Abstract:
The invention relates to a protective knit glove and methods of manufacturing thereof. The protective knit glove includes a knit glove shell having inner and outer surfaces; and a plurality of discrete rigid plates separated from each other by gaps of approximately 5 to 40 mils and directly adhered to the inner and/or outer surfaces. One or more rubbery layers may be directly adhered to one or more of the rigid plates. Preferably, the knit glove shell may be constructed from polyamide, cotton and polyurethane, polyaramid, ultra high molecular weight polyethylene, or glass fiber. Preferably, the discrete rigid plates may be made from epoxy and the rubbery layer may be made from nitrile rubber, polyurethane rubber, PVC rubber, or natural rubber. The protective knit glove provides a higher level of cut protection, added puncture protection and enhanced abrasion resistance compared to a glove without the discrete rigid plates.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) to pending Provisional Patent Application No. 60/991,376, filed on Nov. 30, 2007, by Steven R. VanErmen, the entire disclosure of which is incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Protective gloves are commonly used by workers in many industries to prevent/minimize hand injuries. One popular type of protective gloves is a knit glove made with yarns of high performance fiber such as polyaramid (Kevlar®), Para-Aramid (Twaron) or Ultra-High-Molecular-Weight-Polyethylene (UHMWPE, Spectra® or Dyneema®). These fibers are often combined with Nylon, Fiberglass or other commonly available fibers. These gloves provide cut protection because of the high tensile modulus and strength of the specialty fiber, while also maintaining the benefit of being form-fitting and comfortable, which is characteristic of a knitted construction. Glass or steel fibers are sometimes used in combination to boost cut resistance. Such knitted gloves are often combined with an elastomeric coating layer in and around the palm area to provide grip and also improved abrasion resistance. Typically the materials used in the elastomeric coating layer are nitrile rubber, polyurethane, PVC, or natural rubber. The coating may be applied by a well-known dipping process. 
         [0003]    Such gloves have inherent limitations. Cut resistance is dependent on the amount of fiber that fills the cross section of the yarn. The specialty fibers are fairly rigid, therefore there is a limit on how much fiber can fit into the cross section of the yarn before the knit glove becomes too stiff, bulky, and uncomfortable. Such gloves also provide little protection against puncture. The gaps and holes between yarns in a knit construction provide little to no resistance to sharp, pointed objects such as a needle, glass tip or metal tip. Specialty fibers are usually expensive, which increases the cost of gloves. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    The present invention provides a protective knit glove with closely spaced apart rigid plates that impart exceptional physical/mechanical properties. 
         [0005]    Optionally, a rubber or other elastomeric material may be applied to the rigid plates and/or to other areas of the knit glove shell to provide a protective glove with additional properties such as enhanced abrasion resistance, a fluid barrier, and/or an improved gripping property. 
         [0006]    The advantages of the invention are accomplished with or without incorporating expensive specialty fibers such as polyaramid, Para-Aramid or UHMWPE in the base knit glove. Knit gloves made with inexpensive cotton or nylon yarns can be used as a base for a highly protective glove within the scope of the present inventions. 
         [0007]    One aspect of the invention is a protective knit glove comprising a knit glove shell having inner and outer surfaces; a plurality of discrete rigid plates directly adhered to the inner surface, and/or outer surface; and optionally one or more rubbery materials directly adhered to one or more of the rigid plates and/or other areas of the knit glove shell. 
         [0008]    These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a protective knit glove of the invention with a typical outer rubbery coating. 
           [0010]      FIG. 2  is a perspective view of an alternative protective knit glove without the outer rubbery coating. 
           [0011]      FIG. 3  shows the cross-section view of the protective knit glove with rigid plates adhered to the outer surface of the knit glove, and an outer rubbery coating. 
           [0012]      FIG. 4  shows the cross-section view of a protective knit glove with rigid plates adhered to the inner surface of the knit glove and an outer rubbery coating. 
           [0013]      FIG. 5  shows the cross-section view of a protective knit glove with rigid plates adhered to both the outer and inner surface of the knit glove and an outer rubbery coating. 
           [0014]      FIG. 6  is a perspective view of another alternative glove in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. 
