Abstract:
A waterproof safety boot includes a one-piece EVA upper ( 11 ) to which is applied a toe cap ( 15 ). A polyurethane toe cap cover ( 19 ) is secured to the upper to encapsulate the toe cap. An outsole ( 25 ) of e.g. synthetic nitrile rubber may be added. The upper may be a booty.

Description:
BACKGROUND 
       [0001]    This invention relates to footwear having a strengthened toe cap, and to a method of manufacture thereof. In a second aspect, the invention relates to footwear having a toe of contrasting colour. 
         [0002]    A characteristic of safety footwear is the provision of a strengthened toe cap. Typically a domed reinforcement of steel is incorporated at the toe of the footwear, for example a boot, to provide protection against crushing. Legislation requires that the reinforcement is incorporated in the footwear in such a manner that it cannot be removed without damaging the footwear; in practice the reinforcement is anchored against relative movement within the footwear, so as to prevent tipping of the reinforcement and consequent injury to the foot of the wearer. In one example a conventional work boot comprises an assembly of parts which are retained in appropriate juxtaposition by sewing and/or adhesive. 
         [0003]    A strengthened toe cap can be provided in many kinds of footwear, and the upper (the part of the footwear above the sole) may range from a front foot covering of a slip-on clog, through a conventional shoe or ankle boot, to the substantial leg cover of a wellington boot or wader. 
         [0004]    In cases where absolutely waterproof footwear is required, it is known to provide the upper as a moulded plastics booty to encase at least part of the foot. Such a booty may have an integral tread, or have an outsole applied thereto. 
         [0005]    Several kinds of moulded waterproof boot are known, consisting of or incorporating a one piece booty. An inexpensive boot may be moulded in PVC (polyvinylchloride) by single injection moulding, and have a non-slip rubber outsole fixed thereto by adhesive. Such a boot may be moulded around a protective toe cap (typically of steel), which adheres as the plastics material is cured, and is thus fixed against relative movement within the boot. A significant disadvantage of PVC footwear is weight, and such footwear is also somewhat fatiguing to wear because the level of cushioning underfoot is relatively low. A cushioning in-sole may be fitted, but this adds both cost and weight. Footwear of PVC is also undesirable because it does not easily decompose upon disposal, and has other poor environmental aspects. 
         [0006]    An alternative moulded boot comprises a one-piece polyurethane (PU) moulding with integral outsole. Such a boot is expensive compared with a PVC boot, but is lighter and can also incorporate a protective toe cap which is adhered in the moulding operation. One disadvantage of a PU sole is that it is not the optimal material for slip resistance in a wet environment. Another disadvantage is that the PU grade for the leg portion is generally different from the foot portion, so as to ensure that the leg ‘stands up’ in use; this results in additional complication and difficulty during moulding. 
         [0007]    One characteristic of an in-moulded toe cap is that the position of the toe cap insert cannot be seen after moulding. Accordingly the footwear must be cut open for the purpose of inspection, and confirmation of a correct moulding operation. Furthermore an in-moulded toe cap substantially stiffens the toe of the footwear, and may result in difficulty in releasing the footwear from the mould. A solution to this problem is the adoption of a mould shape that facilitates removal of the footwear from the mould, but such a mould may not be ideally suited to the shape of a foot. 
         [0008]    It has also been proposed to mould footwear of EVA (ethyl vinyl acetate). Such footwear is light and has very good dimensional stability, good cushioning characteristics, and an excellent external finish. However a reinforced toe cap will not adhere to the plastics material during moulding, and is thus not fixed relative to the footwear as is consequence of legislation. 
         [0009]    A characteristic of an EVA moulding is that it expands substantially upon release from the mould, so that an in-moulded toe cap is very unlikely to be retained in the correct position, or the surface of the EVA moulding may become distorted. Consequently a reinforced toe cap must be inserted into an EVA booty after moulding, which is somewhat difficult. Furthermore to ensure stability such a reinforced toe cap is pre-attached to a hard mid-sole board, which increases the difficulty of insertion post moulding, and may further require a cushion insole for comfort of the user. 
