Abstract:
A method of applying a bittering agent to a substrate provided by an item which it is desired to impregnate in order to prevent, for example, chewing of the item, is disclosed. The method comprises the steps of: applying a first coating layer to the substrate, the first coating layer being of a substance that can be treated to acquire a hardened state; applying a bittering agent to the first layer; and treating the first coating layer thereby to generate the hardened state.

Description:
BACKGROUND TO THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to the treatment of items to make them unpleasant to taste. One example of the use of the present invention, but by no means the only such example, is the treatment of items which have common use in domestic circumstances such as buttons, zips, television remote controls, computer mice. Items such as this, their common usage domestically notwithstanding, might, if ingested become dangerous, particularly to small children. 
         [0003]    2. Description of Related Art 
         [0004]    Typically, such items are rendered unpleasant to the taste as a result of treatment with a bittering agent. Such agents are known per se and can be applied, as a lacquer or varnish to, for example, fingernails. It is also known to apply such agents to children&#39;s toys, for example, either by applying the agent as a ‘top layer’ to the item, or by mixing the agent with an epoxy, acrylic or water-based coating which is then applied to the surface of the item. It has been found that, by using this method, where the agent is mixed with either a water-based, epoxy or acrylic coating, the effectiveness of the bittering agent is significantly reduced and, accordingly, relatively large quantities of the agent are then required in order to produce the requisite bitterness. This, in turn, has a negative impact upon the security (i.e. safety) of the coating. 
       SUMMARY OF INVENTION 
       [0005]    A first aspect of the present invention provides an alternative method of applying a bittering agent to coat items in order to impart an undesirable, bitter taste to them. According to a first aspect of the present invention there is provided a method of applying a bittering agent to a substrate provided by an item which it is desired to impregnate in order to prevent, for example, chewing of the item, the method comprising the steps of: applying a first coating layer to the substrate, the first coating layer being of a substance that can be treated to acquire a hardened state; applying a bittering agent to the first layer; and treating the first coating layer thereby to generate the hardened state. 
         [0006]    A further aspect of the present invention provides an item such as a zip slider impregnated with a bittering agent. According to an embodiment of the present invention there is provided an item comprising a substrate to which a first coating is applied, the first coating being a material which has been treated to become hardened, and the first coating being impregnated with a bittering agent. 
         [0007]    Embodiments of the present invention will now be described, by way of example, and with reference to the accompanying drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0008]      FIG. 1  is a flow chart illustrating an embodiment of method according to the present invention; 
           [0009]      FIG. 2  is a schematic representation of an apparatus used in the method illustrated in  FIG. 1   
           [0010]      FIG. 3  is a section through the surface of an item treated with the method of  FIG. 1 ; 
           [0011]      FIG. 4  is a perspective view of a zip slider according to an embodiment of the present invention 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0012]    Referring to  FIG. 1 , the first step in the process is the step  10  of loading parts to be coated into a hot barrel spraying apparatus. In the present example, the parts or items to be coated are parts of a zip, such as a slider and a pull tab for a zip slider (whether in conjunction with the slider or separately or on its own), though a very wide range of items finds use in the present method. The apparatus is illustrated schematically in  FIG. 2  and includes a barrel  200 , mounted for rotation relative to a base  202 . The barrel  200  includes a single nozzle or plurality of nozzles  204 , each of which is adapted to emit a fine spray of a substance with which the items are to be coated. The precise nature of the coating to be applied to the items will depend upon the uses to which they are to be put. A typical coating according to embodiments of the present invention is of a kind that, although applied in this manner, is subsequently capable of acquiring a hardened state, such as a vitrified state or a state equivalent to that. One example of a group of such coatings are those that can be cured to acquire the aforementioned hardened state, where curing is achieved, for example, by the application of heat, suitable chemical additives, the application of ultra-violet light or other radiation, the application of electron beams or any other suitable manner. 
         [0013]    In the present example the coating is a coat of epoxy resin coating (paint), though in alternative embodiments the coating could equally be of another suitable material, such as a clear epoxy or acrylic lacquer coating for example, or enamel. In order to provide the appropriate conditions under which to apply that coating, the interior of the barrel  200  is heated by a suitable heating apparatus (not shown). The barrel then rotates during the heating process to ensure the provision of as uniform a coating to the items as possible. 
         [0014]    The items are then rotated and coated within the barrel  200 , at step  20 , for a period of time sufficient to apply to them a coat of the requisite thickness. Optionally, this process may be repeated a sufficient number of times in order for the items to have the required number of coats applied to them. Hot barrel spraying is, however, only one method of applying a coating and other suitable methods may be employed. Ordinarily, at this stage in a coating process, the items will then be cured by heating to the same or a significantly higher temperature, for example in suitable kiln or retort. 
         [0015]    According to the present embodiment, however, at this point, shortly after completion of the coating step and, preferably immediately the coating step is completed, at step  30 , a coating of the bittering agent is then applied to the items. In the present embodiment, the bittering agents is sucrose octa-acetate in a concentration of in the range 20-50 ppm. Other bittering agents, such as denatonium benzoate or denatonium saccharide may be employed; or any other suitable bittering agent which is not harmful to ingest. 
         [0016]    The addition of the bittering agent may also be performed in the hot barrel apparatus. Alternatively, the coating may be applied by another suitable method consistent with the nature of the bittering agent and the uncured coating to which the bittering agent is to be applied. The bittering agent is sprayed onto the uncured coated materials for 1 to 2 minutes, with in the present example in which the item is a zip slider, around 2-3 ml of bittering agent are being used per load/batch. This step will result in the coating being impregnated with the bittering agent. 
         [0017]    At step  40 , the items are then cured in the hot barrel for a period of time at a given temperature suitable to the coating applied or placed in a kiln or other suitable heating retort in order to cure the coatings for a suitable period of time and at a suitable temperature having regard to the nature of the item. For example, in the case of Epoxy Coating a 10 minute cure cycle is used in the hot barrel, with a half rotation every 1 minute and then this is followed by a 30 minutes cure cycle at 100° C. in a kiln. 
         [0018]    Referring to  FIG. 3 , the result of the process described above is that, to the metal substrate (in this example aluminium of a zip slider, and therefore may also comprise an upper layer of aluminium oxide)  300 , there is then applied an enamel coating  310  and the upper layer  320  of this is covered with a bittering agent. It has been found that, in the above-described embodiment, as the bittering agent layer  320  is applied directly to the softened uncured enamel coating layer  310 , so this allows the bittering agent layer  320  to impregnate the enamel surface, but not distribute through the full coating and so only a small amount is needed for this to be effective, as it seeps into the top surface of the coating only. In addition, the coating is more durable to washing and so the bittering agent properties will also remain effective as it is embedded in the surface of the coating. 
         [0019]    This is also possible with plated components that are coated with clear epoxy/water based or acrylic lacquers and then sprayed with bittering agents before the coating is fully cured. 
         [0020]    The bittering agent can also be mixed with other additives at the same time i.e. a mixture of wax and bittering agent can be applied at the same time to give both lubrication and bitter taste at the same time. 
         [0021]    The process of the present invention finds application in the treatment of items that, for example, for safety reasons, it is undesirable for a child to chew, such as a zip slider, for example but also finds applicability in connection with a cornucopia of other items including buttons and other garment fasteners or parts thereof, computer mice, remote controls, the tops of bottles (such as those containing harmful substances), pen tops or (which may be useful to break a habit of chewing, even in grown ups).