         [0016]      FIG. 1  illustrates a typical construction of the protective knit glove  10 A with a plurality of spaced apart rigid plates  14  directly adhered to an area on the outside surface of a knit glove shell  12 . The base of the construction is the knit glove shell  12 , which can be made using an automated knitting machine. The yarns used to make the knit glove can be made with cotton, cotton/lycra, polyamide (Nylon), polyaramid (Kevlar®), Para-Aramid (Twaron), ultra-high molecular weight polyethylene (UHMWPE, Spectra®, Dyneema®), glass, or other high fibers. Optionally, combinations of these fibers and sometimes steel fibers can be used. In addition, the knit glove shells used may be homogenous, meaning comprised of a consistent set of yarns/fibers, or may use different types of fibers in different areas of the glove as permitted by current and future glove knitting machinery (for example, using lower cut resistant fibers in areas of the glove to be covered with the rigid plates). 
         [0017]    Rigid plates  14  are made from materials that are highly cut, puncture and abrasion resistant, and optionally heat and flame resistant. Typically a polymeric composite is used for this purpose. As a preferred embodiment, a thermoset epoxy polymer reinforced with inorganic particles (such as silica and other inorganic oxides) is used as a plate material due to its high protective performance, ease of processing and economy of cost. Other resin composite systems, such as acrylate or phenolic, can also be used. It is generally preferred that the tensile strength of the plate material exceeds 100 kg/cm 2 . 
         [0018]    To provide cut and puncture protection, the spacing between plates is controlled such that a knife blade or a sharp cutting edge cannot easily pass between the plates. However, because the plates are rigid, the dimensions of the plates are controlled within a certain range that imparts suitable flexibility and comfort for the wearer. It has been found that a balance of parameters can be achieved for the plate arrangement such that good performance is realized without sacrificing comfort. The plates are typically chosen such that they are approximately uniform in size, and have a diameter in the range of 40 mils to 120 mils. The thickness of the plates is in the range of 5 to 40 mils. The gaps between plates are preferably approximately uniform in size, with a range typically between 5 to 20 mils. Various geometric shapes and patterns of the plates can be used for this purpose. 
         [0019]    The application of the rigid plate materials is usually done via a screen printing process. Here the thermoset polymer composite is premixed as a paste suitable for screen printing. A screen as typically used in the screen printing industry is mounted and the printing pattern on the screen is predetermined (e.g., to provide an array of hexagonal-shaped plates). The thickness of the screen film is chosen in order to yield appropriate thickness for the printed plates. The plates are printed onto one or more areas of the knit glove shell (for example, the palm) with the wet premixed polymer composite paste. The printed shell is then moved to a precuring station where the paste is cured and hardened sufficiently for handling. The glove may optionally have an additional printing in another area or areas of the glove. Depending on the intended use of the protective glove, it is often necessary to have protective plates on certain specific areas such as thumb crotch, etc. To cover all the required protective areas sufficiently, it may be necessary to print on the entire knit glove or in multiple areas of the knit glove. In this case, other screens with patterns that are specifically designed for each printed area of the glove are used. After the second printing, the wet printed plates are again precured and hardened. The glove is then removed from the printer and placed in an oven (batch or continuous) for further pre-setting and/or final curing. An example of the printed glove  10 B is shown in  FIG. 2 . 
         [0020]    The example of plate printing given above is for the case of heat-cured polymer composites. Other polymer composite systems, such as UV or electron-beam cured resins, can also be used. In such cases, the printing machines and processes shall be changed accordingly. 
         [0021]    The printed and precured knit glove may optionally be loaded on a three dimensional hand-shaped former for final curing such that it retains a desired shape, such as the pre-curved shape of the hand. Such cured glove may then be loaded onto an additional former for coating. 
         [0022]    The printed and cured knit glove may then be loaded on a three dimensional hand-shaped former, and sent through an elastomeric dip-coating machine to provide a rubbery or elastomeric outer layer. Afterward, it may be sent through an oven drying station for drying and/or final curing of the elastomeric or rubbery coating. 
         [0023]    This outer rubbery coating may be applied for several reasons. Although the rigid plates provide excellent cut, puncture, and abrasion protection, it is not always appropriate as the outermost layer of the glove due to the lack of grip in some situations. The rubbery coating layer, utilizing nitrile, urethane, PVC or natural rubber, can provide improved grip, a fluid barrier, and/or added abrasion resistance. 