         [0010]    It would be desirable to provide a strengthened toe cap to footwear having a moulded EVA upper which addresses the difficulties noted above, and in particular to provide an improved lightweight waterproof boot with a strengthened toe cap, at relatively low cost. 
         [0011]    A further requirement of safety footwear, particularly those kinds used in the food industry, is the need for segregation according to particular factory operations. Thus footwear worn in a preparation area for raw meat should not also be used in an area associated with cooked food, Furthermore it may be necessary to distinguish footwear according to technical features thereof, for example type of material, type of reinforcement, strength, sole design etc. Some means of instant identification is typically required to meet industry standards, 
       SUMMARY OF PRESENTLY DESIRABLE EMBODIMENTS 
       [0012]    According to one aspect of the invention there is provided footwear comprising a one-piece moulded EVA upper having a rigid toe cap applied to the exterior thereof, and a toe cap cover applied to the exterior of said toe cap, the edge of said cover being affixed to said upper. 
         [0013]    Such footwear is relatively inexpensive and avoids the disadvantages of moulding from PVC or PU. The rigid toe cap, preferably a shell of steel, aluminium or a composite, is applied from the outside after the EVA upper has cured, and is in use trapped by the toe cap cover. A suitable adhesive, such as polyurethane resin or a two part epoxy, is used to attach the toe cap to the upper and the toe cap cover to the assembly of upper and toe cap. 
         [0014]    The EVA moulding also provides a comfort lining to the inside face of the rigid toe cap, thus obviating attachment of an additional internal component. 
         [0015]    By applying the toe cap from the exterior, correct positioning is assured, and thus quality control of the footwear is improved. Destructive testing to determine toe cap position is not necessary, and a wider range of toe cap material is possible since the toe cap is not exposed to high mould temperatures. Furthermore a footwear mould can be better matched to the foot shape since an allowance for easing the rigid toe cap from the mould is not required. Insertion of a toe cap into a moulded booty is obviated, along with the prior art mid-sole board. 
         [0016]    The upper may comprise a one-piece moulded EVA booty, so as to make the footwear waterproof. 
         [0017]    In one embodiment a synthetic rubber outsole is applied to the EVA upper, so as to give increased slip resistance and wear properties according to the surface on which the footwear is used. 
         [0018]    In one embodiment the EVA upper includes a recessed toe region adapted to receive and locate the toe cap so as to give a flush junction. This arrangement further improves location and retention of the toe cap on the upper. The toe cap may extend on the underside of the booty in a recess thereof to provide a substantially flush surface for attachment of a sole. 
         [0019]    In a presently preferred embodiment, the toe cap includes an interned flange at the lower peripheral edge, said flange being adapted to fit under the toe of the upper, so as to improve location and retention of the toe cap. The flange may be continuous, and in the width range 4-8 mm. 
         [0020]    The toe cap cover is in one embodiment a separately moulded plastics or synthetic rubber moulding of for example polyurethane. Such a moulding can be self coloured and provide a suitable means of distinguishing boots of different kind, for different factory areas or different uses. The toe cap may be a suitable relatively hard and durable material, and may be patterned or ribbed. 
         [0021]    In a second aspect the invention provides footwear comprising a one piece moulded upper of one colour, and having adhered thereto a moulded toe cap cover of a contrasting colour. This aspect of the invention permits all kinds of moulded boot to be distinguished in use, since a wide range of colours and patterns may be adapted for the toe cap cover. 
         [0022]    According to a third aspect of the invention there is provided a method of manufacture of a waterproof safety boot comprising moulding a one-piece upper of EVA, adhering a steel toe cap to the exterior of said upper, and adhering a toe cap cover of polyurethane to said toe cap, said cover being adhered at the periphery thereof to said upper. 
