  95  into contact with the surface of laminate  79 , where the silicone  85  is imprinted as raised silicone microdots  23 .  
         [0039]    Gravure cylinder  89  exerts a preselected pressure against the laminate  79  during the printing process in order to achieve a selected depth of imprint of the microdots  23  into the laminate  79 . In this manner, the depth of the recesses  95  and imprinting pressure cooperatively determine the depth of the imprinted microdots  23  on the surface of the imprinted laminate  97  The size, depth, distribution and arrangement of the recesses  95  on the gravure cylinder  89  may be preselected to imprint microdots  23  in any desirable pattern which serves to reduce garment migration, provide additional areas of compression, or even to provide brand identification.  
         [0040]    The imprinted laminate  97  passes through a series of circulating air ovens  98 ,  99  for evaporation of any solvent residue and curing of the silicone solution to a tacky gel. The laminate  97  is then wound onto rolls  100  of manageable size. The silicone imprinted laminate  97  may also be joined under heat and pressure with a release-coated protective backing prior to winding on rolls  100 . The backing may be removed after complete cure of the silicone, to expose a multilayer laminate material having a permanently tacky imprinted surface with spacing between the dots to facilitate breathing of the material.  
         [0041]    The material thus produced may be formed into completed sleeves  1 , stockings and other types of compression support having sewn or fused darts, gussets, and seams. The supports may also include fasteners such as for example, hooks, zippers, buttons and the like.  
         [0042]    It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.