         [0024]    In some applications, it is important that the glove acts as a fluid barrier for chemical protection or other purposes. In this case, complete and continuous coverage of the palm and part or all of the back hand areas is suitable. However, a discontinuous pattern of the rubbery coating layer is sometimes used in situations, e.g. where breatheability is more important than the fluid barrier functionality. 
         [0025]    In some special situations (such as handling cable wires), the exposed rigid plates may actually have an advantage in purposely providing a desired degree of slip. Also in certain wet or oily grip situations, rigid plates may provide better grip. In addition, oftentimes gloves with only the rigid plates may be incorporated inside of a glove as a glove liner (whether permanently attached or worn as a first glove under a second outer glove). In these situations, gloves with only the rigid plates may be adequate and suitable. Thus, the inventors contemplate gloves without a rubber elastomeric coating, gloves that are completely coated with an elastomeric or rubbery material, and gloves that are partially coated with a rubbery or elastomeric material. 
         [0026]      FIG. 3  shows the cross section view of a section of knit glove  10 . The rigid plates  14  are discrete and adhere to an outer surface of the knit glove shell  12 . Outer elastomeric or rubbery coating material  16  can be continuous or discontinuous. Part of the rubbery coating material  16  adheres to the top of the rigid plates  14 , and part can be attached to the yarns or fibers of knit glove shell  12  in the gap area between the discrete rigid plates. 
         [0027]    It has been observed that sometimes the outer rubbery coating material  16  may not be compatible in terms of bonding with the rigid plates  14 . In this case, the rigid plates  14  may be adhered to the inner surface of the knit glove shell  12 , with the rubbery coating material  16  on the outside, as is shown in  FIG. 4 . In this situation, it is often found necessary to use a separate inner liner (not shown) to prevent direct skin contact with the rigid plate to minimize skin abrasion. 
         [0028]    To provide a high level of cut and/or puncture protection, the rigid plates can sometimes be placed on both the inner and the outer surfaces of the knit glove material, as is shown in  FIG. 5 . 
         [0029]    The knit glove base shell  12  can be made with widely available and common cotton or nylon yarns, with specialty polymers films such as polyaramid or UHMWPE, or blends of common and specialty fibers. A cotton or nylon knit glove on its own has practically no cut protection. However, combined with the rigid plates, and optional rubbery or elastomeric material, as described in the present embodiments of the invention, it can be transformed into a high performance protective glove with cut, puncture and abrasion resistance that can match or even exceed protective gloves made with specialty fibers. For example, a nylon shell knit glove on its own has a cut resistance of less than 400 g (ASTM F-1790 cut test). However, a cut resistance of over 3000 g (ASTM F-1790 cut test) was accomplished using a nylon shell knit glove and an epoxy-based composite plate coating. In comparison, typical cut protection of polyarmid-based (with steel fiber reinforcement) knit glove is rated at about 2000 grams. When polyaramid or UHMWPE knit shells are used, even higher levels of cut protection can be achieved by directly adhering rigid plates  14  to a glove shell  12  in accordance with the invention. 
         [0030]    In designing the protective glove, the protection level in different zones (palm, back of the hand, thumb crotch, etc.) of the glove can vary depending on the applications. This can be accomplished by varying the knit fibers (multi-fiber zones), and also in printing the rigid plates in different zones (zone printing). By doing so, often an optimally designed glove can be achieved balancing the needs for both performance and cost. 
         [0031]    Shown in  FIG. 6  is another embodiment of the invention in which glove  10 C includes plates  14  disposed on a back side of the glove that would cover the back of a wearer&#39;s hand during use and a rubbery coating material  16  covering a substantial portion of the palm area of the glove. In accordance with aspects of this invention, plates  14  may be arranged in arrays on one or multiple areas of the glove shell  12 , and any particular array of plates may be provided with a rubbery coating  16  or partially provided with a rubbery coating  16 . 
         [0032]    Various modifications and variations of the described glove embodiments and the method of making the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. It is understood, however, that examples and embodiments of the present invention set forth above are illustrative and not intended to confine the invention. The invention embraces all modified forms of the examples and embodiments as falling within the scope of the following claims.