         [0023]    For the avoidance of doubt, by ‘upper’ is meant the upper visible part of the footwear, which may be attached to a sole to form an enclosure for a foot, or may be in the form of a booty to encircle at least the toes and fore part of the foot. In many cases, a booty will comprise at least an enclosure of the foot, from toe to ankle, and may further include a leg covering. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    Other features of the invention will be apparent from the following description of a presently preferred embodiment illustrated by way of example only in the accompanying drawings in which: 
           [0025]      FIG. 1  is a boot according to the invention, in &amp;de elevation. 
           [0026]      FIG. 2  is an illustrative transverse cross-section on line  2 - 2  of  FIG. 1 . 
           [0027]      FIG. 3  is an illustrative transverse cross-section on line  3 - 3  of  FIG. 1 . 
           [0028]      FIG. 4  is an illustrative transverse cross-section on line  4 - 4  of  FIG. 1 . 
           [0029]      FIG. 5  is an illustrative transverse cross-section on line  5 - 5  of  FIG. 1 . 
           [0030]      FIG. 6  is an illustrative longitudinal cross-section through the boot of  FIG. 1 . 
           [0031]      FIG. 7  is an enlarged cross-section of the toe of the boot of  FIG. 1 . 
           [0032]      FIG. 8  is an enlarged front elevation of the boot of  FIG. 1 . 
           [0033]      FIG. 9  illustrates an alternative to the toe of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0034]    The following description of the invention is in relation to a wellington boot. It will however be understood that the invention is suitable for many kinds of safety footwear, including clogs, slip on shoes, laced shoes, ankle boots, wellington boots and waders. 
         [0035]    With reference to the drawings, a wellington boot  10  comprises a one-piece booty  11  moulded by ethyl vinyl acetate (EVA). The booty is moulded as a single shot in order to ensure that no seams, joins or other junctions can impair the ability of the boot to withstand water ingress when immersed. The wall thickness of the booty is selected according to the intended duty; thus the heel portion  12  is thickened for comfort, and the front upper face  13  is relatively thick as compared to the rear wall  14  to give comparatively good impact resistance. The he&amp; portion may for example have a thickness in the range 15-25 mm. 
         [0036]    A steel toe cap  15  is adhered to the toe of the booty  11  from the outside, by adhesive. As best illustrated in  FIG. 7 , the booty is moulded with a corresponding depression  16  at the front outer surface, so that the toe cap fits flush around the substantially semi-circular rear edge thereof. The substantially semi-circular lower edge of the toe cap comprises an interned peripheral flange  18 , which fits under the booty  11  to give a degree of form fitting which assists in retaining the toe cap  15  in position. The flange is continuous and in the width range 4-10 mm. A recess is provided on the booty for the flange  18 , so as to allow an out-sole to be flush fitted. 
         [0037]    To the outside of the toe cap  15  is adhered a toe cap cover  19 , comprising a moulding of thermoplastic polyurethane (TPU). A TPU moulding is accurate and dimensionally stable, whilst giving improved impact and abrasion resistance as compared with EVA. An adhesive such as polyurethane or two-part epoxy is suitable. 
         [0038]    A further advantage of the toe cap cover  19  is that it may be colour coded to visually identify a boot with a specified use or factory area, whilst avoiding the necessity of providing means of identification on the EVA moulding. A self-coloured toe cap cover gives a permanent marking, unlike the application of an identifier to the surface of a boot, which may be damaged or rubbed off in use. For example the booty may be white, and the toe cap of a primary colour. 
         [0039]    Furthermore the differently coloured toe cap is in a position where it is always visible in use, notwithstanding that the boot leg may be covered or shielded by clothing. Additionally, the applied toe cap provides increased thickness, and may be moulded of a different material to give enhanced protection against wear or impact. 
         [0040]    As illustrated in  FIG. 7 , the cover  19  is tapered at the rear semi-circular edge  21  so as to be substantially flush and smooth with the surface of the booty, whilst giving an adhered band  22  ( FIG. 1 ) sufficient to overlap the toe cap  15 . The adhered band may have a width in the range 10-20 mm, and in practice is arranged in front of the region of the upper which flexes when walking. 
         [0041]    An outsole  25 , of for example synthetic nitrile rubber, is applied to the booty by conventional means, such as adhesive, and provides a final encapsulation for the toe cap  15 . In some instances the sole may provide an upstanding front bumper  26  ( FIG. 8 ), and in order to save material, the toe cap cover  19  may fit against, but not overlap this bumper  26  ( FIG. 7 ). In the alternative, the bumper  26  may be omitted, and the toe cap cover  19  may extend to the outsole ( FIG. 9 ). 
         [0042]    If desired the outsole may be a conventional composite or a multi-layer construction, for example synthetic nitrile rubber, polybutadiene rubber (BR9000) and styrene butadiene rubber. 
         [0043]    An insole may be fitted if desired, to improve comfort and insulation, and the booty may be lined. However EVA has good properties of thermal insulation and compliance, so that linings may be obviated. 
         [0044]    A mid-sole, for example a reinforced mid-sole to prevent piercing may be incorporated on the outsole and beneath the booty or insole. An integral insole of upstanding moulded projections may be provided to prevent slipping of the users foot in use. 
         [0045]    The material of the booty comprises typically a suitable grade of ethyl vinyl acetate with a polyester (PE) plasticiser. 
         [0046]    The toe cap cover is for example a polyurethane consisting of methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI) and a prepolymer (PPG220). 
         [0047]    A suitable adhesive is polyurethane (PU) resin, methyl ethyl ketone and ethyl acetate. 
         [0048]    The described embodiment relates to a moulded EVA booty, which comprises the upper of the footwear with an integral insole. The upper could however be conventional, in the form of a top covering, and attached to a sole. The toe cap and toe cap cover of the invention are applied to the upper in the same manner in both instances, and where necessary an outsole is added subsequently. 
         [0049]    In this description, use of boots having differently coloured toe caps is described in relation to food processing factories. The use of boots according to the invention is not limited to such factories. 
         [0050]    The upper part of the upper may be constituted by an alternative material, such as canvas, nylon or leather, In this way a composite upper may give a different aesthetic appearance whilst retaining the practicability and comfort of an EVA moulding with integrated reinforced toe cap. Such alternative materials may be attached by conventional methods, such as by in-moulding, adhesive or by stitching. 
       EXAMPLE  
       [0051]    The following example describes a wellington boot according to one embodiment of the invention. 
       Booty Moulding (EVA) 
       [0052]    Base material: 69.8% Ethyl Acetate+18.6% Poly Ester+11.6% Engage™ ethylene plastomer. 
         [0053]    Moulding temperature 175° C. 
         [0054]    Moulding duration 600-700 seconds. 
         [0055]    Density of moulded material 0.3 g/cm 3 . 
         [0056]    Hardness of moulded material SHA 55-60. 
         [0057]    Minimum thickness of material: 3 mm. 
         [0058]    Maximum thickness of material: 15 mm. 
       Over Cap Moulding (TPU) 
       [0059]    Material: 35.4% MDI (Methylene Diphenyl Diisocyanate)+46.1% TDI (Toluene diisocyanate)+18,5% PPG220 (polyoxypropylene propylene-glycol). 
         [0060]    Moulding Temperature 220° C. 
         [0061]    Moulding duration 150 seconds. 
         [0062]    Density of moulded material 1.1 g/cm 3 . 
         [0063]    Hardness of moulded material SHA 80-90. 
       Rubber Outsole: 
       [0064]    Material: 73.2% Nitro Rubber+7.2% BR 9000 (Butadiene Rubber)+19.6% SBR Rubber (Styrene Butadiene Rubber). 
         [0065]    Moulding temperature 150° C. 
         [0066]    Moulding duration 280 seconds. 
         [0067]    Density of moulded material 1.2 g/cm 3 . 
         [0068]    Hardness of moulded material SHA 60-65. 
       Steel Toecap: 
       [0069]    Material: mild steel with anti-corrosion surface treatment. 
         [0070]    Size 42 
         [0071]    approximate length 46 m 
         [0072]    approximate width 92 m 
         [0073]    approximate height 51.5 mm